linux/drivers/hid/hid-thingm.c
Heiner Kallweit 1d1b564ff8 hid: thingm: reorder calls in thingm_probe
When reviewing another thingm patch Benjamin Tissoires pointed out
the following: "The problem here is that hid_hw_start() is called
before thingm_version() which allows user space to briefly introduce
races between thingm_version() and any hidraw requests.
The mutex will not help here as it is initialized after hid_hw_start()
and only used for protecting the concurrent access of the rgb."

Avoid this possible issue by calling hid_hw_start() later in the
probe function.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-03-15 15:28:55 +01:00

281 lines
6.3 KiB
C

/*
* ThingM blink(1) USB RGB LED driver
*
* Copyright 2013-2014 Savoir-faire Linux Inc.
* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2.
*/
#include <linux/hid.h>
#include <linux/hidraw.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include "hid-ids.h"
#define REPORT_ID 1
#define REPORT_SIZE 9
/* Firmware major number of supported devices */
#define THINGM_MAJOR_MK1 '1'
#define THINGM_MAJOR_MK2 '2'
struct thingm_fwinfo {
char major;
unsigned numrgb;
unsigned first;
};
static const struct thingm_fwinfo thingm_fwinfo[] = {
{
.major = THINGM_MAJOR_MK1,
.numrgb = 1,
.first = 0,
}, {
.major = THINGM_MAJOR_MK2,
.numrgb = 2,
.first = 1,
}
};
/* A red, green or blue channel, part of an RGB chip */
struct thingm_led {
struct thingm_rgb *rgb;
struct led_classdev ldev;
char name[32];
};
/* Basically a WS2812 5050 RGB LED chip */
struct thingm_rgb {
struct thingm_device *tdev;
struct thingm_led red;
struct thingm_led green;
struct thingm_led blue;
u8 num;
};
struct thingm_device {
struct hid_device *hdev;
struct {
char major;
char minor;
} version;
const struct thingm_fwinfo *fwinfo;
struct mutex lock;
struct thingm_rgb *rgb;
};
static int thingm_send(struct thingm_device *tdev, u8 buf[REPORT_SIZE])
{
int ret;
hid_dbg(tdev->hdev, "-> %d %c %02hhx %02hhx %02hhx %02hhx %02hhx %02hhx %02hhx\n",
buf[0], buf[1], buf[2], buf[3], buf[4],
buf[5], buf[6], buf[7], buf[8]);
mutex_lock(&tdev->lock);
ret = hid_hw_raw_request(tdev->hdev, buf[0], buf, REPORT_SIZE,
HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
mutex_unlock(&tdev->lock);
return ret < 0 ? ret : 0;
}
static int thingm_recv(struct thingm_device *tdev, u8 buf[REPORT_SIZE])
{
int ret;
/*
* A read consists of two operations: sending the read command
* and the actual read from the device. Use the mutex to protect
* the full sequence of both operations.
*/
mutex_lock(&tdev->lock);
ret = hid_hw_raw_request(tdev->hdev, buf[0], buf, REPORT_SIZE,
HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
if (ret < 0)
goto err;
ret = hid_hw_raw_request(tdev->hdev, buf[0], buf, REPORT_SIZE,
HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
if (ret < 0)
goto err;
ret = 0;
hid_dbg(tdev->hdev, "<- %d %c %02hhx %02hhx %02hhx %02hhx %02hhx %02hhx %02hhx\n",
buf[0], buf[1], buf[2], buf[3], buf[4],
buf[5], buf[6], buf[7], buf[8]);
err:
mutex_unlock(&tdev->lock);
return ret;
}
static int thingm_version(struct thingm_device *tdev)
{
u8 buf[REPORT_SIZE] = { REPORT_ID, 'v', 0, 0, 0, 0, 0, 0, 0 };
int err;
err = thingm_recv(tdev, buf);
if (err)
return err;
tdev->version.major = buf[3];
tdev->version.minor = buf[4];
return 0;
}
static int thingm_write_color(struct thingm_rgb *rgb)
{
u8 buf[REPORT_SIZE] = { REPORT_ID, 'c', 0, 0, 0, 0, 0, rgb->num, 0 };
buf[2] = rgb->red.ldev.brightness;
buf[3] = rgb->green.ldev.brightness;
buf[4] = rgb->blue.ldev.brightness;
return thingm_send(rgb->tdev, buf);
}
static int thingm_led_set(struct led_classdev *ldev,
enum led_brightness brightness)
{
struct thingm_led *led = container_of(ldev, struct thingm_led, ldev);
int ret;
ret = thingm_write_color(led->rgb);
if (ret)
hid_err(led->rgb->tdev->hdev, "failed to write color\n");
return ret;
}
static int thingm_init_rgb(struct thingm_rgb *rgb)
{
const int minor = ((struct hidraw *) rgb->tdev->hdev->hidraw)->minor;
int err;
/* Register the red diode */
snprintf(rgb->red.name, sizeof(rgb->red.name),
"thingm%d:red:led%d", minor, rgb->num);
rgb->red.ldev.name = rgb->red.name;
rgb->red.ldev.max_brightness = 255;
rgb->red.ldev.brightness_set_blocking = thingm_led_set;
rgb->red.rgb = rgb;
err = devm_led_classdev_register(&rgb->tdev->hdev->dev,
&rgb->red.ldev);
if (err)
return err;
/* Register the green diode */
snprintf(rgb->green.name, sizeof(rgb->green.name),
"thingm%d:green:led%d", minor, rgb->num);
rgb->green.ldev.name = rgb->green.name;
rgb->green.ldev.max_brightness = 255;
rgb->green.ldev.brightness_set_blocking = thingm_led_set;
rgb->green.rgb = rgb;
err = devm_led_classdev_register(&rgb->tdev->hdev->dev,
&rgb->green.ldev);
if (err)
return err;
/* Register the blue diode */
snprintf(rgb->blue.name, sizeof(rgb->blue.name),
"thingm%d:blue:led%d", minor, rgb->num);
rgb->blue.ldev.name = rgb->blue.name;
rgb->blue.ldev.max_brightness = 255;
rgb->blue.ldev.brightness_set_blocking = thingm_led_set;
rgb->blue.rgb = rgb;
err = devm_led_classdev_register(&rgb->tdev->hdev->dev,
&rgb->blue.ldev);
return err;
}
static int thingm_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
struct thingm_device *tdev;
int i, err;
tdev = devm_kzalloc(&hdev->dev, sizeof(struct thingm_device),
GFP_KERNEL);
if (!tdev)
return -ENOMEM;
tdev->hdev = hdev;
hid_set_drvdata(hdev, tdev);
err = hid_parse(hdev);
if (err)
return err;
mutex_init(&tdev->lock);
err = thingm_version(tdev);
if (err)
return err;
hid_dbg(hdev, "firmware version: %c.%c\n",
tdev->version.major, tdev->version.minor);
for (i = 0; i < ARRAY_SIZE(thingm_fwinfo) && !tdev->fwinfo; ++i)
if (thingm_fwinfo[i].major == tdev->version.major)
tdev->fwinfo = &thingm_fwinfo[i];
if (!tdev->fwinfo) {
hid_err(hdev, "unsupported firmware %c\n", tdev->version.major);
return -ENODEV;
}
tdev->rgb = devm_kzalloc(&hdev->dev,
sizeof(struct thingm_rgb) * tdev->fwinfo->numrgb,
GFP_KERNEL);
if (!tdev->rgb)
return -ENOMEM;
err = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
if (err)
return err;
for (i = 0; i < tdev->fwinfo->numrgb; ++i) {
struct thingm_rgb *rgb = tdev->rgb + i;
rgb->tdev = tdev;
rgb->num = tdev->fwinfo->first + i;
err = thingm_init_rgb(rgb);
if (err) {
hid_hw_stop(hdev);
return err;
}
}
return 0;
}
static const struct hid_device_id thingm_table[] = {
{ HID_USB_DEVICE(USB_VENDOR_ID_THINGM, USB_DEVICE_ID_BLINK1) },
{ }
};
MODULE_DEVICE_TABLE(hid, thingm_table);
static struct hid_driver thingm_driver = {
.name = "thingm",
.probe = thingm_probe,
.id_table = thingm_table,
};
module_hid_driver(thingm_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vivien Didelot <vivien.didelot@savoirfairelinux.com>");
MODULE_DESCRIPTION("ThingM blink(1) USB RGB LED driver");