| 1 | /* |
| 2 | * Watchdog driver for the wm8350 |
| 3 | * |
| 4 | * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation |
| 9 | */ |
| 10 | |
| 11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/moduleparam.h> |
| 15 | #include <linux/types.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/platform_device.h> |
| 18 | #include <linux/watchdog.h> |
| 19 | #include <linux/uaccess.h> |
| 20 | #include <linux/mfd/wm8350/core.h> |
| 21 | |
| 22 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 23 | module_param(nowayout, bool, 0); |
| 24 | MODULE_PARM_DESC(nowayout, |
| 25 | "Watchdog cannot be stopped once started (default=" |
| 26 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 27 | |
| 28 | static DEFINE_MUTEX(wdt_mutex); |
| 29 | |
| 30 | static struct { |
| 31 | unsigned int time; /* Seconds */ |
| 32 | u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */ |
| 33 | } wm8350_wdt_cfgs[] = { |
| 34 | { 1, 0x02 }, |
| 35 | { 2, 0x04 }, |
| 36 | { 4, 0x05 }, |
| 37 | }; |
| 38 | |
| 39 | static int wm8350_wdt_set_timeout(struct watchdog_device *wdt_dev, |
| 40 | unsigned int timeout) |
| 41 | { |
| 42 | struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev); |
| 43 | int ret, i; |
| 44 | u16 reg; |
| 45 | |
| 46 | for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++) |
| 47 | if (wm8350_wdt_cfgs[i].time == timeout) |
| 48 | break; |
| 49 | if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) |
| 50 | return -EINVAL; |
| 51 | |
| 52 | mutex_lock(&wdt_mutex); |
| 53 | wm8350_reg_unlock(wm8350); |
| 54 | |
| 55 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); |
| 56 | reg &= ~WM8350_WDOG_TO_MASK; |
| 57 | reg |= wm8350_wdt_cfgs[i].val; |
| 58 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); |
| 59 | |
| 60 | wm8350_reg_lock(wm8350); |
| 61 | mutex_unlock(&wdt_mutex); |
| 62 | |
| 63 | wdt_dev->timeout = timeout; |
| 64 | return ret; |
| 65 | } |
| 66 | |
| 67 | static int wm8350_wdt_start(struct watchdog_device *wdt_dev) |
| 68 | { |
| 69 | struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev); |
| 70 | int ret; |
| 71 | u16 reg; |
| 72 | |
| 73 | mutex_lock(&wdt_mutex); |
| 74 | wm8350_reg_unlock(wm8350); |
| 75 | |
| 76 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); |
| 77 | reg &= ~WM8350_WDOG_MODE_MASK; |
| 78 | reg |= 0x20; |
| 79 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); |
| 80 | |
| 81 | wm8350_reg_lock(wm8350); |
| 82 | mutex_unlock(&wdt_mutex); |
| 83 | |
| 84 | return ret; |
| 85 | } |
| 86 | |
| 87 | static int wm8350_wdt_stop(struct watchdog_device *wdt_dev) |
| 88 | { |
| 89 | struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev); |
| 90 | int ret; |
| 91 | u16 reg; |
| 92 | |
| 93 | mutex_lock(&wdt_mutex); |
| 94 | wm8350_reg_unlock(wm8350); |
| 95 | |
| 96 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); |
| 97 | reg &= ~WM8350_WDOG_MODE_MASK; |
| 98 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); |
| 99 | |
| 100 | wm8350_reg_lock(wm8350); |
| 101 | mutex_unlock(&wdt_mutex); |
| 102 | |
| 103 | return ret; |
| 104 | } |
| 105 | |
| 106 | static int wm8350_wdt_ping(struct watchdog_device *wdt_dev) |
| 107 | { |
| 108 | struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev); |
| 109 | int ret; |
| 110 | u16 reg; |
| 111 | |
| 112 | mutex_lock(&wdt_mutex); |
| 113 | |
| 114 | reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); |
| 115 | ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); |
| 116 | |
| 117 | mutex_unlock(&wdt_mutex); |
| 118 | |
| 119 | return ret; |
| 120 | } |
| 121 | |
| 122 | static const struct watchdog_info wm8350_wdt_info = { |
| 123 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
| 124 | .identity = "WM8350 Watchdog", |
| 125 | }; |
| 126 | |
| 127 | static const struct watchdog_ops wm8350_wdt_ops = { |
| 128 | .owner = THIS_MODULE, |
| 129 | .start = wm8350_wdt_start, |
| 130 | .stop = wm8350_wdt_stop, |
| 131 | .ping = wm8350_wdt_ping, |
| 132 | .set_timeout = wm8350_wdt_set_timeout, |
| 133 | }; |
| 134 | |
| 135 | static struct watchdog_device wm8350_wdt = { |
| 136 | .info = &wm8350_wdt_info, |
| 137 | .ops = &wm8350_wdt_ops, |
| 138 | .timeout = 4, |
| 139 | .min_timeout = 1, |
| 140 | .max_timeout = 4, |
| 141 | }; |
| 142 | |
| 143 | static int wm8350_wdt_probe(struct platform_device *pdev) |
| 144 | { |
| 145 | struct wm8350 *wm8350 = platform_get_drvdata(pdev); |
| 146 | |
| 147 | if (!wm8350) { |
| 148 | pr_err("No driver data supplied\n"); |
| 149 | return -ENODEV; |
| 150 | } |
| 151 | |
| 152 | watchdog_set_nowayout(&wm8350_wdt, nowayout); |
| 153 | watchdog_set_drvdata(&wm8350_wdt, wm8350); |
| 154 | wm8350_wdt.parent = &pdev->dev; |
| 155 | |
| 156 | /* Default to 4s timeout */ |
| 157 | wm8350_wdt_set_timeout(&wm8350_wdt, 4); |
| 158 | |
| 159 | return watchdog_register_device(&wm8350_wdt); |
| 160 | } |
| 161 | |
| 162 | static int wm8350_wdt_remove(struct platform_device *pdev) |
| 163 | { |
| 164 | watchdog_unregister_device(&wm8350_wdt); |
| 165 | return 0; |
| 166 | } |
| 167 | |
| 168 | static struct platform_driver wm8350_wdt_driver = { |
| 169 | .probe = wm8350_wdt_probe, |
| 170 | .remove = wm8350_wdt_remove, |
| 171 | .driver = { |
| 172 | .name = "wm8350-wdt", |
| 173 | }, |
| 174 | }; |
| 175 | |
| 176 | module_platform_driver(wm8350_wdt_driver); |
| 177 | |
| 178 | MODULE_AUTHOR("Mark Brown"); |
| 179 | MODULE_DESCRIPTION("WM8350 Watchdog"); |
| 180 | MODULE_LICENSE("GPL"); |
| 181 | MODULE_ALIAS("platform:wm8350-wdt"); |