[v2,15/17] power: reset: mt6323: add a driver for MT6323 power controller

Commit Message

Sean Wang April 25, 2018, 9:32 a.m. UTC

From: Sean Wang <[e-mail]>

The power device is responsible for externally down or up the power
of the remote MediaTek SoC through the tiny circuit BBPU inside PMIC RTC.

Though it's a part of RTC device, it would be better to be a standalone
driver than to be a part of existent RTC driver so as to let us make
concentration on works about power-controlling topic and to obtain
improvements while the subsystem power/reset constantly growing.

Currently, the most basic functionality supported is to just power off
the system by writing to a special bit field in BBPU register after the
system has reached pm_poweroff.

Signed-off-by: Sean Wang <[e-mail]>
---
 drivers/power/reset/Kconfig           | 10 ++++
 drivers/power/reset/Makefile          |  1 +
 drivers/power/reset/mt6323-poweroff.c | 97 +++++++++++++++++++++++++++++++++++
 include/linux/mfd/mt6397/rtc.h        |  1 +
 4 files changed, 109 insertions(+)
 create mode 100644 drivers/power/reset/mt6323-poweroff.c

Comments

Sebastian Reichel May 1, 2018, 12:56 p.m. UTC | #1

Hi,

On Wed, Apr 25, 2018 at 05:32:41PM +0800, [e-mail] wrote:
> From: Sean Wang <[e-mail]>
> 
> The power device is responsible for externally down or up the power
> of the remote MediaTek SoC through the tiny circuit BBPU inside PMIC RTC.
> 
> Though it's a part of RTC device, it would be better to be a standalone
> driver than to be a part of existent RTC driver so as to let us make
> concentration on works about power-controlling topic and to obtain
> improvements while the subsystem power/reset constantly growing.

I don't understand the above sentence. (I'm fine with adding the
driver)

> Currently, the most basic functionality supported is to just power off
> the system by writing to a special bit field in BBPU register after the
> system has reached pm_poweroff.
> 
> Signed-off-by: Sean Wang <[e-mail]>
> ---
>  drivers/power/reset/Kconfig           | 10 ++++
>  drivers/power/reset/Makefile          |  1 +
>  drivers/power/reset/mt6323-poweroff.c | 97 +++++++++++++++++++++++++++++++++++
>  include/linux/mfd/mt6397/rtc.h        |  1 +
>  4 files changed, 109 insertions(+)
>  create mode 100644 drivers/power/reset/mt6323-poweroff.c
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index df58fc8..7b49d71 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -128,6 +128,16 @@ config POWER_RESET_LTC2952
>  	  This driver supports an external powerdown trigger and board power
>  	  down via the LTC2952. Bindings are made in the device tree.
>  
> +config POWER_RESET_MT6323
> +	bool "MediaTek MT6323 power-off driver"
> +	depends on MFD_MT6397
> +	help
> +	  The power-off driver is responsible for externally shutdown down
> +	  the power of a remote MediaTek SoC MT6323 is connected to through
> +	  controlling a tiny circuit BBPU inside MT6323 RTC.
> +
> +	  Say Y if you have a board where MT6323 could be found.
> +
>  config POWER_RESET_QNAP
>  	bool "QNAP power-off driver"
>  	depends on OF_GPIO && PLAT_ORION
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index 7778c74..8836172 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
>  obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
>  obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
>  obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
> +obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o
>  obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
>  obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
>  obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
> diff --git a/drivers/power/reset/mt6323-poweroff.c b/drivers/power/reset/mt6323-poweroff.c
> new file mode 100644
> index 0000000..c195766
> --- /dev/null
> +++ b/drivers/power/reset/mt6323-poweroff.c
> @@ -0,0 +1,97 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Power off through MediaTek PMIC
> + *
> + * Copyright (C) 2018 MediaTek Inc.
> + *
> + * Author: Sean Wang <[e-mail]>
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/of.h>

Not needed

> +#include <linux/platform_device.h>
> +#include <linux/mfd/mt6397/core.h>
> +#include <linux/mfd/mt6397/rtc.h>
> +
> +struct mt6323_pwrc {
> +	struct device *dev;
> +	struct regmap *regmap;
> +	u32 base;
> +};
> +
> +static struct mt6323_pwrc *mt_pwrc;
> +
> +static void mt6323_do_pwroff(void)
> +{
> +	struct mt6323_pwrc *pwrc = mt_pwrc;
> +	unsigned int val;
> +	int ret;
> +
> +	regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY);
> +	regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR, 1);
> +
> +	ret = regmap_read_poll_timeout(pwrc->regmap,
> +				       pwrc->base + RTC_BBPU, val,
> +				       !(val & RTC_BBPU_CBUSY),
> +				       MTK_RTC_POLL_DELAY_US,
> +				       MTK_RTC_POLL_TIMEOUT);
> +	if (ret)
> +		dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret);
> +
> +	/* Wait some time until system down, otherwise, notice with a warn */
> +	mdelay(1000);
> +
> +	WARN_ONCE(1, "Unable to power off system\n");
> +}
> +
> +static int mt6323_pwrc_probe(struct platform_device *pdev)
> +{
> +	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
> +	struct mt6323_pwrc *pwrc;
> +	struct resource *res;
> +
> +	pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
> +	if (!pwrc)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	pwrc->base = res->start;
> +	pwrc->regmap = mt6397_chip->regmap;
> +	pwrc->dev = &pdev->dev;
> +	mt_pwrc = pwrc;
> +
> +	pm_power_off = &mt6323_do_pwroff;
> +
> +	return 0;
> +}
> +
> +static int mt6323_pwrc_remove(struct platform_device *pdev)
> +{
> +	if (pm_power_off == &mt6323_do_pwroff)
> +		pm_power_off = NULL;
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mt6323_pwrc_dt_match[] = {
> +	{ .compatible = "mediatek,mt6323-pwrc" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);

Don't forget to remove the DT table when you respin the series for
the requested binding changes.

> +static struct platform_driver mt6323_pwrc_driver = {
> +	.probe		= mt6323_pwrc_probe,
> +	.remove		= mt6323_pwrc_remove,
> +	.driver		= {
> +		.name	= "mt6323-pwrc",
> +		.of_match_table = mt6323_pwrc_dt_match,
> +	},
> +};
> +
> +module_platform_driver(mt6323_pwrc_driver);
> +
> +MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
> +MODULE_AUTHOR("Sean Wang <[e-mail]>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/mt6397/rtc.h b/include/linux/mfd/mt6397/rtc.h
> index 480977c..ac932c9 100644
> --- a/include/linux/mfd/mt6397/rtc.h
> +++ b/include/linux/mfd/mt6397/rtc.h
> @@ -16,6 +16,7 @@
>  
>  #define RTC_BBPU		0x0000
>  #define RTC_BBPU_CBUSY		BIT(6)
> +#define RTC_BBPU_KEY            (0x43 << 8)
>  
>  #define RTC_WRTGR		0x003c

The driver looks fine otherwise.

-- Sebastian

Sean Wang May 2, 2018, 2:31 a.m. UTC | #2

On Tue, 2018-05-01 at 14:56 +0200, Sebastian Reichel wrote:
> Hi,
> 
> On Wed, Apr 25, 2018 at 05:32:41PM +0800, [e-mail] wrote:
> > From: Sean Wang <[e-mail]>
> > 
> > The power device is responsible for externally down or up the power
> > of the remote MediaTek SoC through the tiny circuit BBPU inside PMIC RTC.
> > 
> > Though it's a part of RTC device, it would be better to be a standalone
> > driver than to be a part of existent RTC driver so as to let us make
> > concentration on works about power-controlling topic and to obtain
> > improvements while the subsystem power/reset constantly growing.
> 
> I don't understand the above sentence. (I'm fine with adding the
> driver)

Which I was actually meaning is that taking the poweroff driver as the
standalone one and placing it under driver/reset/power seems can simply
get a help from its subsystem either for function extension or bugfix in
the future. I thought that way is better than just an embedded one
somewhere in rtc driver or other drivers.

> > Currently, the most basic functionality supported is to just power off
> > the system by writing to a special bit field in BBPU register after the
> > system has reached pm_poweroff.
> > 
> > Signed-off-by: Sean Wang <[e-mail]>
> > ---
> >  drivers/power/reset/Kconfig           | 10 ++++
> >  drivers/power/reset/Makefile          |  1 +
> >  drivers/power/reset/mt6323-poweroff.c | 97 +++++++++++++++++++++++++++++++++++
> >  include/linux/mfd/mt6397/rtc.h        |  1 +
> >  4 files changed, 109 insertions(+)
> >  create mode 100644 drivers/power/reset/mt6323-poweroff.c
> > 
> > diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> > index df58fc8..7b49d71 100644
> > --- a/drivers/power/reset/Kconfig
> > +++ b/drivers/power/reset/Kconfig
> > @@ -128,6 +128,16 @@ config POWER_RESET_LTC2952
> >  	  This driver supports an external powerdown trigger and board power
> >  	  down via the LTC2952. Bindings are made in the device tree.
> >  
> > +config POWER_RESET_MT6323
> > +	bool "MediaTek MT6323 power-off driver"
> > +	depends on MFD_MT6397
> > +	help
> > +	  The power-off driver is responsible for externally shutdown down
> > +	  the power of a remote MediaTek SoC MT6323 is connected to through
> > +	  controlling a tiny circuit BBPU inside MT6323 RTC.
> > +
> > +	  Say Y if you have a board where MT6323 could be found.
> > +
> >  config POWER_RESET_QNAP
> >  	bool "QNAP power-off driver"
> >  	depends on OF_GPIO && PLAT_ORION
> > diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> > index 7778c74..8836172 100644
> > --- a/drivers/power/reset/Makefile
> > +++ b/drivers/power/reset/Makefile
> > @@ -11,6 +11,7 @@ obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
> >  obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
> >  obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
> >  obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
> > +obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o
> >  obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
> >  obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
> >  obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
> > diff --git a/drivers/power/reset/mt6323-poweroff.c b/drivers/power/reset/mt6323-poweroff.c
> > new file mode 100644
> > index 0000000..c195766
> > --- /dev/null
> > +++ b/drivers/power/reset/mt6323-poweroff.c
> > @@ -0,0 +1,97 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Power off through MediaTek PMIC
> > + *
> > + * Copyright (C) 2018 MediaTek Inc.
> > + *
> > + * Author: Sean Wang <[e-mail]>
> > + *
> > + */
> > +
> > +#include <linux/err.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> 
> Not needed

Will be removed.

> 
> > +#include <linux/platform_device.h>
> > +#include <linux/mfd/mt6397/core.h>
> > +#include <linux/mfd/mt6397/rtc.h>
> > +
> > +struct mt6323_pwrc {
> > +	struct device *dev;
> > +	struct regmap *regmap;
> > +	u32 base;
> > +};
> > +
> > +static struct mt6323_pwrc *mt_pwrc;
> > +
> > +static void mt6323_do_pwroff(void)
> > +{
> > +	struct mt6323_pwrc *pwrc = mt_pwrc;
> > +	unsigned int val;
> > +	int ret;
> > +
> > +	regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY);
> > +	regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR, 1);
> > +
> > +	ret = regmap_read_poll_timeout(pwrc->regmap,
> > +				       pwrc->base + RTC_BBPU, val,
> > +				       !(val & RTC_BBPU_CBUSY),
> > +				       MTK_RTC_POLL_DELAY_US,
> > +				       MTK_RTC_POLL_TIMEOUT);
> > +	if (ret)
> > +		dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret);
> > +
> > +	/* Wait some time until system down, otherwise, notice with a warn */
> > +	mdelay(1000);
> > +
> > +	WARN_ONCE(1, "Unable to power off system\n");
> > +}
> > +
> > +static int mt6323_pwrc_probe(struct platform_device *pdev)
> > +{
> > +	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
> > +	struct mt6323_pwrc *pwrc;
> > +	struct resource *res;
> > +
> > +	pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
> > +	if (!pwrc)
> > +		return -ENOMEM;
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	pwrc->base = res->start;
> > +	pwrc->regmap = mt6397_chip->regmap;
> > +	pwrc->dev = &pdev->dev;
> > +	mt_pwrc = pwrc;
> > +
> > +	pm_power_off = &mt6323_do_pwroff;
> > +
> > +	return 0;
> > +}
> > +
> > +static int mt6323_pwrc_remove(struct platform_device *pdev)
> > +{
> > +	if (pm_power_off == &mt6323_do_pwroff)
> > +		pm_power_off = NULL;
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id mt6323_pwrc_dt_match[] = {
> > +	{ .compatible = "mediatek,mt6323-pwrc" },
> > +	{},
> > +};
> > +MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
> 
> Don't forget to remove the DT table when you respin the series for
> the requested binding changes.
> 

Thanks. This table will be removed in the next version.


> > +static struct platform_driver mt6323_pwrc_driver = {
> > +	.probe		= mt6323_pwrc_probe,
> > +	.remove		= mt6323_pwrc_remove,
> > +	.driver		= {
> > +		.name	= "mt6323-pwrc",
> > +		.of_match_table = mt6323_pwrc_dt_match,
> > +	},
> > +};
> > +
> > +module_platform_driver(mt6323_pwrc_driver);
> > +
> > +MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
> > +MODULE_AUTHOR("Sean Wang <[e-mail]>");
> > +MODULE_LICENSE("GPL v2");
> > diff --git a/include/linux/mfd/mt6397/rtc.h b/include/linux/mfd/mt6397/rtc.h
> > index 480977c..ac932c9 100644
> > --- a/include/linux/mfd/mt6397/rtc.h
> > +++ b/include/linux/mfd/mt6397/rtc.h
> > @@ -16,6 +16,7 @@
> >  
> >  #define RTC_BBPU		0x0000
> >  #define RTC_BBPU_CBUSY		BIT(6)
> > +#define RTC_BBPU_KEY            (0x43 << 8)
> >  
> >  #define RTC_WRTGR		0x003c
> 
> The driver looks fine otherwise.
> 

Thanks.

> -- Sebastian
> _______________________________________________
> Linux-mediatek mailing list
> [e-mail]
> http://lists.infradead.org/mailman/listinfo/linux-mediatek

Patch

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index df58fc8..7b49d71 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -128,6 +128,16 @@  config POWER_RESET_LTC2952
 	  This driver supports an external powerdown trigger and board power
 	  down via the LTC2952. Bindings are made in the device tree.
 
+config POWER_RESET_MT6323
+	bool "MediaTek MT6323 power-off driver"
+	depends on MFD_MT6397
+	help
+	  The power-off driver is responsible for externally shutdown down
+	  the power of a remote MediaTek SoC MT6323 is connected to through
+	  controlling a tiny circuit BBPU inside MT6323 RTC.
+
+	  Say Y if you have a board where MT6323 could be found.
+
 config POWER_RESET_QNAP
 	bool "QNAP power-off driver"
 	depends on OF_GPIO && PLAT_ORION
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 7778c74..8836172 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -11,6 +11,7 @@  obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
 obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
 obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
 obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
+obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o
 obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
 obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
 obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
diff --git a/drivers/power/reset/mt6323-poweroff.c b/drivers/power/reset/mt6323-poweroff.c
new file mode 100644
index 0000000..c195766
--- /dev/null
+++ b/drivers/power/reset/mt6323-poweroff.c
@@ -0,0 +1,97 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Power off through MediaTek PMIC
+ *
+ * Copyright (C) 2018 MediaTek Inc.
+ *
+ * Author: Sean Wang <[e-mail]>
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/mt6397/core.h>
+#include <linux/mfd/mt6397/rtc.h>
+
+struct mt6323_pwrc {
+	struct device *dev;
+	struct regmap *regmap;
+	u32 base;
+};
+
+static struct mt6323_pwrc *mt_pwrc;
+
+static void mt6323_do_pwroff(void)
+{
+	struct mt6323_pwrc *pwrc = mt_pwrc;
+	unsigned int val;
+	int ret;
+
+	regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY);
+	regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR, 1);
+
+	ret = regmap_read_poll_timeout(pwrc->regmap,
+				       pwrc->base + RTC_BBPU, val,
+				       !(val & RTC_BBPU_CBUSY),
+				       MTK_RTC_POLL_DELAY_US,
+				       MTK_RTC_POLL_TIMEOUT);
+	if (ret)
+		dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret);
+
+	/* Wait some time until system down, otherwise, notice with a warn */
+	mdelay(1000);
+
+	WARN_ONCE(1, "Unable to power off system\n");
+}
+
+static int mt6323_pwrc_probe(struct platform_device *pdev)
+{
+	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
+	struct mt6323_pwrc *pwrc;
+	struct resource *res;
+
+	pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
+	if (!pwrc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pwrc->base = res->start;
+	pwrc->regmap = mt6397_chip->regmap;
+	pwrc->dev = &pdev->dev;
+	mt_pwrc = pwrc;
+
+	pm_power_off = &mt6323_do_pwroff;
+
+	return 0;
+}
+
+static int mt6323_pwrc_remove(struct platform_device *pdev)
+{
+	if (pm_power_off == &mt6323_do_pwroff)
+		pm_power_off = NULL;
+
+	return 0;
+}
+
+static const struct of_device_id mt6323_pwrc_dt_match[] = {
+	{ .compatible = "mediatek,mt6323-pwrc" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
+
+static struct platform_driver mt6323_pwrc_driver = {
+	.probe		= mt6323_pwrc_probe,
+	.remove		= mt6323_pwrc_remove,
+	.driver		= {
+		.name	= "mt6323-pwrc",
+		.of_match_table = mt6323_pwrc_dt_match,
+	},
+};
+
+module_platform_driver(mt6323_pwrc_driver);
+
+MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
+MODULE_AUTHOR("Sean Wang <[e-mail]>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/mt6397/rtc.h b/include/linux/mfd/mt6397/rtc.h
index 480977c..ac932c9 100644
--- a/include/linux/mfd/mt6397/rtc.h
+++ b/include/linux/mfd/mt6397/rtc.h
@@ -16,6 +16,7 @@ 
 
 #define RTC_BBPU		0x0000
 #define RTC_BBPU_CBUSY		BIT(6)
+#define RTC_BBPU_KEY            (0x43 << 8)
 
 #define RTC_WRTGR		0x003c