linux

iv/linux

History

Pontus Andersson c6ebcedbab i2c: ismt: Separate I2C block read from SMBus block read

Commit b6c159a9cb69 ("i2c: ismt: Don't duplicate the receive length for
block reads") broke I2C block reads. It aimed to fix normal SMBus block
read, but changed the correct behavior of I2C block read in the process.

According to Documentation/i2c/smbus-protocol, one vital difference
between normal SMBus block read and I2C block read is that there is no
byte count prefixed in the data sent on the wire:

 SMBus Block Read:  i2c_smbus_read_block_data()
 S Addr Wr [A] Comm [A]
            S Addr Rd [A] [Count] A [Data] A [Data] A ... A [Data] NA P

 I2C Block Read:  i2c_smbus_read_i2c_block_data()
 S Addr Wr [A] Comm [A]
            S Addr Rd [A] [Data] A [Data] A ... A [Data] NA P

Therefore the two transaction types need to be processed differently in
the driver by copying of the dma_buffer as done previously for the
I2C_SMBUS_I2C_BLOCK_DATA case.

Fixes: b6c159a9cb69 ("i2c: ismt: Don't duplicate the receive length for block reads")
Signed-off-by: Pontus Andersson <epontan@gmail.com>
Tested-by: Stephen Douthit <stephend@adiengineering.com>
Cc: stable@vger.kernel.org
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

2017-10-13 20:31:03 +02:00

algos

i2c: algo-bit: add support for I2C_M_STOP

2017-06-23 20:45:43 +02:00

busses

i2c: ismt: Separate I2C block read from SMBus block read

2017-10-13 20:31:03 +02:00

muxes

Merge branch 'i2c/for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

2017-09-09 14:18:40 -07:00

i2c-boardinfo.c

i2c: allow attaching IRQ resources to i2c_board_info