rtc: s5m: add support for S2MPG10 RTC

Add support for Samsung's S2MPG10 PMIC RTC, which is similar to the
existing PMIC RTCs supported by this driver.

S2MPG10 doesn't use I2C, so we expect the core driver to have created a
regmap for us.

Additionally, it can be used for doing a cold-reset. If requested to do
so (via DT), S2MPG10 is programmed with a watchdog configuration that
will perform a full power cycle upon watchdog expiry.

Reviewed-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: André Draszik <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

Author: andred

drivers/rtc/rtc-s5m.c

@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/i2c.h>
 #include <linux/bcd.h>
+#include <linux/reboot.h>
 #include <linux/regmap.h>
 #include <linux/rtc.h>
 #include <linux/platform_device.h>
@@ -53,6 +54,7 @@ enum {
  * Device     | Write time | Read time | Write alarm
  * =================================================
  * S5M8767    | UDR + TIME |           | UDR
+ * S2MPG10    | WUDR       | RUDR      | AUDR
  * S2MPS11/14 | WUDR       | RUDR      | WUDR + RUDR
  * S2MPS13    | WUDR       | RUDR      | WUDR + AUDR
  * S2MPS15    | WUDR       | RUDR      | AUDR
@@ -99,6 +101,20 @@ static const struct s5m_rtc_reg_config s5m_rtc_regs = {
 	.write_alarm_udr_mask	= S5M_RTC_UDR_MASK,
 };
 
+/* Register map for S2MPG10 */
+static const struct s5m_rtc_reg_config s2mpg10_rtc_regs = {
+	.regs_count		= 7,
+	.time			= S2MPG10_RTC_SEC,
+	.ctrl			= S2MPG10_RTC_CTRL,
+	.alarm0			= S2MPG10_RTC_A0SEC,
+	.alarm1			= S2MPG10_RTC_A1SEC,
+	.udr_update		= S2MPG10_RTC_UPDATE,
+	.autoclear_udr_mask	= S2MPS15_RTC_WUDR_MASK | S2MPS15_RTC_AUDR_MASK,
+	.read_time_udr_mask	= S2MPS_RTC_RUDR_MASK,
+	.write_time_udr_mask	= S2MPS15_RTC_WUDR_MASK,
+	.write_alarm_udr_mask	= S2MPS15_RTC_AUDR_MASK,
+};
+
 /* Register map for S2MPS13 */
 static const struct s5m_rtc_reg_config s2mps13_rtc_regs = {
 	.regs_count		= 7,
@@ -238,6 +254,7 @@ static int s5m_check_peding_alarm_interrupt(struct s5m_rtc_info *info,
 		ret = regmap_read(info->regmap, S5M_RTC_STATUS, &val);
 		val &= S5M_ALARM0_STATUS;
 		break;
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -300,6 +317,7 @@ static int s5m8767_rtc_set_alarm_reg(struct s5m_rtc_info *info)
 	case S5M8767X:
 		data &= ~S5M_RTC_TIME_EN_MASK;
 		break;
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -351,6 +369,7 @@ static int s5m_rtc_read_time(struct device *dev, struct rtc_time *tm)
 
 	switch (info->device_type) {
 	case S5M8767X:
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -374,6 +393,7 @@ static int s5m_rtc_set_time(struct device *dev, struct rtc_time *tm)
 
 	switch (info->device_type) {
 	case S5M8767X:
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -411,6 +431,7 @@ static int s5m_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 
 	switch (info->device_type) {
 	case S5M8767X:
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -449,6 +470,7 @@ static int s5m_rtc_stop_alarm(struct s5m_rtc_info *info)
 
 	switch (info->device_type) {
 	case S5M8767X:
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -487,6 +509,7 @@ static int s5m_rtc_start_alarm(struct s5m_rtc_info *info)
 
 	switch (info->device_type) {
 	case S5M8767X:
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -524,6 +547,7 @@ static int s5m_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 
 	switch (info->device_type) {
 	case S5M8767X:
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -604,6 +628,7 @@ static int s5m8767_rtc_init_reg(struct s5m_rtc_info *info)
 		ret = regmap_raw_write(info->regmap, S5M_ALARM0_CONF, data, 2);
 		break;
 
+	case S2MPG10:
 	case S2MPS15X:
 	case S2MPS14X:
 	case S2MPS13X:
@@ -634,6 +659,25 @@ static int s5m8767_rtc_init_reg(struct s5m_rtc_info *info)
 	return ret;
 }
 
+static int s5m_rtc_restart_s2mpg10(struct sys_off_data *data)
+{
+	struct s5m_rtc_info *info = data->cb_data;
+	int ret;
+
+	if (data->mode != REBOOT_COLD && data->mode != REBOOT_HARD)
+		return NOTIFY_DONE;
+
+	/*
+	 * Arm watchdog with maximum timeout (2 seconds), and perform full reset
+	 * on expiry.
+	 */
+	ret = regmap_set_bits(info->regmap, S2MPG10_RTC_WTSR,
+			      (S2MPG10_WTSR_COLDTIMER | S2MPG10_WTSR_COLDRST
+			       | S2MPG10_WTSR_WTSRT | S2MPG10_WTSR_WTSR_EN));
+
+	return ret ? NOTIFY_BAD : NOTIFY_DONE;
+}
+
 static int s5m_rtc_probe(struct platform_device *pdev)
 {
 	struct sec_pmic_dev *s5m87xx = dev_get_drvdata(pdev->dev.parent);
@@ -689,6 +733,9 @@ static int s5m_rtc_probe(struct platform_device *pdev)
 		if (IS_ERR(info->regmap))
 			return dev_err_probe(&pdev->dev, PTR_ERR(info->regmap),
 					     "Failed to allocate regmap\n");
+	} else if (device_type == S2MPG10) {
+		info->regs = &s2mpg10_rtc_regs;
+		alarm_irq = S2MPG10_IRQ_RTCA0;
 	} else {
 		return dev_err_probe(&pdev->dev, -ENODEV,
 				     "Unsupported device type %d\n",
@@ -735,6 +782,18 @@ static int s5m_rtc_probe(struct platform_device *pdev)
 		device_init_wakeup(&pdev->dev, true);
 	}
 
+	if (of_device_is_system_power_controller(pdev->dev.parent->of_node) &&
+	    info->device_type == S2MPG10) {
+		ret = devm_register_sys_off_handler(&pdev->dev,
+						    SYS_OFF_MODE_RESTART,
+						    SYS_OFF_PRIO_HIGH + 1,
+						    s5m_rtc_restart_s2mpg10,
+						    info);
+		if (ret)
+			return dev_err_probe(&pdev->dev, ret,
+				       "Failed to register restart handler\n");
+	}
+
 	return devm_rtc_register_device(info->rtc_dev);
 }
 
@@ -766,6 +825,7 @@ static SIMPLE_DEV_PM_OPS(s5m_rtc_pm_ops, s5m_rtc_suspend, s5m_rtc_resume);
 
 static const struct platform_device_id s5m_rtc_id[] = {
 	{ "s5m-rtc",		S5M8767X },
+	{ "s2mpg10-rtc",	S2MPG10 },
 	{ "s2mps13-rtc",	S2MPS13X },
 	{ "s2mps14-rtc",	S2MPS14X },
 	{ "s2mps15-rtc",	S2MPS15X },