watchdog: introduce retu_wdt driver

Introduce Retu watchdog driver.

Cc: linux-watchdog@vger.kernel.org
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

3 files changed, 191 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index bb74186d88f3..7f61687504b7 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -377,6 +377,18 @@ config UX500_WATCHDOG
           To compile this driver as a module, choose M here: the
           module will be called ux500_wdt.
 
+config RETU_WATCHDOG
+        tristate "Retu watchdog"
+        depends on MFD_RETU
+        select WATCHDOG_CORE
+        help
+          Retu watchdog driver for Nokia Internet Tablets (770, N800,
+          N810). At least on N800 the watchdog cannot be disabled, so
+          this driver is essential and you should enable it.
+
+          To compile this driver as a module, choose M here: the
+          module will be called retu_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index bec86ee6e9e3..f7a612c0a5b4 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
 obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
 obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
 obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
+obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/retu_wdt.c b/drivers/watchdog/retu_wdt.c
new file mode 100644
index 000000000000..f53615dc633d
--- /dev/null
+++ b/drivers/watchdog/retu_wdt.c
@@ -0,0 +1,178 @@
+/*
+ * Retu watchdog driver
+ *
+ * Copyright (C) 2004, 2005 Nokia Corporation
+ *
+ * Based on code written by Amit Kucheria and Michael Buesch.
+ * Rewritten by Aaro Koskinen.
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/retu.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+
+/* Watchdog timer values in seconds */
+#define RETU_WDT_MAX_TIMER      63
+
+struct retu_wdt_dev {
+        struct retu_dev         *rdev;
+        struct device           *dev;
+        struct delayed_work     ping_work;
+};
+
+/*
+ * Since Retu watchdog cannot be disabled in hardware, we must kick it
+ * with a timer until userspace watchdog software takes over. If
+ * CONFIG_WATCHDOG_NOWAYOUT is set, we never start the feeding.
+ */
+static void retu_wdt_ping_enable(struct retu_wdt_dev *wdev)
+{
+        retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
+        schedule_delayed_work(&wdev->ping_work,
+                        round_jiffies_relative(RETU_WDT_MAX_TIMER * HZ / 2));
+}
+
+static void retu_wdt_ping_disable(struct retu_wdt_dev *wdev)
+{
+        retu_write(wdev->rdev, RETU_REG_WATCHDOG, RETU_WDT_MAX_TIMER);
+        cancel_delayed_work_sync(&wdev->ping_work);
+}
+
+static void retu_wdt_ping_work(struct work_struct *work)
+{
+        struct retu_wdt_dev *wdev = container_of(to_delayed_work(work),
+                                                struct retu_wdt_dev, ping_work);
+        retu_wdt_ping_enable(wdev);
+}
+
+static int retu_wdt_start(struct watchdog_device *wdog)
+{
+        struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
+
+        retu_wdt_ping_disable(wdev);
+
+        return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
+}
+
+static int retu_wdt_stop(struct watchdog_device *wdog)
+{
+        struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
+
+        retu_wdt_ping_enable(wdev);
+
+        return 0;
+}
+
+static int retu_wdt_ping(struct watchdog_device *wdog)
+{
+        struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
+
+        return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
+}
+
+static int retu_wdt_set_timeout(struct watchdog_device *wdog,
+                                unsigned int timeout)
+{
+        struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
+
+        wdog->timeout = timeout;
+        return retu_write(wdev->rdev, RETU_REG_WATCHDOG, wdog->timeout);
+}
+
+static const struct watchdog_info retu_wdt_info = {
+        .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+        .identity = "Retu watchdog",
+};
+
+static const struct watchdog_ops retu_wdt_ops = {
+        .owner          = THIS_MODULE,
+        .start          = retu_wdt_start,
+        .stop           = retu_wdt_stop,
+        .ping           = retu_wdt_ping,
+        .set_timeout    = retu_wdt_set_timeout,
+};
+
+static int retu_wdt_probe(struct platform_device *pdev)
+{
+        struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
+        bool nowayout = WATCHDOG_NOWAYOUT;
+        struct watchdog_device *retu_wdt;
+        struct retu_wdt_dev *wdev;
+        int ret;
+
+        retu_wdt = devm_kzalloc(&pdev->dev, sizeof(*retu_wdt), GFP_KERNEL);
+        if (!retu_wdt)
+                return -ENOMEM;
+
+        wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
+        if (!wdev)
+                return -ENOMEM;
+
+        retu_wdt->info          = &retu_wdt_info;
+        retu_wdt->ops           = &retu_wdt_ops;
+        retu_wdt->timeout       = RETU_WDT_MAX_TIMER;
+        retu_wdt->min_timeout   = 0;
+        retu_wdt->max_timeout   = RETU_WDT_MAX_TIMER;
+
+        watchdog_set_drvdata(retu_wdt, wdev);
+        watchdog_set_nowayout(retu_wdt, nowayout);
+
+        wdev->rdev              = rdev;
+        wdev->dev               = &pdev->dev;
+
+        INIT_DELAYED_WORK(&wdev->ping_work, retu_wdt_ping_work);
+
+        ret = watchdog_register_device(retu_wdt);
+        if (ret < 0)
+                return ret;
+
+        if (nowayout)
+                retu_wdt_ping(retu_wdt);
+        else
+                retu_wdt_ping_enable(wdev);
+
+        platform_set_drvdata(pdev, retu_wdt);
+
+        return 0;
+}
+
+static int retu_wdt_remove(struct platform_device *pdev)
+{
+        struct watchdog_device *wdog = platform_get_drvdata(pdev);
+        struct retu_wdt_dev *wdev = watchdog_get_drvdata(wdog);
+
+        watchdog_unregister_device(wdog);
+        cancel_delayed_work_sync(&wdev->ping_work);
+
+        return 0;
+}
+
+static struct platform_driver retu_wdt_driver = {
+        .probe          = retu_wdt_probe,
+        .remove         = retu_wdt_remove,
+        .driver         = {
+                .name   = "retu-wdt",
+        },
+};
+module_platform_driver(retu_wdt_driver);
+
+MODULE_ALIAS("platform:retu-wdt");
+MODULE_DESCRIPTION("Retu watchdog");
+MODULE_AUTHOR("Amit Kucheria");
+MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
+MODULE_LICENSE("GPL");