Message-Id: <20170130165548.40965-3-hsweeten@visionengravers.com>
Date:   Mon, 30 Jan 2017 09:55:48 -0700
From:   H Hartley Sweeten <hsweeten@...ionengravers.com>
To:     linux-watchdog@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        H Hartley Sweeten <hsweeten@...ionengravers.com>,
        Mika Westerberg <mika.westerberg@....fi>,
        Wim Van Sebroeck <wim@...ana.be>,
        Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 2/2] watchdog: ts72xx_wdt: convert driver to watchdog core

Cleanup this driver and convert it to use the watchdog framework API.

Signed-off-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
Cc: Mika Westerberg <mika.westerberg@....fi>
Cc: Wim Van Sebroeck <wim@...ana.be>
Cc: Guenter Roeck <linux@...ck-us.net>
---
 drivers/watchdog/ts72xx_wdt.c | 447 +++++++++---------------------------------
 1 file changed, 93 insertions(+), 354 deletions(-)

diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
index 4b54193..857ab71 100644
--- a/drivers/watchdog/ts72xx_wdt.c
+++ b/drivers/watchdog/ts72xx_wdt.c
@@ -13,413 +13,149 @@
  * warranty of any kind, whether express or implied.
  */
 
-#include <linux/fs.h>
-#include <linux/io.h>
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/miscdevice.h>
-#include <linux/mutex.h>
 #include <linux/platform_device.h>
-#include <linux/slab.h>
+#include <linux/module.h>
 #include <linux/watchdog.h>
-#include <linux/uaccess.h>
-
-#define TS72XX_WDT_FEED_VAL		0x05
-#define TS72XX_WDT_DEFAULT_TIMEOUT	8
-
-static int timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
-module_param(timeout, int, 0);
-MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. "
-			  "(1 <= timeout <= 8, default="
-			  __MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT)
-			  ")");
+#include <linux/io.h>
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
 
-/**
- * struct ts72xx_wdt - watchdog control structure
- * @lock: lock that protects this structure
- * @regval: watchdog timeout value suitable for control register
- * @flags: flags controlling watchdog device state
- * @control_reg: watchdog control register
- * @feed_reg: watchdog feed register
- * @pdev: back pointer to platform dev
- */
-struct ts72xx_wdt {
-	struct mutex	lock;
-	int		regval;
-
-#define TS72XX_WDT_BUSY_FLAG		1
-#define TS72XX_WDT_EXPECT_CLOSE_FLAG	2
-	int		flags;
+/* priv->control_reg */
+#define TS72XX_WDT_CTRL_DISABLE		0x00
+#define TS72XX_WDT_CTRL_250MS		0x01
+#define TS72XX_WDT_CTRL_500MS		0x02
+#define TS72XX_WDT_CTRL_1SEC		0x03
+#define TS72XX_WDT_CTRL_RESERVED	0x04
+#define TS72XX_WDT_CTRL_2SEC		0x05
+#define TS72XX_WDT_CTRL_4SEC		0x06
+#define TS72XX_WDT_CTRL_8SEC		0x07
+
+/* priv->feed_reg */
+#define TS72XX_WDT_FEED_VAL		0x05
 
+struct ts72xx_wdt_priv {
 	void __iomem	*control_reg;
 	void __iomem	*feed_reg;
-
-	struct platform_device *pdev;
+	struct watchdog_device wdd;
+	unsigned char regval;
 };
 
-static struct platform_device *ts72xx_wdt_pdev;
-
-/*
- * TS-72xx Watchdog supports following timeouts (value written
- * to control register):
- *	value	description
- *	-------------------------
- *	0x00	watchdog disabled
- *	0x01	250ms
- *	0x02	500ms
- *	0x03	1s
- *	0x04	reserved
- *	0x05	2s
- *	0x06	4s
- *	0x07	8s
- *
- * Timeouts below 1s are not very usable so we don't
- * allow them at all.
- *
- * We provide two functions that convert between these:
- * timeout_to_regval() and regval_to_timeout().
- */
-static const struct {
-	int	timeout;
-	int	regval;
-} ts72xx_wdt_map[] = {
-	{ 1, 3 },
-	{ 2, 5 },
-	{ 4, 6 },
-	{ 8, 7 },
-};
-
-/**
- * timeout_to_regval() - converts given timeout to control register value
- * @new_timeout: timeout in seconds to be converted
- *
- * Function converts given @new_timeout into valid value that can
- * be programmed into watchdog control register. When conversion is
- * not possible, function returns %-EINVAL.
- */
-static int timeout_to_regval(int new_timeout)
+static int ts72xx_wdt_start(struct watchdog_device *wdd)
 {
-	int i;
+	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	/* first limit it to 1 - 8 seconds */
-	new_timeout = clamp_val(new_timeout, 1, 8);
+	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
+	writeb(priv->regval, priv->control_reg);
 
-	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
-		if (ts72xx_wdt_map[i].timeout >= new_timeout)
-			return ts72xx_wdt_map[i].regval;
-	}
-
-	return -EINVAL;
-}
-
-/**
- * regval_to_timeout() - converts control register value to timeout
- * @regval: control register value to be converted
- *
- * Function converts given @regval to timeout in seconds (1, 2, 4 or 8).
- * If @regval cannot be converted, function returns %-EINVAL.
- */
-static int regval_to_timeout(int regval)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
-		if (ts72xx_wdt_map[i].regval == regval)
-			return ts72xx_wdt_map[i].timeout;
-	}
-
-	return -EINVAL;
-}
-
-/**
- * ts72xx_wdt_kick() - kick the watchdog
- * @wdt: watchdog to be kicked
- *
- * Called with @wdt->lock held.
- */
-static inline void ts72xx_wdt_kick(struct ts72xx_wdt *wdt)
-{
-	__raw_writeb(TS72XX_WDT_FEED_VAL, wdt->feed_reg);
-}
-
-/**
- * ts72xx_wdt_start() - starts the watchdog timer
- * @wdt: watchdog to be started
- *
- * This function programs timeout to watchdog timer
- * and starts it.
- *
- * Called with @wdt->lock held.
- */
-static void ts72xx_wdt_start(struct ts72xx_wdt *wdt)
-{
-	/*
-	 * To program the wdt, it first must be "fed" and
-	 * only after that (within 30 usecs) the configuration
-	 * can be changed.
-	 */
-	ts72xx_wdt_kick(wdt);
-	__raw_writeb((u8)wdt->regval, wdt->control_reg);
-}
-
-/**
- * ts72xx_wdt_stop() - stops the watchdog timer
- * @wdt: watchdog to be stopped
- *
- * Called with @wdt->lock held.
- */
-static void ts72xx_wdt_stop(struct ts72xx_wdt *wdt)
-{
-	ts72xx_wdt_kick(wdt);
-	__raw_writeb(0, wdt->control_reg);
+	return 0;
 }
 
-static int ts72xx_wdt_open(struct inode *inode, struct file *file)
+static int ts72xx_wdt_stop(struct watchdog_device *wdd)
 {
-	struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
-	int regval;
-
-	/*
-	 * Try to convert default timeout to valid register
-	 * value first.
-	 */
-	regval = timeout_to_regval(timeout);
-	if (regval < 0) {
-		dev_err(&wdt->pdev->dev,
-			"failed to convert timeout (%d) to register value\n",
-			timeout);
-		return regval;
-	}
-
-	if (mutex_lock_interruptible(&wdt->lock))
-		return -ERESTARTSYS;
-
-	if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
-		mutex_unlock(&wdt->lock);
-		return -EBUSY;
-	}
+	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	wdt->flags = TS72XX_WDT_BUSY_FLAG;
-	wdt->regval = regval;
-	file->private_data = wdt;
+	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
+	writeb(TS72XX_WDT_CTRL_DISABLE, priv->control_reg);
 
-	ts72xx_wdt_start(wdt);
-
-	mutex_unlock(&wdt->lock);
-	return nonseekable_open(inode, file);
+	return 0;
 }
 
-static int ts72xx_wdt_release(struct inode *inode, struct file *file)
+static int ts72xx_wdt_ping(struct watchdog_device *wdd)
 {
-	struct ts72xx_wdt *wdt = file->private_data;
-
-	if (mutex_lock_interruptible(&wdt->lock))
-		return -ERESTARTSYS;
-
-	if ((wdt->flags & TS72XX_WDT_EXPECT_CLOSE_FLAG) != 0) {
-		ts72xx_wdt_stop(wdt);
-	} else {
-		dev_warn(&wdt->pdev->dev,
-			 "TS-72XX WDT device closed unexpectly. "
-			 "Watchdog timer will not stop!\n");
-		/*
-		 * Kick it one more time, to give userland some time
-		 * to recover (for example, respawning the kicker
-		 * daemon).
-		 */
-		ts72xx_wdt_kick(wdt);
-	}
+	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	wdt->flags = 0;
+	writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
 
-	mutex_unlock(&wdt->lock);
 	return 0;
 }
 
-static ssize_t ts72xx_wdt_write(struct file *file,
-				const char __user *data,
-				size_t len,
-				loff_t *ppos)
+static int ts72xx_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
 {
-	struct ts72xx_wdt *wdt = file->private_data;
-
-	if (!len)
-		return 0;
-
-	if (mutex_lock_interruptible(&wdt->lock))
-		return -ERESTARTSYS;
-
-	ts72xx_wdt_kick(wdt);
-
-	/*
-	 * Support for magic character closing. User process
-	 * writes 'V' into the device, just before it is closed.
-	 * This means that we know that the wdt timer can be
-	 * stopped after user closes the device.
-	 */
-	if (!nowayout) {
-		int i;
-
-		for (i = 0; i < len; i++) {
-			char c;
-
-			/* In case it was set long ago */
-			wdt->flags &= ~TS72XX_WDT_EXPECT_CLOSE_FLAG;
-
-			if (get_user(c, data + i)) {
-				mutex_unlock(&wdt->lock);
-				return -EFAULT;
-			}
-			if (c == 'V') {
-				wdt->flags |= TS72XX_WDT_EXPECT_CLOSE_FLAG;
-				break;
-			}
-		}
-	}
-
-	mutex_unlock(&wdt->lock);
-	return len;
-}
+	struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-static const struct watchdog_info winfo = {
-	.options		= WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
-				  WDIOF_MAGICCLOSE,
-	.firmware_version	= 1,
-	.identity		= "TS-72XX WDT",
-};
-
-static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
-			     unsigned long arg)
-{
-	struct ts72xx_wdt *wdt = file->private_data;
-	void __user *argp = (void __user *)arg;
-	int __user *p = (int __user *)argp;
-	int error = 0;
-
-	if (mutex_lock_interruptible(&wdt->lock))
-		return -ERESTARTSYS;
-
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		if (copy_to_user(argp, &winfo, sizeof(winfo)))
-			error = -EFAULT;
+	switch (to) {
+	case 1:
+		priv->regval = TS72XX_WDT_CTRL_1SEC;
 		break;
-
-	case WDIOC_GETSTATUS:
-	case WDIOC_GETBOOTSTATUS:
-		error = put_user(0, p);
+	case 2:
+		priv->regval = TS72XX_WDT_CTRL_2SEC;
 		break;
-
-	case WDIOC_KEEPALIVE:
-		ts72xx_wdt_kick(wdt);
+	case 4:
+		priv->regval = TS72XX_WDT_CTRL_4SEC;
 		break;
-
-	case WDIOC_SETOPTIONS: {
-		int options;
-
-		error = get_user(options, p);
-		if (error)
-			break;
-
-		error = -EINVAL;
-
-		if ((options & WDIOS_DISABLECARD) != 0) {
-			ts72xx_wdt_stop(wdt);
-			error = 0;
-		}
-		if ((options & WDIOS_ENABLECARD) != 0) {
-			ts72xx_wdt_start(wdt);
-			error = 0;
-		}
-
+	case 8:
+		priv->regval = TS72XX_WDT_CTRL_8SEC;
 		break;
+	default:
+		return -EINVAL;
 	}
 
-	case WDIOC_SETTIMEOUT: {
-		int new_timeout;
-		int regval;
-
-		error = get_user(new_timeout, p);
-		if (error)
-			break;
-
-		regval = timeout_to_regval(new_timeout);
-		if (regval < 0) {
-			error = regval;
-			break;
-		}
-		ts72xx_wdt_stop(wdt);
-		wdt->regval = regval;
-		ts72xx_wdt_start(wdt);
-
-		/*FALLTHROUGH*/
-	}
-
-	case WDIOC_GETTIMEOUT:
-		error = put_user(regval_to_timeout(wdt->regval), p);
-		break;
+	wdd->timeout = to;
 
-	default:
-		error = -ENOTTY;
-		break;
+	if (watchdog_active(wdd)) {
+		ts72xx_wdt_stop(wdd);
+		ts72xx_wdt_start(wdd);
 	}
 
-	mutex_unlock(&wdt->lock);
-	return error;
+	return 0;
 }
 
-static const struct file_operations ts72xx_wdt_fops = {
-	.owner		= THIS_MODULE,
-	.llseek		= no_llseek,
-	.open		= ts72xx_wdt_open,
-	.release	= ts72xx_wdt_release,
-	.write		= ts72xx_wdt_write,
-	.unlocked_ioctl	= ts72xx_wdt_ioctl,
+static const struct watchdog_info ts72xx_wdt_ident = {
+	.options		= WDIOF_KEEPALIVEPING |
+				  WDIOF_SETTIMEOUT |
+				  WDIOF_MAGICCLOSE,
+	.firmware_version	= 1,
+	.identity		= "TS-72XX WDT",
 };
 
-static struct miscdevice ts72xx_wdt_miscdev = {
-	.minor		= WATCHDOG_MINOR,
-	.name		= "watchdog",
-	.fops		= &ts72xx_wdt_fops,
+static struct watchdog_ops ts72xx_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= ts72xx_wdt_start,
+	.stop		= ts72xx_wdt_stop,
+	.ping		= ts72xx_wdt_ping,
+	.set_timeout	= ts72xx_wdt_settimeout,
 };
 
 static int ts72xx_wdt_probe(struct platform_device *pdev)
 {
-	struct ts72xx_wdt *wdt;
-	struct resource *r1, *r2;
-	int error = 0;
+	struct ts72xx_wdt_priv *priv;
+	struct watchdog_device *wdd;
+	struct resource *res;
+	int ret;
 
-	wdt = devm_kzalloc(&pdev->dev, sizeof(struct ts72xx_wdt), GFP_KERNEL);
-	if (!wdt)
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
 		return -ENOMEM;
 
-	r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	wdt->control_reg = devm_ioremap_resource(&pdev->dev, r1);
-	if (IS_ERR(wdt->control_reg))
-		return PTR_ERR(wdt->control_reg);
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->control_reg = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->control_reg))
+		return PTR_ERR(priv->control_reg);
 
-	r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-	wdt->feed_reg = devm_ioremap_resource(&pdev->dev, r2);
-	if (IS_ERR(wdt->feed_reg))
-		return PTR_ERR(wdt->feed_reg);
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	priv->feed_reg = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->feed_reg))
+		return PTR_ERR(priv->feed_reg);
 
-	platform_set_drvdata(pdev, wdt);
-	ts72xx_wdt_pdev = pdev;
-	wdt->pdev = pdev;
-	mutex_init(&wdt->lock);
+	wdd = &priv->wdd;
+	wdd->info = &ts72xx_wdt_ident;
+	wdd->ops = &ts72xx_wdt_ops;
+	wdd->min_timeout = 1;
+	wdd->max_timeout = 8;
+	wdd->timeout = 8;
+	wdd->parent = &pdev->dev;
 
-	/* make sure that the watchdog is disabled */
-	ts72xx_wdt_stop(wdt);
+	watchdog_set_nowayout(wdd, nowayout);
 
-	error = misc_register(&ts72xx_wdt_miscdev);
-	if (error) {
-		dev_err(&pdev->dev, "failed to register miscdev\n");
-		return error;
-	}
+	watchdog_set_drvdata(wdd, priv);
+
+	ret = watchdog_register_device(wdd);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, priv);
 
 	dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
 
@@ -428,7 +164,10 @@ static int ts72xx_wdt_probe(struct platform_device *pdev)
 
 static int ts72xx_wdt_remove(struct platform_device *pdev)
 {
-	misc_deregister(&ts72xx_wdt_miscdev);
+	struct ts72xx_wdt_priv *priv = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&priv->wdd);
+
 	return 0;
 }
 
-- 
2.10.0

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