linux-kernel - Re: [PATCH 2/3] drivers: thermal: tsens: Add watchdog support

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Date:   Thu, 14 Nov 2019 14:38:11 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Amit Kucheria <amit.kucheria@...aro.org>,
        Andy Gross <agross@...nel.org>, bjorn.andersson@...aro.org,
        edubezval@...il.com, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, sivaa@...eaurora.org
Cc:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amit.kucheria@...durent.com>,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/3] drivers: thermal: tsens: Add watchdog support

Quoting Amit Kucheria (2019-11-11 11:21:28)
> TSENS IP v2.3 onwards adds support for a watchdog to detect if the TSENS
> HW FSM is frozen. Add support to detect and restart the FSM in the

Maybe 'frozen' is an ambiguous term? Maybe 'stuck' or 'has stopped
making progress'?

> driver. The watchdog is configured by the bootloader, we just enable the
> feature in the kernel.

Does it work to enable it if we don't configure it in the bootloader?

> 
> Signed-off-by: Amit Kucheria <amit.kucheria@...aro.org>
> ---
>  drivers/thermal/qcom/tsens-common.c | 41 +++++++++++++++++++++++++++++
>  drivers/thermal/qcom/tsens-v2.c     | 10 +++++++
>  drivers/thermal/qcom/tsens.h        | 12 +++++++++
>  3 files changed, 63 insertions(+)
> 
> diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
> index 2989cb952cdb..9432518502a7 100644
> --- a/drivers/thermal/qcom/tsens-common.c
> +++ b/drivers/thermal/qcom/tsens-common.c
> @@ -794,6 +820,21 @@ int __init init_common(struct tsens_priv *priv)
>                 }
>         }
>  
> +       if (tsens_version(priv) > VER_1_X &&  ver_minor > 2) {
> +               /* Watchdog is present only on v2.3+ */
> +               for (i = 0, j = WDOG_BARK_STATUS; j <= CC_MON_MASK; i++, j++) {

The variable 'i' is not actually used in this loop. What's going on?

> +                       priv->rf[j] = devm_regmap_field_alloc(dev, priv->tm_map,
> +                                                             priv->fields[j]);
> +                       if (IS_ERR(priv->rf[j])) {
> +                               ret = PTR_ERR(priv->rf[j]);
> +                               goto err_put_device;
> +                       }
> +               }
> +               /* Enable WDOG and disable cycle completion monitoring */
> +               regmap_field_write(priv->rf[WDOG_BARK_MASK], 0);
> +               regmap_field_write(priv->rf[CC_MON_MASK], 1);
> +       }