diff options
Diffstat (limited to 'src/include/device/i2c.h')
| -rw-r--r-- | src/include/device/i2c.h | 128 |
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 = ® - 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 = ® + 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 = ® - 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 = ® + 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); |