On 03/07/2019 14:47, Marc Gonzalez wrote: > Come to think of it, I'm really not a fan of "large" macro functions. > I'll outline a different option in v2. My idea is to use a trivial helper function to assign the 3 struct fields, and then a trivial macro to invoke the helper: static void cmd_setup(struct si2168_cmd *cmd, char *args, int wlen, int rlen) { memcpy(cmd->args, args, wlen); cmd->wlen = wlen; cmd->rlen = rlen; } #define CMD_SETUP(cmd, args, rlen) \ cmd_setup(cmd, args, sizeof(args) - 1, rlen) I think this way addresses all of your comments: - since we're using a real function, the compiler can perform type-checking, and the function's prototype is self-documenting. - no more funky __args and __rlen arguments - no local variables Note however, that drivers/media/tuners/si2157.c uses a different struct (struct si2157_cmd). Therefore, if we wanted to apply the same changes to si2157.c, we would have to define a common struct, and replace all the uses of struct si2157_cmd and struct si2168_cmd. That seemed too invasive to do without the maintainer's approval and guidance. Antti, do you Ack this new approach? It's not clear what HW is supported by drivers/media/dvb-frontends/si21xx.c (that's a very generic name). Regards.