Input: wm831x - add driver for Wolfson WM831x PMIC touchscreen controllers

Some of the WM831x series of PMICs from Wolfson Microelectronics include
a resistive touchscreen controller. Implement support for these controllers
within the input API.

Platform data is supported to allow configuration of system parameters such
as selection between four and five wire touchscreens and for specification
of optional direct to CPU IRQs for sample availability and for pen down.
Use of this feature for at least the data IRQ is strongly recommended.

Thanks to Julien Boibessot for extensive testing and detailed feedback.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Tested-by: Julien Boibessot <julien.boibessot@armadeus.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/touchscreen/Kconfig

@@ -423,6 +423,16 @@ config TOUCHSCREEN_UCB1400
 	  To compile this driver as a module, choose M here: the
 	  module will be called ucb1400_ts.
 
+config TOUCHSCREEN_WM831X
+	tristate "Support for WM831x touchscreen controllers"
+	depends on MFD_WM831X
+	help
+	  This enables support for the touchscreen controller on the WM831x
+	  series of PMICs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called wm831x-ts.
+
 config TOUCHSCREEN_WM97XX
 	tristate "Support for WM97xx AC97 touchscreen controllers"
 	depends on AC97_BUS

drivers/input/touchscreen/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)	+= touchwin.o
 obj-$(CONFIG_TOUCHSCREEN_TSC2007)	+= tsc2007.o
 obj-$(CONFIG_TOUCHSCREEN_UCB1400)	+= ucb1400_ts.o
 obj-$(CONFIG_TOUCHSCREEN_WACOM_W8001)	+= wacom_w8001.o
+obj-$(CONFIG_TOUCHSCREEN_WM831X)	+= wm831x-ts.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX)	+= wm97xx-ts.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9705)	+= wm9705.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712)	+= wm9712.o

drivers/input/touchscreen/wm831x-ts.c

+/*
+ * Touchscreen driver for WM831x PMICs
+ *
+ * Copyright 2011 Wolfson Microelectronics plc.
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ * 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;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/pm.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mfd/wm831x/core.h>
+#include <linux/mfd/wm831x/irq.h>
+#include <linux/mfd/wm831x/pdata.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+/*
+ * R16424 (0x4028) - Touch Control 1
+ */
+#define WM831X_TCH_ENA                          0x8000  /* TCH_ENA */
+#define WM831X_TCH_CVT_ENA                      0x4000  /* TCH_CVT_ENA */
+#define WM831X_TCH_SLPENA                       0x1000  /* TCH_SLPENA */
+#define WM831X_TCH_Z_ENA                        0x0400  /* TCH_Z_ENA */
+#define WM831X_TCH_Y_ENA                        0x0200  /* TCH_Y_ENA */
+#define WM831X_TCH_X_ENA                        0x0100  /* TCH_X_ENA */
+#define WM831X_TCH_DELAY_MASK                   0x00E0  /* TCH_DELAY - [7:5] */
+#define WM831X_TCH_DELAY_SHIFT                       5  /* TCH_DELAY - [7:5] */
+#define WM831X_TCH_DELAY_WIDTH                       3  /* TCH_DELAY - [7:5] */
+#define WM831X_TCH_RATE_MASK                    0x001F  /* TCH_RATE - [4:0] */
+#define WM831X_TCH_RATE_SHIFT                        0  /* TCH_RATE - [4:0] */
+#define WM831X_TCH_RATE_WIDTH                        5  /* TCH_RATE - [4:0] */
+
+/*
+ * R16425 (0x4029) - Touch Control 2
+ */
+#define WM831X_TCH_PD_WK                        0x2000  /* TCH_PD_WK */
+#define WM831X_TCH_5WIRE                        0x1000  /* TCH_5WIRE */
+#define WM831X_TCH_PDONLY                       0x0800  /* TCH_PDONLY */
+#define WM831X_TCH_ISEL                         0x0100  /* TCH_ISEL */
+#define WM831X_TCH_RPU_MASK                     0x000F  /* TCH_RPU - [3:0] */
+#define WM831X_TCH_RPU_SHIFT                         0  /* TCH_RPU - [3:0] */
+#define WM831X_TCH_RPU_WIDTH                         4  /* TCH_RPU - [3:0] */
+
+/*
+ * R16426-8 (0x402A-C) - Touch Data X/Y/X
+ */
+#define WM831X_TCH_PD                           0x8000  /* TCH_PD1 */
+#define WM831X_TCH_DATA_MASK                    0x0FFF  /* TCH_DATA - [11:0] */
+#define WM831X_TCH_DATA_SHIFT                        0  /* TCH_DATA - [11:0] */
+#define WM831X_TCH_DATA_WIDTH                       12  /* TCH_DATA - [11:0] */
+
+struct wm831x_ts {
+	struct input_dev *input_dev;
+	struct wm831x *wm831x;
+	unsigned int data_irq;
+	unsigned int pd_irq;
+	bool pressure;
+	bool pen_down;
+};
+
+static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data)
+{
+	struct wm831x_ts *wm831x_ts = irq_data;
+	struct wm831x *wm831x = wm831x_ts->wm831x;
+	static int data_types[] = { ABS_X, ABS_Y, ABS_PRESSURE };
+	u16 data[3];
+	int count = wm831x_ts->pressure ? 3 : 2;
+	int i, ret;
+
+	wm831x_set_bits(wm831x, WM831X_INTERRUPT_STATUS_1,
+			WM831X_TCHDATA_EINT, WM831X_TCHDATA_EINT);
+
+	ret = wm831x_bulk_read(wm831x, WM831X_TOUCH_DATA_X, count,
+			       data);
+	if (ret != 0) {
+		dev_err(wm831x->dev, "Failed to read touch data: %d\n",
+			ret);
+		return IRQ_NONE;
+	}
+
+	/*
+	 * We get a pen down reading on every reading, report pen up if any
+	 * individual reading does so.
+	 */
+	wm831x_ts->pen_down = true;
+	for (i = 0; i < count; i++) {
+		if (!(data[i] & WM831X_TCH_PD)) {
+			wm831x_ts->pen_down = false;
+			continue;
+		}
+		input_report_abs(wm831x_ts->input_dev, data_types[i],
+				 data[i] & WM831X_TCH_DATA_MASK);
+	}
+
+	if (!wm831x_ts->pen_down) {
+		disable_irq_nosync(wm831x_ts->data_irq);
+
+		/* Don't need data any more */
+		wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1,
+				WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA |
+				WM831X_TCH_Z_ENA, 0);
+
+		/* Flush any final samples that arrived while reading */
+		wm831x_set_bits(wm831x, WM831X_INTERRUPT_STATUS_1,
+				WM831X_TCHDATA_EINT, WM831X_TCHDATA_EINT);
+
+		wm831x_bulk_read(wm831x, WM831X_TOUCH_DATA_X, count, data);
+
+		if (wm831x_ts->pressure)
+			input_report_abs(wm831x_ts->input_dev,
+					 ABS_PRESSURE, 0);
+
+		input_report_key(wm831x_ts->input_dev, BTN_TOUCH, 0);
+	}
+
+	input_sync(wm831x_ts->input_dev);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t wm831x_ts_pen_down_irq(int irq, void *irq_data)
+{
+	struct wm831x_ts *wm831x_ts = irq_data;
+	struct wm831x *wm831x = wm831x_ts->wm831x;
+	int ena;
+
+	/* Start collecting data */
+	ena = wm831x_ts->pressure ? WM831X_TCH_Z_ENA : 0;
+
+	wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1,
+			WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA | WM831X_TCH_Z_ENA,
+			WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA | ena);
+
+	input_report_key(wm831x_ts->input_dev, BTN_TOUCH, 1);
+	input_sync(wm831x_ts->input_dev);
+
+	wm831x_set_bits(wm831x, WM831X_INTERRUPT_STATUS_1,
+			WM831X_TCHPD_EINT, WM831X_TCHPD_EINT);
+
+	wm831x_ts->pen_down = true;
+	enable_irq(wm831x_ts->data_irq);
+
+	return IRQ_HANDLED;
+}
+
+static int wm831x_ts_input_open(struct input_dev *idev)
+{
+	struct wm831x_ts *wm831x_ts = input_get_drvdata(idev);
+	struct wm831x *wm831x = wm831x_ts->wm831x;
+
+	wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1,
+			WM831X_TCH_ENA, WM831X_TCH_ENA);
+
+	wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1,
+			WM831X_TCH_CVT_ENA, WM831X_TCH_CVT_ENA);
+
+	return 0;
+}
+
+static void wm831x_ts_input_close(struct input_dev *idev)
+{
+	struct wm831x_ts *wm831x_ts = input_get_drvdata(idev);
+	struct wm831x *wm831x = wm831x_ts->wm831x;
+
+	wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1,
+			WM831X_TCH_ENA | WM831X_TCH_CVT_ENA |
+			WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA |
+			WM831X_TCH_Z_ENA, 0);
+
+	if (wm831x_ts->pen_down)
+		disable_irq(wm831x_ts->data_irq);
+}
+
+static __devinit int wm831x_ts_probe(struct platform_device *pdev)
+{
+	struct wm831x_ts *wm831x_ts;
+	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
+	struct wm831x_pdata *core_pdata = dev_get_platdata(pdev->dev.parent);
+	struct wm831x_touch_pdata *pdata =
+			core_pdata ? core_pdata->touch : NULL;
+	struct input_dev *input_dev;
+	int error;
+
+	wm831x_ts = kzalloc(sizeof(struct wm831x_ts), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!wm831x_ts || !input_dev) {
+		error = -ENOMEM;
+		goto err_alloc;
+	}
+
+	wm831x_ts->wm831x = wm831x;
+	wm831x_ts->input_dev = input_dev;
+
+	/*
+	 * If we have a direct IRQ use it, otherwise use the interrupt
+	 * from the WM831x IRQ controller.
+	 */
+	if (pdata && pdata->data_irq)
+		wm831x_ts->data_irq = pdata->data_irq;
+	else
+		wm831x_ts->data_irq = platform_get_irq_byname(pdev, "TCHDATA");
+
+	if (pdata && pdata->pd_irq)
+		wm831x_ts->pd_irq = pdata->pd_irq;
+	else
+		wm831x_ts->pd_irq = platform_get_irq_byname(pdev, "TCHPD");
+
+	wm831x_ts->pressure = pdata && pdata->pressure;
+
+	/* Five wire touchscreens can't report pressure */
+	if (pdata && pdata->fivewire) {
+		wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_2,
+				WM831X_TCH_5WIRE, WM831X_TCH_5WIRE);
+
+		/* Pressure measurements are not possible for five wire mode */
+		WARN_ON(pdata->pressure && pdata->fivewire);
+		wm831x_ts->pressure = false;
+	} else {
+		wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_2,
+				WM831X_TCH_5WIRE, 0);
+	}
+
+	if (pdata) {
+		switch (pdata->isel) {
+		default:
+			dev_err(&pdev->dev, "Unsupported ISEL setting: %d\n",
+				pdata->isel);
+			/* Fall through */
+		case 200:
+		case 0:
+			wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_2,
+					WM831X_TCH_ISEL, 0);
+			break;
+		case 400:
+			wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_2,
+					WM831X_TCH_ISEL, WM831X_TCH_ISEL);
+			break;
+		}
+	}
+
+	wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_2,
+			WM831X_TCH_PDONLY, 0);
+
+	/* Default to 96 samples/sec */
+	wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1,
+			WM831X_TCH_RATE_MASK, 6);
+
+	error = request_threaded_irq(wm831x_ts->data_irq,
+				     NULL, wm831x_ts_data_irq,
+				     IRQF_ONESHOT,
+				     "Touchscreen data", wm831x_ts);
+	if (error) {
+		dev_err(&pdev->dev, "Failed to request data IRQ %d: %d\n",
+			wm831x_ts->data_irq, error);
+		goto err_alloc;
+	}
+	disable_irq(wm831x_ts->data_irq);
+
+	error = request_threaded_irq(wm831x_ts->pd_irq,
+				     NULL, wm831x_ts_pen_down_irq,
+				     IRQF_ONESHOT,
+				     "Touchscreen pen down", wm831x_ts);
+	if (error) {
+		dev_err(&pdev->dev, "Failed to request pen down IRQ %d: %d\n",
+			wm831x_ts->pd_irq, error);
+		goto err_data_irq;
+	}
+
+	/* set up touch configuration */
+	input_dev->name = "WM831x touchscreen";
+	input_dev->phys = "wm831x";
+	input_dev->open = wm831x_ts_input_open;
+	input_dev->close = wm831x_ts_input_close;
+
+	__set_bit(EV_ABS, input_dev->evbit);
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(BTN_TOUCH, input_dev->keybit);
+
+	input_set_abs_params(input_dev, ABS_X, 0, 4095, 5, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, 4095, 5, 0);
+	if (wm831x_ts->pressure)
+		input_set_abs_params(input_dev, ABS_PRESSURE, 0, 4095, 5, 0);
+
+	input_set_drvdata(input_dev, wm831x_ts);
+	input_dev->dev.parent = &pdev->dev;
+
+	error = input_register_device(input_dev);
+	if (error)
+		goto err_pd_irq;
+
+	platform_set_drvdata(pdev, wm831x_ts);
+	return 0;
+
+err_pd_irq:
+	free_irq(wm831x_ts->pd_irq, wm831x_ts);
+err_data_irq:
+	free_irq(wm831x_ts->data_irq, wm831x_ts);
+err_alloc:
+	input_free_device(input_dev);
+	kfree(wm831x_ts);
+
+	return error;
+}
+
+static __devexit int wm831x_ts_remove(struct platform_device *pdev)
+{
+	struct wm831x_ts *wm831x_ts = platform_get_drvdata(pdev);
+
+	free_irq(wm831x_ts->pd_irq, wm831x_ts);
+	free_irq(wm831x_ts->data_irq, wm831x_ts);
+	input_unregister_device(wm831x_ts->input_dev);
+	kfree(wm831x_ts);
+
+	platform_set_drvdata(pdev, NULL);
+	return 0;
+}
+
+static struct platform_driver wm831x_ts_driver = {
+	.driver = {
+		.name = "wm831x-touch",
+		.owner = THIS_MODULE,
+	},
+	.probe = wm831x_ts_probe,
+	.remove = __devexit_p(wm831x_ts_remove),
+};
+
+static int __init wm831x_ts_init(void)
+{
+	return platform_driver_register(&wm831x_ts_driver);
+}
+module_init(wm831x_ts_init);
+
+static void __exit wm831x_ts_exit(void)
+{
+	platform_driver_unregister(&wm831x_ts_driver);
+}
+module_exit(wm831x_ts_exit);
+
+/* Module information */
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
+MODULE_DESCRIPTION("WM831x PMIC touchscreen driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm831x-touch");

include/linux/mfd/wm831x/pdata.h

@@ -80,7 +80,8 @@ struct wm831x_touch_pdata {
 	int isel;              /** Current for pen down (uA) */
 	int rpu;               /** Pen down sensitivity resistor divider */
 	int pressure;          /** Report pressure (boolean) */
-	int data_irq;          /** Touch data ready IRQ */
+	unsigned int data_irq; /** Touch data ready IRQ */
+	unsigned int pd_irq;   /** Touch pendown detect IRQ */
 };
 
 enum wm831x_watchdog_action {