Commit 94bb4dc1 authored by Nickey Yang's avatar Nickey Yang Committed by Archit Taneja
Browse files

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: default avatarNickey Yang <nickey.yang@rock-chips.com>
Reviewed-by: default avatarDouglas Anderson <dianders@chromium.org>
Acked-by: default avatarVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: default avatarArchit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1489978651-16647-1-git-send-email-nickey.yang@rock-chips.com
parent 3a270e4d

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

+24 −14
Original line number Diff line number Diff line
@@ -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 {
@@ -247,6 +249,10 @@ static int dw_hdmi_i2c_read(struct dw_hdmi *hdmi, 
		reinit_completion(&i2c->cmp);



		hdmi_writeb(hdmi, i2c->slave_reg++, HDMI_I2CM_ADDRESS);

		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);
@@ -260,6 +266,7 @@ static int dw_hdmi_i2c_read(struct dw_hdmi *hdmi, 


		*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_adapter *adap, 
	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_adapter *adap, 
	/* 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].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);

				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);



				ret = dw_hdmi_i2c_write(hdmi, msgs[i].buf,

							msgs[i].len);

		}

		if (ret < 0)

			break;

	}

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