From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] ARM: dts: am335x-bone* enable pmic-shutdown-controller Date: Mon, 18 May 2015 10:03:55 -0700 Message-ID: <20150518170354.GG10274@atomide.com> References: <1431525001-5747-1-git-send-email-robertcnelson@gmail.com> <20150513141658.GB6605@localhost> <20150513144846.GC6605@localhost> <20150518152108.GE10274@atomide.com> <20150518162936.GF10274@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Robert Nelson Cc: Matthijs van Duin , Johan Hovold , devicetree , "linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Felipe Balbi , pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org List-Id: devicetree@vger.kernel.org * Robert Nelson [150518 09:51]: > On Mon, May 18, 2015 at 11:29 AM, Tony Lindgren wrote: > > * Robert Nelson [150518 09:15]: > >> On Mon, May 18, 2015 at 10:21 AM, Tony Lindgren wrote: > >> > >> All the rev information is in the board's eeprom: > >> > >> hexdump -e '8/1 "%c"' /sys/bus/i2c/devices/0-0050/eeprom -s 12 -n 4 > >> > >> Rev A5B > >> 0A5B > >> > >> Rev C > >> 000C > >> > >> Just another default qwerk to add to Pantelis' bone_capemgr. ;) > > > > It seems we should not even instantiate some devices on BBB > > until the EEPROM is parsed.. So maybe something like this: > > > > 1. The problem devices are initially set with status = "disabled" > > in the dts > > > > 2. We set up drivers/*/bbb-eeprom.c that parses the board > > revision at module_init time, and then flips the selected > > devices to have status = "enabled" and populates the revision > > info based on the eeprom and SoC revision passed in pdata. > > Then those devices get their struct device created and > > probed, but at a much later time. > > > > So rather than trying to init all that early, let's just > > init them much later when we have the proper I2C driver > > running? > > I see that working just fine. We (beagleboard.org) enforce the eeprom > data, as all the official images require a proper baseboard eeprom. OK > We just have to be very careful to limit the scope, otherwise we will > end up with Pantelis' rejected capebus from the v3.2.x days... Naturally I was thinking #2 above would use Pantelis' code for CONFIG_OF_OVERLAY in mainline. But instead of the earlier patches, we can make things happen much later on to avoid the detect of EEPROM early on. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html