Hi Fabio,
On Saturday, September 28, 2013 7:22:44 PM, Fabio Estevam wrote:
From: Fabio Estevam fabio.estevam@freescale.com
When the GPIO is configured as an output, we should return the value from the DR register.
This implements the same fix as in the following kernel commit from FSL BSP: http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/arch/arm/...
Why is this required? Is it because there is a different behavior of the PSR register on one of the i.MXs?
See my commit message here: http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=commitdiff;h=5dafa4543c...
In case the registers are configured to output some level on a GPIO but there is a level conflict with other hardware, the general assumption about gpio_get_value() would probably be that it returns the actual GPIO level, not the level that the registers try to apply. For the latter, another function accessing DR could be implemented.
One could also argue that such GPIO level conflicts are just the result of a flawed hardware design, and so that normal software should not care about such a case. But it's good to be able to detect hardware issues from software, and this patch seems to change the meaning of gpio_get_value() to cover some hardware issue. Please give more details.
In any case, there should probably be a comment in the code for this function to explain the various issues and how they are addressed.
Best regards, Benoît