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Diffstat (limited to 'include/i2c.h')
| -rw-r--r-- | include/i2c.h | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/include/i2c.h b/include/i2c.h index 1b4078e..9c6a60c 100644 --- a/include/i2c.h +++ b/include/i2c.h @@ -18,6 +18,355 @@ #define _I2C_H_ /* + * For now there are essentially two parts to this file - driver model + * here at the top, and the older code below (with CONFIG_SYS_I2C being + * most recent). The plan is to migrate everything to driver model. + * The driver model structures and API are separate as they are different + * enough as to be incompatible for compilation purposes. + */ + +#ifdef CONFIG_DM_I2C + +enum dm_i2c_chip_flags { + DM_I2C_CHIP_10BIT = 1 << 0, /* Use 10-bit addressing */ + DM_I2C_CHIP_RD_ADDRESS = 1 << 1, /* Send address for each read byte */ + DM_I2C_CHIP_WR_ADDRESS = 1 << 2, /* Send address for each write byte */ +}; + +/** + * struct dm_i2c_chip - information about an i2c chip + * + * An I2C chip is a device on the I2C bus. It sits at a particular address + * and normally supports 7-bit or 10-bit addressing. + * + * To obtain this structure, use dev_get_parentdata(dev) where dev is the + * chip to examine. + * + * @chip_addr: Chip address on bus + * @offset_len: Length of offset in bytes. A single byte offset can + * represent up to 256 bytes. A value larger than 1 may be + * needed for larger devices. + * @flags: Flags for this chip (dm_i2c_chip_flags) + * @emul: Emulator for this chip address (only used for emulation) + */ +struct dm_i2c_chip { + uint chip_addr; + uint offset_len; + uint flags; +#ifdef CONFIG_SANDBOX + struct udevice *emul; +#endif +}; + +/** + * struct dm_i2c_bus- information about an i2c bus + * + * An I2C bus contains 0 or more chips on it, each at its own address. The + * bus can operate at different speeds (measured in Hz, typically 100KHz + * or 400KHz). + * + * To obtain this structure, use bus->uclass_priv where bus is the I2C + * bus udevice. + * + * @speed_hz: Bus speed in hertz (typically 100000) + */ +struct dm_i2c_bus { + int speed_hz; +}; + +/** + * i2c_read() - read bytes from an I2C chip + * + * To obtain an I2C device (called a 'chip') given the I2C bus address you + * can use i2c_get_chip(). To obtain a bus by bus number use + * uclass_get_device_by_seq(UCLASS_I2C, <bus number>). + * + * To set the address length of a devce use i2c_set_addr_len(). It + * defaults to 1. + * + * @dev: Chip to read from + * @offset: Offset within chip to start reading + * @buffer: Place to put data + * @len: Number of bytes to read + * + * @return 0 on success, -ve on failure + */ +int i2c_read(struct udevice *dev, uint offset, uint8_t *buffer, + int len); + +/** + * i2c_write() - write bytes to an I2C chip + * + * See notes for i2c_read() above. + * + * @dev: Chip to write to + * @offset: Offset within chip to start writing + * @buffer: Buffer containing data to write + * @len: Number of bytes to write + * + * @return 0 on success, -ve on failure + */ +int i2c_write(struct udevice *dev, uint offset, const uint8_t *buffer, + int len); + +/** + * i2c_probe() - probe a particular chip address + * + * This can be useful to check for the existence of a chip on the bus. + * It is typically implemented by writing the chip address to the bus + * and checking that the chip replies with an ACK. + * + * @bus: Bus to probe + * @chip_addr: 7-bit address to probe (10-bit and others are not supported) + * @chip_flags: Flags for the probe (see enum dm_i2c_chip_flags) + * @devp: Returns the device found, or NULL if none + * @return 0 if a chip was found at that address, -ve if not + */ +int i2c_probe(struct udevice *bus, uint chip_addr, uint chip_flags, + struct udevice **devp); + +/** + * i2c_set_bus_speed() - set the speed of a bus + * + * @bus: Bus to adjust + * @speed: Requested speed in Hz + * @return 0 if OK, -EINVAL for invalid values + */ +int i2c_set_bus_speed(struct udevice *bus, unsigned int speed); + +/** + * i2c_get_bus_speed() - get the speed of a bus + * + * @bus: Bus to check + * @return speed of selected I2C bus in Hz, -ve on error + */ +int i2c_get_bus_speed(struct udevice *bus); + +/** + * i2c_set_chip_flags() - set flags for a chip + * + * Typically addresses are 7 bits, but for 10-bit addresses you should set + * flags to DM_I2C_CHIP_10BIT. All accesses will then use 10-bit addressing. + * + * @dev: Chip to adjust + * @flags: New flags + * @return 0 if OK, -EINVAL if value is unsupported, other -ve value on error + */ +int i2c_set_chip_flags(struct udevice *dev, uint flags); + +/** + * i2c_get_chip_flags() - get flags for a chip + * + * @dev: Chip to check + * @flagsp: Place to put flags + * @return 0 if OK, other -ve value on error + */ +int i2c_get_chip_flags(struct udevice *dev, uint *flagsp); + +/** + * i2c_set_offset_len() - set the offset length for a chip + * + * The offset used to access a chip may be up to 4 bytes long. Typically it + * is only 1 byte, which is enough for chips with 256 bytes of memory or + * registers. The default value is 1, but you can call this function to + * change it. + * + * @offset_len: New offset length value (typically 1 or 2) + */ + +int i2c_set_chip_offset_len(struct udevice *dev, uint offset_len); +/** + * i2c_deblock() - recover a bus that is in an unknown state + * + * See the deblock() method in 'struct dm_i2c_ops' for full information + * + * @bus: Bus to recover + * @return 0 if OK, -ve on error + */ +int i2c_deblock(struct udevice *bus); + +/* + * Not all of these flags are implemented in the U-Boot API + */ +enum dm_i2c_msg_flags { + I2C_M_TEN = 0x0010, /* ten-bit chip address */ + I2C_M_RD = 0x0001, /* read data, from slave to master */ + I2C_M_STOP = 0x8000, /* send stop after this message */ + I2C_M_NOSTART = 0x4000, /* no start before this message */ + I2C_M_REV_DIR_ADDR = 0x2000, /* invert polarity of R/W bit */ + I2C_M_IGNORE_NAK = 0x1000, /* continue after NAK */ + I2C_M_NO_RD_ACK = 0x0800, /* skip the Ack bit on reads */ + I2C_M_RECV_LEN = 0x0400, /* length is first received byte */ +}; + +/** + * struct i2c_msg - an I2C message + * + * @addr: Slave address + * @flags: Flags (see enum dm_i2c_msg_flags) + * @len: Length of buffer in bytes, may be 0 for a probe + * @buf: Buffer to send/receive, or NULL if no data + */ +struct i2c_msg { + uint addr; + uint flags; + uint len; + u8 *buf; +}; + +/** + * struct i2c_msg_list - a list of I2C messages + * + * This is called i2c_rdwr_ioctl_data in Linux but the name does not seem + * appropriate in U-Boot. + * + * @msg: Pointer to i2c_msg array + * @nmsgs: Number of elements in the array + */ +struct i2c_msg_list { + struct i2c_msg *msgs; + uint nmsgs; +}; + +/** + * struct dm_i2c_ops - driver operations for I2C uclass + * + * Drivers should support these operations unless otherwise noted. These + * operations are intended to be used by uclass code, not directly from + * other code. + */ +struct dm_i2c_ops { + /** + * xfer() - transfer a list of I2C messages + * + * @bus: Bus to read from + * @msg: List of messages to transfer + * @nmsgs: Number of messages in the list + * @return 0 if OK, -EREMOTEIO if the slave did not ACK a byte, + * -ECOMM if the speed cannot be supported, -EPROTO if the chip + * flags cannot be supported, other -ve value on some other error + */ + int (*xfer)(struct udevice *bus, struct i2c_msg *msg, int nmsgs); + + /** + * probe_chip() - probe for the presense of a chip address + * + * This function is optional. If omitted, the uclass will send a zero + * length message instead. + * + * @bus: Bus to probe + * @chip_addr: Chip address to probe + * @chip_flags: Probe flags (enum dm_i2c_chip_flags) + * @return 0 if chip was found, -EREMOTEIO if not, -ENOSYS to fall back + * to default probem other -ve value on error + */ + int (*probe_chip)(struct udevice *bus, uint chip_addr, uint chip_flags); + + /** + * set_bus_speed() - set the speed of a bus (optional) + * + * The bus speed value will be updated by the uclass if this function + * does not return an error. This method is optional - if it is not + * provided then the driver can read the speed from + * bus->uclass_priv->speed_hz + * + * @bus: Bus to adjust + * @speed: Requested speed in Hz + * @return 0 if OK, -EINVAL for invalid values + */ + int (*set_bus_speed)(struct udevice *bus, unsigned int speed); + + /** + * get_bus_speed() - get the speed of a bus (optional) + * + * Normally this can be provided by the uclass, but if you want your + * driver to check the bus speed by looking at the hardware, you can + * implement that here. This method is optional. This method would + * normally be expected to return bus->uclass_priv->speed_hz. + * + * @bus: Bus to check + * @return speed of selected I2C bus in Hz, -ve on error + */ + int (*get_bus_speed)(struct udevice *bus); + + /** + * set_flags() - set the flags for a chip (optional) + * + * This is generally implemented by the uclass, but drivers can + * check the value to ensure that unsupported options are not used. + * This method is optional. If provided, this method will always be + * called when the flags change. + * + * @dev: Chip to adjust + * @flags: New flags value + * @return 0 if OK, -EINVAL if value is unsupported + */ + int (*set_flags)(struct udevice *dev, uint flags); + + /** + * deblock() - recover a bus that is in an unknown state + * + * I2C is a synchronous protocol and resets of the processor in the + * middle of an access can block the I2C Bus until a powerdown of + * the full unit is done. This is because slaves can be stuck + * waiting for addition bus transitions for a transaction that will + * never complete. Resetting the I2C master does not help. The only + * way is to force the bus through a series of transitions to make + * sure that all slaves are done with the transaction. This method + * performs this 'deblocking' if support by the driver. + * + * This method is optional. + */ + int (*deblock)(struct udevice *bus); +}; + +#define i2c_get_ops(dev) ((struct dm_i2c_ops *)(dev)->driver->ops) + +/** + * i2c_get_chip() - get a device to use to access a chip on a bus + * + * This returns the device for the given chip address. The device can then + * be used with calls to i2c_read(), i2c_write(), i2c_probe(), etc. + * + * @bus: Bus to examine + * @chip_addr: Chip address for the new device + * @devp: Returns pointer to new device if found or -ENODEV if not + * found + */ +int i2c_get_chip(struct udevice *bus, uint chip_addr, struct udevice **devp); + +/** + * i2c_get_chip() - get a device to use to access a chip on a bus number + * + * This returns the device for the given chip address on a particular bus + * number. + * + * @busnum: Bus number to examine + * @chip_addr: Chip address for the new device + * @devp: Returns pointer to new device if found or -ENODEV if not + * found + */ +int i2c_get_chip_for_busnum(int busnum, int chip_addr, struct udevice **devp); + +/** + * i2c_chip_ofdata_to_platdata() - Decode standard I2C platform data + * + * This decodes the chip address from a device tree node and puts it into + * its dm_i2c_chip structure. This should be called in your driver's + * ofdata_to_platdata() method. + * + * @blob: Device tree blob + * @node: Node offset to read from + * @spi: Place to put the decoded information + */ +int i2c_chip_ofdata_to_platdata(const void *blob, int node, + struct dm_i2c_chip *chip); + +#endif + +#ifndef CONFIG_DM_I2C + +/* * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING * * The implementation MUST NOT use static or global variables if the @@ -451,4 +800,7 @@ int i2c_get_bus_num_fdt(int node); * @return 0 if port was reset, -1 if not found */ int i2c_reset_port_fdt(const void *blob, int node); + +#endif /* !CONFIG_DM_I2C */ + #endif /* _I2C_H_ */ |