Stefan Roese wrote:
> On Saturday 12 January 2008, Sean MacLennan wrote:
>
>> Josh Boyer wrote:
>>
>>>> + if (gpio_base == NULL) {
>>>> + printk("ERROR: Unable to remap GPIO base.\n");
>>>> + return;
>>>> + }
>>>> + }
>>>> +
>>>> + leds = readl(gpio_base + 0x100);
>>>>
>>> Do you really want readl here? That will byte-swap.
>>>
>> According to the docs I got from the hardware guys, this is correct.
>> That does *not* mean they didn't get it wrong. Unfortunately, it was
>> just on a piece of paper and I don't know if I still have it.
>>
>
> You are accessing the 440EP GPIO controller here right? Then you really
> should
> use big endian access routines. From you code I assume that you have
> connected the LED signals to GPIO00 and GPIO01. I suggest to use code that
> looks like this:
>
> #define LED_GREEN (0x80000000 >> 0)
> #define LED_RED (0x80000000 >> 1)
>
> leds = in_be32(gpio_base);
>
> switch (green) {
> case 0: leds &= ~LED_GREEN; break;
> case 1: leds |= LED_GREEN; break;
> }
> switch (red) {
> case 0: leds &= ~LED_RED; break;
> case 1: leds |= LED_RED; break;
> }
>
> outbe32(leds, gpio_base);
>
> And when you change the dts to describe both GPIO controllers you should map
> the 2nd one and remove the 0x100 offset above as I have done above.
>
> Best regards,
> Stefan
>
Ok. I will look into that. What is the best practice for looking up the
second GPIO controller? I have been using of_find_compatible_type. I
could call it a second time with a from arg.
Cheers,
Sean
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