On Thu, Dec 19, 2013 at 06:18:40PM +0100, boris brezillon wrote: > Hello Felipe, > > On 19/12/2013 17:47, Felipe Balbi wrote: > >On Thu, Dec 19, 2013 at 08:41:09AM -0800, Greg Kroah-Hartman wrote: > >>On Thu, Dec 19, 2013 at 03:34:31PM +0100, Boris BREZILLON wrote: > >>>GPIO hogging is a way to request and configure specific GPIO without > >>>explicitly requesting it in the device driver. > >>> > >>>The request and configuration procedure is handled in the core device > >>>driver code before the driver probe function is called. > >>> > >>>It allows specific GPIOs to be configured without any driver specific code. > >>> > >>>Particularly usefull when a external device is connected to a bus and the > >>>bus connections depends on an external switch controlled by a GPIO pin. > >for external switches, you probably need a pinctrl-gpio driver. > > > Do you mean using pinctrl pinconf to configure the PIN as output-high or > output-low ? > > This was my first proposal > (see https://www.mail-archive.com/devicetree@xxxxxxxxxxxxxxx/msg05829.html). that's quite a weird argument from Linus W, considering you _do_ have a discrete mux on the board. We have quite a few of such "crazy" scenarios here at TI and we were going to send a pinctrl-gpio driver. If that's not acceptable, then I suppose there is no way to boot from NAND on a board where NAND signals go through a discrete mux where the select signal is a GPIO pin. -- balbi
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