Messages in this thread | | | Date | Mon, 14 Dec 2009 22:40:19 -0800 | Subject | Re: GPIO support for HTC Dream | From | Arve Hjønnevåg <> |
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On Mon, Dec 14, 2009 at 10:12 AM, H Hartley Sweeten <hartleys@visionengravers.com> wrote: > On Monday, December 14, 2009 10:55 AM, Daniel Walker wrote: >> On Mon, 2009-12-14 at 07:45 +0100, Pavel Machek wrote: >>> Hi! >>> >>>> This looks MUCH better! >>> >>> Thanks :-). >>> >>>>> arch/arm/Kconfig | 1 >>>>> arch/arm/mach-msm/board-dream-gpio.c | 327 +++++++++-------------------------- >>> ... >>>> Please update (or remove) this diffstat. It no longer matches the patch. >>> >>> I was just showing differences to _previous_ version, not what I was sending. >>> >>>> Ok. The hardware still seems a bit strange. Is there any datasheet >>>> available? >>> >>> I don't think there is one. Daniel, can you help here? >> >> I don't know if there is one or not (I'd guess not).. I can't release >> documents, but I could try to address specific questions or find people >> to answer specific questions. > > Hello Daniel, > > My specific question was about the gpio hardware registers. > > From Pavel's implementation it appears that the gpio's are organized as a > number of 8-bit ports. Each of these ports only have one 8-bit register. > Writing a '1' to a bit in the register makes the associated pin a high-level > output. Writing a '0' makes the pin a low-level output or an input pin. > Reading the port at this point will return the actual 'input' level of the pin. > > The hardware seems a bit strange and I just wanted to verify that this is > correct. If it is, this would explain the need to keep the 'shadow' contents > of the port in order to set the 'direction' of a pin. > > I was also wondering if the initial 'shadow' value needs to be written to the > port at init in order to correctly establish the output value for specific > pins. > > One other thing. Are the gpio's handled by Pavel's driver actually from the > MSM chip or from an external CPLD? The registers are all defined as: > > + .reg = reg_num + DREAM_CPLD_BASE, > > If they are external from the MSM chip this driver should probably be renamed > to something more appropriate since it is probably dream specific and not > generic to the msm architecture.
These are board specific gpios. I think it would be less confusing if the msm gpio support was added first.
-- Arve Hjønnevåg -- 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/
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