diff options
| author | Alex Deucher <alexdeucher@gmail.com> | 2014-03-18 04:48:17 +0100 |
|---|---|---|
| committer | Christian König <christian.koenig@amd.com> | 2014-03-25 13:13:18 +0100 |
| commit | dca0be0d850363782c46ddc0fb408d658153b4b1 (patch) | |
| tree | a845916ab995e0fea0e992b59edc8d86376ee79c /drivers/gpu/drm/radeon/atombios_dp.c | |
| parent | drm/radeon/atom: rework encoder enable/disable sequence (diff) | |
| download | linux-dca0be0d850363782c46ddc0fb408d658153b4b1.tar.xz linux-dca0be0d850363782c46ddc0fb408d658153b4b1.zip | |
drm/radeon: clarify special handling in i2c over aux
We need a special packet for the start and end of the
transaction.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Diffstat (limited to 'drivers/gpu/drm/radeon/atombios_dp.c')
| -rw-r--r-- | drivers/gpu/drm/radeon/atombios_dp.c | 36 |
1 files changed, 16 insertions, 20 deletions
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index 88d399c3f4fd..23189b796eae 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); |