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>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 81d99aebb8679a28467d7cfe19821460d0290d60..5ba49c8cd2a36e2c593a22810532e80059ec37c6 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/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",