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/*
* 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;
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");
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