linux-kernel - Re: [BUG] mmc_regulator_set_ocr can't cope with regulator-fixed

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Message-ID: <20210805124650.GM26252@sirena.org.uk>
Date:   Thu, 5 Aug 2021 13:46:50 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Peter Geis <pgwipeout@...il.com>
Cc:     Jaehoon Chung <jh80.chung@...sung.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Rob Herring <robh+dt@...nel.org>, linux-mmc@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        devicetree@...r.kernel.org
Subject: Re: [BUG] mmc_regulator_set_ocr can't cope with regulator-fixed

On Thu, Aug 05, 2021 at 07:38:06AM -0400, Peter Geis wrote:

> Also, I've got a possible fix to the dw-mmc issue, the following patch
> changes the behavior to only enable a fixed regulator, not try to set
> the voltage. It's a split between the behavior when vmmc isn't defined
> at all and when its a variable regulator:

One thing to watch out for with this approach is if there's things that
really need a specific voltage to be set then you'll have to stop those
things happening if you've got a voltage regulator that can't deliver a
voltage in the required range.  I don't know if this affects MMC or not,
if it's just a case of being less efficient it's not such an issue.

> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index d333130d1531..b30102980261 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1446,11 +1446,13 @@ static void dw_mci_set_ios(struct mmc_host
> *mmc, struct mmc_ios *ios)
>   switch (ios->power_mode) {
>   case MMC_POWER_UP:
>   if (!IS_ERR(mmc->supply.vmmc)) {
> - ret = mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,

This patch is very whitespace damaged FWIW.

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