On Thu, Jan 12, 2017 at 7:57 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > On 12 January 2017 at 05:43, Matt Ranostay <matt@ranostay.consulting> wrote: >> On Wed, Jan 11, 2017 at 2:55 PM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: >>> On 9 January 2017 at 05:53, Matt Ranostay <matt@ranostay.consulting> wrote: >>>> On Fri, Dec 30, 2016 at 12:05 AM, Linus Walleij >>>> <linus.walleij@xxxxxxxxxx> wrote: >>>>> On Mon, Dec 19, 2016 at 1:01 AM, Matt Ranostay <matt@ranostay.consulting> wrote: >>>>> >>>>>> * SD8787 has a "powerdown" line, and CW1200 has a "powerup" line.. I >>>>>> know this is a simple logic inversion. >>>>> >>>>> If this is a GPIO line, the GPIO subsystem can flag a line for >>>>> inverted logic. GPIO_ACTIVE_LOW from device tree for example. >>>> >>>> Slight ping on Ulf on this thread :). >>> >>> Thanks, sorry for the delay! >>> >>>> >>>> I do understand the inverted logic flag but that doesn't help if there >>>> are different logic states between various chipsets. >>> >>> For cw1200 (I looked at code from an old ST-Ericsson vendor tree), the >>> sequence is as follows: >>> >>> 1) Enable clock/power to the card/chip. >>> 2) Assert GPIO pin. I assume this also can be done before the >>> clock/power is enabled. >>> 3) Wait some time (~50ms). >>> 4) De-assert GPIO pin. >>> 5) Wait some time (~20ms) >>> 6) Assert GPIO pin. >>> 7) Wait some time (~32ms). >>> >>> At power off, the GPIO pin is de-asserted and of course also the >>> clock/power is disabled. Just to make sure we have all the relevant >>> logic. >>> >>> Looking at mmc pwrseq simple, perhaps we can extend this to deal with >>> GPIOs that needs to be *toggled*, as this is not just reset GPIOs. >>> Then we also need to deal with the delays in-between the toggling. >> >> Wouldn't we need to have a per chip function for each device >> supported? As well document gpios? I suspect we'd need an array of > > I was hoping to avoid this, but the more I look at it, it seems inevitable. > >> gpios defined in device tree since different devices will likely have >> various numbers of pins to toggle > > Maybe we can think of a clever way to combine cw1200 with your case? > Perhaps a "mmc pwrseq toggle". :-) If not, please go ahead an repost a > device specific mmc pwrseq for your case. I think the best solution for now. We can merge the two solutions latter down the road. Thanks, Matt > > I realize this would be a good opportunity for me to work on enabling > support for cw1200 on ux500, but as the implementation of the > clock/power control also needs to be up-streamed, I am quite far from > being done. > > 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
