Merge branch 'drm-next-3.15-wip' of git://people.freedesktop.org/~deathsimple/linux into drm-next

Some i2c fixes over DisplayPort.

* 'drm-next-3.15-wip' of git://people.freedesktop.org/~deathsimple/linux:
  drm/radeon: Improve vramlimit module param documentation
  drm/radeon: fix audio pin counts for DCE6+ (v2)
  drm/radeon/dp: switch to the common i2c over aux code
  drm/dp/i2c: Update comments about common i2c over dp assumptions (v3)
  drm/dp/i2c: send bare addresses to properly reset i2c connections (v4)
  drm/radeon/dp: handle zero sized i2c over aux transactions (v2)
  drm/i915: support address only i2c-over-aux transactions
  drm/tegra: dp: Support address-only I2C-over-AUX transactions

12 files changed, 148 insertions, 247 deletions

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 27671489477d..4b6e6f3ba0a1 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -577,7 +577,9 @@ static u32 drm_dp_i2c_functionality(struct i2c_adapter *adapter)
 
 /*
  * Transfer a single I2C-over-AUX message and handle various error conditions,
- * retrying the transaction as appropriate.
+ * retrying the transaction as appropriate.  It is assumed that the
+ * aux->transfer function does not modify anything in the msg other than the
+ * reply field.
  */
 static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 {
@@ -665,11 +667,26 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 {
         struct drm_dp_aux *aux = adapter->algo_data;
         unsigned int i, j;
+        struct drm_dp_aux_msg msg;
+        int err = 0;
 
-        for (i = 0; i < num; i++) {
-                struct drm_dp_aux_msg msg;
-                int err;
+        memset(&msg, 0, sizeof(msg));
 
+        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;
+                /* Send a bare address packet to start the transaction.
+                 * Zero sized messages specify an address only (bare
+                 * address) transaction.
+                 */
+                msg.buffer = NULL;
+                msg.size = 0;
+                err = drm_dp_i2c_do_msg(aux, &msg);
+                if (err < 0)
+                        break;
                 /*
                  * Many hardware implementations support FIFOs larger than a
                  * single byte, but it has been empirically determined that
@@ -678,30 +695,28 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
                  * transferred byte-by-byte.
                  */
                 for (j = 0; j < msgs[i].len; j++) {
-                        memset(&msg, 0, sizeof(msg));
-                        msg.address = msgs[i].addr;
-
-                        msg.request = (msgs[i].flags & I2C_M_RD) ?
-                                        DP_AUX_I2C_READ :
-                                        DP_AUX_I2C_WRITE;
-
-                        /*
-                         * All messages except the last one are middle-of-
-                         * transfer messages.
-                         */
-                        if ((i < num - 1) || (j < msgs[i].len - 1))
-                                msg.request |= DP_AUX_I2C_MOT;
-
                         msg.buffer = msgs[i].buf + j;
                         msg.size = 1;
 
                         err = drm_dp_i2c_do_msg(aux, &msg);
                         if (err < 0)
-                                return err;
+                                break;
                 }
+                if (err < 0)
+                        break;
         }
+        if (err >= 0)
+                err = num;
+        /* Send a bare address packet to close out the transaction.
+         * Zero sized messages specify an address only (bare
+         * address) transaction.
+         */
+        msg.request &= ~DP_AUX_I2C_MOT;
+        msg.buffer = NULL;
+        msg.size = 0;
+        (void)drm_dp_i2c_do_msg(aux, &msg);
 
-        return num;
+        return err;
 }
 
 static const struct i2c_algorithm drm_dp_i2c_algo = {
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a0dad1a2f819..d2a55884ad52 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -575,7 +575,8 @@ out:
         return ret;
 }
 
-#define HEADER_SIZE     4
+#define BARE_ADDRESS_SIZE       3
+#define HEADER_SIZE             (BARE_ADDRESS_SIZE + 1)
 static ssize_t
 intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 {
@@ -592,7 +593,7 @@ intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
         switch (msg->request & ~DP_AUX_I2C_MOT) {
         case DP_AUX_NATIVE_WRITE:
         case DP_AUX_I2C_WRITE:
-                txsize = HEADER_SIZE + msg->size;
+                txsize = msg->size ? HEADER_SIZE + msg->size : BARE_ADDRESS_SIZE;
                 rxsize = 1;
 
                 if (WARN_ON(txsize > 20))
@@ -611,7 +612,7 @@ intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 
         case DP_AUX_NATIVE_READ:
         case DP_AUX_I2C_READ:
-                txsize = HEADER_SIZE;
+                txsize = msg->size ? HEADER_SIZE : BARE_ADDRESS_SIZE;
                 rxsize = msg->size + 1;
 
                 if (WARN_ON(rxsize > 20))
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 8b0ab170cef9..15936524f226 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -142,7 +142,8 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan,
         return recv_bytes;
 }
 
-#define HEADER_SIZE 4
+#define BARE_ADDRESS_SIZE 3
+#define HEADER_SIZE (BARE_ADDRESS_SIZE + 1)
 
 static ssize_t
 radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
@@ -160,13 +161,19 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
         tx_buf[0] = msg->address & 0xff;
         tx_buf[1] = msg->address >> 8;
         tx_buf[2] = msg->request << 4;
-        tx_buf[3] = msg->size - 1;
+        tx_buf[3] = msg->size ? (msg->size - 1) : 0;
 
         switch (msg->request & ~DP_AUX_I2C_MOT) {
         case DP_AUX_NATIVE_WRITE:
         case DP_AUX_I2C_WRITE:
+                /* tx_size needs to be 4 even for bare address packets since the atom
+                 * table needs the info in tx_buf[3].
+                 */
                 tx_size = HEADER_SIZE + msg->size;
-                tx_buf[3] |= tx_size << 4;
+                if (msg->size == 0)
+                        tx_buf[3] |= BARE_ADDRESS_SIZE << 4;
+                else
+                        tx_buf[3] |= tx_size << 4;
                 memcpy(tx_buf + HEADER_SIZE, msg->buffer, msg->size);
                 ret = radeon_process_aux_ch(chan,
                                             tx_buf, tx_size, NULL, 0, delay, &ack);
@@ -176,8 +183,14 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
                 break;
         case DP_AUX_NATIVE_READ:
         case DP_AUX_I2C_READ:
+                /* tx_size needs to be 4 even for bare address packets since the atom
+                 * table needs the info in tx_buf[3].
+                 */
                 tx_size = HEADER_SIZE;
-                tx_buf[3] |= tx_size << 4;
+                if (msg->size == 0)
+                        tx_buf[3] |= BARE_ADDRESS_SIZE << 4;
+                else
+                        tx_buf[3] |= tx_size << 4;
                 ret = radeon_process_aux_ch(chan,
                                             tx_buf, tx_size, msg->buffer, msg->size, delay, &ack);
                 break;
@@ -186,7 +199,7 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
                 break;
         }
 
-        if (ret > 0)
+        if (ret >= 0)
                 msg->reply = ack >> 4;
 
         return ret;
@@ -194,98 +207,15 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 
 void radeon_dp_aux_init(struct radeon_connector *radeon_connector)
 {
-        struct radeon_connector_atom_dig *dig_connector = radeon_connector->con_priv;
-
-        dig_connector->dp_i2c_bus->aux.dev = radeon_connector->base.kdev;
-        dig_connector->dp_i2c_bus->aux.transfer = radeon_dp_aux_transfer;
-}
-
-int radeon_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
-                         u8 write_byte, u8 *read_byte)
-{
-        struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
-        struct radeon_i2c_chan *auxch = i2c_get_adapdata(adapter);
-        u16 address = algo_data->address;
-        u8 msg[5];
-        u8 reply[2];
-        unsigned retry;
-        int msg_bytes;
-        int reply_bytes = 1;
         int ret;
-        u8 ack;
-
-        /* Set up the address */
-        msg[0] = address;
-        msg[1] = address >> 8;
-
-        /* 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;
-        }
-
-        /* 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);
-                if (ret == -EBUSY)
-                        continue;
-                else if (ret < 0) {
-                        DRM_DEBUG_KMS("aux_ch failed %d\n", ret);
-                        return ret;
-                }
-
-                switch ((ack >> 4) & DP_AUX_NATIVE_REPLY_MASK) {
-                case DP_AUX_NATIVE_REPLY_ACK:
-                        /* I2C-over-AUX Reply field is only valid
-                         * when paired with AUX ACK.
-                         */
-                        break;
-                case DP_AUX_NATIVE_REPLY_NACK:
-                        DRM_DEBUG_KMS("aux_ch native nack\n");
-                        return -EREMOTEIO;
-                case DP_AUX_NATIVE_REPLY_DEFER:
-                        DRM_DEBUG_KMS("aux_ch native defer\n");
-                        usleep_range(500, 600);
-                        continue;
-                default:
-                        DRM_ERROR("aux_ch invalid native reply 0x%02x\n", ack);
-                        return -EREMOTEIO;
-                }
 
-                switch ((ack >> 4) & DP_AUX_I2C_REPLY_MASK) {
-                case DP_AUX_I2C_REPLY_ACK:
-                        if (mode == MODE_I2C_READ)
-                                *read_byte = reply[0];
-                        return ret;
-                case DP_AUX_I2C_REPLY_NACK:
-                        DRM_DEBUG_KMS("aux_i2c nack\n");
-                        return -EREMOTEIO;
-                case DP_AUX_I2C_REPLY_DEFER:
-                        DRM_DEBUG_KMS("aux_i2c defer\n");
-                        usleep_range(400, 500);
-                        break;
-                default:
-                        DRM_ERROR("aux_i2c invalid reply 0x%02x\n", ack);
-                        return -EREMOTEIO;
-                }
-        }
+        radeon_connector->ddc_bus->aux.dev = radeon_connector->base.kdev;
+        radeon_connector->ddc_bus->aux.transfer = radeon_dp_aux_transfer;
+        ret = drm_dp_aux_register_i2c_bus(&radeon_connector->ddc_bus->aux);
+        if (!ret)
+                radeon_connector->ddc_bus->has_aux = true;
 
-        DRM_DEBUG_KMS("aux i2c too many retries, giving up\n");
-        return -EREMOTEIO;
+        WARN(ret, "drm_dp_aux_register_i2c_bus() failed with error %d\n", ret);
 }
 
 /***** general DP utility functions *****/
@@ -420,12 +350,11 @@ static u8 radeon_dp_encoder_service(struct radeon_device *rdev,
 
 u8 radeon_dp_getsinktype(struct radeon_connector *radeon_connector)
 {
-        struct radeon_connector_atom_dig *dig_connector = radeon_connector->con_priv;
         struct drm_device *dev = radeon_connector->base.dev;
         struct radeon_device *rdev = dev->dev_private;
 
         return radeon_dp_encoder_service(rdev, ATOM_DP_ACTION_GET_SINK_TYPE, 0,
-                                         dig_connector->dp_i2c_bus->rec.i2c_id, 0);
+                                         radeon_connector->ddc_bus->rec.i2c_id, 0);
 }
 
 static void radeon_dp_probe_oui(struct radeon_connector *radeon_connector)
@@ -436,11 +365,11 @@ static void radeon_dp_probe_oui(struct radeon_connector *radeon_connector)
         if (!(dig_connector->dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_OUI_SUPPORT))
                 return;
 
-        if (drm_dp_dpcd_read(&dig_connector->dp_i2c_bus->aux, DP_SINK_OUI, buf, 3))
+        if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_SINK_OUI, buf, 3))
                 DRM_DEBUG_KMS("Sink OUI: %02hx%02hx%02hx\n",
                               buf[0], buf[1], buf[2]);
 
-        if (drm_dp_dpcd_read(&dig_connector->dp_i2c_bus->aux, DP_BRANCH_OUI, buf, 3))
+        if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_BRANCH_OUI, buf, 3))
                 DRM_DEBUG_KMS("Branch OUI: %02hx%02hx%02hx\n",
                               buf[0], buf[1], buf[2]);
 }
@@ -451,7 +380,7 @@ bool radeon_dp_getdpcd(struct radeon_connector *radeon_connector)
         u8 msg[DP_DPCD_SIZE];
         int ret, i;
 
-        ret = drm_dp_dpcd_read(&dig_connector->dp_i2c_bus->aux, DP_DPCD_REV, msg,
+        ret = drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_DPCD_REV, msg,
                                DP_DPCD_SIZE);
         if (ret > 0) {
                 memcpy(dig_connector->dpcd, msg, DP_DPCD_SIZE);
@@ -489,7 +418,7 @@ int radeon_dp_get_panel_mode(struct drm_encoder *encoder,
 
         if (dp_bridge != ENCODER_OBJECT_ID_NONE) {
                 /* DP bridge chips */
-                drm_dp_dpcd_readb(&dig_connector->dp_i2c_bus->aux,
+                drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
                                   DP_EDP_CONFIGURATION_CAP, &tmp);
                 if (tmp & 1)
                         panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE;
@@ -500,7 +429,7 @@ int radeon_dp_get_panel_mode(struct drm_encoder *encoder,
                         panel_mode = DP_PANEL_MODE_EXTERNAL_DP_MODE;
         } else if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
                 /* eDP */
-                drm_dp_dpcd_readb(&dig_connector->dp_i2c_bus->aux,
+                drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux,
                                   DP_EDP_CONFIGURATION_CAP, &tmp);
                 if (tmp & 1)
                         panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE;
@@ -554,7 +483,8 @@ bool radeon_dp_needs_link_train(struct radeon_connector *radeon_connector)
         u8 link_status[DP_LINK_STATUS_SIZE];
         struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
 
-        if (drm_dp_dpcd_read_link_status(&dig->dp_i2c_bus->aux, link_status) <= 0)
+        if (drm_dp_dpcd_read_link_status(&radeon_connector->ddc_bus->aux, link_status)
+            <= 0)
                 return false;
         if (drm_dp_channel_eq_ok(link_status, dig->dp_lane_count))
                 return false;
@@ -574,7 +504,7 @@ void radeon_dp_set_rx_power_state(struct drm_connector *connector,
 
         /* power up/down the sink */
         if (dig_connector->dpcd[0] >= 0x11) {
-                drm_dp_dpcd_writeb(&dig_connector->dp_i2c_bus->aux,
+                drm_dp_dpcd_writeb(&radeon_connector->ddc_bus->aux,
                                    DP_SET_POWER, power_state);
                 usleep_range(1000, 2000);
         }
@@ -878,7 +808,7 @@ void radeon_dp_link_train(struct drm_encoder *encoder,
         else
                 dp_info.enc_id |= ATOM_DP_CONFIG_LINK_A;
 
-        drm_dp_dpcd_readb(&dig_connector->dp_i2c_bus->aux, DP_MAX_LANE_COUNT, &tmp);
+        drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux, DP_MAX_LANE_COUNT, &tmp);
         if (ASIC_IS_DCE5(rdev) && (tmp & DP_TPS3_SUPPORTED))
                 dp_info.tp3_supported = true;
         else
@@ -890,7 +820,7 @@ void radeon_dp_link_train(struct drm_encoder *encoder,
         dp_info.connector = connector;
         dp_info.dp_lane_count = dig_connector->dp_lane_count;
         dp_info.dp_clock = dig_connector->dp_clock;
-        dp_info.aux = &dig_connector->dp_i2c_bus->aux;
+        dp_info.aux = &radeon_connector->ddc_bus->aux;
 
         if (radeon_dp_link_train_init(&dp_info))
                 goto done;
diff --git a/drivers/gpu/drm/radeon/dce6_afmt.c b/drivers/gpu/drm/radeon/dce6_afmt.c
index 94e858751994..0a65dc7e93e7 100644
--- a/drivers/gpu/drm/radeon/dce6_afmt.c
+++ b/drivers/gpu/drm/radeon/dce6_afmt.c
@@ -309,11 +309,17 @@ int dce6_audio_init(struct radeon_device *rdev)
 
         rdev->audio.enabled = true;
 
-        if (ASIC_IS_DCE8(rdev))
+        if (ASIC_IS_DCE81(rdev)) /* KV: 4 streams, 7 endpoints */
+                rdev->audio.num_pins = 7;
+        else if (ASIC_IS_DCE83(rdev)) /* KB: 2 streams, 3 endpoints */
+                rdev->audio.num_pins = 3;
+        else if (ASIC_IS_DCE8(rdev)) /* BN/HW: 6 streams, 7 endpoints */
+                rdev->audio.num_pins = 7;
+        else if (ASIC_IS_DCE61(rdev)) /* TN: 4 streams, 6 endpoints */
                 rdev->audio.num_pins = 6;
-        else if (ASIC_IS_DCE61(rdev))
-                rdev->audio.num_pins = 4;
-        else
+        else if (ASIC_IS_DCE64(rdev)) /* OL: 2 streams, 2 endpoints */
+                rdev->audio.num_pins = 2;
+        else /* SI: 6 streams, 6 endpoints */
                 rdev->audio.num_pins = 6;
 
         for (i = 0; i < rdev->audio.num_pins; i++) {
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 7014bdd688ce..b58e1afdda76 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -739,7 +739,7 @@ union radeon_irq_stat_regs {
         struct cik_irq_stat_regs cik;
 };
 
-#define RADEON_MAX_HPD_PINS 6
+#define RADEON_MAX_HPD_PINS 7
 #define RADEON_MAX_CRTCS 6
 #define RADEON_MAX_AFMT_BLOCKS 7
 
@@ -2632,6 +2632,9 @@ void r100_pll_errata_after_index(struct radeon_device *rdev);
 #define ASIC_IS_DCE64(rdev) ((rdev->family == CHIP_OLAND))
 #define ASIC_IS_NODCE(rdev) ((rdev->family == CHIP_HAINAN))
 #define ASIC_IS_DCE8(rdev) ((rdev->family >= CHIP_BONAIRE))
+#define ASIC_IS_DCE81(rdev) ((rdev->family == CHIP_KAVERI))
+#define ASIC_IS_DCE82(rdev) ((rdev->family == CHIP_BONAIRE))
+#define ASIC_IS_DCE83(rdev) ((rdev->family == CHIP_KABINI))
 
 #define ASIC_IS_LOMBOK(rdev) ((rdev->ddev->pdev->device == 0x6849) || \
                               (rdev->ddev->pdev->device == 0x6850) || \
diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index c566b486ca08..ea50e0ae7bf7 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -1261,21 +1261,6 @@ static const struct drm_connector_funcs radeon_dvi_connector_funcs = {
         .force = radeon_dvi_force,
 };
 
-static void radeon_dp_connector_destroy(struct drm_connector *connector)
-{
-        struct radeon_connector *radeon_connector = to_radeon_connector(connector);
-        struct radeon_connector_atom_dig *radeon_dig_connector = radeon_connector->con_priv;
-
-        if (radeon_connector->edid)
-                kfree(radeon_connector->edid);
-        if (radeon_dig_connector->dp_i2c_bus)
-                radeon_i2c_destroy(radeon_dig_connector->dp_i2c_bus);
-        kfree(radeon_connector->con_priv);
-        drm_sysfs_connector_remove(connector);
-        drm_connector_cleanup(connector);
-        kfree(connector);
-}
-
 static int radeon_dp_get_modes(struct drm_connector *connector)
 {
         struct radeon_connector *radeon_connector = to_radeon_connector(connector);
@@ -1553,7 +1538,7 @@ static const struct drm_connector_funcs radeon_dp_connector_funcs = {
         .detect = radeon_dp_detect,
         .fill_modes = drm_helper_probe_single_connector_modes,
         .set_property = radeon_connector_set_property,
-        .destroy = radeon_dp_connector_destroy,
+        .destroy = radeon_connector_destroy,
         .force = radeon_dvi_force,
 };
 
@@ -1562,7 +1547,7 @@ static const struct drm_connector_funcs radeon_edp_connector_funcs = {
         .detect = radeon_dp_detect,
         .fill_modes = drm_helper_probe_single_connector_modes,
         .set_property = radeon_lvds_set_property,
-        .destroy = radeon_dp_connector_destroy,
+        .destroy = radeon_connector_destroy,
         .force = radeon_dvi_force,
 };
 
@@ -1571,7 +1556,7 @@ static const struct drm_connector_funcs radeon_lvds_bridge_connector_funcs = {
         .detect = radeon_dp_detect,
         .fill_modes = drm_helper_probe_single_connector_modes,
         .set_property = radeon_lvds_set_property,
-        .destroy = radeon_dp_connector_destroy,
+        .destroy = radeon_connector_destroy,
         .force = radeon_dvi_force,
 };
 
@@ -1668,17 +1653,10 @@ radeon_add_atom_connector(struct drm_device *dev,
                 radeon_dig_connector->igp_lane_info = igp_lane_info;
                 radeon_connector->con_priv = radeon_dig_connector;
                 if (i2c_bus->valid) {
-                        /* add DP i2c bus */
-                        if (connector_type == DRM_MODE_CONNECTOR_eDP)
-                                radeon_dig_connector->dp_i2c_bus = radeon_i2c_create_dp(dev, i2c_bus, "eDP-auxch");
-                        else
-                                radeon_dig_connector->dp_i2c_bus = radeon_i2c_create_dp(dev, i2c_bus, "DP-auxch");
-                        if (radeon_dig_connector->dp_i2c_bus)
+                        radeon_connector->ddc_bus = radeon_i2c_lookup(rdev, i2c_bus);
+                        if (radeon_connector->ddc_bus)
                                 has_aux = true;
                         else
-                                DRM_ERROR("DP: Failed to assign dp ddc bus! Check dmesg for i2c errors.\n");
-                        radeon_connector->ddc_bus = radeon_i2c_lookup(rdev, i2c_bus);
-                        if (!radeon_connector->ddc_bus)
                                 DRM_ERROR("DP: Failed to assign ddc bus! Check dmesg for i2c errors.\n");
                 }
                 switch (connector_type) {
@@ -1893,10 +1871,6 @@ radeon_add_atom_connector(struct drm_device *dev,
                         drm_connector_init(dev, &radeon_connector->base, &radeon_dp_connector_funcs, connector_type);
                         drm_connector_helper_add(&radeon_connector->base, &radeon_dp_connector_helper_funcs);
                         if (i2c_bus->valid) {
-                                /* add DP i2c bus */
-                                radeon_dig_connector->dp_i2c_bus = radeon_i2c_create_dp(dev, i2c_bus, "DP-auxch");
-                                if (!radeon_dig_connector->dp_i2c_bus)
-                                        DRM_ERROR("DP: Failed to assign dp ddc bus! Check dmesg for i2c errors.\n");
                                 radeon_connector->ddc_bus = radeon_i2c_lookup(rdev, i2c_bus);
                                 if (radeon_connector->ddc_bus)
                                         has_aux = true;
@@ -1942,14 +1916,10 @@ radeon_add_atom_connector(struct drm_device *dev,
                         drm_connector_init(dev, &radeon_connector->base, &radeon_edp_connector_funcs, connector_type);
                         drm_connector_helper_add(&radeon_connector->base, &radeon_dp_connector_helper_funcs);
                         if (i2c_bus->valid) {
-                                /* add DP i2c bus */
-                                radeon_dig_connector->dp_i2c_bus = radeon_i2c_create_dp(dev, i2c_bus, "eDP-auxch");
-                                if (radeon_dig_connector->dp_i2c_bus)
+                                radeon_connector->ddc_bus = radeon_i2c_lookup(rdev, i2c_bus);
+                                if (radeon_connector->ddc_bus)
                                         has_aux = true;
                                 else
-                                        DRM_ERROR("DP: Failed to assign dp ddc bus! Check dmesg for i2c errors.\n");
-                                radeon_connector->ddc_bus = radeon_i2c_lookup(rdev, i2c_bus);
-                                if (!radeon_connector->ddc_bus)
                                         DRM_ERROR("DP: Failed to assign ddc bus! Check dmesg for i2c errors.\n");
                         }
                         drm_object_attach_property(&radeon_connector->base.base,
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 063d4255137f..2f7cbb901fb1 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -759,19 +759,18 @@ int radeon_ddc_get_modes(struct radeon_connector *radeon_connector)
 
         if (radeon_connector_encoder_get_dp_bridge_encoder_id(&radeon_connector->base) !=
             ENCODER_OBJECT_ID_NONE) {
-                struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
-
-                if (dig->dp_i2c_bus)
+                if (radeon_connector->ddc_bus->has_aux)
                         radeon_connector->edid = drm_get_edid(&radeon_connector->base,
-                                                              &dig->dp_i2c_bus->adapter);
+                                                              &radeon_connector->ddc_bus->aux.ddc);
         } else if ((radeon_connector->base.connector_type == DRM_MODE_CONNECTOR_DisplayPort) ||
                    (radeon_connector->base.connector_type == DRM_MODE_CONNECTOR_eDP)) {
                 struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
 
                 if ((dig->dp_sink_type == CONNECTOR_OBJECT_ID_DISPLAYPORT ||
-                     dig->dp_sink_type == CONNECTOR_OBJECT_ID_eDP) && dig->dp_i2c_bus)
+                     dig->dp_sink_type == CONNECTOR_OBJECT_ID_eDP) &&
+                    radeon_connector->ddc_bus->has_aux)
                         radeon_connector->edid = drm_get_edid(&radeon_connector->base,
-                                                              &dig->dp_i2c_bus->adapter);
+                                                              &radeon_connector->ddc_bus->aux.ddc);
                 else if (radeon_connector->ddc_bus && !radeon_connector->edid)
                         radeon_connector->edid = drm_get_edid(&radeon_connector->base,
                                                               &radeon_connector->ddc_bus->adapter);
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 25127ba44ed9..c00a2f585185 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -185,7 +185,7 @@ module_param_named(dynclks, radeon_dynclks, int, 0444);
 MODULE_PARM_DESC(r4xx_atom, "Enable ATOMBIOS modesetting for R4xx");
 module_param_named(r4xx_atom, radeon_r4xx_atom, int, 0444);
 
-MODULE_PARM_DESC(vramlimit, "Restrict VRAM for testing");
+MODULE_PARM_DESC(vramlimit, "Restrict VRAM for testing, in megabytes");
 module_param_named(vramlimit, radeon_vram_limit, int, 0600);
 
 MODULE_PARM_DESC(agpmode, "AGP Mode (-1 == PCI)");
diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index e24ca6ab96de..7b944142a9fd 100644
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -64,8 +64,7 @@ bool radeon_ddc_probe(struct radeon_connector *radeon_connector, bool use_aux)
                 radeon_router_select_ddc_port(radeon_connector);
 
         if (use_aux) {
-                struct radeon_connector_atom_dig *dig = radeon_connector->con_priv;
-                ret = i2c_transfer(&dig->dp_i2c_bus->adapter, msgs, 2);
+                ret = i2c_transfer(&radeon_connector->ddc_bus->aux.ddc, msgs, 2);
         } else {
                 ret = i2c_transfer(&radeon_connector->ddc_bus->adapter, msgs, 2);
         }
@@ -950,16 +949,16 @@ struct radeon_i2c_chan *radeon_i2c_create(struct drm_device *dev,
                 /* set the radeon bit adapter */
                 snprintf(i2c->adapter.name, sizeof(i2c->adapter.name),
                          "Radeon i2c bit bus %s", name);
-                i2c->adapter.algo_data = &i2c->algo.bit;
-                i2c->algo.bit.pre_xfer = pre_xfer;
-                i2c->algo.bit.post_xfer = post_xfer;
-                i2c->algo.bit.setsda = set_data;
-                i2c->algo.bit.setscl = set_clock;
-                i2c->algo.bit.getsda = get_data;
-                i2c->algo.bit.getscl = get_clock;
-                i2c->algo.bit.udelay = 10;
-                i2c->algo.bit.timeout = usecs_to_jiffies(2200); /* from VESA */
-                i2c->algo.bit.data = i2c;
+                i2c->adapter.algo_data = &i2c->bit;
+                i2c->bit.pre_xfer = pre_xfer;
+                i2c->bit.post_xfer = post_xfer;
+                i2c->bit.setsda = set_data;
+                i2c->bit.setscl = set_clock;
+                i2c->bit.getsda = get_data;
+                i2c->bit.getscl = get_clock;
+                i2c->bit.udelay = 10;
+                i2c->bit.timeout = usecs_to_jiffies(2200);      /* from VESA */
+                i2c->bit.data = i2c;
                 ret = i2c_bit_add_bus(&i2c->adapter);
                 if (ret) {
                         DRM_ERROR("Failed to register bit i2c %s\n", name);
@@ -974,46 +973,13 @@ out_free:
 
 }
 
-struct radeon_i2c_chan *radeon_i2c_create_dp(struct drm_device *dev,
-                                             struct radeon_i2c_bus_rec *rec,
-                                             const char *name)
-{
-        struct radeon_i2c_chan *i2c;
-        int ret;
-
-        i2c = kzalloc(sizeof(struct radeon_i2c_chan), GFP_KERNEL);
-        if (i2c == NULL)
-                return NULL;
-
-        i2c->rec = *rec;
-        i2c->adapter.owner = THIS_MODULE;
-        i2c->adapter.class = I2C_CLASS_DDC;
-        i2c->adapter.dev.parent = &dev->pdev->dev;
-        i2c->dev = dev;
-        snprintf(i2c->adapter.name, sizeof(i2c->adapter.name),
-                 "Radeon aux bus %s", name);
-        i2c_set_adapdata(&i2c->adapter, i2c);
-        i2c->adapter.algo_data = &i2c->algo.dp;
-        i2c->algo.dp.aux_ch = radeon_dp_i2c_aux_ch;
-        i2c->algo.dp.address = 0;
-        ret = i2c_dp_aux_add_bus(&i2c->adapter);
-        if (ret) {
-                DRM_INFO("Failed to register i2c %s\n", name);
-                goto out_free;
-        }
-
-        return i2c;
-out_free:
-        kfree(i2c);
-        return NULL;
-
-}
-
 void radeon_i2c_destroy(struct radeon_i2c_chan *i2c)
 {
         if (!i2c)
                 return;
         i2c_del_adapter(&i2c->adapter);
+        if (i2c->has_aux)
+                drm_dp_aux_unregister_i2c_bus(&i2c->aux);
         kfree(i2c);
 }
 
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 832d9fa1a4c4..6ddf31a2d34e 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -187,12 +187,10 @@ struct radeon_pll {
 struct radeon_i2c_chan {
         struct i2c_adapter adapter;
         struct drm_device *dev;
-        union {
-                struct i2c_algo_bit_data bit;
-                struct i2c_algo_dp_aux_data dp;
-        } algo;
+        struct i2c_algo_bit_data bit;
         struct radeon_i2c_bus_rec rec;
         struct drm_dp_aux aux;
+        bool has_aux;
 };
 
 /* mostly for macs, but really any system without connector tables */
@@ -440,7 +438,6 @@ struct radeon_encoder {
 struct radeon_connector_atom_dig {
         uint32_t igp_lane_info;
         /* displayport */
-        struct radeon_i2c_chan *dp_i2c_bus;
         u8 dpcd[DP_RECEIVER_CAP_SIZE];
         u8 dp_sink_type;
         int dp_clock;
@@ -702,8 +699,6 @@ extern void atombios_dig_transmitter_setup(struct drm_encoder *encoder,
                                            uint8_t lane_set);
 extern void radeon_atom_ext_encoder_setup_ddc(struct drm_encoder *encoder);
 extern struct drm_encoder *radeon_get_external_encoder(struct drm_encoder *encoder);
-extern int radeon_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
-                                u8 write_byte, u8 *read_byte);
 void radeon_atom_copy_swap(u8 *dst, u8 *src, u8 num_bytes, bool to_le);
 
 extern void radeon_i2c_init(struct radeon_device *rdev);
@@ -715,9 +710,6 @@ extern void radeon_i2c_add(struct radeon_device *rdev,
                            const char *name);
 extern struct radeon_i2c_chan *radeon_i2c_lookup(struct radeon_device *rdev,
                                                  struct radeon_i2c_bus_rec *i2c_bus);
-extern struct radeon_i2c_chan *radeon_i2c_create_dp(struct drm_device *dev,
-                                                    struct radeon_i2c_bus_rec *rec,
-                                                    const char *name);
 extern struct radeon_i2c_chan *radeon_i2c_create(struct drm_device *dev,
                                                  struct radeon_i2c_bus_rec *rec,
                                                  const char *name);
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index d536ed381fbd..005c19bd92df 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -99,55 +99,73 @@ static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer,
 static ssize_t tegra_dpaux_transfer(struct drm_dp_aux *aux,
                                     struct drm_dp_aux_msg *msg)
 {
-        unsigned long value = DPAUX_DP_AUXCTL_TRANSACTREQ;
         unsigned long timeout = msecs_to_jiffies(250);
         struct tegra_dpaux *dpaux = to_dpaux(aux);
         unsigned long status;
         ssize_t ret = 0;
+        u32 value;
 
-        if (msg->size < 1 || msg->size > 16)
+        /* Tegra has 4x4 byte DP AUX transmit and receive FIFOs. */
+        if (msg->size > 16)
                 return -EINVAL;
 
-        tegra_dpaux_writel(dpaux, msg->address, DPAUX_DP_AUXADDR);
+        /*
+         * Allow zero-sized messages only for I2C, in which case they specify
+         * address-only transactions.
+         */
+        if (msg->size < 1) {
+                switch (msg->request & ~DP_AUX_I2C_MOT) {
+                case DP_AUX_I2C_WRITE:
+                case DP_AUX_I2C_READ:
+                        value = DPAUX_DP_AUXCTL_CMD_ADDRESS_ONLY;
+                        break;
+
+                default:
+                        return -EINVAL;
+                }
+        } else {
+                /* For non-zero-sized messages, set the CMDLEN field. */
+                value = DPAUX_DP_AUXCTL_CMDLEN(msg->size - 1);
+        }
 
         switch (msg->request & ~DP_AUX_I2C_MOT) {
         case DP_AUX_I2C_WRITE:
                 if (msg->request & DP_AUX_I2C_MOT)
-                        value = DPAUX_DP_AUXCTL_CMD_MOT_WR;
+                        value |= DPAUX_DP_AUXCTL_CMD_MOT_WR;
                 else
-                        value = DPAUX_DP_AUXCTL_CMD_I2C_WR;
+                        value |= DPAUX_DP_AUXCTL_CMD_I2C_WR;
 
                 break;
 
         case DP_AUX_I2C_READ:
                 if (msg->request & DP_AUX_I2C_MOT)
-                        value = DPAUX_DP_AUXCTL_CMD_MOT_RD;
+                        value |= DPAUX_DP_AUXCTL_CMD_MOT_RD;
                 else
-                        value = DPAUX_DP_AUXCTL_CMD_I2C_RD;
+                        value |= DPAUX_DP_AUXCTL_CMD_I2C_RD;
 
                 break;
 
         case DP_AUX_I2C_STATUS:
                 if (msg->request & DP_AUX_I2C_MOT)
-                        value = DPAUX_DP_AUXCTL_CMD_MOT_RQ;
+                        value |= DPAUX_DP_AUXCTL_CMD_MOT_RQ;
                 else
-                        value = DPAUX_DP_AUXCTL_CMD_I2C_RQ;
+                        value |= DPAUX_DP_AUXCTL_CMD_I2C_RQ;
 
                 break;
 
         case DP_AUX_NATIVE_WRITE:
-                value = DPAUX_DP_AUXCTL_CMD_AUX_WR;
+                value |= DPAUX_DP_AUXCTL_CMD_AUX_WR;
                 break;
 
         case DP_AUX_NATIVE_READ:
-                value = DPAUX_DP_AUXCTL_CMD_AUX_RD;
+                value |= DPAUX_DP_AUXCTL_CMD_AUX_RD;
                 break;
 
         default:
                 return -EINVAL;
         }
 
-        value |= DPAUX_DP_AUXCTL_CMDLEN(msg->size - 1);
+        tegra_dpaux_writel(dpaux, msg->address, DPAUX_DP_AUXADDR);
         tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXCTL);
 
         if ((msg->request & DP_AUX_I2C_READ) == 0) {
@@ -198,7 +216,7 @@ static ssize_t tegra_dpaux_transfer(struct drm_dp_aux *aux,
                 break;
         }
 
-        if (msg->reply == DP_AUX_NATIVE_REPLY_ACK) {
+        if ((msg->size > 0) && (msg->reply == DP_AUX_NATIVE_REPLY_ACK)) {
                 if (msg->request & DP_AUX_I2C_READ) {
                         size_t count = value & DPAUX_DP_AUXSTAT_REPLY_MASK;
 
diff --git a/drivers/gpu/drm/tegra/dpaux.h b/drivers/gpu/drm/tegra/dpaux.h
index 4f5bf10fdff9..806e245ca787 100644
--- a/drivers/gpu/drm/tegra/dpaux.h
+++ b/drivers/gpu/drm/tegra/dpaux.h
@@ -32,6 +32,7 @@
 #define DPAUX_DP_AUXCTL_CMD_I2C_RQ (2 << 12)
 #define DPAUX_DP_AUXCTL_CMD_I2C_RD (1 << 12)
 #define DPAUX_DP_AUXCTL_CMD_I2C_WR (0 << 12)
+#define DPAUX_DP_AUXCTL_CMD_ADDRESS_ONLY (1 << 8)
 #define DPAUX_DP_AUXCTL_CMDLEN(x) ((x) & 0xff)
 
 #define DPAUX_DP_AUXSTAT 0x31