From patchwork Thu May 20 00:22:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kenneth Albanowski X-Patchwork-Id: 444948 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 E85E7C433B4 for ; Thu, 20 May 2021 00:23:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2D2D6008E for ; Thu, 20 May 2021 00:23:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229808AbhETAYk (ORCPT ); Wed, 19 May 2021 20:24:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229525AbhETAYj (ORCPT ); Wed, 19 May 2021 20:24:39 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 808CDC061574 for ; Wed, 19 May 2021 17:23:16 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id s5-20020a252d450000b02905161dc6c7e1so3582490ybe.23 for ; Wed, 19 May 2021 17:23:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=8e4OVut70ZQa0ZDUJJCtb+WnyeU95+VW5Jt/vnIGs1o=; b=bGXRfNP4lhUMkXycO2t4wKMaT6gSoW4u6JS+bnluKieKSni//7PtfFGGatr0fHW+sr Rt61gbxrxKtWAmNxnSHmv/6BE+nQ0gkj5U4LzBB2pstXpqNoqZvhJK0nXHonO0Sx6TXh H7tGhS06Avt4L781wYs+0PEE4YdfXHu42hz4U7KWAnjvvad1gpsZutVSl8UlscZeXA29 XuRTLqnPCSqWOE6qh/fqzRXB/QwP47NPtLGGGDnQK1rxToCVziChNVkgEd9AY0DMZv+Y bd8GVh0xLk43VNrLUPUQ4AvP5gYTeClP9kQLCoZhtDf8N0HV9BicX8OVKxfVRI4/jdqJ HWmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=8e4OVut70ZQa0ZDUJJCtb+WnyeU95+VW5Jt/vnIGs1o=; b=caJX6nMYXsRHmYspBvPz6UvNS3Q6ALlC12jPMJT92LAXlICW+Q/GTTzs/yP52RMEHz +0jd7f5F5gA/+5c4RFX3YqUM8IEQqKrczjGLwJxesD4hmzhf4QLL+n+yn8KZnAFqCfyP 8EEqrZERAMtL5+HK1btug1lgPI4ongzZniw+6ix70tpum8v8+ni4jsPWlke0QSuFTeIa fgQuqpIDvJUuhn9anYsmQiKISb/OgBsPH8ogV8f3qTIvuCqEBVCB08bvw65IJcI+BO3H Fiux4Sqp8BRDViXCW7BR/yhaIrgq8eBewd2GstWtqhdbgzXpPZB0Sx7Es3zAsP21T5lU eUtA== X-Gm-Message-State: AOAM533PWk5QmnkVaqJmecPIlcaYs1Mx+LfVb+3O3PYAR6v/H2MQNIyH KpsF4KJANE0wIeLQv2LEXfAIC43W4CqpHkXdnHg30jme+pZrL3inEp7nWck6Mba645IsTi/e0jw ZwqLR2ON/LyBO8xFIHNX+FPnVrPkYk4vmT6wORvikE4xIcAO67VTEl2SfPEBHACyoIip7DMw= X-Google-Smtp-Source: ABdhPJzAOHna+Qbnxjti5LFCW4HLvYs2ov8fiLSqjr+7T2rYQoGUrRSB44fGLg/r2zF5BxtQnVSKiHuls5g2 X-Received: from kenalba1.mtv.corp.google.com ([2620:15c:203:200:4404:83b2:506f:fd71]) (user=kenalba job=sendgmr) by 2002:a25:b78c:: with SMTP id n12mr3372016ybh.291.1621470195636; Wed, 19 May 2021 17:23:15 -0700 (PDT) Date: Wed, 19 May 2021 17:22:47 -0700 In-Reply-To: <20210520002249.361821-1-kenalba@google.com> Message-Id: <20210519143836.1.I8e23cff04fc537877668462d98d5054bac10d940@changeid> Mime-Version: 1.0 References: <20210520002249.361821-1-kenalba@google.com> X-Mailer: git-send-email 2.31.1.818.g46aad6cb9e-goog Subject: [PATCH 1/3] [hid] Minor cleanup From: Kenneth Albanowski To: "open list:HID CORE LAYER" Cc: Dmitry Torokhov , Benjamin Tissoires , Jiri Kosina , Peter Hutterer , Jason Gerecke , Kenneth Albanowski Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org No functional changes, just cleanup. Clarify actual integer size limits in a few comments. Make one constant explicit to improve readability. Replace open-coded sign-extension with common routine. Signed-off-by: Kenneth Albanowski --- drivers/hid/hid-core.c | 19 +++++++------------ include/linux/hid.h | 3 ++- 2 files changed, 9 insertions(+), 13 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 5b30783e2353d..19b2b0aae0c7e 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -337,7 +337,8 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign } /* - * Read data value from item. + * Read data value from global items, which are + * a maximum of 32 bits in size. */ static u32 item_udata(struct hid_item *item) @@ -709,7 +710,7 @@ static void hid_device_release(struct device *dev) /* * Fetch a report description item from the data stream. We support long - * items, though they are not used yet. + * items, though there are not yet any defined uses for them. */ static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item) @@ -745,6 +746,7 @@ static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item) item->format = HID_ITEM_FORMAT_SHORT; item->size = b & 3; + /* Map size values 0,1,2,3 to actual sizes 0,1,2,4 */ switch (item->size) { case 0: return start; @@ -763,7 +765,7 @@ static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item) return start; case 3: - item->size++; + item->size = 4; if ((end - start) < 4) return NULL; item->data.u32 = get_unaligned_le32(start); @@ -1300,9 +1302,7 @@ int hid_open_report(struct hid_device *device) EXPORT_SYMBOL_GPL(hid_open_report); /* - * Convert a signed n-bit integer to signed 32-bit integer. Common - * cases are done through the compiler, the screwed things has to be - * done by hand. + * Convert a signed n-bit integer to signed 32-bit integer. */ static s32 snto32(__u32 value, unsigned n) @@ -1310,12 +1310,7 @@ static s32 snto32(__u32 value, unsigned n) if (!value || !n) return 0; - switch (n) { - case 8: return ((__s8)value); - case 16: return ((__s16)value); - case 32: return ((__s32)value); - } - return value & (1 << (n - 1)) ? value | (~0U << n) : value; + return sign_extend32(value, n - 1); } s32 hid_snto32(__u32 value, unsigned n) diff --git a/include/linux/hid.h b/include/linux/hid.h index 7a13e9d3441a4..59828a6080e83 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -391,6 +391,7 @@ struct hid_item { struct hid_global { unsigned usage_page; + /* HID Global fields are constrained by spec to 32-bits */ __s32 logical_minimum; __s32 logical_maximum; __s32 physical_minimum; @@ -457,7 +458,7 @@ struct hid_field { unsigned maxusage; /* maximum usage index */ unsigned flags; /* main-item flags (i.e. volatile,array,constant) */ unsigned report_offset; /* bit offset in the report */ - unsigned report_size; /* size of this field in the report */ + unsigned report_size; /* size of this field in the report, in bits */ unsigned report_count; /* number of this field in the report */ unsigned report_type; /* (input,output,feature) */ __s32 *value; /* last known value(s) */