[PATCH v4 05/12] watchdog: s3c2410: Make reset disable register optional

[Sam Protsenko <semen.protsenko@linaro.org>]

On new Exynos chips (e.g. Exynos850 and Exynos9) the
AUTOMATIC_WDT_RESET_DISABLE register was removed, and its value can be
thought of as "always 0x0". Add correspondig quirk bit, so that the
driver can omit accessing it if it's not present.

This commit doesn't bring any functional change to existing devices, but
merely provides an infrastructure for upcoming chips support.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
---
Changes in v4:
  - Added R-b tag by Guenter Roeck

Changes in v3:
  - Aligned arguments with opening parentheses
  - Added R-b tag by Krzysztof Kozlowski

Changes in v2:
  - Used quirks instead of callbacks for all added PMU registers
  - Used BIT() macro
  - Extracted splitting the s3c2410wdt_mask_and_disable_reset() function
    to separate patch
  - Extracted cleanup code to separate patch to minimize changes and
    ease the review and porting

 drivers/watchdog/s3c2410_wdt.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 0845c05034a1..2cc4923a98a5 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -59,10 +59,12 @@
 #define QUIRK_HAS_PMU_CONFIG			(1 << 0)
 #define QUIRK_HAS_RST_STAT			(1 << 1)
 #define QUIRK_HAS_WTCLRINT_REG			(1 << 2)
+#define QUIRK_HAS_PMU_AUTO_DISABLE		(1 << 3)
 
 /* These quirks require that we have a PMU register map */
 #define QUIRKS_HAVE_PMUREG			(QUIRK_HAS_PMU_CONFIG | \
-						 QUIRK_HAS_RST_STAT)
+						 QUIRK_HAS_RST_STAT | \
+						 QUIRK_HAS_PMU_AUTO_DISABLE)
 
 static bool nowayout	= WATCHDOG_NOWAYOUT;
 static int tmr_margin;
@@ -137,7 +139,7 @@ static const struct s3c2410_wdt_variant drv_data_exynos5250  = {
 	.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 	.rst_stat_bit = 20,
 	.quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
-		  | QUIRK_HAS_WTCLRINT_REG,
+		  | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
 };
 
 static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
@@ -147,7 +149,7 @@ static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
 	.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 	.rst_stat_bit = 9,
 	.quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
-		  | QUIRK_HAS_WTCLRINT_REG,
+		  | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
 };
 
 static const struct s3c2410_wdt_variant drv_data_exynos7 = {
@@ -157,7 +159,7 @@ static const struct s3c2410_wdt_variant drv_data_exynos7 = {
 	.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 	.rst_stat_bit = 23,	/* A57 WDTRESET */
 	.quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
-		  | QUIRK_HAS_WTCLRINT_REG,
+		  | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
 };
 
 static const struct of_device_id s3c2410_wdt_match[] = {
@@ -213,11 +215,13 @@ static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
 	if (mask)
 		val = mask_val;
 
-	ret = regmap_update_bits(wdt->pmureg,
-			wdt->drv_data->disable_reg,
-			mask_val, val);
-	if (ret < 0)
-		goto error;
+	if (wdt->drv_data->quirks & QUIRK_HAS_PMU_AUTO_DISABLE) {
+		ret = regmap_update_bits(wdt->pmureg,
+					 wdt->drv_data->disable_reg, mask_val,
+					 val);
+		if (ret < 0)
+			goto error;
+	}
 
 	ret = regmap_update_bits(wdt->pmureg,
 			wdt->drv_data->mask_reset_reg,
-- 
2.30.2