On 11/26/2012 12:13 PM, Grant Likely wrote:
On Sun, 25 Nov 2012 20:53:56 -0800, Guenter Roeck <linux@xxxxxxxxxxxx> 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 <linux@xxxxxxxxxxxx>
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.
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