Re: [PATCH v2 2/3] mmc: dw_mmc: Use mmc_regulator_set_vqmmc in start_signal_voltage_switch

From: Andrew Bresticker
Date: Mon Dec 15 2014 - 18:44:30 EST


Hi Doug,

On Mon, Dec 15, 2014 at 3:25 PM, Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> We've introduced a new helper in the MMC core:
> mmc_regulator_set_vqmmc(). Let's use this in dw_mmc. Using this new
> helper has some advantages:
>
> 1. We get the mmc_regulator_set_vqmmc() behavior of trying to match
> VQMMC and VMMC when the signal voltage is 3.3V. This ensures max
> compatibility.
>
> 2. We get rid of a few more warnings when probing unsupported
> voltages.
>
> 3. We get rid of some non-dw_mmc specific code in dw_mmc.
>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>

One small comment below...

> @@ -1170,24 +1168,11 @@ static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios)
> */
> uhs = mci_readl(host, UHS_REG);
> if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
> - min_uv = 2700000;
> - max_uv = 3600000;
> uhs &= ~v18;
> } else {
> - min_uv = 1700000;
> - max_uv = 1950000;
> uhs |= v18;
> }
> - if (!IS_ERR(mmc->supply.vqmmc)) {
> - ret = regulator_set_voltage(mmc->supply.vqmmc, min_uv, max_uv);
> -
> - if (ret) {
> - dev_dbg(&mmc->class_dev,
> - "Regulator set error %d: %d - %d\n",
> - ret, min_uv, max_uv);
> - return ret;
> - }
> - }
> + mmc_regulator_set_vqmmc(mmc, ios);

Shouldn't we check the return value here and bail out of the voltage
switch procedure if it fails?
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