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/*
* Maxim MAX77620 Watchdog Driver
*
* Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
*
* Author: Laxman Dewangan <ldewangan@nvidia.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.
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/mfd/max77620.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/watchdog.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
struct max77620_wdt {
struct device *dev;
struct regmap *rmap;
struct watchdog_device wdt_dev;
};
static int max77620_wdt_start(struct watchdog_device *wdt_dev)
{
struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
MAX77620_WDTEN, MAX77620_WDTEN);
}
static int max77620_wdt_stop(struct watchdog_device *wdt_dev)
{
struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
MAX77620_WDTEN, 0);
}
static int max77620_wdt_ping(struct watchdog_device *wdt_dev)
{
struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
MAX77620_WDTC_MASK, 0x1);
}
static int max77620_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
unsigned int wdt_timeout;
u8 regval;
int ret;
switch (timeout) {
case 0 ... 2:
regval = MAX77620_TWD_2s;
wdt_timeout = 2;
break;
case 3 ... 16:
regval = MAX77620_TWD_16s;
wdt_timeout = 16;
break;
case 17 ... 64:
regval = MAX77620_TWD_64s;
wdt_timeout = 64;
break;
default:
regval = MAX77620_TWD_128s;
wdt_timeout = 128;
break;
}
ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
MAX77620_WDTC_MASK, 0x1);
if (ret < 0)
return ret;
ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
MAX77620_TWD_MASK, regval);
if (ret < 0)
return ret;
wdt_dev->timeout = wdt_timeout;
return 0;
}
static const struct watchdog_info max77620_wdt_info = {
.identity = "max77620-watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops max77620_wdt_ops = {
.start = max77620_wdt_start,
.stop = max77620_wdt_stop,
.ping = max77620_wdt_ping,
.set_timeout = max77620_wdt_set_timeout,
};
static int max77620_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct max77620_wdt *wdt;
struct watchdog_device *wdt_dev;
unsigned int regval;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->dev = dev;
wdt->rmap = dev_get_regmap(dev->parent, NULL);
if (!wdt->rmap) {
dev_err(wdt->dev, "Failed to get parent regmap\n");
return -ENODEV;
}
wdt_dev = &wdt->wdt_dev;
wdt_dev->info = &max77620_wdt_info;
wdt_dev->ops = &max77620_wdt_ops;
wdt_dev->min_timeout = 2;
wdt_dev->max_timeout = 128;
wdt_dev->max_hw_heartbeat_ms = 128 * 1000;
platform_set_drvdata(pdev, wdt);
/* Enable WD_RST_WK - WDT expire results in a restart */
ret = regmap_update_bits(wdt->rmap, MAX77620_REG_ONOFFCNFG2,
MAX77620_ONOFFCNFG2_WD_RST_WK,
MAX77620_ONOFFCNFG2_WD_RST_WK);
if (ret < 0) {
dev_err(wdt->dev, "Failed to set WD_RST_WK: %d\n", ret);
return ret;
}
/* Set WDT clear in OFF and sleep mode */
ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
MAX77620_WDTOFFC | MAX77620_WDTSLPC,
MAX77620_WDTOFFC | MAX77620_WDTSLPC);
if (ret < 0) {
dev_err(wdt->dev, "Failed to set WDT OFF mode: %d\n", ret);
return ret;
}
/* Check if WDT running and if yes then set flags properly */
ret = regmap_read(wdt->rmap, MAX77620_REG_CNFGGLBL2, ®val);
if (ret < 0) {
dev_err(wdt->dev, "Failed to read WDT CFG register: %d\n", ret);
return ret;
}
switch (regval & MAX77620_TWD_MASK) {
case MAX77620_TWD_2s:
wdt_dev->timeout = 2;
break;
case MAX77620_TWD_16s:
wdt_dev->timeout = 16;
break;
case MAX77620_TWD_64s:
wdt_dev->timeout = 64;
break;
default:
wdt_dev->timeout = 128;
break;
}
if (regval & MAX77620_WDTEN)
set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
watchdog_set_nowayout(wdt_dev, nowayout);
watchdog_set_drvdata(wdt_dev, wdt);
watchdog_stop_on_unregister(wdt_dev);
ret = devm_watchdog_register_device(dev, wdt_dev);
if (ret < 0) {
dev_err(dev, "watchdog registration failed: %d\n", ret);
return ret;
}
return 0;
}
static const struct platform_device_id max77620_wdt_devtype[] = {
{ .name = "max77620-watchdog", },
{ },
};
MODULE_DEVICE_TABLE(platform, max77620_wdt_devtype);
static struct platform_driver max77620_wdt_driver = {
.driver = {
.name = "max77620-watchdog",
},
.probe = max77620_wdt_probe,
.id_table = max77620_wdt_devtype,
};
module_platform_driver(max77620_wdt_driver);
MODULE_DESCRIPTION("Max77620 watchdog timer driver");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL v2");
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