[PATCH v4 04/11] drm/bridge: it6505: fix aux command write to aux operaction register

[Hermes Wu]

From: Hermes Wu <Hermes.wu at ite.com.tw>

The aux control register command is 4 bits LSB only, adding a MACRO to get
correct operaction command.

Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
Signed-off-by: Hermes Wu <Hermes.wu at ite.com.tw>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 0583abdca75f..d1f5220e04a6 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -329,6 +329,8 @@ enum aux_cmd_type {
 	CMD_AUX_GET_KSV_LIST = 0x10,
 };
 
+#define GET_AUX_CONTROL_CODE(cmd) ((cmd) & 0x0F)
+
 enum aux_cmd_reply {
 	REPLY_ACK,
 	REPLY_NACK,
@@ -1000,7 +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)
-- 
2.34.1