drm/modes: parse_cmdline: Add support for specifying panel_orientation (v2)

Sometimes we want to override a connector's panel_orientation from the
kernel commandline. Either for testing and for special cases, e.g. a kiosk
like setup which uses a TV mounted in portrait mode.

Users can already specify a "rotate" option through a video= kernel cmdline
option. But that only supports 0/180 degrees (see drm_client_modeset TODO)
and only works for in kernel modeset clients, not for userspace kms users.

The "panel-orientation" connector property OTOH does support 90/270 degrees
as it leaves dealing with the rotation up to userspace and this does work
for userspace kms clients (at least those which support this property).

Changes in v2:
-Add missing ':' after @panel_orientation (reported by kbuild test robot)

BugLink: https://gitlab.freedesktop.org/plymouth/plymouth/merge_requests/83
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191118155134.30468-9-hdegoede@redhat.com

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 2e82603f5d0a..119fed7ab815 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1591,6 +1591,33 @@ static int drm_mode_parse_cmdline_int(const char *delim, unsigned int *int_ret)
 	return 0;
 }
 
+static int drm_mode_parse_panel_orientation(const char *delim,
+					    struct drm_cmdline_mode *mode)
+{
+	const char *value;
+
+	if (*delim != '=')
+		return -EINVAL;
+
+	value = delim + 1;
+	delim = strchr(value, ',');
+	if (!delim)
+		delim = value + strlen(value);
+
+	if (!strncmp(value, "normal", delim - value))
+		mode->panel_orientation = DRM_MODE_PANEL_ORIENTATION_NORMAL;
+	else if (!strncmp(value, "upside_down", delim - value))
+		mode->panel_orientation = DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP;
+	else if (!strncmp(value, "left_side_up", delim - value))
+		mode->panel_orientation = DRM_MODE_PANEL_ORIENTATION_LEFT_UP;
+	else if (!strncmp(value, "right_side_up", delim - value))
+		mode->panel_orientation = DRM_MODE_PANEL_ORIENTATION_RIGHT_UP;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
 static int drm_mode_parse_cmdline_options(const char *str,
 					  bool freestanding,
 					  const struct drm_connector *connector,
@@ -1657,6 +1684,9 @@ static int drm_mode_parse_cmdline_options(const char *str,
 				return -EINVAL;
 
 			mode->tv_margins.bottom = margin;
+		} else if (!strncmp(option, "panel_orientation", delim - option)) {
+			if (drm_mode_parse_panel_orientation(delim, mode))
+				return -EINVAL;
 		} else {
 			return -EINVAL;
 		}
@@ -1715,6 +1745,8 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 	char *bpp_end_ptr = NULL, *refresh_end_ptr = NULL;
 	int i, len, ret;
 
+	mode->panel_orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
+
 #ifdef CONFIG_FB
 	if (!mode_option)
 		mode_option = fb_mode_option;