diff options
Diffstat (limited to 'drivers/watchdog/jz4740_wdt.c')
| -rw-r--r-- | drivers/watchdog/jz4740_wdt.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c new file mode 100644 index 000000000..395bde79e --- /dev/null +++ b/drivers/watchdog/jz4740_wdt.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net> + * JZ4740 Watchdog driver + */ + +#include <linux/mfd/ingenic-tcu.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/watchdog.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/device.h> +#include <linux/clk.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/regmap.h> + +#define DEFAULT_HEARTBEAT 5 +#define MAX_HEARTBEAT 2048 + +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) ")"); + +static unsigned int heartbeat = DEFAULT_HEARTBEAT; +module_param(heartbeat, uint, 0); +MODULE_PARM_DESC(heartbeat, + "Watchdog heartbeat period in seconds from 1 to " + __MODULE_STRING(MAX_HEARTBEAT) ", default " + __MODULE_STRING(DEFAULT_HEARTBEAT)); + +struct jz4740_wdt_drvdata { + struct watchdog_device wdt; + struct regmap *map; + struct clk *clk; + unsigned long clk_rate; +}; + +static int jz4740_wdt_ping(struct watchdog_device *wdt_dev) +{ + struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); + + regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0); + + return 0; +} + +static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int new_timeout) +{ + struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); + u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout); + unsigned int tcer; + + regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer); + regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0); + + regmap_write(drvdata->map, TCU_REG_WDT_TDR, timeout_value); + regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0); + + if (tcer & TCU_WDT_TCER_TCEN) + regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN); + + wdt_dev->timeout = new_timeout; + return 0; +} + +static int jz4740_wdt_start(struct watchdog_device *wdt_dev) +{ + struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); + unsigned int tcer; + int ret; + + ret = clk_prepare_enable(drvdata->clk); + if (ret) + return ret; + + regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer); + + jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout); + + /* Start watchdog if it wasn't started already */ + if (!(tcer & TCU_WDT_TCER_TCEN)) + regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN); + + return 0; +} + +static int jz4740_wdt_stop(struct watchdog_device *wdt_dev) +{ + struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); + + regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0); + clk_disable_unprepare(drvdata->clk); + + return 0; +} + +static int jz4740_wdt_restart(struct watchdog_device *wdt_dev, + unsigned long action, void *data) +{ + wdt_dev->timeout = 0; + jz4740_wdt_start(wdt_dev); + return 0; +} + +static const struct watchdog_info jz4740_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .identity = "jz4740 Watchdog", +}; + +static const struct watchdog_ops jz4740_wdt_ops = { + .owner = THIS_MODULE, + .start = jz4740_wdt_start, + .stop = jz4740_wdt_stop, + .ping = jz4740_wdt_ping, + .set_timeout = jz4740_wdt_set_timeout, + .restart = jz4740_wdt_restart, +}; + +#ifdef CONFIG_OF +static const struct of_device_id jz4740_wdt_of_matches[] = { + { .compatible = "ingenic,jz4740-watchdog", }, + { .compatible = "ingenic,jz4780-watchdog", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches); +#endif + +static int jz4740_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct jz4740_wdt_drvdata *drvdata; + struct watchdog_device *jz4740_wdt; + long rate; + int ret; + + drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata), + GFP_KERNEL); + if (!drvdata) + return -ENOMEM; + + drvdata->clk = devm_clk_get(&pdev->dev, "wdt"); + if (IS_ERR(drvdata->clk)) { + dev_err(&pdev->dev, "cannot find WDT clock\n"); + return PTR_ERR(drvdata->clk); + } + + /* Set smallest clock possible */ + rate = clk_round_rate(drvdata->clk, 1); + if (rate < 0) + return rate; + + ret = clk_set_rate(drvdata->clk, rate); + if (ret) + return ret; + + drvdata->clk_rate = rate; + jz4740_wdt = &drvdata->wdt; + jz4740_wdt->info = &jz4740_wdt_info; + jz4740_wdt->ops = &jz4740_wdt_ops; + jz4740_wdt->min_timeout = 1; + jz4740_wdt->max_timeout = 0xffff / rate; + jz4740_wdt->timeout = clamp(heartbeat, + jz4740_wdt->min_timeout, + jz4740_wdt->max_timeout); + jz4740_wdt->parent = dev; + watchdog_set_nowayout(jz4740_wdt, nowayout); + watchdog_set_drvdata(jz4740_wdt, drvdata); + + drvdata->map = device_node_to_regmap(dev->parent->of_node); + if (IS_ERR(drvdata->map)) { + dev_err(dev, "regmap not found\n"); + return PTR_ERR(drvdata->map); + } + + return devm_watchdog_register_device(dev, &drvdata->wdt); +} + +static struct platform_driver jz4740_wdt_driver = { + .probe = jz4740_wdt_probe, + .driver = { + .name = "jz4740-wdt", + .of_match_table = of_match_ptr(jz4740_wdt_of_matches), + }, +}; + +module_platform_driver(jz4740_wdt_driver); + +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>"); +MODULE_DESCRIPTION("jz4740 Watchdog Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:jz4740-wdt"); |