[PATCH v5 02/10] drm/bridge: it6505: improve AUX operation for edid read

[Hermes Wu]

From: Hermes Wu <Hermes.wu@xxxxxxxxxx>

The original AUX operation using data registers is limited to 4 bytes.
The AUX operation command CMD_AUX_I2C_EDID_READ uses AUX FIFO and is capable of reading 16 bytes.
This improves the speed of EDID read.

Signed-off-by: Hermes Wu <Hermes.wu@xxxxxxxxxx>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 28a8043229d3..864fab7e388f 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -1076,10 +1076,13 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
 				      size_t size, enum aux_cmd_reply *reply)
 {
 	int i, ret_size, ret = 0, request_size;
+	int fifo_max_size = (cmd == CMD_AUX_I2C_EDID_READ) ? AUX_FIFO_MAX_SIZE : 4;
 
 	mutex_lock(&it6505->aux_lock);
-	for (i = 0; i < size; i += 4) {
-		request_size = min((int)size - i, 4);
+	i = 0;
+	do {
+		request_size = min_t(int, (int)size - i, fifo_max_size);
+
 		ret_size = it6505_aux_operation(it6505, cmd, address + i,
 						buffer + i, request_size,
 						reply);
@@ -1088,8 +1091,9 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
 			goto aux_op_err;
 		}
 
+		i += request_size;
 		ret += ret_size;
-	}
+	} while (i < size);
 
 aux_op_err:
 	mutex_unlock(&it6505->aux_lock);
-- 
2.34.1