On 9 December 2016 at 19:09, Rob Herring <robh@xxxxxxxxxx> wrote: > On Fri, Dec 02, 2016 at 01:06:47AM -0800, Matt Ranostay wrote: >> On Fri, Dec 2, 2016 at 12:28 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: >> > On 2 December 2016 at 08:22, Matt Ranostay <matt@ranostay.consulting> wrote: >> >> >> >> >> >>> On Dec 1, 2016, at 23:13, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: >> >>> >> >>>> On 2 December 2016 at 07:17, Matt Ranostay <matt@ranostay.consulting> wrote: >> >>>> Add optional device-post-power-on parameters to disable post_power_on >> >>>> function from being called since this breaks some device. >> >>>> >> >>>> Cc: Tony Lindgren <tony@xxxxxxxxxxx> >> >>>> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx> >> >>>> Signed-off-by: Matt Ranostay <matt@ranostay.consulting> >> >>>> --- >> >>>> Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt | 2 ++ >> >>>> drivers/mmc/core/pwrseq_simple.c | 7 +++++++ >> >>>> 2 files changed, 9 insertions(+) >> >>>> >> >>>> diff --git a/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt b/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt >> >>>> index bea306d772d1..09fa153f743e 100644 >> >>>> --- a/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt >> >>>> +++ b/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt >> >>>> @@ -24,6 +24,8 @@ Optional properties: >> >>>> de-asserting the reset-gpios (if any) >> >>>> - invert-off-state: Invert the power down state for the reset-gpios (if any) >> >>>> and pwrdn-gpios (if any) >> >>>> +- disable-post-power-on : Avoid post_power_on function from being called since >> >>>> + this breaks some devices >> >>> >> >>> This is a bit weird. I would like to avoid this, if possible. >> >>> >> >>> Perhaps if you simply describe the sequence in detail for your device >> >>> we can figure out the best option together. >> >> >> >> Yeah I know it is a bit weird but we need to keep that reset pin high for at least some time after pre power on. So any case it would be another property >> > >> > This went offlist, please resend. >> > >> > Moreover, please try to describe the sequence you need in detail >> > according to your HW spec. >> > >> >> Yeah oops.... >> >> So basically we need to drive the reset and powerdown lines high with >> a 300 milliseconds delay between both... >> can't have the reset line low with post power on (pretty sure but >> would need a delay anyway), and we need both reset + powerdown line >> set low on powerdown. >> >> So the power down sequence would need to be reversed for this >> application in pwrseq-simple. > > This sounds like you need a device specific sequence to me. Otherwise, > write a language to describe any power control waveforms rather than > trying to bolt on more and more properties. (Don't really go write a > language.) Actually this isn't so device specific. The cw1200 wifi chip which is being used with ux500 SoCs has a very similar sequence. Allow me to check the details and get back. Anyway, my point is that I think we can figure out a common sequence to support these kind required sequences. That is to me preferred over adding a new (two to support cw1200) device specific pwrseq driver. Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
