watchdog: s3c2410_wdt: use syscon regmap interface to configure pmu register

Add device tree support for exynos5250 and 5420 SoCs and use syscon regmap interface
to configure AUTOMATIC_WDT_RESET_DISABLE and MASK_WDT_RESET_REQUEST registers of PMU
to mask/unmask enable/disable of watchdog in probe and s2r scenarios.

Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

2 files changed, 146 insertions, 9 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 7a2fedab0fb5..c11a3387335d 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -196,6 +196,7 @@ config S3C2410_WATCHDOG
         tristate "S3C2410 Watchdog"
         depends on HAVE_S3C2410_WATCHDOG
         select WATCHDOG_CORE
+        select MFD_SYSCON if ARCH_EXYNOS5
         help
           Watchdog timer block in the Samsung SoCs. This will reboot
           the system when the timer expires with the watchdog enabled.
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 8beaa1799df6..64f5470a6a0e 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -40,6 +40,8 @@
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/of.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
 
 #define S3C2410_WTCON           0x00
 #define S3C2410_WTDAT           0x04
@@ -60,6 +62,10 @@
 #define CONFIG_S3C2410_WATCHDOG_ATBOOT          (0)
 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME    (15)
 
+#define EXYNOS5_WDT_DISABLE_REG_OFFSET          0x0408
+#define EXYNOS5_WDT_MASK_RESET_REG_OFFSET       0x040c
+#define QUIRK_HAS_PMU_CONFIG                    (1 << 0)
+
 static bool nowayout    = WATCHDOG_NOWAYOUT;
 static int tmr_margin;
 static int tmr_atboot   = CONFIG_S3C2410_WATCHDOG_ATBOOT;
@@ -83,6 +89,25 @@ MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, "
                         "0 to reboot (default 0)");
 MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug (default 0)");
 
+/**
+ * struct s3c2410_wdt_variant - Per-variant config data
+ *
+ * @disable_reg: Offset in pmureg for the register that disables the watchdog
+ * timer reset functionality.
+ * @mask_reset_reg: Offset in pmureg for the register that masks the watchdog
+ * timer reset functionality.
+ * @mask_bit: Bit number for the watchdog timer in the disable register and the
+ * mask reset register.
+ * @quirks: A bitfield of quirks.
+ */
+
+struct s3c2410_wdt_variant {
+        int disable_reg;
+        int mask_reset_reg;
+        int mask_bit;
+        u32 quirks;
+};
+
 struct s3c2410_wdt {
         struct device           *dev;
         struct clk              *clock;
@@ -93,7 +118,49 @@ struct s3c2410_wdt {
         unsigned long           wtdat_save;
         struct watchdog_device  wdt_device;
         struct notifier_block   freq_transition;
+        struct s3c2410_wdt_variant *drv_data;
+        struct regmap *pmureg;
+};
+
+static const struct s3c2410_wdt_variant drv_data_s3c2410 = {
+        .quirks = 0
+};
+
+#ifdef CONFIG_OF
+static const struct s3c2410_wdt_variant drv_data_exynos5250  = {
+        .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET,
+        .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET,
+        .mask_bit = 20,
+        .quirks = QUIRK_HAS_PMU_CONFIG
+};
+
+static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
+        .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET,
+        .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET,
+        .mask_bit = 0,
+        .quirks = QUIRK_HAS_PMU_CONFIG
+};
+
+static const struct of_device_id s3c2410_wdt_match[] = {
+        { .compatible = "samsung,s3c2410-wdt",
+          .data = &drv_data_s3c2410 },
+        { .compatible = "samsung,exynos5250-wdt",
+          .data = &drv_data_exynos5250 },
+        { .compatible = "samsung,exynos5420-wdt",
+          .data = &drv_data_exynos5420 },
+        {},
 };
+MODULE_DEVICE_TABLE(of, s3c2410_wdt_match);
+#endif
+
+static const struct platform_device_id s3c2410_wdt_ids[] = {
+        {
+                .name = "s3c2410-wdt",
+                .driver_data = (unsigned long)&drv_data_s3c2410,
+        },
+        {}
+};
+MODULE_DEVICE_TABLE(platform, s3c2410_wdt_ids);
 
 /* watchdog control routines */
 
@@ -110,6 +177,35 @@ static inline struct s3c2410_wdt *freq_to_wdt(struct notifier_block *nb)
         return container_of(nb, struct s3c2410_wdt, freq_transition);
 }
 
+static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
+{
+        int ret;
+        u32 mask_val = 1 << wdt->drv_data->mask_bit;
+        u32 val = 0;
+
+        /* No need to do anything if no PMU CONFIG needed */
+        if (!(wdt->drv_data->quirks & QUIRK_HAS_PMU_CONFIG))
+                return 0;
+
+        if (mask)
+                val = mask_val;
+
+        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,
+                        mask_val, val);
+ error:
+        if (ret < 0)
+                dev_err(wdt->dev, "failed to update reg(%d)\n", ret);
+
+        return ret;
+}
+
 static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
 {
         struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
@@ -328,6 +424,20 @@ static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt)
 }
 #endif
 
+/* s3c2410_get_wdt_driver_data */
+static inline struct s3c2410_wdt_variant *
+get_wdt_drv_data(struct platform_device *pdev)
+{
+        if (pdev->dev.of_node) {
+                const struct of_device_id *match;
+                match = of_match_node(s3c2410_wdt_match, pdev->dev.of_node);
+                return (struct s3c2410_wdt_variant *)match->data;
+        } else {
+                return (struct s3c2410_wdt_variant *)
+                        platform_get_device_id(pdev)->driver_data;
+        }
+}
+
 static int s3c2410wdt_probe(struct platform_device *pdev)
 {
         struct device *dev;
@@ -350,6 +460,16 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
         spin_lock_init(&wdt->lock);
         wdt->wdt_device = s3c2410_wdd;
 
+        wdt->drv_data = get_wdt_drv_data(pdev);
+        if (wdt->drv_data->quirks & QUIRK_HAS_PMU_CONFIG) {
+                wdt->pmureg = syscon_regmap_lookup_by_phandle(dev->of_node,
+                                                "samsung,syscon-phandle");
+                if (IS_ERR(wdt->pmureg)) {
+                        dev_err(dev, "syscon regmap lookup failed.\n");
+                        return PTR_ERR(wdt->pmureg);
+                }
+        }
+
         wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
         if (wdt_irq == NULL) {
                 dev_err(dev, "no irq resource specified\n");
@@ -418,6 +538,10 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
                 goto err_cpufreq;
         }
 
+        ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
+        if (ret < 0)
+                goto err_unregister;
+
         if (tmr_atboot && started == 0) {
                 dev_info(dev, "starting watchdog timer\n");
                 s3c2410wdt_start(&wdt->wdt_device);
@@ -442,6 +566,9 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
 
         return 0;
 
+ err_unregister:
+        watchdog_unregister_device(&wdt->wdt_device);
+
  err_cpufreq:
         s3c2410wdt_cpufreq_deregister(wdt);
 
@@ -455,8 +582,13 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
 
 static int s3c2410wdt_remove(struct platform_device *dev)
 {
+        int ret;
         struct s3c2410_wdt *wdt = platform_get_drvdata(dev);
 
+        ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
+        if (ret < 0)
+                return ret;
+
         watchdog_unregister_device(&wdt->wdt_device);
 
         s3c2410wdt_cpufreq_deregister(wdt);
@@ -471,6 +603,8 @@ static void s3c2410wdt_shutdown(struct platform_device *dev)
 {
         struct s3c2410_wdt *wdt = platform_get_drvdata(dev);
 
+        s3c2410wdt_mask_and_disable_reset(wdt, true);
+
         s3c2410wdt_stop(&wdt->wdt_device);
 }
 
@@ -478,12 +612,17 @@ static void s3c2410wdt_shutdown(struct platform_device *dev)
 
 static int s3c2410wdt_suspend(struct device *dev)
 {
+        int ret;
         struct s3c2410_wdt *wdt = dev_get_drvdata(dev);
 
         /* Save watchdog state, and turn it off. */
         wdt->wtcon_save = readl(wdt->reg_base + S3C2410_WTCON);
         wdt->wtdat_save = readl(wdt->reg_base + S3C2410_WTDAT);
 
+        ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
+        if (ret < 0)
+                return ret;
+
         /* Note that WTCNT doesn't need to be saved. */
         s3c2410wdt_stop(&wdt->wdt_device);
 
@@ -492,6 +631,7 @@ static int s3c2410wdt_suspend(struct device *dev)
 
 static int s3c2410wdt_resume(struct device *dev)
 {
+        int ret;
         struct s3c2410_wdt *wdt = dev_get_drvdata(dev);
 
         /* Restore watchdog state. */
@@ -499,6 +639,10 @@ static int s3c2410wdt_resume(struct device *dev)
         writel(wdt->wtdat_save, wdt->reg_base + S3C2410_WTCNT);/* Reset count */
         writel(wdt->wtcon_save, wdt->reg_base + S3C2410_WTCON);
 
+        ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
+        if (ret < 0)
+                return ret;
+
         dev_info(dev, "watchdog %sabled\n",
                 (wdt->wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
 
@@ -509,18 +653,11 @@ static int s3c2410wdt_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(s3c2410wdt_pm_ops, s3c2410wdt_suspend,
                         s3c2410wdt_resume);
 
-#ifdef CONFIG_OF
-static const struct of_device_id s3c2410_wdt_match[] = {
-        { .compatible = "samsung,s3c2410-wdt" },
-        {},
-};
-MODULE_DEVICE_TABLE(of, s3c2410_wdt_match);
-#endif
-
 static struct platform_driver s3c2410wdt_driver = {
         .probe          = s3c2410wdt_probe,
         .remove         = s3c2410wdt_remove,
         .shutdown       = s3c2410wdt_shutdown,
+        .id_table       = s3c2410_wdt_ids,
         .driver         = {
                 .owner  = THIS_MODULE,
                 .name   = "s3c2410-wdt",
@@ -535,4 +672,3 @@ MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
               "Dimitry Andric <dimitry.andric@tomtom.com>");
 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:s3c2410-wdt");