[PATCH v4 3/4] HID: logitech: Add feature 0x0001: FeatureSet

From: Mazin Rezk
Date: Thu Oct 10 2019 - 20:57:41 EST


On Saturday, October 5, 2019 9:04 PM, Mazin Rezk <mnrzk@xxxxxxxxxxxxxx> wrote:

> This patch adds support for the 0x0001 (FeatureSet) feature. This feature
> is used to look up the feature ID of a feature index on a device and list
> the total count of features on the device.
>
> I also added the hidpp20_get_features function which iterates through all
> feature indexes on the device and stores a map of them in features an
> hidpp_device struct. This function runs when an HID++ 2.0 device is probed.

Changes in the version:
- Renamed hidpp20_featureset_get_feature to
hidpp20_featureset_get_feature_id.

- Re-ordered hidpp20_featureset_get_count and
hidpp20_featureset_get_feature_id based on their command IDs.

- Made feature_count initialize to 0 before running hidpp20_get_features.

Signed-off-by: Mazin Rezk <mnrzk@xxxxxxxxxxxxxx>
---
drivers/hid/hid-logitech-hidpp.c | 90 ++++++++++++++++++++++++++++++++
1 file changed, 90 insertions(+)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index a0efa8a43213..2062be922c08 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -190,6 +190,9 @@ struct hidpp_device {

struct hidpp_battery battery;
struct hidpp_scroll_counter vertical_wheel_counter;
+
+ u16 *features;
+ u8 feature_count;
};

/* HID++ 1.0 error codes */
@@ -911,6 +914,82 @@ static int hidpp_root_get_protocol_version(struct hidpp_device *hidpp)
return 0;
}

+/* -------------------------------------------------------------------------- */
+/* 0x0001: FeatureSet */
+/* -------------------------------------------------------------------------- */
+
+#define HIDPP_PAGE_FEATURESET 0x0001
+
+#define CMD_FEATURESET_GET_COUNT 0x00
+#define CMD_FEATURESET_GET_FEATURE 0x11
+
+static int hidpp20_featureset_get_count(struct hidpp_device *hidpp,
+ u8 feature_index, u8 *count)
+{
+ struct hidpp_report response;
+ int ret;
+
+ ret = hidpp_send_fap_command_sync(hidpp, feature_index,
+ CMD_FEATURESET_GET_COUNT, NULL, 0, &response);
+
+ if (ret)
+ return ret;
+
+ *count = response.fap.params[0];
+
+ return ret;
+}
+
+static int hidpp20_featureset_get_feature_id(struct hidpp_device *hidpp,
+ u8 featureset_index, u8 feature_index, u16 *feature_id)
+{
+ struct hidpp_report response;
+ int ret;
+
+ ret = hidpp_send_fap_command_sync(hidpp, featureset_index,
+ CMD_FEATURESET_GET_FEATURE, &feature_index, 1, &response);
+
+ if (ret)
+ return ret;
+
+ *feature_id = (response.fap.params[0] << 8) | response.fap.params[1];
+
+ return ret;
+}
+
+static int hidpp20_get_features(struct hidpp_device *hidpp)
+{
+ int ret;
+ u8 featureset_index, featureset_type;
+ u8 i;
+
+ ret = hidpp_root_get_feature(hidpp, HIDPP_PAGE_FEATURESET,
+ &featureset_index, &featureset_type);
+
+ if (ret == -ENOENT) {
+ hid_warn(hidpp->hid_dev, "Unable to retrieve feature set.");
+ return 0;
+ }
+
+ if (ret)
+ return ret;
+
+ ret = hidpp20_featureset_get_count(hidpp, featureset_index,
+ &hidpp->feature_count);
+
+ if (ret)
+ return ret;
+
+ hidpp->features = devm_kzalloc(&hidpp->hid_dev->dev,
+ hidpp->feature_count * sizeof(u16), GFP_KERNEL);
+
+ for (i = 0; i < hidpp->feature_count && !ret; i++)
+ ret = hidpp20_featureset_get_feature_id(hidpp, featureset_index,
+ i, &(hidpp->features[i]));
+
+ return ret;
+}
+
/* -------------------------------------------------------------------------- */
/* 0x0005: GetDeviceNameType */
/* -------------------------------------------------------------------------- */
@@ -3625,6 +3704,17 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
hidpp_overwrite_name(hdev);
}

+ /* Cache feature indexes and IDs to check reports faster */
+ hidpp->feature_count = 0;
+
+ if (hidpp->protocol_major >= 2) {
+ if (hidpp20_get_features(hidpp)) {
+ hid_err(hdev, "%s:hidpp20_get_features returned error\n",
+ __func__);
+ goto hid_hw_init_fail;
+ }
+ }
+
if (connected && (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP)) {
ret = wtp_get_config(hidpp);
if (ret)
--
2.23.0