counter: stm32-timer-cnt: add power management support (c5b84255) · Commits · 戴 / test

drivers/counter/stm32-timer-cnt.c

+63 −0

Original line number	Diff line number	Diff line
		@@ -12,6 +12,7 @@
		#include <linux/iio/types.h>
		#include <linux/mfd/stm32-timers.h>
		#include <linux/module.h>
		#include <linux/pinctrl/consumer.h>
		#include <linux/platform_device.h>

		#define TIM_CCMR_CCXS (BIT(8) \| BIT(0))
		@@ -20,11 +21,20 @@
		#define TIM_CCER_MASK (TIM_CCER_CC1P \| TIM_CCER_CC1NP \| \
		TIM_CCER_CC2P \| TIM_CCER_CC2NP)

		struct stm32_timer_regs {
		u32 cr1;
		u32 cnt;
		u32 smcr;
		u32 arr;
		};

		struct stm32_timer_cnt {
		struct counter_device counter;
		struct regmap *regmap;
		struct clk *clk;
		u32 ceiling;
		bool enabled;
		struct stm32_timer_regs bak;
		};

		/**
		@@ -224,6 +234,9 @@ static ssize_t stm32_count_enable_write(struct counter_device *counter,
		clk_disable(priv->clk);
		}

		/* Keep enabled state to properly handle low power states */
		priv->enabled = enable;

		return len;
		}

		@@ -358,10 +371,59 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev)
		priv->counter.num_signals = ARRAY_SIZE(stm32_signals);
		priv->counter.priv = priv;

		platform_set_drvdata(pdev, priv);

		/* Register Counter device */
		return devm_counter_register(dev, &priv->counter);
		}

		static int __maybe_unused stm32_timer_cnt_suspend(struct device *dev)
		{
		struct stm32_timer_cnt *priv = dev_get_drvdata(dev);

		/* Only take care of enabled counter: don't disturb other MFD child */
		if (priv->enabled) {
		/* Backup registers that may get lost in low power mode */
		regmap_read(priv->regmap, TIM_SMCR, &priv->bak.smcr);
		regmap_read(priv->regmap, TIM_ARR, &priv->bak.arr);
		regmap_read(priv->regmap, TIM_CNT, &priv->bak.cnt);
		regmap_read(priv->regmap, TIM_CR1, &priv->bak.cr1);

		/* Disable the counter */
		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
		clk_disable(priv->clk);
		}

		return pinctrl_pm_select_sleep_state(dev);
		}

		static int __maybe_unused stm32_timer_cnt_resume(struct device *dev)
		{
		struct stm32_timer_cnt *priv = dev_get_drvdata(dev);
		int ret;

		ret = pinctrl_pm_select_default_state(dev);
		if (ret)
		return ret;

		if (priv->enabled) {
		clk_enable(priv->clk);

		/* Restore registers that may have been lost */
		regmap_write(priv->regmap, TIM_SMCR, priv->bak.smcr);
		regmap_write(priv->regmap, TIM_ARR, priv->bak.arr);
		regmap_write(priv->regmap, TIM_CNT, priv->bak.cnt);

		/* Also re-enables the counter */
		regmap_write(priv->regmap, TIM_CR1, priv->bak.cr1);
		}

		return 0;
		}

		static SIMPLE_DEV_PM_OPS(stm32_timer_cnt_pm_ops, stm32_timer_cnt_suspend,
		stm32_timer_cnt_resume);

		static const struct of_device_id stm32_timer_cnt_of_match[] = {
		{ .compatible = "st,stm32-timer-counter", },
		{},
		@@ -373,6 +435,7 @@ static struct platform_driver stm32_timer_cnt_driver = {
		.driver = {
		.name = "stm32-timer-counter",
		.of_match_table = stm32_timer_cnt_of_match,
		.pm = &stm32_timer_cnt_pm_ops,
		},
		};
		module_platform_driver(stm32_timer_cnt_driver);

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