drivers/watchdog/wm8350_wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/wm8350_wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/wm8350_wdt.c
Extension
.c
Size
3968 bytes
Lines
172
Domain
Driver Families
Bucket
drivers/watchdog
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0+
/*
 * Watchdog driver for the wm8350
 *
 * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/mfd/wm8350/core.h>

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
		 "Watchdog cannot be stopped once started (default="
		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static DEFINE_MUTEX(wdt_mutex);

static struct {
	unsigned int time;  /* Seconds */
	u16 val;	    /* To be set in WM8350_SYSTEM_CONTROL_2 */
} wm8350_wdt_cfgs[] = {
	{ 1, 0x02 },
	{ 2, 0x04 },
	{ 4, 0x05 },
};

static int wm8350_wdt_set_timeout(struct watchdog_device *wdt_dev,
				  unsigned int timeout)
{
	struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
	int ret, i;
	u16 reg;

	for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
		if (wm8350_wdt_cfgs[i].time == timeout)
			break;
	if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
		return -EINVAL;

	mutex_lock(&wdt_mutex);
	wm8350_reg_unlock(wm8350);

	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
	reg &= ~WM8350_WDOG_TO_MASK;
	reg |= wm8350_wdt_cfgs[i].val;
	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

	wm8350_reg_lock(wm8350);
	mutex_unlock(&wdt_mutex);

	wdt_dev->timeout = timeout;
	return ret;
}

static int wm8350_wdt_start(struct watchdog_device *wdt_dev)
{
	struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
	int ret;
	u16 reg;

	mutex_lock(&wdt_mutex);
	wm8350_reg_unlock(wm8350);

	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
	reg &= ~WM8350_WDOG_MODE_MASK;
	reg |= 0x20;
	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

	wm8350_reg_lock(wm8350);
	mutex_unlock(&wdt_mutex);

	return ret;
}

static int wm8350_wdt_stop(struct watchdog_device *wdt_dev)
{
	struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
	int ret;
	u16 reg;

	mutex_lock(&wdt_mutex);

Annotation

Implementation Notes