[PATCH 1/5] drm: Get supported channel from SAD

[Mitul Golani]

Add DRM helper to get supported channel values from SAD.
Supported channel value can be obtained by extracting
the first byte of SAD.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani at intel.com>
---
 drivers/gpu/drm/drm_edid.c | 12 ++++++++++++
 include/drm/drm_edid.h     |  4 ++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 0454da505687..e99ed37fafc3 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -7309,3 +7309,15 @@ static void _drm_update_tile_info(struct drm_connector *connector,
 		connector->tile_group = NULL;
 	}
 }
+
+/*
+ * drm_sad_to_channels - extract channels of an SAD
+ * @sad: pointer to an sad
+ *
+ * extract number of supported channels from byte 0 of SAD
+ */
+unsigned int drm_sad_to_channels(const u8 *sad)
+{
+	return 1 + (sad[0] & DRM_ELD_SAD_CHANNELS_MASK);
+}
+EXPORT_SYMBOL(drm_sad_to_channels);
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 571885d32907..35f22da35fcc 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -307,6 +307,8 @@ struct detailed_timing {
 # define DRM_ELD_SUPPORTS_AI		(1 << 1)
 # define DRM_ELD_SUPPORTS_HDCP		(1 << 0)
 
+#define	DRM_ELD_SAD_CHANNELS_MASK	0x7
+
 #define DRM_ELD_AUD_SYNCH_DELAY		6	/* in units of 2 ms */
 # define DRM_ELD_AUD_SYNCH_DELAY_MAX	0xfa	/* 500 ms */
 
@@ -393,6 +395,8 @@ int drm_edid_to_speaker_allocation(const struct edid *edid, u8 **sadb);
 int drm_av_sync_delay(struct drm_connector *connector,
 		      const struct drm_display_mode *mode);
 
+unsigned int drm_sad_to_channels(const u8 *sad);
+
 #ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
 int __drm_set_edid_firmware_path(const char *path);
 int __drm_get_edid_firmware_path(char *buf, size_t bufsize);
-- 
2.25.1