diff options
Diffstat (limited to 'libbacklight.c')
| -rw-r--r-- | libbacklight.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/libbacklight.c b/libbacklight.c new file mode 100644 index 0000000..2354829 --- /dev/null +++ b/libbacklight.c @@ -0,0 +1,231 @@ +#define _GNU_SOURCE + +#include <libbacklight.h> +#include <stdio.h> +#include <sys/types.h> +#include <dirent.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <malloc.h> +#include <string.h> + +static const char *output_names[] = { "None", + "VGA", + "DVI", + "DVI", + "DVI", + "Composite", + "TV", + "LVDS", + "CTV", + "DIN", + "DP", + "HDMI", + "HDMI", +}; + +static long backlight_get(struct backlight *backlight, char *node) +{ + char buffer[100]; + char *path; + int fd; + long value, ret; + + asprintf(&path, "%s/%s", backlight->path, node); + fd = open(path, O_RDONLY); + if (fd < 0) { + ret = -1; + goto out; + } + + ret = read(fd, &buffer, sizeof(buffer)); + if (ret < 1) { + ret = -1; + goto out; + } + + value = strtol(buffer, NULL, 10); + ret = value; +out: + close(fd); + if (path) + free(path); + return ret; +} + +long backlight_get_brightness(struct backlight *backlight) +{ + return backlight_get(backlight, "brightness"); +} + +long backlight_get_max_brightness(struct backlight *backlight) +{ + return backlight_get(backlight, "max_brightness"); +} + +long backlight_get_actual_brightness(struct backlight *backlight) +{ + return backlight_get(backlight, "actual_brightness"); +} + +long backlight_set_brightness(struct backlight *backlight, long brightness) +{ + char *path; + char *buffer = NULL; + int fd; + long value, ret; + + asprintf(&path, "%s/%s", backlight->path, "brightness"); + fd = open(path, O_RDWR); + if (fd < 0) { + ret = -1; + goto out; + } + + ret = read(fd, &buffer, sizeof(buffer)); + if (ret < 1) { + ret = -1; + goto out; + } + + asprintf(&buffer, "%ld", brightness); + ret = write(fd, buffer, strlen(buffer)); + if (ret < 0) { + ret = -1; + goto out; + } + + ret = backlight_get_brightness(backlight); +out: + if (buffer) + free(buffer); + if (path) + free(path); + close(fd); + return ret; +} + +struct backlight *backlight_init(struct pci_device *dev, int card, + int connector_type, int connector_type_id) +{ + char *pci_name; + char *drm_name; + char *chosen_path = NULL; + DIR *backlights; + struct dirent *entry; + enum backlight_type type = 0; + char buffer[100]; + struct backlight *backlight; + + asprintf(&pci_name, "%04x:%02x:%02x.%d", dev->domain, dev->bus, + dev->dev, dev->func); + asprintf(&drm_name, "card%d-%s-%d", card, output_names[connector_type], + connector_type_id); + + backlights = opendir("/sys/class/backlight"); + + if (!backlights) + return NULL; + + while ((entry = readdir(backlights))) { + char *backlight_path; + char *parent; + char *path; + enum backlight_type entry_type; + int fd, ret; + + if (entry->d_name[0] == '.') + continue; + + asprintf(&backlight_path, "%s/%s", "/sys/class/backlight", + entry->d_name); + asprintf(&path, "%s/%s", backlight_path, "type"); + fd = open(path, O_RDONLY); + + if (fd < 0) + goto out; + + ret = read (fd, &buffer, sizeof(buffer)); + close (fd); + + if (ret < 1) + goto out; + + buffer[ret] = '\0'; + + if (!strncmp(buffer, "raw\n", sizeof(buffer))) + entry_type = BACKLIGHT_RAW; + else if (!strncmp(buffer, "platform\n", sizeof(buffer))) + entry_type = BACKLIGHT_PLATFORM; + else if (!strncmp(buffer, "firmware\n", sizeof(buffer))) + entry_type = BACKLIGHT_FIRMWARE; + else + goto out; + + free (path); + asprintf(&path, "%s/%s", backlight_path, "device"); + ret = readlink(path, buffer, sizeof(buffer)); + + if (ret < 0) + goto out; + + parent = basename(buffer); + + if (entry_type == BACKLIGHT_RAW) { + if (strcmp(drm_name, parent) && + strcmp(pci_name, parent)) { + goto out; + } + } + + if (entry_type == BACKLIGHT_FIRMWARE) { + /* Older kernels won't provide a valid path here... */ + unsigned int domain, bus, device, function; + ret = sscanf(parent, "%04x:%02x:%02x.%u", &domain, &bus, + &device, &function); + if (ret == 4) { + if (strcmp(pci_name, parent)) + goto out; + } + } + + if (entry_type < type) + goto out; + + type = entry_type; + + if (chosen_path) + free(chosen_path); + chosen_path = strdup(backlight_path); + + out: + free(backlight_path); + free(path); + } + + if (!chosen_path) + return NULL; + + backlight = malloc(sizeof(struct backlight)); + + if (!backlight) + goto err; + + backlight->path = chosen_path; + backlight->type = type; + + backlight->max_brightness = backlight_get_max_brightness(backlight); + if (backlight->max_brightness < 0) + goto err; + + backlight->brightness = backlight_get_actual_brightness(backlight); + if (backlight->brightness < 0) + goto err; + + return backlight; +err: + if (chosen_path) + free(chosen_path); + free (backlight); + return NULL; +} |