Merge tag 'rtc-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

Pull RTC updates from Alexandre Belloni:
 "Subsystem:

   - Add a way for drivers to tell the core the supported alarm range is
     smaller than the date range. This is not used yet but will be
     useful for the alarmtimers in the next release.

   - fix Wvoid-pointer-to-enum-cast warnings

   - remove redundant of_match_ptr()

   - stop warning for invalid alarms when the alarm is disabled

  Drivers:

   - isl12022: allow setting the trip level for battery level detection

   - pcf2127: add support for PCF2131 and multiple timestamps

   - stm32: time precision improvement, many fixes

   - twl: NVRAM support"

* tag 'rtc-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (73 commits)
  dt-bindings: rtc: ds3231: Remove text binding
  rtc: wm8350: remove unnecessary messages
  rtc: twl: remove unnecessary messages
  rtc: sun6i: remove unnecessary message
  rtc: stop warning for invalid alarms when the alarm is disabled
  rtc: twl: add NVRAM support
  rtc: pcf85363: Allow to wake up system without IRQ
  rtc: m48t86: add DT support for m48t86
  dt-bindings: rtc: Add ST M48T86
  rtc: pcf2127: remove useless check
  rtc: rzn1: Report maximum alarm limit to rtc core
  rtc: ds1305: Report maximum alarm limit to rtc core
  rtc: tps6586x: Report maximum alarm limit to rtc core
  rtc: cmos: Report supported alarm limit to rtc infrastructure
  rtc: cros-ec: Detect and report supported alarm window size
  rtc: Add support for limited alarm timer offsets
  rtc: isl1208: Fix incorrect logic in isl1208_set_xtoscb()
  MAINTAINERS: remove obsolete pattern in RTC SUBSYSTEM section
  rtc: tps65910: Remove redundant dev_warn() and do not check for 0 return after calling platform_get_irq()
  rtc: omap: Do not check for 0 return after calling platform_get_irq()
  ...

1 files changed, 87 insertions, 56 deletions

diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
index 3d36e11cff80..76753c71d92e 100644
--- a/drivers/rtc/rtc-stm32.c
+++ b/drivers/rtc/rtc-stm32.c
@@ -6,11 +6,13 @@
 
 #include <linux/bcd.h>
 #include <linux/clk.h>
+#include <linux/errno.h>
 #include <linux/iopoll.h>
 #include <linux/ioport.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
-#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
 #include <linux/pm_wakeirq.h>
 #include <linux/regmap.h>
 #include <linux/rtc.h>
@@ -89,6 +91,9 @@
 /* Max STM32 RTC register offset is 0x3FC */
 #define UNDEF_REG			0xFFFF
 
+/* STM32 RTC driver time helpers */
+#define SEC_PER_DAY		(24 * 60 * 60)
+
 struct stm32_rtc;
 
 struct stm32_rtc_registers {
@@ -114,6 +119,7 @@ struct stm32_rtc_data {
 	void (*clear_events)(struct stm32_rtc *rtc, unsigned int flags);
 	bool has_pclk;
 	bool need_dbp;
+	bool need_accuracy;
 };
 
 struct stm32_rtc {
@@ -158,10 +164,9 @@ static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
 		 * 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(
-					rtc->base + regs->isr,
-					isr, (isr & STM32_RTC_ISR_INITF),
-					10, 100000);
+		return readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr, isr,
+							 (isr & STM32_RTC_ISR_INITF),
+							 10, 100000);
 	}
 
 	return 0;
@@ -425,40 +430,42 @@ static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 	return 0;
 }
 
-static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm)
+static int stm32_rtc_valid_alrm(struct device *dev, struct rtc_time *tm)
 {
-	const struct stm32_rtc_registers *regs = &rtc->data->regs;
-	int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec;
-	unsigned int dr = readl_relaxed(rtc->base + regs->dr);
-	unsigned int tr = readl_relaxed(rtc->base + regs->tr);
-
-	cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
-	cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
-	cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
-	cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
-	cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
-	cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
+	static struct rtc_time now;
+	time64_t max_alarm_time64;
+	int max_day_forward;
+	int next_month;
+	int next_year;
 
 	/*
 	 * Assuming current date is M-D-Y H:M:S.
 	 * RTC alarm can't be set on a specific month and year.
 	 * So the valid alarm range is:
 	 *	M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S
-	 * with a specific case for December...
 	 */
-	if ((((tm->tm_year > cur_year) &&
-	      (tm->tm_mon == 0x1) && (cur_mon == 0x12)) ||
-	     ((tm->tm_year == cur_year) &&
-	      (tm->tm_mon <= cur_mon + 1))) &&
-	    ((tm->tm_mday > cur_day) ||
-	     ((tm->tm_mday == cur_day) &&
-	     ((tm->tm_hour > cur_hour) ||
-	      ((tm->tm_hour == cur_hour) && (tm->tm_min > cur_min)) ||
-	      ((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) &&
-	       (tm->tm_sec >= cur_sec))))))
-		return 0;
+	stm32_rtc_read_time(dev, &now);
+
+	/*
+	 * Find the next month and the year of the next month.
+	 * Note: tm_mon and next_month are from 0 to 11
+	 */
+	next_month = now.tm_mon + 1;
+	if (next_month == 12) {
+		next_month = 0;
+		next_year = now.tm_year + 1;
+	} else {
+		next_year = now.tm_year;
+	}
 
-	return -EINVAL;
+	/* Find the maximum limit of alarm in days. */
+	max_day_forward = rtc_month_days(now.tm_mon, now.tm_year)
+			 - now.tm_mday
+			 + min(rtc_month_days(next_month, next_year), now.tm_mday);
+
+	/* Convert to timestamp and compare the alarm time and its upper limit */
+	max_alarm_time64 = rtc_tm_to_time64(&now) + max_day_forward * SEC_PER_DAY;
+	return rtc_tm_to_time64(tm) <= max_alarm_time64 ? 0 : -EINVAL;
 }
 
 static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
@@ -469,17 +476,17 @@ static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	unsigned int cr, isr, alrmar;
 	int ret = 0;
 
-	tm2bcd(tm);
-
 	/*
 	 * RTC alarm can't be set on a specific date, unless this date is
 	 * up to the same day of month next month.
 	 */
-	if (stm32_rtc_valid_alrm(rtc, tm) < 0) {
+	if (stm32_rtc_valid_alrm(dev, tm) < 0) {
 		dev_err(dev, "Alarm can be set only on upcoming month.\n");
 		return -EINVAL;
 	}
 
+	tm2bcd(tm);
+
 	alrmar = 0;
 	/* tm_year and tm_mon are not used because not supported by RTC */
 	alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) &
@@ -545,6 +552,7 @@ static void stm32_rtc_clear_events(struct stm32_rtc *rtc,
 static const struct stm32_rtc_data stm32_rtc_data = {
 	.has_pclk = false,
 	.need_dbp = true,
+	.need_accuracy = false,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -566,6 +574,7 @@ static const struct stm32_rtc_data stm32_rtc_data = {
 static const struct stm32_rtc_data stm32h7_rtc_data = {
 	.has_pclk = true,
 	.need_dbp = true,
+	.need_accuracy = false,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -596,6 +605,7 @@ static void stm32mp1_rtc_clear_events(struct stm32_rtc *rtc,
 static const struct stm32_rtc_data stm32mp1_data = {
 	.has_pclk = true,
 	.need_dbp = false,
+	.need_accuracy = true,
 	.regs = {
 		.tr = 0x00,
 		.dr = 0x04,
@@ -628,7 +638,7 @@ static int stm32_rtc_init(struct platform_device *pdev,
 	const struct stm32_rtc_registers *regs = &rtc->data->regs;
 	unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr;
 	unsigned int rate;
-	int ret = 0;
+	int ret;
 
 	rate = clk_get_rate(rtc->rtc_ck);
 
@@ -636,18 +646,32 @@ static int stm32_rtc_init(struct platform_device *pdev,
 	pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT;
 	pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT;
 
-	for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) {
-		pred_s = (rate / (pred_a + 1)) - 1;
+	if (rate > (pred_a_max + 1) * (pred_s_max + 1)) {
+		dev_err(&pdev->dev, "rtc_ck rate is too high: %dHz\n", rate);
+		return -EINVAL;
+	}
+
+	if (rtc->data->need_accuracy) {
+		for (pred_a = 0; pred_a <= pred_a_max; pred_a++) {
+			pred_s = (rate / (pred_a + 1)) - 1;
+
+			if (pred_s <= pred_s_max && ((pred_s + 1) * (pred_a + 1)) == rate)
+				break;
+		}
+	} else {
+		for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) {
+			pred_s = (rate / (pred_a + 1)) - 1;
 
-		if (((pred_s + 1) * (pred_a + 1)) == rate)
-			break;
+			if (((pred_s + 1) * (pred_a + 1)) == rate)
+				break;
+		}
 	}
 
 	/*
 	 * Can't find a 1Hz, so give priority to RTC power consumption
 	 * by choosing the higher possible value for prediv_a
 	 */
-	if ((pred_s > pred_s_max) || (pred_a > pred_a_max)) {
+	if (pred_s > pred_s_max || pred_a > pred_a_max) {
 		pred_a = pred_a_max;
 		pred_s = (rate / (pred_a + 1)) - 1;
 
@@ -656,6 +680,20 @@ static int stm32_rtc_init(struct platform_device *pdev,
 			 "fast" : "slow");
 	}
 
+	cr = readl_relaxed(rtc->base + regs->cr);
+
+	prer = readl_relaxed(rtc->base + regs->prer);
+	prer &= STM32_RTC_PRER_PRED_S | STM32_RTC_PRER_PRED_A;
+
+	pred_s = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) &
+		 STM32_RTC_PRER_PRED_S;
+	pred_a = (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) &
+		 STM32_RTC_PRER_PRED_A;
+
+	/* quit if there is nothing to initialize */
+	if ((cr & STM32_RTC_CR_FMT) == 0 && prer == (pred_s | pred_a))
+		return 0;
+
 	stm32_rtc_wpr_unlock(rtc);
 
 	ret = stm32_rtc_enter_init_mode(rtc);
@@ -665,13 +703,10 @@ static int stm32_rtc_init(struct platform_device *pdev,
 		goto end;
 	}
 
-	prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S;
-	writel_relaxed(prer, rtc->base + regs->prer);
-	prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A;
-	writel_relaxed(prer, rtc->base + regs->prer);
+	writel_relaxed(pred_s, rtc->base + regs->prer);
+	writel_relaxed(pred_a | pred_s, rtc->base + regs->prer);
 
 	/* Force 24h time format */
-	cr = readl_relaxed(rtc->base + regs->cr);
 	cr &= ~STM32_RTC_CR_FMT;
 	writel_relaxed(cr, rtc->base + regs->cr);
 
@@ -730,16 +765,13 @@ static int stm32_rtc_probe(struct platform_device *pdev)
 		rtc->rtc_ck = devm_clk_get(&pdev->dev, NULL);
 	} else {
 		rtc->pclk = devm_clk_get(&pdev->dev, "pclk");
-		if (IS_ERR(rtc->pclk)) {
-			dev_err(&pdev->dev, "no pclk clock");
-			return PTR_ERR(rtc->pclk);
-		}
+		if (IS_ERR(rtc->pclk))
+			return dev_err_probe(&pdev->dev, PTR_ERR(rtc->pclk), "no pclk clock");
+
 		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);
-	}
+	if (IS_ERR(rtc->rtc_ck))
+		return dev_err_probe(&pdev->dev, PTR_ERR(rtc->rtc_ck), "no rtc_ck clock");
 
 	if (rtc->data->has_pclk) {
 		ret = clk_prepare_enable(rtc->pclk);
@@ -859,7 +891,6 @@ static void stm32_rtc_remove(struct platform_device *pdev)
 	device_init_wakeup(&pdev->dev, false);
 }
 
-#ifdef CONFIG_PM_SLEEP
 static int stm32_rtc_suspend(struct device *dev)
 {
 	struct stm32_rtc *rtc = dev_get_drvdata(dev);
@@ -890,10 +921,10 @@ static int stm32_rtc_resume(struct device *dev)
 
 	return ret;
 }
-#endif
 
-static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops,
-			 stm32_rtc_suspend, stm32_rtc_resume);
+static const struct dev_pm_ops stm32_rtc_pm_ops = {
+	NOIRQ_SYSTEM_SLEEP_PM_OPS(stm32_rtc_suspend, stm32_rtc_resume)
+};
 
 static struct platform_driver stm32_rtc_driver = {
 	.probe		= stm32_rtc_probe,