From 780dd9c63fd7a2a60e09f01b8891bc599aa2ac5f Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Fri, 16 Oct 2009 07:42:53 -0300
Subject: [PATCH] --- yaml --- r: 173973 b: refs/heads/master c:
 fb1f9020609ead93fcec4b0dd02511a46294c147 h: refs/heads/master i:   173971:
 e3b26dcc2cad574c1abdd2e23f9cd73047e1f5eb v: v3

---
 [refs]                                  |  2 +-
 trunk/drivers/media/video/gspca/ov519.c | 53 ++++++++++++++++++++-----
 2 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/[refs] b/[refs]
index 229880918951..7ed3b013d33a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a511ba947600ae263f8c29c86020ba66a901d3e5
+refs/heads/master: fb1f9020609ead93fcec4b0dd02511a46294c147
diff --git a/trunk/drivers/media/video/gspca/ov519.c b/trunk/drivers/media/video/gspca/ov519.c
index 994a5e927d2d..91e9b23a3a01 100644
--- a/trunk/drivers/media/video/gspca/ov519.c
+++ b/trunk/drivers/media/video/gspca/ov519.c
@@ -103,6 +103,7 @@ struct sd {
 	u8 sensor_addr;
 	int sensor_width;
 	int sensor_height;
+	int sensor_reg_cache[256];
 };
 
 /* Note this is a bit of a hack, but the w9968cf driver needs the code for all
@@ -2210,38 +2211,70 @@ static int ovfx2_i2c_r(struct sd *sd, __u8 reg)
 
 static int i2c_w(struct sd *sd, __u8 reg, __u8 value)
 {
+	int ret = -1;
+
+	if (sd->sensor_reg_cache[reg] == value)
+		return 0;
+
 	switch (sd->bridge) {
 	case BRIDGE_OV511:
 	case BRIDGE_OV511PLUS:
-		return ov511_i2c_w(sd, reg, value);
+		ret = ov511_i2c_w(sd, reg, value);
+		break;
 	case BRIDGE_OV518:
 	case BRIDGE_OV518PLUS:
 	case BRIDGE_OV519:
-		return ov518_i2c_w(sd, reg, value);
+		ret = ov518_i2c_w(sd, reg, value);
+		break;
 	case BRIDGE_OVFX2:
-		return ovfx2_i2c_w(sd, reg, value);
+		ret = ovfx2_i2c_w(sd, reg, value);
+		break;
 	case BRIDGE_W9968CF:
-		return w9968cf_i2c_w(sd, reg, value);
+		ret = w9968cf_i2c_w(sd, reg, value);
+		break;
+	}
+
+	if (ret >= 0) {
+		/* Up on sensor reset empty the register cache */
+		if (reg == 0x12 && (value & 0x80))
+			memset(sd->sensor_reg_cache, -1,
+			       sizeof(sd->sensor_reg_cache));
+		else
+			sd->sensor_reg_cache[reg] = value;
 	}
-	return -1; /* Should never happen */
+
+	return ret;
 }
 
 static int i2c_r(struct sd *sd, __u8 reg)
 {
+	int ret;
+
+	if (sd->sensor_reg_cache[reg] != -1)
+		return sd->sensor_reg_cache[reg];
+
 	switch (sd->bridge) {
 	case BRIDGE_OV511:
 	case BRIDGE_OV511PLUS:
-		return ov511_i2c_r(sd, reg);
+		ret = ov511_i2c_r(sd, reg);
+		break;
 	case BRIDGE_OV518:
 	case BRIDGE_OV518PLUS:
 	case BRIDGE_OV519:
-		return ov518_i2c_r(sd, reg);
+		ret = ov518_i2c_r(sd, reg);
+		break;
 	case BRIDGE_OVFX2:
-		return ovfx2_i2c_r(sd, reg);
+		ret = ovfx2_i2c_r(sd, reg);
+		break;
 	case BRIDGE_W9968CF:
-		return w9968cf_i2c_r(sd, reg);
+		ret = w9968cf_i2c_r(sd, reg);
+		break;
 	}
-	return -1; /* Should never happen */
+
+	if (ret >= 0)
+		sd->sensor_reg_cache[reg] = ret;
+
+	return ret;
 }
 
 /* Writes bits at positions specified by mask to an I2C reg. Bits that are in