From patchwork Mon Oct 2 14:22:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heikki Krogerus X-Patchwork-Id: 13406284 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1650C199AF for ; Mon, 2 Oct 2023 14:22:46 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A14EBA4 for ; Mon, 2 Oct 2023 07:22:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1696256564; x=1727792564; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=YbWXFvzQZoqXdqd/6sX/f9t0eK5BwQKXDGFlF8bdmPw=; b=nxYLcj1NXH1U7dTeg+eqZybFQKYlNm5qDCsBeuksRJi6c4cbXzdyz6PI idoja/TZfOgtEVhBQpuugZNMU96DsPVI1Ikh4iwMMdBI1JpUgi76psZXm tmyLoNV4a7UE40s4SPSSHERTw3t3D0XLtNsm+UPMceyPLOwvIGf4lAqyB 28W0w30vqOo+rNUH6Crrlksq55maAhdYVvcPkkY/fWVq+OiGvfgr20+0I bUtb5BoXTzKpbCQgXjNLH1bdYsmO3svXLjFAR0tBQN/lc8x7e9+CQN3Xl qieFLOHQ2p39KJAeRrUZa5TrqJ0NZSQ+Yo0Ei3toEkYtP5wSa03WXk2iS A==; X-IronPort-AV: E=McAfee;i="6600,9927,10851"; a="413563270" X-IronPort-AV: E=Sophos;i="6.03,194,1694761200"; d="scan'208";a="413563270" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Oct 2023 07:22:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10851"; a="894143281" X-IronPort-AV: E=Sophos;i="6.03,194,1694761200"; d="scan'208";a="894143281" Received: from black.fi.intel.com (HELO black.fi.intel.com.) ([10.237.72.28]) by fmsmga001.fm.intel.com with ESMTP; 02 Oct 2023 07:21:20 -0700 From: Heikki Krogerus To: Greg Kroah-Hartman Cc: Guenter Roeck , linux-usb@vger.kernel.org, Douglas Gilbert Subject: [PATCH v3] usb: pd: Exposing the Peak Current value of Fixed Supplies to user space Date: Mon, 2 Oct 2023 17:22:40 +0300 Message-Id: <20231002142240.2641962-1-heikki.krogerus@linux.intel.com> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-4.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Exposing the value of the field as is. The Peak Current value has to be interpreted as described in Table 6-10 (Fixed Power Source Peak Current Capability) of the USB Power Delivery Specification, but that interpretation will be done in user space, not in kernel. Suggested-by: Douglas Gilbert Reviewed-by: Guenter Roeck Signed-off-by: Heikki Krogerus --- v3: There was something wrong with my reStructuredText style table. While attempting to fix it, I realised that in the latest USB PD specification there are some small changes in the Table 6-10, so I'm skipping that table from the documentation, and just giving a general explanation for the sysfs file instead. I took the liberty of including Reviewed-by tag from Guenter in any case. The code has not changed. --- .../ABI/testing/sysfs-class-usb_power_delivery | 7 +++++++ drivers/usb/typec/pd.c | 10 ++++------ include/linux/usb/pd.h | 1 + 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-class-usb_power_delivery b/Documentation/ABI/testing/sysfs-class-usb_power_delivery index 1bf9d1d7902c..61d233c320ea 100644 --- a/Documentation/ABI/testing/sysfs-class-usb_power_delivery +++ b/Documentation/ABI/testing/sysfs-class-usb_power_delivery @@ -124,6 +124,13 @@ Contact: Heikki Krogerus Description: The voltage the supply supports in millivolts. +What: /sys/class/usb_power_delivery/.../source-capabilities/:fixed_supply/peak_current +Date: October 2023 +Contact: Heikki Krogerus +Description: + This file shows the value of the Fixed Power Source Peak Current + Capability field. + What: /sys/class/usb_power_delivery/.../source-capabilities/:fixed_supply/maximum_current Date: May 2022 Contact: Heikki Krogerus diff --git a/drivers/usb/typec/pd.c b/drivers/usb/typec/pd.c index 8cc66e4467c4..85d015cdbe1f 100644 --- a/drivers/usb/typec/pd.c +++ b/drivers/usb/typec/pd.c @@ -83,14 +83,12 @@ unchunked_extended_messages_supported_show(struct device *dev, } static DEVICE_ATTR_RO(unchunked_extended_messages_supported); -/* - * REVISIT: Peak Current requires access also to the RDO. static ssize_t peak_current_show(struct device *dev, struct device_attribute *attr, char *buf) { - ... + return sysfs_emit(buf, "%u\n", (to_pdo(dev)->pdo >> PDO_FIXED_PEAK_CURR_SHIFT) & 3); } -*/ +static DEVICE_ATTR_RO(peak_current); static ssize_t fast_role_swap_current_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -135,7 +133,7 @@ static struct attribute *source_fixed_supply_attrs[] = { &dev_attr_usb_communication_capable.attr, &dev_attr_dual_role_data.attr, &dev_attr_unchunked_extended_messages_supported.attr, - /*&dev_attr_peak_current.attr,*/ + &dev_attr_peak_current.attr, &dev_attr_voltage.attr, &maximum_current_attr.attr, NULL @@ -144,7 +142,7 @@ static struct attribute *source_fixed_supply_attrs[] = { static umode_t fixed_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n) { if (to_pdo(kobj_to_dev(kobj))->object_position && - /*attr != &dev_attr_peak_current.attr &&*/ + attr != &dev_attr_peak_current.attr && attr != &dev_attr_voltage.attr && attr != &maximum_current_attr.attr && attr != &operational_current_attr.attr) diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h index c59fb79a42e8..eb626af0e4e7 100644 --- a/include/linux/usb/pd.h +++ b/include/linux/usb/pd.h @@ -228,6 +228,7 @@ enum pd_pdo_type { #define PDO_FIXED_UNCHUNK_EXT BIT(24) /* Unchunked Extended Message supported (Source) */ #define PDO_FIXED_FRS_CURR_MASK (BIT(24) | BIT(23)) /* FR_Swap Current (Sink) */ #define PDO_FIXED_FRS_CURR_SHIFT 23 +#define PDO_FIXED_PEAK_CURR_SHIFT 20 #define PDO_FIXED_VOLT_SHIFT 10 /* 50mV units */ #define PDO_FIXED_CURR_SHIFT 0 /* 10mA units */