Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1265487

Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc supply

Show all headers | View raw

[...]

>> > Is the regulator-gpio usage the right thing to do for vqmmc? In my case it is
>> > not really driven by a gpio but by a pio from the sdhci device. In the binding,
>>
>> What's a "pio"?
>>
>> What do you mean by the it's driven from the sdhci device?
>>
>
> Sorry I mean sdhci device from the SoC point of view, I should say
> controller. So yes the signal is driven by the controller.
>
>> Is it the internal HW logic of the sdhci controller that manages the
>> IO voltage? And this logic can be controlled via certain register bits
>> in the SDHCI controller?
>>
>
> Yes, it depends of the value of the '1.8V Signaling Enable' value in the
> host control 2 register.
>
>> > declaring the gpio is an option so I thought using this regulator fits my need.
>>
>> In quite many cases it makes sense to model this though a gpio
>> regulator. For example when you use a level shifter circuit. Those
>> normally have gpio pin routed to control the voltage level output for
>> the signals. For example switching between 1.8V and 2.9V.
>>
>
> I agree, my concern is to know if I can consider it as a 'general' pio
> since it is driven by the sdhci controller.

This doesn't seems like a case where a gpio regulator should be used
and I am not sure what problem it would solve. Beside to suppress the
log warnings (actually those aren't warnings but informations).

Isn't sdhci_do_start_signal_voltage_switch() doing what you need here?

Kind regards
Uffe
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc supply Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-06 17:00 +0100
  [PATCH 1/2] mmc: sdhci: set bus voltage before enabling bus power Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-06 17:10 +0100
    Re: [PATCH 1/2] mmc: sdhci: set bus voltage before enabling bus power Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-09 14:30 +0100
      Re: [PATCH 1/2] mmc: sdhci: set bus voltage before enabling bus power Ulf Hansson <ulf.hansson@linaro.org> - 2015-11-09 15:20 +0100
        Re: [PATCH 1/2] mmc: sdhci: set bus voltage before enabling bus power Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-09 15:50 +0100
          Re: [PATCH 1/2] mmc: sdhci: set bus voltage before enabling bus power Ulf Hansson <ulf.hansson@linaro.org> - 2015-11-09 17:10 +0100
            Re: [PATCH 1/2] mmc: sdhci: set bus voltage before enabling bus power Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-09 17:40 +0100
  [PATCH 2/2] ARM: at91/dt: sama5d2 Xplained: add regulators for sdhci devices Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-06 17:10 +0100
  Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc supply Ulf Hansson <ulf.hansson@linaro.org> - 2015-11-06 17:50 +0100
    Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc  supply Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-09 08:50 +0100
      Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc supply Ulf Hansson <ulf.hansson@linaro.org> - 2015-11-09 10:40 +0100
        Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc  supply Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-09 11:30 +0100
          Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc supply Ulf Hansson <ulf.hansson@linaro.org> - 2015-11-09 12:00 +0100
            Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc  supply Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-09 14:20 +0100
              Re: [PATCH 0/2] mmc: sdhci: potentially bad behavior when using vmmc supply Ulf Hansson <ulf.hansson@linaro.org> - 2015-11-09 14:20 +0100

csiph-web