[v7,2/2] soc/imx: Add GPCv2 power gating driver

Commit Message

Andrey Smirnov March 21, 2017, 2:50 p.m. UTC

Add code allowing for control of various power domains managed by GPCv2
IP block found in i.MX7 series of SoCs. Power domains covered by this
patch are:

    - PCIE PHY
    - MIPI PHY
    - USB HSIC PHY
    - USB OTG1/2 PHY

Support for any other power domain controlled by GPC is not present, and
can be added at some later point.

Testing of this code was done against a PCIe driver.

Cc: [e-mail]
Cc: Lucas Stach <[e-mail]>
Cc: Fabio Estevam <[e-mail]>
Cc: Dong Aisheng <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Andrey Smirnov <[e-mail]>
---
 drivers/soc/Kconfig      |   1 +
 drivers/soc/imx/Kconfig  |  10 ++
 drivers/soc/imx/Makefile |   1 +
 drivers/soc/imx/gpcv2.c  | 365 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 377 insertions(+)
 create mode 100644 drivers/soc/imx/Kconfig
 create mode 100644 drivers/soc/imx/gpcv2.c

Comments

Lucas Stach March 23, 2017, 2:35 p.m. UTC | #1

Hi Dong,

Am Freitag, den 24.03.2017, 14:24 +0800 schrieb Dong Aisheng:
[...]
> > +static struct platform_driver imx7_pgc_domain_driver = {
> > +	.driver = {
> > +		.name = "imx7-pgc",
> > +	},
> > +	.probe    = imx7_pgc_domain_probe,
> > +	.remove   = imx7_pgc_domain_remove,
> > +	.id_table = imx7_pgc_domain_id,
> > +};
> > +builtin_platform_driver(imx7_pgc_domain_driver)
> 
> Again, i have a fundamental question about this patch implementation
> that why we choose above way to register the power domain?
> 
> I'm sorry that i did not know too much history.
> Would you guys please help share some information?
> 
> Because AFAIK this way will register each domain as a power domain
> provider which is a bit violate the real HW and current power domain
> framework design. And it is a bit more complicated to use than before.
> 
> IMHO i would rather prefer the old traditional and simpler way that one
> provider (GPC) supplies multiple domains (PCIE/MIPI/HSIC PHY domain)
> than this patch does.
> 
> However, i might be wrong. Please help to clear.

This way we can properly describe each power domain with the regulator
supplying the domain and the clocks of the devices inside the domain in
the device tree.

This is needed as for the upstream version we are controlling the
regulator from the GPC driver, as opposed to the downstream version,
where each device has to implement the regulator handling and power
up/down sequencing.

See the rationale in the commits adding the multidomain support to the
i.MX6 GPC.

Regards,
Lucas

Dong Aisheng March 24, 2017, 6:24 a.m. UTC | #2

On Tue, Mar 21, 2017 at 07:50:04AM -0700, Andrey Smirnov wrote:
> Add code allowing for control of various power domains managed by GPCv2
> IP block found in i.MX7 series of SoCs. Power domains covered by this
> patch are:
> 
>     - PCIE PHY
>     - MIPI PHY
>     - USB HSIC PHY
>     - USB OTG1/2 PHY
> 

You probably may need drop USB OTG which is not claimed in current RM.
See the PGC definition in 5.5.10 GPC Memory Map section.

Each PGC (CPU type, MIX type, PU type) will occupy 64 Bytes address space,
the specific base address of each PGC are listed as below.
• 0x800 ~ 0x83F : PGC for A7 core0
• 0x840 ~ 0x87F: PGC for A7 core1
• 0x880 ~ 0x8BF: PGC for A7 SCU
• 0xA00 ~ 0xA3F: PGC for fastmix/megamix
• 0xC00 ~ 0xC3F: PGC for MIPI PHY
• 0xC40 ~ 0xC7F: PGC for PCIE_PHY
• 0xC80 ~ 0xCBF: Reserved
• 0xCC0 ~ 0xCFF: Reserved
• 0xD00 ~ 0xD3F: PGC for USB HSIC PHY

And in 5.4 Power Management Unit (PMU) chapter,
you will find the USB OTG phy power is directly supplied by
VDD_USB_OTG1_3P3_IN/VDD_USB_OTG2_3P3_IN.

http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX7DRM.pdf

I understand that there's also some USB OTG code exist in NXP internal
tree, but that's legacy for early doc implementation and may be deprecated.
so i assume it should be gone.

Hopefully i will double confirm with our IC designer tomorrow.

> Support for any other power domain controlled by GPC is not present, and
> can be added at some later point.
> 
> Testing of this code was done against a PCIe driver.
> 
> Cc: [e-mail]
> Cc: Lucas Stach <[e-mail]>
> Cc: Fabio Estevam <[e-mail]>
> Cc: Dong Aisheng <[e-mail]>
> Cc: [e-mail]
> Cc: [e-mail]
> Signed-off-by: Andrey Smirnov <[e-mail]>
> ---
>  drivers/soc/Kconfig      |   1 +
>  drivers/soc/imx/Kconfig  |  10 ++
>  drivers/soc/imx/Makefile |   1 +
>  drivers/soc/imx/gpcv2.c  | 365 +++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 377 insertions(+)
>  create mode 100644 drivers/soc/imx/Kconfig
>  create mode 100644 drivers/soc/imx/gpcv2.c
> 
> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
> index f09023f..8943543 100644
> --- a/drivers/soc/Kconfig
> +++ b/drivers/soc/Kconfig
> @@ -2,6 +2,7 @@ menu "SOC (System On Chip) specific Drivers"
>  
>  source "drivers/soc/bcm/Kconfig"
>  source "drivers/soc/fsl/Kconfig"
> +source "drivers/soc/imx/Kconfig"
>  source "drivers/soc/mediatek/Kconfig"
>  source "drivers/soc/qcom/Kconfig"
>  source "drivers/soc/rockchip/Kconfig"
> diff --git a/drivers/soc/imx/Kconfig b/drivers/soc/imx/Kconfig
> new file mode 100644
> index 0000000..bc7f0ee0
> --- /dev/null
> +++ b/drivers/soc/imx/Kconfig
> @@ -0,0 +1,10 @@
> +menu "i.MX SoC drivers"
> +
> +config IMX7_PM_DOMAINS
> +	bool "i.MX7 PM domains"
> +	select PM_GENERIC_DOMAINS
> +	depends on SOC_IMX7D || (COMPILE_TEST && OF)
> +	default y if SOC_IMX7D
> +
> +endmenu
> +
> diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
> index 35861f5..5b6e396 100644
> --- a/drivers/soc/imx/Makefile
> +++ b/drivers/soc/imx/Makefile
> @@ -1 +1,2 @@
>  obj-y += gpc.o
> +obj-$(CONFIG_IMX7_PM_DOMAINS) += gpcv2.o
> diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
> new file mode 100644
> index 0000000..a27c5f8
> --- /dev/null
> +++ b/drivers/soc/imx/gpcv2.c
> @@ -0,0 +1,365 @@
> +/*
> + * Copyright 2017 Impinj, Inc
> + * Author: Andrey Smirnov <[e-mail]>
> + *
> + * Based on the code of analogus driver:
> + *
> + * Copyright 2015-2017 Pengutronix, Lucas Stach <[e-mail]>
> + *
> + * The code contained herein is licensed under the GNU General Public
> + * License. You may obtain a copy of the GNU General Public License
> + * Version 2 or later at the following locations:
> + *
> + * http://www.opensource.org/licenses/gpl-license.html
> + * http://www.gnu.org/copyleft/gpl.html
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <dt-bindings/power/imx7-power.h>
> +
> +#define GPC_PGC_CPU_MAPPING	0xec
> +#define USB_HSIC_PHY_A7_DOMAIN	BIT(6)
> +#define USB_OTG2_PHY_A7_DOMAIN	BIT(5)
> +#define USB_OTG1_PHY_A7_DOMAIN	BIT(4)
> +#define PCIE_PHY_A7_DOMAIN	BIT(3)
> +#define MIPI_PHY_A7_DOMAIN	BIT(2)
> +
> +#define GPC_PU_PGC_SW_PUP_REQ	0xf8
> +#define GPC_PU_PGC_SW_PDN_REQ	0x104
> +#define USB_HSIC_PHY_SW_Pxx_REQ	BIT(4)
> +#define USB_OTG2_PHY_SW_Pxx_REQ	BIT(3)
> +#define USB_OTG1_PHY_SW_Pxx_REQ	BIT(2)
> +#define PCIE_PHY_SW_Pxx_REQ	BIT(1)
> +#define MIPI_PHY_SW_Pxx_REQ	BIT(0)
> +

After apply, what i see is:
#define GPC_PU_PGC_SW_PUP_REQ   0xf8
#define GPC_PU_PGC_SW_PDN_REQ   0x104
#define USB_HSIC_PHY_SW_Pxx_REQ BIT(4)
#define USB_OTG2_PHY_SW_Pxx_REQ BIT(3)
#define USB_OTG1_PHY_SW_Pxx_REQ BIT(2)
#define PCIE_PHY_SW_Pxx_REQ     BIT(1)
#define MIPI_PHY_SW_Pxx_REQ     BIT(0)

Looks quite tight,
Can we have one more TAB for the definition?
Like:
#define GPC_PU_PGC_SW_PUP_REQ 		0xf8

> +#define GPC_MAX_REGISTER	0x1000
> +
> +#define GPC_PGC_nCTRL_PCR	BIT(0)
> +
> +struct imx7_pgc_domain {
> +	struct generic_pm_domain genpd;
> +	struct regmap *regmap;
> +	struct regulator *regulator;
> +
> +	unsigned int pgc_nctrl;
> +
> +	const struct {
> +		u32 pxx;
> +		u32 map;
> +	} bits;
> +
> +	const int voltage;
> +	struct device *dev;
> +};
> +
> +static int imx7_gpc_pu_pgc_sw_pxx_req(struct generic_pm_domain *genpd,
> +				      bool on)
> +{
> +	struct imx7_pgc_domain *domain = container_of(genpd,
> +						      struct imx7_pgc_domain,
> +						      genpd);
> +	unsigned int offset = on ?
> +		GPC_PU_PGC_SW_PUP_REQ : GPC_PU_PGC_SW_PDN_REQ;
> +	const bool enable_power_control = domain->pgc_nctrl && !on;
> +	const bool has_regulator = !IS_ERR(domain->regulator);
> +	unsigned long deadline;
> +	int ret = 0;
> +
> +	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
> +			   domain->bits.map, domain->bits.map);
> +
> +	if (has_regulator && on) {
> +		ret = regulator_enable(domain->regulator);
> +		if (ret) {
> +			dev_err(domain->dev, "failed to enable regulator\n");
> +			goto unmap;
> +		}
> +	}
> +
> +	if (enable_power_control)
> +		regmap_update_bits(domain->regmap, domain->pgc_nctrl,
> +				   GPC_PGC_nCTRL_PCR, GPC_PGC_nCTRL_PCR);
> +
> +	regmap_update_bits(domain->regmap, offset,
> +			   domain->bits.pxx, domain->bits.pxx);
> +
> +	/*
> +	 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
> +	 * for PUP_REQ/PDN_REQ bit to be cleared
> +	 */
> +	deadline = jiffies + msecs_to_jiffies(1);
> +	while (true) {
> +		u32 pxx_req;
> +
> +		regmap_read(domain->regmap, offset, &pxx_req);
> +
> +		if (!(pxx_req & domain->bits.pxx))
> +			break;
> +
> +		if (time_after(jiffies, deadline)) {
> +			dev_err(domain->dev, "falied to command PGC\n");
> +			ret = -ETIMEDOUT;
> +			/*
> +			 * If we were in a process of enabling a
> +			 * domain and failed we might as well disable
> +			 * the regulator we just enabled. And if it
> +			 * was the opposite situation and we failed to
> +			 * power down -- keep the regulator on
> +			 */
> +			on = !on;
> +			break;
> +		}
> +
> +		cpu_relax();
> +	}
> +
> +	if (enable_power_control)
> +		regmap_update_bits(domain->regmap, domain->pgc_nctrl,
> +				   GPC_PGC_nCTRL_PCR, 0);
> +
> +	if (has_regulator && !on) {
> +		int err;
> +
> +		err = regulator_disable(domain->regulator);
> +		if (err)
> +			dev_err(domain->dev,
> +				"failed to disable regulator: %d\n", ret);
> +		/* Preserve earlier error code */
> +		ret = ret ?: err;
> +	}
> +unmap:
> +	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
> +			   domain->bits.map, 0);
> +	return ret;
> +}
> +
> +static int imx7_gpc_pu_pgc_sw_pup_req(struct generic_pm_domain *genpd)
> +{
> +	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, true);
> +}
> +
> +static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
> +{
> +	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
> +}
> +
> +static struct imx7_pgc_domain imx7_pgc_domains[] = {
> +	[IMX7_POWER_DOMAIN_USB_HSIC_PHY] = {
> +		.genpd = {
> +			.name      = "usb-hsic-phy",
> +		},
> +		.bits  = {
> +			.pxx = USB_HSIC_PHY_SW_Pxx_REQ,
> +			.map = USB_HSIC_PHY_A7_DOMAIN,
> +		},
> +		.voltage   = 1200000,
> +		.pgc_nctrl = 0x0d00,
> +	},
> +
> +	[IMX7_POWER_DOMAIN_USB_OTG2_PHY] = {
> +		.genpd = {
> +			.name      = "usb-otg2-phy",
> +		},
> +		.bits  = {
> +			.pxx = USB_OTG2_PHY_SW_Pxx_REQ,
> +			.map = USB_OTG2_PHY_A7_DOMAIN,
> +		},
> +	},
> +
> +	[IMX7_POWER_DOMAIN_USB_OTG1_PHY] = {
> +		.genpd = {
> +			.name      = "usb-otg1-phy",
> +		},
> +		.bits  = {
> +			.pxx = USB_OTG1_PHY_SW_Pxx_REQ,
> +			.map = USB_OTG1_PHY_A7_DOMAIN,
> +		},
> +	},
> +
> +	[IMX7_POWER_DOMAIN_PCIE_PHY] = {
> +		.genpd = {
> +			.name      = "pcie-phy",
> +		},
> +		.bits  = {
> +			.pxx = PCIE_PHY_SW_Pxx_REQ,
> +			.map = PCIE_PHY_A7_DOMAIN,
> +		},
> +		.voltage   = 1000000,
> +		.pgc_nctrl = 0x0c40,
> +	},
> +
> +	[IMX7_POWER_DOMAIN_MIPI_PHY] = {
> +		.genpd = {
> +			.name      = "mipi-phy",
> +		},
> +		.bits  = {
> +			.pxx = MIPI_PHY_SW_Pxx_REQ,
> +			.map = MIPI_PHY_A7_DOMAIN,
> +		},
> +		.voltage   = 1000000,
> +		.pgc_nctrl = 0x0c00,
> +	},
> +};
> +
> +static int imx7_pgc_domain_probe(struct platform_device *pdev)
> +{
> +	struct imx7_pgc_domain *domain = pdev->dev.platform_data;
> +	int ret;
> +
> +	domain->dev = &pdev->dev;
> +
> +	ret = pm_genpd_init(&domain->genpd, NULL, true);
> +	if (ret) {
> +		dev_err(domain->dev, "Failed to init power domain\n");
> +		return ret;
> +	}
> +
> +	domain->regulator = devm_regulator_get_optional(domain->dev, "power");
> +	if (IS_ERR(domain->regulator) &&
> +	    PTR_ERR(domain->regulator) != -ENODEV) {
> +		dev_err(domain->dev, "Failed to get domain's regulator\n");
> +		return PTR_ERR(domain->regulator);
> +	}
> +
> +	if (!IS_ERR(domain->regulator)) {
> +		if (!domain->voltage) {
> +			WARN(1, "No voltage configured for domain's regulator");
> +			return -EINVAL;
> +		}
> +
> +		regulator_set_voltage(domain->regulator,
> +				      domain->voltage, domain->voltage);
> +	}
> +
> +	ret = of_genpd_add_provider_simple(domain->dev->of_node,
> +					   &domain->genpd);
> +	if (ret) {
> +		dev_err(domain->dev, "Failed to add genpd provider\n");
> +		pm_genpd_remove(&domain->genpd);
> +	}
> +
> +	return ret;
> +}
> +
> +static int imx7_pgc_domain_remove(struct platform_device *pdev)
> +{
> +	struct imx7_pgc_domain *domain = pdev->dev.platform_data;
> +
> +	of_genpd_del_provider(domain->dev->of_node);
> +	pm_genpd_remove(&domain->genpd);
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id imx7_pgc_domain_id[] = {
> +	{ "imx7-pgc-domain", },
> +	{ },
> +};
> +
> +static struct platform_driver imx7_pgc_domain_driver = {
> +	.driver = {
> +		.name = "imx7-pgc",
> +	},
> +	.probe    = imx7_pgc_domain_probe,
> +	.remove   = imx7_pgc_domain_remove,
> +	.id_table = imx7_pgc_domain_id,
> +};
> +builtin_platform_driver(imx7_pgc_domain_driver)

Again, i have a fundamental question about this patch implementation
that why we choose above way to register the power domain?

I'm sorry that i did not know too much history.
Would you guys please help share some information?

Because AFAIK this way will register each domain as a power domain
provider which is a bit violate the real HW and current power domain
framework design. And it is a bit more complicated to use than before.

IMHO i would rather prefer the old traditional and simpler way that one
provider (GPC) supplies multiple domains (PCIE/MIPI/HSIC PHY domain)
than this patch does.

However, i might be wrong. Please help to clear.

> +
> +static int imx_gpcv2_probe(struct platform_device *pdev)
> +{
> +	static const struct regmap_config regmap_config = {
> +		.cache_type	= REGCACHE_NONE,

You could drop it as GPC does.

> +		.reg_bits	= 32,
> +		.val_bits	= 32,
> +		.reg_stride	= 4,
> +		.max_register	= GPC_MAX_REGISTER,

Do you need add some readable/writeable reg?

There seems to be some reserved regs in your range.
I can easily got the below crash:

root@imx6ul7d:/sys/kernel/debug/regmap/303a0000.gpc# cat registers 
[   54.985395] Unhandled fault: external abort on non-linefetch (0x1008) at 0xf08511c0
[   54.993166] pgd = ed02c000
[   54.995894] [f08511c0] *pgd=af00c811, *pte=303a0653, *ppte=303a0453
[   55.002215] Internal error: : 1008 [#1] SMP ARM
[   55.006756] Modules linked in:
[   55.009830] CPU: 0 PID: 750 Comm: cat Not tainted 4.11.0-rc1-00057-g2d60158-dirty #1169
[   55.017842] Hardware name: Freescale i.MX7 Dual (Device Tree)
[   55.023598] task: ee20ee40 task.stack: ed0f8000
[   55.028146] PC is at regmap_mmio_read32le+0x14/0x24
[   55.033035] LR is at regmap_mmio_read+0x40/0x60
[   55.037577] pc : [<c054f160>]    lr : [<c054f348>]    psr: 20070093
[   55.037577] sp : ed0f9dc8  ip : ed0f9dd8  fp : ed0f9dd4
[   55.049064] r10: ed160000  r9 : ef341000  r8 : ed0f9f80
[   55.054299] r7 : ed0f9e5c  r6 : ed0f9e5c  r5 : 000001c0  r4 : ef3bb900
[   55.060836] r3 : f0851000  r2 : ed0f9e5c  r1 : f08511c0  r0 : ef3bb900
[   55.067374] Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
[   55.074606] Control: 10c5387d  Table: ad02c06a  DAC: 00000051
[   55.080361] Process cat (pid: 750, stack limit = 0xed0f8210)
....

> +	};
> +	struct device *dev = &pdev->dev;
> +	struct device_node *pgc_np, *np;
> +	struct regmap *regmap;
> +	struct resource *res;
> +	void __iomem *base;
> +	int ret;
> +
> +	pgc_np = of_get_child_by_name(dev->of_node, "pgc");
> +	if (!pgc_np) {
> +		dev_err(dev, "No power domains specified in DT\n");
> +		return -EINVAL;
> +	}
> +
> +	res  = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	regmap = devm_regmap_init_mmio(dev, base, &regmap_config);
> +	if (IS_ERR(regmap)) {
> +		ret = PTR_ERR(regmap);
> +		dev_err(dev, "failed to init regmap (%d)\n", ret);
> +		return ret;
> +	}
> +
> +	for_each_child_of_node(pgc_np, np) {
> +		struct platform_device *pd_pdev;
> +		struct imx7_pgc_domain *domain;
> +		u32 domain_index;
> +
> +		ret = of_property_read_u32(np, "reg", &domain_index);
> +		if (ret) {
> +			dev_err(dev, "Failed to read 'reg' property\n");
> +			of_node_put(np);
> +			return ret;
> +		}
> +
> +		if (domain_index >= ARRAY_SIZE(imx7_pgc_domains)) {
> +			dev_warn(dev,
> +				 "Domain index %d is out of bounds\n",
> +				 domain_index);
> +			continue;
> +		}
> +
> +		domain = &imx7_pgc_domains[domain_index];
> +		domain->regmap = regmap;
> +		domain->genpd.power_on  = imx7_gpc_pu_pgc_sw_pup_req;
> +		domain->genpd.power_off = imx7_gpc_pu_pgc_sw_pdn_req;
> +
> +		pd_pdev = platform_device_alloc("imx7-pgc-domain",
> +						domain_index);
> +		if (!pd_pdev) {
> +			dev_err(dev, "Failed to allocate platform device\n");
> +			of_node_put(np);
> +			return -ENOMEM;
> +		}
> +
> +		pd_pdev->dev.platform_data = domain;
> +		pd_pdev->dev.parent = dev;
> +		pd_pdev->dev.of_node = np;
> +
> +		ret = platform_device_add(pd_pdev);
> +		if (ret) {
> +			platform_device_put(pd_pdev);
> +			of_node_put(np);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id imx_gpcv2_dt_ids[] = {
> +	{ .compatible = "fsl,imx7d-gpc" },
> +	{ }
> +};
> +
> +static struct platform_driver imx_gpc_driver = {
> +	.driver = {
> +		.name = "imx-gpcv2",
> +		.of_match_table = imx_gpcv2_dt_ids,
> +	},
> +	.probe = imx_gpcv2_probe,
> +};
> +builtin_platform_driver(imx_gpc_driver)
> -- 
> 2.9.3
> 

Regards
Dong Aisheng

Andrey Smirnov March 27, 2017, 6:42 p.m. UTC | #3

On Thu, Mar 23, 2017 at 11:24 PM, Dong Aisheng <[e-mail]> wrote:
> On Tue, Mar 21, 2017 at 07:50:04AM -0700, Andrey Smirnov wrote:
>> Add code allowing for control of various power domains managed by GPCv2
>> IP block found in i.MX7 series of SoCs. Power domains covered by this
>> patch are:
>>
>>     - PCIE PHY
>>     - MIPI PHY
>>     - USB HSIC PHY
>>     - USB OTG1/2 PHY
>>
>
> You probably may need drop USB OTG which is not claimed in current RM.
> See the PGC definition in 5.5.10 GPC Memory Map section.
>
> Each PGC (CPU type, MIX type, PU type) will occupy 64 Bytes address space,
> the specific base address of each PGC are listed as below.
> • 0x800 ~ 0x83F : PGC for A7 core0
> • 0x840 ~ 0x87F: PGC for A7 core1
> • 0x880 ~ 0x8BF: PGC for A7 SCU
> • 0xA00 ~ 0xA3F: PGC for fastmix/megamix
> • 0xC00 ~ 0xC3F: PGC for MIPI PHY
> • 0xC40 ~ 0xC7F: PGC for PCIE_PHY
> • 0xC80 ~ 0xCBF: Reserved
> • 0xCC0 ~ 0xCFF: Reserved
> • 0xD00 ~ 0xD3F: PGC for USB HSIC PHY
>
> And in 5.4 Power Management Unit (PMU) chapter,
> you will find the USB OTG phy power is directly supplied by
> VDD_USB_OTG1_3P3_IN/VDD_USB_OTG2_3P3_IN.
>
> http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX7DRM.pdf
>
> I understand that there's also some USB OTG code exist in NXP internal
> tree, but that's legacy for early doc implementation and may be deprecated.
> so i assume it should be gone.
>
> Hopefully i will double confirm with our IC designer tomorrow.
>

USB OTG domains are absent from that list, true, but they are
mentioned all of the place further in that section in register map
documentation, which makes it difficult to tell which part of the
datasheet is not up to date.

I'm going to drop those power domains for now, since I don't have a
use-case for them and it would also allow me to get rid of the chunk
of code you thought was messy. However it would be nice to get an
updated version of RM where all of that is straightened out.


>> Support for any other power domain controlled by GPC is not present, and
>> can be added at some later point.
>>
>> Testing of this code was done against a PCIe driver.
>>
>> Cc: [e-mail]
>> Cc: Lucas Stach <[e-mail]>
>> Cc: Fabio Estevam <[e-mail]>
>> Cc: Dong Aisheng <[e-mail]>
>> Cc: [e-mail]
>> Cc: [e-mail]
>> Signed-off-by: Andrey Smirnov <[e-mail]>
>> ---
>>  drivers/soc/Kconfig      |   1 +
>>  drivers/soc/imx/Kconfig  |  10 ++
>>  drivers/soc/imx/Makefile |   1 +
>>  drivers/soc/imx/gpcv2.c  | 365 +++++++++++++++++++++++++++++++++++++++++++++++
>>  4 files changed, 377 insertions(+)
>>  create mode 100644 drivers/soc/imx/Kconfig
>>  create mode 100644 drivers/soc/imx/gpcv2.c
>>
>> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
>> index f09023f..8943543 100644
>> --- a/drivers/soc/Kconfig
>> +++ b/drivers/soc/Kconfig
>> @@ -2,6 +2,7 @@ menu "SOC (System On Chip) specific Drivers"
>>
>>  source "drivers/soc/bcm/Kconfig"
>>  source "drivers/soc/fsl/Kconfig"
>> +source "drivers/soc/imx/Kconfig"
>>  source "drivers/soc/mediatek/Kconfig"
>>  source "drivers/soc/qcom/Kconfig"
>>  source "drivers/soc/rockchip/Kconfig"
>> diff --git a/drivers/soc/imx/Kconfig b/drivers/soc/imx/Kconfig
>> new file mode 100644
>> index 0000000..bc7f0ee0
>> --- /dev/null
>> +++ b/drivers/soc/imx/Kconfig
>> @@ -0,0 +1,10 @@
>> +menu "i.MX SoC drivers"
>> +
>> +config IMX7_PM_DOMAINS
>> +     bool "i.MX7 PM domains"
>> +     select PM_GENERIC_DOMAINS
>> +     depends on SOC_IMX7D || (COMPILE_TEST && OF)
>> +     default y if SOC_IMX7D
>> +
>> +endmenu
>> +
>> diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
>> index 35861f5..5b6e396 100644
>> --- a/drivers/soc/imx/Makefile
>> +++ b/drivers/soc/imx/Makefile
>> @@ -1 +1,2 @@
>>  obj-y += gpc.o
>> +obj-$(CONFIG_IMX7_PM_DOMAINS) += gpcv2.o
>> diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
>> new file mode 100644
>> index 0000000..a27c5f8
>> --- /dev/null
>> +++ b/drivers/soc/imx/gpcv2.c
>> @@ -0,0 +1,365 @@
>> +/*
>> + * Copyright 2017 Impinj, Inc
>> + * Author: Andrey Smirnov <[e-mail]>
>> + *
>> + * Based on the code of analogus driver:
>> + *
>> + * Copyright 2015-2017 Pengutronix, Lucas Stach <[e-mail]>
>> + *
>> + * The code contained herein is licensed under the GNU General Public
>> + * License. You may obtain a copy of the GNU General Public License
>> + * Version 2 or later at the following locations:
>> + *
>> + * http://www.opensource.org/licenses/gpl-license.html
>> + * http://www.gnu.org/copyleft/gpl.html
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_domain.h>
>> +#include <linux/regmap.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <dt-bindings/power/imx7-power.h>
>> +
>> +#define GPC_PGC_CPU_MAPPING  0xec
>> +#define USB_HSIC_PHY_A7_DOMAIN       BIT(6)
>> +#define USB_OTG2_PHY_A7_DOMAIN       BIT(5)
>> +#define USB_OTG1_PHY_A7_DOMAIN       BIT(4)
>> +#define PCIE_PHY_A7_DOMAIN   BIT(3)
>> +#define MIPI_PHY_A7_DOMAIN   BIT(2)
>> +
>> +#define GPC_PU_PGC_SW_PUP_REQ        0xf8
>> +#define GPC_PU_PGC_SW_PDN_REQ        0x104
>> +#define USB_HSIC_PHY_SW_Pxx_REQ      BIT(4)
>> +#define USB_OTG2_PHY_SW_Pxx_REQ      BIT(3)
>> +#define USB_OTG1_PHY_SW_Pxx_REQ      BIT(2)
>> +#define PCIE_PHY_SW_Pxx_REQ  BIT(1)
>> +#define MIPI_PHY_SW_Pxx_REQ  BIT(0)
>> +
>
> After apply, what i see is:
> #define GPC_PU_PGC_SW_PUP_REQ   0xf8
> #define GPC_PU_PGC_SW_PDN_REQ   0x104
> #define USB_HSIC_PHY_SW_Pxx_REQ BIT(4)
> #define USB_OTG2_PHY_SW_Pxx_REQ BIT(3)
> #define USB_OTG1_PHY_SW_Pxx_REQ BIT(2)
> #define PCIE_PHY_SW_Pxx_REQ     BIT(1)
> #define MIPI_PHY_SW_Pxx_REQ     BIT(0)
>
> Looks quite tight,
> Can we have one more TAB for the definition?
> Like:
> #define GPC_PU_PGC_SW_PUP_REQ           0xf8
>

Sure, will do.

>> +#define GPC_MAX_REGISTER     0x1000
>> +
>> +#define GPC_PGC_nCTRL_PCR    BIT(0)
>> +
>> +struct imx7_pgc_domain {
>> +     struct generic_pm_domain genpd;
>> +     struct regmap *regmap;
>> +     struct regulator *regulator;
>> +
>> +     unsigned int pgc_nctrl;
>> +
>> +     const struct {
>> +             u32 pxx;
>> +             u32 map;
>> +     } bits;
>> +
>> +     const int voltage;
>> +     struct device *dev;
>> +};
>> +
>> +static int imx7_gpc_pu_pgc_sw_pxx_req(struct generic_pm_domain *genpd,
>> +                                   bool on)
>> +{
>> +     struct imx7_pgc_domain *domain = container_of(genpd,
>> +                                                   struct imx7_pgc_domain,
>> +                                                   genpd);
>> +     unsigned int offset = on ?
>> +             GPC_PU_PGC_SW_PUP_REQ : GPC_PU_PGC_SW_PDN_REQ;
>> +     const bool enable_power_control = domain->pgc_nctrl && !on;
>> +     const bool has_regulator = !IS_ERR(domain->regulator);
>> +     unsigned long deadline;
>> +     int ret = 0;
>> +
>> +     regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
>> +                        domain->bits.map, domain->bits.map);
>> +
>> +     if (has_regulator && on) {
>> +             ret = regulator_enable(domain->regulator);
>> +             if (ret) {
>> +                     dev_err(domain->dev, "failed to enable regulator\n");
>> +                     goto unmap;
>> +             }
>> +     }
>> +
>> +     if (enable_power_control)
>> +             regmap_update_bits(domain->regmap, domain->pgc_nctrl,
>> +                                GPC_PGC_nCTRL_PCR, GPC_PGC_nCTRL_PCR);
>> +
>> +     regmap_update_bits(domain->regmap, offset,
>> +                        domain->bits.pxx, domain->bits.pxx);
>> +
>> +     /*
>> +      * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
>> +      * for PUP_REQ/PDN_REQ bit to be cleared
>> +      */
>> +     deadline = jiffies + msecs_to_jiffies(1);
>> +     while (true) {
>> +             u32 pxx_req;
>> +
>> +             regmap_read(domain->regmap, offset, &pxx_req);
>> +
>> +             if (!(pxx_req & domain->bits.pxx))
>> +                     break;
>> +
>> +             if (time_after(jiffies, deadline)) {
>> +                     dev_err(domain->dev, "falied to command PGC\n");
>> +                     ret = -ETIMEDOUT;
>> +                     /*
>> +                      * If we were in a process of enabling a
>> +                      * domain and failed we might as well disable
>> +                      * the regulator we just enabled. And if it
>> +                      * was the opposite situation and we failed to
>> +                      * power down -- keep the regulator on
>> +                      */
>> +                     on = !on;
>> +                     break;
>> +             }
>> +
>> +             cpu_relax();
>> +     }
>> +
>> +     if (enable_power_control)
>> +             regmap_update_bits(domain->regmap, domain->pgc_nctrl,
>> +                                GPC_PGC_nCTRL_PCR, 0);
>> +
>> +     if (has_regulator && !on) {
>> +             int err;
>> +
>> +             err = regulator_disable(domain->regulator);
>> +             if (err)
>> +                     dev_err(domain->dev,
>> +                             "failed to disable regulator: %d\n", ret);
>> +             /* Preserve earlier error code */
>> +             ret = ret ?: err;
>> +     }
>> +unmap:
>> +     regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
>> +                        domain->bits.map, 0);
>> +     return ret;
>> +}
>> +
>> +static int imx7_gpc_pu_pgc_sw_pup_req(struct generic_pm_domain *genpd)
>> +{
>> +     return imx7_gpc_pu_pgc_sw_pxx_req(genpd, true);
>> +}
>> +
>> +static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
>> +{
>> +     return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
>> +}
>> +
>> +static struct imx7_pgc_domain imx7_pgc_domains[] = {
>> +     [IMX7_POWER_DOMAIN_USB_HSIC_PHY] = {
>> +             .genpd = {
>> +                     .name      = "usb-hsic-phy",
>> +             },
>> +             .bits  = {
>> +                     .pxx = USB_HSIC_PHY_SW_Pxx_REQ,
>> +                     .map = USB_HSIC_PHY_A7_DOMAIN,
>> +             },
>> +             .voltage   = 1200000,
>> +             .pgc_nctrl = 0x0d00,
>> +     },
>> +
>> +     [IMX7_POWER_DOMAIN_USB_OTG2_PHY] = {
>> +             .genpd = {
>> +                     .name      = "usb-otg2-phy",
>> +             },
>> +             .bits  = {
>> +                     .pxx = USB_OTG2_PHY_SW_Pxx_REQ,
>> +                     .map = USB_OTG2_PHY_A7_DOMAIN,
>> +             },
>> +     },
>> +
>> +     [IMX7_POWER_DOMAIN_USB_OTG1_PHY] = {
>> +             .genpd = {
>> +                     .name      = "usb-otg1-phy",
>> +             },
>> +             .bits  = {
>> +                     .pxx = USB_OTG1_PHY_SW_Pxx_REQ,
>> +                     .map = USB_OTG1_PHY_A7_DOMAIN,
>> +             },
>> +     },
>> +
>> +     [IMX7_POWER_DOMAIN_PCIE_PHY] = {
>> +             .genpd = {
>> +                     .name      = "pcie-phy",
>> +             },
>> +             .bits  = {
>> +                     .pxx = PCIE_PHY_SW_Pxx_REQ,
>> +                     .map = PCIE_PHY_A7_DOMAIN,
>> +             },
>> +             .voltage   = 1000000,
>> +             .pgc_nctrl = 0x0c40,
>> +     },
>> +
>> +     [IMX7_POWER_DOMAIN_MIPI_PHY] = {
>> +             .genpd = {
>> +                     .name      = "mipi-phy",
>> +             },
>> +             .bits  = {
>> +                     .pxx = MIPI_PHY_SW_Pxx_REQ,
>> +                     .map = MIPI_PHY_A7_DOMAIN,
>> +             },
>> +             .voltage   = 1000000,
>> +             .pgc_nctrl = 0x0c00,
>> +     },
>> +};
>> +
>> +static int imx7_pgc_domain_probe(struct platform_device *pdev)
>> +{
>> +     struct imx7_pgc_domain *domain = pdev->dev.platform_data;
>> +     int ret;
>> +
>> +     domain->dev = &pdev->dev;
>> +
>> +     ret = pm_genpd_init(&domain->genpd, NULL, true);
>> +     if (ret) {
>> +             dev_err(domain->dev, "Failed to init power domain\n");
>> +             return ret;
>> +     }
>> +
>> +     domain->regulator = devm_regulator_get_optional(domain->dev, "power");
>> +     if (IS_ERR(domain->regulator) &&
>> +         PTR_ERR(domain->regulator) != -ENODEV) {
>> +             dev_err(domain->dev, "Failed to get domain's regulator\n");
>> +             return PTR_ERR(domain->regulator);
>> +     }
>> +
>> +     if (!IS_ERR(domain->regulator)) {
>> +             if (!domain->voltage) {
>> +                     WARN(1, "No voltage configured for domain's regulator");
>> +                     return -EINVAL;
>> +             }
>> +
>> +             regulator_set_voltage(domain->regulator,
>> +                                   domain->voltage, domain->voltage);
>> +     }
>> +
>> +     ret = of_genpd_add_provider_simple(domain->dev->of_node,
>> +                                        &domain->genpd);
>> +     if (ret) {
>> +             dev_err(domain->dev, "Failed to add genpd provider\n");
>> +             pm_genpd_remove(&domain->genpd);
>> +     }
>> +
>> +     return ret;
>> +}
>> +
>> +static int imx7_pgc_domain_remove(struct platform_device *pdev)
>> +{
>> +     struct imx7_pgc_domain *domain = pdev->dev.platform_data;
>> +
>> +     of_genpd_del_provider(domain->dev->of_node);
>> +     pm_genpd_remove(&domain->genpd);
>> +
>> +     return 0;
>> +}
>> +
>> +static const struct platform_device_id imx7_pgc_domain_id[] = {
>> +     { "imx7-pgc-domain", },
>> +     { },
>> +};
>> +
>> +static struct platform_driver imx7_pgc_domain_driver = {
>> +     .driver = {
>> +             .name = "imx7-pgc",
>> +     },
>> +     .probe    = imx7_pgc_domain_probe,
>> +     .remove   = imx7_pgc_domain_remove,
>> +     .id_table = imx7_pgc_domain_id,
>> +};
>> +builtin_platform_driver(imx7_pgc_domain_driver)
>
> Again, i have a fundamental question about this patch implementation
> that why we choose above way to register the power domain?
>
> I'm sorry that i did not know too much history.
> Would you guys please help share some information?
>
> Because AFAIK this way will register each domain as a power domain
> provider which is a bit violate the real HW and current power domain
> framework design. And it is a bit more complicated to use than before.
>
> IMHO i would rather prefer the old traditional and simpler way that one
> provider (GPC) supplies multiple domains (PCIE/MIPI/HSIC PHY domain)
> than this patch does.
>
> However, i might be wrong. Please help to clear.
>
>> +
>> +static int imx_gpcv2_probe(struct platform_device *pdev)
>> +{
>> +     static const struct regmap_config regmap_config = {
>> +             .cache_type     = REGCACHE_NONE,
>
> You could drop it as GPC does.
>

Yep, will remove.

>> +             .reg_bits       = 32,
>> +             .val_bits       = 32,
>> +             .reg_stride     = 4,
>> +             .max_register   = GPC_MAX_REGISTER,
>
> Do you need add some readable/writeable reg?
>
> There seems to be some reserved regs in your range.
> I can easily got the below crash:
>
> root@imx6ul7d:/sys/kernel/debug/regmap/303a0000.gpc# cat registers
> [   54.985395] Unhandled fault: external abort on non-linefetch (0x1008) at 0xf08511c0
> [   54.993166] pgd = ed02c000
> [   54.995894] [f08511c0] *pgd=af00c811, *pte=303a0653, *ppte=303a0453
> [   55.002215] Internal error: : 1008 [#1] SMP ARM
> [   55.006756] Modules linked in:
> [   55.009830] CPU: 0 PID: 750 Comm: cat Not tainted 4.11.0-rc1-00057-g2d60158-dirty #1169
> [   55.017842] Hardware name: Freescale i.MX7 Dual (Device Tree)
> [   55.023598] task: ee20ee40 task.stack: ed0f8000
> [   55.028146] PC is at regmap_mmio_read32le+0x14/0x24
> [   55.033035] LR is at regmap_mmio_read+0x40/0x60
> [   55.037577] pc : [<c054f160>]    lr : [<c054f348>]    psr: 20070093
> [   55.037577] sp : ed0f9dc8  ip : ed0f9dd8  fp : ed0f9dd4
> [   55.049064] r10: ed160000  r9 : ef341000  r8 : ed0f9f80
> [   55.054299] r7 : ed0f9e5c  r6 : ed0f9e5c  r5 : 000001c0  r4 : ef3bb900
> [   55.060836] r3 : f0851000  r2 : ed0f9e5c  r1 : f08511c0  r0 : ef3bb900
> [   55.067374] Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
> [   55.074606] Control: 10c5387d  Table: ad02c06a  DAC: 00000051
> [   55.080361] Process cat (pid: 750, stack limit = 0xed0f8210)
> ....

Good catch, thank you! I'll update the code to make sure this doesn't happen.

Thanks,
Andrey Smirnov

Lucas Stach March 29, 2017, 4:08 p.m. UTC | #4

Hi Dong,

Am Donnerstag, den 30.03.2017, 15:51 +0800 schrieb Dong Aisheng:
> Hi Lucas,
> 
> On Thu, Mar 23, 2017 at 03:35:49PM +0100, Lucas Stach wrote:
> > Hi Dong,
> > 
> > Am Freitag, den 24.03.2017, 14:24 +0800 schrieb Dong Aisheng:
> > [...]
> > > > +static struct platform_driver imx7_pgc_domain_driver = {
> > > > +	.driver = {
> > > > +		.name = "imx7-pgc",
> > > > +	},
> > > > +	.probe    = imx7_pgc_domain_probe,
> > > > +	.remove   = imx7_pgc_domain_remove,
> > > > +	.id_table = imx7_pgc_domain_id,
> > > > +};
> > > > +builtin_platform_driver(imx7_pgc_domain_driver)
> > > 
> > > Again, i have a fundamental question about this patch implementation
> > > that why we choose above way to register the power domain?
> > > 
> > > I'm sorry that i did not know too much history.
> > > Would you guys please help share some information?
> > > 
> > > Because AFAIK this way will register each domain as a power domain
> > > provider which is a bit violate the real HW and current power domain
> > > framework design. And it is a bit more complicated to use than before.
> > > 
> > > IMHO i would rather prefer the old traditional and simpler way that one
> > > provider (GPC) supplies multiple domains (PCIE/MIPI/HSIC PHY domain)
> > > than this patch does.
> > > 
> > > However, i might be wrong. Please help to clear.
> > 
> > This way we can properly describe each power domain with the regulator
> > supplying the domain and the clocks of the devices inside the domain in
> > the device tree.
> > 
> 
> Thanks for the explaination. I understand that purpose.
> 
> Now my concern is why we doing things like this:
> Builtin two platforms driver and use one to dynamically create
> device to trigger another driver bind to register the domain.
> 
> static int imx7_pgc_domain_probe(struct platform_device *pdev)
> {
>         of_genpd_add_provider_simple(domain->dev->of_node,
>                                            &domain->genpd);
> }
> 
> static struct platform_driver imx7_pgc_domain_driver = {
>         .driver = {
>                 .name = "imx7-pgc",
>         },
>         .probe    = imx7_pgc_domain_probe,
> };
> builtin_platform_driver(imx7_pgc_domain_driver)
> 
> 
> static int imx_gpcv2_probe(struct platform_device *pdev)
> {
> 
>         for_each_child_of_node(pgc_np, np) {
>                 pd_pdev = platform_device_alloc("imx7-pgc-domain",
>                                                 domain_index);
>                 ret = platform_device_add(pd_pdev);
> 	}
> }
> 
> static struct platform_driver imx_gpc_driver = {
>         .driver = {
>                 .name = "imx-gpcv2",
>                 .of_match_table = imx_gpcv2_dt_ids,
>         }, 
>         .probe = imx_gpcv2_probe,
> };
> builtin_platform_driver(imx_gpc_driver)
> 
> Is there any special purpose or i missed something?

Yes, clocks and regulators can be looked up by the devices attached to
the DT nodes. This makes handling of those easy (or at all possible, the
regulator API doesn't allow to get regulators without the proper devnode
attached to a DT node).

> Can we just use one or a simple core_initcall(imx_gpcv2_probe) cause
> this probably should be registered early for other consumers?

Initcall levels are not going to work. We are dealing with regulators,
which can have supplies that are only probed when other modules are
loaded. If we need the domains to be up before the consumers, the only
way to deal with that is to select CONFIG_PM and
CONFIG_PM_GENERIC_DOMAINS from the platform, so we have proper probe
defer handling for consumer devices of the power domains.

> Personally i'd be more like Rockchip's power domain implementation.

Why?

> See:
> arch/arm/boot/dts/rk3288.dtsi
> drivers/soc/rockchip/pm_domains.c
> Dcumentation/devicetree/bindings/soc/rockchip/power_domain.txt
> 
> How about refer to the Rockchip's way?

Why? We just changed the way how it's done for GPCv1, after more than 1
year of those patches being on the list. Why should we do it differently
for GPCv2?

> 
> Then it could also address our issues and the binding would be
> still like:
> gpc: gpc@303a0000 {
>         compatible = "fsl,imx7d-gpc";
>         reg = <0x303a0000 0x1000>;
>         interrupt-controller;
>         interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
>         #interrupt-cells = <3>;
>         interrupt-parent = <&intc>;
> 
>         pgc {
>                 #address-cells = <1>;
>                 #size-cells = <0>;
> 
>                 pgc_pcie_phy: power-domain@IMX7_POWER_DOMAIN_PCIE_PHY {
>                         reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
>                         power-supply = <&reg_1p0d>;
> 			clocks = <xxx>;
>                 };
> 
> 		....
>         };
> };
> 
> It also drops #power-domain-cells and register domain by
> one provider with multi domains which is more align with HW.
> 
> How do you think of it?

How is this more aligned with the hardware? Both options are an
arbitrary abstraction chosen in the DT binding.

Regards,
Lucas

Dong Aisheng March 30, 2017, 6:58 a.m. UTC | #5

On Mon, Mar 27, 2017 at 11:42:15AM -0700, Andrey Smirnov wrote:
> On Thu, Mar 23, 2017 at 11:24 PM, Dong Aisheng <[e-mail]> wrote:
> > On Tue, Mar 21, 2017 at 07:50:04AM -0700, Andrey Smirnov wrote:
> >> Add code allowing for control of various power domains managed by GPCv2
> >> IP block found in i.MX7 series of SoCs. Power domains covered by this
> >> patch are:
> >>
> >>     - PCIE PHY
> >>     - MIPI PHY
> >>     - USB HSIC PHY
> >>     - USB OTG1/2 PHY
> >>
> >
> > You probably may need drop USB OTG which is not claimed in current RM.
> > See the PGC definition in 5.5.10 GPC Memory Map section.
> >
> > Each PGC (CPU type, MIX type, PU type) will occupy 64 Bytes address space,
> > the specific base address of each PGC are listed as below.
> > • 0x800 ~ 0x83F : PGC for A7 core0
> > • 0x840 ~ 0x87F: PGC for A7 core1
> > • 0x880 ~ 0x8BF: PGC for A7 SCU
> > • 0xA00 ~ 0xA3F: PGC for fastmix/megamix
> > • 0xC00 ~ 0xC3F: PGC for MIPI PHY
> > • 0xC40 ~ 0xC7F: PGC for PCIE_PHY
> > • 0xC80 ~ 0xCBF: Reserved
> > • 0xCC0 ~ 0xCFF: Reserved
> > • 0xD00 ~ 0xD3F: PGC for USB HSIC PHY
> >
> > And in 5.4 Power Management Unit (PMU) chapter,
> > you will find the USB OTG phy power is directly supplied by
> > VDD_USB_OTG1_3P3_IN/VDD_USB_OTG2_3P3_IN.
> >
> > http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX7DRM.pdf
> >
> > I understand that there's also some USB OTG code exist in NXP internal
> > tree, but that's legacy for early doc implementation and may be deprecated.
> > so i assume it should be gone.
> >
> > Hopefully i will double confirm with our IC designer tomorrow.
> >
> 
> USB OTG domains are absent from that list, true, but they are
> mentioned all of the place further in that section in register map
> documentation, which makes it difficult to tell which part of the
> datasheet is not up to date.
> 
> I'm going to drop those power domains for now, since I don't have a
> use-case for them and it would also allow me to get rid of the chunk
> of code you thought was messy. However it would be nice to get an
> updated version of RM where all of that is straightened out.
> 

I checked with our IC designer and he confirmed the USB OTG is removed
and not supported in GPC. SW should not control it, instead, its power
domain is handled by hardware automatically.

Currently there's true some incorrectness in GPC chapter, i already
reported the issue to the designer, but still no timeline when i
can get a updated version.

But i think it's fine if you're going to only support PCIE/MIPI/USB HSIC
PHY power domain. I suppose those bits are correct in RM.

Regards
Dong Aisheng

> 
> >> Support for any other power domain controlled by GPC is not present, and
> >> can be added at some later point.
> >>
> >> Testing of this code was done against a PCIe driver.
> >>
> >> Cc: [e-mail]
> >> Cc: Lucas Stach <[e-mail]>
> >> Cc: Fabio Estevam <[e-mail]>
> >> Cc: Dong Aisheng <[e-mail]>
> >> Cc: [e-mail]
> >> Cc: [e-mail]
> >> Signed-off-by: Andrey Smirnov <[e-mail]>
> >> ---
> >>  drivers/soc/Kconfig      |   1 +
> >>  drivers/soc/imx/Kconfig  |  10 ++
> >>  drivers/soc/imx/Makefile |   1 +
> >>  drivers/soc/imx/gpcv2.c  | 365 +++++++++++++++++++++++++++++++++++++++++++++++
> >>  4 files changed, 377 insertions(+)
> >>  create mode 100644 drivers/soc/imx/Kconfig
> >>  create mode 100644 drivers/soc/imx/gpcv2.c
> >>
> >> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
> >> index f09023f..8943543 100644
> >> --- a/drivers/soc/Kconfig
> >> +++ b/drivers/soc/Kconfig
> >> @@ -2,6 +2,7 @@ menu "SOC (System On Chip) specific Drivers"
> >>
> >>  source "drivers/soc/bcm/Kconfig"
> >>  source "drivers/soc/fsl/Kconfig"
> >> +source "drivers/soc/imx/Kconfig"
> >>  source "drivers/soc/mediatek/Kconfig"
> >>  source "drivers/soc/qcom/Kconfig"
> >>  source "drivers/soc/rockchip/Kconfig"
> >> diff --git a/drivers/soc/imx/Kconfig b/drivers/soc/imx/Kconfig
> >> new file mode 100644
> >> index 0000000..bc7f0ee0
> >> --- /dev/null
> >> +++ b/drivers/soc/imx/Kconfig
> >> @@ -0,0 +1,10 @@
> >> +menu "i.MX SoC drivers"
> >> +
> >> +config IMX7_PM_DOMAINS
> >> +     bool "i.MX7 PM domains"
> >> +     select PM_GENERIC_DOMAINS
> >> +     depends on SOC_IMX7D || (COMPILE_TEST && OF)
> >> +     default y if SOC_IMX7D
> >> +
> >> +endmenu
> >> +
> >> diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
> >> index 35861f5..5b6e396 100644
> >> --- a/drivers/soc/imx/Makefile
> >> +++ b/drivers/soc/imx/Makefile
> >> @@ -1 +1,2 @@
> >>  obj-y += gpc.o
> >> +obj-$(CONFIG_IMX7_PM_DOMAINS) += gpcv2.o
> >> diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
> >> new file mode 100644
> >> index 0000000..a27c5f8
> >> --- /dev/null
> >> +++ b/drivers/soc/imx/gpcv2.c
> >> @@ -0,0 +1,365 @@
> >> +/*
> >> + * Copyright 2017 Impinj, Inc
> >> + * Author: Andrey Smirnov <[e-mail]>
> >> + *
> >> + * Based on the code of analogus driver:
> >> + *
> >> + * Copyright 2015-2017 Pengutronix, Lucas Stach <[e-mail]>
> >> + *
> >> + * The code contained herein is licensed under the GNU General Public
> >> + * License. You may obtain a copy of the GNU General Public License
> >> + * Version 2 or later at the following locations:
> >> + *
> >> + * http://www.opensource.org/licenses/gpl-license.html
> >> + * http://www.gnu.org/copyleft/gpl.html
> >> + */
> >> +
> >> +#include <linux/platform_device.h>
> >> +#include <linux/pm_domain.h>
> >> +#include <linux/regmap.h>
> >> +#include <linux/regulator/consumer.h>
> >> +#include <dt-bindings/power/imx7-power.h>
> >> +
> >> +#define GPC_PGC_CPU_MAPPING  0xec
> >> +#define USB_HSIC_PHY_A7_DOMAIN       BIT(6)
> >> +#define USB_OTG2_PHY_A7_DOMAIN       BIT(5)
> >> +#define USB_OTG1_PHY_A7_DOMAIN       BIT(4)
> >> +#define PCIE_PHY_A7_DOMAIN   BIT(3)
> >> +#define MIPI_PHY_A7_DOMAIN   BIT(2)
> >> +
> >> +#define GPC_PU_PGC_SW_PUP_REQ        0xf8
> >> +#define GPC_PU_PGC_SW_PDN_REQ        0x104
> >> +#define USB_HSIC_PHY_SW_Pxx_REQ      BIT(4)
> >> +#define USB_OTG2_PHY_SW_Pxx_REQ      BIT(3)
> >> +#define USB_OTG1_PHY_SW_Pxx_REQ      BIT(2)
> >> +#define PCIE_PHY_SW_Pxx_REQ  BIT(1)
> >> +#define MIPI_PHY_SW_Pxx_REQ  BIT(0)
> >> +
> >
> > After apply, what i see is:
> > #define GPC_PU_PGC_SW_PUP_REQ   0xf8
> > #define GPC_PU_PGC_SW_PDN_REQ   0x104
> > #define USB_HSIC_PHY_SW_Pxx_REQ BIT(4)
> > #define USB_OTG2_PHY_SW_Pxx_REQ BIT(3)
> > #define USB_OTG1_PHY_SW_Pxx_REQ BIT(2)
> > #define PCIE_PHY_SW_Pxx_REQ     BIT(1)
> > #define MIPI_PHY_SW_Pxx_REQ     BIT(0)
> >
> > Looks quite tight,
> > Can we have one more TAB for the definition?
> > Like:
> > #define GPC_PU_PGC_SW_PUP_REQ           0xf8
> >
> 
> Sure, will do.
> 
> >> +#define GPC_MAX_REGISTER     0x1000
> >> +
> >> +#define GPC_PGC_nCTRL_PCR    BIT(0)
> >> +
> >> +struct imx7_pgc_domain {
> >> +     struct generic_pm_domain genpd;
> >> +     struct regmap *regmap;
> >> +     struct regulator *regulator;
> >> +
> >> +     unsigned int pgc_nctrl;
> >> +
> >> +     const struct {
> >> +             u32 pxx;
> >> +             u32 map;
> >> +     } bits;
> >> +
> >> +     const int voltage;
> >> +     struct device *dev;
> >> +};
> >> +
> >> +static int imx7_gpc_pu_pgc_sw_pxx_req(struct generic_pm_domain *genpd,
> >> +                                   bool on)
> >> +{
> >> +     struct imx7_pgc_domain *domain = container_of(genpd,
> >> +                                                   struct imx7_pgc_domain,
> >> +                                                   genpd);
> >> +     unsigned int offset = on ?
> >> +             GPC_PU_PGC_SW_PUP_REQ : GPC_PU_PGC_SW_PDN_REQ;
> >> +     const bool enable_power_control = domain->pgc_nctrl && !on;
> >> +     const bool has_regulator = !IS_ERR(domain->regulator);
> >> +     unsigned long deadline;
> >> +     int ret = 0;
> >> +
> >> +     regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
> >> +                        domain->bits.map, domain->bits.map);
> >> +
> >> +     if (has_regulator && on) {
> >> +             ret = regulator_enable(domain->regulator);
> >> +             if (ret) {
> >> +                     dev_err(domain->dev, "failed to enable regulator\n");
> >> +                     goto unmap;
> >> +             }
> >> +     }
> >> +
> >> +     if (enable_power_control)
> >> +             regmap_update_bits(domain->regmap, domain->pgc_nctrl,
> >> +                                GPC_PGC_nCTRL_PCR, GPC_PGC_nCTRL_PCR);
> >> +
> >> +     regmap_update_bits(domain->regmap, offset,
> >> +                        domain->bits.pxx, domain->bits.pxx);
> >> +
> >> +     /*
> >> +      * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
> >> +      * for PUP_REQ/PDN_REQ bit to be cleared
> >> +      */
> >> +     deadline = jiffies + msecs_to_jiffies(1);
> >> +     while (true) {
> >> +             u32 pxx_req;
> >> +
> >> +             regmap_read(domain->regmap, offset, &pxx_req);
> >> +
> >> +             if (!(pxx_req & domain->bits.pxx))
> >> +                     break;
> >> +
> >> +             if (time_after(jiffies, deadline)) {
> >> +                     dev_err(domain->dev, "falied to command PGC\n");
> >> +                     ret = -ETIMEDOUT;
> >> +                     /*
> >> +                      * If we were in a process of enabling a
> >> +                      * domain and failed we might as well disable
> >> +                      * the regulator we just enabled. And if it
> >> +                      * was the opposite situation and we failed to
> >> +                      * power down -- keep the regulator on
> >> +                      */
> >> +                     on = !on;
> >> +                     break;
> >> +             }
> >> +
> >> +             cpu_relax();
> >> +     }
> >> +
> >> +     if (enable_power_control)
> >> +             regmap_update_bits(domain->regmap, domain->pgc_nctrl,
> >> +                                GPC_PGC_nCTRL_PCR, 0);
> >> +
> >> +     if (has_regulator && !on) {
> >> +             int err;
> >> +
> >> +             err = regulator_disable(domain->regulator);
> >> +             if (err)
> >> +                     dev_err(domain->dev,
> >> +                             "failed to disable regulator: %d\n", ret);
> >> +             /* Preserve earlier error code */
> >> +             ret = ret ?: err;
> >> +     }
> >> +unmap:
> >> +     regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
> >> +                        domain->bits.map, 0);
> >> +     return ret;
> >> +}
> >> +
> >> +static int imx7_gpc_pu_pgc_sw_pup_req(struct generic_pm_domain *genpd)
> >> +{
> >> +     return imx7_gpc_pu_pgc_sw_pxx_req(genpd, true);
> >> +}
> >> +
> >> +static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
> >> +{
> >> +     return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
> >> +}
> >> +
> >> +static struct imx7_pgc_domain imx7_pgc_domains[] = {
> >> +     [IMX7_POWER_DOMAIN_USB_HSIC_PHY] = {
> >> +             .genpd = {
> >> +                     .name      = "usb-hsic-phy",
> >> +             },
> >> +             .bits  = {
> >> +                     .pxx = USB_HSIC_PHY_SW_Pxx_REQ,
> >> +                     .map = USB_HSIC_PHY_A7_DOMAIN,
> >> +             },
> >> +             .voltage   = 1200000,
> >> +             .pgc_nctrl = 0x0d00,
> >> +     },
> >> +
> >> +     [IMX7_POWER_DOMAIN_USB_OTG2_PHY] = {
> >> +             .genpd = {
> >> +                     .name      = "usb-otg2-phy",
> >> +             },
> >> +             .bits  = {
> >> +                     .pxx = USB_OTG2_PHY_SW_Pxx_REQ,
> >> +                     .map = USB_OTG2_PHY_A7_DOMAIN,
> >> +             },
> >> +     },
> >> +
> >> +     [IMX7_POWER_DOMAIN_USB_OTG1_PHY] = {
> >> +             .genpd = {
> >> +                     .name      = "usb-otg1-phy",
> >> +             },
> >> +             .bits  = {
> >> +                     .pxx = USB_OTG1_PHY_SW_Pxx_REQ,
> >> +                     .map = USB_OTG1_PHY_A7_DOMAIN,
> >> +             },
> >> +     },
> >> +
> >> +     [IMX7_POWER_DOMAIN_PCIE_PHY] = {
> >> +             .genpd = {
> >> +                     .name      = "pcie-phy",
> >> +             },
> >> +             .bits  = {
> >> +                     .pxx = PCIE_PHY_SW_Pxx_REQ,
> >> +                     .map = PCIE_PHY_A7_DOMAIN,
> >> +             },
> >> +             .voltage   = 1000000,
> >> +             .pgc_nctrl = 0x0c40,
> >> +     },
> >> +
> >> +     [IMX7_POWER_DOMAIN_MIPI_PHY] = {
> >> +             .genpd = {
> >> +                     .name      = "mipi-phy",
> >> +             },
> >> +             .bits  = {
> >> +                     .pxx = MIPI_PHY_SW_Pxx_REQ,
> >> +                     .map = MIPI_PHY_A7_DOMAIN,
> >> +             },
> >> +             .voltage   = 1000000,
> >> +             .pgc_nctrl = 0x0c00,
> >> +     },
> >> +};
> >> +
> >> +static int imx7_pgc_domain_probe(struct platform_device *pdev)
> >> +{
> >> +     struct imx7_pgc_domain *domain = pdev->dev.platform_data;
> >> +     int ret;
> >> +
> >> +     domain->dev = &pdev->dev;
> >> +
> >> +     ret = pm_genpd_init(&domain->genpd, NULL, true);
> >> +     if (ret) {
> >> +             dev_err(domain->dev, "Failed to init power domain\n");
> >> +             return ret;
> >> +     }
> >> +
> >> +     domain->regulator = devm_regulator_get_optional(domain->dev, "power");
> >> +     if (IS_ERR(domain->regulator) &&
> >> +         PTR_ERR(domain->regulator) != -ENODEV) {
> >> +             dev_err(domain->dev, "Failed to get domain's regulator\n");
> >> +             return PTR_ERR(domain->regulator);
> >> +     }
> >> +
> >> +     if (!IS_ERR(domain->regulator)) {
> >> +             if (!domain->voltage) {
> >> +                     WARN(1, "No voltage configured for domain's regulator");
> >> +                     return -EINVAL;
> >> +             }
> >> +
> >> +             regulator_set_voltage(domain->regulator,
> >> +                                   domain->voltage, domain->voltage);
> >> +     }
> >> +
> >> +     ret = of_genpd_add_provider_simple(domain->dev->of_node,
> >> +                                        &domain->genpd);
> >> +     if (ret) {
> >> +             dev_err(domain->dev, "Failed to add genpd provider\n");
> >> +             pm_genpd_remove(&domain->genpd);
> >> +     }
> >> +
> >> +     return ret;
> >> +}
> >> +
> >> +static int imx7_pgc_domain_remove(struct platform_device *pdev)
> >> +{
> >> +     struct imx7_pgc_domain *domain = pdev->dev.platform_data;
> >> +
> >> +     of_genpd_del_provider(domain->dev->of_node);
> >> +     pm_genpd_remove(&domain->genpd);
> >> +
> >> +     return 0;
> >> +}
> >> +
> >> +static const struct platform_device_id imx7_pgc_domain_id[] = {
> >> +     { "imx7-pgc-domain", },
> >> +     { },
> >> +};
> >> +
> >> +static struct platform_driver imx7_pgc_domain_driver = {
> >> +     .driver = {
> >> +             .name = "imx7-pgc",
> >> +     },
> >> +     .probe    = imx7_pgc_domain_probe,
> >> +     .remove   = imx7_pgc_domain_remove,
> >> +     .id_table = imx7_pgc_domain_id,
> >> +};
> >> +builtin_platform_driver(imx7_pgc_domain_driver)
> >
> > Again, i have a fundamental question about this patch implementation
> > that why we choose above way to register the power domain?
> >
> > I'm sorry that i did not know too much history.
> > Would you guys please help share some information?
> >
> > Because AFAIK this way will register each domain as a power domain
> > provider which is a bit violate the real HW and current power domain
> > framework design. And it is a bit more complicated to use than before.
> >
> > IMHO i would rather prefer the old traditional and simpler way that one
> > provider (GPC) supplies multiple domains (PCIE/MIPI/HSIC PHY domain)
> > than this patch does.
> >
> > However, i might be wrong. Please help to clear.
> >
> >> +
> >> +static int imx_gpcv2_probe(struct platform_device *pdev)
> >> +{
> >> +     static const struct regmap_config regmap_config = {
> >> +             .cache_type     = REGCACHE_NONE,
> >
> > You could drop it as GPC does.
> >
> 
> Yep, will remove.
> 
> >> +             .reg_bits       = 32,
> >> +             .val_bits       = 32,
> >> +             .reg_stride     = 4,
> >> +             .max_register   = GPC_MAX_REGISTER,
> >
> > Do you need add some readable/writeable reg?
> >
> > There seems to be some reserved regs in your range.
> > I can easily got the below crash:
> >
> > root@imx6ul7d:/sys/kernel/debug/regmap/303a0000.gpc# cat registers
> > [   54.985395] Unhandled fault: external abort on non-linefetch (0x1008) at 0xf08511c0
> > [   54.993166] pgd = ed02c000
> > [   54.995894] [f08511c0] *pgd=af00c811, *pte=303a0653, *ppte=303a0453
> > [   55.002215] Internal error: : 1008 [#1] SMP ARM
> > [   55.006756] Modules linked in:
> > [   55.009830] CPU: 0 PID: 750 Comm: cat Not tainted 4.11.0-rc1-00057-g2d60158-dirty #1169
> > [   55.017842] Hardware name: Freescale i.MX7 Dual (Device Tree)
> > [   55.023598] task: ee20ee40 task.stack: ed0f8000
> > [   55.028146] PC is at regmap_mmio_read32le+0x14/0x24
> > [   55.033035] LR is at regmap_mmio_read+0x40/0x60
> > [   55.037577] pc : [<c054f160>]    lr : [<c054f348>]    psr: 20070093
> > [   55.037577] sp : ed0f9dc8  ip : ed0f9dd8  fp : ed0f9dd4
> > [   55.049064] r10: ed160000  r9 : ef341000  r8 : ed0f9f80
> > [   55.054299] r7 : ed0f9e5c  r6 : ed0f9e5c  r5 : 000001c0  r4 : ef3bb900
> > [   55.060836] r3 : f0851000  r2 : ed0f9e5c  r1 : f08511c0  r0 : ef3bb900
> > [   55.067374] Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
> > [   55.074606] Control: 10c5387d  Table: ad02c06a  DAC: 00000051
> > [   55.080361] Process cat (pid: 750, stack limit = 0xed0f8210)
> > ....
> 
> Good catch, thank you! I'll update the code to make sure this doesn't happen.
> 
> Thanks,
> Andrey Smirnov

Dong Aisheng March 30, 2017, 7:04 a.m. UTC | #6

On Thu, Mar 30, 2017 at 02:58:36PM +0800, Dong Aisheng wrote:
> On Mon, Mar 27, 2017 at 11:42:15AM -0700, Andrey Smirnov wrote:
> > On Thu, Mar 23, 2017 at 11:24 PM, Dong Aisheng <[e-mail]> wrote:
> > > On Tue, Mar 21, 2017 at 07:50:04AM -0700, Andrey Smirnov wrote:
> > >> Add code allowing for control of various power domains managed by GPCv2
> > >> IP block found in i.MX7 series of SoCs. Power domains covered by this
> > >> patch are:
> > >>
> > >>     - PCIE PHY
> > >>     - MIPI PHY
> > >>     - USB HSIC PHY
> > >>     - USB OTG1/2 PHY
> > >>
> > >
> > > You probably may need drop USB OTG which is not claimed in current RM.
> > > See the PGC definition in 5.5.10 GPC Memory Map section.
> > >
> > > Each PGC (CPU type, MIX type, PU type) will occupy 64 Bytes address space,
> > > the specific base address of each PGC are listed as below.
> > > • 0x800 ~ 0x83F : PGC for A7 core0
> > > • 0x840 ~ 0x87F: PGC for A7 core1
> > > • 0x880 ~ 0x8BF: PGC for A7 SCU
> > > • 0xA00 ~ 0xA3F: PGC for fastmix/megamix
> > > • 0xC00 ~ 0xC3F: PGC for MIPI PHY
> > > • 0xC40 ~ 0xC7F: PGC for PCIE_PHY
> > > • 0xC80 ~ 0xCBF: Reserved
> > > • 0xCC0 ~ 0xCFF: Reserved
> > > • 0xD00 ~ 0xD3F: PGC for USB HSIC PHY
> > >
> > > And in 5.4 Power Management Unit (PMU) chapter,
> > > you will find the USB OTG phy power is directly supplied by
> > > VDD_USB_OTG1_3P3_IN/VDD_USB_OTG2_3P3_IN.
> > >
> > > http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX7DRM.pdf
> > >
> > > I understand that there's also some USB OTG code exist in NXP internal
> > > tree, but that's legacy for early doc implementation and may be deprecated.
> > > so i assume it should be gone.
> > >
> > > Hopefully i will double confirm with our IC designer tomorrow.
> > >
> > 
> > USB OTG domains are absent from that list, true, but they are
> > mentioned all of the place further in that section in register map
> > documentation, which makes it difficult to tell which part of the
> > datasheet is not up to date.
> > 
> > I'm going to drop those power domains for now, since I don't have a
> > use-case for them and it would also allow me to get rid of the chunk
> > of code you thought was messy. However it would be nice to get an
> > updated version of RM where all of that is straightened out.
> > 
> 
> I checked with our IC designer and he confirmed the USB OTG is removed
> and not supported in GPC. SW should not control it, instead, its power
> domain is handled by hardware automatically.
> 
> Currently there's true some incorrectness in GPC chapter, i already
> reported the issue to the designer, but still no timeline when i
> can get a updated version.
> 
> But i think it's fine if you're going to only support PCIE/MIPI/USB HSIC
> PHY power domain. I suppose those bits are correct in RM.
> 

BTW, would you please CC my company email next time?
[e-mail]

Then i can see them in time to help the review.

Regards
Dong Aisheng

Dong Aisheng March 30, 2017, 7:51 a.m. UTC | #7

Hi Lucas,

On Thu, Mar 23, 2017 at 03:35:49PM +0100, Lucas Stach wrote:
> Hi Dong,
> 
> Am Freitag, den 24.03.2017, 14:24 +0800 schrieb Dong Aisheng:
> [...]
> > > +static struct platform_driver imx7_pgc_domain_driver = {
> > > +	.driver = {
> > > +		.name = "imx7-pgc",
> > > +	},
> > > +	.probe    = imx7_pgc_domain_probe,
> > > +	.remove   = imx7_pgc_domain_remove,
> > > +	.id_table = imx7_pgc_domain_id,
> > > +};
> > > +builtin_platform_driver(imx7_pgc_domain_driver)
> > 
> > Again, i have a fundamental question about this patch implementation
> > that why we choose above way to register the power domain?
> > 
> > I'm sorry that i did not know too much history.
> > Would you guys please help share some information?
> > 
> > Because AFAIK this way will register each domain as a power domain
> > provider which is a bit violate the real HW and current power domain
> > framework design. And it is a bit more complicated to use than before.
> > 
> > IMHO i would rather prefer the old traditional and simpler way that one
> > provider (GPC) supplies multiple domains (PCIE/MIPI/HSIC PHY domain)
> > than this patch does.
> > 
> > However, i might be wrong. Please help to clear.
> 
> This way we can properly describe each power domain with the regulator
> supplying the domain and the clocks of the devices inside the domain in
> the device tree.
> 

Thanks for the explaination. I understand that purpose.

Now my concern is why we doing things like this:
Builtin two platforms driver and use one to dynamically create
device to trigger another driver bind to register the domain.

static int imx7_pgc_domain_probe(struct platform_device *pdev)
{
        of_genpd_add_provider_simple(domain->dev->of_node,
                                           &domain->genpd);
}

static struct platform_driver imx7_pgc_domain_driver = {
        .driver = {
                .name = "imx7-pgc",
        },
        .probe    = imx7_pgc_domain_probe,
};
builtin_platform_driver(imx7_pgc_domain_driver)


static int imx_gpcv2_probe(struct platform_device *pdev)
{

        for_each_child_of_node(pgc_np, np) {
                pd_pdev = platform_device_alloc("imx7-pgc-domain",
                                                domain_index);
                ret = platform_device_add(pd_pdev);
	}
}

static struct platform_driver imx_gpc_driver = {
        .driver = {
                .name = "imx-gpcv2",
                .of_match_table = imx_gpcv2_dt_ids,
        }, 
        .probe = imx_gpcv2_probe,
};
builtin_platform_driver(imx_gpc_driver)

Is there any special purpose or i missed something?

Can we just use one or a simple core_initcall(imx_gpcv2_probe) cause
this probably should be registered early for other consumers?

Personally i'd be more like Rockchip's power domain implementation.
See:
arch/arm/boot/dts/rk3288.dtsi
drivers/soc/rockchip/pm_domains.c
Dcumentation/devicetree/bindings/soc/rockchip/power_domain.txt

How about refer to the Rockchip's way?

Then it could also address our issues and the binding would be
still like:
gpc: gpc@303a0000 {
        compatible = "fsl,imx7d-gpc";
        reg = <0x303a0000 0x1000>;
        interrupt-controller;
        interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
        #interrupt-cells = <3>;
        interrupt-parent = <&intc>;

        pgc {
                #address-cells = <1>;
                #size-cells = <0>;

                pgc_pcie_phy: power-domain@IMX7_POWER_DOMAIN_PCIE_PHY {
                        reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
                        power-supply = <&reg_1p0d>;
			clocks = <xxx>;
                };

		....
        };
};

It also drops #power-domain-cells and register domain by
one provider with multi domains which is more align with HW.

How do you think of it?

Regards
Dong Aisheng

> This is needed as for the upstream version we are controlling the
> regulator from the GPC driver, as opposed to the downstream version,
> where each device has to implement the regulator handling and power
> up/down sequencing.
> 
> See the rationale in the commits adding the multidomain support to the
> i.MX6 GPC.
> 
> Regards,
> Lucas
>

Lucas Stach March 31, 2017, 12:28 p.m. UTC | #8

Hi Dong,

Am Samstag, den 01.04.2017, 12:10 +0800 schrieb Dong Aisheng:
[...]
> > If we need the domains to be up before the consumers, the only
> > way to deal with that is to select CONFIG_PM and
> > CONFIG_PM_GENERIC_DOMAINS from the platform, so we have proper probe
> > defer handling for consumer devices of the power domains.
> > 
> 
> A bit confuse about these words...

If those options are selected we get proper PROBE_DEFER handling for
consumers of the power domain, so probe order doesn't matter.

> > > Personally i'd be more like Rockchip's power domain implementation.
> > 
> > Why?
> > 
> > > See:
> > > arch/arm/boot/dts/rk3288.dtsi
> > > drivers/soc/rockchip/pm_domains.c
> > > Dcumentation/devicetree/bindings/soc/rockchip/power_domain.txt
> > > 
> > > How about refer to the Rockchip's way?
> > 
> > Why? We just changed the way how it's done for GPCv1, after more than 1
> > year of those patches being on the list. Why should we do it differently
> > for GPCv2?
> > 
> 
> Hmm?
> 
> I just thought your GPCv1 change was picked a few weeks ago (Feb 17 2017)
> and there's no current users in kernel of the new binding.
> That's why i come out of the idea if we could improve it before any users.
> 
> Maybe i made mistake?

The patches to change this have been out for over 1 year. I'm less than
motivated to change the binding again, after it has gone through the DT
review and has finally been picked up.

> See:
> commit 721cabf6c6600dbe689ee2782bc087270e97e652
> Author: Lucas Stach <[e-mail]>
> Date:   Fri Feb 17 20:02:44 2017 +0100
> 
>     soc: imx: move PGC handling to a new GPC driver
>     
>     This is an almost complete re-write of the previous GPC power gating control
>     code found in the IMX architecture code. It supports both the old and the new
>     DT binding, allowing more domains to be added later and generally makes the
>     driver easier to extend, while keeping compatibility with existing DTBs.
>     
>     As the result, all functionality regarding the power gating controller
>     gets removed from the IMX architecture GPC driver.  It keeps only the
>     IRQ controller code in the architecture, as this is closely coupled to
>     the CPU idle implementation.
>     
>     Signed-off-by: Lucas Stach <[e-mail]>
>     Signed-off-by: Shawn Guo <[e-mail]>
> 
> > > 
> > > Then it could also address our issues and the binding would be
> > > still like:
> > > gpc: gpc@303a0000 {
> > >         compatible = "fsl,imx7d-gpc";
> > >         reg = <0x303a0000 0x1000>;
> > >         interrupt-controller;
> > >         interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
> > >         #interrupt-cells = <3>;
> > >         interrupt-parent = <&intc>;
> > > 
> > >         pgc {
> > >                 #address-cells = <1>;
> > >                 #size-cells = <0>;
> > > 
> > >                 pgc_pcie_phy: power-domain@IMX7_POWER_DOMAIN_PCIE_PHY {
> > >                         reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
> > >                         power-supply = <&reg_1p0d>;
> > > 			clocks = <xxx>;
> > >                 };
> > > 
> > > 		....
> > >         };
> > > };
> > > 
> > > It also drops #power-domain-cells and register domain by
> > > one provider with multi domains which is more align with HW.
> > > 
> > > How do you think of it?
> > 
> > How is this more aligned with the hardware? Both options are an
> > arbitrary abstraction chosen in the DT binding.
> > 
> 
> GPC is a Power Controller which controls multi power domains to subsystem
> by its different registers bits.
> e.g. PCIE/MIPI/USB HSIC PHY.
> • 0xC00 ~ 0xC3F: PGC for MIPI PHY
> • 0xC40 ~ 0xC7F: PGC for PCIE_PHY
> • 0xD00 ~ 0xD3F: PGC for USB HSIC PHY
> 
> So i thought it looks more like GPC is a power domain provider with multi
> domains support to different subsystems from HW point of view.
> 
> Isn't that true?

Linux and hardware devices are not required to match 1:1. There is
nothing that would make subdividing a single hardware device into
multiple ones bad style.

> 
> And there's also other two concerns:
> First, current genpd sysfs output still not include provider.
> e.g.
> root@imx6qdlsolo:~# cat /sys/kernel/debug/pm_genpd/pm_genpd_summary 
> domain                          status          slaves
>     /device                                             runtime status
> ----------------------------------------------------------------------
> PU                              off-0           
>     /devices/soc0/soc/130000.gpu                        suspended
>     /devices/soc0/soc/134000.gpu                        suspended
>     /devices/soc0/soc/2204000.gpu                       suspended
>     /devices/soc0/soc/2000000.aips-bus/2040000.vpu      suspended
> ARM                             off-0           
> 
> I wonder it might be a bit mess once the provider is added while each
> domain is registered as a virtual provider.

The provider is a Linux device. Linux devices don't necessarily have to
correspond to hardware devices. There is no such rule.

> 
> Second, it sacrifices a bit performance when look-up PM domain in
> genpd_get_from_provider if every domain is a provider.
> 
The performance penalty of a list walk won't hurt us in the probe path,
where we are (re-)probing entire devices. There is a lot more going on
than a simple list walk.

> Though it is arguable that currently only 3 domains support on MX7,
> but who knows the future when it becomes much more.
> 
> However, i did see many exist users in kernel using one provider one
> domain way. Maybe i'm over worried and it's not big deal.

I see that one provider with multiple domains is used more often, that
doesn't means it's necessarily better. At least I haven't hear a
convincing argument on why the chosen implementation in the GPC driver
is worse than the alternative.

Regards,
Lucas

Dong Aisheng April 1, 2017, 4:10 a.m. UTC | #9

Hi Lucas,

Thanks for the explaination.

On Wed, Mar 29, 2017 at 06:08:31PM +0200, Lucas Stach wrote:
> Hi Dong,
> 
> Am Donnerstag, den 30.03.2017, 15:51 +0800 schrieb Dong Aisheng:
> > Hi Lucas,
> > 
> > On Thu, Mar 23, 2017 at 03:35:49PM +0100, Lucas Stach wrote:
> > > Hi Dong,
> > > 
> > > Am Freitag, den 24.03.2017, 14:24 +0800 schrieb Dong Aisheng:
> > > [...]
> > > > > +static struct platform_driver imx7_pgc_domain_driver = {
> > > > > +	.driver = {
> > > > > +		.name = "imx7-pgc",
> > > > > +	},
> > > > > +	.probe    = imx7_pgc_domain_probe,
> > > > > +	.remove   = imx7_pgc_domain_remove,
> > > > > +	.id_table = imx7_pgc_domain_id,
> > > > > +};
> > > > > +builtin_platform_driver(imx7_pgc_domain_driver)
> > > > 
> > > > Again, i have a fundamental question about this patch implementation
> > > > that why we choose above way to register the power domain?
> > > > 
> > > > I'm sorry that i did not know too much history.
> > > > Would you guys please help share some information?
> > > > 
> > > > Because AFAIK this way will register each domain as a power domain
> > > > provider which is a bit violate the real HW and current power domain
> > > > framework design. And it is a bit more complicated to use than before.
> > > > 
> > > > IMHO i would rather prefer the old traditional and simpler way that one
> > > > provider (GPC) supplies multiple domains (PCIE/MIPI/HSIC PHY domain)
> > > > than this patch does.
> > > > 
> > > > However, i might be wrong. Please help to clear.
> > > 
> > > This way we can properly describe each power domain with the regulator
> > > supplying the domain and the clocks of the devices inside the domain in
> > > the device tree.
> > > 
> > 
> > Thanks for the explaination. I understand that purpose.
> > 
> > Now my concern is why we doing things like this:
> > Builtin two platforms driver and use one to dynamically create
> > device to trigger another driver bind to register the domain.
> > 
> > static int imx7_pgc_domain_probe(struct platform_device *pdev)
> > {
> >         of_genpd_add_provider_simple(domain->dev->of_node,
> >                                            &domain->genpd);
> > }
> > 
> > static struct platform_driver imx7_pgc_domain_driver = {
> >         .driver = {
> >                 .name = "imx7-pgc",
> >         },
> >         .probe    = imx7_pgc_domain_probe,
> > };
> > builtin_platform_driver(imx7_pgc_domain_driver)
> > 
> > 
> > static int imx_gpcv2_probe(struct platform_device *pdev)
> > {
> > 
> >         for_each_child_of_node(pgc_np, np) {
> >                 pd_pdev = platform_device_alloc("imx7-pgc-domain",
> >                                                 domain_index);
> >                 ret = platform_device_add(pd_pdev);
> > 	}
> > }
> > 
> > static struct platform_driver imx_gpc_driver = {
> >         .driver = {
> >                 .name = "imx-gpcv2",
> >                 .of_match_table = imx_gpcv2_dt_ids,
> >         }, 
> >         .probe = imx_gpcv2_probe,
> > };
> > builtin_platform_driver(imx_gpc_driver)
> > 
> > Is there any special purpose or i missed something?
> 
> Yes, clocks and regulators can be looked up by the devices attached to
> the DT nodes. This makes handling of those easy (or at all possible, the
> regulator API doesn't allow to get regulators without the proper devnode
> attached to a DT node).
> 

That probably is not true.
Regulator API does allow to get regulators without dev or devnode parameter.
e.g. reg_arm = regulator_get(NULL, "vddarm");

However, i did feel like that this using is not quite suitable for DT
users while it introduces limitation and dependencies in device tree.

Then, platform driver/device mode seems truely a better approach for this
issue.

> > Can we just use one or a simple core_initcall(imx_gpcv2_probe) cause
> > this probably should be registered early for other consumers?
> 
> Initcall levels are not going to work. We are dealing with regulators,
> which can have supplies that are only probed when other modules are
> loaded. 

I see. A clear explain.

> If we need the domains to be up before the consumers, the only
> way to deal with that is to select CONFIG_PM and
> CONFIG_PM_GENERIC_DOMAINS from the platform, so we have proper probe
> defer handling for consumer devices of the power domains.
> 

A bit confuse about these words...

> > Personally i'd be more like Rockchip's power domain implementation.
> 
> Why?
> 
> > See:
> > arch/arm/boot/dts/rk3288.dtsi
> > drivers/soc/rockchip/pm_domains.c
> > Dcumentation/devicetree/bindings/soc/rockchip/power_domain.txt
> > 
> > How about refer to the Rockchip's way?
> 
> Why? We just changed the way how it's done for GPCv1, after more than 1
> year of those patches being on the list. Why should we do it differently
> for GPCv2?
> 

Hmm?

I just thought your GPCv1 change was picked a few weeks ago (Feb 17 2017)
and there's no current users in kernel of the new binding.
That's why i come out of the idea if we could improve it before any users.

Maybe i made mistake?

See:
commit 721cabf6c6600dbe689ee2782bc087270e97e652
Author: Lucas Stach <[e-mail]>
Date:   Fri Feb 17 20:02:44 2017 +0100

    soc: imx: move PGC handling to a new GPC driver
    
    This is an almost complete re-write of the previous GPC power gating control
    code found in the IMX architecture code. It supports both the old and the new
    DT binding, allowing more domains to be added later and generally makes the
    driver easier to extend, while keeping compatibility with existing DTBs.
    
    As the result, all functionality regarding the power gating controller
    gets removed from the IMX architecture GPC driver.  It keeps only the
    IRQ controller code in the architecture, as this is closely coupled to
    the CPU idle implementation.
    
    Signed-off-by: Lucas Stach <[e-mail]>
    Signed-off-by: Shawn Guo <[e-mail]>

> > 
> > Then it could also address our issues and the binding would be
> > still like:
> > gpc: gpc@303a0000 {
> >         compatible = "fsl,imx7d-gpc";
> >         reg = <0x303a0000 0x1000>;
> >         interrupt-controller;
> >         interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
> >         #interrupt-cells = <3>;
> >         interrupt-parent = <&intc>;
> > 
> >         pgc {
> >                 #address-cells = <1>;
> >                 #size-cells = <0>;
> > 
> >                 pgc_pcie_phy: power-domain@IMX7_POWER_DOMAIN_PCIE_PHY {
> >                         reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
> >                         power-supply = <&reg_1p0d>;
> > 			clocks = <xxx>;
> >                 };
> > 
> > 		....
> >         };
> > };
> > 
> > It also drops #power-domain-cells and register domain by
> > one provider with multi domains which is more align with HW.
> > 
> > How do you think of it?
> 
> How is this more aligned with the hardware? Both options are an
> arbitrary abstraction chosen in the DT binding.
> 

GPC is a Power Controller which controls multi power domains to subsystem
by its different registers bits.
e.g. PCIE/MIPI/USB HSIC PHY.
• 0xC00 ~ 0xC3F: PGC for MIPI PHY
• 0xC40 ~ 0xC7F: PGC for PCIE_PHY
• 0xD00 ~ 0xD3F: PGC for USB HSIC PHY

So i thought it looks more like GPC is a power domain provider with multi
domains support to different subsystems from HW point of view.

Isn't that true?

And there's also other two concerns:
First, current genpd sysfs output still not include provider.
e.g.
root@imx6qdlsolo:~# cat /sys/kernel/debug/pm_genpd/pm_genpd_summary 
domain                          status          slaves
    /device                                             runtime status
----------------------------------------------------------------------
PU                              off-0           
    /devices/soc0/soc/130000.gpu                        suspended
    /devices/soc0/soc/134000.gpu                        suspended
    /devices/soc0/soc/2204000.gpu                       suspended
    /devices/soc0/soc/2000000.aips-bus/2040000.vpu      suspended
ARM                             off-0           

I wonder it might be a bit mess once the provider is added while each
domain is registered as a virtual provider.

Second, it sacrifices a bit performance when look-up PM domain in
genpd_get_from_provider if every domain is a provider.

Though it is arguable that currently only 3 domains support on MX7,
but who knows the future when it becomes much more.

However, i did see many exist users in kernel using one provider one
domain way. Maybe i'm over worried and it's not big deal.

Rafael,
Would you provide some guidance on this issue?

> Regards,
> Lucas
> 

Regards
Dong Aisheng

Dong Aisheng April 11, 2017, 3:22 a.m. UTC | #10

On Fri, Mar 31, 2017 at 02:28:11PM +0200, Lucas Stach wrote:
> Hi Dong,
> 
> Am Samstag, den 01.04.2017, 12:10 +0800 schrieb Dong Aisheng:
> [...]
> > > If we need the domains to be up before the consumers, the only
> > > way to deal with that is to select CONFIG_PM and
> > > CONFIG_PM_GENERIC_DOMAINS from the platform, so we have proper probe
> > > defer handling for consumer devices of the power domains.
> > > 
> > 
> > A bit confuse about these words...
> 
> If those options are selected we get proper PROBE_DEFER handling for
> consumers of the power domain, so probe order doesn't matter.
> 
> > > > Personally i'd be more like Rockchip's power domain implementation.
> > > 
> > > Why?
> > > 
> > > > See:
> > > > arch/arm/boot/dts/rk3288.dtsi
> > > > drivers/soc/rockchip/pm_domains.c
> > > > Dcumentation/devicetree/bindings/soc/rockchip/power_domain.txt
> > > > 
> > > > How about refer to the Rockchip's way?
> > > 
> > > Why? We just changed the way how it's done for GPCv1, after more than 1
> > > year of those patches being on the list. Why should we do it differently
> > > for GPCv2?
> > > 
> > 
> > Hmm?
> > 
> > I just thought your GPCv1 change was picked a few weeks ago (Feb 17 2017)
> > and there's no current users in kernel of the new binding.
> > That's why i come out of the idea if we could improve it before any users.
> > 
> > Maybe i made mistake?
> 
> The patches to change this have been out for over 1 year. I'm less than
> motivated to change the binding again, after it has gone through the DT
> review and has finally been picked up.
> 
> > See:
> > commit 721cabf6c6600dbe689ee2782bc087270e97e652
> > Author: Lucas Stach <[e-mail]>
> > Date:   Fri Feb 17 20:02:44 2017 +0100
> > 
> >     soc: imx: move PGC handling to a new GPC driver
> >     
> >     This is an almost complete re-write of the previous GPC power gating control
> >     code found in the IMX architecture code. It supports both the old and the new
> >     DT binding, allowing more domains to be added later and generally makes the
> >     driver easier to extend, while keeping compatibility with existing DTBs.
> >     
> >     As the result, all functionality regarding the power gating controller
> >     gets removed from the IMX architecture GPC driver.  It keeps only the
> >     IRQ controller code in the architecture, as this is closely coupled to
> >     the CPU idle implementation.
> >     
> >     Signed-off-by: Lucas Stach <[e-mail]>
> >     Signed-off-by: Shawn Guo <[e-mail]>
> > 
> > > > 
> > > > Then it could also address our issues and the binding would be
> > > > still like:
> > > > gpc: gpc@303a0000 {
> > > >         compatible = "fsl,imx7d-gpc";
> > > >         reg = <0x303a0000 0x1000>;
> > > >         interrupt-controller;
> > > >         interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
> > > >         #interrupt-cells = <3>;
> > > >         interrupt-parent = <&intc>;
> > > > 
> > > >         pgc {
> > > >                 #address-cells = <1>;
> > > >                 #size-cells = <0>;
> > > > 
> > > >                 pgc_pcie_phy: power-domain@IMX7_POWER_DOMAIN_PCIE_PHY {
> > > >                         reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
> > > >                         power-supply = <&reg_1p0d>;
> > > > 			clocks = <xxx>;
> > > >                 };
> > > > 
> > > > 		....
> > > >         };
> > > > };
> > > > 
> > > > It also drops #power-domain-cells and register domain by
> > > > one provider with multi domains which is more align with HW.
> > > > 
> > > > How do you think of it?
> > > 
> > > How is this more aligned with the hardware? Both options are an
> > > arbitrary abstraction chosen in the DT binding.
> > > 
> > 
> > GPC is a Power Controller which controls multi power domains to subsystem
> > by its different registers bits.
> > e.g. PCIE/MIPI/USB HSIC PHY.
> > • 0xC00 ~ 0xC3F: PGC for MIPI PHY
> > • 0xC40 ~ 0xC7F: PGC for PCIE_PHY
> > • 0xD00 ~ 0xD3F: PGC for USB HSIC PHY
> > 
> > So i thought it looks more like GPC is a power domain provider with multi
> > domains support to different subsystems from HW point of view.
> > 
> > Isn't that true?
> 
> Linux and hardware devices are not required to match 1:1. There is
> nothing that would make subdividing a single hardware device into
> multiple ones bad style.
> 
> > 
> > And there's also other two concerns:
> > First, current genpd sysfs output still not include provider.
> > e.g.
> > root@imx6qdlsolo:~# cat /sys/kernel/debug/pm_genpd/pm_genpd_summary 
> > domain                          status          slaves
> >     /device                                             runtime status
> > ----------------------------------------------------------------------
> > PU                              off-0           
> >     /devices/soc0/soc/130000.gpu                        suspended
> >     /devices/soc0/soc/134000.gpu                        suspended
> >     /devices/soc0/soc/2204000.gpu                       suspended
> >     /devices/soc0/soc/2000000.aips-bus/2040000.vpu      suspended
> > ARM                             off-0           
> > 
> > I wonder it might be a bit mess once the provider is added while each
> > domain is registered as a virtual provider.
> 
> The provider is a Linux device. Linux devices don't necessarily have to
> correspond to hardware devices. There is no such rule.
> 
> > 
> > Second, it sacrifices a bit performance when look-up PM domain in
> > genpd_get_from_provider if every domain is a provider.
> > 
> The performance penalty of a list walk won't hurt us in the probe path,
> where we are (re-)probing entire devices. There is a lot more going on
> than a simple list walk.
> 

It is mostly care in a simulation platform like Zebu while the code
execution time is quite long even it's very small in real word.

> > Though it is arguable that currently only 3 domains support on MX7,
> > but who knows the future when it becomes much more.
> > 
> > However, i did see many exist users in kernel using one provider one
> > domain way. Maybe i'm over worried and it's not big deal.
> 
> I see that one provider with multiple domains is used more often, that
> doesn't means it's necessarily better. At least I haven't hear a
> convincing argument on why the chosen implementation in the GPC driver
> is worse than the alternative.
> 

Well, this is not a strong objection. I could also accept it if no
objection from maintainer.

And seems Shawn already picked the patches. So never mind,
let's keep going on.

Regards
Dong Aisheg

> Regards,
> Lucas
>

Patch

diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index f09023f..8943543 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -2,6 +2,7 @@  menu "SOC (System On Chip) specific Drivers"
 
 source "drivers/soc/bcm/Kconfig"
 source "drivers/soc/fsl/Kconfig"
+source "drivers/soc/imx/Kconfig"
 source "drivers/soc/mediatek/Kconfig"
 source "drivers/soc/qcom/Kconfig"
 source "drivers/soc/rockchip/Kconfig"
diff --git a/drivers/soc/imx/Kconfig b/drivers/soc/imx/Kconfig
new file mode 100644
index 0000000..bc7f0ee0
--- /dev/null
+++ b/drivers/soc/imx/Kconfig
@@ -0,0 +1,10 @@ 
+menu "i.MX SoC drivers"
+
+config IMX7_PM_DOMAINS
+	bool "i.MX7 PM domains"
+	select PM_GENERIC_DOMAINS
+	depends on SOC_IMX7D || (COMPILE_TEST && OF)
+	default y if SOC_IMX7D
+
+endmenu
+
diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
index 35861f5..5b6e396 100644
--- a/drivers/soc/imx/Makefile
+++ b/drivers/soc/imx/Makefile
@@ -1 +1,2 @@ 
 obj-y += gpc.o
+obj-$(CONFIG_IMX7_PM_DOMAINS) += gpcv2.o
diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
new file mode 100644
index 0000000..a27c5f8
--- /dev/null
+++ b/drivers/soc/imx/gpcv2.c
@@ -0,0 +1,365 @@ 
+/*
+ * Copyright 2017 Impinj, Inc
+ * Author: Andrey Smirnov <[e-mail]>
+ *
+ * Based on the code of analogus driver:
+ *
+ * Copyright 2015-2017 Pengutronix, Lucas Stach <[e-mail]>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <dt-bindings/power/imx7-power.h>
+
+#define GPC_PGC_CPU_MAPPING	0xec
+#define USB_HSIC_PHY_A7_DOMAIN	BIT(6)
+#define USB_OTG2_PHY_A7_DOMAIN	BIT(5)
+#define USB_OTG1_PHY_A7_DOMAIN	BIT(4)
+#define PCIE_PHY_A7_DOMAIN	BIT(3)
+#define MIPI_PHY_A7_DOMAIN	BIT(2)
+
+#define GPC_PU_PGC_SW_PUP_REQ	0xf8
+#define GPC_PU_PGC_SW_PDN_REQ	0x104
+#define USB_HSIC_PHY_SW_Pxx_REQ	BIT(4)
+#define USB_OTG2_PHY_SW_Pxx_REQ	BIT(3)
+#define USB_OTG1_PHY_SW_Pxx_REQ	BIT(2)
+#define PCIE_PHY_SW_Pxx_REQ	BIT(1)
+#define MIPI_PHY_SW_Pxx_REQ	BIT(0)
+
+#define GPC_MAX_REGISTER	0x1000
+
+#define GPC_PGC_nCTRL_PCR	BIT(0)
+
+struct imx7_pgc_domain {
+	struct generic_pm_domain genpd;
+	struct regmap *regmap;
+	struct regulator *regulator;
+
+	unsigned int pgc_nctrl;
+
+	const struct {
+		u32 pxx;
+		u32 map;
+	} bits;
+
+	const int voltage;
+	struct device *dev;
+};
+
+static int imx7_gpc_pu_pgc_sw_pxx_req(struct generic_pm_domain *genpd,
+				      bool on)
+{
+	struct imx7_pgc_domain *domain = container_of(genpd,
+						      struct imx7_pgc_domain,
+						      genpd);
+	unsigned int offset = on ?
+		GPC_PU_PGC_SW_PUP_REQ : GPC_PU_PGC_SW_PDN_REQ;
+	const bool enable_power_control = domain->pgc_nctrl && !on;
+	const bool has_regulator = !IS_ERR(domain->regulator);
+	unsigned long deadline;
+	int ret = 0;
+
+	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+			   domain->bits.map, domain->bits.map);
+
+	if (has_regulator && on) {
+		ret = regulator_enable(domain->regulator);
+		if (ret) {
+			dev_err(domain->dev, "failed to enable regulator\n");
+			goto unmap;
+		}
+	}
+
+	if (enable_power_control)
+		regmap_update_bits(domain->regmap, domain->pgc_nctrl,
+				   GPC_PGC_nCTRL_PCR, GPC_PGC_nCTRL_PCR);
+
+	regmap_update_bits(domain->regmap, offset,
+			   domain->bits.pxx, domain->bits.pxx);
+
+	/*
+	 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
+	 * for PUP_REQ/PDN_REQ bit to be cleared
+	 */
+	deadline = jiffies + msecs_to_jiffies(1);
+	while (true) {
+		u32 pxx_req;
+
+		regmap_read(domain->regmap, offset, &pxx_req);
+
+		if (!(pxx_req & domain->bits.pxx))
+			break;
+
+		if (time_after(jiffies, deadline)) {
+			dev_err(domain->dev, "falied to command PGC\n");
+			ret = -ETIMEDOUT;
+			/*
+			 * If we were in a process of enabling a
+			 * domain and failed we might as well disable
+			 * the regulator we just enabled. And if it
+			 * was the opposite situation and we failed to
+			 * power down -- keep the regulator on
+			 */
+			on = !on;
+			break;
+		}
+
+		cpu_relax();
+	}
+
+	if (enable_power_control)
+		regmap_update_bits(domain->regmap, domain->pgc_nctrl,
+				   GPC_PGC_nCTRL_PCR, 0);
+
+	if (has_regulator && !on) {
+		int err;
+
+		err = regulator_disable(domain->regulator);
+		if (err)
+			dev_err(domain->dev,
+				"failed to disable regulator: %d\n", ret);
+		/* Preserve earlier error code */
+		ret = ret ?: err;
+	}
+unmap:
+	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+			   domain->bits.map, 0);
+	return ret;
+}
+
+static int imx7_gpc_pu_pgc_sw_pup_req(struct generic_pm_domain *genpd)
+{
+	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, true);
+}
+
+static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
+{
+	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
+}
+
+static struct imx7_pgc_domain imx7_pgc_domains[] = {
+	[IMX7_POWER_DOMAIN_USB_HSIC_PHY] = {
+		.genpd = {
+			.name      = "usb-hsic-phy",
+		},
+		.bits  = {
+			.pxx = USB_HSIC_PHY_SW_Pxx_REQ,
+			.map = USB_HSIC_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1200000,
+		.pgc_nctrl = 0x0d00,
+	},
+
+	[IMX7_POWER_DOMAIN_USB_OTG2_PHY] = {
+		.genpd = {
+			.name      = "usb-otg2-phy",
+		},
+		.bits  = {
+			.pxx = USB_OTG2_PHY_SW_Pxx_REQ,
+			.map = USB_OTG2_PHY_A7_DOMAIN,
+		},
+	},
+
+	[IMX7_POWER_DOMAIN_USB_OTG1_PHY] = {
+		.genpd = {
+			.name      = "usb-otg1-phy",
+		},
+		.bits  = {
+			.pxx = USB_OTG1_PHY_SW_Pxx_REQ,
+			.map = USB_OTG1_PHY_A7_DOMAIN,
+		},
+	},
+
+	[IMX7_POWER_DOMAIN_PCIE_PHY] = {
+		.genpd = {
+			.name      = "pcie-phy",
+		},
+		.bits  = {
+			.pxx = PCIE_PHY_SW_Pxx_REQ,
+			.map = PCIE_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc_nctrl = 0x0c40,
+	},
+
+	[IMX7_POWER_DOMAIN_MIPI_PHY] = {
+		.genpd = {
+			.name      = "mipi-phy",
+		},
+		.bits  = {
+			.pxx = MIPI_PHY_SW_Pxx_REQ,
+			.map = MIPI_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc_nctrl = 0x0c00,
+	},
+};
+
+static int imx7_pgc_domain_probe(struct platform_device *pdev)
+{
+	struct imx7_pgc_domain *domain = pdev->dev.platform_data;
+	int ret;
+
+	domain->dev = &pdev->dev;
+
+	ret = pm_genpd_init(&domain->genpd, NULL, true);
+	if (ret) {
+		dev_err(domain->dev, "Failed to init power domain\n");
+		return ret;
+	}
+
+	domain->regulator = devm_regulator_get_optional(domain->dev, "power");
+	if (IS_ERR(domain->regulator) &&
+	    PTR_ERR(domain->regulator) != -ENODEV) {
+		dev_err(domain->dev, "Failed to get domain's regulator\n");
+		return PTR_ERR(domain->regulator);
+	}
+
+	if (!IS_ERR(domain->regulator)) {
+		if (!domain->voltage) {
+			WARN(1, "No voltage configured for domain's regulator");
+			return -EINVAL;
+		}
+
+		regulator_set_voltage(domain->regulator,
+				      domain->voltage, domain->voltage);
+	}
+
+	ret = of_genpd_add_provider_simple(domain->dev->of_node,
+					   &domain->genpd);
+	if (ret) {
+		dev_err(domain->dev, "Failed to add genpd provider\n");
+		pm_genpd_remove(&domain->genpd);
+	}
+
+	return ret;
+}
+
+static int imx7_pgc_domain_remove(struct platform_device *pdev)
+{
+	struct imx7_pgc_domain *domain = pdev->dev.platform_data;
+
+	of_genpd_del_provider(domain->dev->of_node);
+	pm_genpd_remove(&domain->genpd);
+
+	return 0;
+}
+
+static const struct platform_device_id imx7_pgc_domain_id[] = {
+	{ "imx7-pgc-domain", },
+	{ },
+};
+
+static struct platform_driver imx7_pgc_domain_driver = {
+	.driver = {
+		.name = "imx7-pgc",
+	},
+	.probe    = imx7_pgc_domain_probe,
+	.remove   = imx7_pgc_domain_remove,
+	.id_table = imx7_pgc_domain_id,
+};
+builtin_platform_driver(imx7_pgc_domain_driver)
+
+static int imx_gpcv2_probe(struct platform_device *pdev)
+{
+	static const struct regmap_config regmap_config = {
+		.cache_type	= REGCACHE_NONE,
+		.reg_bits	= 32,
+		.val_bits	= 32,
+		.reg_stride	= 4,
+		.max_register	= GPC_MAX_REGISTER,
+	};
+	struct device *dev = &pdev->dev;
+	struct device_node *pgc_np, *np;
+	struct regmap *regmap;
+	struct resource *res;
+	void __iomem *base;
+	int ret;
+
+	pgc_np = of_get_child_by_name(dev->of_node, "pgc");
+	if (!pgc_np) {
+		dev_err(dev, "No power domains specified in DT\n");
+		return -EINVAL;
+	}
+
+	res  = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(dev, base, &regmap_config);
+	if (IS_ERR(regmap)) {
+		ret = PTR_ERR(regmap);
+		dev_err(dev, "failed to init regmap (%d)\n", ret);
+		return ret;
+	}
+
+	for_each_child_of_node(pgc_np, np) {
+		struct platform_device *pd_pdev;
+		struct imx7_pgc_domain *domain;
+		u32 domain_index;
+
+		ret = of_property_read_u32(np, "reg", &domain_index);
+		if (ret) {
+			dev_err(dev, "Failed to read 'reg' property\n");
+			of_node_put(np);
+			return ret;
+		}
+
+		if (domain_index >= ARRAY_SIZE(imx7_pgc_domains)) {
+			dev_warn(dev,
+				 "Domain index %d is out of bounds\n",
+				 domain_index);
+			continue;
+		}
+
+		domain = &imx7_pgc_domains[domain_index];
+		domain->regmap = regmap;
+		domain->genpd.power_on  = imx7_gpc_pu_pgc_sw_pup_req;
+		domain->genpd.power_off = imx7_gpc_pu_pgc_sw_pdn_req;
+
+		pd_pdev = platform_device_alloc("imx7-pgc-domain",
+						domain_index);
+		if (!pd_pdev) {
+			dev_err(dev, "Failed to allocate platform device\n");
+			of_node_put(np);
+			return -ENOMEM;
+		}
+
+		pd_pdev->dev.platform_data = domain;
+		pd_pdev->dev.parent = dev;
+		pd_pdev->dev.of_node = np;
+
+		ret = platform_device_add(pd_pdev);
+		if (ret) {
+			platform_device_put(pd_pdev);
+			of_node_put(np);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct of_device_id imx_gpcv2_dt_ids[] = {
+	{ .compatible = "fsl,imx7d-gpc" },
+	{ }
+};
+
+static struct platform_driver imx_gpc_driver = {
+	.driver = {
+		.name = "imx-gpcv2",
+		.of_match_table = imx_gpcv2_dt_ids,
+	},
+	.probe = imx_gpcv2_probe,
+};
+builtin_platform_driver(imx_gpc_driver)