From 22c78d1cce104072747023d2ae0351bf3f97d725 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Tue, 23 May 2017 12:27:17 +0200 Subject: i2c: break out smbus support into separate file Break out the exported SMBus functions and the emulation layer into a separate file. This also involved splitting up the tracing header into an I2C and an SMBus part. Reviewed-by: Andy Shevchenko Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core-base.c | 574 -------------------------------------------- 1 file changed, 574 deletions(-) (limited to 'drivers/i2c/i2c-core-base.c') diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 88c0ca6..70fc462 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -14,9 +14,6 @@ /* ------------------------------------------------------------------------- */ /* With some changes from Kyösti Mälkki . - All SMBus-related things are written by Frodo Looijaard - SMBus 2.0 support by Mark Studebaker and - Jean Delvare Mux support by Rodolfo Giometti and Michael Lawnick OF support is copyright (c) 2008 Jochen Friedrich @@ -3155,577 +3152,6 @@ void i2c_put_adapter(struct i2c_adapter *adap) } EXPORT_SYMBOL(i2c_put_adapter); -/* 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); -} - -/* Incremental CRC8 over count bytes in the array pointed to by p */ -static 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; -} - -/* 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); - -/* 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 num = read_write == I2C_SMBUS_READ ? 2 : 1; - int i; - 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, - }, - }; - - 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); - num = 1; - break; - case I2C_SMBUS_BYTE: - if (read_write == I2C_SMBUS_READ) { - /* Special case: only a read! */ - msg[0].flags = I2C_M_RD | flags; - num = 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: - num = 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 */ - } 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; - } - for (i = 1; i < msg[0].len; i++) - msgbuf0[i] = data->block[i-1]; - } - break; - case I2C_SMBUS_BLOCK_PROC_CALL: - num = 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; - for (i = 1; i < msg[0].len; i++) - msgbuf0[i] = data->block[i-1]; - msg[1].flags |= I2C_M_RECV_LEN; - msg[1].len = 1; /* block length will be added by - the underlying bus driver */ - break; - case I2C_SMBUS_I2C_BLOCK_DATA: - if (read_write == I2C_SMBUS_READ) { - msg[1].len = data->block[0]; - } else { - msg[0].len = data->block[0] + 1; - if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) { - dev_err(&adapter->dev, - "Invalid block write size %d\n", - data->block[0]); - return -EINVAL; - } - for (i = 1; i <= data->block[0]; i++) - msgbuf0[i] = data->block[i]; - } - break; - default: - dev_err(&adapter->dev, "Unsupported transaction %d\n", size); - return -EOPNOTSUPP; - } - - i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK - && size != I2C_SMBUS_I2C_BLOCK_DATA); - if (i) { - /* Compute PEC if first message is a write */ - if (!(msg[0].flags & I2C_M_RD)) { - if (num == 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[num-1].flags & I2C_M_RD) - msg[num-1].len++; - } - - status = i2c_transfer(adapter, msg, num); - if (status < 0) - return status; - - /* Check PEC if last message is a read */ - if (i && (msg[num-1].flags & I2C_M_RD)) { - status = i2c_smbus_check_pec(partial_pec, &msg[num-1]); - if (status < 0) - return status; - } - - 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: - for (i = 0; i < data->block[0]; i++) - data->block[i+1] = msgbuf1[i]; - break; - case I2C_SMBUS_BLOCK_DATA: - case I2C_SMBUS_BLOCK_PROC_CALL: - for (i = 0; i < msgbuf1[0] + 1; i++) - data->block[i] = msgbuf1[i]; - break; - } - return 0; -} - -/** - * 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) -{ - unsigned long orig_jiffies; - int try; - s32 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; - - if (adapter->algo->smbus_xfer) { - i2c_lock_bus(adapter, I2C_LOCK_SEGMENT); - - /* Retry automatically on arbitration loss */ - orig_jiffies = jiffies; - for (res = 0, try = 0; try <= adapter->retries; try++) { - res = adapter->algo->smbus_xfer(adapter, addr, flags, - read_write, command, - protocol, data); - if (res != -EAGAIN) - break; - if (time_after(jiffies, - orig_jiffies + adapter->timeout)) - break; - } - i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT); - - 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); - 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); - MODULE_AUTHOR("Simon G. Vogl "); MODULE_DESCRIPTION("I2C-Bus main module"); MODULE_LICENSE("GPL"); -- cgit v1.1