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 | Wed, 2 Sep 2015 13:49:53 +0530 |
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On Wednesday 02 September 2015 12:34 PM, Jisheng Zhang wrote: > On Wed, 2 Sep 2015 01:02:17 +0530 > Vaibhav Hiremath <vaibhav.hiremath@linaro.org> wrote: > >> Currently, the sdhci_do_start_signal_voltage_switch() function invokes >> controller specific voltage switch configuration only for 1.8v usecase; >> but it is required for others as well. >> >> For example, in case of PXA1928 SDH controller, we need to set different >> configuration for 3.3, 1.8 and 1.2 volt support (I/O domain power >> control register). >> >> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org> >> --- >> Note: >> Currently ->voltage_switch() callback is only supported >> in f_sdh30 driver. And I am not sure on the dependency of execution >> sequence for that device. I could have moved ->voltage_switch() call >> at one common place (above/below), but was not quite sure about it. >> So, replicated/duplicated the call for other voltages. >> >> drivers/mmc/host/sdhci.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >> index 3dd295f..b59b76d 100644 >> --- a/drivers/mmc/host/sdhci.c >> +++ b/drivers/mmc/host/sdhci.c >> @@ -1753,6 +1753,10 @@ static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host, >> /* Wait for 5ms */ >> usleep_range(5000, 5500); >> >> + /* Some controller need to do more when switching */ >> + if (host->ops->voltage_switch) >> + host->ops->voltage_switch(host, MMC_SIGNAL_VOLTAGE_330); > > 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.
Initially I was thinking of making use of pinconf framework, using PIN_CONFIG_POWER_SOURCE, but that too I am not sure is the right way of doing it.
Probably, question for pinctrl maintainer. Looping Linus Walleji.
Also note that, this configuration is not applicable to all pins/pads, only handpicked pads have this configuration (voltage selection on pads). And this configuration is not part of the same register map.
It is part of separate register map (AIB_EXT_REG_BASE), called IO domain power control register. And that
Thanks, Vaibhav
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