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SubjectRe: [PATCH v4 2/8] scsi: ufs: set load before setting voltage in regulators
Hi Can,
It makes sense that set the load before enable regulator or set
voltage. Just avoid voltage drop.

On 2020-01-23 15:25, Can Guo wrote:
> From: Asutosh Das <asutoshd@codeaurora.org>
>
> This sequence change is required to avoid dips in voltage
> during boot-up.
>
> Apparently, this dip is caused because in the original
> sequence, the regulators are initialized in lpm mode.
> And then when the load is set to high, and more current
> is drawn, than is allowed in lpm, the dip is seen.
>
> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---
> drivers/scsi/ufs/ufshcd.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index c2de29f..c386c2d 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -7225,6 +7225,11 @@ static int ufshcd_config_vreg(struct device
> *dev,
> name = vreg->name;
>
> if (regulator_count_voltages(reg) > 0) {
> + uA_load = on ? vreg->max_uA : 0;
> + ret = ufshcd_config_vreg_load(dev, vreg, uA_load);
> + if (ret)
> + goto out;
> +
> if (vreg->min_uV && vreg->max_uV) {
> min_uV = on ? vreg->min_uV : 0;
> ret = regulator_set_voltage(reg, min_uV, vreg->max_uV);
> @@ -7235,11 +7240,6 @@ static int ufshcd_config_vreg(struct device
> *dev,
> goto out;
> }
> }
> -
> - uA_load = on ? vreg->max_uA : 0;
> - ret = ufshcd_config_vreg_load(dev, vreg, uA_load);
> - if (ret)
> - goto out;
> }
> out:
> return ret;


Reviewed-by: Hongwu Su <hongwus@codeaurora.org>

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