[PATCH 1/1] Added support for Microchip Projected Capacitive Touchscreen controllers for UART communications

[Steve Grahovac <steve.grahovac@gmail.com>]

From: Steve Grahovac <steve.grahovac@microchip.com>


Signed-off-by: Steve Grahovac <steve.grahovac@microchip.com>
---
 drivers/input/touchscreen/Kconfig      |   10 ++
 drivers/input/touchscreen/Makefile     |    1 +
 drivers/input/touchscreen/mchppcapmt.c |  263 ++++++++++++++++++++++++++++++++
 include/linux/serio.h                  |    1 +
 4 files changed, 275 insertions(+), 0 deletions(-)
 create mode 100755 drivers/input/touchscreen/mchppcapmt.c

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 400c99d..e69ec50 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -648,4 +648,14 @@ config TOUCHSCREEN_STMPE
 	  To compile this driver as a module, choose M here: the
 	  module will be called stmpe-ts.
 
+config TOUCHSCREEN_MCHPPCAP
+	tristate "Microchip PCAP touchscreen"
+	select SERIO
+	help
+	  Say Y here if you have a Microchip PCAP Controller and
+	  want to enable support for the built-in touchscreen.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mchippcap.
+
 endif
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 22e2d59..9575478 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -53,3 +53,4 @@ obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE)	+= mainstone-wm97xx.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_ZYLONITE)	+= zylonite-wm97xx.o
 obj-$(CONFIG_TOUCHSCREEN_W90X900)	+= w90p910_ts.o
 obj-$(CONFIG_TOUCHSCREEN_TPS6507X)	+= tps6507x-ts.o
+obj-$(CONFIG_TOUCHSCREEN_MCHPPCAP)	+= mchppcapmt.o
diff --git a/drivers/input/touchscreen/mchppcapmt.c b/drivers/input/touchscreen/mchppcapmt.c
new file mode 100755
index 0000000..047a4d0
--- /dev/null
+++ b/drivers/input/touchscreen/mchppcapmt.c
@@ -0,0 +1,263 @@
+/*
+ * Microchip Serial Touchscreen Driver
+ *
+ * Copyright (c) 2010 Microchip Technology, Inc.
+ *
+ * http://www.microchip.com/mtouch
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+/*
+ * This driver can handle serial Microchip controllers using the Projected
+ * Capacitive 5-byte protocol
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+#include <linux/init.h>
+#include <linux/ctype.h>
+
+#define DRIVER_DESC "Microchip Project Capacitive Serial Touchscreen Driver"
+
+MODULE_AUTHOR("Steve Grahovac <steve.grahovac@microchip.com>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/*
+ * Definitions & global arrays.
+ */
+
+#define MCHIP_MAX_LENGTH	5
+
+/*
+ * Per-touchscreen controller data.
+ */
+
+struct mchip {
+	struct input_dev *dev;
+	struct serio *serio;
+	int id;
+	int index;
+	unsigned char data[MCHIP_MAX_LENGTH];
+	char phys[32];
+};
+
+static void mchppcap_process_data(struct mchip *mchip, unsigned char data)
+{
+	struct input_dev *dev = mchip->dev;
+
+	mchip->data[mchip->index] = data;
+
+	/****************************************************
+	Data format, 5 bytes: SYNC, DATA1, DATA2, DATA3, DATA4
+	SYNC [7:0]: 1,TOUCHID[6:5],0,0,TOUCHSTATUS[2:0]
+	DATA1[7:0]: 0,X-LOW[6:0]
+	DATA2[7:0]: 0,X-HIGH[2:0]
+	DATA3[7:0]: 0,Y-LOW[6:0]
+	DATA4[7:0]: 0,Y-HIGH[2:0]
+	TOUCHSTATUS: 0 = Touch up, 1 = Touch down
+	****************************************************/
+	switch (mchip->index++) {
+	case 0:
+		/* Verify if sync bit is set for the first byte of packet */
+		if (!(0x80 & data))
+			mchip->index = 0;
+		break;
+
+	case (MCHIP_MAX_LENGTH - 1):
+		/* verify byte is valid for current index */
+		if (0x80 & data) {
+			/* byte not valid */
+			mchip->data[0] = data;
+			mchip->index = 1;
+			break;
+		}
+
+		mchip->index = 0;
+		input_report_abs(dev, ABS_MT_TRACKING_ID, \
+		(mchip->data[0]&0x60) >> 5);
+		input_report_abs(dev, ABS_MT_POSITION_X, \
+		((mchip->data[2] & 0x1f) << 7) | (mchip->data[1] & 0x7f));
+		input_report_abs(dev, ABS_MT_POSITION_Y, \
+		((mchip->data[4] & 0x1f) << 7) | (mchip->data[3] & 0x7f));
+		input_report_abs(dev, ABS_MT_TOUCH_MAJOR, \
+		255*(0 != (mchip->data[0] & 7)));
+		input_mt_sync(dev);
+
+		/* touchscreen emulation for ID 0 */
+		if (0 == ((mchip->data[0]&0x60) >> 5)) {
+			input_report_abs(dev, ABS_X, \
+			((mchip->data[2]&0x1f) << 7)|(mchip->data[1]&0x7f));
+			input_report_abs(dev, ABS_Y, \
+			((mchip->data[4]&0x1f) << 7)|(mchip->data[3]&0x7f));
+			input_report_key(dev, BTN_TOUCH, \
+			0 != (mchip->data[0] & 7));
+		}
+
+		input_sync(dev);
+		break;
+	default:
+		/* verify byte is valid for current index */
+		if (0x80 & data) {
+			/* byte not valid */
+			mchip->data[0] = data;
+			mchip->index = 1;
+		}
+		break;
+	}
+}
+
+
+static irqreturn_t mchppcap_interrupt(struct serio *serio,
+		unsigned char data, unsigned int flags)
+{
+	struct mchip *mchip = serio_get_drvdata(serio);
+
+	mchppcap_process_data(mchip, data);
+
+	return IRQ_HANDLED;
+}
+
+static int mchppcap_setup(struct mchip *mchip)
+{
+	struct input_dev *dev = mchip->dev;
+
+	input_set_abs_params(dev, ABS_X, 0, 1023, 0, 0);
+	input_set_abs_params(dev, ABS_Y, 0, 1023, 0, 0);
+
+	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, 1023, 0, 0);
+	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, 1023, 0, 0);
+	input_set_abs_params(dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
+	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, 3, 0, 0);
+
+	return 0;
+}
+
+/*
+ * mchppcap_disconnect() is the opposite of mchppcap_connect()
+ */
+
+static void mchppcap_disconnect(struct serio *serio)
+{
+	struct mchip *mchip = serio_get_drvdata(serio);
+
+	input_get_device(mchip->dev);
+	input_unregister_device(mchip->dev);
+	serio_close(serio);
+	serio_set_drvdata(serio, NULL);
+	input_put_device(mchip->dev);
+	kfree(mchip);
+}
+
+/*
+ * mchppcap_connect() is the routine that is called when someone adds a
+ * new serio device that supports PCAP protocol and registers it as
+ * an input device.
+ */
+
+static int mchppcap_connect(struct serio *serio, struct serio_driver *drv)
+{
+	struct mchip *mchip;
+	struct input_dev *input_dev;
+	int err;
+
+	mchip = kzalloc(sizeof(struct mchip), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!mchip || !input_dev) {
+		err = -ENOMEM;
+		goto fail1;
+	}
+
+	mchip->serio = serio;
+	mchip->id = serio->id.id;
+	mchip->dev = input_dev;
+	snprintf(mchip->phys, sizeof(mchip->phys), "%s/input0", serio->phys);
+
+	input_dev->name = "Microchip Serial TouchScreen";
+	input_dev->phys = mchip->phys;
+	input_dev->id.bustype = BUS_RS232;
+	input_dev->id.vendor = SERIO_MCHPPCAP;
+	input_dev->id.product = mchip->id;
+	input_dev->id.version = 0x0100;
+	input_dev->dev.parent = &serio->dev;
+
+	set_bit(EV_SYN, input_dev->evbit);
+	set_bit(EV_KEY, input_dev->evbit);
+	set_bit(BTN_TOUCH, input_dev->keybit);
+	set_bit(BTN_2, input_dev->keybit);
+	set_bit(EV_ABS, input_dev->evbit);
+
+	serio_set_drvdata(serio, mchip);
+
+	err = serio_open(serio, drv);
+	if (err)
+		goto fail2;
+
+
+	mchppcap_setup(mchip);
+
+	err = input_register_device(mchip->dev);
+	if (err)
+		goto fail3;
+
+	return 0;
+
+fail3: serio_close(serio);
+fail2: serio_set_drvdata(serio, NULL);
+fail1: input_free_device(input_dev);
+	kfree(mchip);
+	return err;
+}
+
+/*
+ * The serio driver structure.
+ */
+
+static struct serio_device_id mchppcap_serio_ids[] = {
+	{
+		.type	= SERIO_RS232,
+		.proto	= SERIO_MCHPPCAP,
+		.id	= SERIO_ANY,
+		.extra	= SERIO_ANY,
+	},
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(serio, mchppcap_serio_ids);
+
+static struct serio_driver mchppcap_drv = {
+	.driver		= {
+		.name	= "mchip",
+	},
+	.description	= DRIVER_DESC,
+	.id_table	= mchppcap_serio_ids,
+	.interrupt	= mchppcap_interrupt,
+	.connect	= mchppcap_connect,
+	.disconnect	= mchppcap_disconnect,
+};
+
+/*
+ * The functions for inserting/removing us as a module.
+ */
+
+static int __init mchppcap_init(void)
+{
+	return serio_register_driver(&mchppcap_drv);
+}
+
+static void __exit mchppcap_exit(void)
+{
+	serio_unregister_driver(&mchppcap_drv);
+}
+
+module_init(mchppcap_init);
+module_exit(mchppcap_exit);
diff --git a/include/linux/serio.h b/include/linux/serio.h
index b555256..3a7b8a9 100644
--- a/include/linux/serio.h
+++ b/include/linux/serio.h
@@ -197,5 +197,6 @@ static inline void serio_continue_rx(struct serio *serio)
 #define SERIO_W8001	0x39
 #define SERIO_DYNAPRO	0x3a
 #define SERIO_HAMPSHIRE	0x3b
+#define SERIO_MCHPPCAP	0x3d
 
 #endif
-- 
1.7.1