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

[Javier Martinez Canillas]

On Wed, Feb 27, 2013 at 12:08 AM, Jon Hunter <jon-hunter at ti.com> wrote:
>
> On 02/26/2013 04:01 AM, Javier Martinez Canillas wrote:
>
> [snip]
>
>> I was wondering if the level/edge settings for gpios is working on OMAP.
>>
>> I'm adding DT support for an SMSC911x ethernet chip connected to the
>> GPMC for an OMAP3 SoC based board.
>>
>> In the smsc911x driver probe function (smsc911x_drv_probe() in
>> drivers/net/ethernet/smsc/smsc911x.c), a call to request_irq() with
>> the flag IRQF_TRIGGER_LOW is needed because of the wiring on my board.
>>
>> Reading the gpio-omap.txt documentation it says that #interrupt-cells
>> should be <2> and that a value of 8 is "active low level-sensitive".
>>
>> So I tried this:
>>
>> &gpmc {
>>       ethernet at 5,0 {
>>               pinctrl-names = "default";
>>               pinctrl-0 = <&smsc911x_pins>;
>>               compatible = "smsc,lan9221", "smsc,lan9115";
>>               reg = <5 0 0xff>; /* CS5 */
>>               interrupt-parent = <&gpio6>;
>>               interrupts = <16 8>; /* gpio line 176 */
>>               interrupt-names = "smsc911x irq";
>>               vmmc-supply = <&vddvario>;
>>               vmmc_aux-supply = <&vdd33a>;
>>               reg-io-width = <4>;
>
> By the way, reg-io-width for omap does not look correct. The GPMC only
> supports 8-bit or 16-bit devices IIRC. I believe all my omap boards use
> 16-bit.
>

I thought that even when the GPMC was a 16-bit external memory
controller it could do some access adaptation to support 32-bit
devices.

By looking at the board files for others OMAP3 based boards
(board-{omap3evm,overo,zoom-debugboard}.c) most of them set the struct
omap_smsc911x_platform_data .flags member to SMSC911X_USE_32BIT.

And by looking at Documentation/devicetree/bindings/net/smsc911x.txt I
thought that the corresponding DT property for this flag was
"reg-io-width"

Anyway, I tried using both reg-io-width = <4> and reg-io-width = <2>.
The ethernet chip works with both of them and I don't see too much
difference in performance:

16-bit
round-trip min/avg/max = 0.611/0.738/0.946 ms

32-bit
round-trip min/avg/max = 0.519/0.690/0.976 ms

So, is your call ;-)

> Cheers
> Jon

Thanks a lot for your help,
Javier