--- /dev/null
+/*
+ * Watchdog driver for Ricoh RN5T618 PMIC
+ *
+ * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/device.h>
+#include <linux/mfd/rn5t618.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define DRIVER_NAME "rn5t618-wdt"
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static unsigned int timeout;
+
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct rn5t618_wdt {
+ struct watchdog_device wdt_dev;
+ struct rn5t618 *rn5t618;
+};
+
+/*
+ * This array encodes the values of WDOGTIM field for the supported
+ * watchdog expiration times. If the watchdog is not accessed before
+ * the timer expiration, the PMU generates an interrupt and if the CPU
+ * doesn't clear it within one second the system is restarted.
+ */
+static const struct {
+ u8 reg_val;
+ unsigned int time;
+} rn5t618_wdt_map[] = {
+ { 0, 1 },
+ { 1, 8 },
+ { 2, 32 },
+ { 3, 128 },
+};
+
+static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
+ unsigned int t)
+{
+ struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+ int ret, i;
+
+ for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
+ if (rn5t618_wdt_map[i].time + 1 >= t)
+ break;
+ }
+
+ if (i == ARRAY_SIZE(rn5t618_wdt_map))
+ return -EINVAL;
+
+ ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
+ RN5T618_WATCHDOG_WDOGTIM_M,
+ rn5t618_wdt_map[i].reg_val);
+ if (!ret)
+ wdt_dev->timeout = rn5t618_wdt_map[i].time;
+
+ return ret;
+}
+
+static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
+{
+ struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+ int ret;
+
+ ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
+ if (ret)
+ return ret;
+
+ /* enable repower-on */
+ ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
+ RN5T618_REPCNT_REPWRON,
+ RN5T618_REPCNT_REPWRON);
+ if (ret)
+ return ret;
+
+ /* enable watchdog */
+ ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
+ RN5T618_WATCHDOG_WDOGEN,
+ RN5T618_WATCHDOG_WDOGEN);
+ if (ret)
+ return ret;
+
+ /* enable watchdog interrupt */
+ return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
+ RN5T618_PWRIRQ_IR_WDOG,
+ RN5T618_PWRIRQ_IR_WDOG);
+}
+
+static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
+{
+ struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+
+ return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
+ RN5T618_WATCHDOG_WDOGEN, 0);
+}
+
+static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
+{
+ struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
+ unsigned int val;
+ int ret;
+
+ /* The counter is restarted after a R/W access to watchdog register */
+ ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val);
+ if (ret)
+ return ret;
+
+ /* Clear pending watchdog interrupt */
+ return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ,
+ RN5T618_PWRIRQ_IR_WDOG, 0);
+}
+
+static struct watchdog_info rn5t618_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
+ .identity = DRIVER_NAME,
+};
+
+static struct watchdog_ops rn5t618_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = rn5t618_wdt_start,
+ .stop = rn5t618_wdt_stop,
+ .ping = rn5t618_wdt_ping,
+ .set_timeout = rn5t618_wdt_set_timeout,
+};
+
+static int rn5t618_wdt_probe(struct platform_device *pdev)
+{
+ struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
+ struct rn5t618_wdt *wdt;
+ int min_timeout, max_timeout;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ min_timeout = rn5t618_wdt_map[0].time;
+ max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;
+
+ wdt->rn5t618 = rn5t618;
+ wdt->wdt_dev.info = &rn5t618_wdt_info;
+ wdt->wdt_dev.ops = &rn5t618_wdt_ops;
+ wdt->wdt_dev.min_timeout = min_timeout;
+ wdt->wdt_dev.max_timeout = max_timeout;
+ wdt->wdt_dev.timeout = max_timeout;
+ wdt->wdt_dev.parent = &pdev->dev;
+
+ watchdog_set_drvdata(&wdt->wdt_dev, wdt);
+ watchdog_init_timeout(&wdt->wdt_dev, timeout, &pdev->dev);
+ watchdog_set_nowayout(&wdt->wdt_dev, nowayout);
+
+ platform_set_drvdata(pdev, wdt);
+
+ return watchdog_register_device(&wdt->wdt_dev);
+}
+
+static int rn5t618_wdt_remove(struct platform_device *pdev)
+{
+ struct rn5t618_wdt *wdt = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&wdt->wdt_dev);
+
+ return 0;
+}
+
+static struct platform_driver rn5t618_wdt_driver = {
+ .probe = rn5t618_wdt_probe,
+ .remove = rn5t618_wdt_remove,
+ .driver = {
+ .name = DRIVER_NAME,
+ },
+};
+
+module_platform_driver(rn5t618_wdt_driver);
+
+MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
+MODULE_DESCRIPTION("RN5T618 watchdog driver");
+MODULE_LICENSE("GPL v2");
projects / linux.git / commitdiff