On Wed, Dec 14, 2016 at 5:46 PM, Matt Ranostay <matt@ranostay.consulting> wrote: > On Tue, Dec 13, 2016 at 12:01 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: >> 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. > > Ok. It would be good to have something common than a bunch of one-off > solutions for sure. > >> >> 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. >> So briefly looked at the cw1200 driver (I'm guessing the datasheet is NDA since I couldn't find it) and it seems like it would be a good fit to have a common pwrseq driver. So minor things I noticed that the cw1200 device has different from our SD8787 chipset. * SD8787 has a "powerdown" line, and CW1200 has a "powerup" line.. I know this is a simple logic inversion. * CW1200 has a clock control line, that seems to be asserted between the powerup/reset steps. Would there need to be some per driver functions that could be registered for edge cases like this? >> 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
