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Release 4.7 drivers/watchdog/da9062_wdt.c

Directory: drivers/watchdog
/*
 * 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; }

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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); } }

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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; }

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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; }

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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); }

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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; }

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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; }

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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; }

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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; }

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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; }

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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; }

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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");

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Directory: drivers/watchdog
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