--- /dev/null
+/*
+ * Watchdog driver for TS-4800 based boards
+ *
+ * Copyright (c) 2015 - Savoir-faire Linux
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.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) ")");
+
+/* possible feed values */
+#define TS4800_WDT_FEED_2S 0x1
+#define TS4800_WDT_FEED_10S 0x2
+#define TS4800_WDT_DISABLE 0x3
+
+struct ts4800_wdt {
+ struct watchdog_device wdd;
+ struct regmap *regmap;
+ u32 feed_offset;
+ u32 feed_val;
+};
+
+/*
+ * TS-4800 supports the following timeout values:
+ *
+ * value desc
+ * ---------------------
+ * 0 feed for 338ms
+ * 1 feed for 2.706s
+ * 2 feed for 10.824s
+ * 3 disable watchdog
+ *
+ * Keep the regmap/timeout map ordered by timeout
+ */
+static const struct {
+ const int timeout;
+ const int regval;
+} ts4800_wdt_map[] = {
+ { 2, TS4800_WDT_FEED_2S },
+ { 10, TS4800_WDT_FEED_10S },
+};
+
+#define MAX_TIMEOUT_INDEX (ARRAY_SIZE(ts4800_wdt_map) - 1)
+
+static void ts4800_write_feed(struct ts4800_wdt *wdt, u32 val)
+{
+ regmap_write(wdt->regmap, wdt->feed_offset, val);
+}
+
+static int ts4800_wdt_start(struct watchdog_device *wdd)
+{
+ struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ ts4800_write_feed(wdt, wdt->feed_val);
+ return 0;
+}
+
+static int ts4800_wdt_stop(struct watchdog_device *wdd)
+{
+ struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ ts4800_write_feed(wdt, TS4800_WDT_DISABLE);
+ return 0;
+}
+
+static int ts4800_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
+ int i;
+
+ for (i = 0; i < MAX_TIMEOUT_INDEX; i++) {
+ if (ts4800_wdt_map[i].timeout >= timeout)
+ break;
+ }
+
+ wdd->timeout = ts4800_wdt_map[i].timeout;
+ wdt->feed_val = ts4800_wdt_map[i].regval;
+
+ return 0;
+}
+
+static const struct watchdog_ops ts4800_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = ts4800_wdt_start,
+ .stop = ts4800_wdt_stop,
+ .set_timeout = ts4800_wdt_set_timeout,
+};
+
+static const struct watchdog_info ts4800_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+ .identity = "TS-4800 Watchdog",
+};
+
+static int ts4800_wdt_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device_node *syscon_np;
+ struct watchdog_device *wdd;
+ struct ts4800_wdt *wdt;
+ u32 reg;
+ int ret;
+
+ syscon_np = of_parse_phandle(np, "syscon", 0);
+ if (!syscon_np) {
+ dev_err(&pdev->dev, "no syscon property\n");
+ return -ENODEV;
+ }
+
+ ret = of_property_read_u32_index(np, "syscon", 1, ®);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "no offset in syscon\n");
+ return ret;
+ }
+
+ /* allocate memory for watchdog struct */
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ /* set regmap and offset to know where to write */
+ wdt->feed_offset = reg;
+ wdt->regmap = syscon_node_to_regmap(syscon_np);
+ if (IS_ERR(wdt->regmap)) {
+ dev_err(&pdev->dev, "cannot get parent's regmap\n");
+ return PTR_ERR(wdt->regmap);
+ }
+
+ /* Initialize struct watchdog_device */
+ wdd = &wdt->wdd;
+ wdd->parent = &pdev->dev;
+ wdd->info = &ts4800_wdt_info;
+ wdd->ops = &ts4800_wdt_ops;
+ wdd->min_timeout = ts4800_wdt_map[0].timeout;
+ wdd->max_timeout = ts4800_wdt_map[MAX_TIMEOUT_INDEX].timeout;
+
+ watchdog_set_drvdata(wdd, wdt);
+ watchdog_set_nowayout(wdd, nowayout);
+ watchdog_init_timeout(wdd, 0, &pdev->dev);
+
+ /*
+ * As this watchdog supports only a few values, ts4800_wdt_set_timeout
+ * must be called to initialize timeout and feed_val with valid values.
+ * Default to maximum timeout if none, or an invalid one, is provided in
+ * device tree.
+ */
+ if (!wdd->timeout)
+ wdd->timeout = wdd->max_timeout;
+ ts4800_wdt_set_timeout(wdd, wdd->timeout);
+
+ /*
+ * The feed register is write-only, so it is not possible to determine
+ * watchdog's state. Disable it to be in a known state.
+ */
+ ts4800_wdt_stop(wdd);
+
+ ret = watchdog_register_device(wdd);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to register watchdog device\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+
+ dev_info(&pdev->dev,
+ "initialized (timeout = %d sec, nowayout = %d)\n",
+ wdd->timeout, nowayout);
+
+ return 0;
+}
+
+static int ts4800_wdt_remove(struct platform_device *pdev)
+{
+ struct ts4800_wdt *wdt = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&wdt->wdd);
+
+ return 0;
+}
+
+static const struct of_device_id ts4800_wdt_of_match[] = {
+ { .compatible = "technologic,ts4800-wdt", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ts4800_wdt_of_match);
+
+static struct platform_driver ts4800_wdt_driver = {
+ .probe = ts4800_wdt_probe,
+ .remove = ts4800_wdt_remove,
+ .driver = {
+ .name = "ts4800_wdt",
+ .of_match_table = ts4800_wdt_of_match,
+ },
+};
+
+module_platform_driver(ts4800_wdt_driver);
+
+MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:ts4800_wdt");
projects / karo-tx-linux.git / commitdiff