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From: Doug Anderson <dianders@chromium.org>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Taniya Das <tdas@codeaurora.org>
Subject: Re: [PATCH] clk: qcom: gcc-sdm845: Use floor ops for sdcc clks
Date: Fri, 30 Aug 2019 14:34:21 -0700
Message-ID: <CAD=FV=Vr5o-b86588qe--bVZ5YjKVB3gzaoYa6YcqCd9smkxVg@mail.gmail.com> (raw)
In-Reply-To: <20190830195142.103564-1-swboyd@chromium.org>

Hi,

On Fri, Aug 30, 2019 at 12:51 PM Stephen Boyd <swboyd@chromium.org> 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.


> Fixes: 06391eddb60a ("clk: qcom: Add Global Clock controller (GCC) driver for SDM845")
> Reported-by: Douglas Anderson <dianders@chromium.org>
> Cc: Taniya Das <tdas@codeaurora.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>
> 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@chromium.org>


-Doug

  reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-30 19:51 Stephen Boyd
2019-08-30 21:34 ` Doug Anderson [this message]
2019-09-03 15:52   ` Taniya Das
2019-09-03 22:47     ` Stephen Boyd
2019-09-05  9:22       ` Taniya Das
2019-09-09 10:25 ` Stephen Boyd

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