* GPIO polarity in bindings for Freescale MXS
@ 2013-03-14 10:02 Hector Palacios
[not found] ` <5141A04D.8020805-i7dp0qKlBMg@public.gmane.org>
0 siblings, 1 reply; 4+ messages in thread
From: Hector Palacios @ 2013-03-14 10:02 UTC (permalink / raw)
To: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ
Hello,
Maybe I'm missing something but the MXS processors (at least i.MX23 and i.MX28) cannot
set the polarity of the GPIOs, so shouldn't the #gpio-cells be 1?
(From Documentation/devicetree/bindings/gpio/fsl-imx-gpio.txt):
- #gpio-cells : Should be two. The first cell is the pin number and
the second cell is used to specify the gpio polarity:
0 = active high
1 = active low
Regards,
--
Héctor Palacios
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: GPIO polarity in bindings for Freescale MXS
[not found] ` <5141A04D.8020805-i7dp0qKlBMg@public.gmane.org>
@ 2013-03-14 12:35 ` Hector Palacios
[not found] ` <5141C423.7030202-i7dp0qKlBMg@public.gmane.org>
2013-03-14 18:00 ` Stephen Warren
1 sibling, 1 reply; 4+ messages in thread
From: Hector Palacios @ 2013-03-14 12:35 UTC (permalink / raw)
To: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ
On 03/14/2013 11:02 AM, Hector Palacios wrote:
> Hello,
>
> Maybe I'm missing something but the MXS processors (at least i.MX23 and i.MX28) cannot
> set the polarity of the GPIOs, so shouldn't the #gpio-cells be 1?
>
> (From Documentation/devicetree/bindings/gpio/fsl-imx-gpio.txt):
Sorry, I meant: from Documentation/devicetree/bindings/gpio/gpio-mxs.txt
>
> - #gpio-cells : Should be two. The first cell is the pin number and
> the second cell is used to specify the gpio polarity:
> 0 = active high
> 1 = active low
>
> Regards,
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: GPIO polarity in bindings for Freescale MXS
[not found] ` <5141A04D.8020805-i7dp0qKlBMg@public.gmane.org>
2013-03-14 12:35 ` Hector Palacios
@ 2013-03-14 18:00 ` Stephen Warren
1 sibling, 0 replies; 4+ messages in thread
From: Stephen Warren @ 2013-03-14 18:00 UTC (permalink / raw)
To: Hector Palacios; +Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ
On 03/14/2013 04:02 AM, Hector Palacios wrote:
> Hello,
>
> Maybe I'm missing something but the MXS processors (at least i.MX23 and
> i.MX28) cannot set the polarity of the GPIOs, so shouldn't the
> #gpio-cells be 1?
>
> (From Documentation/devicetree/bindings/gpio/fsl-imx-gpio.txt):
>
> - #gpio-cells : Should be two. The first cell is the pin number and
> the second cell is used to specify the gpio polarity:
> 0 = active high
> 1 = active low
This field describes how software should interpret the GPIO values.
So, if the GPIO is specified as active-high, then software will
gpio_set_value(the_value_it_wants), whereas if the GPIO is specified as
active-low, then software will gpio_set_value(!the_value_it_wants). Note
that "software" here refers to the driver that requests/uses the GPIO,
and the flags can be retrieve using of_get_gpio_flags().
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: GPIO polarity in bindings for Freescale MXS
[not found] ` <5141C423.7030202-i7dp0qKlBMg@public.gmane.org>
@ 2013-03-15 5:24 ` Shawn Guo
0 siblings, 0 replies; 4+ messages in thread
From: Shawn Guo @ 2013-03-15 5:24 UTC (permalink / raw)
To: Hector Palacios; +Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ
On Thu, Mar 14, 2013 at 01:35:47PM +0100, Hector Palacios wrote:
> On 03/14/2013 11:02 AM, Hector Palacios wrote:
> >Hello,
> >
> >Maybe I'm missing something but the MXS processors (at least i.MX23 and i.MX28) cannot
> >set the polarity of the GPIOs, so shouldn't the #gpio-cells be 1?
> >
> >(From Documentation/devicetree/bindings/gpio/fsl-imx-gpio.txt):
>
> Sorry, I meant: from Documentation/devicetree/bindings/gpio/gpio-mxs.txt
>
> >
> >- #gpio-cells : Should be two. The first cell is the pin number and
> > the second cell is used to specify the gpio polarity:
> > 0 = active high
> > 1 = active low
The second cell is used by client devices to specify their gpio
connection polarity. Check of_get_named_gpio_flags() in
drivers/mmc/host/mxs-mmc.c for example to see how it's used.
Shawn
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-03-15 5:24 UTC | newest]
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2013-03-14 10:02 GPIO polarity in bindings for Freescale MXS Hector Palacios
[not found] ` <5141A04D.8020805-i7dp0qKlBMg@public.gmane.org>
2013-03-14 12:35 ` Hector Palacios
[not found] ` <5141C423.7030202-i7dp0qKlBMg@public.gmane.org>
2013-03-15 5:24 ` Shawn Guo
2013-03-14 18:00 ` Stephen Warren
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