diff options
Diffstat (limited to 'kernel/drivers/watchdog/rn5t618_wdt.c')
| -rw-r--r-- | kernel/drivers/watchdog/rn5t618_wdt.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/kernel/drivers/watchdog/rn5t618_wdt.c b/kernel/drivers/watchdog/rn5t618_wdt.c new file mode 100644 index 000000000..d1c12278c --- /dev/null +++ b/kernel/drivers/watchdog/rn5t618_wdt.c @@ -0,0 +1,198 @@ +/* + * Watchdog driver for Ricoh RN5T618 PMIC + * + * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/device.h> +#include <linux/mfd/rn5t618.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +#define DRIVER_NAME "rn5t618-wdt" + +static bool nowayout = WATCHDOG_NOWAYOUT; +static unsigned int timeout; + +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds"); + +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +struct rn5t618_wdt { + struct watchdog_device wdt_dev; + struct rn5t618 *rn5t618; +}; + +/* + * This array encodes the values of WDOGTIM field for the supported + * watchdog expiration times. If the watchdog is not accessed before + * the timer expiration, the PMU generates an interrupt and if the CPU + * doesn't clear it within one second the system is restarted. + */ +static const struct { + u8 reg_val; + unsigned int time; +} rn5t618_wdt_map[] = { + { 0, 1 }, + { 1, 8 }, + { 2, 32 }, + { 3, 128 }, +}; + +static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int t) +{ + struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); + int ret, i; + + for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) { + if (rn5t618_wdt_map[i].time + 1 >= t) + break; + } + + if (i == ARRAY_SIZE(rn5t618_wdt_map)) + return -EINVAL; + + ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, + RN5T618_WATCHDOG_WDOGTIM_M, + rn5t618_wdt_map[i].reg_val); + if (!ret) + wdt_dev->timeout = rn5t618_wdt_map[i].time; + + return ret; +} + +static int rn5t618_wdt_start(struct watchdog_device *wdt_dev) +{ + struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); + int ret; + + ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout); + if (ret) + return ret; + + /* enable repower-on */ + ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT, + RN5T618_REPCNT_REPWRON, + RN5T618_REPCNT_REPWRON); + if (ret) + return ret; + + /* enable watchdog */ + ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, + RN5T618_WATCHDOG_WDOGEN, + RN5T618_WATCHDOG_WDOGEN); + if (ret) + return ret; + + /* enable watchdog interrupt */ + return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN, + RN5T618_PWRIRQ_IR_WDOG, + RN5T618_PWRIRQ_IR_WDOG); +} + +static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev) +{ + struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); + + return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG, + RN5T618_WATCHDOG_WDOGEN, 0); +} + +static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev) +{ + struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev); + unsigned int val; + int ret; + + /* The counter is restarted after a R/W access to watchdog register */ + ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val); + if (ret) + return ret; + + ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val); + if (ret) + return ret; + + /* Clear pending watchdog interrupt */ + return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ, + RN5T618_PWRIRQ_IR_WDOG, 0); +} + +static struct watchdog_info rn5t618_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | + WDIOF_KEEPALIVEPING, + .identity = DRIVER_NAME, +}; + +static struct watchdog_ops rn5t618_wdt_ops = { + .owner = THIS_MODULE, + .start = rn5t618_wdt_start, + .stop = rn5t618_wdt_stop, + .ping = rn5t618_wdt_ping, + .set_timeout = rn5t618_wdt_set_timeout, +}; + +static int rn5t618_wdt_probe(struct platform_device *pdev) +{ + struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent); + struct rn5t618_wdt *wdt; + int min_timeout, max_timeout; + + wdt = devm_kzalloc(&pdev->dev, sizeof(struct rn5t618_wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + min_timeout = rn5t618_wdt_map[0].time; + max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time; + + wdt->rn5t618 = rn5t618; + wdt->wdt_dev.info = &rn5t618_wdt_info; + wdt->wdt_dev.ops = &rn5t618_wdt_ops; + wdt->wdt_dev.min_timeout = min_timeout; + wdt->wdt_dev.max_timeout = max_timeout; + wdt->wdt_dev.timeout = max_timeout; + wdt->wdt_dev.parent = &pdev->dev; + + watchdog_set_drvdata(&wdt->wdt_dev, wdt); + watchdog_init_timeout(&wdt->wdt_dev, timeout, &pdev->dev); + watchdog_set_nowayout(&wdt->wdt_dev, nowayout); + + platform_set_drvdata(pdev, wdt); + + return watchdog_register_device(&wdt->wdt_dev); +} + +static int rn5t618_wdt_remove(struct platform_device *pdev) +{ + struct rn5t618_wdt *wdt = platform_get_drvdata(pdev); + + watchdog_unregister_device(&wdt->wdt_dev); + + return 0; +} + +static struct platform_driver rn5t618_wdt_driver = { + .probe = rn5t618_wdt_probe, + .remove = rn5t618_wdt_remove, + .driver = { + .name = DRIVER_NAME, + }, +}; + +module_platform_driver(rn5t618_wdt_driver); + +MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>"); +MODULE_DESCRIPTION("RN5T618 watchdog driver"); +MODULE_LICENSE("GPL v2"); |