0,0 → 1,209 |
/* |
* Copyright © 2009 Keith Packard |
* |
* Permission to use, copy, modify, distribute, and sell this software and its |
* documentation for any purpose is hereby granted without fee, provided that |
* the above copyright notice appear in all copies and that both that copyright |
* notice and this permission notice appear in supporting documentation, and |
* that the name of the copyright holders not be used in advertising or |
* publicity pertaining to distribution of the software without specific, |
* written prior permission. The copyright holders make no representations |
* about the suitability of this software for any purpose. It is provided "as |
* is" without express or implied warranty. |
* |
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO |
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR |
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, |
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER |
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE |
* OF THIS SOFTWARE. |
*/ |
|
#include <linux/kernel.h> |
#include <linux/module.h> |
//#include <linux/delay.h> |
//#include <linux/slab.h> |
//#include <linux/init.h> |
#include <linux/errno.h> |
#include <linux/sched.h> |
#include <linux/i2c.h> |
#include "drm_dp_helper.h" |
#include "drmP.h" |
|
/* 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; |
} |
|
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); |