// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 ROHM Semiconductors
// ROHM BD70528MWV watchdog driver
#include <linux/bcd.h>
#include <linux/kernel.h>
#include <linux/mfd/rohm-bd70528.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>
/*
* Max time we can set is 1 hour, 59 minutes and 59 seconds
* and Minimum time is 1 second
*/
#define WDT_MAX_MS ((2 * 60 * 60 - 1) * 1000)
#define WDT_MIN_MS 1000
#define DEFAULT_TIMEOUT 60
#define WD_CTRL_MAGIC1 0x55
#define WD_CTRL_MAGIC2 0xAA
struct wdtbd70528 {
struct device *dev;
struct regmap *regmap;
struct rohm_regmap_dev *mfd;
struct watchdog_device wdt;
};
/**
* bd70528_wdt_set - arm or disarm watchdog timer
*
* @data: device data for the PMIC instance we want to operate on
* @enable: new state of WDT. zero to disable, non zero to enable
* @old_state: previous state of WDT will be filled here
*
* Arm or disarm WDT on BD70528 PMIC. Expected to be called only by
* BD70528 RTC and BD70528 WDT drivers. The rtc_timer_lock must be taken
* by calling bd70528_wdt_lock before calling bd70528_wdt_set.
*/
int bd70528_wdt_set(struct rohm_regmap_dev *data, int enable, int *old_state)
{
int ret, i;
unsigned int tmp;
struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
chip);
u8 wd_ctrl_arr[3] = { WD_CTRL_MAGIC1, WD_CTRL_MAGIC2, 0 };
u8 *wd_ctrl = &wd_ctrl_arr[2];
ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
if (ret)
return ret;
*wd_ctrl = (u8)tmp;
if (old_state) {
if (*wd_ctrl & BD70528_MASK_WDT_EN)
*old_state |= BD70528_WDT_STATE_BIT;
else
*old_state &= ~BD70528_WDT_STATE_BIT;
if ((!enable) == (!(*old_state & BD70528_WDT_STATE_BIT)))
return 0;
}
if (enable) {
if (*wd_ctrl & BD70528_MASK_WDT_EN)
return 0;
*wd_ctrl |= BD70528_MASK_WDT_EN;
} else {
if (*wd_ctrl & BD70528_MASK_WDT_EN)
*wd_ctrl &= ~BD70528_MASK_WDT_EN;
else
return 0;
}
for (i = 0; i < 3; i++) {
ret = regmap_write(bd70528->chip.regmap, BD70528_REG_WDT_CTRL,
wd_ctrl_arr[i]);
if (ret)
return ret;
}
ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
if ((tmp & BD70528_MASK_WDT_EN) != (*wd_ctrl & BD70528_MASK_WDT_EN)) {
dev_err(bd70528->chip.dev,
"Watchdog ctrl mismatch (hw) 0x%x (set) 0x%x\n",
tmp, *wd_ctrl);
ret = -EIO;
}
return ret;
}
EXPORT_SYMBOL(bd70528_wdt_set);
/**
* bd70528_wdt_lock - take WDT lock
*
* @data: device data for the PMIC instance we want to operate on
*
* Lock WDT for arming/disarming in order to avoid race condition caused
* by WDT state changes initiated by WDT and RTC drivers.
*/
void bd70528_wdt_lock(struct rohm_regmap_dev *data)
{
struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
chip);
mutex_lock(&bd70528->rtc_timer_lock);
}
EXPORT_SYMBOL(bd70528_wdt_lock);
/**
* bd70528_wdt_unlock - unlock WDT lock
*
* @data: device data for the PMIC instance we want to operate on
*
* Unlock WDT lock which has previously been taken by call to
* bd70528_wdt_lock.
*/
void bd70528_wdt_unlock(struct rohm_regmap_dev *data)
{
struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
chip);
mutex_unlock(&bd70528->rtc_timer_lock);
}
EXPORT_SYMBOL(bd70528_wdt_unlock);
static int bd70528_wdt_set_locked(struct wdtbd70528 *w, int enable)
{
return bd70528_wdt_set(w->mfd, enable, NULL);
}
static int bd70528_wdt_change(struct wdtbd70528 *w, int enable)
{
int ret;
bd70528_wdt_lock(w->mfd);
ret = bd70528_wdt_set_locked(w, enable);
bd70528_wdt_unlock(w->mfd);
return ret;
}
static int bd70528_wdt_start(struct watchdog_device *wdt)
{
struct wdtbd70528 *w = watchdog_get_drvdata(wdt);
dev_dbg(w->dev, "WDT ping...\n");
return bd70528_wdt_change(w, 1);
}
static int bd70528_wdt_stop(struct watchdog_device *wdt)
{
struct wdtbd70528 *w = watchdog_get_drvdata(wdt);
dev_dbg(w->dev, "WDT stopping...\n");
return bd70528_wdt_change(w, 0);
}
static int bd70528_wdt_set_timeout(struct watchdog_device *wdt,
unsigned int timeout)
{
unsigned int hours;
unsigned int minutes;
unsigned int seconds;
int ret;
struct wdtbd70528 *w = watchdog_get_drvdata(wdt);
seconds = timeout;
hours = timeout / (60 * 60);
/* Maximum timeout is 1h 59m 59s => hours is 1 or 0 */
if (hours)
seconds -= (60 * 60);
minutes = seconds / 60;
seconds = seconds % 60;
bd70528_wdt_lock(w->mfd);
ret = bd70528_wdt_set_locked(w, 0);
if (ret)
goto out_unlock;
ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_HOUR,
BD70528_MASK_WDT_HOUR, hours);
if (ret) {
dev_err(w->dev, "Failed to set WDT hours\n");
goto out_en_unlock;
}
ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_MINUTE,
BD70528_MASK_WDT_MINUTE, bin2bcd(minutes));
if (ret) {
dev_err(w->dev, "Failed to set WDT minutes\n");
goto out_en_unlock;
}
ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_SEC,
BD70528_MASK_WDT_SEC, bin2bcd(seconds));
if (ret)
dev_err(w->dev, "Failed to set WDT seconds\n");
else
dev_dbg(w->dev, "WDT tmo set to %u\n", timeout);
out_en_unlock:
ret = bd70528_wdt_set_locked(w, 1);
out_unlock:
bd70528_wdt_unlock(w->mfd);
return ret;
}
static const struct watchdog_info bd70528_wdt_info = {
.identity = "bd70528-wdt",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops bd70528_wdt_ops = {
.start = bd70528_wdt_start,
.stop = bd70528_wdt_stop,
.set_timeout = bd70528_wdt_set_timeout,
};
static int bd70528_wdt_probe(struct platform_device *pdev)
{
struct rohm_regmap_dev *bd70528;
struct wdtbd70528 *w;
int ret;
unsigned int reg;
bd70528 = dev_get_drvdata(pdev->dev.parent);
if (!bd70528) {
dev_err(&pdev->dev, "No MFD driver data\n");
return -EINVAL;
}
w = devm_kzalloc(&pdev->dev, sizeof(*w), GFP_KERNEL);
if (!w)
return -ENOMEM;
w->regmap = bd70528->regmap;
w->mfd = bd70528;
w->dev = &pdev->dev;
w->wdt.info = &bd70528_wdt_info;
w->wdt.ops = &bd70528_wdt_ops;
w->wdt.min_hw_heartbeat_ms = WDT_MIN_MS;
w->wdt.max_hw_heartbeat_ms = WDT_MAX_MS;
w->wdt.parent = pdev->dev.parent;
w->wdt.timeout = DEFAULT_TIMEOUT;
watchdog_set_drvdata(&w->wdt, w);
watchdog_init_timeout(&w->wdt, 0, pdev->dev.parent);
ret = bd70528_wdt_set_timeout(&w->wdt, w->wdt.timeout);
if (ret) {
dev_err(&pdev->dev, "Failed to set the watchdog timeout\n");
return ret;
}
bd70528_wdt_lock(w->mfd);
ret = regmap_read(w->regmap, BD70528_REG_WDT_CTRL, ®);
bd70528_wdt_unlock(w->mfd);
if (ret) {
dev_err(&pdev->dev, "Failed to get the watchdog state\n");
return ret;
}
if (reg & BD70528_MASK_WDT_EN) {
dev_dbg(&pdev->dev, "watchdog was running during probe\n");
set_bit(WDOG_HW_RUNNING, &w->wdt.status);
}
ret = devm_watchdog_register_device(&pdev->dev, &w->wdt);
if (ret < 0)
dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);
return ret;
}
static struct platform_driver bd70528_wdt = {
.driver = {
.name = "bd70528-wdt"
},
.probe = bd70528_wdt_probe,
};
module_platform_driver(bd70528_wdt);
MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
MODULE_DESCRIPTION("BD70528 watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:bd70528-wdt");
