[RFC PATCH 0/7] gpiolib: add bias support

Ludovic Desroches ludovic.desroches at microchip.com
Thu Dec 14 22:54:16 PST 2017


Hi Andrew,

On Thu, Dec 14, 2017 at 05:06:25PM +0100, Andrew Lunn wrote:
> > I have not introduced a gpiod_set_bias() because I think the only place to
> > setup this is in the device tree. It's useless to setup a bias pull up if there
> > is an external pull up on the board.
> 
> Hi Ludovic
> 
> I have a use case where having gpiod_set_bias() would be good. The
> DLN2 is a USB device, which offers GPIO, I2C, and SPI services on its
> pins. It is a hot pluggable device, and i'm using it on Intel
> machines, making it double hard to use with Device Tree.
> 
> It would be good to be able to set the pull up/down on the GPIO pins,
> probably from a small kernel module which calls gpiod_set_bias(), or
> via /sysfs.

Thanks for your feedback. I'll try to keep your need in mind for next
version or rework.

Ludovic

> 
>     Andrew
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