scsi: ufs: Fix regulator load and icc-level configuration

Currently if a regulator has "<name>-fixed-regulator" property in device
tree, it will skip current limit initialization.  This lead to a zero
"max_uA" value in struct ufs_vreg.

However, "regulator_set_load" operation shall be required on regulators
which have valid current limits, otherwise a zero "max_uA" set by
"regulator_set_load" may cause unexpected behavior when this regulator is
enabled or set as high power mode.

Similarly, in device's icc_level configuration flow, the target icc_level
shall be updated if regulator also has valid current limit, otherwise a
wrong icc_level will be calculated by zero "max_uA" and thus causes
unexpected results after it is written to device.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Acked-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -6294,19 +6294,19 @@ static u32 ufshcd_find_max_sup_active_icc_level(struct ufs_hba *hba,
 		goto out;
 	}
 
-	if (hba->vreg_info.vcc)
+	if (hba->vreg_info.vcc && hba->vreg_info.vcc->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vcc->max_uA,
 				POWER_DESC_MAX_ACTV_ICC_LVLS - 1,
 				&desc_buf[PWR_DESC_ACTIVE_LVLS_VCC_0]);
 
-	if (hba->vreg_info.vccq)
+	if (hba->vreg_info.vccq && hba->vreg_info.vccq->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vccq->max_uA,
 				icc_level,
 				&desc_buf[PWR_DESC_ACTIVE_LVLS_VCCQ_0]);
 
-	if (hba->vreg_info.vccq2)
+	if (hba->vreg_info.vccq2 && hba->vreg_info.vccq2->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vccq2->max_uA,
 				icc_level,
@@ -7004,6 +7004,15 @@ static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg,
 	if (!vreg)
 		return 0;
 
+	/*
+	 * "set_load" operation shall be required on those regulators
+	 * which specifically configured current limitation. Otherwise
+	 * zero max_uA may cause unexpected behavior when regulator is
+	 * enabled or set as high power mode.
+	 */
+	if (!vreg->max_uA)
+		return 0;
+
 	ret = regulator_set_load(vreg->reg, ua);
 	if (ret < 0) {
 		dev_err(dev, "%s: %s set load (ua=%d) failed, err=%d\n",