1 files changed, 198 insertions, 0 deletions

diff --git a/drivers/watchdog/rn5t618_wdt.c b/drivers/watchdog/rn5t618_wdt.c
new file mode 100644
index 000000000000..d1c12278cb6a
--- /dev/null
+++ b/drivers/watchdog/rn5t618_wdt.c
@@ -0,0 +1,198 @@
+/*
+ * 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");