From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCHv2 3/7] pinctrl: gpio: vt8500: Add pincontrol driver for arch-vt8500
Date: Wed, 27 Mar 2013 09:53:26 -0600 [thread overview]
Message-ID: <515315F6.5040401@wwwdotorg.org> (raw)
In-Reply-To: <1364376206.2160.10.camel@gitbox>
On 03/27/2013 03:23 AM, Tony Prisk wrote:
> On Tue, 2013-03-26 at 14:28 -0600, Stephen Warren wrote:
>> On 03/25/2013 12:51 PM, Tony Prisk wrote:
...
>>> - #gpio-cells : should be <3>.
>>> 1) bank
>>> 2) pin number
>>> 3) flags - should be 0
>>>
>>> I will clarify this in the next version.
>>
>> I think you should define a flag for inverted or active-low. This is
>> typically bit 0 in the flags cell.
>> ...
>
> Stephen,
>
> Do you know if there is an example of this somewhere I can look at?
>
> I did a quick search through the documentation for pinctrl and gpio, but
> I can't find any code for defining active-low in the gpio flags. There
> seems to be plenty for defining interrupt 'modes' but nothing for
> setting active-low.
Interrupt modes would be for the IRQ binding, not the GPIO binding.
For an example, see:
Documentation/devicetree/bindings/gpio/
> grep -i polarity *
> gpio-74x164.txt: the second cell is used to specify the gpio polarity:
> gpio-adnp.txt: - bit 0: polarity (0: normal, 1: inverted)
> gpio_lpc32xx.txt: - bit 0 specifies polarity (0 for normal, 1 for inverted)
> gpio-mxs.txt: the second cell is used to specify the gpio polarity:
> nvidia,tegra20-gpio.txt: - bit 0 specifies polarity (0 for normal, 1 for inverted)
> pl061-gpio.txt: - bit 0 specifies polarity (0 for normal, 1 for inverted)
> I also couldn't see anywhere where it was possible to interpret the
> flags that are passed in. Assuming I add an .of_xlate, and pass, for
> example, *flags = gpiospec[2] I can't see anywhere later on where I get
> the chance to 'decode' the flags to perform the specific configurations.
of_get_named_gpio_flags() will return the flags.
For an example usage, see:
> drivers/mmc/core/host.c:369: gpio = of_get_named_gpio_flags(np, "cd-gpios", 0, &flags);
(it's at that line in next-20130325 at least)
next prev parent reply other threads:[~2013-03-27 15:53 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-23 5:13 [PATCHv2 0/7] arm: vt8500: Add support for pinctrl/gpio module Tony Prisk
2013-03-23 5:13 ` [PATCHv2 1/7] of: Add support for reading a u32 from a multi-value property Tony Prisk
2013-04-15 10:12 ` Grant Likely
2013-03-23 5:13 ` [PATCHv2 2/7] arm: vt8500: Increase available GPIOs on arch-vt8500 Tony Prisk
2013-03-23 10:44 ` Russell King - ARM Linux
2013-03-23 18:04 ` Tony Prisk
2013-03-23 5:13 ` [PATCHv2 3/7] pinctrl: gpio: vt8500: Add pincontrol driver for arch-vt8500 Tony Prisk
2013-03-25 17:05 ` Stephen Warren
2013-03-25 18:51 ` Tony Prisk
2013-03-26 20:28 ` Stephen Warren
2013-03-27 4:59 ` Tony Prisk
2013-03-27 16:47 ` Stephen Warren
2013-03-27 9:23 ` Tony Prisk
2013-03-27 15:53 ` Stephen Warren [this message]
2013-03-28 5:03 ` Tony Prisk
2013-03-23 5:13 ` [PATCHv2 4/7] arm: dts: vt8500: Update Wondermedia SoC dtsi files for pinctrl driver Tony Prisk
2013-03-23 5:13 ` [PATCHv2 5/7] arm: vt8500: Remove gpio devicetree nodes Tony Prisk
2013-03-23 5:13 ` [PATCHv2 6/7] gpio: vt8500: Remove arch-vt8500 gpio driver Tony Prisk
2013-03-23 5:13 ` [PATCHv2 7/7] arm: vt8500: Remove pinmux configuration from mach-vt8500/vt8500.c Tony Prisk
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