From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Sat, 28 Mar 2015 18:13:52 +0000 (+0000)
Subject: drm/edid: add function to help find SADs
X-Git-Tag: firefly_0821_release~176^2~1252^2~2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1c73d3b10e6976919ce3caa5110e05e04326a7ec;p=firefly-linux-kernel-4.4.55.git

drm/edid: add function to help find SADs

Add a function to find the start of the SADs in the ELD.  This
complements the helper to retrieve the SAD count.

[airlied: this fixes a build problem with the alsa eld helper
which required this].

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
---

diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 799050198323..53c53c459b15 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -347,6 +347,25 @@ static inline int drm_eld_mnl(const uint8_t *eld)
 	return (eld[DRM_ELD_CEA_EDID_VER_MNL] & DRM_ELD_MNL_MASK) >> DRM_ELD_MNL_SHIFT;
 }
 
+/**
+ * drm_eld_sad - Get ELD SAD structures.
+ * @eld: pointer to an eld memory structure with sad_count set
+ */
+static inline const uint8_t *drm_eld_sad(const uint8_t *eld)
+{
+	unsigned int ver, mnl;
+
+	ver = (eld[DRM_ELD_VER] & DRM_ELD_VER_MASK) >> DRM_ELD_VER_SHIFT;
+	if (ver != 2 && ver != 31)
+		return NULL;
+
+	mnl = drm_eld_mnl(eld);
+	if (mnl > 16)
+		return NULL;
+
+	return eld + DRM_ELD_CEA_SAD(mnl, 0);
+}
+
 /**
  * drm_eld_sad_count - Get ELD SAD count.
  * @eld: pointer to an eld memory structure with sad_count set