Re: [PATCH] clk: qcom: gcc-sdm845: Use floor ops for sdcc clks

[Taniya Das]

Hi,

On 8/31/2019 3:04 AM, Doug Anderson wrote:
> Hi,
>
> On Fri, Aug 30, 2019 at 12:51 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:
> > Some MMC cards fail to enumerate properly when inserted into an MMC slot
> > on sdm845 devices. This is because the clk ops for qcom clks round the
> > frequency up to the nearest rate instead of down to the nearest rate.
> > For example, the MMC driver requests a frequency of 52MHz from
> > clk_set_rate() but the qcom implementation for these clks rounds 52MHz
> > up to the next supported frequency of 100MHz. The MMC driver could be
> > modified to request clk rate ranges but for now we can fix this in the
> > clk driver by changing the rounding policy for this clk to be round down
> > instead of round up.
>
> Since all the MMC rates are expressed as "maximum" clock rates doing
> it like you are doing it now seems sane.

Looks like we need to update/track it for all SDCC clocks for all targets.


> > Fixes: 06391eddb60a ("clk: qcom: Add Global Clock controller (GCC) driver for SDM845")
> > Reported-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> > Cc: Taniya Das <tdas@xxxxxxxxxxxxxx>
> > Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> > ---
> >
> > I suppose we need to do this for all the sdc clks in qcom driver?
>
> Seems like a good idea to me.
>
>
> >   drivers/clk/qcom/gcc-sdm845.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
>
> Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
>
>
> -Doug

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