1 files changed, 398 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
new file mode 100644
index 000000000000..7a18a8a15228
--- /dev/null
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -0,0 +1,398 @@
+/*
+ * TI Touch Screen driver
+ *
+ * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/input/ti_am335x_tsc.h>
+#include <linux/delay.h>
+
+#include <linux/mfd/ti_am335x_tscadc.h>
+
+#define ADCFSM_STEPID		0x10
+#define SEQ_SETTLE		275
+#define MAX_12BIT		((1 << 12) - 1)
+
+struct titsc {
+	struct input_dev	*input;
+	struct ti_tscadc_dev	*mfd_tscadc;
+	unsigned int		irq;
+	unsigned int		wires;
+	unsigned int		x_plate_resistance;
+	bool			pen_down;
+	int			steps_to_configure;
+};
+
+static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
+{
+	return readl(ts->mfd_tscadc->tscadc_base + reg);
+}
+
+static void titsc_writel(struct titsc *tsc, unsigned int reg,
+					unsigned int val)
+{
+	writel(val, tsc->mfd_tscadc->tscadc_base + reg);
+}
+
+static void titsc_step_config(struct titsc *ts_dev)
+{
+	unsigned int	config;
+	int i, total_steps;
+
+	/* Configure the Step registers */
+	total_steps = 2 * ts_dev->steps_to_configure;
+
+	config = STEPCONFIG_MODE_HWSYNC |
+			STEPCONFIG_AVG_16 | STEPCONFIG_XPP;
+	switch (ts_dev->wires) {
+	case 4:
+		config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
+		break;
+	case 5:
+		config |= STEPCONFIG_YNN |
+				STEPCONFIG_INP_AN4 | STEPCONFIG_XNN |
+				STEPCONFIG_YPP;
+		break;
+	case 8:
+		config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
+		break;
+	}
+
+	for (i = 1; i <= ts_dev->steps_to_configure; i++) {
+		titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
+		titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
+	}
+
+	config = 0;
+	config = STEPCONFIG_MODE_HWSYNC |
+			STEPCONFIG_AVG_16 | STEPCONFIG_YNN |
+			STEPCONFIG_INM_ADCREFM | STEPCONFIG_FIFO1;
+	switch (ts_dev->wires) {
+	case 4:
+		config |= STEPCONFIG_YPP;
+		break;
+	case 5:
+		config |= STEPCONFIG_XPP | STEPCONFIG_INP_AN4 |
+				STEPCONFIG_XNP | STEPCONFIG_YPN;
+		break;
+	case 8:
+		config |= STEPCONFIG_YPP;
+		break;
+	}
+
+	for (i = (ts_dev->steps_to_configure + 1); i <= total_steps; i++) {
+		titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
+		titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
+	}
+
+	config = 0;
+	/* Charge step configuration */
+	config = STEPCONFIG_XPP | STEPCONFIG_YNN |
+			STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
+			STEPCHARGE_INM_AN1 | STEPCHARGE_INP_AN1;
+
+	titsc_writel(ts_dev, REG_CHARGECONFIG, config);
+	titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);
+
+	config = 0;
+	/* Configure to calculate pressure */
+	config = STEPCONFIG_MODE_HWSYNC |
+			STEPCONFIG_AVG_16 | STEPCONFIG_YPP |
+			STEPCONFIG_XNN | STEPCONFIG_INM_ADCREFM;
+	titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 1), config);
+	titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 1),
+			STEPCONFIG_OPENDLY);
+
+	config |= STEPCONFIG_INP_AN3 | STEPCONFIG_FIFO1;
+	titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 2), config);
+	titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 2),
+			STEPCONFIG_OPENDLY);
+
+	titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC);
+}
+
+static void titsc_read_coordinates(struct titsc *ts_dev,
+				    unsigned int *x, unsigned int *y)
+{
+	unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT);
+	unsigned int prev_val_x = ~0, prev_val_y = ~0;
+	unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
+	unsigned int read, diff;
+	unsigned int i, channel;
+
+	/*
+	 * Delta filter is used to remove large variations in sampled
+	 * values from ADC. The filter tries to predict where the next
+	 * coordinate could be. This is done by taking a previous
+	 * coordinate and subtracting it form current one. Further the
+	 * algorithm compares the difference with that of a present value,
+	 * if true the value is reported to the sub system.
+	 */
+	for (i = 0; i < fifocount - 1; i++) {
+		read = titsc_readl(ts_dev, REG_FIFO0);
+		channel = read & 0xf0000;
+		channel = channel >> 0x10;
+		if ((channel >= 0) && (channel < ts_dev->steps_to_configure)) {
+			read &= 0xfff;
+			diff = abs(read - prev_val_x);
+			if (diff < prev_diff_x) {
+				prev_diff_x = diff;
+				*x = read;
+			}
+			prev_val_x = read;
+		}
+
+		read = titsc_readl(ts_dev, REG_FIFO1);
+		channel = read & 0xf0000;
+		channel = channel >> 0x10;
+		if ((channel >= ts_dev->steps_to_configure) &&
+			(channel < (2 * ts_dev->steps_to_configure - 1))) {
+			read &= 0xfff;
+			diff = abs(read - prev_val_y);
+			if (diff < prev_diff_y) {
+				prev_diff_y = diff;
+				*y = read;
+			}
+			prev_val_y = read;
+		}
+	}
+}
+
+static irqreturn_t titsc_irq(int irq, void *dev)
+{
+	struct titsc *ts_dev = dev;
+	struct input_dev *input_dev = ts_dev->input;
+	unsigned int status, irqclr = 0;
+	unsigned int x = 0, y = 0;
+	unsigned int z1, z2, z;
+	unsigned int fsm;
+	unsigned int fifo1count, fifo0count;
+	int i;
+
+	status = titsc_readl(ts_dev, REG_IRQSTATUS);
+	if (status & IRQENB_FIFO0THRES) {
+		titsc_read_coordinates(ts_dev, &x, &y);
+
+		z1 = titsc_readl(ts_dev, REG_FIFO0) & 0xfff;
+		z2 = titsc_readl(ts_dev, REG_FIFO1) & 0xfff;
+
+		fifo1count = titsc_readl(ts_dev, REG_FIFO1CNT);
+		for (i = 0; i < fifo1count; i++)
+			titsc_readl(ts_dev, REG_FIFO1);
+
+		fifo0count = titsc_readl(ts_dev, REG_FIFO0CNT);
+		for (i = 0; i < fifo0count; i++)
+			titsc_readl(ts_dev, REG_FIFO0);
+
+		if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
+			/*
+			 * Calculate pressure using formula
+			 * Resistance(touch) = x plate resistance *
+			 * x postion/4096 * ((z2 / z1) - 1)
+			 */
+			z = z2 - z1;
+			z *= x;
+			z *= ts_dev->x_plate_resistance;
+			z /= z1;
+			z = (z + 2047) >> 12;
+
+			if (z <= MAX_12BIT) {
+				input_report_abs(input_dev, ABS_X, x);
+				input_report_abs(input_dev, ABS_Y, y);
+				input_report_abs(input_dev, ABS_PRESSURE, z);
+				input_report_key(input_dev, BTN_TOUCH, 1);
+				input_sync(input_dev);
+			}
+		}
+		irqclr |= IRQENB_FIFO0THRES;
+	}
+
+	/*
+	 * Time for sequencer to settle, to read
+	 * correct state of the sequencer.
+	 */
+	udelay(SEQ_SETTLE);
+
+	status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
+	if (status & IRQENB_PENUP) {
+		/* Pen up event */
+		fsm = titsc_readl(ts_dev, REG_ADCFSM);
+		if (fsm == ADCFSM_STEPID) {
+			ts_dev->pen_down = false;
+			input_report_key(input_dev, BTN_TOUCH, 0);
+			input_report_abs(input_dev, ABS_PRESSURE, 0);
+			input_sync(input_dev);
+		} else {
+			ts_dev->pen_down = true;
+		}
+		irqclr |= IRQENB_PENUP;
+	}
+
+	titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
+
+	titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC);
+	return IRQ_HANDLED;
+}
+
+/*
+ * The functions for inserting/removing driver as a module.
+ */
+
+static int __devinit titsc_probe(struct platform_device *pdev)
+{
+	struct titsc *ts_dev;
+	struct input_dev *input_dev;
+	struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
+	struct mfd_tscadc_board	*pdata;
+	int err;
+
+	pdata = tscadc_dev->dev->platform_data;
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "Could not find platform data\n");
+		return -EINVAL;
+	}
+
+	/* Allocate memory for device */
+	ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!ts_dev || !input_dev) {
+		dev_err(&pdev->dev, "failed to allocate memory.\n");
+		err = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	tscadc_dev->tsc = ts_dev;
+	ts_dev->mfd_tscadc = tscadc_dev;
+	ts_dev->input = input_dev;
+	ts_dev->irq = tscadc_dev->irq;
+	ts_dev->wires = pdata->tsc_init->wires;
+	ts_dev->x_plate_resistance = pdata->tsc_init->x_plate_resistance;
+	ts_dev->steps_to_configure = pdata->tsc_init->steps_to_configure;
+
+	err = request_irq(ts_dev->irq, titsc_irq,
+			  0, pdev->dev.driver->name, ts_dev);
+	if (err) {
+		dev_err(&pdev->dev, "failed to allocate irq.\n");
+		goto err_free_mem;
+	}
+
+	titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
+	titsc_step_config(ts_dev);
+	titsc_writel(ts_dev, REG_FIFO0THR, ts_dev->steps_to_configure);
+
+	input_dev->name = "ti-tsc";
+	input_dev->dev.parent = &pdev->dev;
+
+	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_12BIT, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
+	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
+
+	/* register to the input system */
+	err = input_register_device(input_dev);
+	if (err)
+		goto err_free_irq;
+
+	platform_set_drvdata(pdev, ts_dev);
+	return 0;
+
+err_free_irq:
+	free_irq(ts_dev->irq, ts_dev);
+err_free_mem:
+	input_free_device(input_dev);
+	kfree(ts_dev);
+	return err;
+}
+
+static int __devexit titsc_remove(struct platform_device *pdev)
+{
+	struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
+	struct titsc *ts_dev = tscadc_dev->tsc;
+
+	free_irq(ts_dev->irq, ts_dev);
+
+	input_unregister_device(ts_dev->input);
+
+	platform_set_drvdata(pdev, NULL);
+	kfree(ts_dev);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int titsc_suspend(struct device *dev)
+{
+	struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
+	struct titsc *ts_dev = tscadc_dev->tsc;
+	unsigned int idle;
+
+	if (device_may_wakeup(tscadc_dev->dev)) {
+		idle = titsc_readl(ts_dev, REG_IRQENABLE);
+		titsc_writel(ts_dev, REG_IRQENABLE,
+				(idle | IRQENB_HW_PEN));
+		titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
+	}
+	return 0;
+}
+
+static int titsc_resume(struct device *dev)
+{
+	struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
+	struct titsc *ts_dev = tscadc_dev->tsc;
+
+	if (device_may_wakeup(tscadc_dev->dev)) {
+		titsc_writel(ts_dev, REG_IRQWAKEUP,
+				0x00);
+		titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
+	}
+	titsc_step_config(ts_dev);
+	titsc_writel(ts_dev, REG_FIFO0THR,
+			ts_dev->steps_to_configure);
+	return 0;
+}
+
+static const struct dev_pm_ops titsc_pm_ops = {
+	.suspend = titsc_suspend,
+	.resume  = titsc_resume,
+};
+#define TITSC_PM_OPS (&titsc_pm_ops)
+#else
+#define TITSC_PM_OPS NULL
+#endif
+
+static struct platform_driver ti_tsc_driver = {
+	.probe	= titsc_probe,
+	.remove	= __devexit_p(titsc_remove),
+	.driver	= {
+		.name   = "tsc",
+		.owner	= THIS_MODULE,
+		.pm	= TITSC_PM_OPS,
+	},
+};
+module_platform_driver(ti_tsc_driver);
+
+MODULE_DESCRIPTION("TI touchscreen controller driver");
+MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
+MODULE_LICENSE("GPL");