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Diffstat (limited to 'src/include/device/i2c.h')
-rw-r--r--src/include/device/i2c.h128
1 files changed, 79 insertions, 49 deletions
diff --git a/src/include/device/i2c.h b/src/include/device/i2c.h
index 6115bd15e8..9939bc60bf 100644
--- a/src/include/device/i2c.h
+++ b/src/include/device/i2c.h
@@ -19,6 +19,41 @@
#include <stdint.h>
#include <stdlib.h>
+/**
+ * struct i2c_msg - an I2C transaction segment beginning with START
+ * @addr: Slave address, either seven or ten bits. When this is a ten
+ * bit address, I2C_M_TEN must be set in @flags.
+ * @flags: I2C_M_RD is handled by all adapters.
+ * @len: Number of data bytes in @buf being read from or written to the
+ * I2C slave address. For read transactions where I2C_M_RECV_LEN
+ * is set, the caller guarantees that this buffer can hold up to
+ * 32 bytes in addition to the initial length byte sent by the
+ * slave (plus, if used, the SMBus PEC).
+ * @buf: The buffer into which data is read, or from which it's written.
+ *
+ * An i2c_msg is the low level representation of one segment of an I2C
+ * transaction. It is visible to drivers in the @i2c_transfer() procedure.
+ *
+ * All I2C adapters implement the standard rules for I2C transactions. Each
+ * transaction begins with a START. That is followed by the slave address,
+ * and a bit encoding read versus write. Then follow all the data bytes,
+ * possibly including a byte with SMBus PEC. The transfer terminates with
+ * a NAK, or when all those bytes have been transferred and ACKed. If this
+ * is the last message in a group, it is followed by a STOP. Otherwise it
+ * is followed by the next @i2c_msg transaction segment, beginning with a
+ * (repeated) START.
+ */
+struct i2c_msg {
+ uint16_t flags;
+#define I2C_M_RD 0x0001 /* read data, from slave to master */
+#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
+#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */
+#define I2C_M_NOSTART 0x4000 /* don't send a repeated START */
+ uint16_t slave; /* slave address */
+ uint16_t len; /* msg length */
+ uint8_t *buf; /* pointer to msg data */
+};
+
enum i2c_speed {
I2C_SPEED_STANDARD = 100000,
I2C_SPEED_FAST = 400000,
@@ -32,15 +67,9 @@ enum i2c_address_mode {
I2C_MODE_10_BIT
};
-struct i2c_seg {
- int read;
- uint8_t chip;
- uint8_t *buf;
- int len;
-};
-int platform_i2c_transfer(unsigned int bus, struct i2c_seg *segments,
- int count);
+int platform_i2c_transfer(unsigned int bus, struct i2c_msg *segments,
+ int count);
#define SOFTWARE_I2C_MAX_BUS 10 /* increase as necessary */
@@ -53,15 +82,16 @@ struct software_i2c_ops {
extern struct software_i2c_ops *software_i2c[];
-int software_i2c_transfer(unsigned int bus, struct i2c_seg *segments,
- int count);
-void software_i2c_wedge_ack(unsigned int bus, u8 chip);
-void software_i2c_wedge_read(unsigned int bus, u8 chip, u8 reg, int bit_count);
-void software_i2c_wedge_write(unsigned int bus, u8 chip, u8 reg, int bit_count);
+int software_i2c_transfer(unsigned int bus, struct i2c_msg *segments,
+ int count);
+void software_i2c_wedge_ack(unsigned int bus, u8 slave);
+void software_i2c_wedge_read(unsigned int bus, u8 slave, u8 reg, int bit_count);
+void software_i2c_wedge_write(unsigned int bus, u8 slave, u8 reg,
+ int bit_count);
-int i2c_read_field(unsigned int bus, uint8_t chip, uint8_t reg, uint8_t *data,
+int i2c_read_field(unsigned int bus, uint8_t slave, uint8_t reg, uint8_t *data,
uint8_t mask, uint8_t shift);
-int i2c_write_field(unsigned int bus, uint8_t chip, uint8_t reg, uint8_t data,
+int i2c_write_field(unsigned int bus, uint8_t slave, uint8_t reg, uint8_t data,
uint8_t mask, uint8_t shift);
/*
@@ -70,7 +100,7 @@ int i2c_write_field(unsigned int bus, uint8_t chip, uint8_t reg, uint8_t data,
* Need this ugly stub to arbitrate since I2C device drivers hardcode
* 'i2c_transfer()' as their entry point.
*/
-static inline int i2c_transfer(unsigned int bus, struct i2c_seg *segments,
+static inline int i2c_transfer(unsigned int bus, struct i2c_msg *segments,
int count)
{
if (CONFIG_SOFTWARE_I2C)
@@ -85,11 +115,11 @@ static inline int i2c_transfer(unsigned int bus, struct i2c_seg *segments,
*
* [start][slave addr][r][data][stop]
*/
-static inline int i2c_read_raw(unsigned int bus, uint8_t chip, uint8_t *data,
+static inline int i2c_read_raw(unsigned int bus, uint8_t slave, uint8_t *data,
int len)
{
- struct i2c_seg seg = {
- .read = 1, .chip = chip, .buf = data, .len = len
+ struct i2c_msg seg = {
+ .flags = I2C_M_RD, .slave = slave, .buf = data, .len = len
};
return i2c_transfer(bus, &seg, 1);
@@ -100,11 +130,11 @@ static inline int i2c_read_raw(unsigned int bus, uint8_t chip, uint8_t *data,
*
* [start][slave addr][w][data][stop]
*/
-static inline int i2c_write_raw(unsigned int bus, uint8_t chip, uint8_t *data,
+static inline int i2c_write_raw(unsigned int bus, uint8_t slave, uint8_t *data,
int len)
{
- struct i2c_seg seg = {
- .read = 0, .chip = chip, .buf = data, .len = len
+ struct i2c_msg seg = {
+ .flags = 0, .slave = slave, .buf = data, .len = len
};
return i2c_transfer(bus, &seg, 1);
@@ -115,19 +145,19 @@ static inline int i2c_write_raw(unsigned int bus, uint8_t chip, uint8_t *data,
*
* [start][slave addr][w][register addr][start][slave addr][r][data...][stop]
*/
-static inline int i2c_read_bytes(unsigned int bus, uint8_t chip, uint8_t reg,
+static inline int i2c_read_bytes(unsigned int bus, uint8_t slave, uint8_t reg,
uint8_t *data, int len)
{
- struct i2c_seg seg[2];
+ struct i2c_msg seg[2];
- seg[0].read = 0;
- seg[0].chip = chip;
- seg[0].buf = &reg;
- seg[0].len = 1;
- seg[1].read = 1;
- seg[1].chip = chip;
- seg[1].buf = data;
- seg[1].len = len;
+ seg[0].flags = 0;
+ seg[0].slave = slave;
+ seg[0].buf = &reg;
+ seg[0].len = 1;
+ seg[1].flags = I2C_M_RD;
+ seg[1].slave = slave;
+ seg[1].buf = data;
+ seg[1].len = len;
return i2c_transfer(bus, seg, ARRAY_SIZE(seg));
}
@@ -137,19 +167,19 @@ static inline int i2c_read_bytes(unsigned int bus, uint8_t chip, uint8_t reg,
*
* [start][slave addr][w][register addr][start][slave addr][r][data][stop]
*/
-static inline int i2c_readb(unsigned int bus, uint8_t chip, uint8_t reg,
+static inline int i2c_readb(unsigned int bus, uint8_t slave, uint8_t reg,
uint8_t *data)
{
- struct i2c_seg seg[2];
+ struct i2c_msg seg[2];
- seg[0].read = 0;
- seg[0].chip = chip;
- seg[0].buf = &reg;
- seg[0].len = 1;
- seg[1].read = 1;
- seg[1].chip = chip;
- seg[1].buf = data;
- seg[1].len = 1;
+ seg[0].flags = 0;
+ seg[0].slave = slave;
+ seg[0].buf = &reg;
+ seg[0].len = 1;
+ seg[1].flags = I2C_M_RD;
+ seg[1].slave = slave;
+ seg[1].buf = data;
+ seg[1].len = 1;
return i2c_transfer(bus, seg, ARRAY_SIZE(seg));
}
@@ -159,16 +189,16 @@ static inline int i2c_readb(unsigned int bus, uint8_t chip, uint8_t reg,
*
* [start][slave addr][w][register addr][data][stop]
*/
-static inline int i2c_writeb(unsigned int bus, uint8_t chip, uint8_t reg,
+static inline int i2c_writeb(unsigned int bus, uint8_t slave, uint8_t reg,
uint8_t data)
{
- struct i2c_seg seg;
+ struct i2c_msg seg;
uint8_t buf[] = {reg, data};
- seg.read = 0;
- seg.chip = chip;
- seg.buf = buf;
- seg.len = ARRAY_SIZE(buf);
+ seg.flags = 0;
+ seg.slave = slave;
+ seg.buf = buf;
+ seg.len = ARRAY_SIZE(buf);
return i2c_transfer(bus, &seg, 1);
}
@@ -188,7 +218,7 @@ struct i2c_bus_operations {
int i2c_dev_find_bus(struct device *dev);
/* Variants of I2C helper functions that take a device instead of bus number */
-int i2c_dev_transfer(struct device *dev, struct i2c_seg *segments, int count);
+int i2c_dev_transfer(struct device *dev, struct i2c_msg *segments, int count);
int i2c_dev_readb(struct device *dev, uint8_t reg, uint8_t *data);
int i2c_dev_writeb(struct device *dev, uint8_t reg, uint8_t data);
int i2c_dev_read_bytes(struct device *dev, uint8_t reg, uint8_t *data, int len);