rpi-ft5406: Add touchscreen driver for pi LCD display

Author: ghollingworth

drivers/input/touchscreen/Kconfig

@@ -557,6 +557,13 @@ config TOUCHSCREEN_EDT_FT5X06
 	  To compile this driver as a module, choose M here: the
 	  module will be called edt-ft5x06.
 
+config TOUCHSCREEN_RPI_FT5406
+	tristate "Raspberry Pi FT5406 driver"
+	depends on ARCH_BCM2708 || ARCH_BCM2709
+	help
+	  Say Y here to enable the Raspberry Pi memory based FT5406 device
+
+
 config TOUCHSCREEN_MIGOR
 	tristate "Renesas MIGO-R touchscreen"
 	depends on SH_MIGOR && I2C

drivers/input/touchscreen/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_TOUCHSCREEN_DA9034)	+= da9034-ts.o
 obj-$(CONFIG_TOUCHSCREEN_DA9052)	+= da9052_tsi.o
 obj-$(CONFIG_TOUCHSCREEN_DYNAPRO)	+= dynapro.o
 obj-$(CONFIG_TOUCHSCREEN_EDT_FT5X06)	+= edt-ft5x06.o
+obj-$(CONFIG_TOUCHSCREEN_RPI_FT5406)	+= rpi-ft5406.o
 obj-$(CONFIG_TOUCHSCREEN_HAMPSHIRE)	+= hampshire.o
 obj-$(CONFIG_TOUCHSCREEN_GUNZE)		+= gunze.o
 obj-$(CONFIG_TOUCHSCREEN_EETI)		+= eeti_ts.o

drivers/input/touchscreen/rpi-ft5406.c

@@ -0,0 +1,258 @@
+/*
+ * Driver for memory based ft5406 touchscreen
+ *
+ * Copyright (C) 2015 Raspberry Pi
+ *
+ *
+ * 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.
+ */
+
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/input/mt.h>
+#include <linux/kthread.h>
+#include <linux/platform_device.h>
+#include <asm/io.h>
+#include <linux/platform_data/mailbox-bcm2708.h>
+
+#define MAXIMUM_SUPPORTED_POINTS 10
+struct ft5406_regs {
+	uint8_t device_mode;
+	uint8_t gesture_id;
+	uint8_t num_points;
+	struct ft5406_touch {
+		uint8_t xh;
+		uint8_t xl;
+		uint8_t yh;
+		uint8_t yl;
+		uint8_t res1;
+		uint8_t res2;
+	} point[MAXIMUM_SUPPORTED_POINTS];
+};
+
+#define SCREEN_WIDTH  800
+#define SCREEN_HEIGHT 480
+
+struct ft5406 {
+	struct platform_device * pdev;
+	struct input_dev       * input_dev;
+	void __iomem           * ts_base;
+	struct ft5406_regs     * regs;
+	struct task_struct     * thread;
+};
+
+
+/* tag part of the message */
+struct vc_msg_tag {
+	uint32_t tag_id;		/* the message id */
+	uint32_t buffer_size;	/* size of the buffer (which in this case is always 8 bytes) */
+	uint32_t data_size;		/* amount of data being sent or received */
+	uint32_t val;           /* data buffer */
+};
+
+/* message structure to be sent to videocore */
+struct vc_msg {
+	uint32_t msg_size;		/* simply, sizeof(struct vc_msg) */
+	uint32_t request_code;	/* holds various information like the success and number of bytes returned (refer to mailboxes wiki) */
+	struct vc_msg_tag tag;	/* the tag structure above to make */
+	uint32_t end_tag;		/* an end identifier, should be set to NULL */
+};
+
+/* Thread to poll for touchscreen events
+ * 
+ * This thread polls the memory based register copy of the ft5406 registers
+ * using the number of points register to know whether the copy has been
+ * updated (we write 99 to the memory copy, the GPU will write between 
+ * 0 - 10 points)
+ */
+static int ft5406_thread(void *arg)
+{
+	struct ft5406 *ts = (struct ft5406 *) arg;
+	struct ft5406_regs regs;
+	int known_ids = 0;
+	
+	while(!kthread_should_stop())
+	{
+		// 60fps polling
+		msleep(17);
+		memcpy_fromio(&regs, ts->regs, sizeof(*ts->regs));
+		writel(99, &ts->regs->num_points);
+		// Do not output if theres no new information (num_points is 99)
+		// or we have no touch points and don't need to release any
+		if(!(regs.num_points == 99 || (regs.num_points == 0 && known_ids == 0)))
+		{
+			int i;
+			int modified_ids = 0, released_ids;
+			for(i = 0; i < regs.num_points; i++)
+			{
+				int x = (((int) regs.point[i].xh & 0xf) << 8) + regs.point[i].xl;
+				int y = (((int) regs.point[i].yh & 0xf) << 8) + regs.point[i].yl;
+				int touchid = (regs.point[i].yh >> 4) & 0xf;
+				
+				modified_ids |= 1 << touchid;
+
+				if(!((1 << touchid) & known_ids))
+					dev_dbg(&ts->pdev->dev, "x = %d, y = %d, touchid = %d\n", x, y, touchid);
+				
+				input_mt_slot(ts->input_dev, touchid);
+				input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, 1);
+
+				input_report_abs(ts->input_dev, ABS_MT_POSITION_X, x);
+				input_report_abs(ts->input_dev, ABS_MT_POSITION_Y, y);
+
+			}
+
+			released_ids = known_ids & ~modified_ids;
+			for(i = 0; released_ids && i < MAXIMUM_SUPPORTED_POINTS; i++)
+			{
+				if(released_ids & (1<<i))
+				{
+					dev_dbg(&ts->pdev->dev, "Released %d, known = %x modified = %x\n", i, known_ids, modified_ids);
+					input_mt_slot(ts->input_dev, i);
+					input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, 0);
+					modified_ids &= ~(1 << i);
+				}
+			}
+			known_ids = modified_ids;
+			
+			input_mt_report_pointer_emulation(ts->input_dev, true);
+			input_sync(ts->input_dev);
+		}
+			
+	}
+	
+	return 0;
+}
+
+static int ft5406_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct input_dev * input_dev = input_allocate_device();
+	struct vc_msg request;
+	struct ft5406 * ts;
+	
+	dev_info(&pdev->dev, "Probing device\n");
+	
+	ts = kzalloc(sizeof(struct ft5406), GFP_KERNEL);
+
+	if (!ts || !input_dev) {
+		ret = -ENOMEM;
+		dev_err(&pdev->dev, "Failed to allocate memory\n");
+		return ret;
+	}
+	ts->input_dev = input_dev;
+	platform_set_drvdata(pdev, ts);
+	ts->pdev = pdev;
+	
+	input_dev->name = "FT5406 memory based driver";
+	
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(EV_SYN, input_dev->evbit);
+	__set_bit(EV_ABS, input_dev->evbit);
+
+	input_set_abs_params(input_dev, ABS_MT_POSITION_X, 0,
+			     SCREEN_WIDTH, 0, 0);
+	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, 0,
+			     SCREEN_HEIGHT, 0, 0);
+
+	input_mt_init_slots(input_dev, MAXIMUM_SUPPORTED_POINTS, INPUT_MT_DIRECT);
+
+	input_set_drvdata(input_dev, ts);
+	
+	ret = input_register_device(input_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "could not register input device, %d\n",
+			ret);
+		return ret;
+	}
+	
+	memset(&request, 0, sizeof request);
+
+	request.msg_size = sizeof request;
+	request.request_code = VCMSG_PROCESS_REQUEST;
+	request.tag.tag_id = VCMSG_GET_TOUCHBUF;
+	request.tag.buffer_size = 4;
+	request.tag.data_size = 4;
+	
+	bcm_mailbox_property(&request, sizeof(request));
+	
+	if(request.request_code == VCMSG_REQUEST_SUCCESSFUL)
+	{
+		dev_dbg(&pdev->dev, "Got TS buffer 0x%x\n", request.tag.val);
+	}
+	else
+	{
+		input_unregister_device(input_dev);
+		kzfree(ts);
+		return -1;
+	}
+	
+	// mmap the physical memory
+	request.tag.val &= ~0xc0000000;
+	ts->ts_base = ioremap(request.tag.val, sizeof(*ts->regs));
+	if(ts->ts_base == NULL)
+	{
+		dev_err(&pdev->dev, "Failed to map physical address\n");
+		input_unregister_device(input_dev);
+		kzfree(ts);
+		return -1;	
+	}
+	
+	ts->regs = (struct ft5406_regs *) ts->ts_base;
+
+	// create thread to poll the touch events
+	ts->thread = kthread_run(ft5406_thread, ts, "ft5406");
+	if(ts->thread == NULL)
+	{
+		dev_err(&pdev->dev, "Failed to create kernel thread");
+		iounmap(ts->ts_base);
+		input_unregister_device(input_dev);
+		kzfree(ts);
+	}
+
+	return 0;
+}
+
+static int ft5406_remove(struct platform_device *pdev)
+{
+	struct ft5406 *ts = (struct ft5406 *) platform_get_drvdata(pdev);
+	
+	dev_info(&pdev->dev, "Removing rpi-ft5406\n");
+	
+	kthread_stop(ts->thread);
+	iounmap(ts->ts_base);
+	input_unregister_device(ts->input_dev);
+	kzfree(ts);
+	
+	return 0;
+}
+
+static const struct of_device_id ft5406_match[] = {
+	{ .compatible = "rpi,rpi-ft5406", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ft5406_match);
+
+static struct platform_driver ft5406_driver = {
+	.driver = {
+		.name   = "rpi-ft5406",
+		.owner  = THIS_MODULE,
+		.of_match_table = ft5406_match,
+	},
+	.probe          = ft5406_probe,
+	.remove         = ft5406_remove,
+};
+
+module_platform_driver(ft5406_driver);
+
+MODULE_AUTHOR("Gordon Hollingworth");
+MODULE_DESCRIPTION("Touchscreen driver for memory based FT5406");
+MODULE_LICENSE("GPL");

include/linux/platform_data/mailbox-bcm2708.h

@@ -115,6 +115,7 @@ enum {
 	VCMSG_SET_TRANSFORM              = 0x0004800d,
 	VCMSG_TST_VSYNC                  = 0x0004400e,
 	VCMSG_SET_VSYNC                  = 0x0004800e,
+	VCMSG_GET_TOUCHBUF               = 0x0004000f,
 	VCMSG_SET_CURSOR_INFO            = 0x00008010,
 	VCMSG_SET_CURSOR_STATE           = 0x00008011,
 };