nvmem: core: Print error on wrong bits DT property

The algorithms in nvmem core are built with the constraint that
bit_offset < 8. If bit_offset is greater the results are wrong. Print an
error if the devicetree 'bits' property is outside of the valid range
and abort parsing.
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240224114516.86365-12-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/core.c

@@ -807,6 +807,11 @@ static int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_nod
 		if (addr && len == (2 * sizeof(u32))) {
 			info.bit_offset = be32_to_cpup(addr++);
 			info.nbits = be32_to_cpup(addr);
+			if (info.bit_offset >= BITS_PER_BYTE || info.nbits < 1) {
+				dev_err(dev, "nvmem: invalid bits on %pOF\n", child);
+				of_node_put(child);
+				return -EINVAL;
+			}
 		}
 
 		info.np = of_node_get(child);