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

BugLink: https://bugs.launchpad.net/bugs/1837517
[ Upstream commit 0487fff76632ec023d394a05b82e87a971db8c03 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2ddf24466a62e39e351bd90e4f7d24edfad5791f..75d7267b73879bdf1841415665978bb13ac3f1bb 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6286,19 +6286,19 @@ 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,
@@ -7001,6 +7001,15 @@ 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",