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Diffstat (limited to 'drivers/watchdog/da9063_wdt.c')
-rw-r--r--drivers/watchdog/da9063_wdt.c308
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);