Message-ID: <1312552311.5572.142.camel@L-0532.kpit.com>
Date:	Fri, 5 Aug 2011 19:21:51 +0530
From:	ashishj3 <ashish.jangam@...tcummins.com>
To:	<wim@...ana.be>
CC:	<linux-kernel@...r.kernel.org>, Dajun <dajun.chen@...semi.com>
Subject: [PATCH v2 07/11] Watchdog: DA9052 watchdog support

This driver adds support for the watchdog functionality provided by the Dialog
Semiconductor DA9052 PMIC chip.

Signed-off-by: David Dajun Chen <dchen@...semi.com>
Signed-off-by: Ashish Jangam <ashish.jangam@...tcummins.com>
---
Changes since V2:
- Code restructured for simplicty.
- Add watchdog documentation.
- Remove Auto strobing feature.
- Remove strobe filtering flag.
---
 Documentation/watchdog/watchdog-parameters.txt |    5 +
 drivers/watchdog/Kconfig                       |    6 +
 drivers/watchdog/Makefile                      |    1 +
 drivers/watchdog/da9052_wdt.c                  |  338 ++++++++++++++++++++++++
 4 files changed, 350 insertions(+), 0 deletions(-)
 create mode 100755 drivers/watchdog/da9052_wdt.c
diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
index 17ddd82..04fddba 100644
--- a/Documentation/watchdog/watchdog-parameters.txt
+++ b/Documentation/watchdog/watchdog-parameters.txt
@@ -78,6 +78,11 @@ wd0_timeout: Default watchdog0 timeout in 1/10secs
 wd1_timeout: Default watchdog1 timeout in 1/10secs
 wd2_timeout: Default watchdog2 timeout in 1/10secs
 -------------------------------------------------
+da9052wdt:
+timeout: Watchdog timeout in seconds. 2<= timeout <=131, default=2.048s
+nowayout: Watchdog cannot be stopped once started
+	(default=kernel config parameter)
+-------------------------------------------------
 davinci_wdt:
 heartbeat: Watchdog heartbeat period in seconds from 1 to 600, default 60
 -------------------------------------------------
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 86b0735..9ffa6d7 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -63,6 +63,12 @@ config SOFT_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called softdog.
 
+config DA9052_WATCHDOG
+	tristate "Dialog DA9052 Watchdog"
+	depends on PMIC_DA9052
+	help
+	  Support for the watchdog in the DA9052 PMIC.
+
 config WM831X_WATCHDOG
 	tristate "WM831x watchdog"
 	depends on MFD_WM831X
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 55bd574..b047722 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -166,4 +166,5 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o
 obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
 obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
 obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
+obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
diff --git a/drivers/watchdog/da9052_wdt.c b/drivers/watchdog/da9052_wdt.c
new file mode 100755
index 0000000..546f0d2
--- /dev/null
+++ b/drivers/watchdog/da9052_wdt.c
@@ -0,0 +1,338 @@
+/*
+ * System monitoring driver for DA9052 PMICs.
+ *
+ * Copyright(c) 2011 Dialog Semiconductor Ltd.
+ *
+ * Author: Dajun Chen <dchen@...semi.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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <linux/time.h>
+#include <linux/watchdog.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+
+#include <linux/mfd/da9052/reg.h>
+#include <linux/mfd/da9052/da9052.h>
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+static int wdt_state = WDIOS_DISABLECARD;
+static struct miscdevice da9052_wdt_miscdev;
+static unsigned long da9052_wdt_users;
+static int da9052_wdt_expect_close;
+struct da9052 *da9052;
+static DEFINE_MUTEX(wdt_mutex);
+
+static struct {
+	u8 reg_val;
+	int time;  /* Seconds */
+} da9052_wdt_maps[] = {
+	{ 1, 2 },
+	{ 2, 4 },
+	{ 3, 8 },
+	{ 4, 16 },
+	{ 5, 32 },
+	{ 5, 33 },  /* Actual time  32.768s so included both 32s and 33s */
+	{ 6, 65 },
+	{ 6, 66 },  /* Actual time 65.536s so include both, 65s and 66s */
+	{ 7, 131 },
+};
+
+static int da9052_wdt_set_timeout(struct da9052 *da9052, unsigned char timeout)
+{
+	int ret;
+
+	/* Disable the Watchdog timer for 150us before changing the
+	*  time out value
+	*/
+	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+				DA9052_CONTROLD_TWDSCALE, 0);
+	if (ret < 0) {
+		dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n",
+			ret);
+		return ret;
+	}
+
+	udelay(150);
+
+	/* Set the desired timeout */
+	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+				DA9052_CONTROLD_TWDSCALE, timeout);
+	if (ret < 0) {
+		dev_err(da9052->dev, "Failed to update timescale bit, %d\n",
+			ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int da9052_wdt_start(struct da9052 *da9052)
+{
+	int ret = 0;
+
+	mutex_lock(&wdt_mutex);
+
+	if (wdt_state == WDIOS_DISABLECARD) {
+		/* Default 2.048s */
+		ret = da9052_wdt_set_timeout(da9052, 1);
+		if (ret <= 0)
+			goto err;
+
+		wdt_state = WDIOS_ENABLECARD;
+	}
+
+err:
+	mutex_unlock(&wdt_mutex);
+	return ret;
+}
+
+static int da9052_wdt_stop(struct da9052 *da9052)
+{
+	int ret = 0;
+
+	mutex_lock(&wdt_mutex);
+
+	if (wdt_state == WDIOS_ENABLECARD) {
+		ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+					DA9052_CONTROLD_TWDSCALE, 0);
+		if (ret < 0) {
+			dev_err(da9052->dev,
+				"Failed to disable watchdog bit strobe bit, %d\n",
+				ret);
+			goto err;
+		}
+
+		wdt_state = WDIOS_DISABLECARD;
+	}
+
+err:
+	mutex_unlock(&wdt_mutex);
+	return ret;
+}
+
+static void da9052_wdt_strobe(struct da9052 *da9052)
+{
+	int ret;
+
+	if (wdt_state == WDIOS_ENABLECARD) {
+		ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+					DA9052_CONTROLD_WATCHDOG, 1 << 7);
+		if (ret < 0) {
+			dev_err(da9052->dev,
+				"Failed to update watchdog strobe bit, %d\n",
+				ret);
+			return;
+		}
+	}
+}
+
+static int da9052_wdt_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	if (test_and_set_bit(0, &da9052_wdt_users))
+		return -EBUSY;
+
+	ret = da9052_wdt_start(da9052);
+	if (ret < 0)
+		return ret;
+
+	return nonseekable_open(inode, file);
+}
+
+static int da9052_wdt_release(struct inode *inode, struct file *file)
+{
+	int ret = 0;
+
+	if (da9052_wdt_expect_close == 42)
+		ret = da9052_wdt_stop(da9052);
+	else
+		da9052_wdt_strobe(da9052);
+
+	da9052_wdt_expect_close = 0;
+	clear_bit(0, &da9052_wdt_users);
+
+	return ret;
+}
+
+static struct watchdog_info da9052_wdt_info = {
+	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	.identity	= "DA9052 Watchdog",
+};
+
+static long da9052_wdt_ioctl(struct file *file, uint cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int ret = 0, timeout, i, __user *p = argp;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		ret = copy_to_user(argp, &da9052_wdt_info,
+				   sizeof(da9052_wdt_info)) ? -EFAULT : 0;
+		break;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		ret = put_user(0, p);
+		break;
+	case WDIOC_SETOPTIONS:
+	{
+		int options;
+		ret = get_user(options, p);
+		if (ret)
+			break;
+
+		if (options == WDIOS_ENABLECARD)
+			ret = da9052_wdt_start(da9052);
+
+		if (options == WDIOS_DISABLECARD)
+			ret = da9052_wdt_stop(da9052);
+
+		break;
+	}
+	case WDIOC_KEEPALIVE:
+		da9052_wdt_strobe(da9052);
+		break;
+	case WDIOC_SETTIMEOUT:
+		ret = get_user(timeout, p);
+		if (ret)
+			break;
+
+		for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
+			if (da9052_wdt_maps[i].time == timeout)
+				break;
+		if (i == ARRAY_SIZE(da9052_wdt_maps))
+			ret = -EINVAL;
+		else
+			ret = da9052_wdt_set_timeout(da9052,
+						     da9052_wdt_maps[i].reg_val);
+
+		break;
+	case WDIOC_GETTIMEOUT:
+		ret = da9052_reg_read(da9052, DA9052_CONTROL_D_REG);
+		if (ret < 0)
+			break;
+
+		ret &= DA9052_CONTROLD_TWDSCALE;
+		for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++)
+			if (da9052_wdt_maps[i].reg_val == ret)
+				break;
+		if (i == ARRAY_SIZE(da9052_wdt_maps))
+			ret = -EINVAL;
+		else
+			ret = put_user(da9052_wdt_maps[i].time, p);
+
+		break;
+	default:
+		return -ENOTTY;
+	}
+
+	return ret;
+}
+
+static ssize_t da9052_wdt_write(struct file *file,
+				 const char __user *data, size_t count,
+				 loff_t *ppos)
+{
+	size_t i;
+
+	/* Check the magic character 'V' and reload the timer */
+	if (count) {
+		if (!nowayout) {
+			da9052_wdt_expect_close = 0;
+
+			/* scan for magic character */
+			for (i = 0; i != count; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					da9052_wdt_expect_close = 42;
+			}
+		/* someone wrote to us, we should reload the timer */
+		da9052_wdt_strobe(da9052);
+		}
+	}
+	return count;
+}
+
+static const struct file_operations da9052_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.unlocked_ioctl	= da9052_wdt_ioctl,
+	.write		= da9052_wdt_write,
+	.open		= da9052_wdt_open,
+	.release	= da9052_wdt_release,
+};
+
+static struct miscdevice da9052_wdt_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "da9052-wdt",
+	.fops		= &da9052_wdt_fops,
+};
+
+static int __devinit da9052_wdt_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct da9052 *da9052;
+
+	da9052 = dev_get_drvdata(pdev->dev.parent);
+
+	ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG,
+				DA9052_CONTROLD_TWDSCALE, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n",
+			ret);
+		return ret;
+	}
+
+	da9052_wdt_miscdev.parent = &pdev->dev;
+
+	ret = misc_register(&da9052_wdt_miscdev);
+
+	return ret;
+}
+
+static int __devexit da9052_wdt_remove(struct platform_device *dev)
+{
+	misc_deregister(&da9052_wdt_miscdev);
+
+	return 0;
+}
+
+static struct platform_driver da9052_wdt_driver = {
+	.probe = da9052_wdt_probe,
+	.remove = __devexit_p(da9052_wdt_remove),
+	.driver = {
+		.name	= "da9052-wdt",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init da9052_wdt_init(void)
+{
+	return platform_driver_register(&da9052_wdt_driver);
+}
+module_init(da9052_wdt_init);
+
+static void __exit da9052_wdt_exit(void)
+{
+	platform_driver_unregister(&da9052_wdt_driver);
+}
+module_exit(da9052_wdt_exit);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@...semi.com>");
+MODULE_DESCRIPTION("DA9052 SM Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ret-wdt");


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