[PATCH 0/2] ep93xx: TS-72xx watchdog driver

[PATCH 0/2] ep93xx: TS-72xx watchdog driver

[Mika Westerberg]

Hi,

Technologic Systems TS-72xx SBCs (TS-7200, TS-7250 and TS-7260) have
watchdog timer that is implemented in external CPLD chip. This set of
patches provide implementation of watchdog driver for that chip.

I tested this on TS-7260 board.

Thanks,
MW

Mika Westerberg (2):
  ep93xx: implemented watchdog timer driver for TS-72xx SBCs
  ep93xx: added platform side support for TS-72xx WDT driver

 arch/arm/mach-ep93xx/include/mach/ts72xx.h |    2 +
 arch/arm/mach-ep93xx/ts72xx.c              |   21 ++
 drivers/watchdog/Kconfig                   |   11 +
 drivers/watchdog/Makefile                  |    1 +
 drivers/watchdog/ts72xx_wdt.c              |  458 ++++++++++++++++++++++++++++
 5 files changed, 493 insertions(+), 0 deletions(-)
 create mode 100644 drivers/watchdog/ts72xx_wdt.c

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Mika Westerberg]

Technologic Systems TS-72xx SBCs have external glue logic
CPLD which includes watchdog timer. This driver implements
kernel support for that.

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
---
 drivers/watchdog/Kconfig      |   11 +
 drivers/watchdog/Makefile     |    1 +
 drivers/watchdog/ts72xx_wdt.c |  458 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 470 insertions(+), 0 deletions(-)
 create mode 100644 drivers/watchdog/ts72xx_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 3711b88..5204612 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -289,6 +289,17 @@ config ADX_WATCHDOG
 	  Say Y here if you want support for the watchdog timer on Avionic
 	  Design Xanthos boards.
 
+config TS72XX_WATCHDOG
+	tristate "TS-72XX SBC Watchdog"
+	depends on MACH_TS72XX
+	help
+	  Technologic Systems TS-7200, TS-7250 and TS-7260 boards have
+	  watchdog timer implemented in a external CPLD chip. Say Y here
+	  if you want to support for the watchdog timer on TS-72XX boards.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ts72xx_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 699199b..8e8a9b4 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
 obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
 obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
 obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
+obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
new file mode 100644
index 0000000..88b75b9
--- /dev/null
+++ b/drivers/watchdog/ts72xx_wdt.c
@@ -0,0 +1,458 @@
+/*
+ * Watchdog driver for Technologic Systems TS-72xx based SBCs
+ * (TS-7200, TS-7250 and TS-7260). These boards have external
+ * glue logic CPLD chip, which includes programmable watchdog
+ * timer.
+ *
+ * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
+ *
+ * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * 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/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)
+			  ")");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
+
+/**
+ * struct ts72xx_wdt - watchdog control structure
+ * @lock: lock that protects this structure
+ * @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		timeout;
+
+#define TS72XX_WDT_BUSY_FLAG		1
+#define TS72XX_WDT_EXPECT_CLOSE_FLAG	2
+	int		flags;
+
+	void __iomem	*control_reg;
+	void __iomem	*feed_reg;
+
+	struct platform_device *pdev;
+};
+
+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@all.
+ */
+static const struct {
+	int	timeout;
+	u8	ctrval;
+} ts72xx_wdt_map[] = {
+	{ 1, 3 },
+	{ 2, 5 },
+	{ 4, 6 },
+	{ 8, 7 },
+};
+
+/**
+ * normalize_timeout() - normalizes given timeout
+ * @new_timeout: timeout in seconds to be normalized
+ *
+ * This function normalizes given timeout value (in seconds)
+ * to value that is valid to TS-72xx watchdog timer. Valid
+ * values are 1, 2, 4 and 8 seconds. Timeout is rounded up
+ * to nearest valid timeout so for example value 3 yields
+ * 4 etc.
+ */
+static int normalize_timeout(int new_timeout)
+{
+	int i;
+
+	/* first limit it to 1 - 8 seconds */
+	if (new_timeout < 1)
+		new_timeout = 1;
+	else if (new_timeout > 8)
+		new_timeout = 8;
+
+	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
+		if (ts72xx_wdt_map[i].timeout >= new_timeout)
+			return ts72xx_wdt_map[i].timeout;
+	}
+
+	BUG();
+	/*NOTREACHED*/
+}
+
+/**
+ * timeout_to_ctrval() - converts given timeout to control register value
+ * @new_timeout: timeout in seconds to be converted (1, 2, 4 or 8)
+ *
+ * This function converts timeout in seconds to valid control register
+ * value. Note that @new_timeout must be normalized first with call to
+ * normalize_timeout().
+ */
+static u8 timeout_to_ctrval(int new_timeout)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
+		if (ts72xx_wdt_map[i].timeout == new_timeout)
+			return ts72xx_wdt_map[i].ctrval;
+	}
+
+	BUG();
+	/*NOTREACHED*/
+}
+
+/**
+ * ts72xx_wdt_kick() - kick the watchdog
+ * @wdt: watchdog to be kicked
+ *
+ * Called with @wdt->lock held.
+ */
+static 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(timeout_to_ctrval(wdt->timeout), 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);
+}
+
+static int ts72xx_wdt_open(struct inode *inode, struct file *file)
+{
+	struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
+
+	if (mutex_lock_interruptible(&wdt->lock))
+		return -ERESTARTSYS;
+
+	if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
+		mutex_unlock(&wdt->lock);
+		return -EBUSY;
+	}
+
+	wdt->flags = TS72XX_WDT_BUSY_FLAG;
+	wdt->timeout = normalize_timeout(timeout);
+	file->private_data = wdt;
+
+	ts72xx_wdt_start(wdt);
+
+	mutex_unlock(&wdt->lock);
+	return nonseekable_open(inode, file);
+}
+
+static int ts72xx_wdt_release(struct inode *inode, struct file *file)
+{
+	struct ts72xx_wdt *wdt = (struct ts72xx_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);
+	}
+
+	wdt->flags = 0;
+
+	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)
+{
+	struct ts72xx_wdt *wdt = (struct ts72xx_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;
+}
+
+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 = (struct ts72xx_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:
+		error = copy_to_user(argp, &winfo, sizeof(winfo));
+		break;
+
+	case WDIOC_KEEPALIVE:
+		ts72xx_wdt_kick(wdt);
+		break;
+
+	case WDIOC_SETOPTIONS: {
+		int options;
+
+		if (get_user(options, p)) {
+			error = -EFAULT;
+			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;
+		}
+
+		break;
+	}
+
+	case WDIOC_SETTIMEOUT: {
+		int new_timeout;
+
+		if (get_user(new_timeout, p)) {
+			error = -EFAULT;
+		} else {
+			ts72xx_wdt_stop(wdt);
+			wdt->timeout = normalize_timeout(new_timeout);
+			ts72xx_wdt_start(wdt);
+		}
+		/*FALLTHROUGH*/
+	}
+
+	case WDIOC_GETTIMEOUT:
+		if (put_user(wdt->timeout, p))
+			error = -EFAULT;
+		break;
+
+	default:
+		error = -ENOTTY;
+		break;
+	}
+
+	mutex_unlock(&wdt->lock);
+	return error;
+}
+
+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 struct miscdevice ts72xx_wdt_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &ts72xx_wdt_fops,
+};
+
+static __devinit int ts72xx_wdt_probe(struct platform_device *pdev)
+{
+	struct ts72xx_wdt *wdt;
+	struct resource *res;
+	int error = -EIO;
+
+	wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	mutex_init(&wdt->lock);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		goto fail;
+
+	wdt->control_reg = ioremap(res->start, resource_size(res));
+	if (!wdt->control_reg)
+		goto fail;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res)
+		goto fail;
+
+	wdt->feed_reg = ioremap(res->start, resource_size(res));
+	if (!wdt->feed_reg)
+		goto fail;
+
+	error = misc_register(&ts72xx_wdt_miscdev);
+	if (error)
+		goto fail;
+
+	platform_set_drvdata(pdev, wdt);
+	ts72xx_wdt_pdev = pdev;
+	wdt->pdev = pdev;
+
+	dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
+
+	return 0;
+
+fail:
+	platform_set_drvdata(pdev, NULL);
+
+	if (wdt->control_reg)
+		iounmap(wdt->control_reg);
+	if (wdt->feed_reg)
+		iounmap(wdt->feed_reg);
+
+	kfree(wdt);
+	return error;
+}
+
+static __devexit int ts72xx_wdt_remove(struct platform_device *pdev)
+{
+	struct ts72xx_wdt *wdt =
+		(struct ts72xx_wdt *)platform_get_drvdata(pdev);
+
+	if (wdt->control_reg)
+		iounmap(wdt->control_reg);
+	if (wdt->feed_reg)
+		iounmap(wdt->feed_reg);
+
+	kfree(wdt);
+
+	platform_set_drvdata(pdev, NULL);
+	return misc_deregister(&ts72xx_wdt_miscdev);
+}
+
+static struct platform_driver ts72xx_wdt_driver = {
+	.probe = ts72xx_wdt_probe,
+	.remove = __devexit_p(ts72xx_wdt_remove),
+	.driver = {
+		.name = "ts72xx-wdt",
+	},
+};
+
+static __init int ts72xx_wdt_init(void)
+{
+	return platform_driver_register(&ts72xx_wdt_driver);
+}
+module_init(ts72xx_wdt_init);
+
+static __exit void ts72xx_wdt_exit(void)
+{
+	platform_driver_unregister(&ts72xx_wdt_driver);
+}
+module_exit(ts72xx_wdt_exit);
+
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
+MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ts72xx-wdt");
-- 
1.5.6.5

[PATCH 2/2] ep93xx: added platform side support for TS-72xx WDT driver

[Mika Westerberg]

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
---
 arch/arm/mach-ep93xx/include/mach/ts72xx.h |    2 ++
 arch/arm/mach-ep93xx/ts72xx.c              |   21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-ep93xx/include/mach/ts72xx.h b/arch/arm/mach-ep93xx/include/mach/ts72xx.h
index 3bd934e..93107d8 100644
--- a/arch/arm/mach-ep93xx/include/mach/ts72xx.h
+++ b/arch/arm/mach-ep93xx/include/mach/ts72xx.h
@@ -65,6 +65,8 @@
 #define TS72XX_RTC_DATA_PHYS_BASE	0x11700000
 #define TS72XX_RTC_DATA_SIZE		0x00001000
 
+#define TS72XX_WDT_CONTROL_PHYS_BASE	0x23800000
+#define TS72XX_WDT_FEED_PHYS_BASE	0x23c00000
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/arm/mach-ep93xx/ts72xx.c b/arch/arm/mach-ep93xx/ts72xx.c
index 259f782..fac1ec7 100644
--- a/arch/arm/mach-ep93xx/ts72xx.c
+++ b/arch/arm/mach-ep93xx/ts72xx.c
@@ -166,6 +166,26 @@ static struct platform_device ts72xx_rtc_device = {
 	.num_resources	= 0,
 };
 
+static struct resource ts72xx_wdt_resources[] = {
+	{
+		.start	= TS72XX_WDT_CONTROL_PHYS_BASE,
+		.end	= TS72XX_WDT_CONTROL_PHYS_BASE + SZ_4K - 1,
+		.flags	= IORESOURCE_MEM,
+	},
+	{
+		.start	= TS72XX_WDT_FEED_PHYS_BASE,
+		.end	= TS72XX_WDT_FEED_PHYS_BASE + SZ_4K - 1,
+		.flags	= IORESOURCE_MEM,
+	},
+};
+
+static struct platform_device ts72xx_wdt_device = {
+	.name		= "ts72xx-wdt",
+	.id		= -1,
+	.num_resources 	= ARRAY_SIZE(ts72xx_wdt_resources),
+	.resource	= ts72xx_wdt_resources,
+};
+
 static struct ep93xx_eth_data ts72xx_eth_data = {
 	.phy_id		= 1,
 };
@@ -175,6 +195,7 @@ static void __init ts72xx_init_machine(void)
 	ep93xx_init_devices();
 	ts72xx_register_flash();
 	platform_device_register(&ts72xx_rtc_device);
+	platform_device_register(&ts72xx_wdt_device);
 
 	ep93xx_register_eth(&ts72xx_eth_data, 1);
 }
-- 
1.5.6.5

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Ryan Mallon]

Mika Westerberg wrote:
> Technologic Systems TS-72xx SBCs have external glue logic
> CPLD which includes watchdog timer. This driver implements
> kernel support for that.

Hi Mika, looks good. Some comments below.

> Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
> ---
>  drivers/watchdog/Kconfig      |   11 +
>  drivers/watchdog/Makefile     |    1 +
>  drivers/watchdog/ts72xx_wdt.c |  458 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 470 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/watchdog/ts72xx_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 3711b88..5204612 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -289,6 +289,17 @@ config ADX_WATCHDOG
>  	  Say Y here if you want support for the watchdog timer on Avionic
>  	  Design Xanthos boards.
>  
> +config TS72XX_WATCHDOG
> +	tristate "TS-72XX SBC Watchdog"
> +	depends on MACH_TS72XX
> +	help
> +	  Technologic Systems TS-7200, TS-7250 and TS-7260 boards have
> +	  watchdog timer implemented in a external CPLD chip. Say Y here
> +	  if you want to support for the watchdog timer on TS-72XX boards.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ts72xx_wdt.
> +
>  # AVR32 Architecture
>  
>  config AT32AP700X_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 699199b..8e8a9b4 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
>  obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
>  obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
>  obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
> +obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
>  
>  # AVR32 Architecture
>  obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
> new file mode 100644
> index 0000000..88b75b9
> --- /dev/null
> +++ b/drivers/watchdog/ts72xx_wdt.c
> @@ -0,0 +1,458 @@
> +/*
> + * Watchdog driver for Technologic Systems TS-72xx based SBCs
> + * (TS-7200, TS-7250 and TS-7260). These boards have external
> + * glue logic CPLD chip, which includes programmable watchdog
> + * timer.
> + *
> + * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
> + *
> + * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */

Nitpick: Space between top comment and first line of includes.

> +#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/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)
> +			  ")");
> +
> +static int nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, int, 0);
> +MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
> +
> +/**
> + * struct ts72xx_wdt - watchdog control structure
> + * @lock: lock that protects this structure
> + * @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		timeout;
> +
> +#define TS72XX_WDT_BUSY_FLAG		1
> +#define TS72XX_WDT_EXPECT_CLOSE_FLAG	2
> +	int		flags;
> +
> +	void __iomem	*control_reg;
> +	void __iomem	*feed_reg;
> +
> +	struct platform_device *pdev;
> +};
> +
> +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.
> + */
> +static const struct {
> +	int	timeout;
> +	u8	ctrval;
> +} ts72xx_wdt_map[] = {
> +	{ 1, 3 },
> +	{ 2, 5 },
> +	{ 4, 6 },
> +	{ 8, 7 },
> +};
> +
> +/**
> + * normalize_timeout() - normalizes given timeout
> + * @new_timeout: timeout in seconds to be normalized
> + *
> + * This function normalizes given timeout value (in seconds)
> + * to value that is valid to TS-72xx watchdog timer. Valid
> + * values are 1, 2, 4 and 8 seconds. Timeout is rounded up
> + * to nearest valid timeout so for example value 3 yields
> + * 4 etc.
> + */
> +static int normalize_timeout(int new_timeout)
> +{
> +	int i;
> +
> +	/* first limit it to 1 - 8 seconds */
> +	if (new_timeout < 1)
> +		new_timeout = 1;
> +	else if (new_timeout > 8)
> +		new_timeout = 8;

You can do:

	new_timeout = clamp_val(new_timeout, 1, 8);

for the same effect here.

> +
> +	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
> +		if (ts72xx_wdt_map[i].timeout >= new_timeout)
> +			return ts72xx_wdt_map[i].timeout;
> +	}
> +
> +	BUG();
> +	/*NOTREACHED*/

This is reached if !CONFIG_BUG, you should return -EINVAL, and handle it
gracefully in the caller.

> +}
> +
> +/**
> + * timeout_to_ctrval() - converts given timeout to control register value
> + * @new_timeout: timeout in seconds to be converted (1, 2, 4 or 8)
> + *
> + * This function converts timeout in seconds to valid control register
> + * value. Note that @new_timeout must be normalized first with call to
> + * normalize_timeout().
> + */

If you must call normalize timeout first, the can the two functions be
combined so that you only need to do the loop once?

> +static u8 timeout_to_ctrval(int new_timeout)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
> +		if (ts72xx_wdt_map[i].timeout == new_timeout)
> +			return ts72xx_wdt_map[i].ctrval;
> +	}
> +
> +	BUG();
> +	/*NOTREACHED*/

Same as above, should return -EINVAL

> +}
> +
> +/**
> + * ts72xx_wdt_kick() - kick the watchdog
> + * @wdt: watchdog to be kicked
> + *
> + * Called with @wdt->lock held.
> + */
> +static void ts72xx_wdt_kick(struct ts72xx_wdt *wdt)

Should probably be marked inline.

> +{
> +	__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(timeout_to_ctrval(wdt->timeout), 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);
> +}
> +
> +static int ts72xx_wdt_open(struct inode *inode, struct file *file)
> +{
> +	struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
> +
> +	if (mutex_lock_interruptible(&wdt->lock))
> +		return -ERESTARTSYS;
> +
> +	if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
> +		mutex_unlock(&wdt->lock);
> +		return -EBUSY;
> +	}
> +
> +	wdt->flags = TS72XX_WDT_BUSY_FLAG;
> +	wdt->timeout = normalize_timeout(timeout);
> +	file->private_data = wdt;
> +
> +	ts72xx_wdt_start(wdt);
> +
> +	mutex_unlock(&wdt->lock);
> +	return nonseekable_open(inode, file);
> +}
> +
> +static int ts72xx_wdt_release(struct inode *inode, struct file *file)
> +{
> +	struct ts72xx_wdt *wdt = (struct ts72xx_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);
> +	}
> +
> +	wdt->flags = 0;
> +
> +	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)
> +{
> +	struct ts72xx_wdt *wdt = (struct ts72xx_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;
> +}
> +
> +static const struct watchdog_info winfo = {
> +	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
> +	.firmware_version = 1,
> +	.identity = "TS-72XX WDT",
> +};

Nitpick: Tab align struct assignments.

> +
> +static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
> +			     unsigned long arg)
> +{
> +	struct ts72xx_wdt *wdt = (struct ts72xx_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:
> +		error = copy_to_user(argp, &winfo, sizeof(winfo));
> +		break;
> +
> +	case WDIOC_KEEPALIVE:
> +		ts72xx_wdt_kick(wdt);
> +		break;
> +
> +	case WDIOC_SETOPTIONS: {
> +		int options;
> +
> +		if (get_user(options, p)) {
> +			error = -EFAULT;
> +			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;
> +		}
> +
> +		break;
> +	}
> +
> +	case WDIOC_SETTIMEOUT: {
> +		int new_timeout;
> +
> +		if (get_user(new_timeout, p)) {
> +			error = -EFAULT;
> +		} else {
> +			ts72xx_wdt_stop(wdt);
> +			wdt->timeout = normalize_timeout(new_timeout);
> +			ts72xx_wdt_start(wdt);
> +		}
> +		/*FALLTHROUGH*/
> +	}
> +
> +	case WDIOC_GETTIMEOUT:
> +		if (put_user(wdt->timeout, p))
> +			error = -EFAULT;
> +		break;
> +
> +	default:
> +		error = -ENOTTY;
> +		break;
> +	}
> +
> +	mutex_unlock(&wdt->lock);
> +	return error;
> +}
> +
> +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 struct miscdevice ts72xx_wdt_miscdev = {
> +	.minor		= WATCHDOG_MINOR,
> +	.name		= "watchdog",
> +	.fops		= &ts72xx_wdt_fops,
> +};
> +
> +static __devinit int ts72xx_wdt_probe(struct platform_device *pdev)
> +{
> +	struct ts72xx_wdt *wdt;
> +	struct resource *res;
> +	int error = -EIO;
> +
> +	wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);

	sizeof(struct ts72xx_wdt)

is the preferred style I think. If the other watchdog drivers do it this
way just leave it though.

> +	if (!wdt)
> +		return -ENOMEM;
> +
> +	mutex_init(&wdt->lock);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		goto fail;
> +
> +	wdt->control_reg = ioremap(res->start, resource_size(res));
> +	if (!wdt->control_reg)
> +		goto fail;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	if (!res)
> +		goto fail;
> +
> +	wdt->feed_reg = ioremap(res->start, resource_size(res));
> +	if (!wdt->feed_reg)
> +		goto fail;
> +
> +	error = misc_register(&ts72xx_wdt_miscdev);
> +	if (error)
> +		goto fail;
> +
> +	platform_set_drvdata(pdev, wdt);
> +	ts72xx_wdt_pdev = pdev;
> +	wdt->pdev = pdev;
> +
> +	dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
> +
> +	return 0;
> +
> +fail:
> +	platform_set_drvdata(pdev, NULL);

I don't think you need this in the error path since platform_set_drvdata
is called after the last goto fail.

> +	if (wdt->control_reg)
> +		iounmap(wdt->control_reg);
> +	if (wdt->feed_reg)
> +		iounmap(wdt->feed_reg);
> +
> +	kfree(wdt);
> +	return error;
> +}
> +
> +static __devexit int ts72xx_wdt_remove(struct platform_device *pdev)
> +{
> +	struct ts72xx_wdt *wdt =
> +		(struct ts72xx_wdt *)platform_get_drvdata(pdev);
> +
> +	if (wdt->control_reg)
> +		iounmap(wdt->control_reg);
> +	if (wdt->feed_reg)
> +		iounmap(wdt->feed_reg);
> +
> +	kfree(wdt);
> +
> +	platform_set_drvdata(pdev, NULL);
> +	return misc_deregister(&ts72xx_wdt_miscdev);
> +}
> +
> +static struct platform_driver ts72xx_wdt_driver = {
> +	.probe = ts72xx_wdt_probe,
> +	.remove = __devexit_p(ts72xx_wdt_remove),
> +	.driver = {
> +		.name = "ts72xx-wdt",
> +	},
> +};
> +
> +static __init int ts72xx_wdt_init(void)
> +{
> +	return platform_driver_register(&ts72xx_wdt_driver);
> +}
> +module_init(ts72xx_wdt_init);
> +
> +static __exit void ts72xx_wdt_exit(void)
> +{
> +	platform_driver_unregister(&ts72xx_wdt_driver);
> +}
> +module_exit(ts72xx_wdt_exit);
> +
> +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
> +MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:ts72xx-wdt");


-- 
Bluewater Systems Ltd - ARM Technology Solution Centre

Ryan Mallon         		5 Amuri Park, 404 Barbadoes St
ryan at bluewatersys.com         	PO Box 13 889, Christchurch 8013
http://www.bluewatersys.com	New Zealand
Phone: +64 3 3779127		Freecall: Australia 1800 148 751
Fax:   +64 3 3779135			  USA 1800 261 2934

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Mika Westerberg]

Hi Ryan,

On Fri, Dec 04, 2009 at 09:07:10AM +1300, Ryan Mallon wrote:
> Mika Westerberg wrote:
> > Technologic Systems TS-72xx SBCs have external glue logic
> > CPLD which includes watchdog timer. This driver implements
> > kernel support for that.
> 
> Hi Mika, looks good. Some comments below.

Thank you very much for your comments. My answers to the comments are
below.

I'll wait a bit if someone else still has comments and then prepare
version 2 of the patches.

Thanks,
MW

> 
> > Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
> > ---
> >  drivers/watchdog/Kconfig      |   11 +
> >  drivers/watchdog/Makefile     |    1 +
> >  drivers/watchdog/ts72xx_wdt.c |  458 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 470 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/watchdog/ts72xx_wdt.c
> > 
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 3711b88..5204612 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -289,6 +289,17 @@ config ADX_WATCHDOG
> >  	  Say Y here if you want support for the watchdog timer on Avionic
> >  	  Design Xanthos boards.
> >  
> > +config TS72XX_WATCHDOG
> > +	tristate "TS-72XX SBC Watchdog"
> > +	depends on MACH_TS72XX
> > +	help
> > +	  Technologic Systems TS-7200, TS-7250 and TS-7260 boards have
> > +	  watchdog timer implemented in a external CPLD chip. Say Y here
> > +	  if you want to support for the watchdog timer on TS-72XX boards.
> > +
> > +	  To compile this driver as a module, choose M here: the
> > +	  module will be called ts72xx_wdt.
> > +
> >  # AVR32 Architecture
> >  
> >  config AT32AP700X_WDT
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index 699199b..8e8a9b4 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -46,6 +46,7 @@ obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
> >  obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
> >  obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
> >  obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
> > +obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
> >  
> >  # AVR32 Architecture
> >  obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> > diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
> > new file mode 100644
> > index 0000000..88b75b9
> > --- /dev/null
> > +++ b/drivers/watchdog/ts72xx_wdt.c
> > @@ -0,0 +1,458 @@
> > +/*
> > + * Watchdog driver for Technologic Systems TS-72xx based SBCs
> > + * (TS-7200, TS-7250 and TS-7260). These boards have external
> > + * glue logic CPLD chip, which includes programmable watchdog
> > + * timer.
> > + *
> > + * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
> > + *
> > + * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
> > + *
> > + * This file is licensed under the terms of the GNU General Public
> > + * License version 2. This program is licensed "as is" without any
> > + * warranty of any kind, whether express or implied.
> > + */
> 
> Nitpick: Space between top comment and first line of includes.

Will fix to v2.

> 
> > +#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/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)
> > +			  ")");
> > +
> > +static int nowayout = WATCHDOG_NOWAYOUT;
> > +module_param(nowayout, int, 0);
> > +MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
> > +
> > +/**
> > + * struct ts72xx_wdt - watchdog control structure
> > + * @lock: lock that protects this structure
> > + * @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		timeout;
> > +
> > +#define TS72XX_WDT_BUSY_FLAG		1
> > +#define TS72XX_WDT_EXPECT_CLOSE_FLAG	2
> > +	int		flags;
> > +
> > +	void __iomem	*control_reg;
> > +	void __iomem	*feed_reg;
> > +
> > +	struct platform_device *pdev;
> > +};
> > +
> > +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.
> > + */
> > +static const struct {
> > +	int	timeout;
> > +	u8	ctrval;
> > +} ts72xx_wdt_map[] = {
> > +	{ 1, 3 },
> > +	{ 2, 5 },
> > +	{ 4, 6 },
> > +	{ 8, 7 },
> > +};
> > +
> > +/**
> > + * normalize_timeout() - normalizes given timeout
> > + * @new_timeout: timeout in seconds to be normalized
> > + *
> > + * This function normalizes given timeout value (in seconds)
> > + * to value that is valid to TS-72xx watchdog timer. Valid
> > + * values are 1, 2, 4 and 8 seconds. Timeout is rounded up
> > + * to nearest valid timeout so for example value 3 yields
> > + * 4 etc.
> > + */
> > +static int normalize_timeout(int new_timeout)
> > +{
> > +	int i;
> > +
> > +	/* first limit it to 1 - 8 seconds */
> > +	if (new_timeout < 1)
> > +		new_timeout = 1;
> > +	else if (new_timeout > 8)
> > +		new_timeout = 8;
> 
> You can do:
> 
> 	new_timeout = clamp_val(new_timeout, 1, 8);
> 
> for the same effect here.

Wow, I didn't even know that such functions (macros) exists
in kernel :) I will fix this in v2.

> 
> > +
> > +	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
> > +		if (ts72xx_wdt_map[i].timeout >= new_timeout)
> > +			return ts72xx_wdt_map[i].timeout;
> > +	}
> > +
> > +	BUG();
> > +	/*NOTREACHED*/
> 
> This is reached if !CONFIG_BUG, you should return -EINVAL, and handle it
> gracefully in the caller.

OK. Will be fixed in v2.

> 
> > +}
> > +
> > +/**
> > + * timeout_to_ctrval() - converts given timeout to control register value
> > + * @new_timeout: timeout in seconds to be converted (1, 2, 4 or 8)
> > + *
> > + * This function converts timeout in seconds to valid control register
> > + * value. Note that @new_timeout must be normalized first with call to
> > + * normalize_timeout().
> > + */
> 
> If you must call normalize timeout first, the can the two functions be
> combined so that you only need to do the loop once?

Yeah, that's probably better way. I'll try to combine them
in v2.

> 
> > +static u8 timeout_to_ctrval(int new_timeout)
> > +{
> > +	int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
> > +		if (ts72xx_wdt_map[i].timeout == new_timeout)
> > +			return ts72xx_wdt_map[i].ctrval;
> > +	}
> > +
> > +	BUG();
> > +	/*NOTREACHED*/
> 
> Same as above, should return -EINVAL

Will fix in v2.

> 
> > +}
> > +
> > +/**
> > + * ts72xx_wdt_kick() - kick the watchdog
> > + * @wdt: watchdog to be kicked
> > + *
> > + * Called with @wdt->lock held.
> > + */
> > +static void ts72xx_wdt_kick(struct ts72xx_wdt *wdt)
> 
> Should probably be marked inline.

Ok. Will do.

> 
> > +{
> > +	__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(timeout_to_ctrval(wdt->timeout), 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);
> > +}
> > +
> > +static int ts72xx_wdt_open(struct inode *inode, struct file *file)
> > +{
> > +	struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
> > +
> > +	if (mutex_lock_interruptible(&wdt->lock))
> > +		return -ERESTARTSYS;
> > +
> > +	if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
> > +		mutex_unlock(&wdt->lock);
> > +		return -EBUSY;
> > +	}
> > +
> > +	wdt->flags = TS72XX_WDT_BUSY_FLAG;
> > +	wdt->timeout = normalize_timeout(timeout);
> > +	file->private_data = wdt;
> > +
> > +	ts72xx_wdt_start(wdt);
> > +
> > +	mutex_unlock(&wdt->lock);
> > +	return nonseekable_open(inode, file);
> > +}
> > +
> > +static int ts72xx_wdt_release(struct inode *inode, struct file *file)
> > +{
> > +	struct ts72xx_wdt *wdt = (struct ts72xx_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);
> > +	}
> > +
> > +	wdt->flags = 0;
> > +
> > +	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)
> > +{
> > +	struct ts72xx_wdt *wdt = (struct ts72xx_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;
> > +}
> > +
> > +static const struct watchdog_info winfo = {
> > +	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
> > +	.firmware_version = 1,
> > +	.identity = "TS-72XX WDT",
> > +};
> 
> Nitpick: Tab align struct assignments.

Ok. Will fix in v2.

> 
> > +
> > +static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
> > +			     unsigned long arg)
> > +{
> > +	struct ts72xx_wdt *wdt = (struct ts72xx_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:
> > +		error = copy_to_user(argp, &winfo, sizeof(winfo));
> > +		break;
> > +
> > +	case WDIOC_KEEPALIVE:
> > +		ts72xx_wdt_kick(wdt);
> > +		break;
> > +
> > +	case WDIOC_SETOPTIONS: {
> > +		int options;
> > +
> > +		if (get_user(options, p)) {
> > +			error = -EFAULT;
> > +			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;
> > +		}
> > +
> > +		break;
> > +	}
> > +
> > +	case WDIOC_SETTIMEOUT: {
> > +		int new_timeout;
> > +
> > +		if (get_user(new_timeout, p)) {
> > +			error = -EFAULT;
> > +		} else {
> > +			ts72xx_wdt_stop(wdt);
> > +			wdt->timeout = normalize_timeout(new_timeout);
> > +			ts72xx_wdt_start(wdt);
> > +		}
> > +		/*FALLTHROUGH*/
> > +	}
> > +
> > +	case WDIOC_GETTIMEOUT:
> > +		if (put_user(wdt->timeout, p))
> > +			error = -EFAULT;
> > +		break;
> > +
> > +	default:
> > +		error = -ENOTTY;
> > +		break;
> > +	}
> > +
> > +	mutex_unlock(&wdt->lock);
> > +	return error;
> > +}
> > +
> > +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 struct miscdevice ts72xx_wdt_miscdev = {
> > +	.minor		= WATCHDOG_MINOR,
> > +	.name		= "watchdog",
> > +	.fops		= &ts72xx_wdt_fops,
> > +};
> > +
> > +static __devinit int ts72xx_wdt_probe(struct platform_device *pdev)
> > +{
> > +	struct ts72xx_wdt *wdt;
> > +	struct resource *res;
> > +	int error = -EIO;
> > +
> > +	wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
> 
> 	sizeof(struct ts72xx_wdt)
> 
> is the preferred style I think. If the other watchdog drivers do it this
> way just leave it though.

It seems that both styles are used in watchdog drivers. I'll change
this to the preferred style in v2.

> 
> > +	if (!wdt)
> > +		return -ENOMEM;
> > +
> > +	mutex_init(&wdt->lock);
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	if (!res)
> > +		goto fail;
> > +
> > +	wdt->control_reg = ioremap(res->start, resource_size(res));
> > +	if (!wdt->control_reg)
> > +		goto fail;
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> > +	if (!res)
> > +		goto fail;
> > +
> > +	wdt->feed_reg = ioremap(res->start, resource_size(res));
> > +	if (!wdt->feed_reg)
> > +		goto fail;
> > +
> > +	error = misc_register(&ts72xx_wdt_miscdev);
> > +	if (error)
> > +		goto fail;
> > +
> > +	platform_set_drvdata(pdev, wdt);
> > +	ts72xx_wdt_pdev = pdev;
> > +	wdt->pdev = pdev;
> > +
> > +	dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
> > +
> > +	return 0;
> > +
> > +fail:
> > +	platform_set_drvdata(pdev, NULL);
> 
> I don't think you need this in the error path since platform_set_drvdata
> is called after the last goto fail.

Ah, good catch. Will fix in v2.

> 
> > +	if (wdt->control_reg)
> > +		iounmap(wdt->control_reg);
> > +	if (wdt->feed_reg)
> > +		iounmap(wdt->feed_reg);
> > +
> > +	kfree(wdt);
> > +	return error;
> > +}
> > +
> > +static __devexit int ts72xx_wdt_remove(struct platform_device *pdev)
> > +{
> > +	struct ts72xx_wdt *wdt =
> > +		(struct ts72xx_wdt *)platform_get_drvdata(pdev);
> > +
> > +	if (wdt->control_reg)
> > +		iounmap(wdt->control_reg);
> > +	if (wdt->feed_reg)
> > +		iounmap(wdt->feed_reg);
> > +
> > +	kfree(wdt);
> > +
> > +	platform_set_drvdata(pdev, NULL);
> > +	return misc_deregister(&ts72xx_wdt_miscdev);
> > +}
> > +
> > +static struct platform_driver ts72xx_wdt_driver = {
> > +	.probe = ts72xx_wdt_probe,
> > +	.remove = __devexit_p(ts72xx_wdt_remove),
> > +	.driver = {
> > +		.name = "ts72xx-wdt",
> > +	},
> > +};
> > +
> > +static __init int ts72xx_wdt_init(void)
> > +{
> > +	return platform_driver_register(&ts72xx_wdt_driver);
> > +}
> > +module_init(ts72xx_wdt_init);
> > +
> > +static __exit void ts72xx_wdt_exit(void)
> > +{
> > +	platform_driver_unregister(&ts72xx_wdt_driver);
> > +}
> > +module_exit(ts72xx_wdt_exit);
> > +
> > +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
> > +MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
> > +MODULE_LICENSE("GPL");
> > +MODULE_ALIAS("platform:ts72xx-wdt");
> 
> 
> -- 
> Bluewater Systems Ltd - ARM Technology Solution Centre
> 
> Ryan Mallon         		5 Amuri Park, 404 Barbadoes St
> ryan at bluewatersys.com         	PO Box 13 889, Christchurch 8013
> http://www.bluewatersys.com	New Zealand
> Phone: +64 3 3779127		Freecall: Australia 1800 148 751
> Fax:   +64 3 3779135			  USA 1800 261 2934

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Alexander Clouter]

Mika Westerberg <mika.westerberg@iki.fi> wrote:
>
> Technologic Systems TS-72xx SBCs have external glue logic
> CPLD which includes watchdog timer. This driver implements
> kernel support for that.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
> ---
> drivers/watchdog/Kconfig      |   11 +
> drivers/watchdog/Makefile     |    1 +
> drivers/watchdog/ts72xx_wdt.c |  458 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 470 insertions(+), 0 deletions(-)
> create mode 100644 drivers/watchdog/ts72xx_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 3711b88..5204612 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -289,6 +289,17 @@ config ADX_WATCHDOG
>          Say Y here if you want support for the watchdog timer on Avionic
>          Design Xanthos boards.
> 
> +config TS72XX_WATCHDOG
> +       tristate "TS-72XX SBC Watchdog"
> +       depends on MACH_TS72XX
> +       help
> +         Technologic Systems TS-7200, TS-7250 and TS-7260 boards have
> +         watchdog timer implemented in a external CPLD chip. Say Y here
> +         if you want to support for the watchdog timer on TS-72XX boards.
> +
> +         To compile this driver as a module, choose M here: the
> +         module will be called ts72xx_wdt.
> +
> # AVR32 Architecture
>
....and also on the TS-78XX boards.  Although my TS-7800 board is being 
neglected at the moment it would be great if you could replace 
everywhere you put ts72xx with ts7xxx and such.  Means when I add the 
platform hooks for the TS-78xx I do not have to submit a patch that is a 
rather intrusive rename/relabelling one.

Cheers

-- 
Alexander Clouter
.sigmonster says: Monday is an awful way to spend one seventh of your life.

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Mika Westerberg]

On Fri, Dec 04, 2009 at 10:28:21AM +0000, Alexander Clouter wrote:

> ....and also on the TS-78XX boards.  Although my TS-7800 board is being 
> neglected at the moment it would be great if you could replace 
> everywhere you put ts72xx with ts7xxx and such.  Means when I add the 
> platform hooks for the TS-78xx I do not have to submit a patch that is a 
> rather intrusive rename/relabelling one.

Hi,

Is the TS-7800 watchdog timer similar than the ones in TS-72xx SBCs? I couldn't
find any documentation about that in TS web site. If this is the case then
I would be more than happy to do this stuff.

Thanks,
MW

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Alexander Clouter]

Hi,

* Mika Westerberg <mika.westerberg@iki.fi> [2009-12-04 13:33:58+0200]:
>
> On Fri, Dec 04, 2009 at 10:28:21AM +0000, Alexander Clouter wrote:
> 
> > ....and also on the TS-78XX boards.  Although my TS-7800 board is being 
> > neglected at the moment it would be great if you could replace 
> > everywhere you put ts72xx with ts7xxx and such.  Means when I add the 
> > platform hooks for the TS-78xx I do not have to submit a patch that is a 
> > rather intrusive rename/relabelling one.
> 
> Is the TS-7800 watchdog timer similar than the ones in TS-72xx SBCs? I couldn't
> find any documentation about that in TS web site. If this is the case then
> I would be more than happy to do this stuff.
> 
TS made the FPGA/AVR code/hardware more or less identical to retain 
backwards compatibility.  Obviously the platform specific resource maps 
might be a little different but that is all.  The NAND, for example, is 
also identical on both, the TS-7800 however adds a hardware ECC and 
option to allow DMA transfers.

The details are only really documented in the source code of a tool TS 
provide:

http://svn.lee.org/swarm/trunk/spu/src/dillo7800/root/ts7800ctl.c

Cheers

-- 
Alexander Clouter
.sigmonster says: Now I understand the meaning of "THE MOD SQUAD"!

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Alexander Clouter]

Hi,

* Alexander Clouter <alex@digriz.org.uk> [2009-12-04 11:45:07+0000]:
>
> * Mika Westerberg <mika.westerberg@iki.fi> [2009-12-04 13:33:58+0200]:
> >
> > On Fri, Dec 04, 2009 at 10:28:21AM +0000, Alexander Clouter wrote:
> > 
> > > ....and also on the TS-78XX boards.  Although my TS-7800 board is being 
> > > neglected at the moment it would be great if you could replace 
> > > everywhere you put ts72xx with ts7xxx and such.  Means when I add the 
> > > platform hooks for the TS-78xx I do not have to submit a patch that is a 
> > > rather intrusive rename/relabelling one.
> > 
> > Is the TS-7800 watchdog timer similar than the ones in TS-72xx SBCs? I couldn't
> > find any documentation about that in TS web site. If this is the case then
> > I would be more than happy to do this stuff.
> > 
> TS made the FPGA/AVR code/hardware more or less identical to retain 
> backwards compatibility.  Obviously the platform specific resource maps 
> might be a little different but that is all.  The NAND, for example, is 
> also identical on both, the TS-7800 however adds a hardware ECC and 
> option to allow DMA transfers.
> 
> The details are only really documented in the source code of a tool TS 
> provide:
> 
> http://svn.lee.org/swarm/trunk/spu/src/dillo7800/root/ts7800ctl.c
> 
Hmmmm, on closer reinspection, the AVR hides behind an I2C bus so 
probably worth forgetting the renaming suggestion.

Cheers

-- 
Alexander Clouter
.sigmonster says: There Is No Cabal.

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[Mika Westerberg]

On Fri, Dec 04, 2009 at 11:49:50AM +0000, Alexander Clouter wrote:
> Hi,
> 
> * Alexander Clouter <alex@digriz.org.uk> [2009-12-04 11:45:07+0000]:
> >
> > * Mika Westerberg <mika.westerberg@iki.fi> [2009-12-04 13:33:58+0200]:
> > >
> > > On Fri, Dec 04, 2009 at 10:28:21AM +0000, Alexander Clouter wrote:
> > > 
> > > > ....and also on the TS-78XX boards.  Although my TS-7800 board is being 
> > > > neglected at the moment it would be great if you could replace 
> > > > everywhere you put ts72xx with ts7xxx and such.  Means when I add the 
> > > > platform hooks for the TS-78xx I do not have to submit a patch that is a 
> > > > rather intrusive rename/relabelling one.
> > > 
> > > Is the TS-7800 watchdog timer similar than the ones in TS-72xx SBCs? I couldn't
> > > find any documentation about that in TS web site. If this is the case then
> > > I would be more than happy to do this stuff.
> > > 
> > TS made the FPGA/AVR code/hardware more or less identical to retain 
> > backwards compatibility.  Obviously the platform specific resource maps 
> > might be a little different but that is all.  The NAND, for example, is 
> > also identical on both, the TS-7800 however adds a hardware ECC and 
> > option to allow DMA transfers.
> > 
> > The details are only really documented in the source code of a tool TS 
> > provide:
> > 
> > http://svn.lee.org/swarm/trunk/spu/src/dillo7800/root/ts7800ctl.c
> > 
> Hmmmm, on closer reinspection, the AVR hides behind an I2C bus so 
> probably worth forgetting the renaming suggestion.

OK. Thanks for the information. I'll keep it as ts72xx for now.

MW

[PATCH 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

[H Hartley Sweeten]

On Thursday, December 03, 2009 12:35 PM, Mika Westerberg wrote:
> Technologic Systems TS-72xx SBCs have external glue logic
> CPLD which includes watchdog timer. This driver implements
> kernel support for that.

Hello Mika,

A couple comments in addition to the ones Ryan already mentioned.

> 
> Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
> ---
>  drivers/watchdog/Kconfig      |   11 +
>  drivers/watchdog/Makefile     |    1 +
>  drivers/watchdog/ts72xx_wdt.c |  458 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 470 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/watchdog/ts72xx_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 3711b88..5204612 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -289,6 +289,17 @@ config ADX_WATCHDOG
>  	  Say Y here if you want support for the watchdog timer on Avionic
>  	  Design Xanthos boards.
>  
> +config TS72XX_WATCHDOG
> +	tristate "TS-72XX SBC Watchdog"
> +	depends on MACH_TS72XX
> +	help
> +	  Technologic Systems TS-7200, TS-7250 and TS-7260 boards have
> +	  watchdog timer implemented in a external CPLD chip. Say Y here
> +	  if you want to support for the watchdog timer on TS-72XX boards.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ts72xx_wdt.
> +
>  # AVR32 Architecture
>  
>  config AT32AP700X_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 699199b..8e8a9b4 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
>  obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
>  obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
>  obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
> +obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
>  
>  # AVR32 Architecture
>  obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
> new file mode 100644
> index 0000000..88b75b9
> --- /dev/null
> +++ b/drivers/watchdog/ts72xx_wdt.c
> @@ -0,0 +1,458 @@
> +/*
> + * Watchdog driver for Technologic Systems TS-72xx based SBCs
> + * (TS-7200, TS-7250 and TS-7260). These boards have external
> + * glue logic CPLD chip, which includes programmable watchdog
> + * timer.
> + *
> + * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
> + *
> + * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * 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/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)
> +			  ")");
> +
> +static int nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, int, 0);
> +MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
> +
> +/**
> + * struct ts72xx_wdt - watchdog control structure
> + * @lock: lock that protects this structure
> + * @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		timeout;
> +
> +#define TS72XX_WDT_BUSY_FLAG		1
> +#define TS72XX_WDT_EXPECT_CLOSE_FLAG	2
> +	int		flags;
> +
> +	void __iomem	*control_reg;
> +	void __iomem	*feed_reg;
> +
> +	struct platform_device *pdev;
> +};
> +
> +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.
> + */
> +static const struct {
> +	int	timeout;
> +	u8	ctrval;
> +} ts72xx_wdt_map[] = {
> +	{ 1, 3 },
> +	{ 2, 5 },
> +	{ 4, 6 },
> +	{ 8, 7 },
> +};
> +
> +/**
> + * normalize_timeout() - normalizes given timeout
> + * @new_timeout: timeout in seconds to be normalized
> + *
> + * This function normalizes given timeout value (in seconds)
> + * to value that is valid to TS-72xx watchdog timer. Valid
> + * values are 1, 2, 4 and 8 seconds. Timeout is rounded up
> + * to nearest valid timeout so for example value 3 yields
> + * 4 etc.
> + */
> +static int normalize_timeout(int new_timeout)
> +{
> +	int i;
> +
> +	/* first limit it to 1 - 8 seconds */
> +	if (new_timeout < 1)
> +		new_timeout = 1;
> +	else if (new_timeout > 8)
> +		new_timeout = 8;
> +
> +	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
> +		if (ts72xx_wdt_map[i].timeout >= new_timeout)
> +			return ts72xx_wdt_map[i].timeout;
> +	}
> +
> +	BUG();
> +	/*NOTREACHED*/
> +}
> +
> +/**
> + * timeout_to_ctrval() - converts given timeout to control register value
> + * @new_timeout: timeout in seconds to be converted (1, 2, 4 or 8)
> + *
> + * This function converts timeout in seconds to valid control register
> + * value. Note that @new_timeout must be normalized first with call to
> + * normalize_timeout().
> + */
> +static u8 timeout_to_ctrval(int new_timeout)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
> +		if (ts72xx_wdt_map[i].timeout == new_timeout)
> +			return ts72xx_wdt_map[i].ctrval;
> +	}
> +
> +	BUG();
> +	/*NOTREACHED*/
> +}
> +
> +/**
> + * ts72xx_wdt_kick() - kick the watchdog
> + * @wdt: watchdog to be kicked
> + *
> + * Called with @wdt->lock held.
> + */
> +static 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(timeout_to_ctrval(wdt->timeout), 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);
> +}
> +
> +static int ts72xx_wdt_open(struct inode *inode, struct file *file)
> +{
> +	struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
> +
> +	if (mutex_lock_interruptible(&wdt->lock))
> +		return -ERESTARTSYS;
> +
> +	if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
> +		mutex_unlock(&wdt->lock);
> +		return -EBUSY;
> +	}
> +
> +	wdt->flags = TS72XX_WDT_BUSY_FLAG;
> +	wdt->timeout = normalize_timeout(timeout);
> +	file->private_data = wdt;
> +
> +	ts72xx_wdt_start(wdt);
> +
> +	mutex_unlock(&wdt->lock);
> +	return nonseekable_open(inode, file);
> +}
> +
> +static int ts72xx_wdt_release(struct inode *inode, struct file *file)
> +{
> +	struct ts72xx_wdt *wdt = (struct ts72xx_wdt *)file->private_data;

The cast is not needed, file->private_data is a void *.

> +
> +	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);
> +	}
> +
> +	wdt->flags = 0;
> +
> +	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)
> +{
> +	struct ts72xx_wdt *wdt = (struct ts72xx_wdt *)file->private_data;

Same here.

> +
> +	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;
> +}
> +
> +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 = (struct ts72xx_wdt *)file->private_data;

And here.

> +	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:
> +		error = copy_to_user(argp, &winfo, sizeof(winfo));
> +		break;
> +
> +	case WDIOC_KEEPALIVE:
> +		ts72xx_wdt_kick(wdt);
> +		break;
> +
> +	case WDIOC_SETOPTIONS: {
> +		int options;
> +
> +		if (get_user(options, p)) {
> +			error = -EFAULT;
> +			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;
> +		}
> +
> +		break;
> +	}
> +
> +	case WDIOC_SETTIMEOUT: {
> +		int new_timeout;
> +
> +		if (get_user(new_timeout, p)) {
> +			error = -EFAULT;
> +		} else {
> +			ts72xx_wdt_stop(wdt);
> +			wdt->timeout = normalize_timeout(new_timeout);
> +			ts72xx_wdt_start(wdt);
> +		}
> +		/*FALLTHROUGH*/
> +	}
> +
> +	case WDIOC_GETTIMEOUT:
> +		if (put_user(wdt->timeout, p))
> +			error = -EFAULT;
> +		break;
> +
> +	default:
> +		error = -ENOTTY;
> +		break;
> +	}
> +
> +	mutex_unlock(&wdt->lock);
> +	return error;
> +}
> +
> +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 struct miscdevice ts72xx_wdt_miscdev = {
> +	.minor		= WATCHDOG_MINOR,
> +	.name		= "watchdog",
> +	.fops		= &ts72xx_wdt_fops,
> +};
> +
> +static __devinit int ts72xx_wdt_probe(struct platform_device *pdev)
> +{
> +	struct ts72xx_wdt *wdt;
> +	struct resource *res;
> +	int error = -EIO;
> +
> +	wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
> +	if (!wdt)
> +		return -ENOMEM;
> +
> +	mutex_init(&wdt->lock);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		goto fail;
> +
> +	wdt->control_reg = ioremap(res->start, resource_size(res));
> +	if (!wdt->control_reg)
> +		goto fail;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	if (!res)
> +		goto fail;
> +
> +	wdt->feed_reg = ioremap(res->start, resource_size(res));
> +	if (!wdt->feed_reg)
> +		goto fail;
> +

Please add a request_mem_region() before doing the ioremap()'s.

> +	error = misc_register(&ts72xx_wdt_miscdev);
> +	if (error)
> +		goto fail;
> +
> +	platform_set_drvdata(pdev, wdt);
> +	ts72xx_wdt_pdev = pdev;
> +	wdt->pdev = pdev;
> +
> +	dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
> +
> +	return 0;
> +
> +fail:
> +	platform_set_drvdata(pdev, NULL);
> +
> +	if (wdt->control_reg)
> +		iounmap(wdt->control_reg);
> +	if (wdt->feed_reg)
> +		iounmap(wdt->feed_reg);

Also, add a release_mem_region() after each iounmap().

> +
> +	kfree(wdt);
> +	return error;
> +}
> +
> +static __devexit int ts72xx_wdt_remove(struct platform_device *pdev)
> +{
> +	struct ts72xx_wdt *wdt =
> +		(struct ts72xx_wdt *)platform_get_drvdata(pdev);

Unnecessary cast.

> +
> +	if (wdt->control_reg)
> +		iounmap(wdt->control_reg);
> +	if (wdt->feed_reg)
> +		iounmap(wdt->feed_reg);

release_mem_region() here also.

> +
> +	kfree(wdt);
> +
> +	platform_set_drvdata(pdev, NULL);
> +	return misc_deregister(&ts72xx_wdt_miscdev);

The misc_deregister() needs to happen before the kfree() to prevent
any race conditions.

> +}
> +
> +static struct platform_driver ts72xx_wdt_driver = {
> +	.probe = ts72xx_wdt_probe,
> +	.remove = __devexit_p(ts72xx_wdt_remove),
> +	.driver = {
> +		.name = "ts72xx-wdt",
> +	},
> +};

Nitpick: Tab align please.

> +
> +static __init int ts72xx_wdt_init(void)
> +{
> +	return platform_driver_register(&ts72xx_wdt_driver);
> +}
> +module_init(ts72xx_wdt_init);
> +
> +static __exit void ts72xx_wdt_exit(void)
> +{
> +	platform_driver_unregister(&ts72xx_wdt_driver);
> +}
> +module_exit(ts72xx_wdt_exit);
> +
> +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
> +MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:ts72xx-wdt");