diff options
Diffstat (limited to 'include/linux/i2c.h')
| -rw-r--r-- | include/linux/i2c.h | 55 |
1 files changed, 49 insertions, 6 deletions
diff --git a/include/linux/i2c.h b/include/linux/i2c.h index f17da50402a4..898033f41d76 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -253,10 +253,10 @@ static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) #if IS_ENABLED(CONFIG_I2C_SLAVE) enum i2c_slave_event { - I2C_SLAVE_REQ_READ_START, - I2C_SLAVE_REQ_READ_END, - I2C_SLAVE_REQ_WRITE_START, - I2C_SLAVE_REQ_WRITE_END, + I2C_SLAVE_READ_REQUESTED, + I2C_SLAVE_WRITE_REQUESTED, + I2C_SLAVE_READ_PROCESSED, + I2C_SLAVE_WRITE_RECEIVED, I2C_SLAVE_STOP, }; @@ -435,8 +435,8 @@ struct i2c_bus_recovery_info { void (*set_scl)(struct i2c_adapter *, int val); int (*get_sda)(struct i2c_adapter *); - void (*prepare_recovery)(struct i2c_bus_recovery_info *bri); - void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri); + void (*prepare_recovery)(struct i2c_adapter *); + void (*unprepare_recovery)(struct i2c_adapter *); /* gpio recovery */ int scl_gpio; @@ -449,6 +449,48 @@ int i2c_recover_bus(struct i2c_adapter *adap); int i2c_generic_gpio_recovery(struct i2c_adapter *adap); int i2c_generic_scl_recovery(struct i2c_adapter *adap); +/** + * struct i2c_adapter_quirks - describe flaws of an i2c adapter + * @flags: see I2C_AQ_* for possible flags and read below + * @max_num_msgs: maximum number of messages per transfer + * @max_write_len: maximum length of a write message + * @max_read_len: maximum length of a read message + * @max_comb_1st_msg_len: maximum length of the first msg in a combined message + * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message + * + * Note about combined messages: Some I2C controllers can only send one message + * per transfer, plus something called combined message or write-then-read. + * This is (usually) a small write message followed by a read message and + * barely enough to access register based devices like EEPROMs. There is a flag + * to support this mode. It implies max_num_msg = 2 and does the length checks + * with max_comb_*_len because combined message mode usually has its own + * limitations. Because of HW implementations, some controllers can actually do + * write-then-anything or other variants. To support that, write-then-read has + * been broken out into smaller bits like write-first and read-second which can + * be combined as needed. + */ + +struct i2c_adapter_quirks { + u64 flags; + int max_num_msgs; + u16 max_write_len; + u16 max_read_len; + u16 max_comb_1st_msg_len; + u16 max_comb_2nd_msg_len; +}; + +/* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */ +#define I2C_AQ_COMB BIT(0) +/* first combined message must be write */ +#define I2C_AQ_COMB_WRITE_FIRST BIT(1) +/* second combined message must be read */ +#define I2C_AQ_COMB_READ_SECOND BIT(2) +/* both combined messages must have the same target address */ +#define I2C_AQ_COMB_SAME_ADDR BIT(3) +/* convenience macro for typical write-then read case */ +#define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \ + I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR) + /* * i2c_adapter is the structure used to identify a physical i2c bus along * with the access algorithms necessary to access it. @@ -474,6 +516,7 @@ struct i2c_adapter { struct list_head userspace_clients; struct i2c_bus_recovery_info *bus_recovery_info; + const struct i2c_adapter_quirks *quirks; }; #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) |