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719 lines
20 KiB
719 lines
20 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Linux I2C core SMBus and SMBus emulation code |
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* |
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* This file contains the SMBus functions which are always included in the I2C |
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* core because they can be emulated via I2C. SMBus specific extensions |
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* (e.g. smbalert) are handled in a separate i2c-smbus module. |
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* |
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* All SMBus-related things are written by Frodo Looijaard <[email protected]> |
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* SMBus 2.0 support by Mark Studebaker <[email protected]> and |
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* Jean Delvare <[email protected]> |
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*/ |
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#include <linux/device.h> |
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#include <linux/err.h> |
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#include <linux/i2c.h> |
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#include <linux/i2c-smbus.h> |
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#include <linux/slab.h> |
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|
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#include "i2c-core.h" |
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|
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#define CREATE_TRACE_POINTS |
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#include <trace/events/smbus.h> |
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|
|
|
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/* The SMBus parts */ |
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|
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#define POLY (0x1070U << 3) |
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static u8 crc8(u16 data) |
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{ |
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int i; |
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|
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for (i = 0; i < 8; i++) { |
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if (data & 0x8000) |
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data = data ^ POLY; |
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data = data << 1; |
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} |
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return (u8)(data >> 8); |
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} |
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|
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/** |
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* i2c_smbus_pec - Incremental CRC8 over the given input data array |
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* @crc: previous return crc8 value |
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* @p: pointer to data buffer. |
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* @count: number of bytes in data buffer. |
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* |
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* Incremental CRC8 over count bytes in the array pointed to by p |
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*/ |
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u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count) |
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{ |
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int i; |
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|
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for (i = 0; i < count; i++) |
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crc = crc8((crc ^ p[i]) << 8); |
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return crc; |
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} |
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EXPORT_SYMBOL(i2c_smbus_pec); |
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|
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/* Assume a 7-bit address, which is reasonable for SMBus */ |
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static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg) |
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{ |
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/* The address will be sent first */ |
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u8 addr = i2c_8bit_addr_from_msg(msg); |
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pec = i2c_smbus_pec(pec, &addr, 1); |
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|
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/* The data buffer follows */ |
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return i2c_smbus_pec(pec, msg->buf, msg->len); |
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} |
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|
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/* Used for write only transactions */ |
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static inline void i2c_smbus_add_pec(struct i2c_msg *msg) |
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{ |
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msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg); |
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msg->len++; |
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} |
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|
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/* Return <0 on CRC error |
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If there was a write before this read (most cases) we need to take the |
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partial CRC from the write part into account. |
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Note that this function does modify the message (we need to decrease the |
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message length to hide the CRC byte from the caller). */ |
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static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg) |
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{ |
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u8 rpec = msg->buf[--msg->len]; |
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cpec = i2c_smbus_msg_pec(cpec, msg); |
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|
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if (rpec != cpec) { |
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pr_debug("Bad PEC 0x%02x vs. 0x%02x\n", |
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rpec, cpec); |
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return -EBADMSG; |
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} |
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return 0; |
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} |
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|
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/** |
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* i2c_smbus_read_byte - SMBus "receive byte" protocol |
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* @client: Handle to slave device |
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* |
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* This executes the SMBus "receive byte" protocol, returning negative errno |
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* else the byte received from the device. |
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*/ |
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s32 i2c_smbus_read_byte(const struct i2c_client *client) |
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{ |
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union i2c_smbus_data data; |
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int status; |
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|
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status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_READ, 0, |
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I2C_SMBUS_BYTE, &data); |
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return (status < 0) ? status : data.byte; |
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} |
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EXPORT_SYMBOL(i2c_smbus_read_byte); |
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|
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/** |
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* i2c_smbus_write_byte - SMBus "send byte" protocol |
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* @client: Handle to slave device |
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* @value: Byte to be sent |
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* |
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* This executes the SMBus "send byte" protocol, returning negative errno |
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* else zero on success. |
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*/ |
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s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value) |
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{ |
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return i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL); |
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} |
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EXPORT_SYMBOL(i2c_smbus_write_byte); |
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|
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/** |
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* i2c_smbus_read_byte_data - SMBus "read byte" protocol |
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* @client: Handle to slave device |
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* @command: Byte interpreted by slave |
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* |
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* This executes the SMBus "read byte" protocol, returning negative errno |
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* else a data byte received from the device. |
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*/ |
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s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command) |
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{ |
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union i2c_smbus_data data; |
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int status; |
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|
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status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_READ, command, |
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I2C_SMBUS_BYTE_DATA, &data); |
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return (status < 0) ? status : data.byte; |
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} |
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EXPORT_SYMBOL(i2c_smbus_read_byte_data); |
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|
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/** |
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* i2c_smbus_write_byte_data - SMBus "write byte" protocol |
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* @client: Handle to slave device |
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* @command: Byte interpreted by slave |
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* @value: Byte being written |
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* |
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* This executes the SMBus "write byte" protocol, returning negative errno |
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* else zero on success. |
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*/ |
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s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command, |
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u8 value) |
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{ |
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union i2c_smbus_data data; |
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data.byte = value; |
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return i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_WRITE, command, |
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I2C_SMBUS_BYTE_DATA, &data); |
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} |
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EXPORT_SYMBOL(i2c_smbus_write_byte_data); |
|
|
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/** |
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* i2c_smbus_read_word_data - SMBus "read word" protocol |
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* @client: Handle to slave device |
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* @command: Byte interpreted by slave |
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* |
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* This executes the SMBus "read word" protocol, returning negative errno |
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* else a 16-bit unsigned "word" received from the device. |
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*/ |
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s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command) |
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{ |
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union i2c_smbus_data data; |
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int status; |
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|
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status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_READ, command, |
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I2C_SMBUS_WORD_DATA, &data); |
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return (status < 0) ? status : data.word; |
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} |
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EXPORT_SYMBOL(i2c_smbus_read_word_data); |
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|
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/** |
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* i2c_smbus_write_word_data - SMBus "write word" protocol |
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* @client: Handle to slave device |
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* @command: Byte interpreted by slave |
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* @value: 16-bit "word" being written |
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* |
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* This executes the SMBus "write word" protocol, returning negative errno |
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* else zero on success. |
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*/ |
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s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command, |
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u16 value) |
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{ |
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union i2c_smbus_data data; |
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data.word = value; |
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return i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_WRITE, command, |
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I2C_SMBUS_WORD_DATA, &data); |
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} |
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EXPORT_SYMBOL(i2c_smbus_write_word_data); |
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|
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/** |
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* i2c_smbus_read_block_data - SMBus "block read" protocol |
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* @client: Handle to slave device |
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* @command: Byte interpreted by slave |
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* @values: Byte array into which data will be read; big enough to hold |
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* the data returned by the slave. SMBus allows at most 32 bytes. |
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* |
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* This executes the SMBus "block read" protocol, returning negative errno |
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* else the number of data bytes in the slave's response. |
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* |
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* Note that using this function requires that the client's adapter support |
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* the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers |
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* support this; its emulation through I2C messaging relies on a specific |
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* mechanism (I2C_M_RECV_LEN) which may not be implemented. |
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*/ |
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s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command, |
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u8 *values) |
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{ |
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union i2c_smbus_data data; |
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int status; |
|
|
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status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_READ, command, |
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I2C_SMBUS_BLOCK_DATA, &data); |
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if (status) |
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return status; |
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|
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memcpy(values, &data.block[1], data.block[0]); |
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return data.block[0]; |
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} |
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EXPORT_SYMBOL(i2c_smbus_read_block_data); |
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|
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/** |
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* i2c_smbus_write_block_data - SMBus "block write" protocol |
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* @client: Handle to slave device |
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* @command: Byte interpreted by slave |
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* @length: Size of data block; SMBus allows at most 32 bytes |
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* @values: Byte array which will be written. |
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* |
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* This executes the SMBus "block write" protocol, returning negative errno |
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* else zero on success. |
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*/ |
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s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command, |
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u8 length, const u8 *values) |
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{ |
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union i2c_smbus_data data; |
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|
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if (length > I2C_SMBUS_BLOCK_MAX) |
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length = I2C_SMBUS_BLOCK_MAX; |
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data.block[0] = length; |
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memcpy(&data.block[1], values, length); |
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return i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_WRITE, command, |
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I2C_SMBUS_BLOCK_DATA, &data); |
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} |
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EXPORT_SYMBOL(i2c_smbus_write_block_data); |
|
|
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/* Returns the number of read bytes */ |
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s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command, |
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u8 length, u8 *values) |
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{ |
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union i2c_smbus_data data; |
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int status; |
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|
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if (length > I2C_SMBUS_BLOCK_MAX) |
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length = I2C_SMBUS_BLOCK_MAX; |
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data.block[0] = length; |
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status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_READ, command, |
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I2C_SMBUS_I2C_BLOCK_DATA, &data); |
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if (status < 0) |
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return status; |
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|
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memcpy(values, &data.block[1], data.block[0]); |
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return data.block[0]; |
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} |
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EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data); |
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|
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s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command, |
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u8 length, const u8 *values) |
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{ |
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union i2c_smbus_data data; |
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|
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if (length > I2C_SMBUS_BLOCK_MAX) |
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length = I2C_SMBUS_BLOCK_MAX; |
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data.block[0] = length; |
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memcpy(data.block + 1, values, length); |
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return i2c_smbus_xfer(client->adapter, client->addr, client->flags, |
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I2C_SMBUS_WRITE, command, |
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I2C_SMBUS_I2C_BLOCK_DATA, &data); |
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} |
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EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data); |
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|
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static void i2c_smbus_try_get_dmabuf(struct i2c_msg *msg, u8 init_val) |
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{ |
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bool is_read = msg->flags & I2C_M_RD; |
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unsigned char *dma_buf; |
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|
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dma_buf = kzalloc(I2C_SMBUS_BLOCK_MAX + (is_read ? 2 : 3), GFP_KERNEL); |
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if (!dma_buf) |
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return; |
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|
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msg->buf = dma_buf; |
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msg->flags |= I2C_M_DMA_SAFE; |
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|
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if (init_val) |
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msg->buf[0] = init_val; |
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} |
|
|
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/* |
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* Simulate a SMBus command using the I2C protocol. |
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* No checking of parameters is done! |
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*/ |
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static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, |
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unsigned short flags, |
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char read_write, u8 command, int size, |
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union i2c_smbus_data *data) |
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{ |
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/* |
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* So we need to generate a series of msgs. In the case of writing, we |
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* need to use only one message; when reading, we need two. We |
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* initialize most things with sane defaults, to keep the code below |
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* somewhat simpler. |
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*/ |
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unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3]; |
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unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2]; |
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int nmsgs = read_write == I2C_SMBUS_READ ? 2 : 1; |
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u8 partial_pec = 0; |
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int status; |
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struct i2c_msg msg[2] = { |
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{ |
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.addr = addr, |
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.flags = flags, |
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.len = 1, |
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.buf = msgbuf0, |
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}, { |
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.addr = addr, |
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.flags = flags | I2C_M_RD, |
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.len = 0, |
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.buf = msgbuf1, |
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}, |
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}; |
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bool wants_pec = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK |
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&& size != I2C_SMBUS_I2C_BLOCK_DATA); |
|
|
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msgbuf0[0] = command; |
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switch (size) { |
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case I2C_SMBUS_QUICK: |
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msg[0].len = 0; |
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/* Special case: The read/write field is used as data */ |
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msg[0].flags = flags | (read_write == I2C_SMBUS_READ ? |
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I2C_M_RD : 0); |
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nmsgs = 1; |
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break; |
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case I2C_SMBUS_BYTE: |
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if (read_write == I2C_SMBUS_READ) { |
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/* Special case: only a read! */ |
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msg[0].flags = I2C_M_RD | flags; |
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nmsgs = 1; |
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} |
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break; |
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case I2C_SMBUS_BYTE_DATA: |
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if (read_write == I2C_SMBUS_READ) |
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msg[1].len = 1; |
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else { |
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msg[0].len = 2; |
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msgbuf0[1] = data->byte; |
|
} |
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break; |
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case I2C_SMBUS_WORD_DATA: |
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if (read_write == I2C_SMBUS_READ) |
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msg[1].len = 2; |
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else { |
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msg[0].len = 3; |
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msgbuf0[1] = data->word & 0xff; |
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msgbuf0[2] = data->word >> 8; |
|
} |
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break; |
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case I2C_SMBUS_PROC_CALL: |
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nmsgs = 2; /* Special case */ |
|
read_write = I2C_SMBUS_READ; |
|
msg[0].len = 3; |
|
msg[1].len = 2; |
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msgbuf0[1] = data->word & 0xff; |
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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 */ |
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i2c_smbus_try_get_dmabuf(&msg[1], 0); |
|
} else { |
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msg[0].len = data->block[0] + 2; |
|
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) { |
|
dev_err(&adapter->dev, |
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"Invalid block write size %d\n", |
|
data->block[0]); |
|
return -EINVAL; |
|
} |
|
|
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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) && IS_ENABLED(CONFIG_OF) |
|
int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter) |
|
{ |
|
int irq; |
|
|
|
irq = of_property_match_string(adapter->dev.of_node, "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)); |
|
} |
|
EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert); |
|
#endif
|
|
|