From mboxrd@z Thu Jan 1 00:00:00 1970 From: vapier.adi@gmail.com (Mike Frysinger) Date: Sat, 22 Oct 2011 13:44:18 -0400 Subject: [PATCH] drivers: create a pin control subsystem v8 In-Reply-To: <20111004203520.GK2870@ponder.secretlab.ca> References: <1317211419-18472-1-git-send-email-linus.walleij@stericsson.com> <20110930020754.GK12606@ponder.secretlab.ca> <20111004203520.GK2870@ponder.secretlab.ca> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Oct 4, 2011 at 16:35, Grant Likely wrote: > On Sat, Oct 01, 2011 at 12:39:21PM +0200, Linus Walleij wrote: >> 2011/9/30 Grant Likely: >> >?I'm not convinced that the sysfs approach is >> > actually the right interface here (I'm certainly not a fan of the gpio >> > sysfs i/f), and I'd rather not be putting in unneeded stuff until the >> > userspace i/f is hammered out. >> >> Actually, thinking about it I cannot see what would be wrong >> with /dev/gpio0 & friends in the first place. >> >> Using sysfs as swiss army knife for custom I/O does not >> seem like it would be long-term viable so thanks for this >> observation, and I think we need /dev/gpio* put on some >> mental roadmap somewhere. > > Agreed. ?I don't want to be in the situation we are now with GPIO, > where every time I look at the sysfs interface I shudder. the problem with that is it doesn't scale. if i have a device with over 150 GPIOs on the SoC itself (obviously GPIO expanders can make that much bigger), i don't want to see 150+ device nodes in /dev/. that's a pretty big waste. sysfs only allocates/frees resources when userspace actually wants to utilize a GPIO. -mike