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From be9059ee366d592ad512e717c6126e63f355b4cc Mon Sep 17 00:00:00 2001
From: Nickey Yang <nickey.yang@rock-chips.com>
Date: Mon, 20 Mar 2017 10:57:31 +0800
Subject: [PATCH 235/286] drm/bridge: dw_hdmi: support i2c extended read mode
"I2C Master Interface Extended Read Mode" implements a segment
pointer-based read operation using the Special Register configuration.
This patch fix https://patchwork.kernel.org/patch/7098101/ mentioned
"The current implementation does not support "I2C Master Interface
Extended Read Mode" to read data addressed by non-zero segment
pointer, this means that if EDID has more than 1 extension blocks,
EDID reading operation won't succeed"
With this patch, dw-hdmi can read EDID data with 1/2/4 blocks.
Signed-off-by: Nickey Yang <nickey.yang@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1489978651-16647-1-git-send-email-nickey.yang@rock-chips.com
(cherry picked from commit 94bb4dc132ed2e3a4d16649b0096c49d13670fe8)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 38 ++++++++++++++++++------------
1 file changed, 24 insertions(+), 14 deletions(-)
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -33,6 +33,7 @@
#include "dw-hdmi.h"
#include "dw-hdmi-audio.h"
+#define DDC_SEGMENT_ADDR 0x30
#define HDMI_EDID_LEN 512
#define RGB 0
@@ -112,6 +113,7 @@ struct dw_hdmi_i2c {
u8 slave_reg;
bool is_regaddr;
+ bool is_segment;
};
struct dw_hdmi_phy_data {
@@ -247,8 +249,12 @@ static int dw_hdmi_i2c_read(struct dw_hd
reinit_completion(&i2c->cmp);
hdmi_writeb(hdmi, i2c->slave_reg++, HDMI_I2CM_ADDRESS);
- hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_READ,
- HDMI_I2CM_OPERATION);
+ if (i2c->is_segment)
+ hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_READ_EXT,
+ HDMI_I2CM_OPERATION);
+ else
+ hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_READ,
+ HDMI_I2CM_OPERATION);
stat = wait_for_completion_timeout(&i2c->cmp, HZ / 10);
if (!stat)
@@ -260,6 +266,7 @@ static int dw_hdmi_i2c_read(struct dw_hd
*buf++ = hdmi_readb(hdmi, HDMI_I2CM_DATAI);
}
+ i2c->is_segment = false;
return 0;
}
@@ -309,12 +316,6 @@ static int dw_hdmi_i2c_xfer(struct i2c_a
dev_dbg(hdmi->dev, "xfer: num: %d, addr: %#x\n", num, addr);
for (i = 0; i < num; i++) {
- if (msgs[i].addr != addr) {
- dev_warn(hdmi->dev,
- "unsupported transfer, changed slave address\n");
- return -EOPNOTSUPP;
- }
-
if (msgs[i].len == 0) {
dev_dbg(hdmi->dev,
"unsupported transfer %d/%d, no data\n",
@@ -334,15 +335,24 @@ static int dw_hdmi_i2c_xfer(struct i2c_a
/* Set slave device register address on transfer */
i2c->is_regaddr = false;
+ /* Set segment pointer for I2C extended read mode operation */
+ i2c->is_segment = false;
+
for (i = 0; i < num; i++) {
dev_dbg(hdmi->dev, "xfer: num: %d/%d, len: %d, flags: %#x\n",
i + 1, num, msgs[i].len, msgs[i].flags);
-
- if (msgs[i].flags & I2C_M_RD)
- ret = dw_hdmi_i2c_read(hdmi, msgs[i].buf, msgs[i].len);
- else
- ret = dw_hdmi_i2c_write(hdmi, msgs[i].buf, msgs[i].len);
-
+ if (msgs[i].addr == DDC_SEGMENT_ADDR && msgs[i].len == 1) {
+ i2c->is_segment = true;
+ hdmi_writeb(hdmi, DDC_SEGMENT_ADDR, HDMI_I2CM_SEGADDR);
+ hdmi_writeb(hdmi, *msgs[i].buf, HDMI_I2CM_SEGPTR);
+ } else {
+ if (msgs[i].flags & I2C_M_RD)
+ ret = dw_hdmi_i2c_read(hdmi, msgs[i].buf,
+ msgs[i].len);
+ else
+ ret = dw_hdmi_i2c_write(hdmi, msgs[i].buf,
+ msgs[i].len);
+ }
if (ret < 0)
break;
}
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