main: Add IIO buffering Light Sensor driver

Such as the one on the Thinkpad Twist

src/Makefile.am

@@ -11,6 +11,7 @@ iio_sensor_proxy_SOURCES =			\
 	drv-fake-light.c			\
 	drv-iio-poll-light.c			\
 	drv-hwmon-light.c			\
+	drv-iio-buffer-light.c			\
 	iio-buffer-utils.h			\
 	iio-buffer-utils.c
 

src/drivers.h

@@ -63,3 +63,4 @@ extern SensorDriver input_accel;
 extern SensorDriver fake_light;
 extern SensorDriver iio_poll_light;
 extern SensorDriver hwmon_light;
+extern SensorDriver iio_buffer_light;

src/drv-iio-buffer-light.c

@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2014 Bastien Nocera <hadess@hadess.net>
+ * Copyright (c) 2015 Elad Alfassa <elad@fedoraproject.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include "drivers.h"
+#include "iio-buffer-utils.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+
+typedef struct {
+	guint              timeout_id;
+	ReadingsUpdateFunc callback_func;
+	gpointer           user_data;
+
+	GUdevDevice *dev;
+	const char *dev_path;
+	int device_id;
+	BufferDrvData *buffer_data;
+} DrvData;
+
+static DrvData *drv_data = NULL;
+
+static int
+process_scan (IIOSensorData data, DrvData *or_data)
+{
+	int i;
+	int level = 0;
+	gboolean present_level;
+	LightReadings readings;
+
+	if (data.read_size < 0) {
+		g_warning ("Couldn't read from device: %s", g_strerror (errno));
+		return 0;
+	}
+
+	/* Rather than read everything:
+	 * for (i = 0; i < data.read_size / or_data->scan_size; i++)...
+	 * Just read the last one */
+	i = (data.read_size / or_data->buffer_data->scan_size) - 1;
+	if (i < 0) {
+		g_debug ("Not enough data to read (read_size: %d scan_size: %d)", (int) data.read_size, or_data->buffer_data->scan_size);
+		return 0;
+	}
+
+	process_scan_1(data.data + or_data->buffer_data->scan_size*i, or_data->buffer_data, "in_intensity_both", &level, &present_level);
+
+	g_debug ("Read from IIO: %d", level);
+	readings.level = level;
+	readings.uses_lux = TRUE;
+
+	//FIXME report errors
+	or_data->callback_func (&iio_buffer_light, (gpointer) &readings, or_data->user_data);
+
+	return 1;
+}
+
+static void
+prepare_output (DrvData    *or_data,
+		const char *dev_dir_name,
+		const char *trigger_name)
+{
+	IIOSensorData data;
+
+	int fp, buf_len = 127;
+
+	data.data = g_malloc(or_data->buffer_data->scan_size * buf_len);
+
+	/* Attempt to open non blocking to access dev */
+	fp = open (or_data->dev_path, O_RDONLY | O_NONBLOCK);
+	if (fp == -1) { /* If it isn't there make the node */
+		g_warning ("Failed to open %s : %s", or_data->dev_path, strerror(errno));
+		goto bail;
+	}
+
+	/* Actually read the data */
+	data.read_size = read (fp, data.data, buf_len * or_data->buffer_data->scan_size);
+	if (data.read_size == -1 && errno == EAGAIN) {
+		g_debug ("No new data available");
+	} else {
+		process_scan(data, or_data);
+	}
+
+	close(fp);
+
+bail:
+	g_free(data.data);
+}
+
+static char *
+get_trigger_name (GUdevDevice *device)
+{
+	GList *devices, *l;
+	GUdevClient *client;
+	gboolean has_trigger = FALSE;
+	char *trigger_name;
+	const gchar * const subsystems[] = { "iio", NULL };
+
+	client = g_udev_client_new (subsystems);
+	devices = g_udev_client_query_by_subsystem (client, "iio");
+
+	/* Find the associated trigger */
+	trigger_name = g_strdup_printf ("als-dev%s", g_udev_device_get_number (device));
+	for (l = devices; l != NULL; l = l->next) {
+		GUdevDevice *dev = l->data;
+
+		if (g_strcmp0 (trigger_name, g_udev_device_get_sysfs_attr (dev, "name")) == 0) {
+			g_debug ("Found associated trigger at %s", g_udev_device_get_sysfs_path (dev));
+			has_trigger = TRUE;
+			break;
+		}
+	}
+
+	g_list_free_full (devices, g_object_unref);
+	g_clear_object (&client);
+
+	if (has_trigger)
+		return trigger_name;
+
+	g_warning ("Could not find trigger name associated with %s",
+		   g_udev_device_get_sysfs_path (device));
+	g_free (trigger_name);
+	return NULL;
+}
+
+static gboolean
+read_light (gpointer user_data)
+{
+	DrvData *data = user_data;
+
+	prepare_output (data, data->buffer_data->dev_dir_name, data->buffer_data->trigger_name);
+
+	return G_SOURCE_CONTINUE;
+}
+
+static gboolean
+iio_buffer_light_discover (GUdevDevice *device)
+{
+	if (g_strcmp0 (g_udev_device_get_subsystem (device), "iio") != 0)
+		return FALSE;
+
+	if (g_strcmp0 ("als", g_udev_device_get_sysfs_attr (device, "name")) != 0)
+		return FALSE;
+
+	g_debug ("Found als at %s", g_udev_device_get_sysfs_path (device));
+	return TRUE;
+}
+
+static gboolean
+iio_buffer_light_open (GUdevDevice        *device,
+                       ReadingsUpdateFunc  callback_func,
+                       gpointer            user_data)
+{
+	char *trigger_name;
+
+	drv_data = g_new0 (DrvData, 1);
+
+	/* Get the trigger name, and build the channels from that */
+	trigger_name = get_trigger_name (device);
+	if (!trigger_name) {
+		g_clear_pointer (&drv_data, g_free);
+		return FALSE;
+	}
+	drv_data->buffer_data = buffer_drv_data_new (device, trigger_name);
+	g_free (trigger_name);
+
+	if (!drv_data->buffer_data) {
+		g_clear_pointer (&drv_data, g_free);
+		return FALSE;
+	}
+
+	drv_data->dev = g_object_ref (device);
+	drv_data->dev_path = g_udev_device_get_device_file (device);
+
+	drv_data->callback_func = callback_func;
+	drv_data->user_data = user_data;
+
+	drv_data->timeout_id = g_timeout_add (700, read_light, drv_data);
+	g_source_set_name_by_id (drv_data->timeout_id, "read_light");
+
+	return TRUE;
+}
+
+static void
+iio_buffer_light_close (void)
+{
+	g_source_remove (drv_data->timeout_id);
+	g_clear_pointer (&drv_data->buffer_data, buffer_drv_data_free);
+	g_clear_object (&drv_data->dev);
+	g_clear_pointer (&drv_data, g_free);
+}
+
+SensorDriver iio_buffer_light = {
+	.name = "IIO Buffer Light sensor",
+	.type = DRIVER_TYPE_LIGHT,
+	.specific_type = DRIVER_TYPE_LIGHT_IIO,
+
+	.discover = iio_buffer_light_discover,
+	.open = iio_buffer_light_open,
+	.close = iio_buffer_light_close,
+};

src/iio-sensor-proxy.c

@@ -87,6 +87,7 @@ static const SensorDriver * const drivers[] = {
 	&iio_poll_accel,
 	&input_accel,
 	&iio_poll_light,
+	&iio_buffer_light,
 	&hwmon_light,
 	&fake_light
 };