Re: [PATCH v5 00/10] clk: implement clock rate protection mechanism

From: Jerome Brunet
Date: Wed Dec 20 2017 - 12:45:18 EST


On Tue, 2017-12-19 at 16:38 -0800, Michael Turquette wrote:
> Applied to clk-protect-rate,

Thx !

> with the exception that I did not apply
> "clk: fix CLK_SET_RATE_GATE with clock rate protection" as it breaks
> qcom clk code.

Here is a reminder of what I found at the time (so you don't to dig in your
mailbox for it)

Regressions reported by Kci on the following platforms:
* qcom-apq8064-cm-qs600
* qcom-apq8064-ifc6410

it seems the problem is coming from the clock used by the mmc driver
(drivers/mmc/host/mmci.c)

the driver does following sequence:
* get_clk
* prepare_enable
* get_rate
* set_rate
* ...

with clock SDCx_clk (qcom_apq8064.dtsi:1037). This clock has CLK_SET_RATE_PARENT
flag so it will transmit the request to its parent.
The parent of this clock is SDCx_src which has the CLK_SET_RATE_GATE flag.

>
> Stephen, do you plan to fix up the qcom clock code so that the
> SET_RATE_GATE improvement can go in?
>
> Thanks,
> Mike