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Message-ID: <20171017120818.GB684@ulmo>
Date: Tue, 17 Oct 2017 14:08:18 +0200
From: Thierry Reding <thierry.reding@...il.com>
To: Lothar Waßmann <LW@...O-electronics.de>
Cc: David Airlie <airlied@...ux.ie>,
Mark Rutland <mark.rutland@....com>,
Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/9] drm/panel: simple: add a macro for defining display
modes in a simpler and less error prone way
On Wed, Oct 11, 2017 at 01:23:33PM +0200, Lothar Waßmann wrote:
> Create a macro that eases the definition of display mode parameters by
> accecpting the parameters:
> freq, hactive, hfront-porch, hsynclen, hback-porch,
> vactive, vfront-porch, vsynclen, vback-porch, vrefresh
> that can be usually directly taken from an LCD datasheet.
>
> Put the calculations that are now open coded repeating the same
> parameters multiple times into the macro expansion.
>
> Signed-off-by: Lothar Waßmann <LW@...O-electronics.de>
> ---
> drivers/gpu/drm/panel/panel-simple.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index 474fa75..dec639d 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -411,6 +411,20 @@ static const struct panel_desc ampire_am_480272h3tmqw_t01h = {
> .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
> };
>
> +#define SP_DISPLAY_MODE(freq, ha, hfp, hs, hbp, va, vfp, vs, vbp, vr, flgs) { \
> + .clock = freq, \
> + .hdisplay = ha, \
> + .hsync_start = (ha) + (hfp), \
> + .hsync_end = (ha) + (hfp) + (hs), \
> + .htotal = (ha) + (hfp) + (hs) + (hbp), \
> + .vdisplay = (va), \
> + .vsync_start = (va) + (vfp), \
> + .vsync_end = (va) + (vfp) + (vs), \
> + .vtotal = (va) + (vfp) + (vs) + (vbp), \
> + .vrefresh = vr, \
> + .flags = flgs, \
> + }
I don't think this simplifies anything. It's now completely non-obvious
which parameter is which, so you actually have to go look at the macro
definition when you add a new mode to make sure you get them right.
Thierry
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