On 2019-11-19 20:41, Avri Altman wrote:
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.
You are correct - the narrowest the range the better - as long as you
don't cross the limits of previous spec.
So changing 1.1 -> 1.14 and 1.65 -> 1.7 is fine.
While at it, Vccq max in UFS3.0 is 1.26, why not change 1.3 -> 1.26,
like you indicated in your commit log?
Thanks,
Avri
Thank you Avri, sorry I missed the change to max voltage of VCCQ, I
will update it in the next version.
Best Regards,
Can Guo.
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 */
>>
>> /*
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum, a Linux Foundation Collaborative Project
