alistair23-linux/drivers/usb/core/ledtrig-usbport.c
Rafał Miłecki 4f04c210d0 usb: core: read USB ports from DT in the usbport LED trigger driver
This uses DT info to read relation description of LEDs and USB ports. If
DT has properly described LEDs, trigger will know when to turn them on.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-27 17:56:59 +02:00

370 lines
8.9 KiB
C

/*
* USB port LED trigger
*
* Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/device.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/of.h>
struct usbport_trig_data {
struct led_classdev *led_cdev;
struct list_head ports;
struct notifier_block nb;
int count; /* Amount of connected matching devices */
};
struct usbport_trig_port {
struct usbport_trig_data *data;
struct usb_device *hub;
int portnum;
char *port_name;
bool observed;
struct device_attribute attr;
struct list_head list;
};
/***************************************
* Helpers
***************************************/
/**
* usbport_trig_usb_dev_observed - Check if dev is connected to observed port
*/
static bool usbport_trig_usb_dev_observed(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev)
{
struct usbport_trig_port *port;
if (!usb_dev->parent)
return false;
list_for_each_entry(port, &usbport_data->ports, list) {
if (usb_dev->parent == port->hub &&
usb_dev->portnum == port->portnum)
return port->observed;
}
return false;
}
static int usbport_trig_usb_dev_check(struct usb_device *usb_dev, void *data)
{
struct usbport_trig_data *usbport_data = data;
if (usbport_trig_usb_dev_observed(usbport_data, usb_dev))
usbport_data->count++;
return 0;
}
/**
* usbport_trig_update_count - Recalculate amount of connected matching devices
*/
static void usbport_trig_update_count(struct usbport_trig_data *usbport_data)
{
struct led_classdev *led_cdev = usbport_data->led_cdev;
usbport_data->count = 0;
usb_for_each_dev(usbport_data, usbport_trig_usb_dev_check);
led_set_brightness(led_cdev, usbport_data->count ? LED_FULL : LED_OFF);
}
/***************************************
* Device attr
***************************************/
static ssize_t usbport_trig_port_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct usbport_trig_port *port = container_of(attr,
struct usbport_trig_port,
attr);
return sprintf(buf, "%d\n", port->observed) + 1;
}
static ssize_t usbport_trig_port_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct usbport_trig_port *port = container_of(attr,
struct usbport_trig_port,
attr);
if (!strcmp(buf, "0") || !strcmp(buf, "0\n"))
port->observed = 0;
else if (!strcmp(buf, "1") || !strcmp(buf, "1\n"))
port->observed = 1;
else
return -EINVAL;
usbport_trig_update_count(port->data);
return size;
}
static struct attribute *ports_attrs[] = {
NULL,
};
static const struct attribute_group ports_group = {
.name = "ports",
.attrs = ports_attrs,
};
/***************************************
* Adding & removing ports
***************************************/
/**
* usbport_trig_port_observed - Check if port should be observed
*/
static bool usbport_trig_port_observed(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev, int port1)
{
struct device *dev = usbport_data->led_cdev->dev;
struct device_node *led_np = dev->of_node;
struct of_phandle_args args;
struct device_node *port_np;
int count, i;
if (!led_np)
return false;
/* Get node of port being added */
port_np = usb_of_get_child_node(usb_dev->dev.of_node, port1);
if (!port_np)
return false;
/* Amount of trigger sources for this LED */
count = of_count_phandle_with_args(led_np, "trigger-sources",
"#trigger-source-cells");
if (count < 0) {
dev_warn(dev, "Failed to get trigger sources for %s\n",
led_np->full_name);
return false;
}
/* Check list of sources for this specific port */
for (i = 0; i < count; i++) {
int err;
err = of_parse_phandle_with_args(led_np, "trigger-sources",
"#trigger-source-cells", i,
&args);
if (err) {
dev_err(dev, "Failed to get trigger source phandle at index %d: %d\n",
i, err);
continue;
}
of_node_put(args.np);
if (args.np == port_np)
return true;
}
return false;
}
static int usbport_trig_add_port(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev,
const char *hub_name, int portnum)
{
struct led_classdev *led_cdev = usbport_data->led_cdev;
struct usbport_trig_port *port;
size_t len;
int err;
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (!port) {
err = -ENOMEM;
goto err_out;
}
port->data = usbport_data;
port->hub = usb_dev;
port->portnum = portnum;
port->observed = usbport_trig_port_observed(usbport_data, usb_dev,
portnum);
len = strlen(hub_name) + 8;
port->port_name = kzalloc(len, GFP_KERNEL);
if (!port->port_name) {
err = -ENOMEM;
goto err_free_port;
}
snprintf(port->port_name, len, "%s-port%d", hub_name, portnum);
port->attr.attr.name = port->port_name;
port->attr.attr.mode = S_IRUSR | S_IWUSR;
port->attr.show = usbport_trig_port_show;
port->attr.store = usbport_trig_port_store;
err = sysfs_add_file_to_group(&led_cdev->dev->kobj, &port->attr.attr,
ports_group.name);
if (err)
goto err_free_port_name;
list_add_tail(&port->list, &usbport_data->ports);
return 0;
err_free_port_name:
kfree(port->port_name);
err_free_port:
kfree(port);
err_out:
return err;
}
static int usbport_trig_add_usb_dev_ports(struct usb_device *usb_dev,
void *data)
{
struct usbport_trig_data *usbport_data = data;
int i;
for (i = 1; i <= usb_dev->maxchild; i++)
usbport_trig_add_port(usbport_data, usb_dev,
dev_name(&usb_dev->dev), i);
return 0;
}
static void usbport_trig_remove_port(struct usbport_trig_data *usbport_data,
struct usbport_trig_port *port)
{
struct led_classdev *led_cdev = usbport_data->led_cdev;
list_del(&port->list);
sysfs_remove_file_from_group(&led_cdev->dev->kobj, &port->attr.attr,
ports_group.name);
kfree(port->port_name);
kfree(port);
}
static void usbport_trig_remove_usb_dev_ports(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev)
{
struct usbport_trig_port *port, *tmp;
list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
if (port->hub == usb_dev)
usbport_trig_remove_port(usbport_data, port);
}
}
/***************************************
* Init, exit, etc.
***************************************/
static int usbport_trig_notify(struct notifier_block *nb, unsigned long action,
void *data)
{
struct usbport_trig_data *usbport_data =
container_of(nb, struct usbport_trig_data, nb);
struct led_classdev *led_cdev = usbport_data->led_cdev;
struct usb_device *usb_dev = data;
bool observed;
observed = usbport_trig_usb_dev_observed(usbport_data, usb_dev);
switch (action) {
case USB_DEVICE_ADD:
usbport_trig_add_usb_dev_ports(usb_dev, usbport_data);
if (observed && usbport_data->count++ == 0)
led_set_brightness(led_cdev, LED_FULL);
return NOTIFY_OK;
case USB_DEVICE_REMOVE:
usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev);
if (observed && --usbport_data->count == 0)
led_set_brightness(led_cdev, LED_OFF);
return NOTIFY_OK;
}
return NOTIFY_DONE;
}
static void usbport_trig_activate(struct led_classdev *led_cdev)
{
struct usbport_trig_data *usbport_data;
int err;
usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL);
if (!usbport_data)
return;
usbport_data->led_cdev = led_cdev;
/* List of ports */
INIT_LIST_HEAD(&usbport_data->ports);
err = sysfs_create_group(&led_cdev->dev->kobj, &ports_group);
if (err)
goto err_free;
usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports);
usbport_trig_update_count(usbport_data);
/* Notifications */
usbport_data->nb.notifier_call = usbport_trig_notify,
led_cdev->trigger_data = usbport_data;
usb_register_notify(&usbport_data->nb);
led_cdev->activated = true;
return;
err_free:
kfree(usbport_data);
}
static void usbport_trig_deactivate(struct led_classdev *led_cdev)
{
struct usbport_trig_data *usbport_data = led_cdev->trigger_data;
struct usbport_trig_port *port, *tmp;
if (!led_cdev->activated)
return;
list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
usbport_trig_remove_port(usbport_data, port);
}
usb_unregister_notify(&usbport_data->nb);
sysfs_remove_group(&led_cdev->dev->kobj, &ports_group);
kfree(usbport_data);
led_cdev->activated = false;
}
static struct led_trigger usbport_led_trigger = {
.name = "usbport",
.activate = usbport_trig_activate,
.deactivate = usbport_trig_deactivate,
};
static int __init usbport_trig_init(void)
{
return led_trigger_register(&usbport_led_trigger);
}
static void __exit usbport_trig_exit(void)
{
led_trigger_unregister(&usbport_led_trigger);
}
module_init(usbport_trig_init);
module_exit(usbport_trig_exit);
MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>");
MODULE_DESCRIPTION("USB port trigger");
MODULE_LICENSE("GPL v2");