On Thu, Dec 18, 2014 at 02:49:28PM +0200, Laurent Pinchart wrote: > Hi Wolfram, > > On Thursday 18 December 2014 09:21:51 Wolfram Sang wrote: > > On Thu, Dec 18, 2014 at 04:15:23AM +0200, Laurent Pinchart wrote: > > > The I2C subsystem can match devices without explicit OF support based on > > > the part of their compatible property after the comma. However, this > > > mechanism uses the first compatible value only. For adxl34x OF device > > > nodes the compatible property should list the more specific > > > "adi,adxl345" or "adi,adxl346" value first and the "adi,adxl34x" > > > fallback value second. This prevents the device node from being matched > > > with the adxl34x driver. > > > > > > Fix this by adding an OF match table with an "adi,adxl34x" compatible > > > entry. > > > > > > Signed-off-by: Laurent Pinchart > > > <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> > > > --- > > > > > > drivers/input/misc/adxl34x-i2c.c | 11 +++++++++++ > > > 1 file changed, 11 insertions(+) > > > > > > Another option would have been to add "adxl325" and "adxl326" entries to > > > the adxl34x_id I2C match table, but it would have had the drawback of > > > requiring a driver update for every new device. > > > > AFAIK this is even required for compatible entries, to be as specific as > > possible. I think this makes sense. With platform_ids, we already had > > the problem that pca954x was too generic and was used for both GPIO > > extenders and I2C muxers (IIRC). > > There are three compatible strings defined for the ADXL345 and ADXL346 in > Documentation/devicetree/bindings/i2c/trivial-devices.txt: "adi,adxl345", > "adi,adxl346", "adi,adxl34x". Given that the last one is a fallback for the > first two I don't see a need to add the specific compatible strings to the > driver for now. If a new totally incompatible chip named ADXL347 comes out we > will need a new driver which won't be allowed to use the "adi,adxl34x" > compatible string. Been there, got bitten. We only found out too late, because one driver was in i2c and the other in GPIO (or LED even?), both using "953x" :( > An option would be to remove "adi,adxl34x" from > Documentation/devicetree/bindings/i2c/trivial-devices.txt, in which case the > driver should match explicitly on "adi,adxl345" and "adi,adxl346". That might > clash with the DT ABI stability requirements though. I do prefer this: 1) add specific compatible values to the driver. We do those updates for new devices all the time 2) also add "34x" as a compatible but mark it as deprecateed 3) delete "34x" from trivial devices Everyone OK with that? Thanks, Wolfram
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