Hello, On Wed, Aug 24, 2016 at 02:45:17PM +0530, Vignesh R wrote: > On Wednesday 24 August 2016 02:05 PM, Daniel Mack wrote: > > On 08/24/2016 09:58 AM, Vignesh R wrote: > >> This series adds support for rotary-switch on AM335x-ICE that is > >> connected to TI PCA9536 I2C GPIO expander. > >> First patch adds new generic driver to read status of group of GPIO > >> lines and report the value as an input event. The second patch adds DT > >> entries for the same. > >> > >> v2: https://lkml.org/lkml/2016/8/23/111 > >> v1: https://lkml.org/lkml/2016/8/12/7 > > > > Is there a reason why the rotary-encoder driver cannot handle this? > > Commit 7dde4e74744 ("Input: rotary-encoder - support more than 2 gpios > > as input") added support for that mode AFAIU. > > > > Rotary encoder driver handles incremental encoders only and does not > support absolute encoders. The rotary switch on am335x-ice is different > from the incremental encoders in the > sense that GPIO line status directly reflect the position(number) > pointed by the dial of the encoder. So, there is no need to count steps > or know the direction of rotation as it does not matter. I'd still prefer to expand drivers/input/misc/rotary_encoder.c to handle this. Yes, there is no reason to count steps or determine the direction of a rotation in this case, but still there is much code to share and IMHO it's ok that a driver that handles several types of similar devices does too much for some special cases. > I did try to enhance rotary-encoder driver to support absolute > encoder[1] but the comment there was to write new driver that simply > translates gpio-encoded value into ABS* event. Indeed, the new driver > looks more simple and can handle more such hardwares. Which type of hardware can be handled by your driver that the generic rotary encoder cannot? I guess it's just a matter of a (simple) patch? Best regards Uwe > [1] https://lkml.org/lkml/2016/5/19/98 -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
