netdev - Re: [PATCH 8/8] clk: qcom: gcc-sm8150: Use PWRSTS_ON (only) as a workaround for emac gdsc

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Date:   Mon, 31 Jan 2022 18:05:18 -0600
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Bhupesh Sharma <bhupesh.sharma@...aro.org>
Cc:     linux-arm-msm@...r.kernel.org, bhupesh.linux@...il.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        robh+dt@...nel.org, agross@...nel.org, sboyd@...nel.org,
        tdas@...eaurora.org, mturquette@...libre.com,
        linux-clk@...r.kernel.org, davem@...emloft.net,
        netdev@...r.kernel.org
Subject: Re: [PATCH 8/8] clk: qcom: gcc-sm8150: Use PWRSTS_ON (only) as a
 workaround for emac gdsc

On Wed 26 Jan 16:17 CST 2022, Bhupesh Sharma wrote:

> EMAC GDSC currently has issues (seen on SA8155p-ADP) when its
> turn'ed ON, once its already in OFF state. So, use PWRSTS_ON
> state (only) as a workaround for now.
> 
> Cc: Bjorn Andersson <bjorn.andersson@...aro.org>
> Cc: Stephen Boyd <sboyd@...nel.org>
> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@...aro.org>
> ---
>  drivers/clk/qcom/gcc-sm8150.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/qcom/gcc-sm8150.c b/drivers/clk/qcom/gcc-sm8150.c
> index 2e71afed81fd..fd7e931d3c09 100644
> --- a/drivers/clk/qcom/gcc-sm8150.c
> +++ b/drivers/clk/qcom/gcc-sm8150.c
> @@ -3449,12 +3449,16 @@ static struct clk_branch gcc_video_xo_clk = {
>  	},
>  };
>  
> +/* To Do: EMAC GDSC currently has issues when its turn'ed ON, once
> + * its already in OFF state. So use PWRSTS_ON state (only) as a
> + * workaround for now.

So you're not able to turn on the GDSC after turning it off?

> + */
>  static struct gdsc emac_gdsc = {
>  	.gdscr = 0x6004,
>  	.pd = {
>  		.name = "emac_gdsc",
>  	},
> -	.pwrsts = PWRSTS_OFF_ON,
> +	.pwrsts = PWRSTS_ON,

Doesn't this tell the gdsc driver that the only state supported is "on"
and hence prohibit you from turning it on in the first place?

>  	.flags = POLL_CFG_GDSCR,

You could add ALWAYS_ON to .flags, but we need a better description of
the actual problem that you're working around.

Regards,
Bjorn

>  };
>  
> -- 
> 2.34.1
>