Re: [PATCH V9 2/3] watchdog: s3c2410_wdt: use syscon regmap interface to configure pmu register

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Hi Guenter Roeck,

Thanks for reviewing the patch.


On Mon, Nov 18, 2013 at 10:12 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> On Mon, Nov 18, 2013 at 03:19:48PM +0530, 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                     |  145 ++++++++++++++++++--
>>  3 files changed, 157 insertions(+), 10 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/watchdog/samsung-wdt.txt b/Documentation/devicetree/bindings/watchdog/samsung-wdt.txt
>> index 2aa486c..5dea363 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_sys_reg>;
>> +};
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index d1d53f3..0d272ae 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 23aad7c..42e0fd3 100644
>> --- a/drivers/watchdog/s3c2410_wdt.c
>> +++ b/drivers/watchdog/s3c2410_wdt.c
>> @@ -41,6 +41,8 @@
>>  #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
>> @@ -61,6 +63,10 @@
>>  #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;
>> @@ -84,6 +90,13 @@ 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 {
>> +     int disable_reg;
>> +     int mask_reset_reg;
>> +     int mask_bit;
>> +     u32 quirks;
>> +};
>> +
>>  struct s3c2410_wdt {
>>       struct device           *dev;
>>       struct clk              *clock;
>> @@ -94,7 +107,49 @@ 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 = 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 */
>>
>> @@ -111,6 +166,26 @@ 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)
>> +             return ret;
>> +
>> +     return regmap_update_bits(wdt->pmureg,
>> +                     wdt->drv_data->mask_reset_reg,
>> +                     mask_val, val);
>> +}
>> +
>>  static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
>>  {
>>       struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
>> @@ -332,6 +407,20 @@ 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;
>> @@ -354,6 +443,16 @@ 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");
>> @@ -444,6 +543,14 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
>>                (wtcon & S3C2410_WTCON_RSTEN) ? "en" : "dis",
>>                (wtcon & S3C2410_WTCON_INTEN) ? "en" : "dis");
>>
>> +     if (wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG) {
>> +             ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
>> +             if (ret < 0) {
>> +                     dev_err(wdt->dev, "failed to update pmu register");
>
> Hmm ... still not happy ;-). This message is the same for each call
> to s3c2410wdt_mask_and_disable_reset(). Why not create it there ?
> Sure, you'd have to decide if you want to use dev_warn() or dev_err(),
> but that would still be better than repeating the same message (and code)
> five times.
>
> The same is true for the if() statement. It might be worthwhile calling
> s3c2410wdt_mask_and_disable_reset() unconditionally and adding something
> like
>
>         if (!(wdt->drv_data->quirks & QUIRK_NEEDS_PMU_CONFIG))
>                 return 0;
>
> to it.
>

As Tomasz Figa suggested I handled the error conditions here
Please go through this link for your reference
https://patchwork.kernel.org/patch/3118771/

Best Wishes,
Leela Krishna.

> Thanks,
> Guenter
>
>> +                     goto err_cpufreq;
>> +             }
>> +     }
>> +
>>       return 0;
>>
>>   err_cpufreq:
>> @@ -459,8 +566,15 @@ 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)
>> +                     dev_warn(wdt->dev, "failed to update pmu register");
>> +     }
>> +
>>       watchdog_unregister_device(&wdt->wdt_device);
>>
>>       s3c2410wdt_cpufreq_deregister(wdt);
>> @@ -473,8 +587,15 @@ 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");
>> +     }
>> +
>>       s3c2410wdt_stop(&wdt->wdt_device);
>>  }
>>
>> @@ -482,12 +603,19 @@ 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)
>> +                     dev_warn(wdt->dev, "failed to update pmu register");
>> +     }
>> +
>>       /* Note that WTCNT doesn't need to be saved. */
>>       s3c2410wdt_stop(&wdt->wdt_device);
>>
>> @@ -496,6 +624,7 @@ 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. */
>> @@ -503,6 +632,12 @@ 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)
>> +                     dev_warn(wdt->dev, "failed to update pmu register");
>> +     }
>> +
>>       dev_info(dev, "watchdog %sabled\n",
>>               (wdt->wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
>>
>> @@ -513,18 +648,11 @@ 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",
>> @@ -540,4 +668,3 @@ MODULE_AUTHOR("Ben Dooks <ben@xxxxxxxxxxxx>, "
>>  MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
>>  MODULE_LICENSE("GPL");
>>  MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
>> -MODULE_ALIAS("platform:s3c2410-wdt");
>> --
>> 1.7.10.4
>>
>>
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