1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
new file mode 100644
index 000000000..426962547
--- /dev/null
+++ b/drivers/watchdog/da9062_wdt.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog device driver for DA9062 and DA9061 PMICs
+ * Copyright (C) 2015  Dialog Semiconductor Ltd.
+ *
+ */
+
+#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/jiffies.h>
+#include <linux/mfd/da9062/registers.h>
+#include <linux/mfd/da9062/core.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+
+static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
+#define DA9062_TWDSCALE_DISABLE		0
+#define DA9062_TWDSCALE_MIN		1
+#define DA9062_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
+#define DA9062_WDT_MIN_TIMEOUT		wdt_timeout[DA9062_TWDSCALE_MIN]
+#define DA9062_WDT_MAX_TIMEOUT		wdt_timeout[DA9062_TWDSCALE_MAX]
+#define DA9062_WDG_DEFAULT_TIMEOUT	wdt_timeout[DA9062_TWDSCALE_MAX-1]
+#define DA9062_RESET_PROTECTION_MS	300
+
+struct da9062_watchdog {
+	struct da9062 *hw;
+	struct watchdog_device wdtdev;
+	bool use_sw_pm;
+};
+
+static unsigned int da9062_wdt_read_timeout(struct da9062_watchdog *wdt)
+{
+	unsigned int val;
+
+	regmap_read(wdt->hw->regmap, DA9062AA_CONTROL_D, &val);
+
+	return wdt_timeout[val & DA9062AA_TWDSCALE_MASK];
+}
+
+static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
+{
+	unsigned int i;
+
+	for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
+		if (wdt_timeout[i] >= secs)
+			return i;
+	}
+
+	return DA9062_TWDSCALE_MAX;
+}
+
+static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
+{
+	return regmap_update_bits(wdt->hw->regmap, DA9062AA_CONTROL_F,
+				  DA9062AA_WATCHDOG_MASK,
+				  DA9062AA_WATCHDOG_MASK);
+}
+
+static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
+					      unsigned int regval)
+{
+	struct da9062 *chip = wdt->hw;
+
+	regmap_update_bits(chip->regmap,
+				  DA9062AA_CONTROL_D,
+				  DA9062AA_TWDSCALE_MASK,
+				  DA9062_TWDSCALE_DISABLE);
+
+	usleep_range(150, 300);
+
+	return regmap_update_bits(chip->regmap,
+				  DA9062AA_CONTROL_D,
+				  DA9062AA_TWDSCALE_MASK,
+				  regval);
+}
+
+static int da9062_wdt_start(struct watchdog_device *wdd)
+{
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+	unsigned int selector;
+	int ret;
+
+	selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
+	ret = da9062_wdt_update_timeout_register(wdt, selector);
+	if (ret)
+		dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
+			ret);
+
+	return ret;
+}
+
+static int da9062_wdt_stop(struct watchdog_device *wdd)
+{
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+	int ret;
+
+	ret = regmap_update_bits(wdt->hw->regmap,
+				 DA9062AA_CONTROL_D,
+				 DA9062AA_TWDSCALE_MASK,
+				 DA9062_TWDSCALE_DISABLE);
+	if (ret)
+		dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
+			ret);
+
+	return ret;
+}
+
+static int da9062_wdt_ping(struct watchdog_device *wdd)
+{
+	struct da9062_watchdog *wdt = 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 = da9062_reset_watchdog_timer(wdt);
+	if (ret)
+		dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
+			ret);
+
+	return ret;
+}
+
+static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
+				  unsigned int timeout)
+{
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+	unsigned int selector;
+	int ret;
+
+	selector = da9062_wdt_timeout_to_sel(timeout);
+	ret = da9062_wdt_update_timeout_register(wdt, selector);
+	if (ret)
+		dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
+			ret);
+	else
+		wdd->timeout = wdt_timeout[selector];
+
+	return ret;
+}
+
+static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
+			      void *data)
+{
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+	struct i2c_client *client = to_i2c_client(wdt->hw->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 be previously locked by some process unable to release the
+	 * lock due to interrupts already being disabled at this late stage.
+	 */
+	msg.byte = DA9062AA_SHUTDOWN_MASK;
+	ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
+			       I2C_SMBUS_WRITE, DA9062AA_CONTROL_F,
+			       I2C_SMBUS_BYTE_DATA, &msg);
+
+	if (ret < 0)
+		dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
+			  ret);
+
+	/* wait for reset to assert... */
+	mdelay(500);
+
+	return ret;
+}
+
+static const struct watchdog_info da9062_watchdog_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	.identity = "DA9062 WDT",
+};
+
+static const struct watchdog_ops da9062_watchdog_ops = {
+	.owner = THIS_MODULE,
+	.start = da9062_wdt_start,
+	.stop = da9062_wdt_stop,
+	.ping = da9062_wdt_ping,
+	.set_timeout = da9062_wdt_set_timeout,
+	.restart = da9062_wdt_restart,
+};
+
+static const struct of_device_id da9062_compatible_id_table[] = {
+	{ .compatible = "dlg,da9062-watchdog", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
+
+static int da9062_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	unsigned int timeout;
+	struct da9062 *chip;
+	struct da9062_watchdog *wdt;
+
+	chip = dev_get_drvdata(dev->parent);
+	if (!chip)
+		return -EINVAL;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
+
+	wdt->hw = chip;
+
+	wdt->wdtdev.info = &da9062_watchdog_info;
+	wdt->wdtdev.ops = &da9062_watchdog_ops;
+	wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
+	wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
+	wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
+	wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
+	wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
+	wdt->wdtdev.parent = dev;
+
+	watchdog_set_restart_priority(&wdt->wdtdev, 128);
+
+	watchdog_set_drvdata(&wdt->wdtdev, wdt);
+	dev_set_drvdata(dev, &wdt->wdtdev);
+
+	timeout = da9062_wdt_read_timeout(wdt);
+	if (timeout)
+		wdt->wdtdev.timeout = timeout;
+
+	/* Set timeout from DT value if available */
+	watchdog_init_timeout(&wdt->wdtdev, 0, dev);
+
+	if (timeout) {
+		da9062_wdt_set_timeout(&wdt->wdtdev, wdt->wdtdev.timeout);
+		set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
+	}
+
+	return devm_watchdog_register_device(dev, &wdt->wdtdev);
+}
+
+static int __maybe_unused da9062_wdt_suspend(struct device *dev)
+{
+	struct watchdog_device *wdd = dev_get_drvdata(dev);
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+
+	if (!wdt->use_sw_pm)
+		return 0;
+
+	if (watchdog_active(wdd))
+		return da9062_wdt_stop(wdd);
+
+	return 0;
+}
+
+static int __maybe_unused da9062_wdt_resume(struct device *dev)
+{
+	struct watchdog_device *wdd = dev_get_drvdata(dev);
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+
+	if (!wdt->use_sw_pm)
+		return 0;
+
+	if (watchdog_active(wdd))
+		return da9062_wdt_start(wdd);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(da9062_wdt_pm_ops,
+			 da9062_wdt_suspend, da9062_wdt_resume);
+
+static struct platform_driver da9062_wdt_driver = {
+	.probe = da9062_wdt_probe,
+	.driver = {
+		.name = "da9062-watchdog",
+		.pm = &da9062_wdt_pm_ops,
+		.of_match_table = da9062_compatible_id_table,
+	},
+};
+module_platform_driver(da9062_wdt_driver);
+
+MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
+MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9062-watchdog");