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gpio: chardev: Add function to retrieve sysfs base for a gpiochip

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This allows to full mux structures which still need the sysfs GPIO
numbers. In combination with mraa_find_gpio_line_by_name, this allows
for platform setup that is independent of the gpiochip probing order.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
This commit is contained in:
Jan Kiszka
2021-01-18 07:05:19 +01:00
committed by Tom Ingleby
parent 56a11363de
commit 0c44a7291b
2 changed files with 38 additions and 0 deletions
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1
include/gpio/gpio_chardev.h
View File

@@ -30,6 +30,7 @@ mraa_gpiod_chip_info* mraa_get_chip_info_by_path(const char* path);
mraa_gpiod_chip_info* mraa_get_chip_info_by_name(const char* name);
mraa_gpiod_chip_info* mraa_get_chip_info_by_label(const char* label);
mraa_gpiod_chip_info* mraa_get_chip_info_by_number(unsigned number);
int mraa_get_chip_base_by_number(unsigned number);
mraa_gpiod_line_info* mraa_get_line_info_from_descriptor(int chip_fd, unsigned line_number);
mraa_gpiod_line_info* mraa_get_line_info_by_chip_number(unsigned chip_number, unsigned line_number);

37
src/gpio/gpio_chardev.c
View File

@@ -244,6 +244,43 @@ mraa_get_chip_info_by_number(unsigned number)
return cinfo;
}
int
mraa_get_chip_base_by_number(unsigned number)
{
#if defined(PERIPHERALMAN)
return -1;
#else
char* glob;
char* path;
FILE* fh;
int res;
glob = malloc(PATH_MAX);
if (!glob) {
syslog(LOG_ERR, "[GPIOD_INTERFACE]: malloc() fail");
return -1;
}
snprintf(glob, PATH_MAX, "/sys/bus/gpio/devices/gpiochip%d/../gpio/*/base", number);
path = mraa_file_unglob(glob);
free(glob);
if (!path) {
syslog(LOG_ERR, "[GPIOD_INTERFACE]: invalid chip number");
res = -1;
} else {
fh = fopen(path, "r");
if (!fh || fscanf(fh, "%d", &res) != 1) {
syslog(LOG_ERR, "[GPIOD_INTERFACE]: could not read from %s", path);
res = -1;
}
}
free(path);
return res;
#endif
}
mraa_gpiod_line_info*
mraa_get_line_info_from_descriptor(int chip_fd, unsigned line_number)
{