linux-kernel - Re: [PATCH v2] clk: qcom: clk-smd-rpm: Fix the reported rate of branches

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Message-ID: <20170713180332.GC22780@codeaurora.org>
Date:   Thu, 13 Jul 2017 14:56:18 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Georgi Djakov <georgi.djakov@...aro.org>
Cc:     mturquette@...libre.com, andy.gross@...aro.org,
        architt@...eaurora.org, hverkuil@...all.nl,
        bjorn.andersson@...aro.org, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] clk: qcom: clk-smd-rpm: Fix the reported rate of
 branches

On 07/13, Georgi Djakov wrote:
> As there is no way to actually query the hardware for the current clock
> rate, now racalc_rate() just returns the last rate that was previously
> set. But if the rate was not set yet, we return the bogus rate of 1000Hz.
> 
> The branch clocks actually have the same rate as their parent (xo_board),
> so just return this rate.
> 
> Reported-by: Archit Taneja <architt@...eaurora.org>
> Fixes: 00f64b58874e ("clk: qcom: Add support for SMD-RPM Clocks")
> Signed-off-by: Georgi Djakov <georgi.djakov@...aro.org>
> ---
>  drivers/clk/qcom/clk-smd-rpm.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/clk/qcom/clk-smd-rpm.c b/drivers/clk/qcom/clk-smd-rpm.c
> index d990fe44aef3..b45782657ca9 100644
> --- a/drivers/clk/qcom/clk-smd-rpm.c
> +++ b/drivers/clk/qcom/clk-smd-rpm.c
> @@ -364,6 +364,10 @@ static unsigned long clk_smd_rpm_recalc_rate(struct clk_hw *hw,
>  {
>  	struct clk_smd_rpm *r = to_clk_smd_rpm(hw);
>  
> +	/* Return the parent rate for branches */
> +	if (r->branch)
> +		return parent_rate;
> +

What's parent_rate here though? 0? I don't see where we parent
the branch clks to anything.

And we should really just remove the recalc_rate() op for
branches entirely so that we don't have to call down into the
driver to find out something we could have known in the core.

-- 
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a Linux Foundation Collaborative Project