drm/modes: Introduce the tv_mode property as a command-line option

Our new tv mode option allows to specify the TV mode from a property.
However, it can still be useful, for example to avoid any boot time
artifact, to set that property directly from the kernel command line.

Let's add some code to allow it, and some unit tests to exercise that code.

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Acked-in-principle-or-something-like-that-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v10-8-256dad125326@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

1 files changed, 34 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 9426c87df623..f9fe065f189b 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -2135,6 +2135,30 @@ static int drm_mode_parse_panel_orientation(const char *delim,
 	return 0;
 }
 
+static int drm_mode_parse_tv_mode(const char *delim,
+				  struct drm_cmdline_mode *mode)
+{
+	const char *value;
+	int ret;
+
+	if (*delim != '=')
+		return -EINVAL;
+
+	value = delim + 1;
+	delim = strchr(value, ',');
+	if (!delim)
+		delim = value + strlen(value);
+
+	ret = drm_get_tv_mode_from_name(value, delim - value);
+	if (ret < 0)
+		return ret;
+
+	mode->tv_mode_specified = true;
+	mode->tv_mode = ret;
+
+	return 0;
+}
+
 static int drm_mode_parse_cmdline_options(const char *str,
 					  bool freestanding,
 					  const struct drm_connector *connector,
@@ -2204,6 +2228,9 @@ static int drm_mode_parse_cmdline_options(const char *str,
 		} else if (!strncmp(option, "panel_orientation", delim - option)) {
 			if (drm_mode_parse_panel_orientation(delim, mode))
 				return -EINVAL;
+		} else if (!strncmp(option, "tv_mode", delim - option)) {
+			if (drm_mode_parse_tv_mode(delim, mode))
+				return -EINVAL;
 		} else {
 			return -EINVAL;
 		}
@@ -2232,20 +2259,22 @@ struct drm_named_mode {
 	unsigned int xres;
 	unsigned int yres;
 	unsigned int flags;
+	unsigned int tv_mode;
 };
 
-#define NAMED_MODE(_name, _pclk, _x, _y, _flags)	\
+#define NAMED_MODE(_name, _pclk, _x, _y, _flags, _mode)	\
 	{						\
 		.name = _name,				\
 		.pixel_clock_khz = _pclk,		\
 		.xres = _x,				\
 		.yres = _y,				\
 		.flags = _flags,			\
+		.tv_mode = _mode,			\
 	}
 
 static const struct drm_named_mode drm_named_modes[] = {
-	NAMED_MODE("NTSC", 13500, 720, 480, DRM_MODE_FLAG_INTERLACE),
-	NAMED_MODE("PAL", 13500, 720, 576, DRM_MODE_FLAG_INTERLACE),
+	NAMED_MODE("NTSC", 13500, 720, 480, DRM_MODE_FLAG_INTERLACE, DRM_MODE_TV_MODE_NTSC),
+	NAMED_MODE("PAL", 13500, 720, 576, DRM_MODE_FLAG_INTERLACE, DRM_MODE_TV_MODE_PAL),
 };
 
 static int drm_mode_parse_cmdline_named_mode(const char *name,
@@ -2290,6 +2319,8 @@ static int drm_mode_parse_cmdline_named_mode(const char *name,
 		cmdline_mode->xres = mode->xres;
 		cmdline_mode->yres = mode->yres;
 		cmdline_mode->interlace = !!(mode->flags & DRM_MODE_FLAG_INTERLACE);
+		cmdline_mode->tv_mode = mode->tv_mode;
+		cmdline_mode->tv_mode_specified = true;
 		cmdline_mode->specified = true;
 
 		return 1;