Message-ID: <20081114091827.GL2690@infomag.infomag.iguana.be>
Date:	Fri, 14 Nov 2008 10:18:27 +0100
From:	Wim Van Sebroeck <wim@...ana.be>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [WATCHDOG] v2.6.28-rc5 - add wm8350 watchdog device driver

Hi Linus,

In v2.6.28-rc1 WM8350 regulator support was added.
(See commit da09155ac8d3f04c299b3d82a6ab0df8d03da632).
In the code for the WM8350 device the hooks for it's watchdog were allready foreseen.

The watchdog code was still under review at that time, but it is ok now.
Could you therefor consider adding the watchdog part of this device at this stage still?

Thanks in advance,
Wim.

If yes, Please pull from 'master' branch of
	git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog.git
or if master.kernel.org hasn't synced up yet:
	master.kernel.org:/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog.git

This will update the following files:

 drivers/watchdog/Kconfig      |    7 
 drivers/watchdog/Makefile     |    1 
 drivers/watchdog/wm8350_wdt.c |  329 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 337 insertions(+)

with these Changes:

Author: Mark Brown <broonie@...nsource.wolfsonmicro.com>
Date:   Thu Nov 6 10:56:21 2008 +0000

    [WATCHDOG] Add support for the WM8350 watchdog
    
    This driver implements support for the watchdog functionality provided
    by the Wolfson Microelectronics WM8350, a multi-function audio and
    power management subsystem intended for use in embedded systems. It is
    based on a driver originally written by Graeme Gregory, though it has
    been extensively modified since then.
    
    Use of a GPIO to kick the watchdog is not yet supported.
    
    Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
    Signed-off-by: Wim Van Sebroeck <wim@...ana.be>
    Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>

The Changes can also be looked at on:
	http://www.kernel.org/git/?p=linux/kernel/git/wim/linux-2.6-watchdog.git;a=summary

For completeness, I added the overal diff below.

Greetings,
Wim.

================================================================================
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 4fd3fa5..d5bc085 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -55,6 +55,13 @@ config SOFT_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called softdog.
 
+config WM8350_WATCHDOG
+	tristate "WM8350 watchdog"
+	depends on MFD_WM8350
+	help
+	  Support for the watchdog in the WM8350 AudioPlus PMIC.  When
+	  the watchdog triggers the system will be reset.
+
 # ALPHA Architecture
 
 # ARM Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index e352bbb..02f8993 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -133,4 +133,5 @@ obj-$(CONFIG_WATCHDOG_CP1XXX)		+= cpwd.o
 # XTENSA Architecture
 
 # Architecture Independant
+obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
diff --git a/drivers/watchdog/wm8350_wdt.c b/drivers/watchdog/wm8350_wdt.c
new file mode 100644
index 0000000..2bc0d4d
--- /dev/null
+++ b/drivers/watchdog/wm8350_wdt.c
@@ -0,0 +1,329 @@
+/*
+ * Watchdog driver for the wm8350
+ *
+ * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@...fsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/uaccess.h>
+#include <linux/mfd/wm8350/core.h>
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout,
+		 "Watchdog cannot be stopped once started (default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static unsigned long wm8350_wdt_users;
+static struct miscdevice wm8350_wdt_miscdev;
+static int wm8350_wdt_expect_close;
+static DEFINE_MUTEX(wdt_mutex);
+
+static struct {
+	int time;  /* Seconds */
+	u16 val;   /* To be set in WM8350_SYSTEM_CONTROL_2 */
+} wm8350_wdt_cfgs[] = {
+	{ 1, 0x02 },
+	{ 2, 0x04 },
+	{ 4, 0x05 },
+};
+
+static struct wm8350 *get_wm8350(void)
+{
+	return dev_get_drvdata(wm8350_wdt_miscdev.parent);
+}
+
+static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value)
+{
+	int ret;
+	u16 reg;
+
+	mutex_lock(&wdt_mutex);
+	wm8350_reg_unlock(wm8350);
+
+	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+	reg &= ~WM8350_WDOG_TO_MASK;
+	reg |= value;
+	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
+
+	wm8350_reg_lock(wm8350);
+	mutex_unlock(&wdt_mutex);
+
+	return ret;
+}
+
+static int wm8350_wdt_start(struct wm8350 *wm8350)
+{
+	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 wm8350 *wm8350)
+{
+	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;
+	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
+
+	wm8350_reg_lock(wm8350);
+	mutex_unlock(&wdt_mutex);
+
+	return ret;
+}
+
+static int wm8350_wdt_kick(struct wm8350 *wm8350)
+{
+	int ret;
+	u16 reg;
+
+	mutex_lock(&wdt_mutex);
+
+	reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+	ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
+
+	mutex_unlock(&wdt_mutex);
+
+	return ret;
+}
+
+static int wm8350_wdt_open(struct inode *inode, struct file *file)
+{
+	struct wm8350 *wm8350 = get_wm8350();
+	int ret;
+
+	if (!wm8350)
+		return -ENODEV;
+
+	if (test_and_set_bit(0, &wm8350_wdt_users))
+		return -EBUSY;
+
+	ret = wm8350_wdt_start(wm8350);
+	if (ret != 0)
+		return ret;
+
+	return nonseekable_open(inode, file);
+}
+
+static int wm8350_wdt_release(struct inode *inode, struct file *file)
+{
+	struct wm8350 *wm8350 = get_wm8350();
+
+	if (wm8350_wdt_expect_close)
+		wm8350_wdt_stop(wm8350);
+	else {
+		dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n");
+		wm8350_wdt_kick(wm8350);
+	}
+
+	clear_bit(0, &wm8350_wdt_users);
+
+	return 0;
+}
+
+static ssize_t wm8350_wdt_write(struct file *file,
+				const char __user *data, size_t count,
+				loff_t *ppos)
+{
+	struct wm8350 *wm8350 = get_wm8350();
+	size_t i;
+
+	if (count) {
+		wm8350_wdt_kick(wm8350);
+
+		if (!nowayout) {
+			/* In case it was set long ago */
+			wm8350_wdt_expect_close = 0;
+
+			/* scan to see whether or not we got the magic
+			   character */
+			for (i = 0; i != count; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					wm8350_wdt_expect_close = 42;
+			}
+		}
+	}
+	return count;
+}
+
+static struct watchdog_info ident = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "WM8350 Watchdog",
+};
+
+static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct wm8350 *wm8350 = get_wm8350();
+	int ret = -ENOTTY, time, i;
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	u16 reg;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+		break;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		ret = put_user(0, p);
+		break;
+
+	case WDIOC_SETOPTIONS:
+	{
+		int options;
+
+		if (get_user(options, p))
+			return -EFAULT;
+
+		ret = -EINVAL;
+
+		/* Setting both simultaneously means at least one must fail */
+		if (options == WDIOS_DISABLECARD)
+			ret = wm8350_wdt_start(wm8350);
+
+		if (options == WDIOS_ENABLECARD)
+			ret = wm8350_wdt_stop(wm8350);
+		break;
+	}
+
+	case WDIOC_KEEPALIVE:
+		ret = wm8350_wdt_kick(wm8350);
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		ret = get_user(time, p);
+		if (ret)
+			break;
+
+		if (time == 0) {
+			if (nowayout)
+				ret = -EINVAL;
+			else
+				wm8350_wdt_stop(wm8350);
+			break;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
+			if (wm8350_wdt_cfgs[i].time == time)
+				break;
+		if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
+			ret = -EINVAL;
+		else
+			ret = wm8350_wdt_set_timeout(wm8350,
+						     wm8350_wdt_cfgs[i].val);
+		break;
+
+	case WDIOC_GETTIMEOUT:
+		reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+		reg &= WM8350_WDOG_TO_MASK;
+		for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
+			if (wm8350_wdt_cfgs[i].val == reg)
+				break;
+		if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) {
+			dev_warn(wm8350->dev,
+				 "Unknown watchdog configuration: %x\n", reg);
+			ret = -EINVAL;
+		} else
+			ret = put_user(wm8350_wdt_cfgs[i].time, p);
+
+	}
+
+	return ret;
+}
+
+static const struct file_operations wm8350_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = wm8350_wdt_write,
+	.unlocked_ioctl = wm8350_wdt_ioctl,
+	.open = wm8350_wdt_open,
+	.release = wm8350_wdt_release,
+};
+
+static struct miscdevice wm8350_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &wm8350_wdt_fops,
+};
+
+static int wm8350_wdt_probe(struct platform_device *pdev)
+{
+	struct wm8350 *wm8350 = platform_get_drvdata(pdev);
+
+	if (!wm8350) {
+		dev_err(wm8350->dev, "No driver data supplied\n");
+		return -ENODEV;
+	}
+
+	/* Default to 4s timeout */
+	wm8350_wdt_set_timeout(wm8350, 0x05);
+
+	wm8350_wdt_miscdev.parent = &pdev->dev;
+
+	return misc_register(&wm8350_wdt_miscdev);
+}
+
+static int __exit wm8350_wdt_remove(struct platform_device *pdev)
+{
+	misc_deregister(&wm8350_wdt_miscdev);
+
+	return 0;
+}
+
+static struct platform_driver wm8350_wdt_driver = {
+	.probe = wm8350_wdt_probe,
+	.remove = wm8350_wdt_remove,
+	.driver = {
+		.name = "wm8350-wdt",
+	},
+};
+
+static int __init wm8350_wdt_init(void)
+{
+	return platform_driver_register(&wm8350_wdt_driver);
+}
+module_init(wm8350_wdt_init);
+
+static void __exit wm8350_wdt_exit(void)
+{
+	platform_driver_unregister(&wm8350_wdt_driver);
+}
+module_exit(wm8350_wdt_exit);
+
+MODULE_AUTHOR("Mark Brown");
+MODULE_DESCRIPTION("WM8350 Watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm8350-wdt");
--
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