Commit f53f15ba authored by Liguang Zhang's avatar Liguang Zhang Committed by Wolfram Sang
Browse files

i2c: designware: Get right data length 



IC_DATA_CMD[11] indicates the first data byte received after the address
phase for receive transfer in Master receiver or Slave receiver mode,
this bit was set in some transfer flow. IC_DATA_CMD[7:0] contains the
data to be transmitted or received on the I2C bus, so we should use the
lower 8 bits to get the real data length.

Signed-off-by: default avatarLiguang Zhang <zhangliguang@linux.alibaba.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent a1858ce0

drivers/i2c/busses/i2c-designware-core.h

+2 −0
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ 
#define DW_IC_CON_TX_EMPTY_CTRL			BIT(8)

#define DW_IC_CON_RX_FIFO_FULL_HLD_CTRL		BIT(9)



#define DW_IC_DATA_CMD_DAT			GENMASK(7, 0)



/*

 * Registers offset

 */

drivers/i2c/busses/i2c-designware-master.c

+1 −1
Original line number Diff line number Diff line
@@ -432,7 +432,7 @@ i2c_dw_read(struct dw_i2c_dev *dev) 
			regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);

			/* Ensure length byte is a valid value */

			if (flags & I2C_M_RECV_LEN &&

			    tmp <= I2C_SMBUS_BLOCK_MAX && tmp > 0) {

			    (tmp & DW_IC_DATA_CMD_DAT) <= I2C_SMBUS_BLOCK_MAX && tmp > 0) {

				len = i2c_dw_recv_len(dev, tmp);

			}

			*buf++ = tmp;