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      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 <stdio.h>
     23 #include <unistd.h>
     24 #include <fcntl.h>
     25 #include <errno.h>
     26 #include <math.h>
     27 
     28 static const char THE_DEVICE[] = "/sys/class/timed_output/vibrator/enable";
     29 
     30 static int vibra_exists() {
     31     int fd;
     32 
     33     fd = TEMP_FAILURE_RETRY(open(THE_DEVICE, O_RDWR));
     34     if(fd < 0) {
     35         ALOGE("Vibrator file does not exist : %d", fd);
     36         return 0;
     37     }
     38 
     39     close(fd);
     40     return 1;
     41 }
     42 
     43 static int sendit(unsigned int timeout_ms)
     44 {
     45     int to_write, written, ret, fd;
     46 
     47     char value[20]; /* large enough for millions of years */
     48 
     49     fd = TEMP_FAILURE_RETRY(open(THE_DEVICE, O_RDWR));
     50     if(fd < 0) {
     51         return -errno;
     52     }
     53 
     54     to_write = snprintf(value, sizeof(value), "%u\n", timeout_ms);
     55     written = TEMP_FAILURE_RETRY(write(fd, value, to_write));
     56 
     57     if (written == -1) {
     58         ret = -errno;
     59     } else if (written != to_write) {
     60         /* even though EAGAIN is an errno value that could be set
     61            by write() in some cases, none of them apply here.  So, this return
     62            value can be clearly identified when debugging and suggests the
     63            caller that it may try to call vibraror_on() again */
     64         ret = -EAGAIN;
     65     } else {
     66         ret = 0;
     67     }
     68 
     69     errno = 0;
     70     close(fd);
     71 
     72     return ret;
     73 }
     74 
     75 static int vibra_on(vibrator_device_t* vibradev __unused, unsigned int timeout_ms)
     76 {
     77     /* constant on, up to maximum allowed time */
     78     return sendit(timeout_ms);
     79 }
     80 
     81 static int vibra_off(vibrator_device_t* vibradev __unused)
     82 {
     83     return sendit(0);
     84 }
     85 
     86 static int vibra_close(hw_device_t *device)
     87 {
     88     free(device);
     89     return 0;
     90 }
     91 
     92 static int vibra_open(const hw_module_t* module, const char* id __unused,
     93                       hw_device_t** device __unused) {
     94     if (!vibra_exists()) {
     95         ALOGE("Vibrator device does not exist. Cannot start vibrator");
     96         return -ENODEV;
     97     }
     98 
     99     vibrator_device_t *vibradev = calloc(1, sizeof(vibrator_device_t));
    100 
    101     if (!vibradev) {
    102         ALOGE("Can not allocate memory for the vibrator device");
    103         return -ENOMEM;
    104     }
    105 
    106     vibradev->common.tag = HARDWARE_DEVICE_TAG;
    107     vibradev->common.module = (hw_module_t *) module;
    108     vibradev->common.version = HARDWARE_DEVICE_API_VERSION(1,0);
    109     vibradev->common.close = vibra_close;
    110 
    111     vibradev->vibrator_on = vibra_on;
    112     vibradev->vibrator_off = vibra_off;
    113 
    114     *device = (hw_device_t *) vibradev;
    115 
    116     return 0;
    117 }
    118 
    119 /*===========================================================================*/
    120 /* Default vibrator HW module interface definition                           */
    121 /*===========================================================================*/
    122 
    123 static struct hw_module_methods_t vibrator_module_methods = {
    124     .open = vibra_open,
    125 };
    126 
    127 struct hw_module_t HAL_MODULE_INFO_SYM = {
    128     .tag = HARDWARE_MODULE_TAG,
    129     .module_api_version = VIBRATOR_API_VERSION,
    130     .hal_api_version = HARDWARE_HAL_API_VERSION,
    131     .id = VIBRATOR_HARDWARE_MODULE_ID,
    132     .name = "Default vibrator HAL",
    133     .author = "The Android Open Source Project",
    134     .methods = &vibrator_module_methods,
    135 };
    136