On 2020-09-15 06:37, Bjorn Andersson wrote:
On Tue 15 Sep 03:49 CDT 2020, nguyenb@xxxxxxxxxxxxxx wrote:
On 2020-09-14 19:54, Bjorn Andersson wrote:
> On Tue 01 Sep 01:19 UTC 2020, Bao D. Nguyen wrote:
>
> > UFS version 3.0 and later devices require Vcc and Vccq power supplies
> > with Vccq2 being optional. While earlier UFS version 2.0 and 2.1
> > devices, the Vcc and Vccq2 are required with Vccq being optional.
> > Check the required power supplies used by the device
> > and set the device's supported Icc level properly.
> >
> > Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> > Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
> > Signed-off-by: Bao D. Nguyen <nguyenb@xxxxxxxxxxxxxx>
> > ---
> > drivers/scsi/ufs/ufshcd.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index 06e2439..fdd1d3e 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -6845,8 +6845,9 @@ static u32
> > ufshcd_find_max_sup_active_icc_level(struct ufs_hba *hba,
> > {
> > u32 icc_level = 0;
> >
> > - if (!hba->vreg_info.vcc || !hba->vreg_info.vccq ||
> > - !hba->vreg_info.vccq2) {
> > + if (!hba->vreg_info.vcc ||
>
> How did you test this?
>
> devm_regulator_get() never returns NULL, so afaict this conditional will
> never be taken with either the old or new version of the code.
Thanks for your comment. The call flow is as follows:
ufshcd_pltfrm_init->ufshcd_parse_regulator_info->ufshcd_populate_vreg
In the ufshcd_populate_vreg() function, it looks for DT entries
"%s-supply"
For UFS3.0+ devices, "vccq2-supply" is optional, so the vendor may
choose
not to provide vccq2-supply in the DT.
As a result, a NULL is returned to hba->vreg_info.vccq2.
Same for UFS2.0 and UFS2.1 devices, a NULL may be returned to
hba->vreg_info.vccq if vccq-supply is not provided in the DT.
The current code only checks for !hba->vreg_info.vccq OR
!hba->vreg_info.vccq2. It will skip the setting for icc_level
if either vccq or vccq2 is not provided in the DT.
>
Thanks for the pointers, I now see that the there will only be struct
ufs_vreg objects allocated for the items that has an associated
%s-supply.
FYI, the idiomatic way to handle optional regulators is to use
regulator_get_optional(), which will return -ENODEV for regulators not
specified.
Thanks for the regulator_get_optional() suggestion. Do you have a strong
opinion about
using regulator_get_optional() or would my proposal be ok? With
regulator_get_optional(),
we need to make 3 calls and check each result while the current
implementation is also reliable
simple quick check for NULL without any potential problem.
Thanks,
Bao
Regards,
Bjorn
> Regards,
> Bjorn
>
> > + (!hba->vreg_info.vccq && hba->dev_info.wspecversion >= 0x300) ||
> > + (!hba->vreg_info.vccq2 && hba->dev_info.wspecversion < 0x300)) {
> > dev_err(hba->dev,
> > "%s: Regulator capability was not set, actvIccLevel=%d",
> > __func__, icc_level);
> > --
> > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> > Forum,
> > a Linux Foundation Collaborative Project
> >
