Watchdog: DA9052/53 PMIC watchdog support

This driver adds support for the watchdog functionality provided by
the Dialog Semiconductor DA9052 PMIC chip.

Tested on samsung smdkv6410 and i.mx53 QS boards.

Signed-off-by: Anthony Olech <Anthony.Olech@diasemi.com>
Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 251 insertions, 0 deletions

diff --git a/drivers/watchdog/da9052_wdt.c b/drivers/watchdog/da9052_wdt.c
new file mode 100644
index 000000000000..3f75129eb0a9
--- /dev/null
+++ b/drivers/watchdog/da9052_wdt.c
@@ -0,0 +1,251 @@
+/*
+ * System monitoring driver for DA9052 PMICs.
+ *
+ * Copyright(c) 2012 Dialog Semiconductor Ltd.
+ *
+ * Author: Anthony Olech <Anthony.Olech@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/delay.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <linux/time.h>
+#include <linux/watchdog.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+
+#include <linux/mfd/da9052/reg.h>
+#include <linux/mfd/da9052/da9052.h>
+
+#define DA9052_DEF_TIMEOUT      4
+#define DA9052_TWDMIN           256
+
+struct da9052_wdt_data {
+        struct watchdog_device wdt;
+        struct da9052 *da9052;
+        struct kref kref;
+        unsigned long jpast;
+};
+
+static const struct {
+        u8 reg_val;
+        int time;  /* Seconds */
+} da9052_wdt_maps[] = {
+        { 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 void da9052_wdt_release_resources(struct kref *r)
+{
+        struct da9052_wdt_data *driver_data =
+                container_of(r, struct da9052_wdt_data, kref);
+
+        kfree(driver_data);
+}
+
+static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev,
+                                  unsigned int timeout)
+{
+        struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+        struct da9052 *da9052 = driver_data->da9052;
+        int ret, i;
+
+        /*
+         * Disable the Watchdog timer before setting
+         * new time out.
+         */
+        ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+                                DA9052_CONTROLD_TWDSCALE, 0);
+        if (ret < 0) {
+                dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
+                        ret);
+                return ret;
+        }
+        if (timeout) {
+                /*
+                 * To change the timeout, da9052 needs to
+                 * be disabled for at least 150 us.
+                 */
+                udelay(150);
+
+                /* Set the desired timeout */
+                for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
+                        if (da9052_wdt_maps[i].time == timeout)
+                                break;
+
+                if (i == ARRAY_SIZE(da9052_wdt_maps))
+                        ret = -EINVAL;
+                else
+                        ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+                                                DA9052_CONTROLD_TWDSCALE,
+                                                da9052_wdt_maps[i].reg_val);
+                if (ret < 0) {
+                        dev_err(da9052->dev,
+                                "Failed to update timescale bit, %d\n", ret);
+                        return ret;
+                }
+
+                wdt_dev->timeout = timeout;
+                driver_data->jpast = jiffies;
+        }
+
+        return 0;
+}
+
+static void da9052_wdt_ref(struct watchdog_device *wdt_dev)
+{
+        struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+
+        kref_get(&driver_data->kref);
+}
+
+static void da9052_wdt_unref(struct watchdog_device *wdt_dev)
+{
+        struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+
+        kref_put(&driver_data->kref, da9052_wdt_release_resources);
+}
+
+static int da9052_wdt_start(struct watchdog_device *wdt_dev)
+{
+        return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
+}
+
+static int da9052_wdt_stop(struct watchdog_device *wdt_dev)
+{
+        return da9052_wdt_set_timeout(wdt_dev, 0);
+}
+
+static int da9052_wdt_ping(struct watchdog_device *wdt_dev)
+{
+        struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev);
+        struct da9052 *da9052 = driver_data->da9052;
+        unsigned long msec, jnow = jiffies;
+        int ret;
+
+        /*
+         * We have a minimum time for watchdog window called TWDMIN. A write
+         * to the watchdog before this elapsed time should cause an error.
+         */
+        msec = (jnow - driver_data->jpast) * 1000/HZ;
+        if (msec < DA9052_TWDMIN)
+                mdelay(msec);
+
+        /* Reset the watchdog timer */
+        ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+                                DA9052_CONTROLD_WATCHDOG, 1 << 7);
+        if (ret < 0)
+                goto err_strobe;
+
+        /*
+         * FIXME: Reset the watchdog core, in general PMIC
+         * is supposed to do this
+         */
+        ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+                                DA9052_CONTROLD_WATCHDOG, 0 << 7);
+err_strobe:
+        return ret;
+}
+
+static struct watchdog_info da9052_wdt_info = {
+        .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+        .identity       = "DA9052 Watchdog",
+};
+
+static const struct watchdog_ops da9052_wdt_ops = {
+        .owner = THIS_MODULE,
+        .start = da9052_wdt_start,
+        .stop = da9052_wdt_stop,
+        .ping = da9052_wdt_ping,
+        .set_timeout = da9052_wdt_set_timeout,
+        .ref = da9052_wdt_ref,
+        .unref = da9052_wdt_unref,
+};
+
+
+static int __devinit da9052_wdt_probe(struct platform_device *pdev)
+{
+        struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent);
+        struct da9052_wdt_data *driver_data;
+        struct watchdog_device *da9052_wdt;
+        int ret;
+
+        driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data),
+                                   GFP_KERNEL);
+        if (!driver_data) {
+                dev_err(da9052->dev, "Unable to alloacate watchdog device\n");
+                ret = -ENOMEM;
+                goto err;
+        }
+        driver_data->da9052 = da9052;
+
+        da9052_wdt = &driver_data->wdt;
+
+        da9052_wdt->timeout = DA9052_DEF_TIMEOUT;
+        da9052_wdt->info = &da9052_wdt_info;
+        da9052_wdt->ops = &da9052_wdt_ops;
+        watchdog_set_drvdata(da9052_wdt, driver_data);
+
+        kref_init(&driver_data->kref);
+
+        ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+                                DA9052_CONTROLD_TWDSCALE, 0);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
+                        ret);
+                goto err;
+        }
+
+        ret = watchdog_register_device(&driver_data->wdt);
+        if (ret != 0) {
+                dev_err(da9052->dev, "watchdog_register_device() failed: %d\n",
+                        ret);
+                goto err;
+        }
+
+        dev_set_drvdata(&pdev->dev, driver_data);
+err:
+        return ret;
+}
+
+static int __devexit da9052_wdt_remove(struct platform_device *pdev)
+{
+        struct da9052_wdt_data *driver_data = dev_get_drvdata(&pdev->dev);
+
+        watchdog_unregister_device(&driver_data->wdt);
+        kref_put(&driver_data->kref, da9052_wdt_release_resources);
+
+        return 0;
+}
+
+static struct platform_driver da9052_wdt_driver = {
+        .probe = da9052_wdt_probe,
+        .remove = __devexit_p(da9052_wdt_remove),
+        .driver = {
+                .name   = "da9052-watchdog",
+        },
+};
+
+module_platform_driver(da9052_wdt_driver);
+
+MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
+MODULE_DESCRIPTION("DA9052 SM Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9052-watchdog");