Re: [PATCH 13/17] drm/sun4i: Add DE2 CSC library

[Maxime Ripard <maxime.ripard@free-electrons.com>]

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On Tue, Nov 28, 2017 at 10:43:39PM +0100, Jernej Škrabec wrote:
> Hi!
> 
> Dne torek, 28. november 2017 ob 21:55:50 CET je Maxime Ripard napisal(a):
> > On Mon, Nov 27, 2017 at 09:57:46PM +0100, Jernej Skrabec wrote:
> > > DE2 have many CSC units - channel input CSC, channel output CSC and
> > > mixer output CSC and maybe more.
> > > 
> > > Fortunately, they have all same register layout, only base offsets
> > > differs.
> > > 
> > > Add support only for channel output CSC for now.
> > > 
> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > > ---
> > > 
> > >  drivers/gpu/drm/sun4i/Makefile    |  2 +-
> > >  drivers/gpu/drm/sun4i/sun8i_csc.c | 90
> > >  +++++++++++++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/sun4i/sun8i_csc.h | 36 ++++++++++++++++
> > >  3 files changed, 127 insertions(+), 1 deletion(-)
> > >  create mode 100644 drivers/gpu/drm/sun4i/sun8i_csc.c
> > >  create mode 100644 drivers/gpu/drm/sun4i/sun8i_csc.h
> > > 
> > > diff --git a/drivers/gpu/drm/sun4i/Makefile
> > > b/drivers/gpu/drm/sun4i/Makefile index 70df480792f9..f82cc69ede72 100644
> > > --- a/drivers/gpu/drm/sun4i/Makefile
> > > +++ b/drivers/gpu/drm/sun4i/Makefile
> > > @@ -9,7 +9,7 @@ sun4i-drm-hdmi-y		+= sun4i_hdmi_enc.o
> > > 
> > >  sun4i-drm-hdmi-y		+= sun4i_hdmi_i2c.o
> > >  sun4i-drm-hdmi-y		+= sun4i_hdmi_tmds_clk.o
> > > 
> > > -sun8i-mixer-y			+= sun8i_mixer.o sun8i_layer.o sun8i_scaler.o
> > > +sun8i-mixer-y			+= sun8i_mixer.o sun8i_layer.o sun8i_scaler.o 
> sun8i_csc.o
> > 
> > Please wrap that line.
> > 
> > >  sun4i-tcon-y			+= sun4i_crtc.o
> > >  sun4i-tcon-y			+= sun4i_dotclock.o
> > > 
> > > diff --git a/drivers/gpu/drm/sun4i/sun8i_csc.c
> > > b/drivers/gpu/drm/sun4i/sun8i_csc.c new file mode 100644
> > > index 000000000000..d48c28f8d568
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/sun4i/sun8i_csc.c
> > > @@ -0,0 +1,90 @@
> > > +/*
> > > + * Copyright (C) Jernej Skrabec <jernej.skrabec@siol.net>
> > > + *
> > > + * This program is free software; you can redistribute it and/or
> > > + * modify it under the terms of the GNU General Public License as
> > > + * published by the Free Software Foundation; either version 2 of
> > > + * the License, or (at your option) any later version.
> > > + */
> > > +
> > > +#include "sun8i_csc.h"
> > > +
> > > +static const u32 ccsc_base[2][2] = {
> > > +	{CCSC00_OFFSET, CCSC01_OFFSET},
> > > +	{CCSC10_OFFSET, CCSC11_OFFSET},
> > > +};
> > > +
> > > +/*
> > > + * Factors are in two's complement format, 10 bits for fractinal part.
> > > + * First tree values in each line are multiplication factor and last
> > > + * value is constant, which is added at the end.
> > > + */
> > > +static const u32 yuv2rgb[] = {
> > > +	0x000004A8, 0x00000000, 0x00000662, 0xFFFC845A,
> > > +	0x000004A8, 0xFFFFFE6F, 0xFFFFFCBF, 0x00021DF4,
> > > +	0x000004A8, 0x00000813, 0x00000000, 0xFFFBAC4A,
> > > +};
> > > +
> > > +static const u32 yvu2rgb[] = {
> > > +	0x000004A8, 0x00000662, 0x00000000, 0xFFFC845A,
> > > +	0x000004A8, 0xFFFFFCBF, 0xFFFFFE6F, 0x00021DF4,
> > > +	0x000004A8, 0x00000000, 0x00000813, 0xFFFBAC4A,
> > > +};
> > > +
> > > +static void sun8i_csc_set_coefficients(struct regmap *map, u32 base,
> > > +				       enum sun8i_csc_mode mode)
> > > +{
> > > +	const u32 *table;
> > > +	int i, data;
> > > +
> > > +	switch (mode) {
> > > +	case SUN8I_CSC_MODE_YUV2RGB:
> > > +		table = yuv2rgb;
> > > +		break;
> > > +	case SUN8I_CSC_MODE_YVU2RGB:
> > > +		table = yvu2rgb;
> > > +		break;
> > > +	default:
> > > +		WARN(1, "Wrong CSC mode specified.");
> > 
> > A hard warn is a bit overkill here. What about a dev_warn?
> 
> dev_warn requires device, which is not available here and seems a bit overkill 
> to have it as parameter just to print warning. What about DRM_WARN()?

Anything that doesn't make it look like the world just blew up is fine
by me :)

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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