diff options
Diffstat (limited to 'drivers/watchdog/da9062_wdt.c')
| -rw-r--r-- | drivers/watchdog/da9062_wdt.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c new file mode 100644 index 000000000000..b3a870ce85be --- /dev/null +++ b/drivers/watchdog/da9062_wdt.c @@ -0,0 +1,253 @@ +/* + * da9062_wdt.c - WDT device driver for DA9062 + * Copyright (C) 2015 Dialog Semiconductor Ltd. + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/watchdog.h> +#include <linux/platform_device.h> +#include <linux/uaccess.h> +#include <linux/slab.h> +#include <linux/delay.h> +#include <linux/jiffies.h> +#include <linux/mfd/da9062/registers.h> +#include <linux/mfd/da9062/core.h> +#include <linux/regmap.h> +#include <linux/of.h> + +static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 }; +#define DA9062_TWDSCALE_DISABLE 0 +#define DA9062_TWDSCALE_MIN 1 +#define DA9062_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1) +#define DA9062_WDT_MIN_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MIN] +#define DA9062_WDT_MAX_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX] +#define DA9062_WDG_DEFAULT_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX-1] +#define DA9062_RESET_PROTECTION_MS 300 + +struct da9062_watchdog { + struct da9062 *hw; + struct watchdog_device wdtdev; + unsigned long j_time_stamp; +}; + +static void da9062_set_window_start(struct da9062_watchdog *wdt) +{ + wdt->j_time_stamp = jiffies; +} + +static void da9062_apply_window_protection(struct da9062_watchdog *wdt) +{ + unsigned long delay = msecs_to_jiffies(DA9062_RESET_PROTECTION_MS); + unsigned long timeout = wdt->j_time_stamp + delay; + unsigned long now = jiffies; + unsigned int diff_ms; + + /* if time-limit has not elapsed then wait for remainder */ + if (time_before(now, timeout)) { + diff_ms = jiffies_to_msecs(timeout-now); + dev_dbg(wdt->hw->dev, + "Kicked too quickly. Delaying %u msecs\n", diff_ms); + msleep(diff_ms); + } +} + +static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs) +{ + unsigned int i; + + for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) { + if (wdt_timeout[i] >= secs) + return i; + } + + return DA9062_TWDSCALE_MAX; +} + +static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt) +{ + int ret; + + da9062_apply_window_protection(wdt); + + ret = regmap_update_bits(wdt->hw->regmap, + DA9062AA_CONTROL_F, + DA9062AA_WATCHDOG_MASK, + DA9062AA_WATCHDOG_MASK); + + da9062_set_window_start(wdt); + + return ret; +} + +static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt, + unsigned int regval) +{ + struct da9062 *chip = wdt->hw; + int ret; + + ret = da9062_reset_watchdog_timer(wdt); + if (ret) + return ret; + + return regmap_update_bits(chip->regmap, + DA9062AA_CONTROL_D, + DA9062AA_TWDSCALE_MASK, + regval); +} + +static int da9062_wdt_start(struct watchdog_device *wdd) +{ + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); + unsigned int selector; + int ret; + + selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout); + ret = da9062_wdt_update_timeout_register(wdt, selector); + if (ret) + dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n", + ret); + + return ret; +} + +static int da9062_wdt_stop(struct watchdog_device *wdd) +{ + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); + int ret; + + ret = da9062_reset_watchdog_timer(wdt); + if (ret) { + dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n", + ret); + return ret; + } + + ret = regmap_update_bits(wdt->hw->regmap, + DA9062AA_CONTROL_D, + DA9062AA_TWDSCALE_MASK, + DA9062_TWDSCALE_DISABLE); + if (ret) + dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n", + ret); + + return ret; +} + +static int da9062_wdt_ping(struct watchdog_device *wdd) +{ + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); + int ret; + + ret = da9062_reset_watchdog_timer(wdt); + if (ret) + dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n", + ret); + + return ret; +} + +static int da9062_wdt_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd); + unsigned int selector; + int ret; + + selector = da9062_wdt_timeout_to_sel(timeout); + ret = da9062_wdt_update_timeout_register(wdt, selector); + if (ret) + dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n", + ret); + else + wdd->timeout = wdt_timeout[selector]; + + return ret; +} + +static const struct watchdog_info da9062_watchdog_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = "DA9062 WDT", +}; + +static const struct watchdog_ops da9062_watchdog_ops = { + .owner = THIS_MODULE, + .start = da9062_wdt_start, + .stop = da9062_wdt_stop, + .ping = da9062_wdt_ping, + .set_timeout = da9062_wdt_set_timeout, +}; + +static int da9062_wdt_probe(struct platform_device *pdev) +{ + int ret; + struct da9062 *chip; + struct da9062_watchdog *wdt; + + chip = dev_get_drvdata(pdev->dev.parent); + if (!chip) + return -EINVAL; + + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + wdt->hw = chip; + + wdt->wdtdev.info = &da9062_watchdog_info; + wdt->wdtdev.ops = &da9062_watchdog_ops; + wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT; + wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT; + wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT; + wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS; + + watchdog_set_drvdata(&wdt->wdtdev, wdt); + dev_set_drvdata(&pdev->dev, wdt); + + ret = watchdog_register_device(&wdt->wdtdev); + if (ret < 0) { + dev_err(wdt->hw->dev, + "watchdog registration failed (%d)\n", ret); + return ret; + } + + da9062_set_window_start(wdt); + + ret = da9062_wdt_ping(&wdt->wdtdev); + if (ret < 0) + watchdog_unregister_device(&wdt->wdtdev); + + return ret; +} + +static int da9062_wdt_remove(struct platform_device *pdev) +{ + struct da9062_watchdog *wdt = dev_get_drvdata(&pdev->dev); + + watchdog_unregister_device(&wdt->wdtdev); + return 0; +} + +static struct platform_driver da9062_wdt_driver = { + .probe = da9062_wdt_probe, + .remove = da9062_wdt_remove, + .driver = { + .name = "da9062-watchdog", + }, +}; +module_platform_driver(da9062_wdt_driver); + +MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>"); +MODULE_DESCRIPTION("WDT device driver for Dialog DA9062"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:da9062-watchdog"); |