/*
* HID Driver for ELAN Touchpad
*
* Currently only supports touchpad found on HP Pavilion X2 10
*
* Copyright (c) 2016 Alexandrov Stanislav <neko@nya.ai>
*
* 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; either version 2 of the License, or (at your option)
* any later version.
*/
#include <linux/hid.h>
#include <linux/input/mt.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/usb.h>
#include "hid-ids.h"
#define ELAN_SINGLE_FINGER 0x81
#define ELAN_MT_FIRST_FINGER 0x82
#define ELAN_MT_SECOND_FINGER 0x83
#define ELAN_INPUT_REPORT_SIZE 8
#define ELAN_MUTE_LED_REPORT 0xBC
#define ELAN_LED_REPORT_SIZE 8
struct elan_touchpad_settings {
u8 max_fingers;
u16 max_x;
u16 max_y;
u8 max_area_x;
u8 max_area_y;
u8 max_w;
int usb_bInterfaceNumber;
};
struct elan_drvdata {
struct input_dev *input;
u8 prev_report[ELAN_INPUT_REPORT_SIZE];
struct led_classdev mute_led;
u8 mute_led_state;
struct elan_touchpad_settings *settings;
};
static int is_not_elan_touchpad(struct hid_device *hdev)
{
struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
return (intf->altsetting->desc.bInterfaceNumber != drvdata->settings->usb_bInterfaceNumber);
}
static int elan_input_mapping(struct hid_device *hdev, struct hid_input *hi,
struct hid_field *field, struct hid_usage *usage,
unsigned long **bit, int *max)
{
if (is_not_elan_touchpad(hdev))
return 0;
if (field->report->id == ELAN_SINGLE_FINGER ||
field->report->id == ELAN_MT_FIRST_FINGER ||
field->report->id == ELAN_MT_SECOND_FINGER)
return -1;
return 0;
}
static int elan_input_configured(struct hid_device *hdev, struct hid_input *hi)
{
int ret;
struct input_dev *input;
struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
if (is_not_elan_touchpad(hdev))
return 0;
input = devm_input_allocate_device(&hdev->dev);
if (!input)
return -ENOMEM;
input->name = "Elan Touchpad";
input->phys = hdev->phys;
input->uniq = hdev->uniq;
input->id.bustype = hdev->bus;
input->id.vendor = hdev->vendor;
input->id.product = hdev->product;
input->id.version = hdev->version;
input->dev.parent = &hdev->dev;
input_set_abs_params(input, ABS_MT_POSITION_X, 0,
drvdata->settings->max_x, 0, 0);
input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
drvdata->settings->max_y, 0, 0);
input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0,
drvdata->settings->max_fingers, 0, 0);
input_set_abs_params(input, ABS_TOOL_WIDTH, 0,
drvdata->settings->max_w, 0, 0);
__set_bit(BTN_LEFT, input->keybit);
__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
ret = input_mt_init_slots(input, drvdata->settings->max_fingers,
INPUT_MT_POINTER);
if (ret) {
hid_err(hdev, "Failed to init elan MT slots: %d\n", ret);
return ret;
}
ret = input_register_device(input);
if (ret) {
hid_err(hdev, "Failed to register elan input device: %d\n",
ret);
input_free_device(input);
return ret;
}
drvdata->input = input;
return 0;
}
static void elan_report_mt_slot(struct elan_drvdata *drvdata, u8 *data,
unsigned int slot_num)
{
struct input_dev *input = drvdata->input;
int x, y, w;
bool active = !!data;
input_mt_slot(input, slot_num);
input_mt_report_slot_state(input, MT_TOOL_FINGER, active);
if (active) {
x = ((data[0] & 0xF0) << 4) | data[1];
y = drvdata->settings->max_y -
(((data[0] & 0x07) << 8) | data[2]);
w = data[4];
input_report_abs(input, ABS_MT_POSITION_X, x);
input_report_abs(input, ABS_MT_POSITION_Y, y);
input_report_abs(input, ABS_TOOL_WIDTH, w);
}
}
static void elan_report_input(struct elan_drvdata *drvdata, u8 *data)
{
int i;
struct input_dev *input = drvdata->input;
/*
* There is 3 types of reports: for single touch,
* for multitouch - first finger and for multitouch - second finger
*
* packet structure for ELAN_SINGLE_FINGER and ELAN_MT_FIRST_FINGER:
*
* byte 1: 1 0 0 0 0 0 0 1 // 0x81 or 0x82
* byte 2: 0 0 0 0 0 0 0 0 // looks like unused
* byte 3: f5 f4 f3 f2 f1 0 0 L
* byte 4: x12 x11 x10 x9 0? y11 y10 y9
* byte 5: x8 x7 x6 x5 x4 x3 x2 x1
* byte 6: y8 y7 y6 y5 y4 y3 y2 y1
* byte 7: sy4 sy3 sy2 sy1 sx4 sx3 sx2 sx1
* byte 8: w8 w7 w6 w5 w4 w3 w2 w1
*
* packet structure for ELAN_MT_SECOND_FINGER:
*
* byte 1: 1 0 0 0 0 0 1 1 // 0x83
* byte 2: x12 x11 x10 x9 0 y11 y10 y9
* byte 3: x8 x7 x6 x5 x4 x3 x2 x1
* byte 4: y8 y7 y6 y5 y4 y3 y2 y1
* byte 5: sy4 sy3 sy2 sy1 sx4 sx3 sx2 sx1
* byte 6: w8 w7 w6 w5 w4 w3 w2 w1
* byte 7: 0 0 0 0 0 0 0 0
* byte 8: 0 0 0 0 0 0 0 0
*
* f5-f1: finger touch bits
* L: clickpad button
* sy / sx: not sure yet, but this looks like rectangular
* area for finger
* w: looks like finger width
*/
if (data[0] == ELAN_SINGLE_FINGER) {
for (i = 0; i < drvdata->settings->max_fingers; i++) {
if (data[2] & BIT(i + 3))
elan_report_mt_slot(drvdata, data + 3, i);
else
elan_report_mt_slot(drvdata, NULL, i);
}
input_report_key(input, BTN_LEFT, data[2] & 0x01);
}
/*
* When touched with two fingers Elan touchpad will emit two HID reports
* first is ELAN_MT_FIRST_FINGER and second is ELAN_MT_SECOND_FINGER
* we will save ELAN_MT_FIRST_FINGER report and wait for
* ELAN_MT_SECOND_FINGER to finish multitouch
*/
if (data[0] == ELAN_MT_FIRST_FINGER) {
memcpy(drvdata->prev_report, data,
sizeof(drvdata->prev_report));
return;
}
if (data[0] == ELAN_MT_SECOND_FINGER) {
int first = 0;
u8 *prev_report = drvdata->prev_report;
if (prev_report[0] != ELAN_MT_FIRST_FINGER)
return;
for (i = 0; i < drvdata->settings->max_fingers; i++) {
if (prev_report[2] & BIT(i + 3)) {
if (!first) {
first = 1;
elan_report_mt_slot(drvdata, prev_report + 3, i);
} else {
elan_report_mt_slot(drvdata, data + 1, i);
}
} else {
elan_report_mt_slot(drvdata, NULL, i);
}
}
input_report_key(input, BTN_LEFT, prev_report[2] & 0x01);
}
input_mt_sync_frame(input);
input_sync(input);
}
static int elan_raw_event(struct hid_device *hdev,
struct hid_report *report, u8 *data, int size)
{
struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
if (is_not_elan_touchpad(hdev))
return 0;
if (data[0] == ELAN_SINGLE_FINGER ||
data[0] == ELAN_MT_FIRST_FINGER ||
data[0] == ELAN_MT_SECOND_FINGER) {
if (size == ELAN_INPUT_REPORT_SIZE) {
elan_report_input(drvdata, data);
return 1;
}
}
return 0;
}
static int elan_start_multitouch(struct hid_device *hdev)
{
int ret;
/*
* This byte sequence will enable multitouch mode and disable
* mouse emulation
*/
const unsigned char buf[] = { 0x0D, 0x00, 0x03, 0x21, 0x00 };
unsigned char *dmabuf = kmemdup(buf, sizeof(buf), GFP_KERNEL);
if (!dmabuf)
return -ENOMEM;
ret = hid_hw_raw_request(hdev, dmabuf[0], dmabuf, sizeof(buf),
HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
kfree(dmabuf);
if (ret != sizeof(buf)) {
hid_err(hdev, "Failed to start multitouch: %d\n", ret);
return ret;
}
return 0;
}
static enum led_brightness elan_mute_led_get_brigtness(struct led_classdev *led_cdev)
{
struct device *dev = led_cdev->dev->parent;
struct hid_device *hdev = to_hid_device(dev);
struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
return drvdata->mute_led_state;
}
static int elan_mute_led_set_brigtness(struct led_classdev *led_cdev,
enum led_brightness value)
{
int ret;
u8 led_state;
struct device *dev = led_cdev->dev->parent;
struct hid_device *hdev = to_hid_device(dev);
struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
unsigned char *dmabuf = kzalloc(ELAN_LED_REPORT_SIZE, GFP_KERNEL);
if (!dmabuf)
return -ENOMEM;
led_state = !!value;
dmabuf[0] = ELAN_MUTE_LED_REPORT;
dmabuf[1] = 0x02;
dmabuf[2] = led_state;
ret = hid_hw_raw_request(hdev, dmabuf[0], dmabuf, ELAN_LED_REPORT_SIZE,
HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
kfree(dmabuf);
if (ret != ELAN_LED_REPORT_SIZE) {
hid_err(hdev, "Failed to set mute led brightness: %d\n", ret);
return ret;
}
drvdata->mute_led_state = led_state;
return 0;
}
static int elan_init_mute_led(struct hid_device *hdev)
{
struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
struct led_classdev *mute_led = &drvdata->mute_led;
mute_led->name = "elan:red:mute";
mute_led->brightness_get = elan_mute_led_get_brigtness;
mute_led->brightness_set_blocking = elan_mute_led_set_brigtness;
mute_led->max_brightness = LED_ON;
mute_led->dev = &hdev->dev;
return devm_led_classdev_register(&hdev->dev, mute_led);
}
static int elan_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
int ret;
struct elan_drvdata *drvdata;
drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
drvdata->settings = (struct elan_touchpad_settings *)id->driver_data;
hid_set_drvdata(hdev, drvdata);
ret = hid_parse(hdev);
if (ret) {
hid_err(hdev, "Hid Parse failed\n");
return ret;
}
ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
if (ret) {
hid_err(hdev, "Hid hw start failed\n");
return ret;
}
if (is_not_elan_touchpad(hdev))
return 0;
if (!drvdata->input) {
hid_err(hdev, "Input device is not registred\n");
ret = -ENAVAIL;
goto err;
}
ret = elan_start_multitouch(hdev);
if (ret)
goto err;
ret = elan_init_mute_led(hdev);
if (ret)
goto err;
return 0;
err:
hid_hw_stop(hdev);
return ret;
}
static void elan_remove(struct hid_device *hdev)
{
hid_hw_stop(hdev);
}
static const struct elan_touchpad_settings hp_x2_10_touchpad_data = {
.max_fingers = 5,
.max_x = 2930,
.max_y = 1250,
.max_area_x = 15,
.max_area_y = 15,
.max_w = 255,
.usb_bInterfaceNumber = 1,
};
static const struct hid_device_id elan_devices[] = {
{ HID_USB_DEVICE(USB_VENDOR_ID_ELAN, USB_DEVICE_ID_HP_X2_10_COVER),
(kernel_ulong_t)&hp_x2_10_touchpad_data},
{ }
};
MODULE_DEVICE_TABLE(hid, elan_devices);
static struct hid_driver elan_driver = {
.name = "elan",
.id_table = elan_devices,
.input_mapping = elan_input_mapping,
.input_configured = elan_input_configured,
.raw_event = elan_raw_event,
.probe = elan_probe,
.remove = elan_remove,
};
module_hid_driver(elan_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexandrov Stanislav");
MODULE_DESCRIPTION("Driver for HID ELAN Touchpads");