xref: /linux/Documentation/i2c/busses/i2c-mlxcpld.rst (revision 976e3645923bdd2fe7893aae33fd7a21098bfb28)
1==================
2Driver i2c-mlxcpld
3==================
4
5Author: Michael Shych <michaelsh@mellanox.com>
6
7This is the Mellanox I2C controller logic, implemented in Lattice CPLD
8device.
9
10Device supports:
11 - Master mode.
12 - One physical bus.
13 - Polling mode.
14
15This controller is equipped within the next Mellanox systems:
16"msx6710", "msx6720", "msb7700", "msn2700", "msx1410", "msn2410", "msb7800",
17"msn2740", "msn2100".
18
19The next transaction types are supported:
20 - Receive Byte/Block.
21 - Send Byte/Block.
22 - Read Byte/Block.
23 - Write Byte/Block.
24
25Registers:
26
27=============== === =======================================================================
28CPBLTY		0x0 - capability reg.
29			Bits [6:5] - transaction length. b01 - 72B is supported,
30			36B in other case.
31			Bit 7 - SMBus block read support.
32CTRL		0x1 - control reg.
33			Resets all the registers.
34HALF_CYC	0x4 - cycle reg.
35			Configure the width of I2C SCL half clock cycle (in 4 LPC_CLK
36			units).
37I2C_HOLD	0x5 - hold reg.
38			OE (output enable) is delayed by value set to this register
39			(in LPC_CLK units)
40CMD			0x6 - command reg.
41			Bit 0, 0 = write, 1 = read.
42			Bits [7:1] - the 7bit Address of the I2C device.
43			It should be written last as it triggers an I2C transaction.
44NUM_DATA	0x7 - data size reg.
45			Number of data bytes to write in read transaction
46NUM_ADDR	0x8 - address reg.
47			Number of address bytes to write in read transaction.
48STATUS		0x9 - status reg.
49			Bit 0 - transaction is completed.
50			Bit 4 - ACK/NACK.
51DATAx		0xa - 0x54  - 68 bytes data buffer regs.
52			For write transaction address is specified in four first bytes
53			(DATA1 - DATA4), data starting from DATA4.
54			For read transactions address is sent in a separate transaction and
55			specified in the four first bytes (DATA0 - DATA3). Data is read
56			starting from DATA0.
57=============== === =======================================================================
58