From: Quan Nguyen quan@os.amperecomputing.com
commit 49d4db3953cb9004ff94efc0c176e026c820af5a upstream.
Commit 0daede80f870 ("i2c: designware: Convert driver to using regmap API") changes the logic to validate the whole 32-bit return value of DW_IC_DATA_CMD register instead of 8-bit LSB without reason.
Later, commit f53f15ba5a85 ("i2c: designware: Get right data length"), introduced partial fix but not enough because the "tmp > 0" still test tmp as 32-bit value and is wrong in case the IC_DATA_CMD[11] is set.
Revert the logic to just before commit 0daede80f870 ("i2c: designware: Convert driver to using regmap API").
Fixes: f53f15ba5a85 ("i2c: designware: Get right data length") Fixes: 0daede80f870 ("i2c: designware: Convert driver to using regmap API") Cc: stable@vger.kernel.org Signed-off-by: Tam Nguyen tamnguyenchi@os.amperecomputing.com Signed-off-by: Quan Nguyen quan@os.amperecomputing.com Acked-by: Jarkko Nikula jarkko.nikula@linux.intel.com Link: https://lore.kernel.org/r/20230726080001.337353-2-tamnguyenchi@os.amperecomp... Reviewed-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/i2c/busses/i2c-designware-master.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/i2c/busses/i2c-designware-master.c +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -525,9 +525,10 @@ i2c_dw_read(struct dw_i2c_dev *dev) u32 flags = msgs[dev->msg_read_idx].flags;
regmap_read(dev->map, DW_IC_DATA_CMD, &tmp); + tmp &= DW_IC_DATA_CMD_DAT; /* Ensure length byte is a valid value */ if (flags & I2C_M_RECV_LEN && - (tmp & DW_IC_DATA_CMD_DAT) <= I2C_SMBUS_BLOCK_MAX && tmp > 0) { + tmp <= I2C_SMBUS_BLOCK_MAX && tmp > 0) { len = i2c_dw_recv_len(dev, tmp); } *buf++ = tmp;