DLN2_I2C_MAX_XFER_SIZE
u8 buf[DLN2_I2C_MAX_XFER_SIZE];
.max_read_len = DLN2_I2C_MAX_XFER_SIZE,
.max_write_len = DLN2_I2C_MAX_XFER_SIZE,
#define DLN2_I2C_BUF_SIZE (DLN2_I2C_MAX_XFER_SIZE + 16)
u8 buf[DLN2_I2C_MAX_XFER_SIZE];
len = sizeof(*tx) + data_len - DLN2_I2C_MAX_XFER_SIZE;