Re: [PATCH v3 1/3] mmc: core: Add mmc_regulator_set_vqmmc()
From: Doug Anderson
Date: Wed Feb 25 2015 - 15:23:48 EST
Ulf,
On Mon, Dec 15, 2014 at 4:22 PM, Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> This adds logic to the MMC core to set VQMMC. This is expected to be
> called by MMC drivers like dw_mmc as part of (or instead of) their
> start_signal_voltage_switch() callback.
>
> A few notes:
>
> * When setting the signal voltage to 3.3V we do our best to make VQMMC
> and VMMC match. It's been reported that this makes some old cards
> happy since they were tested back in the day before UHS when VQMMC
> and VMMC were provided by the same regulator. A nice side effect of
> this is that we don't end up on the hairy edge of VQMMC (2.7V),
> which some EEs claim is a little too close to the minimum for
> comfort.
>
> * When setting the signal voltage to 1.8V or 1.2V we aim for that
> specific voltage instead of picking the lowest one in the range.
>
> * We very purposely don't print errors in mmc_regulator_set_vqmmc().
> There are cases where the MMC core will try several different
> voltages and we don't want to pollute the logs.
>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> Reviewed-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
> ---
> Changes in v3: None
> Changes in v2:
> - Now use existing regulator_set_voltage_tol() function.
>
> drivers/mmc/core/core.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/mmc/host.h | 7 +++++++
> 2 files changed, 58 insertions(+)
Do you know the status of this patch and its partner patch (mmc:
dw_mmc: Use mmc_regulator_set_vqmmc in start_signal_voltage_switch -
https://patchwork.kernel.org/patch/5498551/)?
I'm happy to repost them or address feedback.
Thanks! :)
-Doug
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