[WATCHDOG] it8712f_wdt support for 16-bit timeout values, WDIOC_GETSTATUS

This patch adds support for 16-bit watchdog timeout values which are
available in chip revisions >= 0x08. Values <= 65535 are seconds precision,
otherwise minutes precision is used up to a maximum value of 3932100. Added
implementation for WDIOC_GETSTATUS which checks the WDT status bit in the
WDT control register.

Signed-off-by: Andrew Paprocki <andrew@ishiboo.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/it8712f_wdt.c

@@ -7,7 +7,8 @@
  *
  *	drivers/char/watchdog/scx200_wdt.c
  *	drivers/hwmon/it87.c
- *	IT8712F EC-LPC I/O Preliminary Specification 0.9.2.pdf
+ *	IT8712F EC-LPC I/O Preliminary Specification 0.8.2
+ *	IT8712F EC-LPC I/O Preliminary Specification 0.9.3
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License as
@@ -40,6 +41,7 @@ MODULE_DESCRIPTION("IT8712F Watchdog Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 
+static int max_units = 255;
 static int margin = 60;		/* in seconds */
 module_param(margin, int, 0);
 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
@@ -51,6 +53,7 @@ MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
 static struct semaphore it8712f_wdt_sem;
 static unsigned expect_close;
 static spinlock_t io_lock;
+static unsigned char revision;
 
 /* Dog Food address - We use the game port address */
 static unsigned short address;
@@ -108,6 +111,15 @@ superio_inw(int reg)
 	return val;
 }
 
+static void
+superio_outw(int val, int reg)
+{
+	outb(reg++, REG);
+	outb((val >> 8) & 0xff, VAL);
+	outb(reg, REG);
+	outb(val & 0xff, VAL);
+}
+
 static inline void
 superio_select(int ldn)
 {
@@ -143,15 +155,33 @@ static void
 it8712f_wdt_update_margin(void)
 {
 	int config = WDT_OUT_KRST | WDT_OUT_PWROK;
-
-	printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
-
-	/* The timeout register only has 8bits wide */
-	if (margin < 256)
-		config |= WDT_UNIT_SEC;	/* else UNIT are MINUTES */
+	int units = margin;
+
+	/* Switch to minutes precision if the configured margin
+	 * value does not fit within the register width.
+	 */
+	if (units <= max_units) {
+		config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
+		printk(KERN_INFO NAME ": timer margin %d seconds\n", units);
+	} else {
+		units /= 60;
+		printk(KERN_INFO NAME ": timer margin %d minutes\n", units);
+	}
 	superio_outb(config, WDT_CONFIG);
 
-	superio_outb((margin > 255) ? (margin / 60) : margin, WDT_TIMEOUT);
+	if (revision >= 0x08)
+		superio_outw(units, WDT_TIMEOUT);
+	else
+		superio_outb(units, WDT_TIMEOUT);
+}
+
+static int
+it8712f_wdt_get_status(void)
+{
+	if (superio_inb(WDT_CONTROL) & 0x01)
+		return WDIOF_CARDRESET;
+	else
+		return 0;
 }
 
 static void
@@ -234,7 +264,7 @@ it8712f_wdt_ioctl(struct inode *inode, struct file *file,
 		.firmware_version = 1,
 		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 	};
-	int new_margin;
+	int value;
 
 	switch (cmd) {
 	default:
@@ -244,17 +274,27 @@ it8712f_wdt_ioctl(struct inode *inode, struct file *file,
 			return -EFAULT;
 		return 0;
 	case WDIOC_GETSTATUS:
+		superio_enter();
+		superio_select(LDN_GPIO);
+
+		value = it8712f_wdt_get_status();
+
+		superio_exit();
+
+		return put_user(value, p);
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, p);
 	case WDIOC_KEEPALIVE:
 		it8712f_wdt_ping();
 		return 0;
 	case WDIOC_SETTIMEOUT:
-		if (get_user(new_margin, p))
+		if (get_user(value, p))
 			return -EFAULT;
-		if (new_margin < 1)
+		if (value < 1)
+			return -EINVAL;
+		if (value > (max_units * 60))
 			return -EINVAL;
-		margin = new_margin;
+		margin = value;
 		superio_enter();
 		superio_select(LDN_GPIO);
 
@@ -262,6 +302,7 @@ it8712f_wdt_ioctl(struct inode *inode, struct file *file,
 
 		superio_exit();
 		it8712f_wdt_ping();
+		/* Fall through */
 	case WDIOC_GETTIMEOUT:
 		if (put_user(margin, p))
 			return -EFAULT;
@@ -336,9 +377,18 @@ it8712f_wdt_find(unsigned short *address)
 	}
 
 	err = 0;
-	printk(KERN_DEBUG NAME ": Found IT%04xF chip revision %d - "
+	revision = superio_inb(DEVREV) & 0x0f;
+
+	/* Later revisions have 16-bit values per datasheet 0.9.1 */
+	if (revision >= 0x08)
+		max_units = 65535;
+
+	if (margin > (max_units * 60))
+		margin = (max_units * 60);
+
+	printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
 		"using DogFood address 0x%x\n",
-		chip_type, superio_inb(DEVREV) & 0x0f, *address);
+		chip_type, revision, *address);
 
 exit:
 	superio_exit();