linux-kernel - [PATCH] counter: stm32-timer-cnt: add power management support

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Message-ID: <1580899678-26393-1-git-send-email-fabrice.gasnier@st.com>
Date:   Wed, 5 Feb 2020 11:47:58 +0100
From:   Fabrice Gasnier <fabrice.gasnier@...com>
To:     <vilhelm.gray@...il.com>, <jic23@...nel.org>
CC:     <alexandre.torgue@...com>, <mcoquelin.stm32@...il.com>,
        <benjamin.gaignard@...com>, <fabrice.gasnier@...com>,
        <linux-iio@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] counter: stm32-timer-cnt: add power management support

Add suspend/resume PM sleep ops. When going to low power, enforce the
counter isn't active.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@...com>
---
 drivers/counter/stm32-timer-cnt.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
index 3eafcce..3b84503 100644
--- a/drivers/counter/stm32-timer-cnt.c
+++ b/drivers/counter/stm32-timer-cnt.c
@@ -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))
@@ -358,10 +359,33 @@ 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);
+	u32 cr1;
+
+	/* Check for active counter */
+	regmap_read(priv->regmap, TIM_CR1, &cr1);
+	if (cr1 & TIM_CR1_CEN)
+		return -EBUSY;
+
+	return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int __maybe_unused stm32_timer_cnt_resume(struct device *dev)
+{
+	return pinctrl_pm_select_default_state(dev);
+}
+
+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 +397,7 @@ 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);
-- 
2.7.4