Re: [PATCH] media: i2c: adv7343: fix the DT binding properties

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Prabhakar,

On Monday 30 September 2013 18:57:01 Prabhakar Lad wrote:
> On Mon, Sep 23, 2013 at 8:18 AM, Prabhakar Lad wrote:
> > On Fri, Sep 20, 2013 at 3:22 PM, Sylwester Nawrocki wrote:
> >> On 09/20/2013 10:11 AM, Prabhakar Lad wrote:
> >>> OK I will, just send out a fix up patch which fixes the mismatch between
> >>> names for the rc-cycle, and later send out a patch which removes the
> >>> platform data usage for next release with proper DT bindings.
> >> 
> >> I think the binding need to be fully corrected now, I just meant to not
> >> touch the board file, i.e. leave non-dt support unchanged.
> > 
> > Ok
> > 
> >>> I'm OK with making regulator properties as optional, But still it would
> >>> change the meaning of what DT is, we know that the VDD/VDD_IO .. etc
> >>> pins are required properties (but still making them as optional) :-(
> >>> 
> >>> I think there might several devices where this situation may arise so
> >>> just thinking of a alternative solution.
> >>> 
> >>> say we have property 'software-regulator' which takes true/false(0/1)
> >>> If set to true we make the regulators as required property or else we
> >>> assume it is handled and ignore it ?
> >> 
> >> I don't think this is a good idea. You would have to add a similar
> >> platform data flag for non-dt, it doesn't sound right. I can see two
> >> options here:
> >> 
> >> 1. Make the regulator properties mandatory and, e.g. define a fixed
> >>    voltage GPIO regulator in DT with an empty 'gpio' property. Then
> >>    pass a phandle to that regulator in the adv7343 *-supply properties.
> >>    For non-dt similarly a fixed voltage regulator(s) and voltage
> >>    supplies  would need to be defined in the board files.
> >> 
> >> 2. Make the properties optional and use (devm_)regulator_get_optional()
> >>    calls in the driver (a recently added function). I must admit I don't
> >>    fully understand description of this function, it currently looks
> >>    pretty much same as (devm_)regulator_get(). Thus the driver would
> >>    need to be handling regulator supplies only when non ERR_PTR() is
> >>    returned from regulator_get_optional() and otherwise assume a non
> >>    critical error. There is already quite a few example occurrences of
> >>    regulator_get_optional() usage.
> 
> The same question arises in case of the clock, The adv7343 encoder has two
> input clocks CLKIN_A and CLKIN_B. I case of da850 EVM the clock source to
> adv7343 encoder is fixed source which is enabled by default so none of the
> bridge nor the adv7343 driver cares of the clock to enable/disable. So in
> this case should I be registering  (v4l2_clk_register() /
> v4l2_clk_unregister()) a dummy clock in the bridge driver or in the board
> file ?

The fixed clock (which is a real clock, not a dummy clock) should be 
registered in board file, preferably using the common clock framework if 
that's available on your platform.

-- 
Regards,

Laurent Pinchart