Re: [PATCH V10 2/3] watchdog: s3c2410_wdt: use syscon regmap interface to configure pmu register

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On 11/27/2013 03:50 AM, Leela Krishna Amudala wrote:
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@xxxxxxxxxxx>
---
  .../devicetree/bindings/watchdog/samsung-wdt.txt   |   21 ++-
  drivers/watchdog/Kconfig                           |    1 +
  drivers/watchdog/s3c2410_wdt.c                     |  164 ++++++++++++++++++--
  3 files changed, 176 insertions(+), 10 deletions(-)

diff --git a/Documentation/devicetree/bindings/watchdog/samsung-wdt.txt b/Documentation/devicetree/bindings/watchdog/samsung-wdt.txt
index 2aa486c..cfff375 100644
--- a/Documentation/devicetree/bindings/watchdog/samsung-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/samsung-wdt.txt
@@ -5,10 +5,29 @@ after a preset amount of time during which the WDT reset event has not
  occurred.

  Required properties:
-- compatible : should be "samsung,s3c2410-wdt"
+- compatible : should be one among the following
+	(a) "samsung,s3c2410-wdt" for Exynos4 and previous SoCs
+	(b) "samsung,exynos5250-wdt" for Exynos5250
+	(c) "samsung,exynos5420-wdt" for Exynos5420
+
  - reg : base physical address of the controller and length of memory mapped
  	region.
  - interrupts : interrupt number to the cpu.
+- samsung,syscon-phandle : reference to syscon node (This property required only
+	in case of compatible being "samsung,exynos5250-wdt" or "samsung,exynos5420-wdt".
+	In case of Exynos5250 and 5420 this property points to syscon node holding the PMU
+	base address)

  Optional properties:
  - timeout-sec : contains the watchdog timeout in seconds.
+
+Example:
+
+watchdog@101D0000 {
+	compatible = "samsung,exynos5250-wdt";
+	reg = <0x101D0000 0x100>;
+	interrupts = <0 42 0>;
+	clocks = <&clock 336>;
+	clock-names = "watchdog";
+	samsung,syscon-phandle = <&pmu_syscon>;
+};
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 5be6e91..24738c0 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -188,6 +188,7 @@ 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 7d8fd04..b00b535 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 WDT_DISABLE_REG_OFFSET		0x0408
+#define WDT_MASK_RESET_REG_OFFSET	0x040c
+#define QUIRK_NEEDS_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;
@@ -93,8 +118,50 @@ 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 = WDT_DISABLE_REG_OFFSET,
+	.mask_reset_reg = WDT_MASK_RESET_REG_OFFSET,
+	.mask_bit = 20,
+	.quirks = QUIRK_NEEDS_PMU_CONFIG
+};
+
+static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
+	.disable_reg = WDT_DISABLE_REG_OFFSET,
+	.mask_reset_reg = WDT_MASK_RESET_REG_OFFSET,
+	.mask_bit = 0,
+	.quirks = QUIRK_NEEDS_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 */

  #define DBG(fmt, ...)					\
@@ -110,6 +177,32 @@ 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;
+
+	if (mask)
+		val = mask_val;
+
+	ret = regmap_update_bits(wdt->pmureg,
+			wdt->drv_data->disable_reg,
+			mask_val, val);
+	if (ret < 0) {
+		dev_err(wdt->dev, "failed to update reg(%d)\n", ret);
+		return ret;
+	}
+
Since you are now doing something in the error handler,
you might want to follow coding style rules:

	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);
@@ -331,6 +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;
@@ -353,6 +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_NEEDS_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");
@@ -421,6 +538,12 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
  		goto err_cpufreq;
  	}

+	if (wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG) {
+		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);
@@ -445,6 +568,9 @@ static int s3c2410wdt_probe(struct platform_device *pdev)

  	return 0;

+ err_unregister:
+	watchdog_unregister_device(&wdt->wdt_device);
+
   err_cpufreq:
  	s3c2410wdt_cpufreq_deregister(wdt);

@@ -458,8 +584,15 @@ 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);

+	if (wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG) {
+		ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
+		if (ret < 0)
+			return ret;
+	}
+
  	watchdog_unregister_device(&wdt->wdt_device);

  	s3c2410wdt_cpufreq_deregister(wdt);
@@ -472,8 +605,15 @@ static int s3c2410wdt_remove(struct platform_device *dev)

  static void s3c2410wdt_shutdown(struct platform_device *dev)
  {
+	int ret;
  	struct s3c2410_wdt *wdt = platform_get_drvdata(dev);

+	if (wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG) {
+		ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
+		if (ret < 0)
+			dev_warn(wdt->dev, "failed to update pmu register");

Duplicate error message.

+	}
+
  	s3c2410wdt_stop(&wdt->wdt_device);
  }

@@ -481,12 +621,19 @@ 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);

+	if (wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG) {
+		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);

@@ -495,6 +642,7 @@ 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. */
@@ -502,6 +650,12 @@ 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);

+	if (wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG) {
+		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");

@@ -512,18 +666,11 @@ 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",
@@ -538,4 +685,3 @@ MODULE_AUTHOR("Ben Dooks <ben@xxxxxxxxxxxx>, "
  	      "Dimitry Andric <dimitry.andric@xxxxxxxxxx>");
  MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
  MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:s3c2410-wdt");


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