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usb: pd: Exposing the Peak Current value of Fixed Supplies to user space 

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 <dgilbert@interlog.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20231002142240.2641962-1-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heikki Krogerus 2023-10-02 17:22:40 +03:00 committed by Greg Kroah-Hartman
parent b447e9efe5
commit 568441b7d4
3 changed files with 12 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
Documentation/ABI/testing/sysfs-class-usb_power_delivery
View File

@ -124,6 +124,13 @@ Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Description:
The voltage the supply supports in millivolts.
What: /sys/class/usb_power_delivery/.../source-capabilities/<position>:fixed_supply/peak_current
Date: October 2023
Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Description:
This file shows the value of the Fixed Power Source Peak Current
Capability field.
What: /sys/class/usb_power_delivery/.../source-capabilities/<position>:fixed_supply/maximum_current
Date: May 2022
Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com>

10
drivers/usb/typec/pd.c
View File

@ -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)

1
include/linux/usb/pd.h
View File

@ -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 */