mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Andy Shevchenko](/assets/img/avatar_default.png)
An I²C adapter might be instantiated without parent. In such case
there is no property can be retrieved. Skip SMBus alert setup when
this happens.
Fixes: a263a84088
("i2c: smbus: Use device_*() functions instead of of_*()")
Reported-by: syzbot+0591ccf54ee05344e4eb@syzkaller.appspotmail.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
723 lines
20 KiB
C
723 lines
20 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Linux I2C core SMBus and SMBus emulation code
|
|
*
|
|
* This file contains the SMBus functions which are always included in the I2C
|
|
* core because they can be emulated via I2C. SMBus specific extensions
|
|
* (e.g. smbalert) are handled in a separate i2c-smbus module.
|
|
*
|
|
* All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
|
|
* SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
|
|
* Jean Delvare <jdelvare@suse.de>
|
|
*/
|
|
#include <linux/device.h>
|
|
#include <linux/err.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/i2c-smbus.h>
|
|
#include <linux/property.h>
|
|
#include <linux/slab.h>
|
|
|
|
#include "i2c-core.h"
|
|
|
|
#define CREATE_TRACE_POINTS
|
|
#include <trace/events/smbus.h>
|
|
|
|
|
|
/* The SMBus parts */
|
|
|
|
#define POLY (0x1070U << 3)
|
|
static u8 crc8(u16 data)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 8; i++) {
|
|
if (data & 0x8000)
|
|
data = data ^ POLY;
|
|
data = data << 1;
|
|
}
|
|
return (u8)(data >> 8);
|
|
}
|
|
|
|
/**
|
|
* i2c_smbus_pec - Incremental CRC8 over the given input data array
|
|
* @crc: previous return crc8 value
|
|
* @p: pointer to data buffer.
|
|
* @count: number of bytes in data buffer.
|
|
*
|
|
* Incremental CRC8 over count bytes in the array pointed to by p
|
|
*/
|
|
u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < count; i++)
|
|
crc = crc8((crc ^ p[i]) << 8);
|
|
return crc;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_pec);
|
|
|
|
/* Assume a 7-bit address, which is reasonable for SMBus */
|
|
static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
|
|
{
|
|
/* The address will be sent first */
|
|
u8 addr = i2c_8bit_addr_from_msg(msg);
|
|
pec = i2c_smbus_pec(pec, &addr, 1);
|
|
|
|
/* The data buffer follows */
|
|
return i2c_smbus_pec(pec, msg->buf, msg->len);
|
|
}
|
|
|
|
/* Used for write only transactions */
|
|
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
|
|
{
|
|
msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
|
|
msg->len++;
|
|
}
|
|
|
|
/* Return <0 on CRC error
|
|
If there was a write before this read (most cases) we need to take the
|
|
partial CRC from the write part into account.
|
|
Note that this function does modify the message (we need to decrease the
|
|
message length to hide the CRC byte from the caller). */
|
|
static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
|
|
{
|
|
u8 rpec = msg->buf[--msg->len];
|
|
cpec = i2c_smbus_msg_pec(cpec, msg);
|
|
|
|
if (rpec != cpec) {
|
|
pr_debug("Bad PEC 0x%02x vs. 0x%02x\n",
|
|
rpec, cpec);
|
|
return -EBADMSG;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* i2c_smbus_read_byte - SMBus "receive byte" protocol
|
|
* @client: Handle to slave device
|
|
*
|
|
* This executes the SMBus "receive byte" protocol, returning negative errno
|
|
* else the byte received from the device.
|
|
*/
|
|
s32 i2c_smbus_read_byte(const struct i2c_client *client)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, 0,
|
|
I2C_SMBUS_BYTE, &data);
|
|
return (status < 0) ? status : data.byte;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_byte);
|
|
|
|
/**
|
|
* i2c_smbus_write_byte - SMBus "send byte" protocol
|
|
* @client: Handle to slave device
|
|
* @value: Byte to be sent
|
|
*
|
|
* This executes the SMBus "send byte" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
|
|
{
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_byte);
|
|
|
|
/**
|
|
* i2c_smbus_read_byte_data - SMBus "read byte" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
*
|
|
* This executes the SMBus "read byte" protocol, returning negative errno
|
|
* else a data byte received from the device.
|
|
*/
|
|
s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_BYTE_DATA, &data);
|
|
return (status < 0) ? status : data.byte;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
|
|
|
|
/**
|
|
* i2c_smbus_write_byte_data - SMBus "write byte" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @value: Byte being written
|
|
*
|
|
* This executes the SMBus "write byte" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
|
|
u8 value)
|
|
{
|
|
union i2c_smbus_data data;
|
|
data.byte = value;
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_BYTE_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
|
|
|
|
/**
|
|
* i2c_smbus_read_word_data - SMBus "read word" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
*
|
|
* This executes the SMBus "read word" protocol, returning negative errno
|
|
* else a 16-bit unsigned "word" received from the device.
|
|
*/
|
|
s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_WORD_DATA, &data);
|
|
return (status < 0) ? status : data.word;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_word_data);
|
|
|
|
/**
|
|
* i2c_smbus_write_word_data - SMBus "write word" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @value: 16-bit "word" being written
|
|
*
|
|
* This executes the SMBus "write word" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
|
|
u16 value)
|
|
{
|
|
union i2c_smbus_data data;
|
|
data.word = value;
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_WORD_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_word_data);
|
|
|
|
/**
|
|
* i2c_smbus_read_block_data - SMBus "block read" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @values: Byte array into which data will be read; big enough to hold
|
|
* the data returned by the slave. SMBus allows at most 32 bytes.
|
|
*
|
|
* This executes the SMBus "block read" protocol, returning negative errno
|
|
* else the number of data bytes in the slave's response.
|
|
*
|
|
* Note that using this function requires that the client's adapter support
|
|
* the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
|
|
* support this; its emulation through I2C messaging relies on a specific
|
|
* mechanism (I2C_M_RECV_LEN) which may not be implemented.
|
|
*/
|
|
s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
|
|
u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_BLOCK_DATA, &data);
|
|
if (status)
|
|
return status;
|
|
|
|
memcpy(values, &data.block[1], data.block[0]);
|
|
return data.block[0];
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_block_data);
|
|
|
|
/**
|
|
* i2c_smbus_write_block_data - SMBus "block write" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @length: Size of data block; SMBus allows at most 32 bytes
|
|
* @values: Byte array which will be written.
|
|
*
|
|
* This executes the SMBus "block write" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
|
|
u8 length, const u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
|
|
if (length > I2C_SMBUS_BLOCK_MAX)
|
|
length = I2C_SMBUS_BLOCK_MAX;
|
|
data.block[0] = length;
|
|
memcpy(&data.block[1], values, length);
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_BLOCK_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_block_data);
|
|
|
|
/* Returns the number of read bytes */
|
|
s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
|
|
u8 length, u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
if (length > I2C_SMBUS_BLOCK_MAX)
|
|
length = I2C_SMBUS_BLOCK_MAX;
|
|
data.block[0] = length;
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_I2C_BLOCK_DATA, &data);
|
|
if (status < 0)
|
|
return status;
|
|
|
|
memcpy(values, &data.block[1], data.block[0]);
|
|
return data.block[0];
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
|
|
|
|
s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
|
|
u8 length, const u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
|
|
if (length > I2C_SMBUS_BLOCK_MAX)
|
|
length = I2C_SMBUS_BLOCK_MAX;
|
|
data.block[0] = length;
|
|
memcpy(data.block + 1, values, length);
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_I2C_BLOCK_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
|
|
|
|
static void i2c_smbus_try_get_dmabuf(struct i2c_msg *msg, u8 init_val)
|
|
{
|
|
bool is_read = msg->flags & I2C_M_RD;
|
|
unsigned char *dma_buf;
|
|
|
|
dma_buf = kzalloc(I2C_SMBUS_BLOCK_MAX + (is_read ? 2 : 3), GFP_KERNEL);
|
|
if (!dma_buf)
|
|
return;
|
|
|
|
msg->buf = dma_buf;
|
|
msg->flags |= I2C_M_DMA_SAFE;
|
|
|
|
if (init_val)
|
|
msg->buf[0] = init_val;
|
|
}
|
|
|
|
/*
|
|
* Simulate a SMBus command using the I2C protocol.
|
|
* No checking of parameters is done!
|
|
*/
|
|
static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
|
|
unsigned short flags,
|
|
char read_write, u8 command, int size,
|
|
union i2c_smbus_data *data)
|
|
{
|
|
/*
|
|
* So we need to generate a series of msgs. In the case of writing, we
|
|
* need to use only one message; when reading, we need two. We
|
|
* initialize most things with sane defaults, to keep the code below
|
|
* somewhat simpler.
|
|
*/
|
|
unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
|
|
unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
|
|
int nmsgs = read_write == I2C_SMBUS_READ ? 2 : 1;
|
|
u8 partial_pec = 0;
|
|
int status;
|
|
struct i2c_msg msg[2] = {
|
|
{
|
|
.addr = addr,
|
|
.flags = flags,
|
|
.len = 1,
|
|
.buf = msgbuf0,
|
|
}, {
|
|
.addr = addr,
|
|
.flags = flags | I2C_M_RD,
|
|
.len = 0,
|
|
.buf = msgbuf1,
|
|
},
|
|
};
|
|
bool wants_pec = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
|
|
&& size != I2C_SMBUS_I2C_BLOCK_DATA);
|
|
|
|
msgbuf0[0] = command;
|
|
switch (size) {
|
|
case I2C_SMBUS_QUICK:
|
|
msg[0].len = 0;
|
|
/* Special case: The read/write field is used as data */
|
|
msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
|
|
I2C_M_RD : 0);
|
|
nmsgs = 1;
|
|
break;
|
|
case I2C_SMBUS_BYTE:
|
|
if (read_write == I2C_SMBUS_READ) {
|
|
/* Special case: only a read! */
|
|
msg[0].flags = I2C_M_RD | flags;
|
|
nmsgs = 1;
|
|
}
|
|
break;
|
|
case I2C_SMBUS_BYTE_DATA:
|
|
if (read_write == I2C_SMBUS_READ)
|
|
msg[1].len = 1;
|
|
else {
|
|
msg[0].len = 2;
|
|
msgbuf0[1] = data->byte;
|
|
}
|
|
break;
|
|
case I2C_SMBUS_WORD_DATA:
|
|
if (read_write == I2C_SMBUS_READ)
|
|
msg[1].len = 2;
|
|
else {
|
|
msg[0].len = 3;
|
|
msgbuf0[1] = data->word & 0xff;
|
|
msgbuf0[2] = data->word >> 8;
|
|
}
|
|
break;
|
|
case I2C_SMBUS_PROC_CALL:
|
|
nmsgs = 2; /* Special case */
|
|
read_write = I2C_SMBUS_READ;
|
|
msg[0].len = 3;
|
|
msg[1].len = 2;
|
|
msgbuf0[1] = data->word & 0xff;
|
|
msgbuf0[2] = data->word >> 8;
|
|
break;
|
|
case I2C_SMBUS_BLOCK_DATA:
|
|
if (read_write == I2C_SMBUS_READ) {
|
|
msg[1].flags |= I2C_M_RECV_LEN;
|
|
msg[1].len = 1; /* block length will be added by
|
|
the underlying bus driver */
|
|
i2c_smbus_try_get_dmabuf(&msg[1], 0);
|
|
} else {
|
|
msg[0].len = data->block[0] + 2;
|
|
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
|
|
dev_err(&adapter->dev,
|
|
"Invalid block write size %d\n",
|
|
data->block[0]);
|
|
return -EINVAL;
|
|
}
|
|
|
|
i2c_smbus_try_get_dmabuf(&msg[0], command);
|
|
memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);
|
|
}
|
|
break;
|
|
case I2C_SMBUS_BLOCK_PROC_CALL:
|
|
nmsgs = 2; /* Another special case */
|
|
read_write = I2C_SMBUS_READ;
|
|
if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
|
|
dev_err(&adapter->dev,
|
|
"Invalid block write size %d\n",
|
|
data->block[0]);
|
|
return -EINVAL;
|
|
}
|
|
|
|
msg[0].len = data->block[0] + 2;
|
|
i2c_smbus_try_get_dmabuf(&msg[0], command);
|
|
memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);
|
|
|
|
msg[1].flags |= I2C_M_RECV_LEN;
|
|
msg[1].len = 1; /* block length will be added by
|
|
the underlying bus driver */
|
|
i2c_smbus_try_get_dmabuf(&msg[1], 0);
|
|
break;
|
|
case I2C_SMBUS_I2C_BLOCK_DATA:
|
|
if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
|
|
dev_err(&adapter->dev, "Invalid block %s size %d\n",
|
|
read_write == I2C_SMBUS_READ ? "read" : "write",
|
|
data->block[0]);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (read_write == I2C_SMBUS_READ) {
|
|
msg[1].len = data->block[0];
|
|
i2c_smbus_try_get_dmabuf(&msg[1], 0);
|
|
} else {
|
|
msg[0].len = data->block[0] + 1;
|
|
|
|
i2c_smbus_try_get_dmabuf(&msg[0], command);
|
|
memcpy(msg[0].buf + 1, data->block + 1, data->block[0]);
|
|
}
|
|
break;
|
|
default:
|
|
dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
if (wants_pec) {
|
|
/* Compute PEC if first message is a write */
|
|
if (!(msg[0].flags & I2C_M_RD)) {
|
|
if (nmsgs == 1) /* Write only */
|
|
i2c_smbus_add_pec(&msg[0]);
|
|
else /* Write followed by read */
|
|
partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
|
|
}
|
|
/* Ask for PEC if last message is a read */
|
|
if (msg[nmsgs - 1].flags & I2C_M_RD)
|
|
msg[nmsgs - 1].len++;
|
|
}
|
|
|
|
status = __i2c_transfer(adapter, msg, nmsgs);
|
|
if (status < 0)
|
|
goto cleanup;
|
|
if (status != nmsgs) {
|
|
status = -EIO;
|
|
goto cleanup;
|
|
}
|
|
status = 0;
|
|
|
|
/* Check PEC if last message is a read */
|
|
if (wants_pec && (msg[nmsgs - 1].flags & I2C_M_RD)) {
|
|
status = i2c_smbus_check_pec(partial_pec, &msg[nmsgs - 1]);
|
|
if (status < 0)
|
|
goto cleanup;
|
|
}
|
|
|
|
if (read_write == I2C_SMBUS_READ)
|
|
switch (size) {
|
|
case I2C_SMBUS_BYTE:
|
|
data->byte = msgbuf0[0];
|
|
break;
|
|
case I2C_SMBUS_BYTE_DATA:
|
|
data->byte = msgbuf1[0];
|
|
break;
|
|
case I2C_SMBUS_WORD_DATA:
|
|
case I2C_SMBUS_PROC_CALL:
|
|
data->word = msgbuf1[0] | (msgbuf1[1] << 8);
|
|
break;
|
|
case I2C_SMBUS_I2C_BLOCK_DATA:
|
|
memcpy(data->block + 1, msg[1].buf, data->block[0]);
|
|
break;
|
|
case I2C_SMBUS_BLOCK_DATA:
|
|
case I2C_SMBUS_BLOCK_PROC_CALL:
|
|
if (msg[1].buf[0] > I2C_SMBUS_BLOCK_MAX) {
|
|
dev_err(&adapter->dev,
|
|
"Invalid block size returned: %d\n",
|
|
msg[1].buf[0]);
|
|
status = -EPROTO;
|
|
goto cleanup;
|
|
}
|
|
memcpy(data->block, msg[1].buf, msg[1].buf[0] + 1);
|
|
break;
|
|
}
|
|
|
|
cleanup:
|
|
if (msg[0].flags & I2C_M_DMA_SAFE)
|
|
kfree(msg[0].buf);
|
|
if (msg[1].flags & I2C_M_DMA_SAFE)
|
|
kfree(msg[1].buf);
|
|
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* i2c_smbus_xfer - execute SMBus protocol operations
|
|
* @adapter: Handle to I2C bus
|
|
* @addr: Address of SMBus slave on that bus
|
|
* @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
|
|
* @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
|
|
* @command: Byte interpreted by slave, for protocols which use such bytes
|
|
* @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
|
|
* @data: Data to be read or written
|
|
*
|
|
* This executes an SMBus protocol operation, and returns a negative
|
|
* errno code else zero on success.
|
|
*/
|
|
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
|
|
unsigned short flags, char read_write,
|
|
u8 command, int protocol, union i2c_smbus_data *data)
|
|
{
|
|
s32 res;
|
|
|
|
res = __i2c_lock_bus_helper(adapter);
|
|
if (res)
|
|
return res;
|
|
|
|
res = __i2c_smbus_xfer(adapter, addr, flags, read_write,
|
|
command, protocol, data);
|
|
i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
|
|
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_xfer);
|
|
|
|
s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
|
|
unsigned short flags, char read_write,
|
|
u8 command, int protocol, union i2c_smbus_data *data)
|
|
{
|
|
int (*xfer_func)(struct i2c_adapter *adap, u16 addr,
|
|
unsigned short flags, char read_write,
|
|
u8 command, int size, union i2c_smbus_data *data);
|
|
unsigned long orig_jiffies;
|
|
int try;
|
|
s32 res;
|
|
|
|
res = __i2c_check_suspended(adapter);
|
|
if (res)
|
|
return res;
|
|
|
|
/* If enabled, the following two tracepoints are conditional on
|
|
* read_write and protocol.
|
|
*/
|
|
trace_smbus_write(adapter, addr, flags, read_write,
|
|
command, protocol, data);
|
|
trace_smbus_read(adapter, addr, flags, read_write,
|
|
command, protocol);
|
|
|
|
flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
|
|
|
|
xfer_func = adapter->algo->smbus_xfer;
|
|
if (i2c_in_atomic_xfer_mode()) {
|
|
if (adapter->algo->smbus_xfer_atomic)
|
|
xfer_func = adapter->algo->smbus_xfer_atomic;
|
|
else if (adapter->algo->master_xfer_atomic)
|
|
xfer_func = NULL; /* fallback to I2C emulation */
|
|
}
|
|
|
|
if (xfer_func) {
|
|
/* Retry automatically on arbitration loss */
|
|
orig_jiffies = jiffies;
|
|
for (res = 0, try = 0; try <= adapter->retries; try++) {
|
|
res = xfer_func(adapter, addr, flags, read_write,
|
|
command, protocol, data);
|
|
if (res != -EAGAIN)
|
|
break;
|
|
if (time_after(jiffies,
|
|
orig_jiffies + adapter->timeout))
|
|
break;
|
|
}
|
|
|
|
if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
|
|
goto trace;
|
|
/*
|
|
* Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
|
|
* implement native support for the SMBus operation.
|
|
*/
|
|
}
|
|
|
|
res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
|
|
command, protocol, data);
|
|
|
|
trace:
|
|
/* If enabled, the reply tracepoint is conditional on read_write. */
|
|
trace_smbus_reply(adapter, addr, flags, read_write,
|
|
command, protocol, data, res);
|
|
trace_smbus_result(adapter, addr, flags, read_write,
|
|
command, protocol, res);
|
|
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(__i2c_smbus_xfer);
|
|
|
|
/**
|
|
* i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes
|
|
* @values: Byte array into which data will be read; big enough to hold
|
|
* the data returned by the slave. SMBus allows at most
|
|
* I2C_SMBUS_BLOCK_MAX bytes.
|
|
*
|
|
* This executes the SMBus "block read" protocol if supported by the adapter.
|
|
* If block read is not supported, it emulates it using either word or byte
|
|
* read protocols depending on availability.
|
|
*
|
|
* The addresses of the I2C slave device that are accessed with this function
|
|
* must be mapped to a linear region, so that a block read will have the same
|
|
* effect as a byte read. Before using this function you must double-check
|
|
* if the I2C slave does support exchanging a block transfer with a byte
|
|
* transfer.
|
|
*/
|
|
s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
|
|
u8 command, u8 length, u8 *values)
|
|
{
|
|
u8 i = 0;
|
|
int status;
|
|
|
|
if (length > I2C_SMBUS_BLOCK_MAX)
|
|
length = I2C_SMBUS_BLOCK_MAX;
|
|
|
|
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
|
|
return i2c_smbus_read_i2c_block_data(client, command, length, values);
|
|
|
|
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA))
|
|
return -EOPNOTSUPP;
|
|
|
|
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) {
|
|
while ((i + 2) <= length) {
|
|
status = i2c_smbus_read_word_data(client, command + i);
|
|
if (status < 0)
|
|
return status;
|
|
values[i] = status & 0xff;
|
|
values[i + 1] = status >> 8;
|
|
i += 2;
|
|
}
|
|
}
|
|
|
|
while (i < length) {
|
|
status = i2c_smbus_read_byte_data(client, command + i);
|
|
if (status < 0)
|
|
return status;
|
|
values[i] = status;
|
|
i++;
|
|
}
|
|
|
|
return i;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);
|
|
|
|
/**
|
|
* i2c_new_smbus_alert_device - get ara client for SMBus alert support
|
|
* @adapter: the target adapter
|
|
* @setup: setup data for the SMBus alert handler
|
|
* Context: can sleep
|
|
*
|
|
* Setup handling of the SMBus alert protocol on a given I2C bus segment.
|
|
*
|
|
* Handling can be done either through our IRQ handler, or by the
|
|
* adapter (from its handler, periodic polling, or whatever).
|
|
*
|
|
* This returns the ara client, which should be saved for later use with
|
|
* i2c_handle_smbus_alert() and ultimately i2c_unregister_device(); or an
|
|
* ERRPTR to indicate an error.
|
|
*/
|
|
struct i2c_client *i2c_new_smbus_alert_device(struct i2c_adapter *adapter,
|
|
struct i2c_smbus_alert_setup *setup)
|
|
{
|
|
struct i2c_board_info ara_board_info = {
|
|
I2C_BOARD_INFO("smbus_alert", 0x0c),
|
|
.platform_data = setup,
|
|
};
|
|
|
|
return i2c_new_client_device(adapter, &ara_board_info);
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_new_smbus_alert_device);
|
|
|
|
#if IS_ENABLED(CONFIG_I2C_SMBUS)
|
|
int i2c_setup_smbus_alert(struct i2c_adapter *adapter)
|
|
{
|
|
struct device *parent = adapter->dev.parent;
|
|
int irq;
|
|
|
|
/* Adapter instantiated without parent, skip the SMBus alert setup */
|
|
if (!parent)
|
|
return 0;
|
|
|
|
irq = device_property_match_string(parent, "interrupt-names", "smbus_alert");
|
|
if (irq == -EINVAL || irq == -ENODATA)
|
|
return 0;
|
|
else if (irq < 0)
|
|
return irq;
|
|
|
|
return PTR_ERR_OR_ZERO(i2c_new_smbus_alert_device(adapter, NULL));
|
|
}
|
|
#endif
|