Messages in this thread | | | From | Enric Balletbo Serra <> | Date | Wed, 26 Oct 2016 11:59:14 +0200 | Subject | Re: [PATCH] gpio: mcp23s08: Add option to configure pullups. |
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Hi Linus,
2016-10-24 8:13 GMT+02:00 Alexander Stein <alexander.stein@systec-electronic.com>: > On Monday 24 October 2016 02:53:31, Linus Walleij wrote: >> On Fri, Oct 21, 2016 at 5:00 PM, Enric Balletbo i Serra >> >> <enric.balletbo@collabora.com> wrote: >> > Default is without pullups, but if property is specified in DT and the bit >> > is set, set a pullup on GPIO-n. >> > >> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> >> >> I don't generally like this. >>
I tried to use the same approach as used in gpio-twl4030.c because is what I knew before. Maybe you can point me to a better approach?
>> In device tree it is the consumer that specifies how the line is used, >> not the producer (gpiochip). >> >> We currently only specify polarity, open drain and open source >> for consumers though. >> >> And the entire pin control system came into being *exactly* because >> Grant didn't like me adding these things to the GPIO drivers. >> >> So how many other things does the MCP support? Drive strength? >> Schmitt trigger? Is there a datasheet? > > Some unsupported features (AFAIK): > * Input polarity (IPOL register) > * open-drain interrupt pin > * pullup on pins (proposed patch) > > Datasheet is here: http://ww1.microchip.com/downloads/en/DeviceDoc/21919e.pdf > > Best regards, > Alexander > > -- > To unsubscribe from this list: send the line "unsubscribe linux-gpio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
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