Messages in this thread | | | Subject | Re: [RFC 2/3] mmc: sdhci: add host_ops->voltage_switch callback for all other voltages | From | Vaibhav Hiremath <> | Date | Mon, 14 Sep 2015 18:17:03 +0530 |
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On Monday 14 September 2015 06:11 PM, Vaibhav Hiremath wrote: > > > On Monday 14 September 2015 04:04 PM, Ulf Hansson wrote: >> On 14 September 2015 at 11:42, Vaibhav Hiremath >> <vaibhav.hiremath@linaro.org> wrote: >>> >>> >>> On Monday 14 September 2015 03:00 PM, Ulf Hansson wrote: >>>> >>>> [...] >>>> >>>>>>>> >>>>>>>> Could this be implemented by regulator API? From patch set 3/3, the >>>>>>>> pxa1928 >>>>>>>> voltage_switch hook is to operate the IO pad registers, this >>>>>>>> seems not >>>>>>>> belong >>>>>>>> to the SDHC IP core. >>>>>>>> >>>>>>> >>>>>>> Not quite sure whether regulator would be right fit for this. >>>>>> >>>>>> >>>>>> >>>>>> From the patche[3/3], this can be achieved by abstracting the >>>>>> IO PAD >>>>>> as >>>>>> regulators >>>>>> then, we may not need to touch the core sdhci.c. But I'm not sure >>>>>> whether >>>>>> this >>>>>> is the good solution or not. >>>>> >>>>> >>>>> >>>>> Exactly... >>>>> >>>>>> sdhci Maintainers and experts may have better >>>>>> suggestions. >>>>>> >>>>> >>>>> Thats is the reason I stamped it as a RFC :) >>>>> >>>> >>>> [...] >>>> >>>> From an mmc core perspective it would be preferred if you implement >>>> this as a regulator (vqmmc). >>>> >>>> Especially since we will soon have an API for how to set the I/O >>>> voltages - and the intelligence within that API is not something we >>>> would like to implement for each and every host driver. >>>> https://lkml.org/lkml/2015/8/31/367 >>>> >>> >>> >>> I would still consider this as a regulator specific and may not address >>> the IO configuration within the SoC which are module specific. >>> The API regulator_set_voltage_triplet() will not have intelligence to >>> differentiate whether the call is coming from MMC or somewhere else. >>> >>> Note that, the IO pad voltage configuration which I am referring to is >>> MMC specific and applicable only when pad is configured in MMC mode. So >>> technically it is not simply common pad voltage configuration. >>> >>> >>> And I am still not sure regulator framework would be right fit for >>> this. Pinctrl would have been right fit, but...since I saw f_sdh30 >>> driver is already doing this, which is easy fit; so adopted the same. >> >> Pinctrl would work as well, or perhaps a combination of both pinctrl >> and a regulator. > > > Not sure, how I can propagate "call coming from MMC/SD" to both > regulator and pinctrl. > Probably pinctrl would already know, but then it doesn't know the > voltage settings. > > Let me spend some time, but atleast at this point I am not sure. > >>
On the side note, Lets park this patch aside, till I get back with better option.
It would be nice if you could review other patches, let them notget blocked due to this.
Thanks, Vaibhav
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