On 12/8/2017 4:11 AM, Lothar Waßmann wrote: >> While implementing the ACPI piece, I have to convert an unsigned long to >> (const void *) in ACPI code so that the APIs are compatible. >> > Just one more remark: Do you need write access to the data the pointer > returned by device_get_match_data() or of_fwnode_get_match_data() > points to? > If not, the return type of those functions should be 'const void *'. Yes, the only reason driver is trying to obtain this data pointer is to modify members of it. I did a quick test with your suggestion. test.c: In function ‘main’: test.c:15:2: error: assignment of member ‘m’ in read-only object t->m = 3; ^ struct test { int m; }; int main(void) { const void *ptr; unsigned long l =4; const struct test *t; ptr = (const void *)l; t = ptr; t->m = 3; } -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html