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From: Ben Gardner on 24 Feb 2010 23:00
>> --- linux-2.6.33-rc8.orig/drivers/gpio/cs5535-gpio.c
>> +++ linux-2.6.33-rc8/drivers/gpio/cs5535-gpio.c
>> @@ -154,7 +154,7 @@
>>
>> �static int chip_gpio_get(struct gpio_chip *chip, unsigned offset)
>> �{
>> - � � return cs5535_gpio_isset(offset, GPIO_OUTPUT_VAL);
>> + � � return cs5535_gpio_isset(offset, GPIO_READ_BACK);
>> �}
>>
>> �static void chip_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
>
> <presses F10>
>
> What were the user-visible effects of this bug?

The user-visible effects were that the input didn't work.
I use the CS5535 chip in a custom board that uses GPIO 25 and 26 as
voltage monitoring inputs (external voltage comparators).
Since the char-based cs5535-gpio is now deprecated, I'm trying out the
gpio driver.
I export the GPIO pins via sysfs to access them from user-space.
Reading the 'value' member didn't reflect the input.

Personally, I would prefer a separate sysfs entry for the output and
the input, since the GPIO pins can be both outputs and inputs, but
that would require a gpiolib change.
Since there doesn't appear to be a gpio maintainer, any change to that
might be tricky.

Ben
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From: Ben Gardner on 24 Feb 2010 23:20
>> > What were the user-visible effects of this bug?
>>
>> The user-visible effects were that the input didn't work.
>> I use the CS5535 chip in a custom board that uses GPIO 25 and 26 as
>> voltage monitoring inputs (external voltage comparators).
>> Since the char-based cs5535-gpio is now deprecated, I'm trying out the
>> gpio driver.
>> I export the GPIO pins via sysfs to access them from user-space.
>> Reading the 'value' member didn't reflect the input.
>
> OK, then in that case we'd want to backport this into 2.6.33.x and
> perhaps earlier?

It looks like the driver was added 15 Dec 2009, so it doesn't look
like it existed in an earlier kernel.

>> Personally, I would prefer a separate sysfs entry for the output and
>> the input, since the GPIO pins can be both outputs and inputs, but
>> that would require a gpiolib change.
>> Since there doesn't appear to be a gpio maintainer, any change to that
>> might be tricky.
>
> Eh, we can cope. �Propose a patch and cc lots of people..

Will do.

Thanks,
Ben
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