0011-drm-i2c-nxp-tda998x-fix-EDID-reading-on-TDA19988-dev.patch

From f35574ad3fc70d28d8b681ae6a6c09d62e3e3ab3 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Thu, 16 May 2013 19:25:58 +0000
Subject: [PATCH 11/27] drm/i2c: nxp-tda998x: fix EDID reading on TDA19988
 devices

TDA19988 devices need their RAM enabled in order to read EDID
information.  Add support for this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 drivers/gpu/drm/i2c/tda998x_drv.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 412ba4f..9ac4ed9 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -253,6 +253,8 @@ struct tda998x_priv {
 
 /* Page 12h: HDCP and OTP */
 #define REG_TX3                   REG(0x12, 0x9a)     /* read/write */
+#define REG_TX4                   REG(0x12, 0x9b)     /* read/write */
+# define TX4_PD_RAM               (1 << 1)
 #define REG_TX33                  REG(0x12, 0xb8)     /* read/write */
 # define TX33_HDMI                (1 << 1)
 
@@ -865,6 +867,7 @@ read_edid_block(struct drm_encoder *encoder, uint8_t *buf, int blk)
 static uint8_t *
 do_get_edid(struct drm_encoder *encoder)
 {
+	struct tda998x_priv *priv = to_tda998x_priv(encoder);
 	int j = 0, valid_extensions = 0;
 	uint8_t *block, *new;
 	bool print_bad_edid = drm_debug & DRM_UT_KMS;
@@ -872,6 +875,9 @@ do_get_edid(struct drm_encoder *encoder)
 	if ((block = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
 		return NULL;
 
+	if (priv->rev == TDA19988)
+		reg_clear(encoder, REG_TX4, TX4_PD_RAM);
+
 	/* base block fetch */
 	if (read_edid_block(encoder, block, 0))
 		goto fail;
@@ -881,7 +887,7 @@ do_get_edid(struct drm_encoder *encoder)
 
 	/* if there's no extensions, we're done */
 	if (block[0x7e] == 0)
-		return block;
+		goto done;
 
 	new = krealloc(block, (block[0x7e] + 1) * EDID_LENGTH, GFP_KERNEL);
 	if (!new)
@@ -908,9 +914,15 @@ do_get_edid(struct drm_encoder *encoder)
 		block = new;
 	}
 
+done:
+	if (priv->rev == TDA19988)
+		reg_set(encoder, REG_TX4, TX4_PD_RAM);
+
 	return block;
 
 fail:
+	if (priv->rev == TDA19988)
+		reg_set(encoder, REG_TX4, TX4_PD_RAM);
 	dev_warn(encoder->dev->dev, "failed to read EDID\n");
 	kfree(block);
 	return NULL;
-- 
1.8.2.1