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gpio: chardev: Add helper to retrieve gpiochip and line offset by line name

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This makes the retrieval robust against chips being reordered during
boot. The results can be used to fill out mraa_pin_t while initializing
a board.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
This commit is contained in:
Jan Kiszka
2021-01-18 07:11:20 +01:00
committed by Tom Ingleby
parent fdab66958e
commit 56a11363de
2 changed files with 46 additions and 0 deletions
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44
src/gpio/gpio_chardev.c
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@@ -444,3 +444,47 @@ mraa_get_chip_infos(mraa_gpiod_chip_info*** cinfos)
return num_chips;
}
#ifndef GPIO_MAX_NAME_SIZE
#define GPIO_MAX_NAME_SIZE 32
#endif
int
mraa_find_gpio_line_by_name(const char *name, unsigned *chip_number, unsigned *line_number)
{
mraa_gpiod_chip_info **cinfos;
mraa_gpiod_chip_info *cinfo;
mraa_gpiod_line_info *linfo;
int num_chips, i;
num_chips = mraa_get_chip_infos(&cinfos);
if (num_chips < 0) {
return -1;
}
for_each_gpio_chip(cinfo, cinfos, num_chips) {
for (i = 0; i < cinfo->chip_info.lines; i++) {
linfo = mraa_get_line_info_by_chip_name(cinfo->chip_info.name, i);
if (!strncmp(linfo->name, name, GPIO_MAX_NAME_SIZE)) {
if (chip_number) {
/* idx is coming from `for_each_gpio_chip` definition */
*chip_number = idx;
}
if (line_number) {
*line_number = linfo->line_offset;
}
free(linfo);
free(cinfos);
return 0;
}
free(linfo);
}
}
free(cinfos);
return -1;
}