Merge branch 'for-5.17/letsketch' into for-linus

- new driver to support for LetSketch device (Hans de Goede)

4 files changed, 340 insertions, 0 deletions

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index a7c78ac96270..f5544157576c 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -558,6 +558,20 @@ config HID_LENOVO
 	- ThinkPad Compact Bluetooth Keyboard with TrackPoint (supports Fn keys)
 	- ThinkPad Compact USB Keyboard with TrackPoint (supports Fn keys)
 
+config HID_LETSKETCH
+	tristate "Letsketch WP9620N tablets"
+	depends on USB_HID
+	help
+	  Driver for the LetSketch / VSON WP9620N drawing tablet. This
+	  drawing tablet is also sold under other brand names such as Case U,
+	  presumably this driver will work for all of them. But it has only been
+	  tested with a LetSketch WP9620N model.
+
+	  These tablets also work without a special HID driver, but then only
+	  part of the active area works and both the pad and stylus buttons are
+	  hardwired to special key-combos. E.g. the 2 stylus buttons send right
+	  mouse clicks / resp. "e" key presses.
+
 config HID_LOGITECH
 	tristate "Logitech devices"
 	depends on USB_HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 55a6fa3eca5a..6d3e630e81af 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -66,6 +66,7 @@ obj-$(CONFIG_HID_KEYTOUCH)	+= hid-keytouch.o
 obj-$(CONFIG_HID_KYE)		+= hid-kye.o
 obj-$(CONFIG_HID_LCPOWER)	+= hid-lcpower.o
 obj-$(CONFIG_HID_LENOVO)	+= hid-lenovo.o
+obj-$(CONFIG_HID_LETSKETCH)	+= hid-letsketch.o
 obj-$(CONFIG_HID_LOGITECH)	+= hid-logitech.o
 obj-$(CONFIG_HID_LOGITECH)	+= hid-lg-g15.o
 obj-$(CONFIG_HID_LOGITECH_DJ)	+= hid-logitech-dj.o
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index df7bbdf81aa5..26cee452ec44 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -765,6 +765,9 @@
 #define USB_DEVICE_ID_LENOVO_PIXART_USB_MOUSE_602E	0x602e
 #define USB_DEVICE_ID_LENOVO_PIXART_USB_MOUSE_6093	0x6093
 
+#define USB_VENDOR_ID_LETSKETCH		0x6161
+#define USB_DEVICE_ID_WP9620N		0x4d15
+
 #define USB_VENDOR_ID_LG		0x1fd2
 #define USB_DEVICE_ID_LG_MULTITOUCH	0x0064
 #define USB_DEVICE_ID_LG_MELFAS_MT	0x6007
diff --git a/drivers/hid/hid-letsketch.c b/drivers/hid/hid-letsketch.c
new file mode 100644
index 000000000000..74d17cf518ba
--- /dev/null
+++ b/drivers/hid/hid-letsketch.c
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Driver for the LetSketch / VSON WP9620N drawing tablet.
+ * This drawing tablet is also sold under other brand names such as Case U,
+ * presumably this driver will work for all of them. But it has only been
+ * tested with a LetSketch WP9620N model.
+ *
+ * These tablets also work without a special HID driver, but then only part
+ * of the active area works and both the pad and stylus buttons are hardwired
+ * to special key-combos. E.g. the 2 stylus buttons send right mouse clicks /
+ * resp. "e" key presses.
+ *
+ * This device has 4 USB interfaces:
+ *
+ * Interface 0 EP 0x81 bootclass mouse, rdesc len 18, report id 0x08,
+ *                                                    Application(ff00.0001)
+ *  This interface sends raw event input reports in a custom format, but only
+ *  after doing the special dance from letsketch_probe(). After enabling this
+ *  interface the other 3 interfaces are disabled.
+ *
+ * Interface 1 EP 0x82 bootclass mouse, rdesc len 83, report id 0x0a, Tablet
+ *  This interface sends absolute events for the pen, including pressure,
+ *  but only for some part of the active area due to special "aspect ratio"
+ *  correction and only half by default since it assumes it will be used
+ *  with a phone in portraid mode, while using the tablet in landscape mode.
+ *  Also stylus + pad button events are not reported here.
+ *
+ * Interface 2 EP 0x83 bootclass keybd, rdesc len 64, report id none, Std Kbd
+ *  This interfaces send various hard-coded key-combos for the pad buttons
+ *  and "e" keypresses for the 2nd stylus button
+ *
+ * Interface 3 EP 0x84 bootclass mouse, rdesc len 75, report id 0x01, Std Mouse
+ *  This reports right-click mouse-button events for the 1st stylus button
+ */
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/usb.h>
+
+#include <asm/unaligned.h>
+
+#include "hid-ids.h"
+
+#define LETSKETCH_RAW_IF		0
+
+#define LETSKETCH_RAW_DATA_LEN		12
+#define LETSKETCH_RAW_REPORT_ID		8
+
+#define LETSKETCH_PAD_BUTTONS		5
+
+#define LETSKETCH_INFO_STR_IDX_BEGIN	0xc8
+#define LETSKETCH_INFO_STR_IDX_END	0xca
+
+#define LETSKETCH_GET_STRING_RETRIES	5
+
+struct letsketch_data {
+	struct hid_device *hdev;
+	struct input_dev *input_tablet;
+	struct input_dev *input_tablet_pad;
+	struct timer_list inrange_timer;
+};
+
+static int letsketch_open(struct input_dev *dev)
+{
+	struct letsketch_data *data = input_get_drvdata(dev);
+
+	return hid_hw_open(data->hdev);
+}
+
+static void letsketch_close(struct input_dev *dev)
+{
+	struct letsketch_data *data = input_get_drvdata(dev);
+
+	hid_hw_close(data->hdev);
+}
+
+static struct input_dev *letsketch_alloc_input_dev(struct letsketch_data *data)
+{
+	struct input_dev *input;
+
+	input = devm_input_allocate_device(&data->hdev->dev);
+	if (!input)
+		return NULL;
+
+	input->id.bustype = data->hdev->bus;
+	input->id.vendor  = data->hdev->vendor;
+	input->id.product = data->hdev->product;
+	input->id.version = data->hdev->bus;
+	input->phys = data->hdev->phys;
+	input->uniq = data->hdev->uniq;
+	input->open = letsketch_open;
+	input->close = letsketch_close;
+
+	input_set_drvdata(input, data);
+
+	return input;
+}
+
+static int letsketch_setup_input_tablet(struct letsketch_data *data)
+{
+	struct input_dev *input;
+
+	input = letsketch_alloc_input_dev(data);
+	if (!input)
+		return -ENOMEM;
+
+	input_set_abs_params(input, ABS_X, 0, 50800, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, 31750, 0, 0);
+	input_set_abs_params(input, ABS_PRESSURE, 0, 8192, 0, 0);
+	input_abs_set_res(input, ABS_X, 240);
+	input_abs_set_res(input, ABS_Y, 225);
+	input_set_capability(input, EV_KEY, BTN_TOUCH);
+	input_set_capability(input, EV_KEY, BTN_TOOL_PEN);
+	input_set_capability(input, EV_KEY, BTN_STYLUS);
+	input_set_capability(input, EV_KEY, BTN_STYLUS2);
+
+	/* All known brands selling this tablet use WP9620[N] as model name */
+	input->name = "WP9620 Tablet";
+
+	data->input_tablet = input;
+
+	return input_register_device(data->input_tablet);
+}
+
+static int letsketch_setup_input_tablet_pad(struct letsketch_data *data)
+{
+	struct input_dev *input;
+	int i;
+
+	input = letsketch_alloc_input_dev(data);
+	if (!input)
+		return -ENOMEM;
+
+	for (i = 0; i < LETSKETCH_PAD_BUTTONS; i++)
+		input_set_capability(input, EV_KEY, BTN_0 + i);
+
+	/*
+	 * These are never send on the pad input_dev, but must be set
+	 * on the Pad to make udev / libwacom happy.
+	 */
+	input_set_abs_params(input, ABS_X, 0, 1, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, 1, 0, 0);
+	input_set_capability(input, EV_KEY, BTN_STYLUS);
+
+	input->name = "WP9620 Pad";
+
+	data->input_tablet_pad = input;
+
+	return input_register_device(data->input_tablet_pad);
+}
+
+static void letsketch_inrange_timeout(struct timer_list *t)
+{
+	struct letsketch_data *data = from_timer(data, t, inrange_timer);
+	struct input_dev *input = data->input_tablet;
+
+	input_report_key(input, BTN_TOOL_PEN, 0);
+	input_sync(input);
+}
+
+static int letsketch_raw_event(struct hid_device *hdev,
+			       struct hid_report *report,
+			       u8 *raw_data, int size)
+{
+	struct letsketch_data *data = hid_get_drvdata(hdev);
+	struct input_dev *input;
+	int i;
+
+	if (size != LETSKETCH_RAW_DATA_LEN || raw_data[0] != LETSKETCH_RAW_REPORT_ID)
+		return 0;
+
+	switch (raw_data[1] & 0xf0) {
+	case 0x80: /* Pen data */
+		input = data->input_tablet;
+		input_report_key(input, BTN_TOOL_PEN, 1);
+		input_report_key(input, BTN_TOUCH, raw_data[1] & 0x01);
+		input_report_key(input, BTN_STYLUS, raw_data[1] & 0x02);
+		input_report_key(input, BTN_STYLUS2, raw_data[1] & 0x04);
+		input_report_abs(input, ABS_X,
+				 get_unaligned_le16(raw_data + 2));
+		input_report_abs(input, ABS_Y,
+				 get_unaligned_le16(raw_data + 4));
+		input_report_abs(input, ABS_PRESSURE,
+				 get_unaligned_le16(raw_data + 6));
+		/*
+		 * There is no out of range event, so use a timer for this
+		 * when in range we get an event approx. every 8 ms.
+		 */
+		mod_timer(&data->inrange_timer, jiffies + msecs_to_jiffies(100));
+		break;
+	case 0xe0: /* Pad data */
+		input = data->input_tablet_pad;
+		for (i = 0; i < LETSKETCH_PAD_BUTTONS; i++)
+			input_report_key(input, BTN_0 + i, raw_data[4] == (i + 1));
+		break;
+	default:
+		hid_warn(data->hdev, "Warning unknown data header: 0x%02x\n",
+			 raw_data[0]);
+		return 0;
+	}
+
+	input_sync(input);
+	return 0;
+}
+
+/*
+ * The tablets magic handshake to put it in raw mode relies on getting
+ * string descriptors. But the firmware is buggy and does not like it if
+ * we do this too fast. Even if we go slow sometimes the usb_string() call
+ * fails. Ignore errors and retry it a couple of times if necessary.
+ */
+static int letsketch_get_string(struct usb_device *udev, int index, char *buf, int size)
+{
+	int i, ret;
+
+	for (i = 0; i < LETSKETCH_GET_STRING_RETRIES; i++) {
+		usleep_range(5000, 7000);
+		ret = usb_string(udev, index, buf, size);
+		if (ret > 0)
+			return 0;
+	}
+
+	dev_err(&udev->dev, "Max retries (%d) exceeded reading string descriptor %d\n",
+		LETSKETCH_GET_STRING_RETRIES, index);
+	return ret ? ret : -EIO;
+}
+
+static int letsketch_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct device *dev = &hdev->dev;
+	struct letsketch_data *data;
+	struct usb_interface *intf;
+	struct usb_device *udev;
+	char buf[256];
+	int i, ret;
+
+	if (!hid_is_using_ll_driver(hdev, &usb_hid_driver))
+		return -ENODEV;
+
+	intf = to_usb_interface(hdev->dev.parent);
+	if (intf->altsetting->desc.bInterfaceNumber != LETSKETCH_RAW_IF)
+		return -ENODEV; /* Ignore the other interfaces */
+
+	udev = interface_to_usbdev(intf);
+
+	/*
+	 * Instead of using a set-feature request, or even a custom USB ctrl
+	 * message the tablet needs this elaborate magic reading of USB
+	 * string descriptors to kick it into raw mode. This is what the
+	 * Windows drivers are seen doing in an USB trace under Windows.
+	 */
+	for (i = LETSKETCH_INFO_STR_IDX_BEGIN; i <= LETSKETCH_INFO_STR_IDX_END; i++) {
+		ret = letsketch_get_string(udev, i, buf, sizeof(buf));
+		if (ret)
+			return ret;
+
+		hid_info(hdev, "Device info: %s\n", buf);
+	}
+
+	for (i = 1; i <= 250; i++) {
+		ret = letsketch_get_string(udev, i, buf, sizeof(buf));
+		if (ret)
+			return ret;
+	}
+
+	ret = letsketch_get_string(udev, 0x64, buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	ret = letsketch_get_string(udev, LETSKETCH_INFO_STR_IDX_BEGIN, buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	/*
+	 * The tablet should be in raw mode now, end with a final delay before
+	 * doing further IO to the device.
+	 */
+	usleep_range(5000, 7000);
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->hdev = hdev;
+	timer_setup(&data->inrange_timer, letsketch_inrange_timeout, 0);
+	hid_set_drvdata(hdev, data);
+
+	ret = letsketch_setup_input_tablet(data);
+	if (ret)
+		return ret;
+
+	ret = letsketch_setup_input_tablet_pad(data);
+	if (ret)
+		return ret;
+
+	return hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+}
+
+static const struct hid_device_id letsketch_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LETSKETCH, USB_DEVICE_ID_WP9620N) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, letsketch_devices);
+
+static struct hid_driver letsketch_driver = {
+	.name = "letsketch",
+	.id_table = letsketch_devices,
+	.probe = letsketch_probe,
+	.raw_event = letsketch_raw_event,
+};
+module_hid_driver(letsketch_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");