1 // SPDX-License-Identifier: GPL-2.0-or-later
7  * (e.g. smbalert) are handled in a separate i2c-smbus module.
9  * All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
16 #include <linux/i2c-smbus.h>
20 #include "i2c-core.h"
42  * i2c_smbus_pec - Incremental CRC8 over the given input data array
59 /* Assume a 7-bit address, which is reasonable for SMBus */
63 	u8 addr = i2c_8bit_addr_from_msg(msg);  in i2c_smbus_msg_pec()  local
64 	pec = i2c_smbus_pec(pec, &addr, 1);  in i2c_smbus_msg_pec()
67 	return i2c_smbus_pec(pec, msg->buf, msg->len);  in i2c_smbus_msg_pec()
73 	msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);  in i2c_smbus_add_pec()
74 	msg->len++;  in i2c_smbus_add_pec()
84 	u8 rpec = msg->buf[--msg->len];  in i2c_smbus_check_pec()
90 		return -EBADMSG;  in i2c_smbus_check_pec()
96  * i2c_smbus_read_byte - SMBus "receive byte" protocol
97  * @client: Handle to slave device
107 	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_read_byte()
115  * i2c_smbus_write_byte - SMBus "send byte" protocol
116  * @client: Handle to slave device
124 	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_write_byte()
130  * i2c_smbus_read_byte_data - SMBus "read byte" protocol
131  * @client: Handle to slave device
132  * @command: Byte interpreted by slave
142 	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_read_byte_data()
150  * i2c_smbus_write_byte_data - SMBus "write byte" protocol
151  * @client: Handle to slave device
152  * @command: Byte interpreted by slave
163 	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_write_byte_data()
170  * i2c_smbus_read_word_data - SMBus "read word" protocol
171  * @client: Handle to slave device
172  * @command: Byte interpreted by slave
175  * else a 16-bit unsigned "word" received from the device.
182 	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_read_word_data()
190  * i2c_smbus_write_word_data - SMBus "write word" protocol
191  * @client: Handle to slave device
192  * @command: Byte interpreted by slave
193  * @value: 16-bit "word" being written
203 	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_write_word_data()
210  * i2c_smbus_read_block_data - SMBus "block read" protocol
211  * @client: Handle to slave device
212  * @command: Byte interpreted by slave
214  *	the data returned by the slave.  SMBus allows at most 32 bytes.
217  * else the number of data bytes in the slave's response.
230 	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_read_block_data()
242  * i2c_smbus_write_block_data - SMBus "block write" protocol
243  * @client: Handle to slave device
244  * @command: Byte interpreted by slave
260 	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_write_block_data()
276 	status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_read_i2c_block_data()
296 	return i2c_smbus_xfer(client->adapter, client->addr, client->flags,  in i2c_smbus_write_i2c_block_data()
304 	bool is_read = msg->flags & I2C_M_RD;  in i2c_smbus_try_get_dmabuf()
311 	msg->buf = dma_buf;  in i2c_smbus_try_get_dmabuf()
312 	msg->flags |= I2C_M_DMA_SAFE;  in i2c_smbus_try_get_dmabuf()
315 		msg->buf[0] = init_val;  in i2c_smbus_try_get_dmabuf()
322 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,  in i2c_smbus_xfer_emulated()  argument
340 			.addr = addr,  in i2c_smbus_xfer_emulated()
345 			.addr = addr,  in i2c_smbus_xfer_emulated()
375 			msgbuf0[1] = data->byte;  in i2c_smbus_xfer_emulated()
383 			msgbuf0[1] = data->word & 0xff;  in i2c_smbus_xfer_emulated()
384 			msgbuf0[2] = data->word >> 8;  in i2c_smbus_xfer_emulated()
392 		msgbuf0[1] = data->word & 0xff;  in i2c_smbus_xfer_emulated()
393 		msgbuf0[2] = data->word >> 8;  in i2c_smbus_xfer_emulated()
402 			msg[0].len = data->block[0] + 2;  in i2c_smbus_xfer_emulated()
404 				dev_err(&adapter->dev,  in i2c_smbus_xfer_emulated()
406 					data->block[0]);  in i2c_smbus_xfer_emulated()
407 				return -EINVAL;  in i2c_smbus_xfer_emulated()
411 			memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);  in i2c_smbus_xfer_emulated()
417 		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {  in i2c_smbus_xfer_emulated()
418 			dev_err(&adapter->dev,  in i2c_smbus_xfer_emulated()
420 				data->block[0]);  in i2c_smbus_xfer_emulated()
421 			return -EINVAL;  in i2c_smbus_xfer_emulated()
424 		msg[0].len = data->block[0] + 2;  in i2c_smbus_xfer_emulated()
426 		memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);  in i2c_smbus_xfer_emulated()
434 		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {  in i2c_smbus_xfer_emulated()
435 			dev_err(&adapter->dev, "Invalid block %s size %d\n",  in i2c_smbus_xfer_emulated()
437 				data->block[0]);  in i2c_smbus_xfer_emulated()
438 			return -EINVAL;  in i2c_smbus_xfer_emulated()
442 			msg[1].len = data->block[0];  in i2c_smbus_xfer_emulated()
445 			msg[0].len = data->block[0] + 1;  in i2c_smbus_xfer_emulated()
448 			memcpy(msg[0].buf + 1, data->block + 1, data->block[0]);  in i2c_smbus_xfer_emulated()
452 		dev_err(&adapter->dev, "Unsupported transaction %d\n", size);  in i2c_smbus_xfer_emulated()
453 		return -EOPNOTSUPP;  in i2c_smbus_xfer_emulated()
465 		if (msg[nmsgs - 1].flags & I2C_M_RD)  in i2c_smbus_xfer_emulated()
466 			msg[nmsgs - 1].len++;  in i2c_smbus_xfer_emulated()
473 		status = -EIO;  in i2c_smbus_xfer_emulated()
479 	if (wants_pec && (msg[nmsgs - 1].flags & I2C_M_RD)) {  in i2c_smbus_xfer_emulated()
480 		status = i2c_smbus_check_pec(partial_pec, &msg[nmsgs - 1]);  in i2c_smbus_xfer_emulated()
488 			data->byte = msgbuf0[0];  in i2c_smbus_xfer_emulated()
491 			data->byte = msgbuf1[0];  in i2c_smbus_xfer_emulated()
495 			data->word = msgbuf1[0] | (msgbuf1[1] << 8);  in i2c_smbus_xfer_emulated()
498 			memcpy(data->block + 1, msg[1].buf, data->block[0]);  in i2c_smbus_xfer_emulated()
503 				dev_err(&adapter->dev,  in i2c_smbus_xfer_emulated()
506 				status = -EPROTO;  in i2c_smbus_xfer_emulated()
509 			memcpy(data->block, msg[1].buf, msg[1].buf[0] + 1);  in i2c_smbus_xfer_emulated()
523  * i2c_smbus_xfer - execute SMBus protocol operations
525  * @addr: Address of SMBus slave on that bus
528  * @command: Byte interpreted by slave, for protocols which use such bytes
535 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,  in i2c_smbus_xfer()  argument
545 	res = __i2c_smbus_xfer(adapter, addr, flags, read_write,  in i2c_smbus_xfer()
553 s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,  in __i2c_smbus_xfer()  argument
557 	int (*xfer_func)(struct i2c_adapter *adap, u16 addr,  in __i2c_smbus_xfer()
571 	trace_smbus_write(adapter, addr, flags, read_write,  in __i2c_smbus_xfer()
573 	trace_smbus_read(adapter, addr, flags, read_write,  in __i2c_smbus_xfer()
578 	xfer_func = adapter->algo->smbus_xfer;  in __i2c_smbus_xfer()
580 		if (adapter->algo->smbus_xfer_atomic)  in __i2c_smbus_xfer()
581 			xfer_func = adapter->algo->smbus_xfer_atomic;  in __i2c_smbus_xfer()
582 		else if (adapter->algo->master_xfer_atomic)  in __i2c_smbus_xfer()
589 		for (res = 0, try = 0; try <= adapter->retries; try++) {  in __i2c_smbus_xfer()
590 			res = xfer_func(adapter, addr, flags, read_write,  in __i2c_smbus_xfer()
592 			if (res != -EAGAIN)  in __i2c_smbus_xfer()
595 				       orig_jiffies + adapter->timeout))  in __i2c_smbus_xfer()
599 		if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)  in __i2c_smbus_xfer()
607 	res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,  in __i2c_smbus_xfer()
612 	trace_smbus_reply(adapter, addr, flags, read_write,  in __i2c_smbus_xfer()
614 	trace_smbus_result(adapter, addr, flags, read_write,  in __i2c_smbus_xfer()
622  * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
623  * @client: Handle to slave device
624  * @command: Byte interpreted by slave
627  *	the data returned by the slave.  SMBus allows at most
634  * The addresses of the I2C slave device that are accessed with this function
636  * effect as a byte read. Before using this function you must double-check
637  * if the I2C slave does support exchanging a block transfer with a byte
649 	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))  in i2c_smbus_read_i2c_block_data_or_emulated()
652 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA))  in i2c_smbus_read_i2c_block_data_or_emulated()
653 		return -EOPNOTSUPP;  in i2c_smbus_read_i2c_block_data_or_emulated()
655 	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) {  in i2c_smbus_read_i2c_block_data_or_emulated()
679  * i2c_new_smbus_alert_device - get ara client for SMBus alert support
708 	struct device *parent = adapter->dev.parent;  in i2c_setup_smbus_alert()
715 	irq = device_property_match_string(parent, "interrupt-names", "smbus_alert");  in i2c_setup_smbus_alert()
716 	if (irq == -EINVAL || irq == -ENODATA)  in i2c_setup_smbus_alert()