1 files changed, 139 insertions, 22 deletions

diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
index 2f82e8c32186..7d8962d6566a 100644
--- a/drivers/iio/trigger/stm32-timer-trigger.c
+++ b/drivers/iio/trigger/stm32-timer-trigger.c
@@ -75,14 +75,27 @@ static const void *stm32h7_valids_table[][MAX_VALIDS] = {
 	{ }, /* timer 17 */
 };
 
+struct stm32_timer_trigger_regs {
+	u32 cr1;
+	u32 cr2;
+	u32 psc;
+	u32 arr;
+	u32 cnt;
+	u32 smcr;
+};
+
 struct stm32_timer_trigger {
 	struct device *dev;
 	struct regmap *regmap;
 	struct clk *clk;
+	bool enabled;
 	u32 max_arr;
 	const void *triggers;
 	const void *valids;
 	bool has_trgo2;
+	struct mutex lock; /* concurrent sysfs configuration */
+	struct list_head tr_list;
+	struct stm32_timer_trigger_regs bak;
 };
 
 struct stm32_timer_trigger_cfg {
@@ -106,7 +119,7 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
 {
 	unsigned long long prd, div;
 	int prescaler = 0;
-	u32 ccer, cr1;
+	u32 ccer;
 
 	/* Period and prescaler values depends of clock rate */
 	div = (unsigned long long)clk_get_rate(priv->clk);
@@ -136,9 +149,11 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
 	if (ccer & TIM_CCER_CCXE)
 		return -EBUSY;
 
-	regmap_read(priv->regmap, TIM_CR1, &cr1);
-	if (!(cr1 & TIM_CR1_CEN))
+	mutex_lock(&priv->lock);
+	if (!priv->enabled) {
+		priv->enabled = true;
 		clk_enable(priv->clk);
+	}
 
 	regmap_write(priv->regmap, TIM_PSC, prescaler);
 	regmap_write(priv->regmap, TIM_ARR, prd - 1);
@@ -157,6 +172,7 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
 
 	/* Enable controller */
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
+	mutex_unlock(&priv->lock);
 
 	return 0;
 }
@@ -164,16 +180,13 @@ static int stm32_timer_start(struct stm32_timer_trigger *priv,
 static void stm32_timer_stop(struct stm32_timer_trigger *priv,
 			     struct iio_trigger *trig)
 {
-	u32 ccer, cr1;
+	u32 ccer;
 
 	regmap_read(priv->regmap, TIM_CCER, &ccer);
 	if (ccer & TIM_CCER_CCXE)
 		return;
 
-	regmap_read(priv->regmap, TIM_CR1, &cr1);
-	if (cr1 & TIM_CR1_CEN)
-		clk_disable(priv->clk);
-
+	mutex_lock(&priv->lock);
 	/* Stop timer */
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
@@ -188,6 +201,12 @@ static void stm32_timer_stop(struct stm32_timer_trigger *priv,
 
 	/* Make sure that registers are updated */
 	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
+
+	if (priv->enabled) {
+		priv->enabled = false;
+		clk_disable(priv->clk);
+	}
+	mutex_unlock(&priv->lock);
 }
 
 static ssize_t stm32_tt_store_frequency(struct device *dev,
@@ -302,8 +321,15 @@ static ssize_t stm32_tt_store_master_mode(struct device *dev,
 	for (i = 0; i <= master_mode_max; i++) {
 		if (!strncmp(master_mode_table[i], buf,
 			     strlen(master_mode_table[i]))) {
+			mutex_lock(&priv->lock);
+			if (!priv->enabled) {
+				/* Clock should be enabled first */
+				priv->enabled = true;
+				clk_enable(priv->clk);
+			}
 			regmap_update_bits(priv->regmap, TIM_CR2, mask,
 					   i << shift);
+			mutex_unlock(&priv->lock);
 			return len;
 		}
 	}
@@ -361,11 +387,21 @@ static const struct attribute_group *stm32_trigger_attr_groups[] = {
 static const struct iio_trigger_ops timer_trigger_ops = {
 };
 
-static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
+static void stm32_unregister_iio_triggers(struct stm32_timer_trigger *priv)
+{
+	struct iio_trigger *tr;
+
+	list_for_each_entry(tr, &priv->tr_list, alloc_list)
+		iio_trigger_unregister(tr);
+}
+
+static int stm32_register_iio_triggers(struct stm32_timer_trigger *priv)
 {
 	int ret;
 	const char * const *cur = priv->triggers;
 
+	INIT_LIST_HEAD(&priv->tr_list);
+
 	while (cur && *cur) {
 		struct iio_trigger *trig;
 		bool cur_is_trgo = stm32_timer_is_trgo_name(*cur);
@@ -392,9 +428,13 @@ static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
 
 		iio_trigger_set_drvdata(trig, priv);
 
-		ret = devm_iio_trigger_register(priv->dev, trig);
-		if (ret)
+		ret = iio_trigger_register(trig);
+		if (ret) {
+			stm32_unregister_iio_triggers(priv);
 			return ret;
+		}
+
+		list_add_tail(&trig->alloc_list, &priv->tr_list);
 		cur++;
 	}
 
@@ -441,7 +481,6 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
 				   int val, int val2, long mask)
 {
 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
-	u32 dat;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
@@ -452,19 +491,23 @@ static int stm32_counter_write_raw(struct iio_dev *indio_dev,
 		return -EINVAL;
 
 	case IIO_CHAN_INFO_ENABLE:
+		mutex_lock(&priv->lock);
 		if (val) {
-			regmap_read(priv->regmap, TIM_CR1, &dat);
-			if (!(dat & TIM_CR1_CEN))
+			if (!priv->enabled) {
+				priv->enabled = true;
 				clk_enable(priv->clk);
+			}
 			regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
 					   TIM_CR1_CEN);
 		} else {
-			regmap_read(priv->regmap, TIM_CR1, &dat);
 			regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
 					   0);
-			if (dat & TIM_CR1_CEN)
+			if (priv->enabled) {
+				priv->enabled = false;
 				clk_disable(priv->clk);
+			}
 		}
+		mutex_unlock(&priv->lock);
 		return 0;
 	}
 
@@ -560,7 +603,6 @@ static int stm32_set_enable_mode(struct iio_dev *indio_dev,
 {
 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
 	int sms = stm32_enable_mode2sms(mode);
-	u32 val;
 
 	if (sms < 0)
 		return sms;
@@ -568,11 +610,12 @@ static int stm32_set_enable_mode(struct iio_dev *indio_dev,
 	 * Triggered mode sets CEN bit automatically by hardware. So, first
 	 * enable counter clock, so it can use it. Keeps it in sync with CEN.
 	 */
-	if (sms == 6) {
-		regmap_read(priv->regmap, TIM_CR1, &val);
-		if (!(val & TIM_CR1_CEN))
-			clk_enable(priv->clk);
+	mutex_lock(&priv->lock);
+	if (sms == 6 && !priv->enabled) {
+		clk_enable(priv->clk);
+		priv->enabled = true;
 	}
+	mutex_unlock(&priv->lock);
 
 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
 
@@ -756,8 +799,9 @@ static int stm32_timer_trigger_probe(struct platform_device *pdev)
 	priv->triggers = triggers_table[index];
 	priv->valids = cfg->valids_table[index];
 	stm32_timer_detect_trgo2(priv);
+	mutex_init(&priv->lock);
 
-	ret = stm32_setup_iio_triggers(priv);
+	ret = stm32_register_iio_triggers(priv);
 	if (ret)
 		return ret;
 
@@ -766,6 +810,77 @@ static int stm32_timer_trigger_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static int stm32_timer_trigger_remove(struct platform_device *pdev)
+{
+	struct stm32_timer_trigger *priv = platform_get_drvdata(pdev);
+	u32 val;
+
+	/* Unregister triggers before everything can be safely turned off */
+	stm32_unregister_iio_triggers(priv);
+
+	/* Check if nobody else use the timer, then disable it */
+	regmap_read(priv->regmap, TIM_CCER, &val);
+	if (!(val & TIM_CCER_CCXE))
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+
+	if (priv->enabled)
+		clk_disable(priv->clk);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_timer_trigger_suspend(struct device *dev)
+{
+	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
+
+	/* Only take care of enabled timer: don't disturb other MFD child */
+	if (priv->enabled) {
+		/* Backup registers that may get lost in low power mode */
+		regmap_read(priv->regmap, TIM_CR1, &priv->bak.cr1);
+		regmap_read(priv->regmap, TIM_CR2, &priv->bak.cr2);
+		regmap_read(priv->regmap, TIM_PSC, &priv->bak.psc);
+		regmap_read(priv->regmap, TIM_ARR, &priv->bak.arr);
+		regmap_read(priv->regmap, TIM_CNT, &priv->bak.cnt);
+		regmap_read(priv->regmap, TIM_SMCR, &priv->bak.smcr);
+
+		/* Disable the timer */
+		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+		clk_disable(priv->clk);
+	}
+
+	return 0;
+}
+
+static int __maybe_unused stm32_timer_trigger_resume(struct device *dev)
+{
+	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
+	int ret;
+
+	if (priv->enabled) {
+		ret = clk_enable(priv->clk);
+		if (ret)
+			return ret;
+
+		/* restore master/slave modes */
+		regmap_write(priv->regmap, TIM_SMCR, priv->bak.smcr);
+		regmap_write(priv->regmap, TIM_CR2, priv->bak.cr2);
+
+		/* restore sampling_frequency (trgo / trgo2 triggers) */
+		regmap_write(priv->regmap, TIM_PSC, priv->bak.psc);
+		regmap_write(priv->regmap, TIM_ARR, priv->bak.arr);
+		regmap_write(priv->regmap, TIM_CNT, priv->bak.cnt);
+
+		/* Also re-enables the timer */
+		regmap_write(priv->regmap, TIM_CR1, priv->bak.cr1);
+	}
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(stm32_timer_trigger_pm_ops,
+			 stm32_timer_trigger_suspend,
+			 stm32_timer_trigger_resume);
+
 static const struct stm32_timer_trigger_cfg stm32_timer_trg_cfg = {
 	.valids_table = valids_table,
 	.num_valids_table = ARRAY_SIZE(valids_table),
@@ -790,9 +905,11 @@ MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
 
 static struct platform_driver stm32_timer_trigger_driver = {
 	.probe = stm32_timer_trigger_probe,
+	.remove = stm32_timer_trigger_remove,
 	.driver = {
 		.name = "stm32-timer-trigger",
 		.of_match_table = stm32_trig_of_match,
+		.pm = &stm32_timer_trigger_pm_ops,
 	},
 };
 module_platform_driver(stm32_timer_trigger_driver);