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SubjectRe: [PATCH v2] scsi: ufs: Remove pre-defined initial voltage values of device powers
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On 11/30/2020 10:51 PM, Stanley Chu wrote:
> UFS specficication allows different VCC configurations for UFS devices,
> for example,
> (1). 2.70V - 3.60V (Activated by default in UFS core driver)
> (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in
> device tree)
> (3). 2.40V - 2.70V (Supported since UFS 3.x)
>
> With the introduction of UFS 3.x products, an issue is happening that
> UFS driver will use wrong "min_uV-max_uV" values to configure the
> voltage of VCC regulator on UFU 3.x products with the configuration (3)
> used.
>
> To solve this issue, we simply remove pre-defined initial VCC voltage
> values in UFS core driver with below reasons,
>
> 1. UFS specifications do not define how to detect the VCC configuration
> supported by attached device.
>
> 2. Device tree already supports standard regulator properties.
>
> Therefore VCC voltage shall be defined correctly in device tree, and
> shall not changed by UFS driver. What UFS driver needs to do is simply
> enable or disable the VCC regulator only.
>
> Similar change is applied to VCCQ and VCCQ2 as well.
>
> Note that we keep struct ufs_vreg unchanged. This is allow vendors to
> configure proper min_uV and max_uV of any regulators to make
> regulator_set_voltage() works during regulator toggling flow.
> Without specific vendor configurations, min_uV and max_uV will be NULL
> by default and UFS core driver will enable or disable the regulator
> only without adjusting its voltage.
>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
> ---

Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>

> drivers/scsi/ufs/ufshcd-pltfrm.c | 16 ----------------
> 1 file changed, 16 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
> index a6f76399b3ae..09e2f04bf4f6 100644
> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> @@ -133,22 +133,6 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name,
> vreg->max_uA = 0;
> }
>
> - if (!strcmp(name, "vcc")) {
> - if (of_property_read_bool(np, "vcc-supply-1p8")) {
> - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV;
> - } else {
> - vreg->min_uV = UFS_VREG_VCC_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCC_MAX_UV;
> - }
> - } else if (!strcmp(name, "vccq")) {
> - vreg->min_uV = UFS_VREG_VCCQ_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCCQ_MAX_UV;
> - } else if (!strcmp(name, "vccq2")) {
> - vreg->min_uV = UFS_VREG_VCCQ2_MIN_UV;
> - vreg->max_uV = UFS_VREG_VCCQ2_MAX_UV;
> - }
> -
> goto out;
>
> out:
>


--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project

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