drm/amd/display: Right shift AUX reply value sooner than later
authorLeo (Sunpeng) Li <sunpeng.li@amd.com>
Tue, 26 Jun 2018 14:44:05 +0000 (10:44 -0400)
committerAlex Deucher <alexander.deucher@amd.com>
Fri, 13 Jul 2018 19:50:46 +0000 (14:50 -0500)
[Why]
There is no point in keeping the AUX reply value in the raw format as
returned from reading the AUX_SW_DATA register.

[How]
Shift it within read_channel_reply(), where the register is read, before
returning it.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drivers/gpu/drm/amd/display/dc/i2caux/dce110/aux_engine_dce110.c

index 1f3940644a5b061f4b5be2ffcddffa97de0a8dfa..ae5caa97cacaf61049c07c448e9f454976097c9f 100644 (file)
@@ -300,9 +300,10 @@ static int read_channel_reply(struct aux_engine *engine, uint32_t size,
                          AUX_SW_DATA_RW, 1);
 
        REG_GET(AUX_SW_DATA, AUX_SW_DATA, &reply_result_32);
+       reply_result_32 = reply_result_32 >> 4;
        *reply_result = (uint8_t)reply_result_32;
 
-       if (reply_result_32 >> 4 == 0) { /* ACK */
+       if (reply_result_32 == 0) { /* ACK */
                uint32_t i = 0;
 
                /* First byte was already used to get the command status */
@@ -356,7 +357,6 @@ static void process_channel_reply(
                        return;
                }
        } else {
-               reply_result = reply_result >> 4;
 
                switch (reply_result) {
                case 0: /* ACK */