DLN2_SPI_BUF_SIZE
BUILD_BUG_ON(sizeof(*tx) > DLN2_SPI_BUF_SIZE);
BUILD_BUG_ON(sizeof(*rx) > DLN2_SPI_BUF_SIZE);
BUILD_BUG_ON(sizeof(*tx) > DLN2_SPI_BUF_SIZE ||
sizeof(*rx) > DLN2_SPI_BUF_SIZE);
dln2->buf = devm_kmalloc(&pdev->dev, DLN2_SPI_BUF_SIZE, GFP_KERNEL);