Commit 568441b7 authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman
Browse files

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: default avatarDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20231002142240.2641962-1-heikki.krogerus@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b447e9ef

Documentation/ABI/testing/sysfs-class-usb_power_delivery

+7 −0
Original line number Diff line number Diff line
@@ -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>

drivers/usb/typec/pd.c

+4 −6
Original line number Diff line number Diff line
@@ -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)

include/linux/usb/pd.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */