I often find ioremap just use PAGE_SIZE as its size like:

drivers/spi/spi-orion.c:715:        dir_acc->vaddr = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
drivers/gpu/ipu-v3/ipu-dmfc.c:182:  priv->base = devm_ioremap(dev, base, PAGE_SIZE);
drivers/gpu/ipu-v3/ipu-dp.c:338:    priv->base = devm_ioremap(dev, base, PAGE_SIZE);
drivers/gpu/ipu-v3/ipu-vdi.c:222:   vdi->base = devm_ioremap(dev, base, PAGE_SIZE);
drivers/gpu/ipu-v3/ipu-di.c:729:    di->base = devm_ioremap(dev, base, PAGE_SIZE);

Is it because it should map at least PAGE_SIZE even if its total length is smaller than PAGE_SIZE?