1 files changed, 87 insertions, 17 deletions

diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
index 384dca16af8b..92e1b78ff481 100644
--- a/drivers/watchdog/da9063_wdt.c
+++ b/drivers/watchdog/da9063_wdt.c
@@ -14,9 +14,11 @@
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
+#include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/mfd/da9063/registers.h>
 #include <linux/mfd/da9063/core.h>
+#include <linux/property.h>
 #include <linux/regmap.h>
 
 /*
@@ -25,6 +27,7 @@
  *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
  */
 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
+
 #define DA9063_TWDSCALE_DISABLE		0
 #define DA9063_TWDSCALE_MIN		1
 #define DA9063_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
@@ -46,15 +49,16 @@ static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
 }
 
 /*
- * Return 0 if watchdog is disabled, else non zero.
+ * Read the currently active timeout.
+ * Zero means the watchdog is disabled.
  */
-static unsigned int da9063_wdt_is_running(struct da9063 *da9063)
+static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
 {
 	unsigned int val;
 
 	regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
 
-	return val & DA9063_TWDSCALE_MASK;
+	return wdt_timeout[val & DA9063_TWDSCALE_MASK];
 }
 
 static int da9063_wdt_disable_timer(struct da9063 *da9063)
@@ -120,6 +124,13 @@ static int da9063_wdt_ping(struct watchdog_device *wdd)
 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 	int ret;
 
+	/*
+	 * Prevent pings from occurring late in system poweroff/reboot sequence
+	 * and possibly locking out restart handler from accessing i2c bus.
+	 */
+	if (system_state > SYSTEM_RUNNING)
+		return 0;
+
 	ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
 			   DA9063_WATCHDOG);
 	if (ret)
@@ -161,14 +172,28 @@ static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 			      void *data)
 {
 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
+	struct i2c_client *client = to_i2c_client(da9063->dev);
+	union i2c_smbus_data msg;
 	int ret;
 
-	ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
-			   DA9063_SHUTDOWN);
-	if (ret)
+	/*
+	 * Don't use regmap because it is not atomic safe. Additionally, use
+	 * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus
+	 * might previously be locked by some process unable to release the
+	 * lock due to interrupts already being disabled at this late stage.
+	 */
+	msg.byte = DA9063_SHUTDOWN;
+	ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
+			I2C_SMBUS_WRITE, DA9063_REG_CONTROL_F,
+			I2C_SMBUS_BYTE_DATA, &msg);
+
+	if (ret < 0)
 		dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
 			  ret);
 
+	/* wait for reset to assert... */
+	mdelay(500);
+
 	return ret;
 }
 
@@ -188,47 +213,92 @@ static const struct watchdog_ops da9063_watchdog_ops = {
 
 static int da9063_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct da9063 *da9063;
 	struct watchdog_device *wdd;
+	unsigned int timeout;
 
-	if (!pdev->dev.parent)
+	if (!dev->parent)
 		return -EINVAL;
 
-	da9063 = dev_get_drvdata(pdev->dev.parent);
+	da9063 = dev_get_drvdata(dev->parent);
 	if (!da9063)
 		return -EINVAL;
 
-	wdd = devm_kzalloc(&pdev->dev, sizeof(*wdd), GFP_KERNEL);
+	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
 	if (!wdd)
 		return -ENOMEM;
 
+	da9063->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
+
 	wdd->info = &da9063_watchdog_info;
 	wdd->ops = &da9063_watchdog_ops;
 	wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
 	wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
 	wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
-	wdd->timeout = DA9063_WDG_TIMEOUT;
-	wdd->parent = &pdev->dev;
-
+	wdd->parent = dev;
 	wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 
 	watchdog_set_restart_priority(wdd, 128);
-
 	watchdog_set_drvdata(wdd, da9063);
+	dev_set_drvdata(dev, wdd);
+
+	wdd->timeout = DA9063_WDG_TIMEOUT;
+
+	/* Use pre-configured timeout if watchdog is already running. */
+	timeout = da9063_wdt_read_timeout(da9063);
+	if (timeout)
+		wdd->timeout = timeout;
+
+	/* Set timeout, maybe override it with DT value, scale it */
+	watchdog_init_timeout(wdd, 0, dev);
+	da9063_wdt_set_timeout(wdd, wdd->timeout);
 
-	/* Change the timeout to the default value if the watchdog is running */
-	if (da9063_wdt_is_running(da9063)) {
-		da9063_wdt_update_timeout(da9063, DA9063_WDG_TIMEOUT);
+	/* Update timeout if the watchdog is already running. */
+	if (timeout) {
+		da9063_wdt_update_timeout(da9063, wdd->timeout);
 		set_bit(WDOG_HW_RUNNING, &wdd->status);
 	}
 
-	return devm_watchdog_register_device(&pdev->dev, wdd);
+	return devm_watchdog_register_device(dev, wdd);
 }
 
+static int da9063_wdt_suspend(struct device *dev)
+{
+	struct watchdog_device *wdd = dev_get_drvdata(dev);
+	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
+
+	if (!da9063->use_sw_pm)
+		return 0;
+
+	if (watchdog_active(wdd))
+		return da9063_wdt_stop(wdd);
+
+	return 0;
+}
+
+static int da9063_wdt_resume(struct device *dev)
+{
+	struct watchdog_device *wdd = dev_get_drvdata(dev);
+	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
+
+	if (!da9063->use_sw_pm)
+		return 0;
+
+	if (watchdog_active(wdd))
+		return da9063_wdt_start(wdd);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops, da9063_wdt_suspend,
+				da9063_wdt_resume);
+
 static struct platform_driver da9063_wdt_driver = {
 	.probe = da9063_wdt_probe,
 	.driver = {
 		.name = DA9063_DRVNAME_WATCHDOG,
+		.pm = pm_sleep_ptr(&da9063_wdt_pm_ops),
 	},
 };
 module_platform_driver(da9063_wdt_driver);