1 files changed, 308 insertions, 0 deletions
diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
new file mode 100644
index 0000000000..684667469b
--- /dev/null
+++ b/drivers/watchdog/da9063_wdt.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for DA9063 PMICs.
+ *
+ * Copyright(c) 2012 Dialog Semiconductor Ltd.
+ *
+ * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#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>
+
+/*
+ * Watchdog selector to timeout in seconds.
+ *   0: WDT disabled;
+ *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
+ */
+static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
+static bool use_sw_pm;
+
+#define DA9063_TWDSCALE_DISABLE		0
+#define DA9063_TWDSCALE_MIN		1
+#define DA9063_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
+#define DA9063_WDT_MIN_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MIN]
+#define DA9063_WDT_MAX_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MAX]
+#define DA9063_WDG_TIMEOUT		wdt_timeout[3]
+#define DA9063_RESET_PROTECTION_MS	256
+
+static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
+{
+	unsigned int i;
+
+	for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
+		if (wdt_timeout[i] >= secs)
+			return i;
+	}
+
+	return DA9063_TWDSCALE_MAX;
+}
+
+/*
+ * Read the currently active timeout.
+ * Zero means the watchdog is disabled.
+ */
+static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
+{
+	unsigned int val;
+
+	regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
+
+	return wdt_timeout[val & DA9063_TWDSCALE_MASK];
+}
+
+static int da9063_wdt_disable_timer(struct da9063 *da9063)
+{
+	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
+				  DA9063_TWDSCALE_MASK,
+				  DA9063_TWDSCALE_DISABLE);
+}
+
+static int
+da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
+{
+	unsigned int regval;
+	int ret;
+
+	/*
+	 * The watchdog triggers a reboot if a timeout value is already
+	 * programmed because the timeout value combines two functions
+	 * in one: indicating the counter limit and starting the watchdog.
+	 * The watchdog must be disabled to be able to change the timeout
+	 * value if the watchdog is already running. Then we can set the
+	 * new timeout value which enables the watchdog again.
+	 */
+	ret = da9063_wdt_disable_timer(da9063);
+	if (ret)
+		return ret;
+
+	usleep_range(150, 300);
+	regval = da9063_wdt_timeout_to_sel(timeout);
+
+	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
+				  DA9063_TWDSCALE_MASK, regval);
+}
+
+static int da9063_wdt_start(struct watchdog_device *wdd)
+{
+	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
+	int ret;
+
+	ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
+	if (ret)
+		dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
+			ret);
+
+	return ret;
+}
+
+static int da9063_wdt_stop(struct watchdog_device *wdd)
+{
+	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
+	int ret;
+
+	ret = da9063_wdt_disable_timer(da9063);
+	if (ret)
+		dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
+			  ret);
+
+	return ret;
+}
+
+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)
+		dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
+			  ret);
+
+	return ret;
+}
+
+static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
+				  unsigned int timeout)
+{
+	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
+	int ret = 0;
+
+	/*
+	 * There are two cases when a set_timeout() will be called:
+	 * 1. The watchdog is off and someone wants to set the timeout for the
+	 *    further use.
+	 * 2. The watchdog is already running and a new timeout value should be
+	 *    set.
+	 *
+	 * The watchdog can't store a timeout value not equal zero without
+	 * enabling the watchdog, so the timeout must be buffered by the driver.
+	 */
+	if (watchdog_active(wdd))
+		ret = da9063_wdt_update_timeout(da9063, timeout);
+
+	if (ret)
+		dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
+			ret);
+	else
+		wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
+
+	return ret;
+}
+
+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;
+
+	/*
+	 * 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;
+}
+
+static const struct watchdog_info da9063_watchdog_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	.identity = "DA9063 Watchdog",
+};
+
+static const struct watchdog_ops da9063_watchdog_ops = {
+	.owner = THIS_MODULE,
+	.start = da9063_wdt_start,
+	.stop = da9063_wdt_stop,
+	.ping = da9063_wdt_ping,
+	.set_timeout = da9063_wdt_set_timeout,
+	.restart = da9063_wdt_restart,
+};
+
+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 (!dev->parent)
+		return -EINVAL;
+
+	da9063 = dev_get_drvdata(dev->parent);
+	if (!da9063)
+		return -EINVAL;
+
+	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
+	if (!wdd)
+		return -ENOMEM;
+
+	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->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);
+
+	/* 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(dev, wdd);
+}
+
+static int __maybe_unused da9063_wdt_suspend(struct device *dev)
+{
+	struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+	if (!use_sw_pm)
+		return 0;
+
+	if (watchdog_active(wdd))
+		return da9063_wdt_stop(wdd);
+
+	return 0;
+}
+
+static int __maybe_unused da9063_wdt_resume(struct device *dev)
+{
+	struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+	if (!use_sw_pm)
+		return 0;
+
+	if (watchdog_active(wdd))
+		return da9063_wdt_start(wdd);
+
+	return 0;
+}
+
+static 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 = &da9063_wdt_pm_ops,
+	},
+};
+module_platform_driver(da9063_wdt_driver);
+
+MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
+MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);