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@@ -0,0 +1,594 @@
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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 seperate i2c-smbus module.
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+ *
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+ * All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
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+ * SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
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+ * Jean Delvare <jdelvare@suse.de>
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+ *
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+ * This program is free software; you can redistribute it and/or modify it
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+ * under the terms of the GNU General Public License as published by the Free
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+ * Software Foundation; either version 2 of the License, or (at your option)
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+ * any later version.
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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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+
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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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+
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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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+/* Incremental CRC8 over count bytes in the array pointed to by p */
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+static 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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+
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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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+/**
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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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+
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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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+
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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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+/* Simulate a SMBus command using the i2c protocol
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+ No checking of parameters is done! */
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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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+ /* 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 initialize
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+ most things with sane defaults, to keep the code below somewhat
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+ simpler. */
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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 num = read_write == I2C_SMBUS_READ ? 2 : 1;
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+ int i;
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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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+
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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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+ num = 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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+ num = 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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+ }
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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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+ }
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+ break;
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+ case I2C_SMBUS_PROC_CALL:
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+ num = 2; /* Special case */
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+ read_write = I2C_SMBUS_READ;
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+ msg[0].len = 3;
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+ msg[1].len = 2;
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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_BLOCK_DATA:
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+ if (read_write == I2C_SMBUS_READ) {
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+ msg[1].flags |= I2C_M_RECV_LEN;
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+ msg[1].len = 1; /* block length will be added by
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+ the underlying bus driver */
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+ } else {
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+ msg[0].len = data->block[0] + 2;
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+ if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
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+ dev_err(&adapter->dev,
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+ "Invalid block write size %d\n",
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+ data->block[0]);
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+ return -EINVAL;
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+ }
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+ for (i = 1; i < msg[0].len; i++)
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+ 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);
|
Wolfram Sang