linux-kernel - [PATCH v2] usb: typec: Expose Product Type VDOs via sysfs

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Message-Id: <20201022061554.3418060-1-pmalani@chromium.org>
Date:   Wed, 21 Oct 2020 23:15:54 -0700
From:   Prashant Malani <pmalani@...omium.org>
To:     linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        gregkh@...uxfoundation.org
Cc:     Prashant Malani <pmalani@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Subject: [PATCH v2] usb: typec: Expose Product Type VDOs via sysfs

A PD-capable device can return up to 3 Product Type VDOs as part of its
DiscoverIdentity Response (USB PD Spec, Rev 3.0, Version 2.0, Section
6.4.4.3.1). Add a sysfs attribute to expose these to userspace.

Cc: Benson Leung <bleung@...omium.org>
Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Signed-off-by: Prashant Malani <pmalani@...omium.org>
---

NOTE: I didn't include Benson's Reviewed-by from v1, since this version
introduced the sysfs_notify() call.

Changes in v2:
- Added sysfs_notify() call for the attribute.
- Added description for the attribute in
  Documentation/ABI/testing/sysfs-class-typec.

 Documentation/ABI/testing/sysfs-class-typec | 17 +++++++++++++++++
 drivers/usb/typec/class.c                   | 11 +++++++++++
 2 files changed, 28 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
index b834671522d6..16440a236b66 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -170,6 +170,14 @@ Description:
 		will show 0 until Discover Identity command result becomes
 		available. The value can be polled.
 
+What:		/sys/class/typec/<port>-partner/identity/product_type_vdo
+Date:		October 2020
+Contact:	Prashant Malani <pmalani@...omium.org>
+Description:
+		Product Type VDOs part of Discover Identity command result. 3 values
+		are displayed (for the 3 possible Product Type VDOs), one per line.
+		The values will show 0s until Discover Identity command result becomes
+		available. The values can be polled.
 
 USB Type-C cable devices (eg. /sys/class/typec/port0-cable/)
 
@@ -230,6 +238,15 @@ Description:
 		will show 0 until Discover Identity command result becomes
 		available. The value can be polled.
 
+What:		/sys/class/typec/<port>-cable/identity/product_type_vdo
+Date:		October 2020
+Contact:	Prashant Malani <pmalani@...omium.org>
+Description:
+		Product Type VDOs part of Discover Identity command result. 3 values
+		are displayed (for the 3 possible Product Type VDOs), one per line.
+		The values will show 0s until Discover Identity command result becomes
+		available. The values can be polled.
+
 
 USB Type-C port alternate mode devices.
 
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 35eec707cb51..37fa4501e75f 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -122,10 +122,20 @@ static ssize_t product_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(product);
 
+static ssize_t product_type_vdo_show(struct device *dev, struct device_attribute *attr,
+				     char *buf)
+{
+	struct usb_pd_identity *id = get_pd_identity(dev);
+
+	return sprintf(buf, "0x%08x\n0x%08x\n0x%08x\n", id->vdo[0], id->vdo[1], id->vdo[2]);
+}
+static DEVICE_ATTR_RO(product_type_vdo);
+
 static struct attribute *usb_pd_id_attrs[] = {
 	&dev_attr_id_header.attr,
 	&dev_attr_cert_stat.attr,
 	&dev_attr_product.attr,
+	&dev_attr_product_type_vdo.attr,
 	NULL
 };
 
@@ -144,6 +154,7 @@ static void typec_report_identity(struct device *dev)
 	sysfs_notify(&dev->kobj, "identity", "id_header");
 	sysfs_notify(&dev->kobj, "identity", "cert_stat");
 	sysfs_notify(&dev->kobj, "identity", "product");
+	sysfs_notify(&dev->kobj, "identity", "product_type_vdo");
 }
 
 /* ------------------------------------------------------------------------- */
-- 
2.29.0.rc1.297.gfa9743e501-goog