We need a special packet for the start and end of the
transaction.
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/gpu/drm/radeon/atombios_dp.c | 36 ++++++++++++++++--------------------
1 file changed, 16 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 88d399c..23189b7 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -246,34 +246,30 @@ int radeon_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
int ret;
u8 ack;
- /* Set up the command byte */
- if (mode & MODE_I2C_READ)
- msg[2] = DP_AUX_I2C_READ << 4;
- else
- msg[2] = DP_AUX_I2C_WRITE << 4;
-
- if (!(mode & MODE_I2C_STOP))
- msg[2] |= DP_AUX_I2C_MOT << 4;
-
+ /* Set up the address */
msg[0] = address;
msg[1] = address >> 8;
- switch (mode) {
- case MODE_I2C_WRITE:
+ /* Set up the command byte */
+ if (mode & MODE_I2C_READ) {
+ msg[2] = DP_AUX_I2C_READ << 4;
+ msg_bytes = 4;
+ msg[3] = msg_bytes << 4;
+ } else {
+ msg[2] = DP_AUX_I2C_WRITE << 4;
msg_bytes = 5;
msg[3] = msg_bytes << 4;
msg[4] = write_byte;
- break;
- case MODE_I2C_READ:
- msg_bytes = 4;
- msg[3] = msg_bytes << 4;
- break;
- default:
- msg_bytes = 4;
- msg[3] = 3 << 4;
- break;
}
+ /* special handling for start/stop */
+ if (mode & (MODE_I2C_START | MODE_I2C_STOP))
+ msg[3] = 3 << 4;
+
+ /* Set MOT bit for all but stop */
+ if ((mode & MODE_I2C_STOP) == 0)
+ msg[2] |= DP_AUX_I2C_MOT << 4;
+
for (retry = 0; retry < 7; retry++) {
ret = radeon_process_aux_ch(auxch,
msg, msg_bytes, reply, reply_bytes, 0, &ack);
--
1.8.3.1
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