drm/bridge: analogix_dp: Remove duplicated code

Remove code for reading the EDID and DPCD fields and use the helpers
instead.

Besides the obvious code reduction, other helpers are being added to the
core that could be used in this driver and will be good to be able to
use them instead of duplicating them.

Signed-off-by: Tomeu Vizoso <[e-mail]>
Tested-by: Javier Martinez Canillas <[e-mail]>
Tested-by: Sean Paul <[e-mail]>
Reviewed-by: Sean Paul <[e-mail]>
Reviewed-by: Yakir Yang <[e-mail]>
Signed-off-by: Sean Paul <[e-mail]>
Cc: Javier Martinez Canillas <[e-mail]>
Cc: Mika Kahola <[e-mail]>
Cc: Yakir Yang <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: Archit Taneja <[e-mail]>

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c

···
 #include <drm/bridge/analogix_dp.h>
 
 #include "analogix_dp_core.h"
+#include "analogix_dp_reg.h"
 
 #define to_dp(nm)	container_of(nm, struct analogix_dp_device, nm)
 
···
 {
 	unsigned char psr_version;
 
-	analogix_dp_read_byte_from_dpcd(dp, DP_PSR_SUPPORT, &psr_version);
+	drm_dp_dpcd_readb(&dp->aux, DP_PSR_SUPPORT, &psr_version);
 	dev_dbg(dp->dev, "Panel PSR version : %x\n", psr_version);
 
 	return (psr_version & DP_PSR_IS_SUPPORTED) ? true : false;
···
 	unsigned char psr_en;
 
 	/* Disable psr function */
-	analogix_dp_read_byte_from_dpcd(dp, DP_PSR_EN_CFG, &psr_en);
+	drm_dp_dpcd_readb(&dp->aux, DP_PSR_EN_CFG, &psr_en);
 	psr_en &= ~DP_PSR_ENABLE;
-	analogix_dp_write_byte_to_dpcd(dp, DP_PSR_EN_CFG, psr_en);
+	drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
 
 	/* Main-Link transmitter remains active during PSR active states */
 	psr_en = DP_PSR_MAIN_LINK_ACTIVE | DP_PSR_CRC_VERIFICATION;
-	analogix_dp_write_byte_to_dpcd(dp, DP_PSR_EN_CFG, psr_en);
+	drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
 
 	/* Enable psr function */
 	psr_en = DP_PSR_ENABLE | DP_PSR_MAIN_LINK_ACTIVE |
 		 DP_PSR_CRC_VERIFICATION;
-	analogix_dp_write_byte_to_dpcd(dp, DP_PSR_EN_CFG, psr_en);
+	drm_dp_dpcd_writeb(&dp->aux, DP_PSR_EN_CFG, psr_en);
 
 	analogix_dp_enable_psr_crc(dp);
-}
-
-static unsigned char analogix_dp_calc_edid_check_sum(unsigned char *edid_data)
-{
-	int i;
-	unsigned char sum = 0;
-
-	for (i = 0; i < EDID_BLOCK_LENGTH; i++)
-		sum = sum + edid_data[i];
-
-	return sum;
-}
-
-static int analogix_dp_read_edid(struct analogix_dp_device *dp)
-{
-	unsigned char *edid = dp->edid;
-	unsigned int extend_block = 0;
-	unsigned char sum;
-	unsigned char test_vector;
-	int retval;
-
-	/*
-	 * EDID device address is 0x50.
-	 * However, if necessary, you must have set upper address
-	 * into E-EDID in I2C device, 0x30.
-	 */
-
-	/* Read Extension Flag, Number of 128-byte EDID extension blocks */
-	retval = analogix_dp_read_byte_from_i2c(dp, I2C_EDID_DEVICE_ADDR,
-						EDID_EXTENSION_FLAG,
-						&extend_block);
-	if (retval)
-		return retval;
-
-	if (extend_block > 0) {
-		dev_dbg(dp->dev, "EDID data includes a single extension!\n");
-
-		/* Read EDID data */
-		retval = analogix_dp_read_bytes_from_i2c(dp,
-						I2C_EDID_DEVICE_ADDR,
-						EDID_HEADER_PATTERN,
-						EDID_BLOCK_LENGTH,
-						&edid[EDID_HEADER_PATTERN]);
-		if (retval != 0) {
-			dev_err(dp->dev, "EDID Read failed!\n");
-			return -EIO;
-		}
-		sum = analogix_dp_calc_edid_check_sum(edid);
-		if (sum != 0) {
-			dev_err(dp->dev, "EDID bad checksum!\n");
-			return -EIO;
-		}
-
-		/* Read additional EDID data */
-		retval = analogix_dp_read_bytes_from_i2c(dp,
-				I2C_EDID_DEVICE_ADDR,
-				EDID_BLOCK_LENGTH,
-				EDID_BLOCK_LENGTH,
-				&edid[EDID_BLOCK_LENGTH]);
-		if (retval != 0) {
-			dev_err(dp->dev, "EDID Read failed!\n");
-			return -EIO;
-		}
-		sum = analogix_dp_calc_edid_check_sum(&edid[EDID_BLOCK_LENGTH]);
-		if (sum != 0) {
-			dev_err(dp->dev, "EDID bad checksum!\n");
-			return -EIO;
-		}
-
-		analogix_dp_read_byte_from_dpcd(dp, DP_TEST_REQUEST,
-						&test_vector);
-		if (test_vector & DP_TEST_LINK_EDID_READ) {
-			analogix_dp_write_byte_to_dpcd(dp,
-				DP_TEST_EDID_CHECKSUM,
-				edid[EDID_BLOCK_LENGTH + EDID_CHECKSUM]);
-			analogix_dp_write_byte_to_dpcd(dp,
-				DP_TEST_RESPONSE,
-				DP_TEST_EDID_CHECKSUM_WRITE);
-		}
-	} else {
-		dev_info(dp->dev, "EDID data does not include any extensions.\n");
-
-		/* Read EDID data */
-		retval = analogix_dp_read_bytes_from_i2c(dp,
-				I2C_EDID_DEVICE_ADDR, EDID_HEADER_PATTERN,
-				EDID_BLOCK_LENGTH, &edid[EDID_HEADER_PATTERN]);
-		if (retval != 0) {
-			dev_err(dp->dev, "EDID Read failed!\n");
-			return -EIO;
-		}
-		sum = analogix_dp_calc_edid_check_sum(edid);
-		if (sum != 0) {
-			dev_err(dp->dev, "EDID bad checksum!\n");
-			return -EIO;
-		}
-
-		analogix_dp_read_byte_from_dpcd(dp, DP_TEST_REQUEST,
-						&test_vector);
-		if (test_vector & DP_TEST_LINK_EDID_READ) {
-			analogix_dp_write_byte_to_dpcd(dp,
-				DP_TEST_EDID_CHECKSUM, edid[EDID_CHECKSUM]);
-			analogix_dp_write_byte_to_dpcd(dp,
-				DP_TEST_RESPONSE, DP_TEST_EDID_CHECKSUM_WRITE);
-		}
-	}
-
-	dev_dbg(dp->dev, "EDID Read success!\n");
-	return 0;
-}
-
-static int analogix_dp_handle_edid(struct analogix_dp_device *dp)
-{
-	u8 buf[12];
-	int i;
-	int retval;
-
-	/* Read DPCD DP_DPCD_REV~RECEIVE_PORT1_CAP_1 */
-	retval = analogix_dp_read_bytes_from_dpcd(dp, DP_DPCD_REV, 12, buf);
-	if (retval)
-		return retval;
-
-	/* Read EDID */
-	for (i = 0; i < 3; i++) {
-		retval = analogix_dp_read_edid(dp);
-		if (!retval)
-			break;
-	}
-
-	return retval;
 }
 
 static void
···
 {
 	u8 data;
 
-	analogix_dp_read_byte_from_dpcd(dp, DP_LANE_COUNT_SET, &data);
+	drm_dp_dpcd_readb(&dp->aux, DP_LANE_COUNT_SET, &data);
 
 	if (enable)
-		analogix_dp_write_byte_to_dpcd(dp, DP_LANE_COUNT_SET,
-					       DP_LANE_COUNT_ENHANCED_FRAME_EN |
-					       DPCD_LANE_COUNT_SET(data));
+		drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET,
+				   DP_LANE_COUNT_ENHANCED_FRAME_EN |
+					DPCD_LANE_COUNT_SET(data));
 	else
-		analogix_dp_write_byte_to_dpcd(dp, DP_LANE_COUNT_SET,
-					       DPCD_LANE_COUNT_SET(data));
+		drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET,
+				   DPCD_LANE_COUNT_SET(data));
 }
 
 static int analogix_dp_is_enhanced_mode_available(struct analogix_dp_device *dp)
···
 	u8 data;
 	int retval;
 
-	analogix_dp_read_byte_from_dpcd(dp, DP_MAX_LANE_COUNT, &data);
+	drm_dp_dpcd_readb(&dp->aux, DP_MAX_LANE_COUNT, &data);
 	retval = DPCD_ENHANCED_FRAME_CAP(data);
 
 	return retval;
···
 {
 	analogix_dp_set_training_pattern(dp, DP_NONE);
 
-	analogix_dp_write_byte_to_dpcd(dp, DP_TRAINING_PATTERN_SET,
-				       DP_TRAINING_PATTERN_DISABLE);
+	drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+			   DP_TRAINING_PATTERN_DISABLE);
 }
 
 static void
···
 	/* Setup RX configuration */
 	buf[0] = dp->link_train.link_rate;
 	buf[1] = dp->link_train.lane_count;
-	retval = analogix_dp_write_bytes_to_dpcd(dp, DP_LINK_BW_SET, 2, buf);
-	if (retval)
+	retval = drm_dp_dpcd_write(&dp->aux, DP_LINK_BW_SET, buf, 2);
+	if (retval < 0)
 		return retval;
 
 	/* Set TX pre-emphasis to minimum */
···
 	analogix_dp_set_training_pattern(dp, TRAINING_PTN1);
 
 	/* Set RX training pattern */
-	retval = analogix_dp_write_byte_to_dpcd(dp,
-			DP_TRAINING_PATTERN_SET,
-			DP_LINK_SCRAMBLING_DISABLE | DP_TRAINING_PATTERN_1);
-	if (retval)
+	retval = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+				    DP_LINK_SCRAMBLING_DISABLE |
+					DP_TRAINING_PATTERN_1);
+	if (retval < 0)
 		return retval;
 
 	for (lane = 0; lane < lane_count; lane++)
 		buf[lane] = DP_TRAIN_PRE_EMPH_LEVEL_0 |
 			    DP_TRAIN_VOLTAGE_SWING_LEVEL_0;
 
-	retval = analogix_dp_write_bytes_to_dpcd(dp, DP_TRAINING_LANE0_SET,
-						 lane_count, buf);
+	retval = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET, buf,
+				   lane_count);
+	if (retval < 0)
+		return retval;
 
-	return retval;
+	return 0;
 }
 
 static unsigned char analogix_dp_get_lane_status(u8 link_status[2], int lane)
···
 
 	lane_count = dp->link_train.lane_count;
 
-	retval =  analogix_dp_read_bytes_from_dpcd(dp,
-			DP_LANE0_1_STATUS, 2, link_status);
-	if (retval)
+	retval = drm_dp_dpcd_read(&dp->aux, DP_LANE0_1_STATUS, link_status, 2);
+	if (retval < 0)
 		return retval;
 
-	retval =  analogix_dp_read_bytes_from_dpcd(dp,
-			DP_ADJUST_REQUEST_LANE0_1, 2, adjust_request);
-	if (retval)
+	retval = drm_dp_dpcd_read(&dp->aux, DP_ADJUST_REQUEST_LANE0_1,
+				  adjust_request, 2);
+	if (retval < 0)
 		return retval;
 
 	if (analogix_dp_clock_recovery_ok(link_status, lane_count) == 0) {
 		/* set training pattern 2 for EQ */
 		analogix_dp_set_training_pattern(dp, TRAINING_PTN2);
 
-		retval = analogix_dp_write_byte_to_dpcd(dp,
-				DP_TRAINING_PATTERN_SET,
-				DP_LINK_SCRAMBLING_DISABLE |
-				DP_TRAINING_PATTERN_2);
-		if (retval)
+		retval = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+					    DP_LINK_SCRAMBLING_DISABLE |
+						DP_TRAINING_PATTERN_2);
+		if (retval < 0)
 			return retval;
 
 		dev_info(dp->dev, "Link Training Clock Recovery success\n");
···
 		analogix_dp_set_lane_link_training(dp,
 			dp->link_train.training_lane[lane], lane);
 
-	retval = analogix_dp_write_bytes_to_dpcd(dp,
-			DP_TRAINING_LANE0_SET, lane_count,
-			dp->link_train.training_lane);
-	if (retval)
+	retval = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET,
+				   dp->link_train.training_lane, lane_count);
+	if (retval < 0)
 		return retval;
 
-	return retval;
+	return 0;
 }
 
 static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
···
 
 	lane_count = dp->link_train.lane_count;
 
-	retval = analogix_dp_read_bytes_from_dpcd(dp,
-			DP_LANE0_1_STATUS, 2, link_status);
-	if (retval)
+	retval = drm_dp_dpcd_read(&dp->aux, DP_LANE0_1_STATUS, link_status, 2);
+	if (retval < 0)
 		return retval;
 
 	if (analogix_dp_clock_recovery_ok(link_status, lane_count)) {
···
 		return -EIO;
 	}
 
-	retval = analogix_dp_read_bytes_from_dpcd(dp,
-			DP_ADJUST_REQUEST_LANE0_1, 2, adjust_request);
-	if (retval)
+	retval = drm_dp_dpcd_read(&dp->aux, DP_ADJUST_REQUEST_LANE0_1,
+				  adjust_request, 2);
+	if (retval < 0)
 		return retval;
 
-	retval = analogix_dp_read_byte_from_dpcd(dp,
-			DP_LANE_ALIGN_STATUS_UPDATED, &link_align);
-	if (retval)
+	retval = drm_dp_dpcd_readb(&dp->aux, DP_LANE_ALIGN_STATUS_UPDATED,
+				   &link_align);
+	if (retval < 0)
 		return retval;
 
 	analogix_dp_get_adjust_training_lane(dp, adjust_request);
···
 		analogix_dp_set_lane_link_training(dp,
 			dp->link_train.training_lane[lane], lane);
 
-	retval = analogix_dp_write_bytes_to_dpcd(dp, DP_TRAINING_LANE0_SET,
-			lane_count, dp->link_train.training_lane);
+	retval = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET,
+				   dp->link_train.training_lane, lane_count);
+	if (retval < 0)
+		return retval;
 
-	return retval;
+	return 0;
 }
 
 static void analogix_dp_get_max_rx_bandwidth(struct analogix_dp_device *dp,
···
 	 * For DP rev.1.2, Maximum link rate of Main Link lanes
 	 * 0x06 = 1.62 Gbps, 0x0a = 2.7 Gbps, 0x14 = 5.4Gbps
 	 */
-	analogix_dp_read_byte_from_dpcd(dp, DP_MAX_LINK_RATE, &data);
+	drm_dp_dpcd_readb(&dp->aux, DP_MAX_LINK_RATE, &data);
 	*bandwidth = data;
 }
 
···
 	 * For DP rev.1.1, Maximum number of Main Link lanes
 	 * 0x01 = 1 lane, 0x02 = 2 lanes, 0x04 = 4 lanes
 	 */
-	analogix_dp_read_byte_from_dpcd(dp, DP_MAX_LANE_COUNT, &data);
+	drm_dp_dpcd_readb(&dp->aux, DP_MAX_LANE_COUNT, &data);
 	*lane_count = DPCD_MAX_LANE_COUNT(data);
 }
 
···
 	if (enable) {
 		analogix_dp_enable_scrambling(dp);
 
-		analogix_dp_read_byte_from_dpcd(dp, DP_TRAINING_PATTERN_SET,
-						&data);
-		analogix_dp_write_byte_to_dpcd(dp,
-			DP_TRAINING_PATTERN_SET,
-			(u8)(data & ~DP_LINK_SCRAMBLING_DISABLE));
+		drm_dp_dpcd_readb(&dp->aux, DP_TRAINING_PATTERN_SET, &data);
+		drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+				   (u8)(data & ~DP_LINK_SCRAMBLING_DISABLE));
 	} else {
 		analogix_dp_disable_scrambling(dp);
 
-		analogix_dp_read_byte_from_dpcd(dp, DP_TRAINING_PATTERN_SET,
-						&data);
-		analogix_dp_write_byte_to_dpcd(dp,
-			DP_TRAINING_PATTERN_SET,
-			(u8)(data | DP_LINK_SCRAMBLING_DISABLE));
+		drm_dp_dpcd_readb(&dp->aux, DP_TRAINING_PATTERN_SET, &data);
+		drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
+				   (u8)(data | DP_LINK_SCRAMBLING_DISABLE));
 	}
 }
 
···
 int analogix_dp_get_modes(struct drm_connector *connector)
 {
 	struct analogix_dp_device *dp = to_dp(connector);
-	struct edid *edid = (struct edid *)dp->edid;
+	struct edid *edid;
 	int ret, num_modes = 0;
 
 	ret = analogix_dp_prepare_panel(dp, true, false);
···
 		return 0;
 	}
 
-	if (analogix_dp_handle_edid(dp) == 0) {
+	edid = drm_get_edid(connector, &dp->aux.ddc);
+	if (edid) {
 		drm_mode_connector_update_edid_property(&dp->connector, edid);
 		num_modes += drm_add_edid_modes(&dp->connector, edid);
+		kfree(edid);
 	}
 
 	if (dp->plat_data->panel)
···
 	return 0;
 }
 
+static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux,
+				       struct drm_dp_aux_msg *msg)
+{
+	struct analogix_dp_device *dp = to_dp(aux);
+
+	return analogix_dp_transfer(dp, msg);
+}
+
 int analogix_dp_bind(struct device *dev, struct drm_device *drm_dev,
 		     struct analogix_dp_plat_data *plat_data)
 {
···
 
 	dp->drm_dev = drm_dev;
 	dp->encoder = dp->plat_data->encoder;
+
+	dp->aux.name = "DP-AUX";
+	dp->aux.transfer = analogix_dpaux_transfer;
+	dp->aux.dev = &pdev->dev;
+
+	ret = drm_dp_aux_register(&dp->aux);
+	if (ret)
+		goto err_disable_pm_runtime;
 
 	ret = analogix_dp_create_bridge(drm_dev, dp);
 	if (ret) {

drivers/gpu/drm/bridge/analogix/analogix_dp_core.h

···
 #define MAX_CR_LOOP 5
 #define MAX_EQ_LOOP 5
 
-/* I2C EDID Chip ID, Slave Address */
-#define I2C_EDID_DEVICE_ADDR			0x50
-#define I2C_E_EDID_DEVICE_ADDR			0x30
-
-#define EDID_BLOCK_LENGTH			0x80
-#define EDID_HEADER_PATTERN			0x00
-#define EDID_EXTENSION_FLAG			0x7e
-#define EDID_CHECKSUM				0x7f
-
 /* DP_MAX_LANE_COUNT */
 #define DPCD_ENHANCED_FRAME_CAP(x)		(((x) >> 7) & 0x1)
 #define DPCD_MAX_LANE_COUNT(x)			((x) & 0x1f)
···
 	struct drm_device	*drm_dev;
 	struct drm_connector	connector;
 	struct drm_bridge	*bridge;
+	struct drm_dp_aux       aux;
 	struct clk		*clock;
 	unsigned int		irq;
 	void __iomem		*reg_base;
···
 	int			dpms_mode;
 	int			hpd_gpio;
 	bool                    force_hpd;
-	unsigned char           edid[EDID_BLOCK_LENGTH * 2];
 	bool			psr_support;
 
 	struct mutex		panel_lock;
···
 void analogix_dp_init_aux(struct analogix_dp_device *dp);
 int analogix_dp_get_plug_in_status(struct analogix_dp_device *dp);
 void analogix_dp_enable_sw_function(struct analogix_dp_device *dp);
-int analogix_dp_start_aux_transaction(struct analogix_dp_device *dp);
-int analogix_dp_write_byte_to_dpcd(struct analogix_dp_device *dp,
-				   unsigned int reg_addr,
-				   unsigned char data);
-int analogix_dp_read_byte_from_dpcd(struct analogix_dp_device *dp,
-				    unsigned int reg_addr,
-				    unsigned char *data);
-int analogix_dp_write_bytes_to_dpcd(struct analogix_dp_device *dp,
-				    unsigned int reg_addr,
-				    unsigned int count,
-				    unsigned char data[]);
-int analogix_dp_read_bytes_from_dpcd(struct analogix_dp_device *dp,
-				     unsigned int reg_addr,
-				     unsigned int count,
-				     unsigned char data[]);
-int analogix_dp_select_i2c_device(struct analogix_dp_device *dp,
-				  unsigned int device_addr,
-				  unsigned int reg_addr);
-int analogix_dp_read_byte_from_i2c(struct analogix_dp_device *dp,
-				   unsigned int device_addr,
-				   unsigned int reg_addr,
-				   unsigned int *data);
-int analogix_dp_read_bytes_from_i2c(struct analogix_dp_device *dp,
-				    unsigned int device_addr,
-				    unsigned int reg_addr,
-				    unsigned int count,
-				    unsigned char edid[]);
 void analogix_dp_set_link_bandwidth(struct analogix_dp_device *dp, u32 bwtype);
 void analogix_dp_get_link_bandwidth(struct analogix_dp_device *dp, u32 *bwtype);
 void analogix_dp_set_lane_count(struct analogix_dp_device *dp, u32 count);
···
 void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp);
 void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
 			      struct edp_vsc_psr *vsc);
+ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
+			     struct drm_dp_aux_msg *msg);
 
 #endif /* _ANALOGIX_DP_CORE_H */

drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c

···
 	return retval;
 }
 
-int analogix_dp_read_byte_from_dpcd(struct analogix_dp_device *dp,
-				    unsigned int reg_addr,
-				    unsigned char *data)
-{
-	u32 reg;
-	int i;
-	int retval;
-
-	for (i = 0; i < 3; i++) {
-		/* Clear AUX CH data buffer */
-		reg = BUF_CLR;
-		writel(reg, dp->reg_base + ANALOGIX_DP_BUFFER_DATA_CTL);
-
-		/* Select DPCD device address */
-		reg = AUX_ADDR_7_0(reg_addr);
-		writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_7_0);
-		reg = AUX_ADDR_15_8(reg_addr);
-		writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_15_8);
-		reg = AUX_ADDR_19_16(reg_addr);
-		writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_19_16);
-
-		/*
-		 * Set DisplayPort transaction and read 1 byte
-		 * If bit 3 is 1, DisplayPort transaction.
-		 * If Bit 3 is 0, I2C transaction.
-		 */
-		reg = AUX_TX_COMM_DP_TRANSACTION | AUX_TX_COMM_READ;
-		writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_1);
-
-		/* Start AUX transaction */
-		retval = analogix_dp_start_aux_transaction(dp);
-		if (retval == 0)
-			break;
-
-		dev_dbg(dp->dev, "%s: Aux Transaction fail!\n", __func__);
-	}
-
-	/* Read data buffer */
-	reg = readl(dp->reg_base + ANALOGIX_DP_BUF_DATA_0);
-	*data = (unsigned char)(reg & 0xff);
-
-	return retval;
-}
-
-int analogix_dp_write_bytes_to_dpcd(struct analogix_dp_device *dp,
-				    unsigned int reg_addr,
-				    unsigned int count,
-				    unsigned char data[])
-{
-	u32 reg;
-	unsigned int start_offset;
-	unsigned int cur_data_count;
-	unsigned int cur_data_idx;
-	int i;
-	int retval = 0;
-
-	/* Clear AUX CH data buffer */
-	reg = BUF_CLR;
-	writel(reg, dp->reg_base + ANALOGIX_DP_BUFFER_DATA_CTL);
-
-	start_offset = 0;
-	while (start_offset < count) {
-		/* Buffer size of AUX CH is 16 * 4bytes */
-		if ((count - start_offset) > 16)
-			cur_data_count = 16;
-		else
-			cur_data_count = count - start_offset;
-
-		for (i = 0; i < 3; i++) {
-			/* Select DPCD device address */
-			reg = AUX_ADDR_7_0(reg_addr + start_offset);
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_7_0);
-			reg = AUX_ADDR_15_8(reg_addr + start_offset);
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_15_8);
-			reg = AUX_ADDR_19_16(reg_addr + start_offset);
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_19_16);
-
-			for (cur_data_idx = 0; cur_data_idx < cur_data_count;
-			     cur_data_idx++) {
-				reg = data[start_offset + cur_data_idx];
-				writel(reg, dp->reg_base +
-				       ANALOGIX_DP_BUF_DATA_0 +
-				       4 * cur_data_idx);
-			}
-
-			/*
-			 * Set DisplayPort transaction and write
-			 * If bit 3 is 1, DisplayPort transaction.
-			 * If Bit 3 is 0, I2C transaction.
-			 */
-			reg = AUX_LENGTH(cur_data_count) |
-				AUX_TX_COMM_DP_TRANSACTION | AUX_TX_COMM_WRITE;
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_1);
-
-			/* Start AUX transaction */
-			retval = analogix_dp_start_aux_transaction(dp);
-			if (retval == 0)
-				break;
-
-			dev_dbg(dp->dev, "%s: Aux Transaction fail!\n",
-				__func__);
-		}
-
-		start_offset += cur_data_count;
-	}
-
-	return retval;
-}
-
-int analogix_dp_read_bytes_from_dpcd(struct analogix_dp_device *dp,
-				     unsigned int reg_addr,
-				     unsigned int count,
-				     unsigned char data[])
-{
-	u32 reg;
-	unsigned int start_offset;
-	unsigned int cur_data_count;
-	unsigned int cur_data_idx;
-	int i;
-	int retval = 0;
-
-	/* Clear AUX CH data buffer */
-	reg = BUF_CLR;
-	writel(reg, dp->reg_base + ANALOGIX_DP_BUFFER_DATA_CTL);
-
-	start_offset = 0;
-	while (start_offset < count) {
-		/* Buffer size of AUX CH is 16 * 4bytes */
-		if ((count - start_offset) > 16)
-			cur_data_count = 16;
-		else
-			cur_data_count = count - start_offset;
-
-		/* AUX CH Request Transaction process */
-		for (i = 0; i < 3; i++) {
-			/* Select DPCD device address */
-			reg = AUX_ADDR_7_0(reg_addr + start_offset);
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_7_0);
-			reg = AUX_ADDR_15_8(reg_addr + start_offset);
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_15_8);
-			reg = AUX_ADDR_19_16(reg_addr + start_offset);
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_19_16);
-
-			/*
-			 * Set DisplayPort transaction and read
-			 * If bit 3 is 1, DisplayPort transaction.
-			 * If Bit 3 is 0, I2C transaction.
-			 */
-			reg = AUX_LENGTH(cur_data_count) |
-				AUX_TX_COMM_DP_TRANSACTION | AUX_TX_COMM_READ;
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_1);
-
-			/* Start AUX transaction */
-			retval = analogix_dp_start_aux_transaction(dp);
-			if (retval == 0)
-				break;
-
-			dev_dbg(dp->dev, "%s: Aux Transaction fail!\n",
-				__func__);
-		}
-
-		for (cur_data_idx = 0; cur_data_idx < cur_data_count;
-		    cur_data_idx++) {
-			reg = readl(dp->reg_base + ANALOGIX_DP_BUF_DATA_0
-						 + 4 * cur_data_idx);
-			data[start_offset + cur_data_idx] =
-				(unsigned char)reg;
-		}
-
-		start_offset += cur_data_count;
-	}
-
-	return retval;
-}
-
-int analogix_dp_select_i2c_device(struct analogix_dp_device *dp,
-				  unsigned int device_addr,
-				  unsigned int reg_addr)
-{
-	u32 reg;
-	int retval;
-
-	/* Set EDID device address */
-	reg = device_addr;
-	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_7_0);
-	writel(0x0, dp->reg_base + ANALOGIX_DP_AUX_ADDR_15_8);
-	writel(0x0, dp->reg_base + ANALOGIX_DP_AUX_ADDR_19_16);
-
-	/* Set offset from base address of EDID device */
-	writel(reg_addr, dp->reg_base + ANALOGIX_DP_BUF_DATA_0);
-
-	/*
-	 * Set I2C transaction and write address
-	 * If bit 3 is 1, DisplayPort transaction.
-	 * If Bit 3 is 0, I2C transaction.
-	 */
-	reg = AUX_TX_COMM_I2C_TRANSACTION | AUX_TX_COMM_MOT |
-		AUX_TX_COMM_WRITE;
-	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_1);
-
-	/* Start AUX transaction */
-	retval = analogix_dp_start_aux_transaction(dp);
-	if (retval != 0)
-		dev_dbg(dp->dev, "%s: Aux Transaction fail!\n", __func__);
-
-	return retval;
-}
-
-int analogix_dp_read_byte_from_i2c(struct analogix_dp_device *dp,
-				   unsigned int device_addr,
-				   unsigned int reg_addr,
-				   unsigned int *data)
-{
-	u32 reg;
-	int i;
-	int retval;
-
-	for (i = 0; i < 3; i++) {
-		/* Clear AUX CH data buffer */
-		reg = BUF_CLR;
-		writel(reg, dp->reg_base + ANALOGIX_DP_BUFFER_DATA_CTL);
-
-		/* Select EDID device */
-		retval = analogix_dp_select_i2c_device(dp, device_addr,
-						       reg_addr);
-		if (retval != 0)
-			continue;
-
-		/*
-		 * Set I2C transaction and read data
-		 * If bit 3 is 1, DisplayPort transaction.
-		 * If Bit 3 is 0, I2C transaction.
-		 */
-		reg = AUX_TX_COMM_I2C_TRANSACTION |
-			AUX_TX_COMM_READ;
-		writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_1);
-
-		/* Start AUX transaction */
-		retval = analogix_dp_start_aux_transaction(dp);
-		if (retval == 0)
-			break;
-
-		dev_dbg(dp->dev, "%s: Aux Transaction fail!\n", __func__);
-	}
-
-	/* Read data */
-	if (retval == 0)
-		*data = readl(dp->reg_base + ANALOGIX_DP_BUF_DATA_0);
-
-	return retval;
-}
-
-int analogix_dp_read_bytes_from_i2c(struct analogix_dp_device *dp,
-				    unsigned int device_addr,
-				    unsigned int reg_addr,
-				    unsigned int count,
-				    unsigned char edid[])
-{
-	u32 reg;
-	unsigned int i, j;
-	unsigned int cur_data_idx;
-	unsigned int defer = 0;
-	int retval = 0;
-
-	for (i = 0; i < count; i += 16) {
-		for (j = 0; j < 3; j++) {
-			/* Clear AUX CH data buffer */
-			reg = BUF_CLR;
-			writel(reg, dp->reg_base + ANALOGIX_DP_BUFFER_DATA_CTL);
-
-			/* Set normal AUX CH command */
-			reg = readl(dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_2);
-			reg &= ~ADDR_ONLY;
-			writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_2);
-
-			/*
-			 * If Rx sends defer, Tx sends only reads
-			 * request without sending address
-			 */
-			if (!defer)
-				retval = analogix_dp_select_i2c_device(dp,
-						device_addr, reg_addr + i);
-			else
-				defer = 0;
-
-			if (retval == 0) {
-				/*
-				 * Set I2C transaction and write data
-				 * If bit 3 is 1, DisplayPort transaction.
-				 * If Bit 3 is 0, I2C transaction.
-				 */
-				reg = AUX_LENGTH(16) |
-					AUX_TX_COMM_I2C_TRANSACTION |
-					AUX_TX_COMM_READ;
-				writel(reg, dp->reg_base +
-					ANALOGIX_DP_AUX_CH_CTL_1);
-
-				/* Start AUX transaction */
-				retval = analogix_dp_start_aux_transaction(dp);
-				if (retval == 0)
-					break;
-
-				dev_dbg(dp->dev, "%s: Aux Transaction fail!\n",
-					__func__);
-			}
-			/* Check if Rx sends defer */
-			reg = readl(dp->reg_base + ANALOGIX_DP_AUX_RX_COMM);
-			if (reg == AUX_RX_COMM_AUX_DEFER ||
-			    reg == AUX_RX_COMM_I2C_DEFER) {
-				dev_err(dp->dev, "Defer: %d\n\n", reg);
-				defer = 1;
-			}
-		}
-
-		for (cur_data_idx = 0; cur_data_idx < 16; cur_data_idx++) {
-			reg = readl(dp->reg_base + ANALOGIX_DP_BUF_DATA_0
-						 + 4 * cur_data_idx);
-			edid[i + cur_data_idx] = (unsigned char)reg;
-		}
-	}
-
-	return retval;
-}
-
 void analogix_dp_set_link_bandwidth(struct analogix_dp_device *dp, u32 bwtype)
 {
 	u32 reg;
···
 	val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
 	val |= IF_EN;
 	writel(val, dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
+}
+
+ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
+			     struct drm_dp_aux_msg *msg)
+{
+	u32 reg;
+	u8 *buffer = msg->buffer;
+	int timeout_loop = 0;
+	unsigned int i;
+	int num_transferred = 0;
+
+	/* Buffer size of AUX CH is 16 bytes */
+	if (WARN_ON(msg->size > 16))
+		return -E2BIG;
+
+	/* Clear AUX CH data buffer */
+	reg = BUF_CLR;
+	writel(reg, dp->reg_base + ANALOGIX_DP_BUFFER_DATA_CTL);
+
+	switch (msg->request & ~DP_AUX_I2C_MOT) {
+	case DP_AUX_I2C_WRITE:
+		reg = AUX_TX_COMM_WRITE | AUX_TX_COMM_I2C_TRANSACTION;
+		if (msg->request & DP_AUX_I2C_MOT)
+			reg |= AUX_TX_COMM_MOT;
+		break;
+
+	case DP_AUX_I2C_READ:
+		reg = AUX_TX_COMM_READ | AUX_TX_COMM_I2C_TRANSACTION;
+		if (msg->request & DP_AUX_I2C_MOT)
+			reg |= AUX_TX_COMM_MOT;
+		break;
+
+	case DP_AUX_NATIVE_WRITE:
+		reg = AUX_TX_COMM_WRITE | AUX_TX_COMM_DP_TRANSACTION;
+		break;
+
+	case DP_AUX_NATIVE_READ:
+		reg = AUX_TX_COMM_READ | AUX_TX_COMM_DP_TRANSACTION;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	reg |= AUX_LENGTH(msg->size);
+	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_1);
+
+	/* Select DPCD device address */
+	reg = AUX_ADDR_7_0(msg->address);
+	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_7_0);
+	reg = AUX_ADDR_15_8(msg->address);
+	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_15_8);
+	reg = AUX_ADDR_19_16(msg->address);
+	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_ADDR_19_16);
+
+	if (!(msg->request & DP_AUX_I2C_READ)) {
+		for (i = 0; i < msg->size; i++) {
+			reg = buffer[i];
+			writel(reg, dp->reg_base + ANALOGIX_DP_BUF_DATA_0 +
+			       4 * i);
+			num_transferred++;
+		}
+	}
+
+	/* Enable AUX CH operation */
+	reg = AUX_EN;
+
+	/* Zero-sized messages specify address-only transactions. */
+	if (msg->size < 1)
+		reg |= ADDR_ONLY;
+
+	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_2);
+
+	/* Is AUX CH command reply received? */
+	/* TODO: Wait for an interrupt instead of looping? */
+	reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA);
+	while (!(reg & RPLY_RECEIV)) {
+		timeout_loop++;
+		if (timeout_loop > DP_TIMEOUT_LOOP_COUNT) {
+			dev_err(dp->dev, "AUX CH command reply failed!\n");
+			return -ETIMEDOUT;
+		}
+		reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA);
+		usleep_range(10, 11);
+	}
+
+	/* Clear interrupt source for AUX CH command reply */
+	writel(RPLY_RECEIV, dp->reg_base + ANALOGIX_DP_INT_STA);
+
+	/* Clear interrupt source for AUX CH access error */
+	reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA);
+	if (reg & AUX_ERR) {
+		writel(AUX_ERR, dp->reg_base + ANALOGIX_DP_INT_STA);
+		return -EREMOTEIO;
+	}
+
+	/* Check AUX CH error access status */
+	reg = readl(dp->reg_base + ANALOGIX_DP_AUX_CH_STA);
+	if ((reg & AUX_STATUS_MASK)) {
+		dev_err(dp->dev, "AUX CH error happened: %d\n\n",
+			reg & AUX_STATUS_MASK);
+		return -EREMOTEIO;
+	}
+
+	if (msg->request & DP_AUX_I2C_READ) {
+		for (i = 0; i < msg->size; i++) {
+			reg = readl(dp->reg_base + ANALOGIX_DP_BUF_DATA_0 +
+				    4 * i);
+			buffer[i] = (unsigned char)reg;
+			num_transferred++;
+		}
+	}
+
+	/* Check if Rx sends defer */
+	reg = readl(dp->reg_base + ANALOGIX_DP_AUX_RX_COMM);
+	if (reg == AUX_RX_COMM_AUX_DEFER)
+		msg->reply = DP_AUX_NATIVE_REPLY_DEFER;
+	else if (reg == AUX_RX_COMM_I2C_DEFER)
+		msg->reply = DP_AUX_I2C_REPLY_DEFER;
+	else if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_I2C_WRITE ||
+		 (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_I2C_READ)
+		msg->reply = DP_AUX_I2C_REPLY_ACK;
+	else if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_WRITE ||
+		 (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
+		msg->reply = DP_AUX_NATIVE_REPLY_ACK;
+
+	return num_transferred;
 }