Re: [PATCH] [RFC] HID: udraw: Add support for the uDraw tablet for PS3

[Peter Hutterer <peter.hutterer@who-t.net>]

On Sun, Sep 11, 2016 at 06:48:24PM +0200, Bastien Nocera wrote:
> This adds support for the THQ uDraw tablet for the PS3, as
> 4 separate device nodes, so that user-space can easily consume
> events coming from the hardware.
> 
> Tested-by: Bastien Nocera <hadess@hadess.net>
> Signed-off-by: Bastien Nocera <hadess@hadess.net>
> 
> ---
> 
> I didn't compile it in-tree yet, only out-of-tree, and I'm still
> investigating support for LEDs, battery and better two-finger tap
> support.
> 
> Comments welcome
> 
>  MAINTAINERS             |   6 +
>  drivers/hid/Kconfig     |   7 +
>  drivers/hid/Makefile    |   1 +
>  drivers/hid/hid-core.c  |   1 +
>  drivers/hid/hid-ids.h   |   3 +
>  drivers/hid/hid-udraw.c | 434
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  6 files changed, 452 insertions(+)
>  create mode 100644 drivers/hid/hid-udraw.c
> 

[...]

> diff --git a/drivers/hid/hid-udraw.c b/drivers/hid/hid-udraw.c
> new file mode 100644
> index 0000000..6728cae
> --- /dev/null
> +++ b/drivers/hid/hid-udraw.c
> @@ -0,0 +1,434 @@
> +/*
> + * HID driver for THQ PS3 uDraw tablet
> + *
> + * Copyright (C) 2016 Red Hat Inc. All Rights Reserved
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation,
> and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/hid.h>
> +#include <linux/module.h>
> +#include "hid-ids.h"
> +
> +MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
> +MODULE_DESCRIPTION("PS3 uDraw tablet driver");
> +MODULE_LICENSE("GPL");
> +
> +/*
> + * Protocol information from:
> + * http://brandonw.net/udraw/
> + * and the source code of:
> + * https://vvvv.org/contribution/udraw-hid
> + */
> +
> +/*
> + * The device is setup with multiple input devices to make it easier
> + * to handle in user-space:
> + * - the touch area which works as a touchpad
> + * - the tablet area which works as a touchpad/drawing tablet
> + * - a joypad with a d-pad, and 7 buttons
> + * - an optional, disabled by default, accelerometer device
> + */
> +
> +static const unsigned short udraw_joy_key_table[] = {
> +	BTN_SOUTH,
> +	BTN_NORTH,
> +	BTN_EAST,
> +	BTN_WEST,
> +	BTN_SELECT,
> +	BTN_START,
> +	BTN_MODE
> +};
> +
> +enum {
> +	TOUCH_NONE,
> +	TOUCH_PEN,
> +	TOUCH_FINGER,
> +	TOUCH_FINGERS

FINGER and FINGERS is easy to confuse on a quick read, better rename to
MULTIFINGER or TWOFINGER, depending what you can detect.

> +};
> +
> +/* Accelerometer min/max values
> + * in order, X, Y and Z
> + */
> +struct {
> +	int min;
> +	int max;
> +} accel_limits[] = {
> +	{ 0x1EA, 0x216 },
> +	{ 0x1EA, 0x216 },
> +	{ 0x1EC, 0x218 }
> +};
> +
> +#define DEVICE_NAME "THQ uDraw Game Tablet for PS3"
> +/* resolution in pixels */
> +#define RES_X 1920
> +#define RES_Y 1080
> +/* size in mm */
> +#define WIDTH  160
> +#define HEIGHT 90
> +#define PRESSURE_OFFSET 0x71
> +#define MAX_PRESSURE (0xFF - PRESSURE_OFFSET)
> +
> +struct udraw {
> +	struct input_dev *joy_input_dev;
> +	struct input_dev *touch_input_dev;
> +	struct input_dev *pen_input_dev;
> +	struct input_dev *accel_input_dev;
> +	struct hid_device *hdev;
> +};
> +
> +static int clamp_accel(int axis, int offset)
> +{
> +	axis = clamp(axis,
> +			accel_limits[offset].min,
> +			accel_limits[offset].max);
> +	axis = (axis - accel_limits[offset].min) /
> +			((accel_limits[offset].max -
> +			  accel_limits[offset].min) * 0xFF);
> +	return axis;
> +}
> +
> +static int udraw_raw_event(struct hid_device *hdev, struct hid_report
> *report,
> +	 u8 *data, int len)
> +{
> +	struct udraw *udraw = hid_get_drvdata(hdev);
> +	int touch;
> +	int x, y, z;
> +
> +	if (len != 0x1B)
> +		return 0;
> +
> +	if (data[11] == 0x00)
> +		touch = TOUCH_NONE;
> +	else if (data[11] == 0x40)
> +		touch = TOUCH_PEN;
> +	else if (data[11] == 0x80)
> +		touch = TOUCH_FINGER;
> +	else
> +		touch = TOUCH_FINGERS;
> +
> +	/* joypad */
> +	input_report_key(udraw->joy_input_dev, BTN_WEST, data[0] & 1);
> +	input_report_key(udraw->joy_input_dev, BTN_SOUTH, data[0] &
> 2);
> +	input_report_key(udraw->joy_input_dev, BTN_EAST, data[0] & 4);
> +	input_report_key(udraw->joy_input_dev, BTN_NORTH, data[0] &
> 8);
> +
> +	input_report_key(udraw->joy_input_dev, BTN_SELECT, data[1] &
> 1);
> +	input_report_key(udraw->joy_input_dev, BTN_START, data[1] &
> 2);
> +	input_report_key(udraw->joy_input_dev, BTN_MODE, data[1] &
> 16);
> +
> +	x = y = 0;
> +	switch (data[2]) {
> +	case 0x0:
> +		y = -127;
> +		break;
> +	case 0x1:
> +		y = -127;
> +		x = 127;
> +		break;
> +	case 0x2:
> +		x = 127;
> +		break;
> +	case 0x3:
> +		y = 127;
> +		x = 127;
> +		break;
> +	case 0x4:
> +		y = 127;
> +		break;
> +	case 0x5:
> +		y = 127;
> +		x = -127;
> +		break;
> +	case 0x6:
> +		x = -127;
> +		break;
> +	case 0x7:
> +		y = -127;
> +		x = -127;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	input_report_abs(udraw->joy_input_dev, ABS_X, x);
> +	input_report_abs(udraw->joy_input_dev, ABS_Y, y);
> +
> +	input_sync(udraw->joy_input_dev);
> +
> +	/* For pen and touchpad */
> +	x = y = 0;
> +	if (touch != TOUCH_NONE) {
> +		if (data[15] != 0x0F)
> +			x = data[15] * 256 + data[17];
> +		if (data[16] != 0x0F)
> +			y = data[16] * 256 + data[18];
> +	}
> +
> +	/* touchpad */
> +	if (touch == TOUCH_FINGER || touch == TOUCH_FINGERS) {
> +		input_report_key(udraw->touch_input_dev, BTN_TOUCH,
> 1);
> +		input_report_key(udraw->touch_input_dev,
> BTN_TOOL_FINGER,
> +				touch == TOUCH_FINGER);
> +		input_report_key(udraw->touch_input_dev,
> BTN_TOOL_DOUBLETAP,
> +				touch == TOUCH_FINGERS);
> +
> +		input_report_abs(udraw->touch_input_dev, ABS_X, x);
> +		input_report_abs(udraw->touch_input_dev, ABS_Y, y);
> +	} else {
> +		input_report_key(udraw->touch_input_dev, BTN_TOUCH,
> 0);
> +		input_report_key(udraw->touch_input_dev,
> BTN_TOOL_FINGER, 0);
> +		input_report_key(udraw->touch_input_dev,
> BTN_TOOL_DOUBLETAP, 0);
> +	}
> +	input_sync(udraw->touch_input_dev);
> +
> +	/* pen */
> +	if (touch == TOUCH_PEN) {
> +		int level;
> +
> +		level = clamp(data[13] - PRESSURE_OFFSET,
> +				0, MAX_PRESSURE);
> +
> +		input_report_key(udraw->pen_input_dev, BTN_TOUCH,
> (level != 0));
> +		input_report_key(udraw->pen_input_dev, BTN_TOOL_PEN,
> 1);
> +		input_report_abs(udraw->pen_input_dev, ABS_PRESSURE,
> level);
> +		input_report_abs(udraw->pen_input_dev, ABS_X, x);
> +		input_report_abs(udraw->pen_input_dev, ABS_Y, y);
> +	} else {
> +		input_report_key(udraw->pen_input_dev, BTN_TOUCH, 0);
> +		input_report_abs(udraw->pen_input_dev, ABS_PRESSURE,
> 0);
> +		input_report_key(udraw->pen_input_dev, BTN_TOOL_PEN,
> 0);
> +	}
> +	input_sync(udraw->pen_input_dev);

do me a favour and group the reports by type. it makes no difference to this
driver but event recordings are much easier to read this way.
so all EV_ABS first, then EV_KEY (or the other way round, don't care).

> +
> +	/* accel */
> +	x = (data[19] + (data[20] << 8));
> +	x = clamp_accel(x, 0);
> +	y = (data[21] + (data[22] << 8));
> +	y = clamp_accel(y, 1);
> +	z = (data[23] + (data[24] << 8));
> +	z = clamp_accel(z, 2);

this may not be kernel style, but any reason you can't use an enum here
instead of 0, 1, 2? clamp_accel(x, ACCEL_AXIS_X) would be more obvious to
read.

> +	input_report_abs(udraw->accel_input_dev, ABS_X, x);
> +	input_report_abs(udraw->accel_input_dev, ABS_Y, y);
> +	input_report_abs(udraw->accel_input_dev, ABS_Z, z);
> +	input_sync(udraw->accel_input_dev);
> +
> +	/* let hidraw and hiddev handle the report */
> +	return 0;
> +}
> +
> +static int udraw_open(struct input_dev *dev)
> +{
> +	struct udraw *udraw = input_get_drvdata(dev);
> +
> +	return hid_hw_open(udraw->hdev);
> +}
> +
> +static void udraw_close(struct input_dev *dev)
> +{
> +	struct udraw *udraw = input_get_drvdata(dev);
> +
> +	hid_hw_close(udraw->hdev);
> +}
> +
> +static struct input_dev *allocate_and_setup(struct hid_device *hdev,
> +		const char *name)
> +{
> +	struct input_dev *input_dev;
> +
> +	input_dev = devm_input_allocate_device(&hdev->dev);
> +	if (!input_dev)
> +		return NULL;
> +
> +	input_dev->name = name;
> +	input_dev->phys = hdev->phys;
> +	input_dev->dev.parent = &hdev->dev;
> +	input_dev->open = udraw_open;
> +	input_dev->close = udraw_close;
> +	input_dev->uniq = hdev->uniq;
> +	input_dev->id.bustype = hdev->bus;
> +	input_dev->id.vendor  = hdev->vendor;
> +	input_dev->id.product = hdev->product;
> +	input_dev->id.version = hdev->version;
> +	input_set_drvdata(input_dev, hid_get_drvdata(hdev));
> +
> +	return input_dev;
> +}
> +
> +static bool udraw_setup_touch(struct udraw *udraw,
> +		struct hid_device *hdev)
> +{
> +	struct input_dev *input_dev;
> +
> +	input_dev = allocate_and_setup(hdev, DEVICE_NAME "
> (touchpad)");

no need to use () here. wacom device names are "foo Pen", "foo Finger", etc.
would be nice to continue that naming scheme.

> +	if (!input_dev)
> +		return false;
> +
> +	input_dev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
> +
> +	set_bit(ABS_X, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_X, 0, RES_X, 1, 0);
> +	input_abs_set_res(input_dev, ABS_X, RES_X / WIDTH);
> +	set_bit(ABS_Y, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_Y, 0, RES_Y, 1, 0);
> +	input_abs_set_res(input_dev, ABS_Y, RES_Y / HEIGHT);
> +
> +	set_bit(BTN_TOUCH, input_dev->keybit);
> +	set_bit(BTN_TOOL_FINGER, input_dev->keybit);
> +	set_bit(BTN_TOOL_DOUBLETAP, input_dev->keybit);
> +
> +	set_bit(INPUT_PROP_POINTER, input_dev->propbit);
> +
> +	udraw->touch_input_dev = input_dev;
> +
> +	return true;
> +}
> +
> +static bool udraw_setup_pen(struct udraw *udraw,
> +		struct hid_device *hdev)
> +{
> +	struct input_dev *input_dev;
> +
> +	input_dev = allocate_and_setup(hdev, DEVICE_NAME " (pen)");

see above for naming scheme

> +	if (!input_dev)
> +		return false;
> +
> +	input_dev->evbit[0] = BIT(EV_ABS) | BIT(EV_KEY);
> +
> +	set_bit(ABS_X, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_X, 0, RES_X, 1, 0);
> +	input_abs_set_res(input_dev, ABS_X, RES_X / WIDTH);
> +	set_bit(ABS_Y, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_Y, 0, RES_Y, 1, 0);
> +	input_abs_set_res(input_dev, ABS_Y, RES_Y / HEIGHT);
> +	set_bit(ABS_PRESSURE, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_PRESSURE,
> +			0, MAX_PRESSURE, 0, 0);
> +
> +	set_bit(BTN_TOUCH, input_dev->keybit);
> +	set_bit(BTN_TOOL_PEN, input_dev->keybit);
> +
> +	set_bit(INPUT_PROP_POINTER, input_dev->propbit);
> +
> +	udraw->pen_input_dev = input_dev;
> +
> +	return true;
> +}
> +
> +static bool udraw_setup_accel(struct udraw *udraw,
> +		struct hid_device *hdev)
> +{
> +	struct input_dev *input_dev;
> +
> +	input_dev = allocate_and_setup(hdev, DEVICE_NAME "
> (accelerometer)");

see above for naming scheme

> +	if (!input_dev)
> +		return false;
> +
> +	input_dev->evbit[0] = BIT(EV_ABS);
> +
> +	/* 1G accel is reported as ~256, so clamp to 2G */
> +	set_bit(ABS_X, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_X, -512, 512, 0, 0);
> +	set_bit(ABS_Y, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_Y, -512, 512, 0, 0);
> +	set_bit(ABS_Z, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_Z, -512, 512, 0, 0);
> +
> +	set_bit(INPUT_PROP_ACCELEROMETER, input_dev->propbit);
> +
> +	udraw->accel_input_dev = input_dev;
> +
> +	return true;
> +}
> +
> +static bool udraw_setup_joypad(struct udraw *udraw,
> +		struct hid_device *hdev)
> +{
> +	struct input_dev *input_dev;
> +	int i;
> +
> +	input_dev = allocate_and_setup(hdev, DEVICE_NAME " (joypad)");

see above for naming scheme

> +	if (!input_dev)
> +		return false;
> +
> +	input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
> +
> +	set_bit(ABS_X, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_X, -127, 127, 0, 0);
> +	set_bit(ABS_Y, input_dev->absbit);
> +	input_set_abs_params(input_dev, ABS_Y, -127, 127, 0, 0);
> +
> +	for (i = 0; i < ARRAY_SIZE(udraw_joy_key_table); i++)
> +		set_bit(udraw_joy_key_table[i], input_dev->keybit);

Personal opinion here: for the few buttons you have, the loop over an array
doesn't really get you much benefit over just having 7 set_bit() calls. just
hardcoding all set_bit calls (or moving joy_key_table to here) is that you
have all the init bits in one place for quick analysis.

but I'm not going to argue this point too hard.

Cheers,
   Peter

> +
> +	udraw->joy_input_dev = input_dev;
> +
> +	return true;
> +}
> +
> +static int udraw_probe(struct hid_device *hdev, const struct
> hid_device_id *id)
> +{
> +	struct udraw *udraw;
> +	int ret;
> +
> +	udraw = devm_kzalloc(&hdev->dev, sizeof(struct udraw),
> GFP_KERNEL);
> +	if (!udraw)
> +		return -ENOMEM;
> +
> +	udraw->hdev = hdev;
> +
> +	hid_set_drvdata(hdev, udraw);
> +
> +	ret = hid_parse(hdev);
> +	if (ret) {
> +		hid_err(hdev, "parse failed\n");
> +		return ret;
> +	}
> +
> +	if (!udraw_setup_joypad(udraw, hdev) ||
> +	    !udraw_setup_touch(udraw, hdev) ||
> +	    !udraw_setup_pen(udraw, hdev) ||
> +	    !udraw_setup_accel(udraw, hdev)) {
> +		hid_err(hdev, "could not allocate interfaces\n");
> +		return -ENOMEM;
> +	}
> +
> +	ret = input_register_device(udraw->joy_input_dev) ||
> +		input_register_device(udraw->touch_input_dev) ||
> +		input_register_device(udraw->pen_input_dev) ||
> +		input_register_device(udraw->accel_input_dev);
> +	if (ret) {
> +		hid_err(hdev, "failed to register interfaces\n");
> +		return ret;
> +	}
> +
> +	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW |
> HID_CONNECT_DRIVER);
> +	if (ret) {
> +		hid_err(hdev, "hw start failed\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct hid_device_id udraw_devices[] = {
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_THQ,
> USB_DEVICE_ID_THQ_PS3_UDRAW) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(hid, udraw_devices);
> +
> +static struct hid_driver udraw_driver = {
> +	.name = "hid-udraw",
> +	.id_table = udraw_devices,
> +	.raw_event = udraw_raw_event,
> +	.probe = udraw_probe,
> +};
> +module_hid_driver(udraw_driver);
> -- 
> 2.7.4
> --
> To unsubscribe from this list: send the line "unsubscribe linux-input" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>