Input: Add Synaptics NavPoint (PXA27x SSP/SPI) driver

This driver adds support for the Synaptics NavPoint touchpad connected
to a PXA27x SSP port in SPI slave mode. The device emulates a mouse;
a tap or tap-and-a-half drag gesture emulates the left mouse button.
For example, use the xf86-input-evdev driver for an X pointing device.

Signed-off-by: Paul Parsons <[e-mail]>
Tested-by: Philipp Zabel <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/mouse/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called synaptics_usb.
 
+config MOUSE_NAVPOINT_PXA27x
+	tristate "Synaptics NavPoint (PXA27x SSP/SPI)"
+	depends on PXA27x && PXA_SSP
+	help
+	  This driver adds support for the Synaptics NavPoint touchpad connected
+	  to a PXA27x SSP port in SPI slave mode. The device emulates a mouse;
+	  a tap or tap-and-a-half drag gesture emulates the left mouse button.
+	  For example, use the xf86-input-evdev driver for an X pointing device.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called navpoint.
+
 endif

drivers/input/mouse/Makefile

···
 obj-$(CONFIG_MOUSE_INPORT)		+= inport.o
 obj-$(CONFIG_MOUSE_LOGIBM)		+= logibm.o
 obj-$(CONFIG_MOUSE_MAPLE)		+= maplemouse.o
+obj-$(CONFIG_MOUSE_NAVPOINT_PXA27x)	+= navpoint.o
 obj-$(CONFIG_MOUSE_PC110PAD)		+= pc110pad.o
 obj-$(CONFIG_MOUSE_PS2)			+= psmouse.o
 obj-$(CONFIG_MOUSE_PXA930_TRKBALL)	+= pxa930_trkball.o

drivers/input/mouse/navpoint.c

···
+/*
+ * Synaptics NavPoint (PXA27x SSP/SPI) driver.
+ *
+ * Copyright (C) 2012 Paul Parsons <[e-mail]>
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/input.h>
+#include <linux/input/navpoint.h>
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/pxa2xx_ssp.h>
+#include <linux/slab.h>
+
+/*
+ * Synaptics Modular Embedded Protocol: Module Packet Format.
+ * Module header byte 2:0 = Length (# bytes that follow)
+ * Module header byte 4:3 = Control
+ * Module header byte 7:5 = Module Address
+ */
+#define HEADER_LENGTH(byte)	((byte) & 0x07)
+#define HEADER_CONTROL(byte)	(((byte) >> 3) & 0x03)
+#define HEADER_ADDRESS(byte)	((byte) >> 5)
+
+struct navpoint {
+	struct ssp_device	*ssp;
+	struct input_dev	*input;
+	struct device		*dev;
+	int			gpio;
+	int			index;
+	u8			data[1 + HEADER_LENGTH(0xff)];
+};
+
+/*
+ * Initialization values for SSCR0_x, SSCR1_x, SSSR_x.
+ */
+static const u32 sscr0 = 0
+	| SSCR0_TUM		/* TIM = 1; No TUR interrupts */
+	| SSCR0_RIM		/* RIM = 1; No ROR interrupts */
+	| SSCR0_SSE		/* SSE = 1; SSP enabled */
+	| SSCR0_Motorola	/* FRF = 0; Motorola SPI */
+	| SSCR0_DataSize(16)	/* DSS = 15; Data size = 16-bit */
+	;
+static const u32 sscr1 = 0
+	| SSCR1_SCFR		/* SCFR = 1; SSPSCLK only during transfers */
+	| SSCR1_SCLKDIR		/* SCLKDIR = 1; Slave mode */
+	| SSCR1_SFRMDIR		/* SFRMDIR = 1; Slave mode */
+	| SSCR1_RWOT		/* RWOT = 1; Receive without transmit mode */
+	| SSCR1_RxTresh(1)	/* RFT = 0; Receive FIFO threshold = 1 */
+	| SSCR1_SPH		/* SPH = 1; SSPSCLK inactive 0.5 + 1 cycles */
+	| SSCR1_RIE		/* RIE = 1; Receive FIFO interrupt enabled */
+	;
+static const u32 sssr = 0
+	| SSSR_BCE		/* BCE = 1; Clear BCE */
+	| SSSR_TUR		/* TUR = 1; Clear TUR */
+	| SSSR_EOC		/* EOC = 1; Clear EOC */
+	| SSSR_TINT		/* TINT = 1; Clear TINT */
+	| SSSR_PINT		/* PINT = 1; Clear PINT */
+	| SSSR_ROR		/* ROR = 1; Clear ROR */
+	;
+
+/*
+ * MEP Query $22: Touchpad Coordinate Range Query is not supported by
+ * the NavPoint module, so sampled values provide the default limits.
+ */
+#define NAVPOINT_X_MIN		1278
+#define NAVPOINT_X_MAX		5340
+#define NAVPOINT_Y_MIN		1572
+#define NAVPOINT_Y_MAX		4396
+#define NAVPOINT_PRESSURE_MIN	0
+#define NAVPOINT_PRESSURE_MAX	255
+
+static void navpoint_packet(struct navpoint *navpoint)
+{
+	int finger;
+	int gesture;
+	int x, y, z;
+
+	switch (navpoint->data[0]) {
+	case 0xff:	/* Garbage (packet?) between reset and Hello packet */
+	case 0x00:	/* Module 0, NULL packet */
+		break;
+
+	case 0x0e:	/* Module 0, Absolute packet */
+		finger = (navpoint->data[1] & 0x01);
+		gesture = (navpoint->data[1] & 0x02);
+		x = ((navpoint->data[2] & 0x1f) << 8) | navpoint->data[3];
+		y = ((navpoint->data[4] & 0x1f) << 8) | navpoint->data[5];
+		z = navpoint->data[6];
+		input_report_key(navpoint->input, BTN_TOUCH, finger);
+		input_report_abs(navpoint->input, ABS_X, x);
+		input_report_abs(navpoint->input, ABS_Y, y);
+		input_report_abs(navpoint->input, ABS_PRESSURE, z);
+		input_report_key(navpoint->input, BTN_TOOL_FINGER, finger);
+		input_report_key(navpoint->input, BTN_LEFT, gesture);
+		input_sync(navpoint->input);
+		break;
+
+	case 0x19:	/* Module 0, Hello packet */
+		if ((navpoint->data[1] & 0xf0) == 0x10)
+			break;
+		/* FALLTHROUGH */
+	default:
+		dev_warn(navpoint->dev,
+			 "spurious packet: data=0x%02x,0x%02x,...\n",
+			 navpoint->data[0], navpoint->data[1]);
+		break;
+	}
+}
+
+static irqreturn_t navpoint_irq(int irq, void *dev_id)
+{
+	struct navpoint *navpoint = dev_id;
+	struct ssp_device *ssp = navpoint->ssp;
+	irqreturn_t ret = IRQ_NONE;
+	u32 status;
+
+	status = pxa_ssp_read_reg(ssp, SSSR);
+	if (status & sssr) {
+		dev_warn(navpoint->dev,
+			 "unexpected interrupt: status=0x%08x\n", status);
+		pxa_ssp_write_reg(ssp, SSSR, (status & sssr));
+		ret = IRQ_HANDLED;
+	}
+
+	while (status & SSSR_RNE) {
+		u32 data;
+
+		data = pxa_ssp_read_reg(ssp, SSDR);
+		navpoint->data[navpoint->index + 0] = (data >> 8);
+		navpoint->data[navpoint->index + 1] = data;
+		navpoint->index += 2;
+		if (HEADER_LENGTH(navpoint->data[0]) < navpoint->index) {
+			navpoint_packet(navpoint);
+			navpoint->index = 0;
+		}
+		status = pxa_ssp_read_reg(ssp, SSSR);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static void navpoint_up(struct navpoint *navpoint)
+{
+	struct ssp_device *ssp = navpoint->ssp;
+	int timeout;
+
+	clk_prepare_enable(ssp->clk);
+
+	pxa_ssp_write_reg(ssp, SSCR1, sscr1);
+	pxa_ssp_write_reg(ssp, SSSR, sssr);
+	pxa_ssp_write_reg(ssp, SSTO, 0);
+	pxa_ssp_write_reg(ssp, SSCR0, sscr0);	/* SSCR0_SSE written last */
+
+	/* Wait until SSP port is ready for slave clock operations */
+	for (timeout = 100; timeout != 0; --timeout) {
+		if (!(pxa_ssp_read_reg(ssp, SSSR) & SSSR_CSS))
+			break;
+		msleep(1);
+	}
+
+	if (timeout == 0)
+		dev_err(navpoint->dev,
+			"timeout waiting for SSSR[CSS] to clear\n");
+
+	if (gpio_is_valid(navpoint->gpio))
+		gpio_set_value(navpoint->gpio, 1);
+}
+
+static void navpoint_down(struct navpoint *navpoint)
+{
+	struct ssp_device *ssp = navpoint->ssp;
+
+	if (gpio_is_valid(navpoint->gpio))
+		gpio_set_value(navpoint->gpio, 0);
+
+	pxa_ssp_write_reg(ssp, SSCR0, 0);
+
+	clk_disable_unprepare(ssp->clk);
+}
+
+static int navpoint_open(struct input_dev *input)
+{
+	struct navpoint *navpoint = input_get_drvdata(input);
+
+	navpoint_up(navpoint);
+
+	return 0;
+}
+
+static void navpoint_close(struct input_dev *input)
+{
+	struct navpoint *navpoint = input_get_drvdata(input);
+
+	navpoint_down(navpoint);
+}
+
+static int __devinit navpoint_probe(struct platform_device *pdev)
+{
+	const struct navpoint_platform_data *pdata =
+					dev_get_platdata(&pdev->dev);
+	struct ssp_device *ssp;
+	struct input_dev *input;
+	struct navpoint *navpoint;
+	int error;
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "no platform data\n");
+		return -EINVAL;
+	}
+
+	if (gpio_is_valid(pdata->gpio)) {
+		error = gpio_request_one(pdata->gpio, GPIOF_OUT_INIT_LOW,
+					 "SYNAPTICS_ON");
+		if (error)
+			return error;
+	}
+
+	ssp = pxa_ssp_request(pdata->port, pdev->name);
+	if (!ssp) {
+		error = -ENODEV;
+		goto err_free_gpio;
+	}
+
+	/* HaRET does not disable devices before jumping into Linux */
+	if (pxa_ssp_read_reg(ssp, SSCR0) & SSCR0_SSE) {
+		pxa_ssp_write_reg(ssp, SSCR0, 0);
+		dev_warn(&pdev->dev, "ssp%d already enabled\n", pdata->port);
+	}
+
+	navpoint = kzalloc(sizeof(*navpoint), GFP_KERNEL);
+	input = input_allocate_device();
+	if (!navpoint || !input) {
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	navpoint->ssp = ssp;
+	navpoint->input = input;
+	navpoint->dev = &pdev->dev;
+	navpoint->gpio = pdata->gpio;
+
+	input->name = pdev->name;
+	input->dev.parent = &pdev->dev;
+
+	__set_bit(EV_KEY, input->evbit);
+	__set_bit(EV_ABS, input->evbit);
+	__set_bit(BTN_LEFT, input->keybit);
+	__set_bit(BTN_TOUCH, input->keybit);
+	__set_bit(BTN_TOOL_FINGER, input->keybit);
+
+	input_set_abs_params(input, ABS_X,
+			     NAVPOINT_X_MIN, NAVPOINT_X_MAX, 0, 0);
+	input_set_abs_params(input, ABS_Y,
+			     NAVPOINT_Y_MIN, NAVPOINT_Y_MAX, 0, 0);
+	input_set_abs_params(input, ABS_PRESSURE,
+			     NAVPOINT_PRESSURE_MIN, NAVPOINT_PRESSURE_MAX,
+			     0, 0);
+
+	input->open = navpoint_open;
+	input->close = navpoint_close;
+
+	input_set_drvdata(input, navpoint);
+
+	error = request_irq(ssp->irq, navpoint_irq, 0, pdev->name, navpoint);
+	if (error)
+		goto err_free_mem;
+
+	error = input_register_device(input);
+	if (error)
+		goto err_free_irq;
+
+	platform_set_drvdata(pdev, navpoint);
+	dev_dbg(&pdev->dev, "ssp%d, irq %d\n", pdata->port, ssp->irq);
+
+	return 0;
+
+err_free_irq:
+	free_irq(ssp->irq, &pdev->dev);
+err_free_mem:
+	input_free_device(input);
+	kfree(navpoint);
+	pxa_ssp_free(ssp);
+err_free_gpio:
+	if (gpio_is_valid(pdata->gpio))
+		gpio_free(pdata->gpio);
+
+	return error;
+}
+
+static int __devexit navpoint_remove(struct platform_device *pdev)
+{
+	const struct navpoint_platform_data *pdata =
+					dev_get_platdata(&pdev->dev);
+	struct navpoint *navpoint = platform_get_drvdata(pdev);
+	struct ssp_device *ssp = navpoint->ssp;
+
+	free_irq(ssp->irq, navpoint);
+
+	input_unregister_device(navpoint->input);
+	kfree(navpoint);
+
+	pxa_ssp_free(ssp);
+
+	if (gpio_is_valid(pdata->gpio))
+		gpio_free(pdata->gpio);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int navpoint_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct navpoint *navpoint = platform_get_drvdata(pdev);
+	struct input_dev *input = navpoint->input;
+
+	mutex_lock(&input->mutex);
+	if (input->users)
+		navpoint_down(navpoint);
+	mutex_unlock(&input->mutex);
+
+	return 0;
+}
+
+static int navpoint_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct navpoint *navpoint = platform_get_drvdata(pdev);
+	struct input_dev *input = navpoint->input;
+
+	mutex_lock(&input->mutex);
+	if (input->users)
+		navpoint_up(navpoint);
+	mutex_unlock(&input->mutex);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(navpoint_pm_ops, navpoint_suspend, navpoint_resume);
+
+static struct platform_driver navpoint_driver = {
+	.probe		= navpoint_probe,
+	.remove		= __devexit_p(navpoint_remove),
+	.driver = {
+		.name	= "navpoint",
+		.owner	= THIS_MODULE,
+		.pm	= &navpoint_pm_ops,
+	},
+};
+
+module_platform_driver(navpoint_driver);
+
+MODULE_AUTHOR("Paul Parsons <[e-mail]>");
+MODULE_DESCRIPTION("Synaptics NavPoint (PXA27x SSP/SPI) driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:navpoint");

include/linux/input/navpoint.h

···
+/*
+ *  Copyright (C) 2012 Paul Parsons <[e-mail]>
+ *
+ *  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.
+ */
+
+struct navpoint_platform_data {
+	int		port;		/* PXA SSP port for pxa_ssp_request() */
+	int		gpio;		/* GPIO for power on/off */
+};