[L] Change in flashrom[master]: programmer: Add bitbanging programmer driver for Linux libgpiod

[Steve Markgraf (Code Review)]

Attention is currently required from: Felix Singer, Thomas Heijligen, Angel Pons, Anastasia Klimchuk.

Steve Markgraf has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/71801 )

Change subject: programmer: Add bitbanging programmer driver for Linux libgpiod
......................................................................

Patch Set 2:

(6 comments)

Patchset:

PS1:
> forgot to mark unresolved :\

I've added a man page entry for the new programmer and added myself to MAINTAINERS.

Patchset:

PS2: 
I've added a new version of the patch where I addressed the feedback from the code review.

File include/programmer.h:

https://review.coreboot.org/c/flashrom/+/71801/comment/faed55da_07300219 
PS1, Line 75: extern const struct programmer_entry programmer_linux_gpiod;
> Looks like the list is sorted alphabetically

Done

File linux_gpiod.c:

https://review.coreboot.org/c/flashrom/+/71801/comment/e5083920_3a046e5b 
PS1, Line 97: atoi
> Other places use `strtol()` because it's safer

Done, now also characters that are not numbers are detected and result in an error.

https://review.coreboot.org/c/flashrom/+/71801/comment/a1465380_85a6b761 
PS1, Line 142: 	if (register_spi_bitbang_master(&bitbang_spi_master_gpiod, data))
             : 		return 1; /* shutdown function does the cleanup */
             : 
             : 	return 0;
> How about: […]

Done

https://review.coreboot.org/c/flashrom/+/71801/comment/9559c895_1fef8f27 
PS1, Line 148: 	if (data) {
             : 		if (gpiod_line_bulk_num_lines(&data->bulk) > 0)
             : 			gpiod_line_release_bulk(&data->bulk);
             : 
             : 		free(data);
             : 	}
             : 
             : 	if (chip)
             : 		gpiod_chip_close(chip);
> Registering shutdown function early was in the old times :) During 2020, shutdown functions were mov […]

Yes, good point, I'm now re-using the shutdown function and I've changed the first two callsites to return 1.