From patchwork Sun Dec 11 19:37:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Badhri Jagan Sridharan X-Patchwork-Id: 633220 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6DAFC4332F for ; Sun, 11 Dec 2022 19:38:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230097AbiLKTiG (ORCPT ); Sun, 11 Dec 2022 14:38:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229475AbiLKTiE (ORCPT ); Sun, 11 Dec 2022 14:38:04 -0500 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77E8C65EC for ; Sun, 11 Dec 2022 11:38:03 -0800 (PST) Received: by mail-pl1-x64a.google.com with SMTP id l10-20020a170902f68a00b00189d1728848so8653461plg.2 for ; Sun, 11 Dec 2022 11:38:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:from:to:cc:subject:date:message-id:reply-to; bh=RgALFf7PGAYeLm7qK7ef+qSJDgWYIBq1PtAWuUeE+QU=; b=EIC/vFnXWam/5mn41nXwqZAMPXeKHbmC3C2uEEyQyGcNwdefXhyEjulzMVKpiE4JBO b9K5G/e95BFG+rWcTR7SK/a4vRA4dfMQW7/TmYRzUxor5ncTOIqiNFciWY51BvuBOog+ FhYaueQUw+lGcpVI9ehSFAi6Njr4gGR8sPxWYQmqN9VjjFikWd1kmZlzSMYR7wEi4/N4 dimcNIXvd63jI7HJHQe+J5sGCZC7L6Bzirsf+QgUIYm+2drZA2Kr+MqFTn7oA/CiW5MX G2B3TGkAYEsFXlhheiOdZIuufLD7Bwn+A+rhSnVvr3ruQS2OIt2ATvuYRmUK+k2bGuA+ 5BIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:from:subject:message-id :mime-version:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=RgALFf7PGAYeLm7qK7ef+qSJDgWYIBq1PtAWuUeE+QU=; b=ZGdawFR6Tbx/UKfAvt0nYMibmDquadKw+sNGqY//5+KKuJRYeMctNz4yt2Qey34nC+ Z8BlQbdYJi3jIj3P+Uvach+H7FFpHHg8s6lz7z58YeoRhEfohzrx8snYfWC2cj7adS1m G3O/OXrfLwdDFNT3enQeNfRofxqBNdzhBsZNBKuYaL6OtDxc9Fh1cfVZN5cEsoIsImRB FspmBBQlsSlBLdPpkdsf3BH+cqgNNBfoY477D5+Sjmd+HF/CCQlYGguNb2s4IJQ20GdW yzhWKKrlffhpPFhkj34SVxXe5kPSEoZEVSZVyjrI19ebbeYcEYVme8Sbf4Y0cVOWtHeJ I8UA== X-Gm-Message-State: ANoB5pmSKK7K0Ra64RXCazwav+ijWSCwS3g9lJEbZRnLnMjFgomO/hwz KSFJrt9ZJSkyO4nU87sFs67evysUDL4= X-Google-Smtp-Source: AA0mqf4rggOLQr7KxGq0jZGUdlpIIBy9rOW/7a4GzvFBOq9RfdaKAuggD+jnCOqt/zwOSp1p2pRMtdhPwAA= X-Received: from badhri.mtv.corp.google.com ([2620:15c:211:201:6e12:1d4:7ea0:48cd]) (user=badhri job=sendgmr) by 2002:a17:90a:2a88:b0:220:1f03:129b with SMTP id j8-20020a17090a2a8800b002201f03129bmr149467pjd.0.1670787482696; Sun, 11 Dec 2022 11:38:02 -0800 (PST) Date: Sun, 11 Dec 2022 11:37:55 -0800 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.0.rc1.256.g54fd8350bd-goog Message-ID: <20221211193755.1392128-1-badhri@google.com> Subject: [PATCH v1] usb: typec: altmodes/displayport: Add hpd sysfs attribute From: Badhri Jagan Sridharan To: Heikki Krogerus , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, RD Babiera , Badhri Jagan Sridharan Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Exporsing HotPlugDetect(HPD) helps userspace to infer HPD state as defined by VESA DisplayPort Alt Mode on USB Type-C Standard. This allows userspace to notify users for self help, for instance, to hint user that the display port cable is probably detached (or) the display port sink (viz., monitors ect.,) is un-powered. Also helps to debug issues reported from field. This change adds an additional attribute "hpd" to the existing "displayport" attributes. VESA DisplayPort Alt Mode on USB Type-C Standard defines how HotPlugDetect(HPD) shall be supported on the USB-C connector when operating in DisplayPort Alt Mode. This is a read only node which reflects the current state of HPD. Valid values: - 1 when HPD’s logical state is high (HPD_High) - 0 when HPD’s logical state is low (HPD_Low) Signed-off-by: Badhri Jagan Sridharan Reviewed-by: Heikki Krogerus --- .../ABI/testing/sysfs-driver-typec-displayport | 15 +++++++++++++++ drivers/usb/typec/altmodes/displayport.c | 10 ++++++++++ 2 files changed, 25 insertions(+) base-commit: 81c25247a2a03a0f97e4805d7aff7541ccff6baa diff --git a/Documentation/ABI/testing/sysfs-driver-typec-displayport b/Documentation/ABI/testing/sysfs-driver-typec-displayport index 231471ad0d4b..256c87c5219a 100644 --- a/Documentation/ABI/testing/sysfs-driver-typec-displayport +++ b/Documentation/ABI/testing/sysfs-driver-typec-displayport @@ -47,3 +47,18 @@ Description: USB SuperSpeed protocol. From user perspective pin assignments C and E are equal, where all channels on the connector are used for carrying DisplayPort protocol (allowing higher resolutions). + +What: /sys/bus/typec/devices/.../displayport/hpd +Date: Dec 2022 +Contact: Badhri Jagan Sridharan +Description: + VESA DisplayPort Alt Mode on USB Type-C Standard defines how + HotPlugDetect(HPD) shall be supported on the USB-C connector when + operating in DisplayPort Alt Mode. This is a read only node which + reflects the current state of HPD. + + Valid values: + - 1: when HPD’s logical state is high (HPD_High) as defined + by VESA DisplayPort Alt Mode on USB Type-C Standard. + - 0 when HPD’s logical state is low (HPD_Low) as defined by + VESA DisplayPort Alt Mode on USB Type-C Standard. diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c index de66a2949e33..06fb4732f8cd 100644 --- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -146,6 +146,7 @@ static int dp_altmode_status_update(struct dp_altmode *dp) if (dp->hpd != hpd) { drm_connector_oob_hotplug_event(dp->connector_fwnode); dp->hpd = hpd; + sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd"); } } @@ -508,9 +509,18 @@ static ssize_t pin_assignment_show(struct device *dev, } static DEVICE_ATTR_RW(pin_assignment); +static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct dp_altmode *dp = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d\n", dp->hpd); +} +static DEVICE_ATTR_RO(hpd); + static struct attribute *dp_altmode_attrs[] = { &dev_attr_configuration.attr, &dev_attr_pin_assignment.attr, + &dev_attr_hpd.attr, NULL };