Commit 6dc3e36f authored by Fabrice Gasnier's avatar Fabrice Gasnier Committed by Jonathan Cameron
Browse files

iio: counter: stm32-lptimer: Add power management support 



Add suspend/resume PM sleep ops. When going to low power, disable
active counter. Only active counter should be resumed: don't touch
disabled counter, as it may be used by other LPTimer MFD child driver.

Signed-off-by: default avatarFabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 74896202

drivers/iio/counter/stm32-lptimer-cnt.c

+55 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/iio/iio.h>

#include <linux/mfd/stm32-lptimer.h>

#include <linux/module.h>

#include <linux/pinctrl/consumer.h>

#include <linux/platform_device.h>



struct stm32_lptim_cnt {
@@ -23,6 +24,7 @@ struct stm32_lptim_cnt { 
	u32 preset;

	u32 polarity;

	u32 quadrature_mode;

	bool enabled;

};



static int stm32_lptim_is_enabled(struct stm32_lptim_cnt *priv)
@@ -50,6 +52,7 @@ static int stm32_lptim_set_enable_state(struct stm32_lptim_cnt *priv, 


	if (!enable) {

		clk_disable(priv->clk);

		priv->enabled = false;

		return 0;

	}
@@ -79,6 +82,7 @@ static int stm32_lptim_set_enable_state(struct stm32_lptim_cnt *priv, 
		regmap_write(priv->regmap, STM32_LPTIM_CR, 0);

		return ret;

	}

	priv->enabled = true;



	/* Start LP timer in continuous mode */

	return regmap_update_bits(priv->regmap, STM32_LPTIM_CR,
@@ -361,6 +365,56 @@ static int stm32_lptim_cnt_probe(struct platform_device *pdev) 
	return devm_iio_device_register(&pdev->dev, indio_dev);

}



#ifdef CONFIG_PM_SLEEP

static int stm32_lptim_cnt_suspend(struct device *dev)

{

	struct stm32_lptim_cnt *priv = dev_get_drvdata(dev);

	int ret;



	/* Only take care of enabled counter: don't disturb other MFD child */

	if (priv->enabled) {

		ret = stm32_lptim_setup(priv, 0);

		if (ret)

			return ret;



		ret = stm32_lptim_set_enable_state(priv, 0);

		if (ret)

			return ret;



		/* Force enable state for later resume */

		priv->enabled = true;

	}



	return pinctrl_pm_select_sleep_state(dev);

}



static int stm32_lptim_cnt_resume(struct device *dev)

{

	struct stm32_lptim_cnt *priv = dev_get_drvdata(dev);

	int ret;



	ret = pinctrl_pm_select_default_state(dev);

	if (ret)

		return ret;



	if (priv->enabled) {

		priv->enabled = false;

		ret = stm32_lptim_setup(priv, 1);

		if (ret)

			return ret;



		ret = stm32_lptim_set_enable_state(priv, 1);

		if (ret)

			return ret;

	}



	return 0;

}

#endif



static SIMPLE_DEV_PM_OPS(stm32_lptim_cnt_pm_ops, stm32_lptim_cnt_suspend,

			 stm32_lptim_cnt_resume);



static const struct of_device_id stm32_lptim_cnt_of_match[] = {

	{ .compatible = "st,stm32-lptimer-counter", },

	{},
@@ -372,6 +426,7 @@ static struct platform_driver stm32_lptim_cnt_driver = { 
	.driver = {

		.name = "stm32-lptimer-counter",

		.of_match_table = stm32_lptim_cnt_of_match,

		.pm = &stm32_lptim_cnt_pm_ops,

	},

};

module_platform_driver(stm32_lptim_cnt_driver);

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