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From 2e2b673a2a47e8358ef92ec4019be87552949304 Mon Sep 17 00:00:00 2001
From: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Date: Wed, 9 Aug 2017 11:52:22 +0300
Subject: [PATCH] drm: adv7511: use smbus to retrieve edid
Get EDID using smbus protocol instead block i2c transfer
This fixes often checksum errors while retriving EDID at 400kHz bus speed
Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
---
drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index d3ece87..b2e1b58 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -500,18 +500,19 @@ static int adv7511_get_edid_block(void *data, u8 *buf, unsigned int block,
* support 64 byte transfers than 256 byte transfers
*/
+#define CHUNK_SIZE 1
xfer[0].addr = adv7511->i2c_edid->addr;
xfer[0].flags = 0;
xfer[0].len = 1;
xfer[0].buf = &offset;
xfer[1].addr = adv7511->i2c_edid->addr;
xfer[1].flags = I2C_M_RD;
- xfer[1].len = 64;
+ xfer[1].len = CHUNK_SIZE;
xfer[1].buf = adv7511->edid_buf;
offset = 0;
- for (i = 0; i < 4; ++i) {
+ for (i = 0; i < 256/CHUNK_SIZE; ++i) {
ret = i2c_transfer(adv7511->i2c_edid->adapter, xfer,
ARRAY_SIZE(xfer));
if (ret < 0)
@@ -519,8 +520,8 @@ static int adv7511_get_edid_block(void *data, u8 *buf, unsigned int block,
else if (ret != 2)
return -EIO;
- xfer[1].buf += 64;
- offset += 64;
+ xfer[1].buf += CHUNK_SIZE;
+ offset += CHUNK_SIZE;
}
adv7511->current_edid_segment = block / 2;
--
1.9.1
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