[RFC PATCH 3/3] usb: typec: Expose Product Type VDOs via sysfs

[Heikki Krogerus]

From: Prashant Malani <pmal...@chromium.org>

Interim. ABI doc missing.

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 sysfs attribute to expose these to userspace.

Signed-off-by: Prashant Malani <pmal...@chromium.org>
[ heikki: Only one instead of three attribute files ]
Signed-off-by: Heikki Krogerus <heikki.kroge...@linux.intel.com>'
---
 drivers/usb/typec/class.c | 41 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 303f054181ff7..5e135678f5952 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -165,15 +165,55 @@ 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);
+       size_t len = 0;
+       int i;
+
+       for (i = 0; i < 3; i++) {
+               if (!id->vdo[i])
+                       break;
+               len += sysfs_emit(buf, "%08x ", id->vdo[i]);
+       }
+
+       buf[len - 1] = '\n';
+
+       return len;
+}
+
+static struct device_attribute dev_attr_product_type_vdo = {
+       .attr = {
+               .name = "product_type",
+               .mode = 0444,
+       },
+       .show = product_type_vdo_show,
+};
+
+static umode_t
+typec_identity_attr_is_visible(struct kobject *kobj, struct attribute *attr, 
int n)
+{
+       struct usb_pd_identity *id = get_pd_identity(kobj_to_dev(kobj));
+
+       if (attr == &dev_attr_product_type_vdo.attr &&
+           !id->vdo[0])
+               return 0;
+
+       return attr->mode;
+}
+
 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
 };
 
 static const struct attribute_group usb_pd_id_group = {
        .name = "identity",
+       .is_visible = typec_identity_attr_is_visible,
        .attrs = usb_pd_id_attrs,
 };
 
@@ -191,6 +231,7 @@ static void typec_product_type_notify(struct device *dev)
        if (!ptype)
                return;
 
+       sysfs_notify(&dev->kobj, "identity", "product_type");
        sysfs_notify(&dev->kobj, NULL, "product_type");
 
        envp[0] = kasprintf(GFP_KERNEL, "PRODUCT_TYPE=%s", ptype);
-- 
2.29.2