Re: [PATCH 2/2] rtc: stm32: add STM32H7 RTC support

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On 06/26/2017 11:51 AM, Amelie Delaunay wrote:
This patch adds support for STM32H7 RTC. On STM32H7, the RTC bus interface
clock (APB clock) needs to be enabled.

Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
---

A gentle ping about this patch.

Thanks,
Amelie
  drivers/rtc/rtc-stm32.c | 85 +++++++++++++++++++++++++++++++++++++++----------
  1 file changed, 68 insertions(+), 17 deletions(-)

diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
index bd57eb1..22f988b 100644
--- a/drivers/rtc/rtc-stm32.c
+++ b/drivers/rtc/rtc-stm32.c
@@ -94,11 +94,17 @@
  /* STM32_PWR_CR bit field */
  #define PWR_CR_DBP			BIT(8)
+struct stm32_rtc_data {
+	bool has_pclk;
+};
+
  struct stm32_rtc {
  	struct rtc_device *rtc_dev;
  	void __iomem *base;
  	struct regmap *dbp;
-	struct clk *ck_rtc;
+	struct stm32_rtc_data *data;
+	struct clk *pclk;
+	struct clk *rtc_ck;
  	int irq_alarm;
  };
@@ -122,9 +128,9 @@ static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
  		writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
/*
-		 * It takes around 2 ck_rtc clock cycles to enter in
+		 * It takes around 2 rtc_ck clock cycles to enter in
  		 * initialization phase mode (and have INITF flag set). As
-		 * slowest ck_rtc frequency may be 32kHz and highest should be
+		 * slowest rtc_ck frequency may be 32kHz and highest should be
  		 * 1MHz, we poll every 10 us with a timeout of 100ms.
  		 */
  		return readl_relaxed_poll_timeout_atomic(
@@ -153,7 +159,7 @@ static int stm32_rtc_wait_sync(struct stm32_rtc *rtc)
/*
  	 * Wait for RSF to be set to ensure the calendar registers are
-	 * synchronised, it takes around 2 ck_rtc clock cycles
+	 * synchronised, it takes around 2 rtc_ck clock cycles
  	 */
  	return readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
  						 isr,
@@ -456,7 +462,7 @@ static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
/*
  	 * Poll Alarm write flag to be sure that Alarm update is allowed: it
-	 * takes around 2 ck_rtc clock cycles
+	 * takes around 2 rtc_ck clock cycles
  	 */
  	ret = readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
  						isr,
@@ -490,8 +496,17 @@ static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  	.alarm_irq_enable = stm32_rtc_alarm_irq_enable,
  };
+static const struct stm32_rtc_data stm32_rtc_data = {
+	.has_pclk = false,
+};
+
+static const struct stm32_rtc_data stm32h7_rtc_data = {
+	.has_pclk = true,
+};
+
  static const struct of_device_id stm32_rtc_of_match[] = {
-	{ .compatible = "st,stm32-rtc" },
+	{ .compatible = "st,stm32-rtc", .data = &stm32_rtc_data },
+	{ .compatible = "st,stm32h7-rtc", .data = &stm32h7_rtc_data },
  	{}
  };
  MODULE_DEVICE_TABLE(of, stm32_rtc_of_match);
@@ -503,7 +518,7 @@ static int stm32_rtc_init(struct platform_device *pdev,
  	unsigned int rate;
  	int ret = 0;
- rate = clk_get_rate(rtc->ck_rtc);
+	rate = clk_get_rate(rtc->rtc_ck);
/* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */
  	pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT;
@@ -524,7 +539,7 @@ static int stm32_rtc_init(struct platform_device *pdev,
  		pred_a = pred_a_max;
  		pred_s = (rate / (pred_a + 1)) - 1;
- dev_warn(&pdev->dev, "ck_rtc is %s\n",
+		dev_warn(&pdev->dev, "rtc_ck is %s\n",
  			 (rate < ((pred_a + 1) * (pred_s + 1))) ?
  			 "fast" : "slow");
  	}
@@ -561,6 +576,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)
  {
  	struct stm32_rtc *rtc;
  	struct resource *res;
+	const struct of_device_id *match;
  	int ret;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
@@ -579,15 +595,37 @@ static int stm32_rtc_probe(struct platform_device *pdev)
  		return PTR_ERR(rtc->dbp);
  	}
- rtc->ck_rtc = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(rtc->ck_rtc)) {
-		dev_err(&pdev->dev, "no ck_rtc clock");
-		return PTR_ERR(rtc->ck_rtc);
+	match = of_match_device(stm32_rtc_of_match, &pdev->dev);
+	if (match && match->data)
+		rtc->data = (struct stm32_rtc_data *)match->data;
+	else
+		return -EINVAL;
+
+	if (!rtc->data->has_pclk) {
+		rtc->pclk = NULL;
+		rtc->rtc_ck = devm_clk_get(&pdev->dev, NULL);
+	} else {
+		rtc->pclk = devm_clk_get(&pdev->dev, "pclk");
+		if (rtc->data->has_pclk && IS_ERR(rtc->pclk)) {
+			dev_err(&pdev->dev, "no pclk clock");
+			return PTR_ERR(rtc->rtc_ck);
+		}
+		rtc->rtc_ck = devm_clk_get(&pdev->dev, "rtc_ck");
+	}
+	if (IS_ERR(rtc->rtc_ck)) {
+		dev_err(&pdev->dev, "no rtc_ck clock");
+		return PTR_ERR(rtc->rtc_ck);
  	}
- ret = clk_prepare_enable(rtc->ck_rtc);
+	if (rtc->data->has_pclk) {
+		ret = clk_prepare_enable(rtc->pclk);
+		if (ret)
+			return ret;
+	}
+
+	ret = clk_prepare_enable(rtc->rtc_ck);
  	if (ret)
-		return ret;
+		goto err;
regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, PWR_CR_DBP); @@ -595,7 +633,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)
  	 * After a system reset, RTC_ISR.INITS flag can be read to check if
  	 * the calendar has been initalized or not. INITS flag is reset by a
  	 * power-on reset (no vbat, no power-supply). It is not reset if
-	 * ck_rtc parent clock has changed (so RTC prescalers need to be
+	 * rtc_ck parent clock has changed (so RTC prescalers need to be
  	 * changed). That's why we cannot rely on this flag to know if RTC
  	 * init has to be done.
  	 */
@@ -646,7 +684,9 @@ static int stm32_rtc_probe(struct platform_device *pdev)
return 0;
  err:
-	clk_disable_unprepare(rtc->ck_rtc);
+	if (rtc->data->has_pclk)
+		clk_disable_unprepare(rtc->pclk);
+	clk_disable_unprepare(rtc->rtc_ck);
regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, 0); @@ -667,7 +707,9 @@ static int stm32_rtc_remove(struct platform_device *pdev)
  	writel_relaxed(cr, rtc->base + STM32_RTC_CR);
  	stm32_rtc_wpr_lock(rtc);
- clk_disable_unprepare(rtc->ck_rtc);
+	clk_disable_unprepare(rtc->rtc_ck);
+	if (rtc->data->has_pclk)
+		clk_disable_unprepare(rtc->pclk);
/* Enable backup domain write protection */
  	regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, 0);
@@ -682,6 +724,9 @@ static int stm32_rtc_suspend(struct device *dev)
  {
  	struct stm32_rtc *rtc = dev_get_drvdata(dev);
+ if (rtc->data->has_pclk)
+		clk_disable_unprepare(rtc->pclk);
+
  	if (device_may_wakeup(dev))
  		return enable_irq_wake(rtc->irq_alarm);
@@ -693,6 +738,12 @@ static int stm32_rtc_resume(struct device *dev)
  	struct stm32_rtc *rtc = dev_get_drvdata(dev);
  	int ret = 0;
+ if (rtc->data->has_pclk) {
+		ret = clk_prepare_enable(rtc->pclk);
+		if (ret)
+			return ret;
+	}
+
  	ret = stm32_rtc_wait_sync(rtc);
  	if (ret < 0)
  		return ret;

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