--- /dev/null
+/*
+ * 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);
+ return ret;
+ }
+
+ wdt_dev->timeout = timeout;
+
+ return 0;
+}
+
+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;
+
+ /*
+ * 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 */
+ return da9055_reg_update(da9055, DA9055_REG_CONTROL_E,
+ DA9055_WATCHDOG_MASK, 1);
+}
+
+static void da9055_wdt_release_resources(struct kref *r)
+{
+}
+
+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)
+ 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;
+ }
+
+ platform_set_drvdata(pdev, 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 = platform_get_drvdata(pdev);
+
+ 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");
Code Review / kvmfornfv.git / blobdiff