Re: [PATCH V1 1/2] scsi: ufs: ufs-qcom: Add specified gear support for multi gear scaling

[Manivannan Sadhasivam]

On Sat, Aug 29, 2026 at 01:13:54PM +0530, Nitin Rawat wrote:
> From: Ziqi Chen <ziqi.chen@xxxxxxxxxxxxxxxx>
> 
> The UFS clock frequency and gear speed do not necessarily have a strict
> one-to-one correspondence on all platforms. Introduce a device tree
> based configuration interface that allows specifying the HS gear
> speed for each supported operating frequency via the "opp-level"
> property in the OPP table. When this property is not configured, the
> driver falls back to the default frequency-to-gear mapping table.
> 
> Signed-off-by: Ziqi Chen <ziqi.chen@xxxxxxxxxxxxxxxx>
> Signed-off-by: Nitin Rawat <nitin.rawat@xxxxxxxxxxxxxxxx>
> ---
>  drivers/ufs/host/ufs-qcom.c | 30 ++++++++++++++++++++++++++----
>  1 file changed, 26 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index 0f2e083b04fd..aa2ac2cd2b69 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -2460,8 +2460,9 @@ static unsigned long ufs_qcom_opp_freq_to_clk_freq(struct ufs_hba *hba,
>  	bool found = false;
> 
>  	opp = dev_pm_opp_find_freq_exact_indexed(hba->dev, freq, 0, true);
> -	if (IS_ERR(opp)) {
> -		dev_err(hba->dev, "Failed to find OPP for exact frequency %lu\n", freq);
> +	if (IS_ERR_OR_NULL(opp)) {
> +		dev_err(hba->dev, "%s: Failed to find OPP for exact frequency %lu\n",
> +			__func__, freq);

Don't bring back the '__func__' marking please...

>  		return 0;
>  	}
> 
> @@ -2489,12 +2490,32 @@ static unsigned long ufs_qcom_opp_freq_to_clk_freq(struct ufs_hba *hba,
> 
>  static u32 ufs_qcom_freq_to_gear_speed(struct ufs_hba *hba, unsigned long freq)
>  {
> -	u32 gear = UFS_HS_DONT_CHANGE;
> +	struct dev_pm_opp *opp;
>  	unsigned long unipro_freq;
> +	u32 gear = UFS_HS_DONT_CHANGE;

Nit: Preserve reverse Xmas order.

> 
>  	if (!hba->use_pm_opp)
>  		return gear;
> 
> +	opp = dev_pm_opp_find_freq_exact_indexed(hba->dev, freq, 0, true);
> +	if (IS_ERR_OR_NULL(opp)) {
> +		dev_err(hba->dev, "%s: Failed to find OPP for exact frequency %lu\n",
> +			__func__, freq);

Drop '__func__' here and below.

> +		return gear;
> +	}
> +
> +	/* Get HS gear speed from 'opp-level' */
> +	gear = dev_pm_opp_get_level(opp);
> +	dev_pm_opp_put(opp);
> +
> +	/*
> +	 * Greater than max gear means that there is no specified gear configured in DT
> +	 * or the specified gear is invalid.
> +	 */
> +	if (gear <= hba->max_pwr_info.info.gear_rx)
> +		return gear;

Sashiko pointed out a valid concern with this check, please take a look.

- Mani

-- 
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