lib/hidpp20: support feature retrieval

2 files changed, 144 insertions, 6 deletions

diff --git a/lib/hidpp20.c b/lib/hidpp20.c
index 25e7a43..f8a2374 100644
--- a/lib/hidpp20.c
+++ b/lib/hidpp20.c
@@ -20,11 +20,128 @@
 #include <assert.h>
 #include <stddef.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include "debug.h"
 #include "hidpp.h"
 #include "hidpp10.h"
 #include "hidpp20.h"
 
+int hidpp20_get_features_count(int fd, uint8_t device_index,
+                               const FeatureInfo *ifeatureset,
+                               uint8_t *count)
+{
+	int r;
+	HidppMessage req = {
+		.report_id      = HIDPP_SHORT,
+		.device_index   = device_index,
+		.feature_index  = ifeatureset->feature_index,
+		.func           = HIDPP20_FUNC(0),
+	};
+	r = hidpp10_request(fd, &req, NULL, NULL);
+	if (r == 0) {
+		*count = req.params[0];
+	} else {
+		trace_log("[ix=%02x] IFeatureSet.GetCount failed with %#x\n",
+			device_index, r);
+	}
+	return r;
+}
+
+int hidpp20_get_feature(int fd, uint8_t device_index,
+                        const FeatureInfo *ifeatureset,
+                        uint8_t feature_index, FeatureInfo *fi)
+{
+	int r;
+	HidppMessage req = {
+		.report_id      = HIDPP_SHORT,
+		.device_index   = device_index,
+		.feature_index  = ifeatureset->feature_index,
+		.func           = HIDPP20_FUNC(1), /* GetFeatureId */
+		.params         = { feature_index }
+	};
+	assert(device_index >= 1 && device_index <= MAX_DEVICES);
+
+	r = hidpp10_request(fd, &req, NULL, NULL);
+	if (r == 0) {
+		fi->feature_index = feature_index;
+		fi->feature_id = (req.params[0] << 8) | req.params[1];
+		fi->feature_type = req.params[2];
+	} else {
+		trace_log("[ix=%02x] failed to get feature %i, error=%i\n",
+			device_index, feature_index, r);
+	}
+	return r;
+}
+
+int hidpp20_get_feature_by_id(int fd, uint8_t device_index, uint16_t feature_id,
+                              FeatureInfo *fi)
+{
+	int r;
+	HidppMessage req = {
+		.report_id      = HIDPP_SHORT,
+		.device_index   = device_index,
+		.feature_index  = 0x00, /* IRoot */
+		.func           = HIDPP20_FUNC(0), /* GetFeature */
+		.params         = { feature_id >> 8, (uint8_t) feature_id }
+	};
+	assert(device_index >= 1 && device_index <= MAX_DEVICES);
+
+	r = hidpp10_request(fd, &req, NULL, NULL);
+	if (r == 0) {
+		fi->feature_index = req.params[0];
+		fi->feature_id = feature_id;
+		fi->feature_type = req.params[1];
+	} else {
+		trace_log("[ix=%02x] failed to get feature id %#06x, error=%i\n",
+			device_index, feature_id, r);
+	}
+	return r;
+}
+
+FeatureInfo *hidpp20_get_features(int fd, uint8_t device_index, unsigned *count)
+{
+	int r, i;
+	FeatureInfo fi;
+	FeatureInfo *infos;
+	uint8_t count_nonroot; /* features count not including root feature */
+
+	assert(device_index >= 1 && device_index <= MAX_DEVICES);
+
+	*count = 0;
+	r = hidpp20_get_version(fd, device_index);
+	if (r < 0x0200) {
+		trace_log("[ix=%02x] HID++ 2.0 required for features, got %#4x\n",
+			device_index, r);
+		return NULL;
+	}
+
+	r = hidpp20_get_feature_by_id(fd, device_index, 0x0001, &fi);
+	if (r) {
+		trace_log("[ix=%02x] FeatureSet not found, error=%#x\n",
+			device_index, r);
+		return NULL;
+	}
+	r = hidpp20_get_features_count(fd, device_index, &fi, &count_nonroot);
+	if (r)
+		return NULL;
+	infos = calloc(*count, sizeof(FeatureInfo));
+
+	/* infos[0] is the Root feature which has index=0, id=0, type=0 */
+
+	for (i = 1; i <= count_nonroot; i++) {
+		r = hidpp20_get_feature(fd, device_index, &fi, i, &infos[i]);
+		if (r) {
+			trace_log("[ix=%02x] feature %i not found, error=%#x\n",
+				device_index, i, r);
+			free(infos);
+			return NULL;
+		}
+	}
+	/* maybe qsort(infos); here? */
+	*count = count_nonroot + 1;
+	return infos;
+}
+
 uint16_t hidpp20_get_version(int fd, uint8_t device_index)
 {
 	int r;
@@ -33,8 +150,8 @@ uint16_t hidpp20_get_version(int fd, uint8_t device_index)
 	HidppMessage req = {
 		.report_id      = HIDPP_SHORT,
 		.device_index   = device_index,
-		.feature_id     = 0x00,
-		.func           = 0x14,
+		.feature_index  = 0x00, /* IRoot */
+		.func           = HIDPP20_FUNC(1),
 		.params         = { 0, 0, pingData }
 	};
 
diff --git a/lib/hidpp20.h b/lib/hidpp20.h
index 49181e1..696d729 100644
--- a/lib/hidpp20.h
+++ b/lib/hidpp20.h
@@ -39,35 +39,56 @@ typedef struct {
 	uint16_t    feature_id;
 	uint8_t     feature_type;
 } FeatureInfo;
-
+/* TODO: HID++ 1.0 vs 2.0 errors? */
 /**
  * Retrieves the number of HID++ 2.0 features.
  *
  * @param fd        File descriptor of the hidraw device.
+ * @param device_index Device index (between 1 and 6).
+ * @param ifeatureset[in] The IFeatureSet feature to call this method on.
  * @param count[out] The number of HID++ 2.0 features.
  * @return Zero on success, a HID++ error code otherwise.
  */
-int hidpp20_get_features_count(int fd, uint8_t *count);
+int hidpp20_get_features_count(int fd, uint8_t device_index,
+                               const FeatureInfo *ifeatureset,
+                               uint8_t *count);
 
 /**
  * Retrieves feature information from a feature index.
  *
  * @param fd        File descriptor of the hidraw device.
+ * @param device_index Device index (between 1 and 6).
+ * @param ifeatureset[in] The IFeatureSet feature to call this method on.
  * @param feature_index A feature index to find information for.
  * @param fi[out]   Feature information on success.
  * @return Zero on success, a HID++ error code otherwise.
  */
-int hidpp20_get_feature(int fd, uint8_t feature_index, FeatureInfo *fi);
+int hidpp20_get_feature(int fd, uint8_t device_index,
+                        const FeatureInfo *ifeatureset,
+                        uint8_t feature_index, FeatureInfo *fi);
 
 /**
  * Retrieves the feature index for a given feature ID.
  *
  * @param fd        File descriptor of the hidraw device.
+ * @param device_index Device index (between 1 and 6).
  * @param feature_id A 16-bit feature identifier.
  * @param fi[out]   Feature information on success.
  * @return Zero on success, a HID++ error code otherwise.
  */
-int hidpp20_get_feature_by_id(int fd, uint16_t feature_id, FeatureInfo *fi);
+int hidpp20_get_feature_by_id(int fd, uint8_t device_index, uint16_t feature_id,
+                              FeatureInfo *fi);
+
+/**
+ * Retrieves all features of a connected device.
+ *
+ * @param fd        File descriptor of the hidraw device.
+ * @param device_index Device index (between 1 and 6).
+ * @param count[out] The number of discovered features or 0 if an error occured
+ * (in that case, NULL is returned too).
+ * @return NULL on error or an array of features supported by the device.
+ */
+FeatureInfo *hidpp20_get_features(int fd, uint8_t device_index, unsigned *count);
 
 /**
  * Retrieves the HID++ version for the device.