Tegra gpio driver: Need to configure pins in gpio mode/nontristate with gpio-request
ccross at google.com
Thu May 5 12:49:24 EDT 2011
On Thu, May 5, 2011 at 3:16 AM, Laxman Dewangan <ldewangan at nvidia.com> wrote:
> Hi All,
> When working on gpio driver for tegra, I found that gpio_request() does not
> make the corresponding soc pins to gpio mode. It still keeps the pins in SFIO mode.
> So we need to call two extra function along with gpio_request():
> Tegra_gpio_enable() and function for setting the pins in no non-tristate.
> Sue to this, the gpio sysfs interface does not work properly from user space /sys/class/gpio/.
> To make the pin in gpio mode fom user space, need to have changes in kernel.
> I think the gpio_request() should make the pins to gpio mode and make ready for use.
> Similarly gpio_free() should again put the pin into sfio mode with tristate disable.
> Please comment if there is any better way..
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