Re: [PATCH V4 2/2] pinctrl: tegra: Add driver to configure voltage and power of io pads

From: Jon Hunter
Date: Fri Nov 25 2016 - 12:36:02 EST



On 25/11/16 12:04, Laxman Dewangan wrote:
> Thanks Thierry for review.
>
> On Friday 25 November 2016 03:27 PM, Thierry Reding wrote:
>> * PGP Signed by an unknown key
>>
>> On Thu, Nov 24, 2016 at 02:08:54PM +0530, Laxman Dewangan wrote:
>>> + NVIDIA Tegra124/210 SoC has IO pads which supports multi-voltage
>>> + level of interfacing and deep power down mode of IO pads. The
>>> + voltage of IO pads are SW configurable based on IO rail of that
>>> + pads on T210. This driver provides the interface to change IO pad
>>> + voltage and power state via pincontrol interface.
>> This has a lot of chip-specific text. Will all of that have to be
>> updated if support for new chips is added?
>
> Then saying that Tegra124 and later..
> Hoping, people know our chip releasing sequence as numbering are not in
> sequence.
>
>>
>>> +#include <linux/regulator/consumer.h>
>>> +#include <soc/tegra/pmc.h>
>> Have you considered moving this code into the PMC driver? It seems a
>> little over the top to go through all of the platform device creation
>> and driver registration dance only to call into a public API later on.
>
> Yes, we had discussion on this and suggestion came to use the pinctrl
> framework.
> If we do in the pmc driver then we will need lots of DT processing for
> getting information from DT which we can directly get from the pinctrl
> core framework.
> Also client driver may need to have the control dynamically and get the
> IO pads from DT. So implementing all in pmc will be huge duplication
> over already existing framework.

I don't follow. We already did something similar for the Tegra DPAUX
driver [0].

Cheers
Jon

[0]
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/tegra/dpaux.c?id=0751bb5c44fe1aa9494ce259d974c3d249b73a84

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