diff mbox

[v8,15/18] cpufreq: Add cpufreq driver for Tegra124

Message ID 1425213881-5262-16-git-send-email-mikko.perttunen@kapsi.fi (mailing list archive)
State New, archived
Headers show

Commit Message

Mikko Perttunen March 1, 2015, 12:44 p.m. UTC 
From: Tuomas Tynkkynen <ttynkkynen@nvidia.com>

Add a new cpufreq driver for Tegra124. Instead of using the PLLX as
the CPU clocksource, switch immediately to the DFLL. It allows the use
of higher clock rates, and will automatically scale the CPU voltage as
well. Besides the CPU clocksource switch, we let the cpufreq-dt driver
for all the cpufreq operations.

This driver also relies on the DFLL driver to fill the OPP table for the
CPU0 device, so that the cpufreq-dt driver knows what frequencies to
use.

Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Mikko Perttunen <mikko.perttunen@kapsi.fi>
---
 drivers/cpufreq/Kconfig.arm        |   7 ++
 drivers/cpufreq/Makefile           |   1 +
 drivers/cpufreq/tegra124-cpufreq.c | 217 +++++++++++++++++++++++++++++++++++++
 3 files changed, 225 insertions(+)
 create mode 100644 drivers/cpufreq/tegra124-cpufreq.c

Comments

Paul Bolle March 2, 2015, 8:49 a.m. UTC | #1 
On Sun, 2015-03-01 at 14:44 +0200, Mikko Perttunen wrote:
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -256,6 +256,13 @@ config ARM_TEGRA20_CPUFREQ
>  	help
>  	  This adds the CPUFreq driver support for Tegra20 SOCs.
>  
> +config ARM_TEGRA124_CPUFREQ
> +	bool "Tegra124 CPUFreq support"

This adds a bool Kconfig symbol...

> +	depends on ARCH_TEGRA && CPUFREQ_DT
> +	default y
> +	help
> +	  This adds the CPUFreq driver support for Tegra124 SOCs.
> +
>  config ARM_PXA2xx_CPUFREQ
>  	tristate "Intel PXA2xx CPUfreq driver"
>  	depends on PXA27x || PXA25x
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 312d9c3..d478b83 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ)	+= sa1100-cpufreq.o
>  obj-$(CONFIG_ARM_SA1110_CPUFREQ)	+= sa1110-cpufreq.o
>  obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
>  obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)	+= tegra20-cpufreq.o
> +obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)	+= tegra124-cpufreq.o

... so this object will either not be built or be built-in.

>  obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ)	+= vexpress-spc-cpufreq.o
>  
>  ##################################################################################
> diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
> new file mode 100644
> index 0000000..45778ce
> --- /dev/null
> +++ b/drivers/cpufreq/tegra124-cpufreq.c
> @@ -0,0 +1,217 @@
> +/*
> + * Tegra 124 cpufreq driver
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
> +
> +#include <linux/clk.h>
> +#include <linux/cpufreq-dt.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>

Is linux/module.h needed?

> +#include <linux/of_device.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_opp.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/types.h>

[...]

> +static struct platform_driver tegra124_cpufreq_platdrv = {
> +	.driver = {
> +		.name	= "cpufreq-tegra124",
> +		.owner	= THIS_MODULE,

.owner will always be, in short, NULL.

> +	},
> +	.probe		= tegra124_cpufreq_probe,
> +	.remove		= tegra124_cpufreq_remove,
> +};

[...]

> +module_init(tegra_cpufreq_init);

This might as well be, I think, device_initcall().

> +MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
> +MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
> +MODULE_LICENSE("GPL v2");

The strings in these macros will always be preprocessed away, because
this driver cannot become a module.


Paul Bolle
Mikko Perttunen March 3, 2015, 11:33 a.m. UTC | #2 
On 03/02/2015 10:49 AM, Paul Bolle wrote:
> On Sun, 2015-03-01 at 14:44 +0200, Mikko Perttunen wrote:
>> --- a/drivers/cpufreq/Kconfig.arm
>> +++ b/drivers/cpufreq/Kconfig.arm
>> @@ -256,6 +256,13 @@ config ARM_TEGRA20_CPUFREQ
>>   	help
>>   	  This adds the CPUFreq driver support for Tegra20 SOCs.
>>
>> +config ARM_TEGRA124_CPUFREQ
>> +	bool "Tegra124 CPUFreq support"
>
> This adds a bool Kconfig symbol...
>
>> +	depends on ARCH_TEGRA && CPUFREQ_DT
>> +	default y
>> +	help
>> +	  This adds the CPUFreq driver support for Tegra124 SOCs.
>> +
>>   config ARM_PXA2xx_CPUFREQ
>>   	tristate "Intel PXA2xx CPUfreq driver"
>>   	depends on PXA27x || PXA25x
>> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
>> index 312d9c3..d478b83 100644
>> --- a/drivers/cpufreq/Makefile
>> +++ b/drivers/cpufreq/Makefile
>> @@ -77,6 +77,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ)	+= sa1100-cpufreq.o
>>   obj-$(CONFIG_ARM_SA1110_CPUFREQ)	+= sa1110-cpufreq.o
>>   obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
>>   obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)	+= tegra20-cpufreq.o
>> +obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)	+= tegra124-cpufreq.o
>
> ... so this object will either not be built or be built-in.
>
>>   obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ)	+= vexpress-spc-cpufreq.o
>>
>>   ##################################################################################
>> diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
>> new file mode 100644
>> index 0000000..45778ce
>> --- /dev/null
>> +++ b/drivers/cpufreq/tegra124-cpufreq.c
>> @@ -0,0 +1,217 @@
>> +/*
>> + * Tegra 124 cpufreq driver
>> + *
>> + * This software is licensed under the terms of the GNU General Public
>> + * License version 2, as published by the Free Software Foundation, and
>> + * may be copied, distributed, and modified under those terms.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/clk.h>
>> +#include <linux/cpufreq-dt.h>
>> +#include <linux/err.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>
> Is linux/module.h needed?
>
>> +#include <linux/of_device.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_opp.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/types.h>
>
> [...]
>
>> +static struct platform_driver tegra124_cpufreq_platdrv = {
>> +	.driver = {
>> +		.name	= "cpufreq-tegra124",
>> +		.owner	= THIS_MODULE,
>
> .owner will always be, in short, NULL.
>
>> +	},
>> +	.probe		= tegra124_cpufreq_probe,
>> +	.remove		= tegra124_cpufreq_remove,
>> +};
>
> [...]
>
>> +module_init(tegra_cpufreq_init);
>
> This might as well be, I think, device_initcall().
>
>> +MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
>> +MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
>> +MODULE_LICENSE("GPL v2");
>
> The strings in these macros will always be preprocessed away, because
> this driver cannot become a module.
>
>
> Paul Bolle
>

Well noticed! I changed the config symbol to be tristate.

Thanks,
Mikko Perttunen
Tuomas Tynkkynen March 4, 2015, 7:11 a.m. UTC | #3 
On 03/03/2015 01:33 PM, Mikko Perttunen wrote:
> On 03/02/2015 10:49 AM, Paul Bolle wrote:
>> On Sun, 2015-03-01 at 14:44 +0200, Mikko Perttunen wrote:
>>
>> [...]
>>
>>> +static struct platform_driver tegra124_cpufreq_platdrv = {
>>> +    .driver = {
>>> +        .name    = "cpufreq-tegra124",
>>> +        .owner    = THIS_MODULE,
>>
>> .owner will always be, in short, NULL.
>>

Which reminds me: recently there have been cleanups that remove the 
.owner field assignments (e.g. 30f51f248c1d "cpufreq: drop owner 
assignment from platform_drivers"), so it can be removed from here as well.


>
> Well noticed! I changed the config symbol to be tristate.
>
> Thanks,
> Mikko Perttunen
>
Mikko Perttunen March 5, 2015, 10:15 a.m. UTC | #4 
On 03/04/2015 09:11 AM, Tuomas Tynkkynen wrote:
> On 03/03/2015 01:33 PM, Mikko Perttunen wrote:
>> On 03/02/2015 10:49 AM, Paul Bolle wrote:
>>> On Sun, 2015-03-01 at 14:44 +0200, Mikko Perttunen wrote:
>>>
>>> [...]
>>>
>>>> +static struct platform_driver tegra124_cpufreq_platdrv = {
>>>> +    .driver = {
>>>> +        .name    = "cpufreq-tegra124",
>>>> +        .owner    = THIS_MODULE,
>>>
>>> .owner will always be, in short, NULL.
>>>
>
> Which reminds me: recently there have been cleanups that remove the
> .owner field assignments (e.g. 30f51f248c1d "cpufreq: drop owner
> assignment from platform_drivers"), so it can be removed from here as well.
>
>
>>
>> Well noticed! I changed the config symbol to be tristate.
>>
>> Thanks,
>> Mikko Perttunen
>>

Yep, will remove.

Mikko
diff mbox

Patch

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 08d88ba..86771e4 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -256,6 +256,13 @@  config ARM_TEGRA20_CPUFREQ
 	help
 	  This adds the CPUFreq driver support for Tegra20 SOCs.
 
+config ARM_TEGRA124_CPUFREQ
+	bool "Tegra124 CPUFreq support"
+	depends on ARCH_TEGRA && CPUFREQ_DT
+	default y
+	help
+	  This adds the CPUFreq driver support for Tegra124 SOCs.
+
 config ARM_PXA2xx_CPUFREQ
 	tristate "Intel PXA2xx CPUfreq driver"
 	depends on PXA27x || PXA25x
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 312d9c3..d478b83 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -77,6 +77,7 @@  obj-$(CONFIG_ARM_SA1100_CPUFREQ)	+= sa1100-cpufreq.o
 obj-$(CONFIG_ARM_SA1110_CPUFREQ)	+= sa1110-cpufreq.o
 obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)	+= tegra20-cpufreq.o
+obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)	+= tegra124-cpufreq.o
 obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ)	+= vexpress-spc-cpufreq.o
 
 ##################################################################################
diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
new file mode 100644
index 0000000..45778ce
--- /dev/null
+++ b/drivers/cpufreq/tegra124-cpufreq.c
@@ -0,0 +1,217 @@ 
+/*
+ * Tegra 124 cpufreq driver
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/cpufreq-dt.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/regulator/consumer.h>
+#include <linux/types.h>
+
+struct tegra124_cpufreq_priv {
+	struct regulator *vdd_cpu_reg;
+	struct clk *cpu_clk;
+	struct clk *pllp_clk;
+	struct clk *pllx_clk;
+	struct clk *dfll_clk;
+	struct platform_device *cpufreq_dt_pdev;
+};
+
+static int tegra124_cpu_switch_to_dfll(struct tegra124_cpufreq_priv *priv)
+{
+	struct clk *orig_parent;
+	int ret;
+
+	ret = clk_set_rate(priv->dfll_clk, clk_get_rate(priv->cpu_clk));
+	if (ret)
+		return ret;
+
+	orig_parent = clk_get_parent(priv->cpu_clk);
+	clk_set_parent(priv->cpu_clk, priv->pllp_clk);
+
+	ret = clk_prepare_enable(priv->dfll_clk);
+	if (ret)
+		goto out;
+
+	clk_set_parent(priv->cpu_clk, priv->dfll_clk);
+
+	return 0;
+
+out:
+	clk_set_parent(priv->cpu_clk, orig_parent);
+
+	return ret;
+}
+
+static void tegra124_cpu_switch_to_pllx(struct tegra124_cpufreq_priv *priv)
+{
+	clk_set_parent(priv->cpu_clk, priv->pllp_clk);
+	clk_disable_unprepare(priv->dfll_clk);
+	regulator_sync_voltage(priv->vdd_cpu_reg);
+	clk_set_parent(priv->cpu_clk, priv->pllx_clk);
+}
+
+static struct cpufreq_dt_platform_data cpufreq_dt_pd = {
+	.independent_clocks = false,
+};
+
+static int tegra124_cpufreq_probe(struct platform_device *pdev)
+{
+	struct tegra124_cpufreq_priv *priv;
+	struct device_node *np;
+	struct device *cpu_dev;
+	struct platform_device_info cpufreq_dt_devinfo = {};
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev)
+		return -ENODEV;
+
+	np = of_cpu_device_node_get(0);
+	if (!np)
+		return -ENODEV;
+
+	priv->vdd_cpu_reg = regulator_get(cpu_dev, "vdd-cpu");
+	if (IS_ERR(priv->vdd_cpu_reg)) {
+		ret = PTR_ERR(priv->vdd_cpu_reg);
+		goto out_put_np;
+	}
+
+	priv->cpu_clk = of_clk_get_by_name(np, "cpu_g");
+	if (IS_ERR(priv->cpu_clk)) {
+		ret = PTR_ERR(priv->cpu_clk);
+		goto out_put_vdd_cpu_reg;
+	}
+
+	priv->dfll_clk = of_clk_get_by_name(np, "dfll");
+	if (IS_ERR(priv->dfll_clk)) {
+		ret = PTR_ERR(priv->dfll_clk);
+		goto out_put_cpu_clk;
+	}
+
+	priv->pllx_clk = of_clk_get_by_name(np, "pll_x");
+	if (IS_ERR(priv->pllx_clk)) {
+		ret = PTR_ERR(priv->pllx_clk);
+		goto out_put_dfll_clk;
+	}
+
+	priv->pllp_clk = of_clk_get_by_name(np, "pll_p");
+	if (IS_ERR(priv->pllp_clk)) {
+		ret = PTR_ERR(priv->pllp_clk);
+		goto out_put_pllx_clk;
+	}
+
+	ret = tegra124_cpu_switch_to_dfll(priv);
+	if (ret)
+		goto out_put_pllp_clk;
+
+	cpufreq_dt_devinfo.name = "cpufreq-dt";
+	cpufreq_dt_devinfo.parent = &pdev->dev;
+	cpufreq_dt_devinfo.data = &cpufreq_dt_pd;
+	cpufreq_dt_devinfo.size_data = sizeof(cpufreq_dt_pd);
+
+	priv->cpufreq_dt_pdev =
+		platform_device_register_full(&cpufreq_dt_devinfo);
+	if (IS_ERR(priv->cpufreq_dt_pdev)) {
+		ret = PTR_ERR(priv->cpufreq_dt_pdev);
+		goto out_switch_to_pllx;
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+
+out_switch_to_pllx:
+	tegra124_cpu_switch_to_pllx(priv);
+out_put_pllp_clk:
+	clk_put(priv->pllp_clk);
+out_put_pllx_clk:
+	clk_put(priv->pllx_clk);
+out_put_dfll_clk:
+	clk_put(priv->dfll_clk);
+out_put_cpu_clk:
+	clk_put(priv->cpu_clk);
+out_put_vdd_cpu_reg:
+	regulator_put(priv->vdd_cpu_reg);
+out_put_np:
+	of_node_put(np);
+
+	return ret;
+}
+
+static int tegra124_cpufreq_remove(struct platform_device *pdev)
+{
+	struct tegra124_cpufreq_priv *priv = platform_get_drvdata(pdev);
+
+	platform_device_unregister(priv->cpufreq_dt_pdev);
+	tegra124_cpu_switch_to_pllx(priv);
+
+	clk_put(priv->pllp_clk);
+	clk_put(priv->pllx_clk);
+	clk_put(priv->dfll_clk);
+	clk_put(priv->cpu_clk);
+	regulator_put(priv->vdd_cpu_reg);
+
+	return 0;
+}
+
+static struct platform_driver tegra124_cpufreq_platdrv = {
+	.driver = {
+		.name	= "cpufreq-tegra124",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= tegra124_cpufreq_probe,
+	.remove		= tegra124_cpufreq_remove,
+};
+
+static int __init tegra_cpufreq_init(void)
+{
+	int ret;
+	struct platform_device *pdev;
+
+	if (!of_machine_is_compatible("nvidia,tegra124"))
+		return -ENODEV;
+
+	/*
+	 * Platform driver+device required for handling EPROBE_DEFER with
+	 * the regulator and the DFLL clock
+	 */
+	ret = platform_driver_register(&tegra124_cpufreq_platdrv);
+	if (ret)
+		return ret;
+
+	pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		platform_driver_unregister(&tegra124_cpufreq_platdrv);
+		return PTR_ERR(pdev);
+	}
+
+	return 0;
+}
+module_init(tegra_cpufreq_init);
+
+MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
+MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
+MODULE_LICENSE("GPL v2");