[PATCH 2/2] rtc: stm32: add STM32H7 RTC support
Amelie DELAUNAY
amelie.delaunay at st.com
Wed Jul 5 07:19:47 PDT 2017
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 at st.com>
> ---
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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