linux-kernel - Re: [PATCH v4 1/4] clk: qcom: branch: Add clk_branch2_mdio

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Message-ID: <p7m4fi53nc75rjnmxdrukaitaddvq4vgvpydiyjmem4g2leyih@uohiocu35w2u>
Date:   Thu, 17 Aug 2023 20:29:10 -0700
From:   Bjorn Andersson <andersson@...nel.org>
To:     Luo Jie <quic_luoj@...cinc.com>
Cc:     agross@...nel.org, konrad.dybcio@...aro.org,
        mturquette@...libre.com, sboyd@...nel.org, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        catalin.marinas@....com, will@...nel.org, p.zabel@...gutronix.de,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        quic_srichara@...cinc.com
Subject: Re: [PATCH v4 1/4] clk: qcom: branch: Add clk_branch2_mdio_ops

On Tue, Aug 15, 2023 at 04:52:02PM +0800, Luo Jie wrote:
> Add the clk_branch2_mdio_ops for supporting clock controller
> where the hardware register is accessed by MDIO bus, and the
> spin clock can't be used because of sleep during the MDIO

spin clock?

I believe you're trying to say that the underlying access to the MDIO
bus can not be done in non-sleepable context and we can therefor not use
enable/disable to operate it?

> operation.
> 
> The clock is enabled by the .prepare instead of .enable when
> the clk_branch2_mdio_ops is used.
> 
> Signed-off-by: Luo Jie <quic_luoj@...cinc.com>
> ---
>  drivers/clk/qcom/clk-branch.c | 7 +++++++
>  drivers/clk/qcom/clk-branch.h | 1 +
>  2 files changed, 8 insertions(+)
> 
> diff --git a/drivers/clk/qcom/clk-branch.c b/drivers/clk/qcom/clk-branch.c
> index fc4735f74f0f..5e08c026ca4a 100644
> --- a/drivers/clk/qcom/clk-branch.c
> +++ b/drivers/clk/qcom/clk-branch.c
> @@ -153,3 +153,10 @@ const struct clk_ops clk_branch_simple_ops = {
>  	.is_enabled = clk_is_enabled_regmap,
>  };
>  EXPORT_SYMBOL_GPL(clk_branch_simple_ops);
> +
> +const struct clk_ops clk_branch2_mdio_ops = {
> +	.prepare = clk_branch2_enable,
> +	.unprepare = clk_branch2_disable,

I see none of the clocks specify halt_check, which would imply that
these two calls just turns into clk_enable_regmap() and
clk_disable_regmap().

So, isn't this then equivalent to clk_branch_simple_ops?

Regards,
Bjorn

> +	.is_prepared = clk_is_enabled_regmap,
> +};
> +EXPORT_SYMBOL_GPL(clk_branch2_mdio_ops);
> diff --git a/drivers/clk/qcom/clk-branch.h b/drivers/clk/qcom/clk-branch.h
> index 0cf800b9d08d..4b006e8eec5e 100644
> --- a/drivers/clk/qcom/clk-branch.h
> +++ b/drivers/clk/qcom/clk-branch.h
> @@ -85,6 +85,7 @@ extern const struct clk_ops clk_branch_ops;
>  extern const struct clk_ops clk_branch2_ops;
>  extern const struct clk_ops clk_branch_simple_ops;
>  extern const struct clk_ops clk_branch2_aon_ops;
> +extern const struct clk_ops clk_branch2_mdio_ops;
>  
>  #define to_clk_branch(_hw) \
>  	container_of(to_clk_regmap(_hw), struct clk_branch, clkr)
> -- 
> 2.17.1
>