Home | History | Annotate | Download | only in vibrator 
      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <hardware/vibrator.h>
     18 #include <hardware/hardware.h>
     19 
     20 #include <cutils/log.h>
     21 
     22 #include <malloc.h>
     23 #include <stdio.h>
     24 #include <unistd.h>
     25 #include <fcntl.h>
     26 #include <errno.h>
     27 #include <math.h>
     28 
     29 static const char THE_DEVICE[] = "/sys/class/timed_output/vibrator/enable";
     30 
     31 static int vibra_exists() {
     32     int fd;
     33 
     34     fd = TEMP_FAILURE_RETRY(open(THE_DEVICE, O_RDWR));
     35     if(fd < 0) {
     36         ALOGE("Vibrator file does not exist : %d", fd);
     37         return 0;
     38     }
     39 
     40     close(fd);
     41     return 1;
     42 }
     43 
     44 static int sendit(unsigned int timeout_ms)
     45 {
     46     int to_write, written, ret, fd;
     47 
     48     char value[20]; /* large enough for millions of years */
     49 
     50     fd = TEMP_FAILURE_RETRY(open(THE_DEVICE, O_RDWR));
     51     if(fd < 0) {
     52         return -errno;
     53     }
     54 
     55     to_write = snprintf(value, sizeof(value), "%u\n", timeout_ms);
     56     written = TEMP_FAILURE_RETRY(write(fd, value, to_write));
     57 
     58     if (written == -1) {
     59         ret = -errno;
     60     } else if (written != to_write) {
     61         /* even though EAGAIN is an errno value that could be set
     62            by write() in some cases, none of them apply here.  So, this return
     63            value can be clearly identified when debugging and suggests the
     64            caller that it may try to call vibraror_on() again */
     65         ret = -EAGAIN;
     66     } else {
     67         ret = 0;
     68     }
     69 
     70     errno = 0;
     71     close(fd);
     72 
     73     return ret;
     74 }
     75 
     76 static int vibra_on(vibrator_device_t* vibradev __unused, unsigned int timeout_ms)
     77 {
     78     /* constant on, up to maximum allowed time */
     79     return sendit(timeout_ms);
     80 }
     81 
     82 static int vibra_off(vibrator_device_t* vibradev __unused)
     83 {
     84     return sendit(0);
     85 }
     86 
     87 static int vibra_close(hw_device_t *device)
     88 {
     89     free(device);
     90     return 0;
     91 }
     92 
     93 static int vibra_open(const hw_module_t* module, const char* id __unused,
     94                       hw_device_t** device __unused) {
     95     if (!vibra_exists()) {
     96         ALOGE("Vibrator device does not exist. Cannot start vibrator");
     97         return -ENODEV;
     98     }
     99 
    100     vibrator_device_t *vibradev = calloc(1, sizeof(vibrator_device_t));
    101 
    102     if (!vibradev) {
    103         ALOGE("Can not allocate memory for the vibrator device");
    104         return -ENOMEM;
    105     }
    106 
    107     vibradev->common.tag = HARDWARE_DEVICE_TAG;
    108     vibradev->common.module = (hw_module_t *) module;
    109     vibradev->common.version = HARDWARE_DEVICE_API_VERSION(1,0);
    110     vibradev->common.close = vibra_close;
    111 
    112     vibradev->vibrator_on = vibra_on;
    113     vibradev->vibrator_off = vibra_off;
    114 
    115     *device = (hw_device_t *) vibradev;
    116 
    117     return 0;
    118 }
    119 
    120 /*===========================================================================*/
    121 /* Default vibrator HW module interface definition                           */
    122 /*===========================================================================*/
    123 
    124 static struct hw_module_methods_t vibrator_module_methods = {
    125     .open = vibra_open,
    126 };
    127 
    128 struct hw_module_t HAL_MODULE_INFO_SYM = {
    129     .tag = HARDWARE_MODULE_TAG,
    130     .module_api_version = VIBRATOR_API_VERSION,
    131     .hal_api_version = HARDWARE_HAL_API_VERSION,
    132     .id = VIBRATOR_HARDWARE_MODULE_ID,
    133     .name = "Default vibrator HAL",
    134     .author = "The Android Open Source Project",
    135     .methods = &vibrator_module_methods,
    136 };
    137