[PATCH] Input - ntrig_spi: add new driver for the Surface 3

[Benjamin Tissoires]

This is a basic driver for the Surface 3. I am not so sure it will work
with any firmwares as most values are encoded, but given that I only have
access to my current device with its firmware and I don't have the
datasheet, it should be OK for now.

The Surface Pen is not supported (if it is supposed to be). I'll work on
this when I get one.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
 drivers/input/touchscreen/Kconfig     |  11 ++
 drivers/input/touchscreen/Makefile    |   1 +
 drivers/input/touchscreen/ntrig_spi.c | 339 ++++++++++++++++++++++++++++++++++
 3 files changed, 351 insertions(+)
 create mode 100644 drivers/input/touchscreen/ntrig_spi.c

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 8ecdc38..22296a4 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -561,6 +561,17 @@ config TOUCHSCREEN_MK712
 	  To compile this driver as a module, choose M here: the
 	  module will be called mk712.
 
+config TOUCHSCREEN_NTRIG_SPI
+	tristate "Ntrig/Microsoft SPI touchscreen"
+	help
+	  Say Y here if you have the Ntrig/Microsoft SPI touchscreen
+	  controller chip as found on the Surface 3 in your system.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ntrig_spi.
+
 config TOUCHSCREEN_HP600
 	tristate "HP Jornada 6xx touchscreen"
 	depends on SH_HP6XX && SH_ADC
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index f42975e..8e04ad1 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_TOUCHSCREEN_MIGOR)		+= migor_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MMS114)	+= mms114.o
 obj-$(CONFIG_TOUCHSCREEN_MTOUCH)	+= mtouch.o
 obj-$(CONFIG_TOUCHSCREEN_MK712)		+= mk712.o
+obj-$(CONFIG_TOUCHSCREEN_NTRIG_SPI)	+= ntrig_spi.o
 obj-$(CONFIG_TOUCHSCREEN_HP600)		+= hp680_ts_input.o
 obj-$(CONFIG_TOUCHSCREEN_HP7XX)		+= jornada720_ts.o
 obj-$(CONFIG_TOUCHSCREEN_IPAQ_MICRO)	+= ipaq-micro-ts.o
diff --git a/drivers/input/touchscreen/ntrig_spi.c b/drivers/input/touchscreen/ntrig_spi.c
new file mode 100644
index 0000000..0d61fc0
--- /dev/null
+++ b/drivers/input/touchscreen/ntrig_spi.c
@@ -0,0 +1,339 @@
+/*
+ *  Driver for Ntrig/Microsoft Touchscreens over SPI
+ *
+ *  Copyright (c) 2016 Red Hat Inc.
+ *
+ */
+
+/*
+ * 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 of the License.
+ */
+
+#include <linux/kernel.h>
+
+#include <asm/unaligned.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/acpi.h>
+
+#define NTRIG_PACKET_SIZE	264
+
+struct ntrig {
+	struct spi_device *spi;
+	struct gpio_desc *gpiod_int;
+	struct gpio_desc *gpiod_rst[2];
+	struct input_dev *input_dev;
+};
+
+struct ntrig_finger {
+	u8 status;
+	u16 tracking_id;
+	u16 x;
+	u16 cx;
+	u16 y;
+	u16 cy;
+	u16 width;
+	u16 height;
+	u32 padding;
+} __packed;
+
+static ssize_t ntrig_spi_read(struct spi_device *spi, char *rxbuf, size_t len)
+{
+	struct spi_message msg;
+	struct spi_transfer xfer;
+	u8 rd_buf[NTRIG_PACKET_SIZE];
+	int err = 0;
+
+	if (!spi)
+		return 0;
+
+	memset(&xfer, 0, sizeof(xfer));
+	memset(rd_buf, 0, sizeof(rd_buf));
+	spi_message_init(&msg);
+
+	xfer.tx_buf = NULL;
+	xfer.len = len;
+	xfer.rx_buf = rd_buf;
+	spi_message_add_tail(&xfer, &msg);
+
+	err = spi_sync(spi, &msg);
+	memcpy(rxbuf, rd_buf, xfer.len);
+
+	return err;
+}
+
+static void ntrig_spi_report_touch(struct ntrig *ntr,
+				   struct ntrig_finger *finger)
+{
+	int st = finger->status & 0x01;
+	int id = get_unaligned_le16(&finger->tracking_id);
+	int  x = get_unaligned_le16(&finger->x);
+	int  y = get_unaligned_le16(&finger->y);
+	int  w = get_unaligned_le16(&finger->width);
+	int  h = get_unaligned_le16(&finger->height);
+	int slot;
+
+	slot = input_mt_get_slot_by_key(ntr->input_dev, id);
+	if (slot < 0)
+		return;
+
+	input_mt_slot(ntr->input_dev, slot);
+	input_mt_report_slot_state(ntr->input_dev, MT_TOOL_FINGER, st);
+	if (st) {
+		input_report_abs(ntr->input_dev, ABS_MT_POSITION_X, x);
+		input_report_abs(ntr->input_dev, ABS_MT_POSITION_Y, y);
+		input_report_abs(ntr->input_dev, ABS_MT_TOUCH_MAJOR, w);
+		input_report_abs(ntr->input_dev, ABS_MT_WIDTH_MAJOR, w);
+		input_report_abs(ntr->input_dev, ABS_MT_TOUCH_MINOR, h);
+		input_report_abs(ntr->input_dev, ABS_MT_WIDTH_MINOR, h);
+	}
+}
+
+static int ntrig_spi_process(struct ntrig *ntr, const char *data)
+{
+	const char header[] = {0xff, 0xff, 0xff, 0xff, 0xa5, 0x5a, 0xe7, 0x7e,
+			       0x01, 0xd2, 0x00, 0x80, 0x01, 0x03, 0x03};
+	u16 timestamp;
+	unsigned int i;
+
+	if (memcmp(header, data, sizeof(header)))
+		dev_err(&ntr->spi->dev, "%s header error: %15ph, ignoring... %s:%d\n",
+			__func__, data, __FILE__, __LINE__);
+
+	timestamp = get_unaligned_le16(&data[15]);
+
+	for (i = 0; i < 13; i++) {
+		struct ntrig_finger *finger;
+
+		finger = (struct ntrig_finger *)&data[17 +
+					       i * sizeof(struct ntrig_finger)];
+
+		if (finger->status & 0x10)
+			break;
+
+		ntrig_spi_report_touch(ntr, finger);
+	}
+
+	input_mt_sync_frame(ntr->input_dev);
+	input_sync(ntr->input_dev);
+	return 0;
+}
+
+static irqreturn_t ntrig_spi_irq_handler(int irq, void *dev_id)
+{
+	struct ntrig *data = dev_id;
+	char spiRxbuf[NTRIG_PACKET_SIZE];
+
+	while (gpiod_get_value(data->gpiod_int)) {
+		memset(spiRxbuf, 0x00, NTRIG_PACKET_SIZE);
+		ntrig_spi_read(data->spi, spiRxbuf, NTRIG_PACKET_SIZE);
+		dev_dbg(&data->spi->dev, "%s received -> %*ph %s:%d\n",
+			__func__, NTRIG_PACKET_SIZE, spiRxbuf,
+			__FILE__, __LINE__);
+		ntrig_spi_process(data, spiRxbuf);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void ntrig_spi_power(struct ntrig *data, unsigned int value)
+{
+	gpiod_set_value(data->gpiod_rst[0], value);
+	gpiod_set_value(data->gpiod_rst[1], value);
+}
+
+/**
+ * ntrig_spi_get_gpio_config - Get GPIO config from ACPI/DT
+ *
+ * @ts: ntrig_spi_ts_data pointer
+ */
+static int ntrig_spi_get_gpio_config(struct ntrig *data)
+{
+	int error;
+	struct device *dev;
+	struct gpio_desc *gpiod;
+	int i;
+
+	if (!data->spi)
+		return -EINVAL;
+
+	dev = &data->spi->dev;
+
+	/* Get the interrupt GPIO pin number */
+	gpiod = devm_gpiod_get_index(dev, NULL, 2, GPIOD_IN);
+	if (IS_ERR(gpiod)) {
+		error = PTR_ERR(gpiod);
+		if (error != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get int GPIO: %d\n", error);
+		return error;
+	}
+
+	data->gpiod_int = gpiod;
+
+	/* Get the reset lines GPIO pin number */
+	for (i = 0; i < 2; i++) {
+		gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_OUT_LOW);
+		if (IS_ERR(gpiod)) {
+			error = PTR_ERR(gpiod);
+			if (error != -EPROBE_DEFER)
+				dev_err(dev,
+					"Failed to get power GPIO %d: %d\n",
+					i,
+					error);
+			return error;
+		}
+
+		data->gpiod_rst[i] = gpiod;
+	}
+
+	return 0;
+}
+
+static int ntrig_spi_create_input(struct ntrig *data)
+{
+	struct input_dev *input;
+	int error;
+
+	input = devm_input_allocate_device(&data->spi->dev);
+	if (IS_ERR(input))
+		return PTR_ERR(input);
+
+	data->input_dev = input;
+
+	input_set_abs_params(input, ABS_MT_POSITION_X, 0, 9600, 0, 0);
+	input_abs_set_res(input, ABS_MT_POSITION_X, 40);
+	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 7200, 0, 0);
+	input_abs_set_res(input, ABS_MT_POSITION_Y, 48);
+	input_set_abs_params(input, ABS_MT_WIDTH_MAJOR, 0, 1024, 0, 0);
+	input_set_abs_params(input, ABS_MT_WIDTH_MINOR, 0, 1024, 0, 0);
+	input_mt_init_slots(input, 10, INPUT_MT_DIRECT);
+
+	input->name = "Ntrig Capacitive TouchScreen";
+	input->phys = "input/ts";
+	input->id.bustype = BUS_SPI;
+	input->id.vendor = 0x1b96;
+	input->id.product = 0x0000;
+	input->id.version = 0x0000;
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(&data->spi->dev,
+			"Failed to register input device: %d", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static void ntrig_spi_free_irq(struct ntrig *data)
+{
+	devm_free_irq(&data->spi->dev, data->spi->irq, data);
+}
+
+static int ntrig_spi_request_irq(struct ntrig *data)
+{
+	struct spi_device *spi = data->spi;
+
+	return devm_request_threaded_irq(&spi->dev, spi->irq,
+					  NULL, ntrig_spi_irq_handler,
+					  IRQ_TYPE_EDGE_RISING | IRQF_ONESHOT,
+					  "Ntrig-irq", data);
+}
+
+static int ntrig_spi_probe(struct spi_device *spi)
+{
+	struct ntrig *data = NULL;
+	int error;
+
+	/* Set up SPI*/
+	spi->bits_per_word = 8;
+	spi->mode = SPI_MODE_0;
+	error = spi_setup(spi);
+	if (error)
+		return error;
+
+	data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
+
+	data->spi = spi;
+	spi_set_drvdata(spi, data);
+
+	error = ntrig_spi_get_gpio_config(data);
+	if (error)
+		return error;
+
+	ntrig_spi_power(data, 1);
+	msleep(20);
+	ntrig_spi_power(data, 0);
+	msleep(20);
+	ntrig_spi_power(data, 1);
+
+	error = ntrig_spi_create_input(data);
+	if (error)
+		return error;
+
+	error = ntrig_spi_request_irq(data);
+	if (error)
+		return error;
+
+	return PTR_ERR_OR_ZERO(data);
+}
+
+static int __maybe_unused ntrig_spi_suspend(struct device *dev)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct ntrig *data = spi_get_drvdata(spi);
+
+	ntrig_spi_free_irq(data);
+
+	ntrig_spi_power(data, 0);
+
+	return 0;
+}
+
+static int __maybe_unused ntrig_spi_resume(struct device *dev)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct ntrig *data = spi_get_drvdata(spi);
+	int error;
+
+	ntrig_spi_power(data, 1);
+
+	error = ntrig_spi_request_irq(data);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(ntrig_spi_pm_ops, ntrig_spi_suspend, ntrig_spi_resume);
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id ntrig_spi_acpi_match[] = {
+	{ "MSHW0037", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, ntrig_spi_acpi_match);
+#endif
+
+static struct spi_driver ntrig_spi_driver = {
+	.driver = {
+		.name	= "Ntrig-spi",
+		.acpi_match_table = ACPI_PTR(ntrig_spi_acpi_match),
+		.pm = &ntrig_spi_pm_ops,
+	},
+	.probe = ntrig_spi_probe,
+};
+
+module_spi_driver(ntrig_spi_driver);
+
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx>");
+MODULE_DESCRIPTION("Ntrig SPI touchscreen driver");
+MODULE_LICENSE("GPL v2");
-- 
2.5.0