Re: [PATCH v3 06/12] soc: qcom: geni-se: Introduce helper APIs for performance control

[Konrad Dybcio]

On 2/20/26 6:23 AM, Praveen Talari wrote:
> Hi Konrad,
> 
> On 2/17/2026 5:55 PM, Konrad Dybcio wrote:
>> On 2/4/26 6:42 AM, Praveen Talari wrote:
>>> Hi Konrad,
>>>
>>> On 2/3/2026 4:44 PM, Konrad Dybcio wrote:
>>>> On 1/30/26 5:54 PM, Praveen Talari wrote:
>>>>> Hi Konrad
>>>>>
>>>>> On 1/30/2026 5:53 PM, Konrad Dybcio wrote:
>>>>>> On 1/12/26 11:47 AM, Praveen Talari wrote:
>>>>>>> The GENI Serial Engine (SE) drivers (I2C, SPI, and SERIAL) currently
>>>>>>> manage performance levels and operating points directly. This resulting
>>>>>>> in code duplication across drivers. such as configuring a specific level
>>>>>>> or find and apply an OPP based on a clock frequency.
>>>>>>>
>>>>>>> Introduce two new helper APIs, geni_se_set_perf_level() and
>>>>>>> geni_se_set_perf_opp(), addresses this issue by providing a streamlined
>>>>>>> method for the GENI Serial Engine (SE) drivers to find and set the OPP
>>>>>>> based on the desired performance level, thereby eliminating redundancy.
>>>>>>>
>>>>>>> Signed-off-by: Praveen Talari <praveen.talari@xxxxxxxxxxxxxxxx>
>>>>>>> ---
>>>>>>
>>>>>> [...]
>>>>>>
>>>>>>> +/**
>>>>>>> + * geni_se_set_perf_level() - Set performance level for GENI SE.
>>>>>>> + * @se: Pointer to the struct geni_se instance.
>>>>>>> + * @level: The desired performance level.
>>>>>>> + *
>>>>>>> + * Sets the performance level by directly calling dev_pm_opp_set_level
>>>>>>> + * on the performance device associated with the SE.
>>>>>>> + *
>>>>>>> + * Return: 0 on success, or a negative error code on failure.
>>>>>>> + */
>>>>>>> +int geni_se_set_perf_level(struct geni_se *se, unsigned long level)
>>>>>>> +{
>>>>>>> +    return dev_pm_opp_set_level(se->pd_list->pd_devs[DOMAIN_IDX_PERF], level);
>>>>>>> +}
>>>>>>> +EXPORT_SYMBOL_GPL(geni_se_set_perf_level);
>>>>>>
>>>>>> This function is never used
>>>>>
>>>>> it will be used by UART driver, not for I2C/SPI.
>>>>
>>>> Adding unused exported symbols is "eeeh"..
>>>
>>> I keep in mind for UART, i have added this API.
>>>>
>>>>>>
>>>>>>> +
>>>>>>> +/**
>>>>>>> + * geni_se_set_perf_opp() - Set performance OPP for GENI SE by frequency.
>>>>>>> + * @se: Pointer to the struct geni_se instance.
>>>>>>> + * @clk_freq: The requested clock frequency.
>>>>>>> + *
>>>>>>> + * Finds the nearest operating performance point (OPP) for the given
>>>>>>> + * clock frequency and applies it to the SE's performance device.
>>>>>>> + *
>>>>>>> + * Return: 0 on success, or a negative error code on failure.
>>>>>>> + */
>>>>>>> +int geni_se_set_perf_opp(struct geni_se *se, unsigned long clk_freq)
>>>>>>
>>>>>> I think with the SPI driver in mind (which seems to do a simple rateset
>>>>>
>>>>> APIs were added as generic interfaces shared across I²C/SPI which is specific to firmware control, not Linux control.
>>>>>
>>>>>> for both backends) we could do:
>>>>>>
>>>>>>> +{
>>>>>>> +    struct device *perf_dev = se->pd_list->pd_devs[DOMAIN_IDX_PERF];
>>>>>>
>>>>>> Then, we can do struct device * perf_dev = se->dev;
>>>>> I don't think, it is needed since this is specific to firmware control, not Linux control.
>>>>
>>>> My point is that it doesn't have to be specific to the auto usecase,
>>>> further commonizing the code.
>>>
>>> This API will not useful for non-auto cases as well.
>>
>> This is only because you make it so, with the above suggestion we could
>> do without the .set_rate abstraction in the SPI driver which only does
>> an opp_set_rate in the generic case
> 
> For the generic .set_rate path (which is managed by Linux), we do more than just call dev_pm_opp_set_rate().

I see, you're right. I glanced over this.

Konrad