STPK-1429 Groundwork for per sensor sampling rate

This supports sampling rate as used by the Intel Sensor Hub.
That conveniently performs the syfs read and double enable
buffer operation that the ISH sensor seem to require.

Issue: STPK-1429

Change-Id: I6e5b6419bb3dc83563849a8d65d7688b6b264bf6
Signed-off-by: Patrick Porlan <patrick.porlan@intel.com>

diff --git a/common.h b/common.h
index 3d4b855..5b3a6f7 100644 (file)
--- a/common.h
+++ b/common.h
@@ -19,6 +19,7 @@
 #define TRIGGER_PATH           BASE_PATH "trigger/current_trigger"
 #define COMMON_OFFSET_PATH     BASE_PATH "in_%s_offset"
 #define COMMON_SCALE_PATH      BASE_PATH "in_%s_scale"
+#define COMMON_SAMPLING_PATH   BASE_PATH "in_%s_sampling_frequency"
 
 #define MAX_TYPE_SPEC_LEN 32   /* Channel type spec len; ex: "le:u10/16>>0" */
 #define MAX_SENSOR_REPORT_SIZE 32      /* Sensor report buffer size */
@@ -77,6 +78,8 @@ struct sensor_info_t
        float offset;   /* (cooked = raw + offset) * scale */
        float scale;
 
+       int sampling_rate;      /* requested events / second */
+
        int dev_num;    /* Associated iio dev num, ex: 3 for /dev/iio:device3 */
        int enable_count;
 

diff --git a/control.c b/control.c
index f6f44df..7cf1efd 100644 (file)
--- a/control.c
+++ b/control.c
@@ -591,6 +591,7 @@ return_first_available_sensor_report:
                        ALOGV("Report on sensor %d\n", s);
                        return 1;
                }
+await_event:
 
        /* Keep a minimum time interval between poll operations */
        delta = (get_timestamp() - last_poll_exit_ts)/1000;
@@ -604,6 +605,11 @@ return_first_available_sensor_report:
 
        last_poll_exit_ts = get_timestamp();
 
+       if (nfds == -1) {
+               ALOGI("epoll_wait returned -1 (%s)\n", strerror(errno));
+               goto await_event;
+       }
+
        ALOGV("%d fds signalled\n", nfds);
 
        /* For each of the devices for which a report is available */
@@ -623,13 +629,37 @@ return_first_available_sensor_report:
 }
 
 
-int sensor_set_delay(int handle, int64_t ns)
+int sensor_set_delay(int s, int64_t ns)
 {
        /* Set the rate at which a specific sensor should report events */
-       /* Continuous reports: accelerometer, gyroscope */
-       /* On change with minimum delay between events: ALS, proximity */
-       /* See sensors.h for indication on sensor trigger modes */
-       return -1;
+
+       /* See Android sensors.h for indication on sensor trigger modes */
+
+       char sysfs_path[PATH_MAX];
+       int dev_num             =       sensor_info[s].dev_num;
+       int i                   =       sensor_info[s].catalog_index;
+       const char *prefix      =       sensor_catalog[i].tag;
+       int new_sampling_rate   =       (int) (1000000000L/ns);
+       int cur_sampling_rate;
+
+       ALOGI("sensor_set_delay: sampling rate set to %d\n", new_sampling_rate);
+
+       sprintf(sysfs_path, COMMON_SAMPLING_PATH, dev_num, prefix);
+
+       if (sysfs_read_int(sysfs_path, &cur_sampling_rate) != -1)
+               if (new_sampling_rate != cur_sampling_rate) {
+
+                       if (trig_sensors_per_dev[dev_num])
+                               enable_buffer(dev_num, 0);
+
+                       sysfs_write_int(sysfs_path, new_sampling_rate);
+
+                       if (trig_sensors_per_dev[dev_num])
+                               enable_buffer(dev_num, 1);
+       }
+
+       sensor_info[s].sampling_rate = new_sampling_rate;
+       return 0;
 }