339 lines
7.9 KiB
C
339 lines
7.9 KiB
C
/*
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* Watchdog driver for the wm831x PMICs
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*
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* Copyright (C) 2009 Wolfson Microelectronics
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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#include <linux/uaccess.h>
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#include <linux/gpio.h>
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#include <linux/mfd/wm831x/core.h>
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#include <linux/mfd/wm831x/pdata.h>
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#include <linux/mfd/wm831x/watchdog.h>
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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struct wm831x_wdt_drvdata {
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struct watchdog_device wdt;
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struct wm831x *wm831x;
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struct mutex lock;
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int update_gpio;
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int update_state;
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};
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/* We can't use the sub-second values here but they're included
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* for completeness. */
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static struct {
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unsigned int time; /* Seconds */
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u16 val; /* WDOG_TO value */
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} wm831x_wdt_cfgs[] = {
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{ 1, 2 },
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{ 2, 3 },
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{ 4, 4 },
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{ 8, 5 },
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{ 16, 6 },
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{ 32, 7 },
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{ 33, 7 }, /* Actually 32.768s so include both, others round down */
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};
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static int wm831x_wdt_start(struct watchdog_device *wdt_dev)
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{
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struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
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struct wm831x *wm831x = driver_data->wm831x;
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int ret;
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mutex_lock(&driver_data->lock);
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
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WM831X_WDOG_ENA, WM831X_WDOG_ENA);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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mutex_unlock(&driver_data->lock);
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return ret;
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}
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static int wm831x_wdt_stop(struct watchdog_device *wdt_dev)
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{
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struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
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struct wm831x *wm831x = driver_data->wm831x;
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int ret;
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mutex_lock(&driver_data->lock);
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
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WM831X_WDOG_ENA, 0);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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mutex_unlock(&driver_data->lock);
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return ret;
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}
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static int wm831x_wdt_ping(struct watchdog_device *wdt_dev)
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{
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struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
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struct wm831x *wm831x = driver_data->wm831x;
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int ret;
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u16 reg;
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mutex_lock(&driver_data->lock);
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if (driver_data->update_gpio) {
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gpio_set_value_cansleep(driver_data->update_gpio,
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driver_data->update_state);
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driver_data->update_state = !driver_data->update_state;
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ret = 0;
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goto out;
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}
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reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
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if (!(reg & WM831X_WDOG_RST_SRC)) {
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dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
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ret = -EINVAL;
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goto out;
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}
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reg |= WM831X_WDOG_RESET;
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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out:
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mutex_unlock(&driver_data->lock);
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return ret;
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}
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static int wm831x_wdt_set_timeout(struct watchdog_device *wdt_dev,
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unsigned int timeout)
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{
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struct wm831x_wdt_drvdata *driver_data = watchdog_get_drvdata(wdt_dev);
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struct wm831x *wm831x = driver_data->wm831x;
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int ret, i;
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for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
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if (wm831x_wdt_cfgs[i].time == timeout)
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break;
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if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
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ret = -EINVAL;
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
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WM831X_WDOG_TO_MASK,
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wm831x_wdt_cfgs[i].val);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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return ret;
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}
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static const struct watchdog_info wm831x_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.identity = "WM831x Watchdog",
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};
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static const struct watchdog_ops wm831x_wdt_ops = {
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.owner = THIS_MODULE,
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.start = wm831x_wdt_start,
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.stop = wm831x_wdt_stop,
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.ping = wm831x_wdt_ping,
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.set_timeout = wm831x_wdt_set_timeout,
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};
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static int __devinit wm831x_wdt_probe(struct platform_device *pdev)
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{
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struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
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struct wm831x_pdata *chip_pdata;
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struct wm831x_watchdog_pdata *pdata;
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struct wm831x_wdt_drvdata *driver_data;
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struct watchdog_device *wm831x_wdt;
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int reg, ret, i;
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ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
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if (ret < 0) {
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dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
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ret);
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goto err;
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}
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reg = ret;
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if (reg & WM831X_WDOG_DEBUG)
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dev_warn(wm831x->dev, "Watchdog is paused\n");
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driver_data = kzalloc(sizeof(*driver_data), GFP_KERNEL);
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if (!driver_data) {
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dev_err(wm831x->dev, "Unable to alloacate watchdog device\n");
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ret = -ENOMEM;
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goto err;
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}
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mutex_init(&driver_data->lock);
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driver_data->wm831x = wm831x;
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wm831x_wdt = &driver_data->wdt;
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wm831x_wdt->info = &wm831x_wdt_info;
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wm831x_wdt->ops = &wm831x_wdt_ops;
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watchdog_set_drvdata(wm831x_wdt, driver_data);
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if (nowayout)
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wm831x_wdt->status |= WDOG_NO_WAY_OUT;
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reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
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reg &= WM831X_WDOG_TO_MASK;
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for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
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if (wm831x_wdt_cfgs[i].val == reg)
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break;
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if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
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dev_warn(wm831x->dev,
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"Unknown watchdog timeout: %x\n", reg);
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else
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wm831x_wdt->timeout = wm831x_wdt_cfgs[i].time;
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/* Apply any configuration */
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if (pdev->dev.parent->platform_data) {
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chip_pdata = pdev->dev.parent->platform_data;
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pdata = chip_pdata->watchdog;
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} else {
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pdata = NULL;
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}
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if (pdata) {
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reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
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WM831X_WDOG_RST_SRC);
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reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
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reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
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reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
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if (pdata->update_gpio) {
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ret = gpio_request(pdata->update_gpio,
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"Watchdog update");
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if (ret < 0) {
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dev_err(wm831x->dev,
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"Failed to request update GPIO: %d\n",
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ret);
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goto err_alloc;
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}
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ret = gpio_direction_output(pdata->update_gpio, 0);
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if (ret != 0) {
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dev_err(wm831x->dev,
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"gpio_direction_output returned: %d\n",
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ret);
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goto err_gpio;
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}
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driver_data->update_gpio = pdata->update_gpio;
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/* Make sure the watchdog takes hardware updates */
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reg |= WM831X_WDOG_RST_SRC;
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}
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev,
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"Failed to unlock security key: %d\n", ret);
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goto err_gpio;
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}
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}
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ret = watchdog_register_device(&driver_data->wdt);
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if (ret != 0) {
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dev_err(wm831x->dev, "watchdog_register_device() failed: %d\n",
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ret);
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goto err_gpio;
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}
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dev_set_drvdata(&pdev->dev, driver_data);
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return 0;
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err_gpio:
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if (driver_data->update_gpio)
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gpio_free(driver_data->update_gpio);
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err_alloc:
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kfree(driver_data);
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err:
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return ret;
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}
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static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
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{
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struct wm831x_wdt_drvdata *driver_data = dev_get_drvdata(&pdev->dev);
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watchdog_unregister_device(&driver_data->wdt);
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if (driver_data->update_gpio)
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gpio_free(driver_data->update_gpio);
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return 0;
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}
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static struct platform_driver wm831x_wdt_driver = {
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.probe = wm831x_wdt_probe,
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.remove = __devexit_p(wm831x_wdt_remove),
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.driver = {
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.name = "wm831x-watchdog",
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},
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};
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static int __init wm831x_wdt_init(void)
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{
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return platform_driver_register(&wm831x_wdt_driver);
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}
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module_init(wm831x_wdt_init);
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static void __exit wm831x_wdt_exit(void)
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{
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platform_driver_unregister(&wm831x_wdt_driver);
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}
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module_exit(wm831x_wdt_exit);
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MODULE_AUTHOR("Mark Brown");
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MODULE_DESCRIPTION("WM831x Watchdog");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:wm831x-watchdog");
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