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hardware_samsung/liblights/lights_helper.c

160 lines
3.8 KiB

/*
* Copyright (C) 2016 The CyanogenMod Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "SamsungLightsHelper"
/* #define LOG_NDEBUG 0 */
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <cutils/log.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <liblights/samsung_lights_helper.h>
/*
* Reads an Integer from a file.
*
* @param path The absolute path string.
* @return The Integer with decimal base, -1 or -errno on error.
*/
static int read_int(char const *path)
{
int fd, len;
int ret = 0;
const int INT_MAX_STRLEN = 10;
char buffer[INT_MAX_STRLEN+1];
fd = open(path, O_RDONLY);
if (fd < 0) {
ret = -errno;
ALOGE("%s: failed to open %s (%s)", __func__, path, strerror(errno));
goto exit;
}
len = read(fd, buffer, INT_MAX_STRLEN-1);
if (len < 0) {
ret = -errno;
ALOGE("%s: failed to read from %s (%s)", __func__, path, strerror(errno));
goto exit;
}
buffer[len] = '\0';
/* now parse the integer from buffer */
char *endptr = NULL;
ret = (int) strtol(buffer, &endptr, 10);
if (ret == 0 && endptr == NULL) {
ret = -1;
ALOGE("%s: failed to extract number from string %s", __func__, buffer);
goto exit;
}
exit:
if (fd >= 0)
close(fd);
return ret;
}
/*
* Writes an Integer to a file.
*
* @param path The absolute path string.
* @param value The Integer value to be written.
* @return 0 on success, -errno on error.
*/
static int write_int(char const *path, const int value)
{
int fd, len, num_bytes;
int ret = 0;
const int INT_MAX_STRLEN = 10;
char buffer[INT_MAX_STRLEN+1];
fd = open(path, O_WRONLY);
if (fd < 0) {
ret = -errno;
ALOGE("%s: failed to open %s (%s)", __func__, path, strerror(errno));
goto exit;
}
num_bytes = sprintf(buffer, "%d", value);
len = write(fd, buffer, num_bytes);
if (len < 0) {
ret = -errno;
ALOGE("%s: failed to write to %s (%s)", __func__, path, strerror(errno));
goto exit;
}
exit:
if (fd >= 0)
close(fd);
return ret;
}
/*
* Set the current button brightness via sysfs.
*
* @param brightness The brightness value.
* @return 0 on success, errno on error.
*/
inline int set_cur_button_brightness(const int brightness)
{
return write_int(BUTTON_BRIGHTNESS_NODE, brightness);
}
/*
* Read the current panel brightness from sysfs.
*
* @return The brightness as Integer, -1 on error.
*/
inline int get_cur_panel_brightness()
{
return read_int(PANEL_BRIGHTNESS_NODE);
}
/*
* Read the maximum panel brightness from sysfs.
*
* @return The brightness as Integer, -1 on error.
*/
inline int get_max_panel_brightness()
{
return read_int(PANEL_MAX_BRIGHTNESS_NODE);
}
/*
* Set the current panel brightness via sysfs.
*
* @param brightness The (scaled) brightness value.
* @return 0 on success, errno on error.
*/
inline int set_cur_panel_brightness(const int brightness)
{
return write_int(PANEL_BRIGHTNESS_NODE, brightness);
}
/*
* Set the maximum panel brightness via sysfs.
*
* @param brightness The brightness value.
* @return 0 on success, errno on error.
*/
inline int set_max_panel_brightness(const int brightness)
{
return write_int(PANEL_MAX_BRIGHTNESS_NODE, brightness);
}