linux-kernel - Re: [PATCH v3 13/14] rtc: pcf2127: add flag for watchdog register value read support

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Date:   Sat, 7 Jan 2023 19:47:34 +0100
From:   Bruno Thomsen <bruno.thomsen@...il.com>
To:     Hugo Villeneuve <hugo@...ovil.com>
Cc:     a.zummo@...ertech.it, alexandre.belloni@...tlin.com,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        linux-rtc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Hugo Villeneuve <hvilleneuve@...onoff.com>
Subject: Re: [PATCH v3 13/14] rtc: pcf2127: add flag for watchdog register
 value read support

Den tor. 15. dec. 2022 kl. 16.19 skrev Hugo Villeneuve <hugo@...ovil.com>:
>
> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
>
> The watchdog value register cannot be read on the PCF2131 after being
> set.
>
> Add a new flag to identify which variant has read access to this
> register, and use this flag to selectively test if watchdog timer was
> started by bootloader.
>
> Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>

Reviewed-by: Bruno Thomsen <bruno.thomsen@...il.com>

> ---
>  drivers/rtc/rtc-pcf2127.c | 20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 3fd2fee4978b..1d2b5c9e6757 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -214,6 +214,7 @@ struct pcf21xx_config {
>         int max_register;
>         unsigned int has_nvmem:1;
>         unsigned int has_bit_wd_ctl_cd0:1;
> +       unsigned int wd_val_reg_readable:1; /* If watchdog value register can be read. */
>         unsigned int has_int_a_b:1; /* PCF2131 supports two interrupt outputs. */
>         unsigned int has_reset_reg:1; /* If variant has a reset register. */
>         u8 regs_td_base; /* Time/data base registers. */
> @@ -511,7 +512,6 @@ static const struct watchdog_ops pcf2127_watchdog_ops = {
>
>  static int pcf2127_watchdog_init(struct device *dev, struct pcf2127 *pcf2127)
>  {
> -       u32 wdd_timeout;
>         int ret;
>
>         if (!IS_ENABLED(CONFIG_WATCHDOG) ||
> @@ -539,12 +539,17 @@ static int pcf2127_watchdog_init(struct device *dev, struct pcf2127 *pcf2127)
>         watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
>
>         /* Test if watchdog timer is started by bootloader */
> -       ret = regmap_read(pcf2127->regmap, pcf2127->cfg->reg_wd_val, &wdd_timeout);
> -       if (ret)
> -               return ret;
> +       if (pcf2127->cfg->wd_val_reg_readable) {
> +               u32 wdd_timeout;
> +
> +               ret = regmap_read(pcf2127->regmap, pcf2127->cfg->reg_wd_val,
> +                                 &wdd_timeout);
> +               if (ret)
> +                       return ret;
>
> -       if (wdd_timeout)
> -               set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
> +               if (wdd_timeout)
> +                       set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
> +       }
>
>         return devm_watchdog_register_device(dev, &pcf2127->wdd);
>  }
> @@ -953,6 +958,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
>                 .max_register = 0x1d,
>                 .has_nvmem = 1,
>                 .has_bit_wd_ctl_cd0 = 1,
> +               .wd_val_reg_readable = 1,
>                 .has_int_a_b = 0,
>                 .has_reset_reg = 0,
>                 .regs_td_base = PCF2127_REG_TIME_DATE_BASE,
> @@ -980,6 +986,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
>                 .max_register = 0x19,
>                 .has_nvmem = 0,
>                 .has_bit_wd_ctl_cd0 = 0,
> +               .wd_val_reg_readable = 1,
>                 .has_int_a_b = 0,
>                 .has_reset_reg = 0,
>                 .regs_td_base = PCF2127_REG_TIME_DATE_BASE,
> @@ -1007,6 +1014,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
>                 .max_register = 0x36,
>                 .has_nvmem = 0,
>                 .has_bit_wd_ctl_cd0 = 0,
> +               .wd_val_reg_readable = 0,
>                 .has_int_a_b = 1,
>                 .has_reset_reg = 1,
>                 .regs_td_base = PCF2131_REG_TIME_DATE_BASE,
> --
> 2.30.2
>