From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Daney Subject: Re: [PATCH RESEND] i2c: Add support for device-tree based chip initialization Date: Mon, 26 Nov 2012 16:26:39 -0800 Message-ID: <50B408BF.8050508@gmail.com> References: <1353905636-6697-1-git-send-email-linux@roeck-us.net> <20121126201346.4E8963E095F@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20121126201346.4E8963E095F@localhost> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely Cc: Guenter Roeck , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jean Delvare , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Ben Dooks , Wolfram Sang List-Id: devicetree@vger.kernel.org On 11/26/2012 12:13 PM, Grant Likely wrote: > On Sun, 25 Nov 2012 20:53:56 -0800, Guenter Roeck wrote: >> Some I2C devices are not or not correctly initialized by the firmware. >> Configuration would be possible via platform data, but that would require >> per-driver platform data and a lot of code, and changing it would not be >> possible without re-compiling the kernel. It is more elegant to do it >> generically via devicetree properties. >> >> Add a generic I2C devicetree property named "reg-init". This property provides >> a sequence of device initialization commands to be executed prior to calling >> the probe function for a given device. >> >> Signed-off-by: Guenter Roeck > > This is a very similar problem to the power sequences series that was > recently posted to this list. I would like that feature and this > mechanism use the same approach. I haven't fully studied the power sequencing thing, but just to play Devil's Advocate, there is precedence for the "reg-init" style in some of the Ethernet PHY drivers. Perhaps the "reg-init" should be used as one of the steps in the sequence, and if there was only a single step it would be functionally equivalent to the "reg-init" proposal. David Daney > > g. > > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org > https://lists.ozlabs.org/listinfo/devicetree-discuss > >