Thread (43 messages) 43 messages, 10 authors, 2013-03-01

[PATCH 3/5] gpio/omap: Add DT support to GPIO driver

From: Javier Martinez Canillas <hidden>
Date: 2013-02-27 20:00:13
Also in: linux-devicetree, linux-omap

On Wed, Feb 27, 2013 at 6:47 PM, Stephen Warren [off-list ref] wrote:
On 02/26/2013 08:33 PM, Javier Martinez Canillas wrote:
...
quoted
Yes, I realized that requesting the gpio was necessary so what I did
is to use the "regulator-fixed" optional property "gpio" and define
the GPIO used as an IRQ in a regulator used by the SMSC chip. So, I
have this on my board DT:

vddvario: regulator-vddvario {
      compatible = "regulator-fixed";
      regulator-name = "vddvario";
      regulator-always-on;
      gpio = <&gpio6 16 8>;  /* gpio line 176 */
      enable-active-high;
      gpio-open-drain;
While admittedly it's configured as open-drain, that will configure the
GPIO to be an output, whereas for usage as an interrupt, it really
should be configured as an input... Perhaps it makes no difference on
OMAP HW since the I/O paths are separate, but I can easily imagine HW
where this hack wouldn't work.
quoted
      regulator-boot-on;
};

&gpmc {
      ethernet at 5,0 {
              pinctrl-names = "default";
              pinctrl-0 = <&smsc911x_pins>;
              compatible = "smsc,lan9221", "smsc,lan9115";
              reg = <5 0 0xff>;
              interrupt-parent = <&gpio6>;
              interrupts = <16 8>; /* gpio line 176 */
              interrupt-names = "smsc911x irq";
              vmmc-supply = <&vddvario>;
              vmmc_aux-supply = <&vdd33a>;
              reg-io-width = <4>;

              smsc,save-mac-address;
      };
};

That way a call to gpio_request_one() is made and the GPIO is requested.

This look a little hack-ish for me but I've seen this in other
DeviceTrees like omap4-sdp.dts so I thought it was a common DT
pattern.
Indeed; the GPIO is in no way a regulator, so while the above is fine
for testing, it's in no way a solution that can actually be used and
checked in.
Yes, this is just a work-in-progress and is not meant to be taken as a
patch submission.

I'm just doing some testing with DT and figuring out how much effort
will take to have the same hardware support we currently with board
files for IGEP boards.

Thanks a lot for your feedback and best regards,
Javier
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