input: Touchscreen driver for TPS6507x

Add touch screen input driver for TPS6507x family of multi-function
chips. Uses the TPS6507x MFD driver. No interrupt support due to
testing limitations of current hardware.

Signed-off-by: Todd Fischer <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/input/touchscreen/Kconfig

···
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called pcap_ts.
+
+config TOUCHSCREEN_TPS6507X
+	tristate "TPS6507x based touchscreens"
+	depends on I2C
+	help
+	  Say Y here if you have a TPS6507x based touchscreen
+	  controller.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called tps6507x_ts.
+
 endif

drivers/input/touchscreen/Makefile

···
 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

drivers/input/touchscreen/tps6507x-ts.c

···
+/*
+ * drivers/input/touchscreen/tps6507x_ts.c
+ *
+ * Touchscreen driver for the tps6507x chip.
+ *
+ * Copyright (c) 2009 RidgeRun ([e-mail])
+ *
+ * Credits:
+ *
+ *    Using code from tsc2007, MtekVision Co., Ltd.
+ *
+ * For licencing details see kernel-base/COPYING
+ *
+ * TPS65070, TPS65073, TPS650731, and TPS650732 support
+ * 10 bit touch screen interface.
+ */
+
+#include <linux/module.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/tps6507x.h>
+#include <linux/input/tps6507x-ts.h>
+#include <linux/delay.h>
+
+#define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
+#define TPS_DEFAULT_MIN_PRESSURE 0x30
+#define MAX_10BIT ((1 << 10) - 1)
+
+#define	TPS6507X_ADCONFIG_CONVERT_TS (TPS6507X_ADCONFIG_AD_ENABLE | \
+					 TPS6507X_ADCONFIG_START_CONVERSION | \
+					 TPS6507X_ADCONFIG_INPUT_REAL_TSC)
+#define	TPS6507X_ADCONFIG_POWER_DOWN_TS (TPS6507X_ADCONFIG_INPUT_REAL_TSC)
+
+struct ts_event {
+	u16	x;
+	u16	y;
+	u16	pressure;
+};
+
+struct tps6507x_ts {
+	struct input_dev	*input_dev;
+	struct device		*dev;
+	char			phys[32];
+	struct workqueue_struct *wq;
+	struct delayed_work	work;
+	unsigned		polling;	/* polling is active */
+	struct ts_event		tc;
+	struct tps6507x_dev	*mfd;
+	u16			model;
+	unsigned		pendown;
+	int			irq;
+	void			(*clear_penirq)(void);
+	unsigned long		poll_period;	/* ms */
+	u16			min_pressure;
+	int			vref;		/* non-zero to leave vref on */
+};
+
+static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
+{
+	int err;
+
+	err = tsc->mfd->read_dev(tsc->mfd, reg, 1, data);
+
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int tps6507x_write_u8(struct tps6507x_ts *tsc, u8 reg, u8 data)
+{
+	return tsc->mfd->write_dev(tsc->mfd, reg, 1, &data);
+}
+
+static s32 tps6507x_adc_conversion(struct tps6507x_ts *tsc,
+				   u8 tsc_mode, u16 *value)
+{
+	s32 ret;
+	u8 adc_status;
+	u8 result;
+
+	/* Route input signal to A/D converter */
+
+	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE, tsc_mode);
+	if (ret) {
+		dev_err(tsc->dev, "TSC mode read failed\n");
+		goto err;
+	}
+
+	/* Start A/D conversion */
+
+	ret = tps6507x_write_u8(tsc, TPS6507X_REG_ADCONFIG,
+				TPS6507X_ADCONFIG_CONVERT_TS);
+	if (ret) {
+		dev_err(tsc->dev, "ADC config write failed\n");
+		return ret;
+	}
+
+	do {
+		ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADCONFIG,
+				       &adc_status);
+		if (ret) {
+			dev_err(tsc->dev, "ADC config read failed\n");
+			goto err;
+		}
+	} while (adc_status & TPS6507X_ADCONFIG_START_CONVERSION);
+
+	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_2, &result);
+	if (ret) {
+		dev_err(tsc->dev, "ADC result 2 read failed\n");
+		goto err;
+	}
+
+	*value = (result & TPS6507X_REG_ADRESULT_2_MASK) << 8;
+
+	ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_1, &result);
+	if (ret) {
+		dev_err(tsc->dev, "ADC result 1 read failed\n");
+		goto err;
+	}
+
+	*value |= result;
+
+	dev_dbg(tsc->dev, "TSC channel %d = 0x%X\n", tsc_mode, *value);
+
+err:
+	return ret;
+}
+
+/* Need to call tps6507x_adc_standby() after using A/D converter for the
+ * touch screen interrupt to work properly.
+ */
+
+static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
+{
+	s32 ret;
+	s32 loops = 0;
+	u8 val;
+
+	ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
+				TPS6507X_ADCONFIG_INPUT_TSC);
+	if (ret)
+		return ret;
+
+	ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
+				TPS6507X_TSCMODE_STANDBY);
+	if (ret)
+		return ret;
+
+	ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
+	if (ret)
+		return ret;
+
+	while (val & TPS6507X_REG_TSC_INT) {
+		mdelay(10);
+		ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
+		if (ret)
+			return ret;
+		loops++;
+	}
+
+	return ret;
+}
+
+static void tps6507x_ts_handler(struct work_struct *work)
+{
+	struct tps6507x_ts *tsc =  container_of(work,
+				struct tps6507x_ts, work.work);
+	struct input_dev *input_dev = tsc->input_dev;
+	int pendown;
+	int schd;
+	int poll = 0;
+	s32 ret;
+
+	ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
+				       &tsc->tc.pressure);
+	if (ret)
+		goto done;
+
+	pendown = tsc->tc.pressure > tsc->min_pressure;
+
+	if (unlikely(!pendown && tsc->pendown)) {
+		dev_dbg(tsc->dev, "UP\n");
+		input_report_key(input_dev, BTN_TOUCH, 0);
+		input_report_abs(input_dev, ABS_PRESSURE, 0);
+		input_sync(input_dev);
+		tsc->pendown = 0;
+	}
+
+	if (pendown) {
+
+		if (!tsc->pendown) {
+			dev_dbg(tsc->dev, "DOWN\n");
+			input_report_key(input_dev, BTN_TOUCH, 1);
+		} else
+			dev_dbg(tsc->dev, "still down\n");
+
+		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
+					       &tsc->tc.x);
+		if (ret)
+			goto done;
+
+		ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
+					       &tsc->tc.y);
+		if (ret)
+			goto done;
+
+		input_report_abs(input_dev, ABS_X, tsc->tc.x);
+		input_report_abs(input_dev, ABS_Y, tsc->tc.y);
+		input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
+		input_sync(input_dev);
+		tsc->pendown = 1;
+		poll = 1;
+	}
+
+done:
+	/* always poll if not using interrupts */
+	poll = 1;
+
+	if (poll) {
+		schd = queue_delayed_work(tsc->wq, &tsc->work,
+					  tsc->poll_period * HZ / 1000);
+		if (schd)
+			tsc->polling = 1;
+		else {
+			tsc->polling = 0;
+			dev_err(tsc->dev, "re-schedule failed");
+		}
+	} else
+		tsc->polling = 0;
+
+	ret = tps6507x_adc_standby(tsc);
+}
+
+static int tps6507x_ts_probe(struct platform_device *pdev)
+{
+	int error;
+	struct tps6507x_ts *tsc;
+	struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
+	struct touchscreen_init_data *init_data;
+	struct input_dev *input_dev;
+	struct tps6507x_board *tps_board;
+	int schd;
+
+	/**
+	 * tps_board points to pmic related constants
+	 * coming from the board-evm file.
+	 */
+
+	tps_board = (struct tps6507x_board *)tps6507x_dev->dev->platform_data;
+
+	if (!tps_board) {
+		dev_err(tps6507x_dev->dev,
+			"Could not find tps6507x platform data\n");
+		return -EIO;
+	}
+
+	/**
+	 * init_data points to array of regulator_init structures
+	 * coming from the board-evm file.
+	 */
+
+	init_data = tps_board->tps6507x_ts_init_data;
+
+	tsc = kzalloc(sizeof(struct tps6507x_ts), GFP_KERNEL);
+	if (!tsc) {
+		dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
+		error = -ENOMEM;
+		goto err0;
+	}
+
+	tps6507x_dev->ts = tsc;
+	tsc->mfd = tps6507x_dev;
+	tsc->dev = tps6507x_dev->dev;
+	input_dev = input_allocate_device();
+	if (!input_dev) {
+		dev_err(tsc->dev, "Failed to allocate input device.\n");
+		error = -ENOMEM;
+		goto err1;
+	}
+
+	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+
+	input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
+	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
+
+	input_dev->name = "TPS6507x Touchscreen";
+	input_dev->id.bustype = BUS_I2C;
+	input_dev->dev.parent = tsc->dev;
+
+	snprintf(tsc->phys, sizeof(tsc->phys),
+		 "%s/input0", dev_name(tsc->dev));
+	input_dev->phys = tsc->phys;
+
+	dev_dbg(tsc->dev, "device: %s\n", input_dev->phys);
+
+	input_set_drvdata(input_dev, tsc);
+
+	tsc->input_dev = input_dev;
+
+	INIT_DELAYED_WORK(&tsc->work, tps6507x_ts_handler);
+	tsc->wq = create_workqueue("TPS6507x Touchscreen");
+
+	if (init_data) {
+		tsc->poll_period = init_data->poll_period;
+		tsc->vref = init_data->vref;
+		tsc->min_pressure = init_data->min_pressure;
+		input_dev->id.vendor = init_data->vendor;
+		input_dev->id.product = init_data->product;
+		input_dev->id.version = init_data->version;
+	} else {
+		tsc->poll_period = TSC_DEFAULT_POLL_PERIOD;
+		tsc->min_pressure = TPS_DEFAULT_MIN_PRESSURE;
+	}
+
+	error = tps6507x_adc_standby(tsc);
+	if (error)
+		goto err2;
+
+	error = input_register_device(input_dev);
+	if (error)
+		goto err2;
+
+	schd = queue_delayed_work(tsc->wq, &tsc->work,
+				  tsc->poll_period * HZ / 1000);
+
+	if (schd)
+		tsc->polling = 1;
+	else {
+		tsc->polling = 0;
+		dev_err(tsc->dev, "schedule failed");
+		goto err2;
+	 }
+
+	return 0;
+
+err2:
+	cancel_delayed_work(&tsc->work);
+	flush_workqueue(tsc->wq);
+	destroy_workqueue(tsc->wq);
+	tsc->wq = 0;
+	input_free_device(input_dev);
+err1:
+	kfree(tsc);
+	tps6507x_dev->ts = NULL;
+err0:
+	return error;
+}
+
+static int __devexit tps6507x_ts_remove(struct platform_device *pdev)
+{
+	struct tps6507x_dev *tps6507x_dev = platform_get_drvdata(pdev);
+	struct tps6507x_ts *tsc = tps6507x_dev->ts;
+	struct input_dev *input_dev = tsc->input_dev;
+
+	if (!tsc)
+		return 0;
+
+	cancel_delayed_work(&tsc->work);
+	flush_workqueue(tsc->wq);
+	destroy_workqueue(tsc->wq);
+	tsc->wq = 0;
+
+	input_free_device(input_dev);
+
+	tps6507x_dev->ts = NULL;
+	kfree(tsc);
+
+	return 0;
+}
+
+static struct platform_driver tps6507x_ts_driver = {
+	.driver = {
+		.name = "tps6507x-ts",
+		.owner = THIS_MODULE,
+	},
+	.probe = tps6507x_ts_probe,
+	.remove = __devexit_p(tps6507x_ts_remove),
+};
+
+static int __init tps6507x_ts_init(void)
+{
+	return platform_driver_register(&tps6507x_ts_driver);
+}
+module_init(tps6507x_ts_init);
+
+static void __exit tps6507x_ts_exit(void)
+{
+	platform_driver_unregister(&tps6507x_ts_driver);
+}
+module_exit(tps6507x_ts_exit);
+
+MODULE_AUTHOR("Todd Fischer <[e-mail]>");
+MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:tps6507x-tsc");

drivers/mfd/tps6507x.c

···
 	{
 		.name = "tps6507x-pmic",
 	},
+	{
+		.name = "tps6507x-ts",
+	},
 };
 
 

include/linux/input/tps6507x-ts.h

···
+/* linux/i2c/tps6507x-ts.h
+ *
+ * Functions to access TPS65070 touch screen chip.
+ *
+ * Copyright (c) 2009 RidgeRun ([e-mail])
+ *
+ *
+ *  For licencing details see kernel-base/COPYING
+ */
+
+#ifndef __LINUX_I2C_TPS6507X_TS_H
+#define __LINUX_I2C_TPS6507X_TS_H
+
+/* Board specific touch screen initial values */
+struct touchscreen_init_data {
+	int	poll_period;	/* ms */
+	int	vref;		/* non-zero to leave vref on */
+	__u16	min_pressure;	/* min reading to be treated as a touch */
+	__u16	vendor;
+	__u16	product;
+	__u16	version;
+};
+
+#endif /*  __LINUX_I2C_TPS6507X_TS_H */

include/linux/mfd/tps6507x.h

···
 
 struct tps6507x_board {
 	struct regulator_init_data *tps6507x_pmic_init_data;
+	struct touchscreen_init_data *tps6507x_ts_init_data;
 };
 
 /**
···
 
 	/* Client devices */
 	struct tps6507x_pmic *pmic;
+	struct tps6507x_ts *ts;
 };
 
 #endif /*  __LINUX_MFD_TPS6507X_H */