Quelle  wm831x_wdt.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0+
/*
 * Watchdog driver for the wm831x PMICs
 *
 * Copyright (C) 2009 Wolfson Microelectronics
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/watchdog.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) ")");

struct wm831x_wdt_drvdata {
 struct watchdog_device wdt;
 struct wm831x *wm831x;
 struct mutex lock;
 int update_state;
};

/* We can't use the sub-second values here but they're included
 * for completeness.  */
static struct {
 unsigned int time;  /* Seconds */
 u16 val;            /* WDOG_TO value */
} wm831x_wdt_cfgs[] = {
 {  1, 2 },
 {  2, 3 },
 {  4, 4 },
 {  8, 5 },
 { 16, 6 },
 { 32, 7 },
 { 33, 7 },  /* Actually 32.768s so include both, others round down */
};

static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
{
 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
 struct wm831x *wm831x = driver_data->wm831x;
 int ret;

 mutex_lock(&driver_data->lock);

 ret = wm831x_reg_unlock(wm831x);
 if (ret == 0) {
  ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
          WM831X_WDOG_ENA, WM831X_WDOG_ENA);
  wm831x_reg_lock(wm831x);
 } else {
  dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
   ret);
 }

 mutex_unlock(&driver_data->lock);

 return ret;
}

static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
{
 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
 struct wm831x *wm831x = driver_data->wm831x;
 int ret;

 mutex_lock(&driver_data->lock);

 ret = wm831x_reg_unlock(wm831x);
 if (ret == 0) {
  ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
          WM831X_WDOG_ENA, 0);
  wm831x_reg_lock(wm831x);
 } else {
  dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
   ret);
 }

 mutex_unlock(&driver_data->lock);

 return ret;
}

static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
{
 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
 struct wm831x *wm831x = driver_data->wm831x;
 int ret;
 u16 reg;

 mutex_lock(&driver_data->lock);

 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);

 if (!(reg & WM831X_WDOG_RST_SRC)) {
  dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
  ret = -EINVAL;
  goto out;
 }

 reg |= WM831X_WDOG_RESET;

 ret = wm831x_reg_unlock(wm831x);
 if (ret == 0) {
  ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
  wm831x_reg_lock(wm831x);
 } else {
  dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
   ret);
 }

out:
 mutex_unlock(&driver_data->lock);

 return ret;
}

static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
      unsigned int timeout)
{
 struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
 struct wm831x *wm831x = driver_data->wm831x;
 int ret, i;

 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
  if (wm831x_wdt_cfgs[i].time == timeout)
   break;
 if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
  return -EINVAL;

 ret = wm831x_reg_unlock(wm831x);
 if (ret == 0) {
  ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
          WM831X_WDOG_TO_MASK,
          wm831x_wdt_cfgs[i].val);
  wm831x_reg_lock(wm831x);
 } else {
  dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
   ret);
 }

 wdt_dev->timeout = timeout;

 return ret;
}

static const struct watchdog_info wm831x_wdt_info = {
 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 .identity = "WM831x Watchdog",
};

static const struct watchdog_ops wm831x_wdt_ops = {
 .owner = THIS_MODULE,
 .start = wm831x_wdt_start,
 .stop = wm831x_wdt_stop,
 .ping = wm831x_wdt_ping,
 .set_timeout = wm831x_wdt_set_timeout,
};

static int wm831x_wdt_probe(struct platform_device *pdev)
{
 struct device *dev = &pdev->dev;
 struct wm831x *wm831x = dev_get_drvdata(dev->parent);
 struct wm831x_pdata *chip_pdata = dev_get_platdata(dev->parent);
 struct wm831x_watchdog_pdata *pdata;
 struct wm831x_wdt_drvdata *driver_data;
 struct watchdog_device *wm831x_wdt;
 int reg, ret, i;

 ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
 if (ret < 0) {
  dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
   ret);
  return ret;
 }
 reg = ret;

 if (reg & WM831X_WDOG_DEBUG)
  dev_warn(wm831x->dev, "Watchdog is paused\n");

 driver_data = devm_kzalloc(dev, sizeof(*driver_data), GFP_KERNEL);
 if (!driver_data)
  return -ENOMEM;

 mutex_init(&driver_data->lock);
 driver_data->wm831x = wm831x;

 wm831x_wdt = &driver_data->wdt;

 wm831x_wdt->info = &wm831x_wdt_info;
 wm831x_wdt->ops = &wm831x_wdt_ops;
 wm831x_wdt->parent = dev;
 watchdog_set_nowayout(wm831x_wdt, nowayout);
 watchdog_set_drvdata(wm831x_wdt, driver_data);

 reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
 reg &= WM831X_WDOG_TO_MASK;
 for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
  if (wm831x_wdt_cfgs[i].val == reg)
   break;
 if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
  dev_warn(wm831x->dev,
    "Unknown watchdog timeout: %x\n", reg);
 else
  wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;

 /* Apply any configuration */
 if (chip_pdata)
  pdata = chip_pdata->watchdog;
 else
  pdata = NULL;

 if (pdata) {
  reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
    WM831X_WDOG_RST_SRC);

  reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
  reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
  reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;

  ret = wm831x_reg_unlock(wm831x);
  if (ret == 0) {
   ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
   wm831x_reg_lock(wm831x);
  } else {
   dev_err(wm831x->dev,
    "Failed to unlock security key: %d\n", ret);
   return ret;
  }
 }

 return devm_watchdog_register_device(dev, &driver_data->wdt);
}

static struct platform_driver wm831x_wdt_driver = {
 .probe = wm831x_wdt_probe,
 .driver = {
  .name = "wm831x-watchdog",
 },
};

module_platform_driver(wm831x_wdt_driver);

MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM831x Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-watchdog");