[PATCH v3] watchdog: Convert jz4740_wdt driver to watchdog core

[Axel Lin <axel.lin@gmail.com>]

This patch converts jz4740_wdt driver to use watchdog core APIs.
Also use devm_* APIs to save a few error handling code.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Paul Cercueil <paul@crapouillou.net>
---
v3: - Remove unused define for WDT_IN_USE and WDT_OK_TO_CLOSE
    - Remove mem from struct jz4740_wdt_drvdata

v2: Address all the comments by Wolfram.
    - Remove unneed header file inclusion
    - Drop 'heartbeat' usage in jz4740_wdt_set_heartbeat and jz4740_wdt_start
    - Init wdt_dev->timeout in probe using the global 'heartbeat'
    - Remove unneed pointer check for drvdata->mem

 drivers/watchdog/Kconfig      |    1 +
 drivers/watchdog/jz4740_wdt.c |  257 +++++++++++++----------------------------
 2 files changed, 84 insertions(+), 174 deletions(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 2c89da6..a297f01 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -965,6 +965,7 @@ config INDYDOG
 config JZ4740_WDT
 	tristate "Ingenic jz4740 SoC hardware watchdog"
 	depends on MACH_JZ4740
+	select WATCHDOG_CORE
 	help
 	  Hardware driver for the built-in watchdog timer on Ingenic jz4740 SoCs.
 
diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c
index 17ef300..792e9dd 100644
--- a/drivers/watchdog/jz4740_wdt.c
+++ b/drivers/watchdog/jz4740_wdt.c
@@ -17,18 +17,15 @@
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
-#include <linux/fs.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/init.h>
-#include <linux/bitops.h>
 #include <linux/platform_device.h>
-#include <linux/spinlock.h>
-#include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/device.h>
 #include <linux/clk.h>
 #include <linux/slab.h>
+#include <linux/err.h>
 
 #include <asm/mach-jz4740/timer.h>
 
@@ -41,9 +38,6 @@
 #define JZ_WDT_CLOCK_RTC  0x2
 #define JZ_WDT_CLOCK_EXT  0x4
 
-#define WDT_IN_USE        0
-#define WDT_OK_TO_CLOSE   1
-
 #define JZ_WDT_CLOCK_DIV_SHIFT   3
 
 #define JZ_WDT_CLOCK_DIV_1    (0 << JZ_WDT_CLOCK_DIV_SHIFT)
@@ -56,32 +50,44 @@
 #define DEFAULT_HEARTBEAT 5
 #define MAX_HEARTBEAT     2048
 
-static struct {
-	void __iomem *base;
-	struct resource	*mem;
-	struct clk *rtc_clk;
-	unsigned long status;
-} jz4740_wdt;
+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 heartbeat = DEFAULT_HEARTBEAT;
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+		"Watchdog heartbeat period in seconds from 1 to "
+		__MODULE_STRING(MAX_HEARTBEAT) ", default "
+		__MODULE_STRING(DEFAULT_HEARTBEAT));
 
+struct jz4740_wdt_drvdata {
+	struct watchdog_device wdt;
+	void __iomem *base;
+	struct clk *rtc_clk;
+};
 
-static void jz4740_wdt_service(void)
+static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
 {
-	writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
+	struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+	writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
+	return 0;
 }
 
-static void jz4740_wdt_set_heartbeat(int new_heartbeat)
+static int jz4740_wdt_set_heartbeat(struct watchdog_device *wdt_dev,
+				    unsigned int new_heartbeat)
 {
+	struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 	unsigned int rtc_clk_rate;
 	unsigned int timeout_value;
 	unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
 
-	heartbeat = new_heartbeat;
+	rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
 
-	rtc_clk_rate = clk_get_rate(jz4740_wdt.rtc_clk);
-
-	timeout_value = rtc_clk_rate * heartbeat;
+	timeout_value = rtc_clk_rate * new_heartbeat;
 	while (timeout_value > 0xffff) {
 		if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
 			/* Requested timeout too high;
@@ -93,199 +99,109 @@ static void jz4740_wdt_set_heartbeat(int new_heartbeat)
 		clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
 	}
 
-	writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
-	writew(clock_div, jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);
+	writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
+	writew(clock_div, drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
 
-	writew((u16)timeout_value, jz4740_wdt.base + JZ_REG_WDT_TIMER_DATA);
-	writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
+	writew((u16)timeout_value, drvdata->base + JZ_REG_WDT_TIMER_DATA);
+	writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
 	writew(clock_div | JZ_WDT_CLOCK_RTC,
-		jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);
-
-	writeb(0x1, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
-}
+		drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
 
-static void jz4740_wdt_enable(void)
-{
-	jz4740_timer_enable_watchdog();
-	jz4740_wdt_set_heartbeat(heartbeat);
-}
+	writeb(0x1, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
 
-static void jz4740_wdt_disable(void)
-{
-	jz4740_timer_disable_watchdog();
-	writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
+	return 0;
 }
 
-static int jz4740_wdt_open(struct inode *inode, struct file *file)
+static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
 {
-	if (test_and_set_bit(WDT_IN_USE, &jz4740_wdt.status))
-		return -EBUSY;
-
-	jz4740_wdt_enable();
+	jz4740_timer_enable_watchdog();
+	jz4740_wdt_set_heartbeat(wdt_dev, wdt_dev->timeout);
 
-	return nonseekable_open(inode, file);
+	return 0;
 }
 
-static ssize_t jz4740_wdt_write(struct file *file, const char *data,
-		size_t len, loff_t *ppos)
+static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
 {
-	if (len) {
-		size_t i;
-
-		clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
-		for (i = 0; i != len; i++) {
-			char c;
+	struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 
-			if (get_user(c, data + i))
-				return -EFAULT;
-
-			if (c == 'V')
-				set_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
-		}
-		jz4740_wdt_service();
-	}
+	jz4740_timer_disable_watchdog();
+	writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
 
-	return len;
+	return 0;
 }
 
-static const struct watchdog_info ident = {
-	.options = WDIOF_KEEPALIVEPING,
+static const struct watchdog_info jz4740_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 	.identity = "jz4740 Watchdog",
 };
 
-static long jz4740_wdt_ioctl(struct file *file,
-					unsigned int cmd, unsigned long arg)
-{
-	int ret = -ENOTTY;
-	int heartbeat_seconds;
-
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		ret = copy_to_user((struct watchdog_info *)arg, &ident,
-				sizeof(ident)) ? -EFAULT : 0;
-		break;
-
-	case WDIOC_GETSTATUS:
-	case WDIOC_GETBOOTSTATUS:
-		ret = put_user(0, (int *)arg);
-		break;
-
-	case WDIOC_KEEPALIVE:
-		jz4740_wdt_service();
-		return 0;
-
-	case WDIOC_SETTIMEOUT:
-		if (get_user(heartbeat_seconds, (int __user *)arg))
-			return -EFAULT;
-
-		jz4740_wdt_set_heartbeat(heartbeat_seconds);
-		return 0;
-
-	case WDIOC_GETTIMEOUT:
-		return put_user(heartbeat, (int *)arg);
-
-	default:
-		break;
-	}
-
-	return ret;
-}
-
-static int jz4740_wdt_release(struct inode *inode, struct file *file)
-{
-	jz4740_wdt_service();
-
-	if (test_and_clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status))
-		jz4740_wdt_disable();
-
-	clear_bit(WDT_IN_USE, &jz4740_wdt.status);
-	return 0;
-}
-
-static const struct file_operations jz4740_wdt_fops = {
+static const struct watchdog_ops jz4740_wdt_ops = {
 	.owner = THIS_MODULE,
-	.llseek = no_llseek,
-	.write = jz4740_wdt_write,
-	.unlocked_ioctl = jz4740_wdt_ioctl,
-	.open = jz4740_wdt_open,
-	.release = jz4740_wdt_release,
-};
-
-static struct miscdevice jz4740_wdt_miscdev = {
-	.minor = WATCHDOG_MINOR,
-	.name = "watchdog",
-	.fops = &jz4740_wdt_fops,
+	.start = jz4740_wdt_start,
+	.stop = jz4740_wdt_stop,
+	.ping = jz4740_wdt_ping,
+	.set_timeout = jz4740_wdt_set_heartbeat,
 };
 
 static int __devinit jz4740_wdt_probe(struct platform_device *pdev)
 {
-	int ret = 0, size;
-	struct resource *res;
-	struct device *dev = &pdev->dev;
-
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (res == NULL) {
-		dev_err(dev, "failed to get memory region resource\n");
-		return -ENXIO;
+	struct jz4740_wdt_drvdata *drvdata;
+	struct watchdog_device *jz4740_wdt;
+	struct resource	*res;
+	int ret;
+
+	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct jz4740_wdt_drvdata),
+			       GFP_KERNEL);
+	if (!drvdata) {
+		dev_err(&pdev->dev, "Unable to alloacate watchdog device\n");
+		return -ENOMEM;
 	}
 
-	size = resource_size(res);
-	jz4740_wdt.mem = request_mem_region(res->start, size, pdev->name);
-	if (jz4740_wdt.mem == NULL) {
-		dev_err(dev, "failed to get memory region\n");
-		return -EBUSY;
-	}
+	jz4740_wdt = &drvdata->wdt;
+	jz4740_wdt->info = &jz4740_wdt_info;
+	jz4740_wdt->ops = &jz4740_wdt_ops;
+	jz4740_wdt->timeout = heartbeat;
+	watchdog_set_nowayout(jz4740_wdt, nowayout);
+	watchdog_set_drvdata(jz4740_wdt, drvdata);
 
-	jz4740_wdt.base = ioremap_nocache(res->start, size);
-	if (jz4740_wdt.base == NULL) {
-		dev_err(dev, "failed to map memory region\n");
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	drvdata->base = devm_request_and_ioremap(&pdev->dev, res);
+	if (drvdata->base == NULL) {
 		ret = -EBUSY;
-		goto err_release_region;
+		goto err_out;
 	}
 
-	jz4740_wdt.rtc_clk = clk_get(NULL, "rtc");
-	if (IS_ERR(jz4740_wdt.rtc_clk)) {
-		dev_err(dev, "cannot find RTC clock\n");
-		ret = PTR_ERR(jz4740_wdt.rtc_clk);
-		goto err_iounmap;
+	drvdata->rtc_clk = clk_get(NULL, "rtc");
+	if (IS_ERR(drvdata->rtc_clk)) {
+		dev_err(&pdev->dev, "cannot find RTC clock\n");
+		ret = PTR_ERR(drvdata->rtc_clk);
+		goto err_out;
 	}
 
-	ret = misc_register(&jz4740_wdt_miscdev);
-	if (ret < 0) {
-		dev_err(dev, "cannot register misc device\n");
+	ret = watchdog_register_device(&drvdata->wdt);
+	if (ret < 0)
 		goto err_disable_clk;
-	}
 
+	platform_set_drvdata(pdev, drvdata);
 	return 0;
 
 err_disable_clk:
-	clk_put(jz4740_wdt.rtc_clk);
-err_iounmap:
-	iounmap(jz4740_wdt.base);
-err_release_region:
-	release_mem_region(jz4740_wdt.mem->start,
-			resource_size(jz4740_wdt.mem));
+	clk_put(drvdata->rtc_clk);
+err_out:
 	return ret;
 }
 
-
 static int __devexit jz4740_wdt_remove(struct platform_device *pdev)
 {
-	jz4740_wdt_disable();
-	misc_deregister(&jz4740_wdt_miscdev);
-	clk_put(jz4740_wdt.rtc_clk);
-
-	iounmap(jz4740_wdt.base);
-	jz4740_wdt.base = NULL;
+	struct jz4740_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
 
-	release_mem_region(jz4740_wdt.mem->start,
-				resource_size(jz4740_wdt.mem));
-	jz4740_wdt.mem = NULL;
+	jz4740_wdt_stop(&drvdata->wdt);
+	watchdog_unregister_device(&drvdata->wdt);
+	clk_put(drvdata->rtc_clk);
 
 	return 0;
 }
 
-
 static struct platform_driver jz4740_wdt_driver = {
 	.probe = jz4740_wdt_probe,
 	.remove = __devexit_p(jz4740_wdt_remove),
@@ -299,13 +215,6 @@ module_platform_driver(jz4740_wdt_driver);
 
 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
 MODULE_DESCRIPTION("jz4740 Watchdog Driver");
-
-module_param(heartbeat, int, 0);
-MODULE_PARM_DESC(heartbeat,
-		"Watchdog heartbeat period in seconds from 1 to "
-		__MODULE_STRING(MAX_HEARTBEAT) ", default "
-		__MODULE_STRING(DEFAULT_HEARTBEAT));
-
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 MODULE_ALIAS("platform:jz4740-wdt");
-- 
1.7.5.4