diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 43 |
1 files changed, 39 insertions, 4 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 80a02a412607..5a55d905b8ee 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -422,6 +422,19 @@ static u32 drm_dp_i2c_functionality(struct i2c_adapter *adapter) I2C_FUNC_10BIT_ADDR; } +static void drm_dp_i2c_msg_write_status_update(struct drm_dp_aux_msg *msg) +{ + /* + * In case of i2c defer or short i2c ack reply to a write, + * we need to switch to WRITE_STATUS_UPDATE to drain the + * rest of the message + */ + if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_I2C_WRITE) { + msg->request &= DP_AUX_I2C_MOT; + msg->request |= DP_AUX_I2C_WRITE_STATUS_UPDATE; + } +} + /* * Transfer a single I2C-over-AUX message and handle various error conditions, * retrying the transaction as appropriate. It is assumed that the @@ -490,6 +503,8 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) * Both native ACK and I2C ACK replies received. We * can assume the transfer was successful. */ + if (ret != msg->size) + drm_dp_i2c_msg_write_status_update(msg); return ret; case DP_AUX_I2C_REPLY_NACK: @@ -507,6 +522,7 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) if (defer_i2c < 7) defer_i2c++; usleep_range(400, 500); + drm_dp_i2c_msg_write_status_update(msg); continue; default: @@ -519,6 +535,14 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) return -EREMOTEIO; } +static void drm_dp_i2c_msg_set_request(struct drm_dp_aux_msg *msg, + const struct i2c_msg *i2c_msg) +{ + msg->request = (i2c_msg->flags & I2C_M_RD) ? + DP_AUX_I2C_READ : DP_AUX_I2C_WRITE; + msg->request |= DP_AUX_I2C_MOT; +} + /* * Keep retrying drm_dp_i2c_do_msg until all data has been transferred. * @@ -572,10 +596,7 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, for (i = 0; i < num; i++) { msg.address = msgs[i].addr; - msg.request = (msgs[i].flags & I2C_M_RD) ? - DP_AUX_I2C_READ : - DP_AUX_I2C_WRITE; - msg.request |= DP_AUX_I2C_MOT; + drm_dp_i2c_msg_set_request(&msg, &msgs[i]); /* Send a bare address packet to start the transaction. * Zero sized messages specify an address only (bare * address) transaction. @@ -583,6 +604,13 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, msg.buffer = NULL; msg.size = 0; err = drm_dp_i2c_do_msg(aux, &msg); + + /* + * Reset msg.request in case in case it got + * changed into a WRITE_STATUS_UPDATE. + */ + drm_dp_i2c_msg_set_request(&msg, &msgs[i]); + if (err < 0) break; /* We want each transaction to be as large as possible, but @@ -595,6 +623,13 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, msg.size = min(transfer_size, msgs[i].len - j); err = drm_dp_i2c_drain_msg(aux, &msg); + + /* + * Reset msg.request in case in case it got + * changed into a WRITE_STATUS_UPDATE. + */ + drm_dp_i2c_msg_set_request(&msg, &msgs[i]); + if (err < 0) break; transfer_size = err; |