linux-kernel - [PATCH v3 1/3] drm/bridge: it6505: fix AUX read use aux fifo

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Message-ID: <20240923094826.13471-2-Hermes.Wu@ite.com.tw>
Date: Mon, 23 Sep 2024 17:48:26 +0800
From: Hermes Wu <Hermes.Wu@....com.tw>
To: Pin-yen Lin <treapking@...omium.org>
CC: Kenneth Hung <Kenneth.hung@....com.tw>, Hermes Wu <Hermes.wu@....com.tw>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong
	<neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart
	<Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej
 Skrabec <jernej.skrabec@...il.com>,
        Maarten Lankhorst
	<maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        "open list:DRM DRIVERS"
	<dri-devel@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: [PATCH v3 1/3] drm/bridge: it6505: fix AUX read use aux fifo

From: Hermes Wu <Hermes.wu@....com.tw>

Changes in v3:
 -New in v3


it6505 AUX FIFO mode only 16 byte.
AUX FIFO mode only supports EDID read and DPCD KSV FIFO area.

Signed-off-by: Hermes Wu <Hermes.wu@....com.tw>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 87b8545fccc0..d8b40ad890bf 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -300,7 +300,7 @@
 #define MAX_CR_LEVEL 0x03
 #define MAX_EQ_LEVEL 0x03
 #define AUX_WAIT_TIMEOUT_MS 15
-#define AUX_FIFO_MAX_SIZE 32
+#define AUX_FIFO_MAX_SIZE 16
 #define PIXEL_CLK_DELAY 1
 #define PIXEL_CLK_INVERSE 0
 #define ADJUST_PHASE_THRESHOLD 80000
@@ -324,8 +324,13 @@ enum aux_cmd_type {
 	CMD_AUX_NATIVE_READ = 0x0,
 	CMD_AUX_NATIVE_WRITE = 0x5,
 	CMD_AUX_I2C_EDID_READ = 0xB,
+
+	/* KSV list read using AUX native read with FIFO */
+	CMD_AUX_GET_KSV_LIST = 0x10,
 };
 
+#define GET_AUX_CONTROL_CODE(cmd) ((cmd) & 0x0F)
+
 enum aux_cmd_reply {
 	REPLY_ACK,
 	REPLY_NACK,
@@ -965,7 +970,8 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
 	it6505_set_bits(it6505, REG_AUX_CTRL, AUX_USER_MODE, AUX_USER_MODE);
 
 aux_op_start:
-	if (cmd == CMD_AUX_I2C_EDID_READ) {
+	/* HW AUX FIFO supports only EDID and DCPD KSV FIFO aread */
+	if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
 		/* AUX EDID FIFO has max length of AUX_FIFO_MAX_SIZE bytes. */
 		size = min_t(size_t, size, AUX_FIFO_MAX_SIZE);
 		/* Enable AUX FIFO read back and clear FIFO */
@@ -996,7 +1002,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
 				  size);
 
 	/* Aux Fire */
-	it6505_write(it6505, REG_AUX_CMD_REQ, cmd);
+	it6505_write(it6505, REG_AUX_CMD_REQ, GET_AUX_CONTROL_CODE(cmd));
 
 	ret = it6505_aux_wait(it6505);
 	if (ret < 0)
@@ -1030,7 +1036,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
 		goto aux_op_start;
 	}
 
-	if (cmd == CMD_AUX_I2C_EDID_READ) {
+	if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
 		for (i = 0; i < size; i++) {
 			ret = it6505_read(it6505, REG_AUX_DATA_FIFO);
 			if (ret < 0)
@@ -1055,7 +1061,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
 	ret = i;
 
 aux_op_err:
-	if (cmd == CMD_AUX_I2C_EDID_READ) {
+	if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST) {
 		/* clear AUX FIFO */
 		it6505_set_bits(it6505, REG_AUX_CTRL,
 				AUX_EN_FIFO_READ | CLR_EDID_FIFO,
@@ -1078,8 +1084,11 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
 	int i, ret_size, ret = 0, request_size;
 
 	mutex_lock(&it6505->aux_lock);
-	for (i = 0; i < size; i += 4) {
-		request_size = min((int)size - i, 4);
+	for (i = 0; i < size; ) {
+		if (cmd == CMD_AUX_I2C_EDID_READ || cmd == CMD_AUX_GET_KSV_LIST)
+			request_size = min_t(int, (int)size - i, AUX_FIFO_MAX_SIZE);
+		else
+			request_size = min_t(int, (int)size - i, 4);
 		ret_size = it6505_aux_operation(it6505, cmd, address + i,
 						buffer + i, request_size,
 						reply);
@@ -1088,6 +1097,7 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
 			goto aux_op_err;
 		}
 
+		i += request_size;
 		ret += ret_size;
 	}
 
@@ -2257,7 +2267,6 @@ static void it6505_link_training_work(struct work_struct *work)
 		it6505->auto_train_retry--;
 		it6505_dump(it6505);
 	}
-
 }
 
 static void it6505_plugged_status_to_codec(struct it6505 *it6505)
-- 
2.34.1