Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759476Ab2JYOLG (ORCPT ); Thu, 25 Oct 2012 10:11:06 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:46385 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759038Ab2JYOLB (ORCPT ); Thu, 25 Oct 2012 10:11:01 -0400 From: Benjamin Tissoires To: "benjamin.tissoires" , Dmitry Torokhov , Henrik Rydberg , Jiri Kosina , Stephane Chatty , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 01/10] HID: core: fix unit exponent parsing Date: Thu, 25 Oct 2012 16:09:40 +0200 Message-Id: <1351174189-24719-2-git-send-email-benjamin.tissoires@gmail.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1351174189-24719-1-git-send-email-benjamin.tissoires@gmail.com> References: <1351174189-24719-1-git-send-email-benjamin.tissoires@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2917 Lines: 88 HID spec details special values for the HID field unit exponent. Basically, the range [0x8..0xf] correspond to [-8..-1]. Signed-off-by: Benjamin Tissoires --- drivers/hid/hid-core.c | 10 +++++++++- drivers/hid/hid-input.c | 19 +++++++++++++------ 2 files changed, 22 insertions(+), 7 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 5de3bb3..b2533f1 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -315,6 +315,7 @@ static s32 item_sdata(struct hid_item *item) static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) { + __u32 raw_value; switch (item->tag) { case HID_GLOBAL_ITEM_TAG_PUSH: @@ -365,7 +366,14 @@ static int hid_parser_global(struct hid_parser *parser, struct hid_item *item) return 0; case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT: - parser->global.unit_exponent = item_sdata(item); + /* Units exponent negative numbers are given through a special + * table. + * See "6.2.2.7 Global Items" for more information. */ + raw_value = item_udata(item); + if ((raw_value >> 3) == 1) + parser->global.unit_exponent = raw_value - 16; + else + parser->global.unit_exponent = raw_value; return 0; case HID_GLOBAL_ITEM_TAG_UNIT: diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 1b0adc3..fc9f2b5 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -215,7 +215,7 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) field->logical_minimum; __s32 physical_extents = field->physical_maximum - field->physical_minimum; - __s32 prev; + __s32 prev, tmp_exponent; /* Check if the extents are sane */ if (logical_extents <= 0 || physical_extents <= 0) @@ -235,17 +235,24 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code) case ABS_MT_TOOL_Y: case ABS_MT_TOUCH_MAJOR: case ABS_MT_TOUCH_MINOR: - if (field->unit == 0x11) { /* If centimeters */ + if (field->unit & 0xffffff00) /* Not a length */ + return 0; + tmp_exponent = field->unit >> 4; + if ((tmp_exponent >> 3) == 1) + tmp_exponent -= 16; + switch (field->unit & 0xf) { + case 0x1: /* If centimeters */ /* Convert to millimeters */ - unit_exponent += 1; - } else if (field->unit == 0x13) { /* If inches */ + unit_exponent += tmp_exponent; + break; + case 0x3: /* If inches */ /* Convert to millimeters */ prev = physical_extents; physical_extents *= 254; if (physical_extents < prev) return 0; - unit_exponent -= 1; - } else { + unit_exponent += tmp_exponent - 2; + default: return 0; } break; -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/