linux-kernel - Re: [PATCH 2/2] thermal: armada-thermal: clear reset in armadaxp

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Message-ID: <BN8PR10MB3379AC7EF5E941B9234B7E628C420@BN8PR10MB3379.namprd10.prod.outlook.com>
Date:   Tue, 3 Dec 2019 16:36:29 +0000
From:   Zak Hays <zak.hays@...mark.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
CC:     Zhang Rui <rui.zhang@...el.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amit.kucheria@...durent.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] thermal: armada-thermal: clear reset in armadaxp_init

Hi Miquèl,

>The format of your patch is strange, there are additional empty lines
>which are problematic.

Apologies for the formatting. I'll try to fix that in that next patch set.

>Do you really want to write this register twice? Shouldn't you get rid
>of the first regmap_write() above?

I'm writing the register twice in order to pulse the reset line and ensure the block is reset at init. This is similar to what was done in the driver previously:

        /* Reset the sensor */
        reg = readl_relaxed(priv->control1);
        writel((reg | PMU_TDC0_SW_RST_MASK), priv->control1);      <= Set the reset bit

        writel(reg, priv->control1);                                                       <= Immediately clear the bit

I'm a little unsure that setting then immediately clearing reset is enough time for the block to do a full reset but I can't find anything in AXP's documentation to indicate a correct reset time. As such, I just emulated the original process from earlier kernel versions. If you believe that a udelay should be added, I can add one in the next patch set.

Thanks!
Zak


________________________________________
From: Miquel Raynal <miquel.raynal@...tlin.com>
Sent: Wednesday, November 27, 2019 6:00 AM
To: Zak Hays
Cc: Zhang Rui; Eduardo Valentin; Daniel Lezcano; Amit Kucheria; linux-pm@...r.kernel.org; linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] thermal: armada-thermal: clear reset in armadaxp_init

Hi Zak,

Zak Hays <zak.hays@...mark.com> wrote on Tue, 26 Nov 2019 14:54:11
+0000:

> The reset bit needs to be cleared in the init sequence otherwise it
>
> holds the block in reset.

"thermal: armada: " is the right prefix for your title

Your Signed-off-by should be here (git commit --amend -s)

The format of your patch is strange, there are additional empty lines
which are problematic.

>
> ---
>
>  drivers/thermal/armada_thermal.c | 3 +++
>
>  1 file changed, 3 insertions(+)
>
>
>
> diff --git a/drivers/thermal/armada_thermal.c b/drivers/thermal/armada_thermal.c
>
> index 88363812033c..8c4d1244ee7a 100644
>
> --- a/drivers/thermal/armada_thermal.c
>
> +++ b/drivers/thermal/armada_thermal.c
>
> @@ -155,6 +155,9 @@ static void armadaxp_init(struct platform_device *pdev,
>
>
>
>          regmap_write(priv->syscon, data->syscon_control1_off, reg);
>
>
>
> +       reg &= ~PMU_TDC0_SW_RST_MASK;
>
> +       regmap_write(priv->syscon, data->syscon_control1_off, reg);
>
> +

Do you really want to write this register twice? Shouldn't you get rid
of the first regmap_write() above?

>
>          /* Enable the sensor */
>
>          regmap_read(priv->syscon, data->syscon_status_off, &reg);
>
>          reg &= ~PMU_TM_DISABLE_MASK;
>

In your next iteration, please use the '-v2' option with
git-format-patch to get titles starting with "[PATCH v2 x/2] ..."
automatically. Also write a changelog below the three dots '---'.

Thanks,
Miquèl