* blocks, ...
*/
-/* Run a single AUX_CH I2C transaction, writing/reading data as necessary */
-static int
-i2c_algo_dp_aux_transaction(struct i2c_adapter *adapter, int mode,
- uint8_t write_byte, uint8_t *read_byte)
-{
- struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
- int ret;
-
- ret = (*algo_data->aux_ch)(adapter, mode,
- write_byte, read_byte);
- return ret;
-}
-
-/*
- * I2C over AUX CH
- */
-
-/*
- * Send the address. If the I2C link is running, this 'restarts'
- * the connection with the new address, this is used for doing
- * a write followed by a read (as needed for DDC)
- */
-static int
-i2c_algo_dp_aux_address(struct i2c_adapter *adapter, u16 address, bool reading)
-{
- struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
- int mode = MODE_I2C_START;
- int ret;
-
- if (reading)
- mode |= MODE_I2C_READ;
- else
- mode |= MODE_I2C_WRITE;
- algo_data->address = address;
- algo_data->running = true;
- ret = i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);
- return ret;
-}
-
-/*
- * Stop the I2C transaction. This closes out the link, sending
- * a bare address packet with the MOT bit turned off
- */
-static void
-i2c_algo_dp_aux_stop(struct i2c_adapter *adapter, bool reading)
-{
- struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
- int mode = MODE_I2C_STOP;
-
- if (reading)
- mode |= MODE_I2C_READ;
- else
- mode |= MODE_I2C_WRITE;
- if (algo_data->running) {
- (void) i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);
- algo_data->running = false;
- }
-}
-
-/*
- * Write a single byte to the current I2C address, the
- * the I2C link must be running or this returns -EIO
- */
-static int
-i2c_algo_dp_aux_put_byte(struct i2c_adapter *adapter, u8 byte)
-{
- struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
- int ret;
-
- if (!algo_data->running)
- return -EIO;
-
- ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_WRITE, byte, NULL);
- return ret;
-}
-
-/*
- * Read a single byte from the current I2C address, the
- * I2C link must be running or this returns -EIO
- */
-static int
-i2c_algo_dp_aux_get_byte(struct i2c_adapter *adapter, u8 *byte_ret)
-{
- struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
- int ret;
-
- if (!algo_data->running)
- return -EIO;
-
- ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_READ, 0, byte_ret);
- return ret;
-}
-
-static int
-i2c_algo_dp_aux_xfer(struct i2c_adapter *adapter,
- struct i2c_msg *msgs,
- int num)
-{
- int ret = 0;
- bool reading = false;
- int m;
- int b;
-
- for (m = 0; m < num; m++) {
- u16 len = msgs[m].len;
- u8 *buf = msgs[m].buf;
- reading = (msgs[m].flags & I2C_M_RD) != 0;
- ret = i2c_algo_dp_aux_address(adapter, msgs[m].addr, reading);
- if (ret < 0)
- break;
- if (reading) {
- for (b = 0; b < len; b++) {
- ret = i2c_algo_dp_aux_get_byte(adapter, &buf[b]);
- if (ret < 0)
- break;
- }
- } else {
- for (b = 0; b < len; b++) {
- ret = i2c_algo_dp_aux_put_byte(adapter, buf[b]);
- if (ret < 0)
- break;
- }
- }
- if (ret < 0)
- break;
- }
- if (ret >= 0)
- ret = num;
- i2c_algo_dp_aux_stop(adapter, reading);
- DRM_DEBUG_KMS("dp_aux_xfer return %d\n", ret);
- return ret;
-}
-
-static u32
-i2c_algo_dp_aux_functionality(struct i2c_adapter *adapter)
-{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
- I2C_FUNC_SMBUS_READ_BLOCK_DATA |
- I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
- I2C_FUNC_10BIT_ADDR;
-}
-
-static const struct i2c_algorithm i2c_dp_aux_algo = {
- .master_xfer = i2c_algo_dp_aux_xfer,
- .functionality = i2c_algo_dp_aux_functionality,
-};
-
-static void
-i2c_dp_aux_reset_bus(struct i2c_adapter *adapter)
-{
- (void) i2c_algo_dp_aux_address(adapter, 0, false);
- (void) i2c_algo_dp_aux_stop(adapter, false);
-}
-
-static int
-i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter)
-{
- adapter->algo = &i2c_dp_aux_algo;
- adapter->retries = 3;
- i2c_dp_aux_reset_bus(adapter);
- return 0;
-}
-
-/**
- * i2c_dp_aux_add_bus() - register an i2c adapter using the aux ch helper
- * @adapter: i2c adapter to register
- *
- * This registers an i2c adapter that uses dp aux channel as it's underlaying
- * transport. The driver needs to fill out the &i2c_algo_dp_aux_data structure
- * and store it in the algo_data member of the @adapter argument. This will be
- * used by the i2c over dp aux algorithm to drive the hardware.
- *
- * RETURNS:
- * 0 on success, -ERRNO on failure.
- *
- * IMPORTANT:
- * This interface is deprecated, please switch to the new dp aux helpers and
- * drm_dp_aux_register().
- */
-int
-i2c_dp_aux_add_bus(struct i2c_adapter *adapter)
-{
- int error;
-
- error = i2c_dp_aux_prepare_bus(adapter);
- if (error)
- return error;
- error = i2c_add_adapter(adapter);
- return error;
-}
-EXPORT_SYMBOL(i2c_dp_aux_add_bus);
-
/* Helpers for DP link training */
static u8 dp_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r)
{
/*
* The specification doesn't give any recommendation on how often to
- * retry native transactions, so retry 7 times like for I2C-over-AUX
- * transactions.
+ * retry native transactions. We used to retry 7 times like for
+ * aux i2c transactions but real world devices this wasn't
+ * sufficient, bump to 32 which makes Dell 4k monitors happier.
*/
- for (retry = 0; retry < 7; retry++) {
+ for (retry = 0; retry < 32; retry++) {
mutex_lock(&aux->hw_mutex);
err = aux->transfer(aux, &msg);
case DP_AUX_I2C_REPLY_NACK:
DRM_DEBUG_KMS("I2C nack\n");
+ aux->i2c_nack_count++;
return -EREMOTEIO;
case DP_AUX_I2C_REPLY_DEFER:
DRM_DEBUG_KMS("I2C defer\n");
+ aux->i2c_defer_count++;
usleep_range(400, 500);
continue;
projects / cascardo / linux.git / blobdiff