From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB7AAC4321D for ; Thu, 23 Aug 2018 18:31:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69E9F21564 for ; Thu, 23 Aug 2018 18:31:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="RGjaQ5tL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 69E9F21564 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727590AbeHWWCk (ORCPT ); Thu, 23 Aug 2018 18:02:40 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:42444 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726985AbeHWWCk (ORCPT ); Thu, 23 Aug 2018 18:02:40 -0400 Received: by mail-pf1-f193.google.com with SMTP id l9-v6so3224376pff.9 for ; Thu, 23 Aug 2018 11:31:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=CJQ6YBPrl6gFzj3eIjWskmozE9vOcWXWtBqmjfcrGkQ=; b=RGjaQ5tLfnGsUPEwJrlWAQkGwTNt3A9J/X0xjQchjRoro5cTXEpg/Mo91DW6h+oAaS cQ9/ORH0yKcO+SOPsPlTG3Bkq1ff2Z9NwjOS84vllSacRlXDBdUtL7VEbJExjFb+wkAg aWTq/hfEqmxyu3Y1KsbVDFq6eku8mJVJ57/CI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=CJQ6YBPrl6gFzj3eIjWskmozE9vOcWXWtBqmjfcrGkQ=; b=VRbG3jaMBPq0fU0SM6hRctAraYF+ivsH+hwJF/RSYSlfaH1/1hlK8re6iJ06mf7DC8 iFcENCXDlNm/w/NI7PXkj2ctTEnAxKyzXlX4BpCdpWGQvgg4M60EKZv6GXwSK3DyefBk Vo+YyRqm+f9W6aac4MEsf8k/48lRfMcVh6nmuiEHZJdpylm16Jca9hk9qq/n3RwuETIk vQ38f0mzOtN9z8kTgIumXlU8Vkzc12/T4HJSM7glogPJ+v89vO/vhY/azizJDJ5ugUpO 4d0QunYnMyEjH4/1xmfz+B5DY3whWFPc9vijhbRv/LgjFu32mGC3ti/IL31tVOJgZje1 OuBw== X-Gm-Message-State: AOUpUlEF/kJMIhWOfJqcejJ5HgwsRub60SRjVd2T14bO+ZuVVuQHmfSx 7GUQdYsGczrFPdRZQtcLxD72rA== X-Google-Smtp-Source: AA+uWPx9ijcMfS+e12cI5pn3/hhJoWw+m1hPY00RFGYKm05aVzPiXmGps/eWVee6oH0hHgKWhxmgRg== X-Received: by 2002:a63:5143:: with SMTP id r3-v6mr57569888pgl.11.1535049102962; Thu, 23 Aug 2018 11:31:42 -0700 (PDT) Received: from kolhar.mtv.corp.google.com ([2620:15c:202:201:356a:9de2:526a:5bc]) by smtp.gmail.com with ESMTPSA id p11-v6sm9054225pfj.72.2018.08.23.11.31.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Aug 2018 11:31:42 -0700 (PDT) From: Harry Cutts To: linux-input , LKML Cc: Jiri Kosina , Dmitry Torokhov , Benjamin Tissoires , Harry Cutts , Jiri Kosina Subject: [PATCH 2/3] Create a utility class for counting scroll events Date: Thu, 23 Aug 2018 11:30:56 -0700 Message-Id: <20180823183057.247630-3-hcutts@chromium.org> X-Mailer: git-send-email 2.18.0.1017.ga543ac7ca45-goog In-Reply-To: <20180823183057.247630-1-hcutts@chromium.org> References: <20180823183057.247630-1-hcutts@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To avoid code duplication, this class counts high-resolution scroll movements and emits the legacy low-resolution events when appropriate. Drivers should create one instance for each scroll wheel that they need to handle. Signed-off-by: Harry Cutts --- drivers/hid/hid-input.c | 44 +++++++++++++++++++++++++++++++++++++++++ include/linux/hid.h | 28 ++++++++++++++++++++++++++ 2 files changed, 72 insertions(+) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 4e94ea3e280a..4ee23b297472 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1826,3 +1826,47 @@ void hidinput_disconnect(struct hid_device *hid) } EXPORT_SYMBOL_GPL(hidinput_disconnect); +/** + * hid_scroll_counter_handle_scroll() - Send high- and low-resolution scroll + * events given a high-resolution wheel + * movement. + * @counter: a hid_scroll_counter struct describing the wheel. + * @hi_res_value: the movement of the wheel, in the mouse's high-resolution + * units. + * + * Given a high-resolution movement, this function converts the movement into + * 256ths of a millimeter and emits high-resolution scroll events for the input + * device. It also uses the multiplier from &struct hid_scroll_counter to emit + * low-resolution scroll events when appropriate for backwards-compatibility + * with userspace input libraries. + */ +void hid_scroll_counter_handle_scroll(struct hid_scroll_counter *counter, + int hi_res_value) +{ + int low_res_scroll_amount; + /* Some wheels often rest 7/8ths of a notch from the previous notch + * after slow movement, so we want the threshold for low-res events in + * between the notches (e.g. after 4/8ths) as opposed to on the notches + * themselves (8/8ths). + */ + int threshold = counter->resolution_multiplier / 2; + + input_report_rel(counter->dev, REL_WHEEL_HI_RES, + hi_res_value * counter->mm256_per_hi_res_unit); + + counter->remainder += hi_res_value; + if (abs(counter->remainder) >= threshold) { + /* Add (or subtract) 1 because we want to trigger when half-way + * to the next notch (i.e. scroll 1 notch after a 1/2 notch + * movement, 2 notches after a 1 1/2 notch movement, etc.). + */ + low_res_scroll_amount = + counter->remainder / counter->resolution_multiplier + + (hi_res_value > 0 ? 1 : -1); + input_report_rel(counter->dev, REL_WHEEL, + low_res_scroll_amount); + counter->remainder -= + low_res_scroll_amount * counter->resolution_multiplier; + } +} +EXPORT_SYMBOL_GPL(hid_scroll_counter_handle_scroll); diff --git a/include/linux/hid.h b/include/linux/hid.h index 834e6461a690..b7bc0b2faf4f 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -1138,6 +1138,34 @@ static inline u32 hid_report_len(struct hid_report *report) int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt); + +/** + * struct hid_scroll_counter - Utility class for processing high-resolution + * scroll events. + * @dev: the input device for which events should be reported. + * @mm256_per_hi_res_unit: the amount moved by the user's finger for each + * high-resolution unit reported by the mouse, in 256ths + * of a millimetre. + * @resolution_multiplier: the wheel's resolution in high-resolution mode as a + * multiple of its lower resolution. For example, if + * moving the wheel by one "notch" would result in a + * value of 1 in low-resolution mode but 8 in + * high-resolution, the multiplier is 8. + * @remainder: counts the number of high-resolution units moved since the last + * low-resolution event (REL_WHEEL or REL_HWHEEL) was sent. Should + * only be used by class methods. + */ +struct hid_scroll_counter { + struct input_dev *dev; + int mm256_per_hi_res_unit; + int resolution_multiplier; + + int remainder; +}; + +void hid_scroll_counter_handle_scroll(struct hid_scroll_counter *counter, + int hi_res_value); + /* HID quirks API */ unsigned long hid_lookup_quirk(const struct hid_device *hdev); int hid_quirks_init(char **quirks_param, __u16 bus, int count); -- 2.18.0.1017.ga543ac7ca45-goog