linux/drivers/watchdog/da9063_wdt.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Watchdog driver for DA9063 PMICs.
   4 *
   5 * Copyright(c) 2012 Dialog Semiconductor Ltd.
   6 *
   7 * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
   8 *
   9 */
  10
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/watchdog.h>
  14#include <linux/platform_device.h>
  15#include <linux/uaccess.h>
  16#include <linux/slab.h>
  17#include <linux/delay.h>
  18#include <linux/mfd/da9063/registers.h>
  19#include <linux/mfd/da9063/core.h>
  20#include <linux/regmap.h>
  21
  22/*
  23 * Watchdog selector to timeout in seconds.
  24 *   0: WDT disabled;
  25 *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
  26 */
  27static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
  28#define DA9063_TWDSCALE_DISABLE         0
  29#define DA9063_TWDSCALE_MIN             1
  30#define DA9063_TWDSCALE_MAX             (ARRAY_SIZE(wdt_timeout) - 1)
  31#define DA9063_WDT_MIN_TIMEOUT          wdt_timeout[DA9063_TWDSCALE_MIN]
  32#define DA9063_WDT_MAX_TIMEOUT          wdt_timeout[DA9063_TWDSCALE_MAX]
  33#define DA9063_WDG_TIMEOUT              wdt_timeout[3]
  34#define DA9063_RESET_PROTECTION_MS      256
  35
  36static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
  37{
  38        unsigned int i;
  39
  40        for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
  41                if (wdt_timeout[i] >= secs)
  42                        return i;
  43        }
  44
  45        return DA9063_TWDSCALE_MAX;
  46}
  47
  48/*
  49 * Read the currently active timeout.
  50 * Zero means the watchdog is disabled.
  51 */
  52static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
  53{
  54        unsigned int val;
  55
  56        regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
  57
  58        return wdt_timeout[val & DA9063_TWDSCALE_MASK];
  59}
  60
  61static int da9063_wdt_disable_timer(struct da9063 *da9063)
  62{
  63        return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
  64                                  DA9063_TWDSCALE_MASK,
  65                                  DA9063_TWDSCALE_DISABLE);
  66}
  67
  68static int
  69da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
  70{
  71        unsigned int regval;
  72        int ret;
  73
  74        /*
  75         * The watchdog triggers a reboot if a timeout value is already
  76         * programmed because the timeout value combines two functions
  77         * in one: indicating the counter limit and starting the watchdog.
  78         * The watchdog must be disabled to be able to change the timeout
  79         * value if the watchdog is already running. Then we can set the
  80         * new timeout value which enables the watchdog again.
  81         */
  82        ret = da9063_wdt_disable_timer(da9063);
  83        if (ret)
  84                return ret;
  85
  86        usleep_range(150, 300);
  87        regval = da9063_wdt_timeout_to_sel(timeout);
  88
  89        return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
  90                                  DA9063_TWDSCALE_MASK, regval);
  91}
  92
  93static int da9063_wdt_start(struct watchdog_device *wdd)
  94{
  95        struct da9063 *da9063 = watchdog_get_drvdata(wdd);
  96        int ret;
  97
  98        ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
  99        if (ret)
 100                dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
 101                        ret);
 102
 103        return ret;
 104}
 105
 106static int da9063_wdt_stop(struct watchdog_device *wdd)
 107{
 108        struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 109        int ret;
 110
 111        ret = da9063_wdt_disable_timer(da9063);
 112        if (ret)
 113                dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
 114                          ret);
 115
 116        return ret;
 117}
 118
 119static int da9063_wdt_ping(struct watchdog_device *wdd)
 120{
 121        struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 122        int ret;
 123
 124        ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
 125                           DA9063_WATCHDOG);
 126        if (ret)
 127                dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
 128                          ret);
 129
 130        return ret;
 131}
 132
 133static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
 134                                  unsigned int timeout)
 135{
 136        struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 137        int ret = 0;
 138
 139        /*
 140         * There are two cases when a set_timeout() will be called:
 141         * 1. The watchdog is off and someone wants to set the timeout for the
 142         *    further use.
 143         * 2. The watchdog is already running and a new timeout value should be
 144         *    set.
 145         *
 146         * The watchdog can't store a timeout value not equal zero without
 147         * enabling the watchdog, so the timeout must be buffered by the driver.
 148         */
 149        if (watchdog_active(wdd))
 150                ret = da9063_wdt_update_timeout(da9063, timeout);
 151
 152        if (ret)
 153                dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
 154                        ret);
 155        else
 156                wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
 157
 158        return ret;
 159}
 160
 161static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 162                              void *data)
 163{
 164        struct da9063 *da9063 = watchdog_get_drvdata(wdd);
 165        int ret;
 166
 167        ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
 168                           DA9063_SHUTDOWN);
 169        if (ret)
 170                dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
 171                          ret);
 172
 173        return ret;
 174}
 175
 176static const struct watchdog_info da9063_watchdog_info = {
 177        .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 178        .identity = "DA9063 Watchdog",
 179};
 180
 181static const struct watchdog_ops da9063_watchdog_ops = {
 182        .owner = THIS_MODULE,
 183        .start = da9063_wdt_start,
 184        .stop = da9063_wdt_stop,
 185        .ping = da9063_wdt_ping,
 186        .set_timeout = da9063_wdt_set_timeout,
 187        .restart = da9063_wdt_restart,
 188};
 189
 190static int da9063_wdt_probe(struct platform_device *pdev)
 191{
 192        struct device *dev = &pdev->dev;
 193        struct da9063 *da9063;
 194        struct watchdog_device *wdd;
 195        unsigned int timeout;
 196
 197        if (!dev->parent)
 198                return -EINVAL;
 199
 200        da9063 = dev_get_drvdata(dev->parent);
 201        if (!da9063)
 202                return -EINVAL;
 203
 204        wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
 205        if (!wdd)
 206                return -ENOMEM;
 207
 208        wdd->info = &da9063_watchdog_info;
 209        wdd->ops = &da9063_watchdog_ops;
 210        wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
 211        wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
 212        wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
 213        wdd->parent = dev;
 214        wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 215
 216        watchdog_set_restart_priority(wdd, 128);
 217        watchdog_set_drvdata(wdd, da9063);
 218
 219        wdd->timeout = DA9063_WDG_TIMEOUT;
 220
 221        /* Use pre-configured timeout if watchdog is already running. */
 222        timeout = da9063_wdt_read_timeout(da9063);
 223        if (timeout)
 224                wdd->timeout = timeout;
 225
 226        /* Set timeout, maybe override it with DT value, scale it */
 227        watchdog_init_timeout(wdd, 0, dev);
 228        da9063_wdt_set_timeout(wdd, wdd->timeout);
 229
 230        /* Update timeout if the watchdog is already running. */
 231        if (timeout) {
 232                da9063_wdt_update_timeout(da9063, wdd->timeout);
 233                set_bit(WDOG_HW_RUNNING, &wdd->status);
 234        }
 235
 236        return devm_watchdog_register_device(dev, wdd);
 237}
 238
 239static struct platform_driver da9063_wdt_driver = {
 240        .probe = da9063_wdt_probe,
 241        .driver = {
 242                .name = DA9063_DRVNAME_WATCHDOG,
 243        },
 244};
 245module_platform_driver(da9063_wdt_driver);
 246
 247MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
 248MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
 249MODULE_LICENSE("GPL");
 250MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
 251