On 2019-11-18 15:15, Avri Altman wrote:
From: Can Guo <cang@xxxxxxxxxxxxxx>
Per UFS 3.0 JEDEC standard, the VCCQ2 min voltage is 1.7v and the VCCQ
voltage range is 1.14v ~ 1.26v. Update their hard codes accordingly to
make
sure they work in a safe range compliant for ver 1.0/2.0/2.1/3.0 UFS
devices.
So to keep it safe, we need to use largest range:
min_uV = min over all spec ranges, and max_uV = max over all spec
ranges.
Meaning leave it as it is if we want to be backward compatible with
UFS1.0.
Thanks,
Avri
Hi Avri,
Sorry I don't quite follow you here.
Leaving it as it is means for UFS2.1 devices, when boot up, if we call
regulator_set_voltage(1.65, 1.95) to setup its VCCQ2,
regulator_set_voltage() will
give you 1.65v on VCCQ2 if the voltage level of this regulator is wider,
say (1.60, 1.95).
Meaning you will finally set 1.65v to VCCQ2. But 1.65v is out of spec
for UFS v2.1 as it
requires min voltage to be 1.7v on VCCQ2. So, the smallest range is
safe.
Of course, in real board design, the regulator's voltage level is
limited/designed by power team
to be in a safe range, say (1.8, 1.92), so that calling
regulator_set_voltage(1.65, 1.95) still gives
you 1.8v. But it does not mean the current hard codes are compliant for
all UFS devices.
Best Regards,
Can Guo.
Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
---
drivers/scsi/ufs/ufs.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h index
385bac8..9df4f4d
100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -500,9 +500,9 @@ struct ufs_query_res {
#define UFS_VREG_VCC_MAX_UV 3600000 /* uV */
#define UFS_VREG_VCC_1P8_MIN_UV 1700000 /* uV */
#define UFS_VREG_VCC_1P8_MAX_UV 1950000 /* uV */
-#define UFS_VREG_VCCQ_MIN_UV 1100000 /* uV */
+#define UFS_VREG_VCCQ_MIN_UV 1140000 /* uV */
#define UFS_VREG_VCCQ_MAX_UV 1300000 /* uV */
-#define UFS_VREG_VCCQ2_MIN_UV 1650000 /* uV */
+#define UFS_VREG_VCCQ2_MIN_UV 1700000 /* uV */
#define UFS_VREG_VCCQ2_MAX_UV 1950000 /* uV */
/*
--
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