![Guenter Roeck](/assets/img/avatar_default.png)
Use device managed functions to simplify error handling, reduce source code size, improve readability, and reduce the likelyhood of bugs. Other improvements as listed below. The conversion was done automatically with coccinelle using the following semantic patches. The semantic patches and the scripts used to generate this commit log are available at https://github.com/groeck/coccinelle-patches - Drop assignments to otherwise unused variables - Drop empty remove function - Introduce local variable 'struct device *dev' and use it instead of dereferencing it repeatedly - Use devm_watchdog_register_driver() to register watchdog device Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
206 lines
5 KiB
C
206 lines
5 KiB
C
/*
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* Watchdog driver for TS-4800 based boards
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*
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* Copyright (c) 2015 - Savoir-faire Linux
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/kernel.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/regmap.h>
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#include <linux/watchdog.h>
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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/* possible feed values */
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#define TS4800_WDT_FEED_2S 0x1
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#define TS4800_WDT_FEED_10S 0x2
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#define TS4800_WDT_DISABLE 0x3
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struct ts4800_wdt {
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struct watchdog_device wdd;
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struct regmap *regmap;
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u32 feed_offset;
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u32 feed_val;
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};
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/*
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* TS-4800 supports the following timeout values:
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*
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* value desc
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* ---------------------
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* 0 feed for 338ms
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* 1 feed for 2.706s
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* 2 feed for 10.824s
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* 3 disable watchdog
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*
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* Keep the regmap/timeout map ordered by timeout
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*/
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static const struct {
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const int timeout;
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const int regval;
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} ts4800_wdt_map[] = {
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{ 2, TS4800_WDT_FEED_2S },
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{ 10, TS4800_WDT_FEED_10S },
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};
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#define MAX_TIMEOUT_INDEX (ARRAY_SIZE(ts4800_wdt_map) - 1)
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static void ts4800_write_feed(struct ts4800_wdt *wdt, u32 val)
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{
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regmap_write(wdt->regmap, wdt->feed_offset, val);
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}
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static int ts4800_wdt_start(struct watchdog_device *wdd)
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{
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struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
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ts4800_write_feed(wdt, wdt->feed_val);
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return 0;
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}
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static int ts4800_wdt_stop(struct watchdog_device *wdd)
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{
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struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
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ts4800_write_feed(wdt, TS4800_WDT_DISABLE);
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return 0;
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}
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static int ts4800_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
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int i;
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for (i = 0; i < MAX_TIMEOUT_INDEX; i++) {
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if (ts4800_wdt_map[i].timeout >= timeout)
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break;
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}
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wdd->timeout = ts4800_wdt_map[i].timeout;
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wdt->feed_val = ts4800_wdt_map[i].regval;
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return 0;
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}
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static const struct watchdog_ops ts4800_wdt_ops = {
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.owner = THIS_MODULE,
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.start = ts4800_wdt_start,
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.stop = ts4800_wdt_stop,
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.set_timeout = ts4800_wdt_set_timeout,
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};
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static const struct watchdog_info ts4800_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
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.identity = "TS-4800 Watchdog",
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};
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static int ts4800_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct device_node *syscon_np;
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struct watchdog_device *wdd;
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struct ts4800_wdt *wdt;
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u32 reg;
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int ret;
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syscon_np = of_parse_phandle(np, "syscon", 0);
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if (!syscon_np) {
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dev_err(dev, "no syscon property\n");
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return -ENODEV;
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}
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ret = of_property_read_u32_index(np, "syscon", 1, ®);
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if (ret < 0) {
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dev_err(dev, "no offset in syscon\n");
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return ret;
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}
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/* allocate memory for watchdog struct */
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wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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/* set regmap and offset to know where to write */
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wdt->feed_offset = reg;
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wdt->regmap = syscon_node_to_regmap(syscon_np);
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of_node_put(syscon_np);
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if (IS_ERR(wdt->regmap)) {
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dev_err(dev, "cannot get parent's regmap\n");
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return PTR_ERR(wdt->regmap);
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}
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/* Initialize struct watchdog_device */
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wdd = &wdt->wdd;
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wdd->parent = dev;
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wdd->info = &ts4800_wdt_info;
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wdd->ops = &ts4800_wdt_ops;
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wdd->min_timeout = ts4800_wdt_map[0].timeout;
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wdd->max_timeout = ts4800_wdt_map[MAX_TIMEOUT_INDEX].timeout;
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watchdog_set_drvdata(wdd, wdt);
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watchdog_set_nowayout(wdd, nowayout);
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watchdog_init_timeout(wdd, 0, dev);
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/*
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* As this watchdog supports only a few values, ts4800_wdt_set_timeout
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* must be called to initialize timeout and feed_val with valid values.
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* Default to maximum timeout if none, or an invalid one, is provided in
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* device tree.
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*/
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if (!wdd->timeout)
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wdd->timeout = wdd->max_timeout;
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ts4800_wdt_set_timeout(wdd, wdd->timeout);
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/*
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* The feed register is write-only, so it is not possible to determine
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* watchdog's state. Disable it to be in a known state.
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*/
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ts4800_wdt_stop(wdd);
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ret = devm_watchdog_register_device(dev, wdd);
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if (ret) {
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dev_err(dev, "failed to register watchdog device\n");
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return ret;
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}
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platform_set_drvdata(pdev, wdt);
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dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n",
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wdd->timeout, nowayout);
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return 0;
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}
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static const struct of_device_id ts4800_wdt_of_match[] = {
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{ .compatible = "technologic,ts4800-wdt", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, ts4800_wdt_of_match);
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static struct platform_driver ts4800_wdt_driver = {
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.probe = ts4800_wdt_probe,
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.driver = {
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.name = "ts4800_wdt",
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.of_match_table = ts4800_wdt_of_match,
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},
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};
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module_platform_driver(ts4800_wdt_driver);
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MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:ts4800_wdt");
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