[RFC PATCH] mmc: host: sdhci-iproc: implement the .hw_reset callback

[Meagan Lloyd]

On 4/15/2026 1:44 PM, Florian Fainelli wrote:
> On 4/15/26 13:43, Meagan Lloyd wrote:
>>
>> On 4/15/2026 1:23 PM, Scott Branden wrote:
>>> Hi Meagan,
>>>
>>> On Wed, Apr 15, 2026 at 11:08 AM Meagan Lloyd <
>>> meaganlloyd at linux.microsoft.com> wrote:
>>>
>>>> On 4/13/2026 10:43 AM, Florian Fainelli wrote:
>>>>> On 4/13/26 10:38, Meagan Lloyd wrote:
>>>>>> On 3/27/2026 3:21 PM, Meagan Lloyd wrote:
>>>>>>> Implement the .hw_reset callback so that the eMMC can be reset as
>>>>>>> needed
>>>>>>> given cap-mmc-hw-reset is set in the devicetree and the
>>>>>>> functionality is
>>>>>>> enabled on the eMMC.
>>>>>>>
>>>>>>> Signed-off-by: Meagan Lloyd <meaganlloyd at linux.microsoft.com>
>>>>>>> ---
>>>>>>>
>>>>>>> SDHCI_POWER_CONTROL[4] (SD Host Controller Standard) has been
>>>>>>> repurposed
>>>>>>> on my Broadcomm processor to be eMMC hardware reset
>>>>>>> (SDIO*_eMMCSDXC_CTRL[12], HRESET).
>>>>>>>
>>>>>>> Can you confirm this repurposed bit is consistent across the
>>>>>>> Broadcomm
>>>>>>> iProc processors and thus the .hw_reset callback can be uniformly
>>>>>>> applied in this driver?
>>>>>> Hi Ray & Scott,
>>>>>>
>>>>>> I hope you're doing well. This bit looks to have been repurposed
>>>>>> from
>>>>>> the SD Host Controller Standard's VDD2 Power Control to being
>>>>>> used for
>>>>>> toggling the hardware reset signal to eMMCs. Can you verify that it
>>>>>> applies across the iProc processors so that I may finalize this
>>>>>> patch?
>>>>> Which iProc process are you using? If you are not sure this applies
>>>>> broadly, can you at least make it specific to the SoC you are using?
>>>> Yes, if it comes to that I can. I think it's overkill to roll a new
>>>> compat string/associated structures over this small change, hence
>>>> checking with Broadcomm iProc maintainers on this thread.
>>>>
>>> Which iProc processor are you using?  You will have to check with
>>> RaspberryPI as I think they use this driver as well.
>>> If that family also supports it then you probably don't need a
>>> compatibility string.
>>
>> The processor I am using is the BCM58732. Can you help direct me to
>> someone who could comment from the RaspberryPi side?
>>
>
> I will take care of that. 
Thanks, Florian. Let me know what you find out :)