[PATCH v2] i2c: designware: Get right data length
From: Liguang Zhang
Date: Thu Feb 25 2021 - 09:27:41 EST
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: Liguang Zhang <zhangliguang@xxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-designware-core.h | 2 ++
drivers/i2c/busses/i2c-designware-master.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 85307cfa7109..5392b82f68a4 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -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
*/
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index d6425ad6e6a3..dd27b9dbe931 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -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;
--
2.19.1.6.gb485710b