[PATCH 2/4] drm/i2c: nxp-tda998x (v2)

On Thu, Jan 24, 2013 at 5:57 AM, Daniel Vetter [off-list ref] wrote:

On Tue, Jan 22, 2013 at 04:36:23PM -0600, Rob Clark wrote:

quoted

Driver for the NXP TDA998X i2c hdmi encoder slave.

v1: original
v2: fix npix/nline programming

Signed-off-by: Rob Clark <redacted>

Just one bikeshed, otherwise

Reviewed-by: Daniel Vetter <redacted>

[cut]

quoted

+static void
+reg_set(struct drm_encoder *encoder, uint16_t reg, uint8_t val)
+{
+     reg_write(encoder, reg, reg_read(encoder, reg) | val);
+}
+
+static void
+reg_clear(struct drm_encoder *encoder, uint16_t reg, uint8_t val)
+{
+     reg_write(encoder, reg, reg_read(encoder, reg) & ~val);
+}

What about drivers/base/regmap? I haven't looked to closely yet and never
used it in code, but there's a presentation [1] and it sounds like it
provides some nice (and more important standardized) helper stuff for
debug, tracing, ...

Since encoder slave drivers tend to be utterly boring register bashing and
we expect tons of time, I think high levels of standardization would be
really useful. Care to look into this a bit?

I did look at regmap.. what convinced me against using it was that if
you don't use cached mode, it ends up writing the page selector
register for every read/write.  And I don't have enough actual
documentation about this nxp part to know the reset values of all the
registers in order to use caching.

BR,
-R

Cheers, Daniel

1: http://free-electrons.com/blog/fosdem2012-videos/
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch