watchdog: DA9055 Watchdog driver

This is the Watchdog patch for the DA9055 PMIC. This patch has got dependency on
the DA9055 MFD core.

This patch is functionally tested on SMDK6410

Signed-off-by: David Dajun Chen <dchen@diasemi.com>
Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 216 insertions, 0 deletions

diff --git a/drivers/watchdog/da9055_wdt.c b/drivers/watchdog/da9055_wdt.c
new file mode 100644
index 000000000000..709ea1aefebb
--- /dev/null
+++ b/drivers/watchdog/da9055_wdt.c
@@ -0,0 +1,216 @@
+/*
+ * System monitoring driver for DA9055 PMICs.
+ *
+ * Copyright(c) 2012 Dialog Semiconductor Ltd.
+ *
+ * Author: David Dajun Chen <dchen@diasemi.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/delay.h>
+
+#include <linux/mfd/da9055/core.h>
+#include <linux/mfd/da9055/reg.h>
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+                 "Watchdog cannot be stopped once started (default="
+                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+#define DA9055_DEF_TIMEOUT      4
+#define DA9055_TWDMIN           256
+
+struct da9055_wdt_data {
+        struct watchdog_device wdt;
+        struct da9055 *da9055;
+        struct kref kref;
+};
+
+static const struct {
+        u8 reg_val;
+        int user_time;  /* In seconds */
+} da9055_wdt_maps[] = {
+        { 0, 0 },
+        { 1, 2 },
+        { 2, 4 },
+        { 3, 8 },
+        { 4, 16 },
+        { 5, 32 },
+        { 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
+        { 6, 65 },
+        { 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
+        { 7, 131 },
+};
+
+static int da9055_wdt_set_timeout(struct watchdog_device *wdt_dev,
+                                  unsigned int timeout)
+{
+        struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+        struct da9055 *da9055 = driver_data->da9055;
+        int ret, i;
+
+        for (i = 0; i < ARRAY_SIZE(da9055_wdt_maps); i++)
+                if (da9055_wdt_maps[i].user_time == timeout)
+                        break;
+
+        if (i == ARRAY_SIZE(da9055_wdt_maps))
+                ret = -EINVAL;
+        else
+                ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
+                                        DA9055_TWDSCALE_MASK,
+                                        da9055_wdt_maps[i].reg_val <<
+                                        DA9055_TWDSCALE_SHIFT);
+        if (ret < 0)
+                dev_err(da9055->dev,
+                        "Failed to update timescale bit, %d\n", ret);
+
+        wdt_dev->timeout = timeout;
+
+        return ret;
+}
+
+static int da9055_wdt_ping(struct watchdog_device *wdt_dev)
+{
+        struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+        struct da9055 *da9055 = driver_data->da9055;
+        int ret;
+
+        /*
+         * We have a minimum time for watchdog window called TWDMIN. A write
+         * to the watchdog before this elapsed time will cause an error.
+         */
+        mdelay(DA9055_TWDMIN);
+
+        /* Reset the watchdog timer */
+        ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
+                                DA9055_WATCHDOG_MASK, 1);
+
+        return ret;
+}
+
+static void da9055_wdt_release_resources(struct kref *r)
+{
+        struct da9055_wdt_data *driver_data =
+                container_of(r, struct da9055_wdt_data, kref);
+
+        kfree(driver_data);
+}
+
+static void da9055_wdt_ref(struct watchdog_device *wdt_dev)
+{
+        struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+
+        kref_get(&driver_data->kref);
+}
+
+static void da9055_wdt_unref(struct watchdog_device *wdt_dev)
+{
+        struct da9055_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+
+        kref_put(&driver_data->kref, da9055_wdt_release_resources);
+}
+
+static int da9055_wdt_start(struct watchdog_device *wdt_dev)
+{
+        return da9055_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
+}
+
+static int da9055_wdt_stop(struct watchdog_device *wdt_dev)
+{
+        return da9055_wdt_set_timeout(wdt_dev, 0);
+}
+
+static struct watchdog_info da9055_wdt_info = {
+        .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+        .identity       = "DA9055 Watchdog",
+};
+
+static const struct watchdog_ops da9055_wdt_ops = {
+        .owner = THIS_MODULE,
+        .start = da9055_wdt_start,
+        .stop = da9055_wdt_stop,
+        .ping = da9055_wdt_ping,
+        .set_timeout = da9055_wdt_set_timeout,
+        .ref = da9055_wdt_ref,
+        .unref = da9055_wdt_unref,
+};
+
+static int da9055_wdt_probe(struct platform_device *pdev)
+{
+        struct da9055 *da9055 = dev_get_drvdata(pdev->dev.parent);
+        struct da9055_wdt_data *driver_data;
+        struct watchdog_device *da9055_wdt;
+        int ret;
+
+        driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
+                                   GFP_KERNEL);
+        if (!driver_data) {
+                dev_err(da9055->dev, "Failed to allocate watchdog device\n");
+                return -ENOMEM;
+        }
+
+        driver_data->da9055 = da9055;
+
+        da9055_wdt = &driver_data->wdt;
+
+        da9055_wdt->timeout = DA9055_DEF_TIMEOUT;
+        da9055_wdt->info = &da9055_wdt_info;
+        da9055_wdt->ops = &da9055_wdt_ops;
+        watchdog_set_nowayout(da9055_wdt, nowayout);
+        watchdog_set_drvdata(da9055_wdt, driver_data);
+
+        kref_init(&driver_data->kref);
+
+        ret = da9055_wdt_stop(da9055_wdt);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Failed to stop watchdog, %d\n", ret);
+                goto err;
+        }
+
+        dev_set_drvdata(&pdev->dev, driver_data);
+
+        ret = watchdog_register_device(&driver_data->wdt);
+        if (ret != 0)
+                dev_err(da9055->dev, "watchdog_register_device() failed: %d\n",
+                        ret);
+
+err:
+        return ret;
+}
+
+static int da9055_wdt_remove(struct platform_device *pdev)
+{
+        struct da9055_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);
+
+        watchdog_unregister_device(&driver_data->wdt);
+        kref_put(&driver_data->kref, da9055_wdt_release_resources);
+
+        return 0;
+}
+
+static struct platform_driver da9055_wdt_driver = {
+        .probe = da9055_wdt_probe,
+        .remove = da9055_wdt_remove,
+        .driver = {
+                .name   = "da9055-watchdog",
+        },
+};
+
+module_platform_driver(da9055_wdt_driver);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
+MODULE_DESCRIPTION("DA9055 watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9055-watchdog");