mmc: sdio: Enable SDIO 4-bit bus if not support SD_SCR_BUS_WIDTH_4 for SD combo card

If the card type is SD combo(MMC_TYPE_SD_COMBO) and the memory part does
not support wider bus(SD_SCR_BUS_WIDTH_4), nothing will be done except
return 0. However, we should check whether IO part support wider bus or
not. We should use available IO ability if supported.

In addition, there's a duplicated check to MMC_CAP_4_BIT_DATA since
sdio_enable_wide() will include that check. And we can also save one
call site to sdio_enable_wide() after this change.
Signed-off-by: Yue Hu <huyue2@yulong.com>
Link: https://lore.kernel.org/r/20200608103009.5000-1-zbestahu@gmail.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/sdio.c

@@ -308,25 +308,23 @@ static int sdio_enable_4bit_bus(struct mmc_card *card)
 {
 	int err;
 
-	if (card->type == MMC_TYPE_SDIO)
-		err = sdio_enable_wide(card);
-	else if ((card->host->caps & MMC_CAP_4_BIT_DATA) &&
-		 (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
-		err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
-		if (err)
-			return err;
 	err = sdio_enable_wide(card);
 	if (err <= 0)
-			mmc_app_set_bus_width(card, MMC_BUS_WIDTH_1);
-	} else
-		return 0;
+		return err;
+	if (card->type == MMC_TYPE_SDIO)
+		goto out;
 
-	if (err > 0) {
-		mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
-		err = 0;
+	if (card->scr.bus_widths & SD_SCR_BUS_WIDTH_4) {
+		err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
+		if (err) {
+			sdio_disable_wide(card);
+			return err;
+		}
 	}
+out:
+	mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
 
-	return err;
+	return 0;
 }