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Subject[PATCH 4.4 156/241] scsi: ufs: Fix regulator load and icc-level configuration
Date
[ 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>
---
drivers/scsi/ufs/ufshcd.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c94d465de941e..ed76381fce4cc 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4144,19 +4144,19 @@ 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,
@@ -4390,6 +4390,15 @@ 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",
--
2.20.1


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