[PATCH v4 3/3] iTCO_wdt: Add support for TCO on Intel Sunrisepoint

[Matt Fleming <matt@codeblueprint.co.uk>]

From: Matt Fleming <matt.fleming@intel.com>

The revision of the watchdog hardware in Sunrisepoint necessitates a new
"version" inside the TCO watchdog driver because some of the register
layouts have changed.

Also update the Kconfig entry to select both the LPC and SMBus drivers
since the TCO device is on the SMBus in Sunrisepoint.

Cc: Wim Van Sebroeck <wim@iguana.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
---

v4:
 - Explicitly list versions in iTCO_wdt_probe()
 - Delete the now superfluous 'ret' variable in iTCO_wdt_unset_NO_REBOOT_bit()

v3:
 - Added Guenter's Review tag

v2: 
 - Explicitly list TCO versions and their "no reboot" bits in the switch
   statement in no_reboot_bit()
 - Use a switch/case statement when clearing status bits instead of
   convoluted if/else branching
 - Select both of the bus drivers instead of using depends

 drivers/watchdog/Kconfig    |  3 +-
 drivers/watchdog/iTCO_wdt.c | 71 ++++++++++++++++++++++++++++-----------------
 2 files changed, 46 insertions(+), 28 deletions(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 241fafde42cb..55c4b5b0a317 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -797,7 +797,8 @@ config ITCO_WDT
 	tristate "Intel TCO Timer/Watchdog"
 	depends on (X86 || IA64) && PCI
 	select WATCHDOG_CORE
-	select LPC_ICH
+	select LPC_ICH if !EXPERT
+	select I2C_I801 if !EXPERT
 	---help---
 	  Hardware driver for the intel TCO timer based watchdog devices.
 	  These drivers are included in the Intel 82801 I/O Controller
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index a94401b2deca..0acc6c5f729d 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -145,59 +145,67 @@ static inline unsigned int ticks_to_seconds(int ticks)
 	return iTCO_wdt_private.iTCO_version == 3 ? ticks : (ticks * 6) / 10;
 }
 
+static inline u32 no_reboot_bit(void)
+{
+	u32 enable_bit;
+
+	switch (iTCO_wdt_private.iTCO_version) {
+	case 3:
+		enable_bit = 0x00000010;
+		break;
+	case 2:
+		enable_bit = 0x00000020;
+		break;
+	case 4:
+	case 1:
+	default:
+		enable_bit = 0x00000002;
+		break;
+	}
+
+	return enable_bit;
+}
+
 static void iTCO_wdt_set_NO_REBOOT_bit(void)
 {
 	u32 val32;
 
 	/* Set the NO_REBOOT bit: this disables reboots */
-	if (iTCO_wdt_private.iTCO_version == 3) {
-		val32 = readl(iTCO_wdt_private.gcs_pmc);
-		val32 |= 0x00000010;
-		writel(val32, iTCO_wdt_private.gcs_pmc);
-	} else if (iTCO_wdt_private.iTCO_version == 2) {
+	if (iTCO_wdt_private.iTCO_version >= 2) {
 		val32 = readl(iTCO_wdt_private.gcs_pmc);
-		val32 |= 0x00000020;
+		val32 |= no_reboot_bit();
 		writel(val32, iTCO_wdt_private.gcs_pmc);
 	} else if (iTCO_wdt_private.iTCO_version == 1) {
 		pci_read_config_dword(iTCO_wdt_private.pdev, 0xd4, &val32);
-		val32 |= 0x00000002;
+		val32 |= no_reboot_bit();
 		pci_write_config_dword(iTCO_wdt_private.pdev, 0xd4, val32);
 	}
 }
 
 static int iTCO_wdt_unset_NO_REBOOT_bit(void)
 {
-	int ret = 0;
-	u32 val32;
+	u32 enable_bit = no_reboot_bit();
+	u32 val32 = 0;
 
 	/* Unset the NO_REBOOT bit: this enables reboots */
-	if (iTCO_wdt_private.iTCO_version == 3) {
-		val32 = readl(iTCO_wdt_private.gcs_pmc);
-		val32 &= 0xffffffef;
-		writel(val32, iTCO_wdt_private.gcs_pmc);
-
-		val32 = readl(iTCO_wdt_private.gcs_pmc);
-		if (val32 & 0x00000010)
-			ret = -EIO;
-	} else if (iTCO_wdt_private.iTCO_version == 2) {
+	if (iTCO_wdt_private.iTCO_version >= 2) {
 		val32 = readl(iTCO_wdt_private.gcs_pmc);
-		val32 &= 0xffffffdf;
+		val32 &= ~enable_bit;
 		writel(val32, iTCO_wdt_private.gcs_pmc);
 
 		val32 = readl(iTCO_wdt_private.gcs_pmc);
-		if (val32 & 0x00000020)
-			ret = -EIO;
 	} else if (iTCO_wdt_private.iTCO_version == 1) {
 		pci_read_config_dword(iTCO_wdt_private.pdev, 0xd4, &val32);
-		val32 &= 0xfffffffd;
+		val32 &= ~enable_bit;
 		pci_write_config_dword(iTCO_wdt_private.pdev, 0xd4, val32);
 
 		pci_read_config_dword(iTCO_wdt_private.pdev, 0xd4, &val32);
-		if (val32 & 0x00000002)
-			ret = -EIO;
 	}
 
-	return ret; /* returns: 0 = OK, -EIO = Error */
+	if (val32 & enable_bit)
+		return -EIO;
+
+	return 0;
 }
 
 static int iTCO_wdt_start(struct watchdog_device *wd_dev)
@@ -503,12 +511,21 @@ static int iTCO_wdt_probe(struct platform_device *dev)
 		pdata->name, pdata->version, (u64)TCOBASE);
 
 	/* Clear out the (probably old) status */
-	if (iTCO_wdt_private.iTCO_version == 3) {
+	switch (iTCO_wdt_private.iTCO_version) {
+	case 4:
+		outw(0x0008, TCO1_STS);	/* Clear the Time Out Status bit */
+		outw(0x0002, TCO2_STS);	/* Clear SECOND_TO_STS bit */
+		break;
+	case 3:
 		outl(0x20008, TCO1_STS);
-	} else {
+		break;
+	case 2:
+	case 1:
+	default:
 		outw(0x0008, TCO1_STS);	/* Clear the Time Out Status bit */
 		outw(0x0002, TCO2_STS);	/* Clear SECOND_TO_STS bit */
 		outw(0x0004, TCO2_STS);	/* Clear BOOT_STS bit */
+		break;
 	}
 
 	iTCO_wdt_watchdog_dev.bootstatus = 0;
-- 
2.1.0