| Message ID | 1418685929-13096-2-git-send-email-dianders@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Doug, On Mon, Dec 15, 2014 at 3:25 PM, Doug Anderson <dianders@chromium.org> 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@chromium.org> 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?
Andrew, On Mon, Dec 15, 2014 at 3:44 PM, Andrew Bresticker <abrestic@chromium.org> wrote: >> - 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? My thought was to purposely _not_ check the return value. The comment right above this says: * Program the voltage. Note that some instances of dw_mmc may use * the UHS_REG for this. For other instances (like exynos) the UHS_REG * does no harm but you need to set the regulator directly. Try both. ...I'm not 100% sure that I understand how the UHS_REG is supposed to be implemented since I've never seen a system that uses it. I was assuming that if you have UHS_REG you don't need the regulator... ...but probably a better solution is to return the error if " !IS_ERR(mmc->supply.vqmmc)". Let me fix that up and repost. -Doug
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 67c0451..4ae800c 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -1160,8 +1160,6 @@ static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios) struct dw_mci *host = slot->host; u32 uhs; u32 v18 = SDMMC_UHS_18V << slot->id; - int min_uv, max_uv; - int ret; /* * Program the voltage. Note that some instances of dw_mmc may use @@ -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); mci_writel(host, UHS_REG, uhs); return 0;
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@chromium.org> --- Changes in v2: None drivers/mmc/host/dw_mmc.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-)