From mboxrd@z Thu Jan 1 00:00:00 1970 From: eric@anholt.net (Eric Anholt) Date: Mon, 06 Jun 2016 16:50:31 -0700 Subject: [PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander. In-Reply-To: <1464817421-8519-28-git-send-email-kraxel@redhat.com> References: <1464817421-8519-1-git-send-email-kraxel@redhat.com> <1464817421-8519-28-git-send-email-kraxel@redhat.com> Message-ID: <87port98s8.fsf@eliezer.anholt.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Gerd Hoffmann writes: > From: Eric Anholt > > This commit needs to be split up and cleaned up. Also we should add > interrupt support before pushing upstream. > > Signed-off-by: Eric Anholt OK, I've confirmed with the firmware maintainers: We really can't drive this natively from Linux. The firmware is polling one of the fxl6408's pins 10 times a second for detecting under-voltage, so if we also try to drive it we'll end up smashing each others' I2C transactions. We'll need to do a GPIO driver using the GET/SET_GPIO_STATE firmware calls, instead. Unfortunately, we don't have a direction-setting API for that at the moment, but it'll at least let us read the HDMI HPD signal. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 818 bytes Desc: not available URL: