Message-Id: <1361990168-882-1-git-send-email-ian@slimlogic.co.uk>
Date:	Wed, 27 Feb 2013 18:36:07 +0000
From:	Ian Lartey <ian@...mlogic.co.uk>
To:	linux-kernel@...r.kernel.org
Cc:	linux-watchdog@...r.kernel.org, ldewangan@...dia.com,
	j-keerthy@...com, gg@...mlogic.co.uk, wim@...ana.be,
	grant.likely@...retlab.ca, rob.herring@...xeda.com,
	Ian Lartey <ian@...mlogic.co.uk>
Subject: [PATCH 1/2] watchdog: add Palmas Watchdog support

From: Graeme Gregory <gg@...mlogic.co.uk>

Add support for the Palmas watchdog timer which has a timeout configurable
from 1s to 128s.

Signed-off-by: Graeme Gregory <gg@...mlogic.co.uk>
Signed-off-by: Ian Lartey <ian@...mlogic.co.uk>
---
 drivers/watchdog/palmas_wdt.c |  291 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 291 insertions(+), 0 deletions(-)
 create mode 100644 drivers/watchdog/palmas_wdt.c

diff --git a/drivers/watchdog/palmas_wdt.c b/drivers/watchdog/palmas_wdt.c
new file mode 100644
index 0000000..68cdc1e
--- /dev/null
+++ b/drivers/watchdog/palmas_wdt.c
@@ -0,0 +1,291 @@
+/*
+ * Driver for Watchdog part of Palmas PMIC Chips
+ *
+ * Copyright 2011 Texas Instruments Inc.
+ *
+ * Author: Graeme Gregory <gg@...mlogic.co.uk>
+ * Author: Ian Lartey <ian@...mlogic.co.uk>
+ *
+ * Based on twl4030_wdt.c
+ *
+ * Author: Timo Kokkonen <timo.t.kokkonen at nokia.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/module.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/uaccess.h>
+#include <linux/mfd/palmas.h>
+
+static struct platform_device *palmas_wdt_dev;
+
+struct palmas_wdt {
+	struct palmas *palmas;
+
+	struct miscdevice miscdev;
+	int timer_margin;
+	unsigned long state;
+};
+
+#define PALMAS_WDT_ENABLED	(1<<1)
+
+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 int palmas_wdt_write(struct palmas *palmas, unsigned int data)
+{
+	unsigned int addr;
+
+	addr = PALMAS_BASE_TO_REG(PALMAS_PMU_CONTROL_BASE, PALMAS_WATCHDOG);
+
+	return palmas_write(palmas, PALMAS_PMU_CONTROL_BASE, addr, addr);
+}
+
+static int palmas_wdt_enable(struct palmas_wdt *wdt)
+{
+	return palmas_wdt_write(wdt->palmas,
+			wdt->timer_margin | PALMAS_WATCHDOG_ENABLE);
+}
+
+static int palmas_wdt_disable(struct palmas_wdt *wdt)
+{
+	return palmas_wdt_write(wdt->palmas, wdt->timer_margin);
+}
+
+static int palmas_wdt_set_timeout(struct palmas_wdt *wdt, int timeout)
+{
+	if (timeout < 1 || timeout > 128) {
+		dev_warn(wdt->miscdev.parent,
+			"Timeout can only be in the range [1-128] seconds");
+		return -EINVAL;
+	}
+	wdt->timer_margin = fls(timeout) - 1;
+	return palmas_wdt_enable(wdt);
+}
+
+static ssize_t palmas_wdt_write_fop(struct file *file,
+		const char __user *data, size_t len, loff_t *ppos)
+{
+	struct palmas_wdt *wdt = file->private_data;
+
+	if (len)
+		palmas_wdt_enable(wdt);
+
+	return len;
+}
+
+static long palmas_wdt_ioctl(struct file *file,
+		unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	int new_margin;
+	struct palmas_wdt *wdt = file->private_data;
+	int time = 0;
+
+	static const struct watchdog_info palmas_wd_ident = {
+		.identity = "Palmas Watchdog",
+		.options = WDIOF_SETTIMEOUT,
+		.firmware_version = 0,
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &palmas_wd_ident,
+				sizeof(palmas_wd_ident)) ? -EFAULT : 0;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+
+	case WDIOC_KEEPALIVE:
+		palmas_wdt_enable(wdt);
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_margin, p))
+			return -EFAULT;
+		if (palmas_wdt_set_timeout(wdt, new_margin))
+			return -EINVAL;
+
+		time = 1 << wdt->timer_margin;
+
+		return put_user(time, p);
+
+	case WDIOC_GETTIMEOUT:
+		time = 1 << wdt->timer_margin;
+
+		return put_user(time, p);
+
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static int palmas_wdt_open(struct inode *inode, struct file *file)
+{
+	struct palmas_wdt *wdt = platform_get_drvdata(palmas_wdt_dev);
+
+	/* /dev/watchdog can only be opened once */
+	if (test_and_set_bit(0, &wdt->state))
+		return -EBUSY;
+
+	wdt->state |= PALMAS_WDT_ENABLED;
+	file->private_data = (void *) wdt;
+
+	palmas_wdt_enable(wdt);
+	return nonseekable_open(inode, file);
+}
+
+static int palmas_wdt_release(struct inode *inode, struct file *file)
+{
+	struct palmas_wdt *wdt = file->private_data;
+	if (nowayout) {
+		dev_alert(wdt->miscdev.parent,
+		       "Unexpected close, watchdog still running!\n");
+		palmas_wdt_enable(wdt);
+	} else {
+		if (palmas_wdt_disable(wdt))
+			return -EFAULT;
+		wdt->state &= ~PALMAS_WDT_ENABLED;
+	}
+
+	clear_bit(0, &wdt->state);
+	return 0;
+}
+
+static const struct file_operations palmas_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.open		= palmas_wdt_open,
+	.release	= palmas_wdt_release,
+	.unlocked_ioctl	= palmas_wdt_ioctl,
+	.write		= palmas_wdt_write_fop,
+};
+
+static int palmas_wdt_probe(struct platform_device *pdev)
+{
+	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
+	struct palmas_wdt *wdt;
+	int ret = 0;
+
+	wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->palmas		= palmas;
+	wdt->state		= 0;
+	wdt->timer_margin	= 7;
+	wdt->miscdev.parent	= &pdev->dev;
+	wdt->miscdev.fops	= &palmas_wdt_fops;
+	wdt->miscdev.minor	= WATCHDOG_MINOR;
+	wdt->miscdev.name	= "watchdog";
+
+	platform_set_drvdata(pdev, wdt);
+
+	palmas_wdt_dev = pdev;
+
+	palmas_wdt_disable(wdt);
+
+	ret = misc_register(&wdt->miscdev);
+	if (ret) {
+		dev_err(wdt->miscdev.parent,
+			"Failed to register misc device\n");
+		platform_set_drvdata(pdev, NULL);
+		kfree(wdt);
+		palmas_wdt_dev = NULL;
+		return ret;
+	}
+	return 0;
+}
+
+static int palmas_wdt_remove(struct platform_device *pdev)
+{
+	struct palmas_wdt *wdt = platform_get_drvdata(pdev);
+
+	if (wdt->state & PALMAS_WDT_ENABLED)
+		if (palmas_wdt_disable(wdt))
+			return -EFAULT;
+
+	wdt->state &= ~PALMAS_WDT_ENABLED;
+	misc_deregister(&wdt->miscdev);
+
+	platform_set_drvdata(pdev, NULL);
+	kfree(wdt);
+	palmas_wdt_dev = NULL;
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int palmas_wdt_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct palmas_wdt *wdt = platform_get_drvdata(pdev);
+	if (wdt->state & PALMAS_WDT_ENABLED)
+		return palmas_wdt_disable(wdt);
+
+	return 0;
+}
+
+static int palmas_wdt_resume(struct platform_device *pdev)
+{
+	struct palmas_wdt *wdt = platform_get_drvdata(pdev);
+	if (wdt->state & PALMAS_WDT_ENABLED)
+		return palmas_wdt_enable(wdt);
+
+	return 0;
+}
+#else
+#define palmas_wdt_suspend        NULL
+#define palmas_wdt_resume         NULL
+#endif
+
+static struct of_device_id of_palmas_match_tbl[] = {
+	{ .compatible = "ti,palmas-wdt", },
+	{ /* end */ }
+};
+
+static struct platform_driver palmas_wdt_driver = {
+	.probe = palmas_wdt_probe,
+	.remove = palmas_wdt_remove,
+	.suspend = palmas_wdt_suspend,
+	.resume = palmas_wdt_resume,
+	.driver = {
+		.owner = THIS_MODULE,
+		.of_match_table = of_palmas_match_tbl,
+		.name = "palmas-wdt",
+	},
+};
+
+static int palmas_wdt_init(void)
+{
+	return platform_driver_register(&palmas_wdt_driver);
+}
+module_init(palmas_wdt_init);
+
+static void palmas_wdt_exit(void)
+{
+	platform_driver_unregister(&palmas_wdt_driver);
+}
+module_exit(palmas_wdt_exit);
+
+MODULE_AUTHOR("Graeme Gregory <gg@...mlogic.co.uk>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:palmas-wdt");
+MODULE_DEVICE_TABLE(of, of_palmas_match_tbl);
-- 
1.7.0.4

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