| /* |
| * 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 = 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; |
| wdt->wdtdev.parent = &pdev->dev; |
| |
| 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"); |