[PATCH] input: add support for TI Touchscreen controller.

["Patil, Rachna" <rachna@ti.com>]

This patch adds support for TI's touchscreen
controller for a 4/5/8 wire resistive panel
that is directly fed to the ADC.

This touchscreen controller will be part of
an upcoming TI SoC and has been tested on
an emulation platform.

Signed-off-by: Patil, Rachna <rachna@ti.com>
---
 drivers/input/touchscreen/Kconfig     |   11 +
 drivers/input/touchscreen/Makefile    |    1 +
 drivers/input/touchscreen/ti_tscadc.c |  417 +++++++++++++++++++++++++++++++++
 include/linux/input/ti_tsc.h          |    7 +
 4 files changed, 436 insertions(+), 0 deletions(-)
 create mode 100644 drivers/input/touchscreen/ti_tscadc.c
 create mode 100644 include/linux/input/ti_tsc.h

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 44589f5..9d5d3ba 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -704,4 +704,15 @@ config TOUCHSCREEN_TPS6507X
 	  To compile this driver as a module, choose M here: the
 	  module will be called tps6507x_ts.
 
+config TOUCHSCREEN_TI_TSCADC
+	tristate "TI Touchscreen Interface"
+	help
+	  Say Y here if you have 4/5/8 wire touchscreen controller
+	  to be connected to the ADC controller on your TI SoC.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ti_tscadc.
+
 endif
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 51b08b0..82d3098 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -58,3 +58,4 @@ 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
+obj-$(CONFIG_TOUCHSCREEN_TI_TSCADC)	+= ti_tscadc.o
diff --git a/drivers/input/touchscreen/ti_tscadc.c b/drivers/input/touchscreen/ti_tscadc.c
new file mode 100644
index 0000000..0308f71
--- /dev/null
+++ b/drivers/input/touchscreen/ti_tscadc.c
@@ -0,0 +1,417 @@
+/*
+ * 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_tsc.h>
+
+#define TSCADC_REG_IRQEOI		0x020
+#define TSCADC_REG_IRQSTATUS		0x028
+#define TSCADC_REG_IRQENABLE		0x02C
+#define TSCADC_REG_IRQWAKEUP		0x034
+#define TSCADC_REG_CTRL			0x040
+#define TSCADC_REG_ADCFSM		0x044
+#define TSCADC_REG_CLKDIV		0x04C
+#define TSCADC_REG_SE			0x054
+#define TSCADC_REG_IDLECONFIG		0x058
+#define TSCADC_REG_CHARGECONFIG		0x05C
+#define TSCADC_REG_STEPCONFIG1		0x064
+#define TSCADC_REG_STEPDELAY1		0x068
+#define TSCADC_REG_STEPCONFIG2		0x06C
+#define TSCADC_REG_STEPDELAY2		0x070
+#define TSCADC_REG_FIFO0		0x100
+
+/*	Register Bitfields	*/
+#define TSCADC_IRQWKUP_ENB		BIT(0)
+#define TSCADC_STPENB_STEPENB		(7 << 0)
+#define TSCADC_IRQENB_IRQHWPEN		BIT(10)
+#define TSCADC_IRQENB_IRQEOS		BIT(1)
+#define TSCADC_IRQENB_FIFO_OVERFLOW	BIT(3)
+#define TSCADC_IRQENB_PENUP		BIT(9)
+#define TSCADC_STEPCONFIG_MODE_HWSYNC	0x3
+#define TSCADC_STEPCONFIG_2SAMPLES_AVG	BIT(2)
+#define TSCADC_STEPCONFIG_XPP		BIT(5)
+#define TSCADC_STEPCONFIG_XNN		BIT(6)
+#define TSCADC_STEPCONFIG_YPP		BIT(7)
+#define TSCADC_STEPCONFIG_YNN		BIT(8)
+#define TSCADC_STEPCONFIG_XNP		BIT(9)
+#define TSCADC_STEPCONFIG_YPN		BIT(10)
+#define TSCADC_STEPCONFIG_RFP_X		(1 << 12)
+#define TSCADC_STEPCONFIG_RFP_4_Y	(1 << 13)
+#define TSCADC_STEPCONFIG_RFP_5_Y	(1 << 12)
+#define TSCADC_STEPCONFIG_RFP_8_Y	(1 << 13)
+#define TSCADC_STEPCONFIG_INM		(1 << 18)
+#define TSCADC_STEPCONFIG_INP_4		(1 << 20)
+#define TSCADC_STEPCONFIG_INP_5		(1 << 21)
+#define TSCADC_STEPCONFIG_INP_8_X	(3 << 20)
+#define TSCADC_STEPCONFIG_INP_8_Y	(1 << 21)
+#define TSCADC_STEPCONFIG_RFM_4_X	(1 << 23)
+#define TSCADC_STEPCONFIG_RFM_5_X	(1 << 24)
+#define TSCADC_STEPCONFIG_RFM_8_X	(1 << 23)
+#define TSCADC_STEPCONFIG_RFM_Y		(1 << 24)
+#define TSCADC_STEPCONFIG_OPENDLY	(0xf << 0)
+#define TSCADC_STEPCONFIG_SAMPLEDLY	BIT(25)
+#define TSCADC_STEPCHARGE_INM		BIT(18)
+#define TSCADC_STEPCHARGE_RFM		(3 << 23)
+#define TSCADC_CNTRLREG_TSCSSENB	BIT(0)
+#define TSCADC_CNTRLREG_STEPID		BIT(1)
+#define TSCADC_CNTRLREG_STEPCONFIGWRT	BIT(2)
+#define TSCADC_CNTRLREG_TSCENB		BIT(7)
+#define TSCADC_CNTRLREG_4WIRE		(0x1 << 5)
+#define TSCADC_CNTRLREG_5WIRE		(0x1 << 6)
+#define TSCADC_CNTRLREG_8WIRE		(0x3 << 5)
+#define TSCADC_ADCFSM_STEPID		0x10
+#define TSCADC_ADCFSM_FSM		BIT(5)
+
+#define ADC_CLK				3000000
+
+#define MAX_12BIT                       ((1 << 12) - 1)
+
+struct tscadc {
+	struct input_dev	*input;
+	int			wires;
+	struct clk		*clk;
+	int			irq;
+	void __iomem		*tsc_base;
+};
+
+static inline unsigned int tscadc_readl(struct tscadc *ts, unsigned int reg)
+{
+	return readl(ts->tsc_base + reg);
+}
+
+static inline void tscadc_writel(struct tscadc *tsc, unsigned int reg,
+					unsigned int val)
+{
+	writel(val, tsc->tsc_base + reg);
+}
+
+void tsc_idle_config(struct tscadc *ts_config)
+{
+	/* Idle mode touch screen config */
+	unsigned int	 idleconfig;
+
+	idleconfig = TSCADC_STEPCONFIG_YNN |
+				TSCADC_STEPCONFIG_RFP_X |
+				TSCADC_STEPCONFIG_INM ;
+
+	if (ts_config->wires == 4) {
+		idleconfig |= TSCADC_STEPCONFIG_INP_4 |
+				TSCADC_STEPCONFIG_RFM_4_X;
+
+	} else if (ts_config->wires == 5) {
+		idleconfig |= TSCADC_STEPCONFIG_INP_5 |
+				TSCADC_STEPCONFIG_RFM_5_X;
+
+	} else {
+		idleconfig |= TSCADC_STEPCONFIG_INP_4 |
+				TSCADC_STEPCONFIG_RFM_8_X;
+	}
+	tscadc_writel(ts_config, TSCADC_REG_IDLECONFIG, idleconfig);
+}
+
+static irqreturn_t tscadc_interrupt(int irq, void *dev)
+{
+	struct tscadc		*ts_dev = (struct tscadc *)dev;
+	struct input_dev	*input_dev = ts_dev->input;
+	unsigned int		status, store, cntrlreg, irqclr = 0;
+	int			absx, absy;
+	int			charge, fsm;
+
+	status = tscadc_readl(ts_dev, TSCADC_REG_IRQSTATUS);
+	tscadc_writel(ts_dev, TSCADC_REG_SE, 0x0);
+
+	/* Pen touch event */
+	if (status & TSCADC_IRQENB_IRQHWPEN)
+		irqclr = status & TSCADC_IRQENB_IRQHWPEN;
+
+	if (status & TSCADC_IRQENB_PENUP) {
+		/* Pen up event */
+		charge = TSCADC_STEPCHARGE_INM | TSCADC_STEPCHARGE_RFM;
+		tscadc_writel(ts_dev, TSCADC_REG_CHARGECONFIG, charge);
+		input_report_key(input_dev, BTN_TOUCH, 0);
+		tsc_idle_config(ts_dev);
+		irqclr |= status & TSCADC_IRQENB_PENUP;
+
+	}
+	if (status & TSCADC_IRQENB_IRQEOS) {
+		/* ADC is done with sampling, ready to read the data */
+		absx = tscadc_readl(ts_dev, TSCADC_REG_FIFO0);
+		absy = tscadc_readl(ts_dev, TSCADC_REG_FIFO0);
+
+		input_report_abs(input_dev, ABS_X, absx);
+		input_report_abs(input_dev, ABS_Y, absy);
+		input_report_key(input_dev, BTN_TOUCH, 1);
+
+		irqclr |= status & TSCADC_IRQENB_IRQEOS;
+
+	}
+	if (status & TSCADC_IRQENB_FIFO_OVERFLOW) {
+		/* FIFO overflow condition */
+		cntrlreg = tscadc_readl(ts_dev, TSCADC_REG_CTRL);
+		cntrlreg &= ~TSCADC_CNTRLREG_TSCSSENB;
+		tscadc_writel(ts_dev, TSCADC_REG_CTRL, cntrlreg);
+
+		irqclr |= status & TSCADC_IRQENB_FIFO_OVERFLOW;
+	}
+
+	tscadc_writel(ts_dev, TSCADC_REG_IRQSTATUS, irqclr);
+	fsm = tscadc_readl(ts_dev, TSCADC_REG_ADCFSM);
+	if ((fsm & TSCADC_ADCFSM_FSM) &&
+			(fsm & TSCADC_ADCFSM_STEPID)) {
+		store = tscadc_readl(ts_dev, TSCADC_REG_CTRL);
+		store |= TSCADC_CNTRLREG_TSCSSENB;
+		tscadc_writel(ts_dev, TSCADC_REG_CTRL, store);
+	}
+
+	 /* check pending interrupts */
+	tscadc_writel(ts_dev, TSCADC_REG_IRQEOI, 0x0);
+
+	tscadc_writel(ts_dev, TSCADC_REG_SE, TSCADC_STPENB_STEPENB);
+	return IRQ_HANDLED;
+}
+
+/*
+* The functions for inserting/removing driver as a module.
+*/
+
+static	int __devinit tscadc_probe(struct platform_device *pdev)
+{
+	struct tscadc			*ts_dev;
+	struct input_dev		*input_dev;
+	int				err;
+	int				clk_value;
+	int				clock_rate, ctrl, irqenable;
+	struct	tsc_data		*pdata = pdev->dev.platform_data;
+	struct resource			*res;
+	int				stepconfig1, stepconfig2, delay;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "no memory resource defined.\n");
+		return -ENXIO;
+	}
+
+	/* Allocate memory for device */
+	ts_dev = kzalloc(sizeof(struct tscadc), GFP_KERNEL);
+	if (!ts_dev) {
+		dev_err(&pdev->dev, "failed to allocate memory.\n");
+		return -ENOMEM;
+	}
+
+	input_dev = input_allocate_device();
+	if (!input_dev) {
+		dev_err(&pdev->dev, "failed to allocate input device.\n");
+		err = -EBUSY;
+		goto err_free_mem;
+	}
+	ts_dev->input = input_dev;
+
+	ts_dev->irq = platform_get_irq(pdev, 0);
+	if (ts_dev->irq < 0) {
+		dev_err(&pdev->dev, "no irq ID is specified.\n");
+		err = -ENODEV;
+		goto err_free_dev;
+	}
+
+	ts_dev->tsc_base = ioremap(res->start, resource_size(res));
+	if (!(ts_dev->tsc_base)) {
+		dev_err(&pdev->dev, "failed to map registers.\n");
+		err = -ENOMEM;
+		goto err_release_mem;
+	}
+
+	err = request_irq(ts_dev->irq, tscadc_interrupt, IRQF_DISABLED,
+	pdev->dev.driver->name, ts_dev);
+	if (err) {
+		dev_err(&pdev->dev, "failed to allocate irq.\n");
+		goto err_unmap_regs;
+	}
+
+	ts_dev->clk = clk_get(&pdev->dev, "tsc_clk");
+	if (IS_ERR(ts_dev->clk)) {
+		dev_err(&pdev->dev, "failed to get ts_clk\n");
+		err = PTR_ERR(ts_dev->clk);
+		goto err_free_irq;
+	}
+	clk_enable(ts_dev->clk);
+
+	clock_rate = clk_get_rate(ts_dev->clk);
+	clk_value = clock_rate / ADC_CLK;
+	if (clk_value < 7) {
+		dev_err(&pdev->dev, "clock input less than min clock requirement\n");
+		goto err_fail;
+	}
+	/* TSCADC_CLKDIV needs to be configured to the value minus 1 */
+	clk_value = clk_value - 1;
+	tscadc_writel(ts_dev, TSCADC_REG_CLKDIV, clk_value);
+
+	 /* Enable wake-up of the SoC using touchscreen */
+	tscadc_writel(ts_dev, TSCADC_REG_IRQWAKEUP, TSCADC_IRQWKUP_ENB);
+
+	ts_dev->wires = pdata->wires;
+
+	/* Set the control register bits */
+	ctrl = TSCADC_CNTRLREG_STEPCONFIGWRT |
+			TSCADC_CNTRLREG_TSCENB |
+			TSCADC_CNTRLREG_STEPID;
+	if (ts_dev->wires == 4)
+		ctrl |= TSCADC_CNTRLREG_4WIRE;
+	else if (ts_dev->wires == 5)
+		ctrl |= TSCADC_CNTRLREG_5WIRE;
+	else
+		ctrl |= TSCADC_CNTRLREG_8WIRE;
+	tscadc_writel(ts_dev, TSCADC_REG_CTRL, ctrl);
+	tscadc_readl(ts_dev, TSCADC_REG_CTRL);
+
+	/* Set register bits for Idel Config Mode */
+	tsc_idle_config(ts_dev);
+
+	/* IRQ Enable */
+	irqenable = TSCADC_IRQENB_IRQHWPEN |
+			TSCADC_IRQENB_IRQEOS |
+			TSCADC_IRQENB_PENUP | TSCADC_IRQENB_FIFO_OVERFLOW;
+	tscadc_writel(ts_dev, TSCADC_REG_IRQENABLE, irqenable);
+	tscadc_readl(ts_dev, TSCADC_REG_IRQENABLE);
+
+	/* Configure the Step registers */
+	stepconfig1 = TSCADC_STEPCONFIG_MODE_HWSYNC |
+			TSCADC_STEPCONFIG_2SAMPLES_AVG | TSCADC_STEPCONFIG_XPP |
+			TSCADC_STEPCONFIG_XNN | TSCADC_STEPCONFIG_INM |
+			TSCADC_STEPCONFIG_RFP_X;
+
+	stepconfig2 = TSCADC_STEPCONFIG_MODE_HWSYNC |
+			TSCADC_STEPCONFIG_2SAMPLES_AVG | TSCADC_STEPCONFIG_YNN |
+			TSCADC_STEPCONFIG_INM | TSCADC_STEPCONFIG_RFM_Y;
+	if (ts_dev->wires == 4) {
+		stepconfig1 |= TSCADC_STEPCONFIG_INP_4 |
+					TSCADC_STEPCONFIG_RFM_4_X;
+
+		stepconfig2 |= TSCADC_STEPCONFIG_YPP |
+					TSCADC_STEPCONFIG_RFP_4_Y;
+
+	} else if (ts_dev->wires == 5) {
+		stepconfig1 |= TSCADC_STEPCONFIG_YPP |
+				TSCADC_STEPCONFIG_YNN |
+				TSCADC_STEPCONFIG_INP_5 |
+				TSCADC_STEPCONFIG_RFM_5_X;
+
+		stepconfig2 |= TSCADC_STEPCONFIG_XPP |
+				TSCADC_STEPCONFIG_XNP |
+				TSCADC_STEPCONFIG_YPN |
+				TSCADC_STEPCONFIG_RFP_5_Y |
+				TSCADC_STEPCONFIG_INP_5;
+	} else{
+		stepconfig1 |= TSCADC_STEPCONFIG_INP_8_X |
+				TSCADC_STEPCONFIG_RFM_8_X;
+
+		stepconfig2 |= TSCADC_STEPCONFIG_YPP |
+				TSCADC_STEPCONFIG_RFP_8_Y |
+				TSCADC_STEPCONFIG_INP_8_Y;
+	}
+	delay = TSCADC_STEPCONFIG_OPENDLY | TSCADC_STEPCONFIG_SAMPLEDLY;
+
+	tscadc_writel(ts_dev, TSCADC_REG_STEPCONFIG1, stepconfig1);
+	tscadc_writel(ts_dev, TSCADC_REG_STEPDELAY1, delay);
+	tscadc_writel(ts_dev, TSCADC_REG_STEPCONFIG2, stepconfig2);
+	tscadc_writel(ts_dev, TSCADC_REG_STEPDELAY2, delay);
+
+	tscadc_writel(ts_dev, TSCADC_REG_SE, TSCADC_STPENB_STEPENB);
+
+	ctrl |= TSCADC_CNTRLREG_TSCSSENB;
+	tscadc_writel(ts_dev, TSCADC_REG_CTRL, ctrl);
+
+	input_dev->name = "ti-tsc-adcc";
+	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);
+
+	/* register to the input system */
+	err = input_register_device(input_dev);
+	if (err)
+		goto err_fail;
+
+	return 0;
+
+err_fail:
+	clk_disable(ts_dev->clk);
+	clk_put(ts_dev->clk);
+err_free_irq:
+	free_irq(ts_dev->irq, ts_dev);
+err_unmap_regs:
+	iounmap(ts_dev->tsc_base);
+err_release_mem:
+	release_mem_region(res->start, resource_size(res));
+err_free_dev:
+	input_free_device(ts_dev->input);
+err_free_mem:
+	kfree(ts_dev);
+	return err;
+}
+
+static int __devexit tscadc_remove(struct platform_device *pdev)
+{
+	struct tscadc		*ts_dev = dev_get_drvdata(&pdev->dev);
+	struct resource		*res;
+
+	free_irq(ts_dev->irq, ts_dev);
+
+	input_unregister_device(ts_dev->input);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	iounmap(ts_dev->tsc_base);
+	release_mem_region(res->start, resource_size(res));
+
+	clk_disable(ts_dev->clk);
+	clk_put(ts_dev->clk);
+
+	kfree(ts_dev);
+
+	return 0;
+}
+
+static struct platform_driver ti_tsc_driver = {
+	.probe	  = tscadc_probe,
+	.remove	 = __devexit_p(tscadc_remove),
+	.driver	 = {
+		.name   = "tsc",
+	},
+};
+
+static int __init ti_tsc_init(void)
+{
+	return platform_driver_register(&ti_tsc_driver);
+}
+
+static void __exit ti_tsc_exit(void)
+{
+	platform_driver_unregister(&ti_tsc_driver);
+}
+
+module_init(ti_tsc_init);
+module_exit(ti_tsc_exit);
diff --git a/include/linux/input/ti_tsc.h b/include/linux/input/ti_tsc.h
new file mode 100644
index 0000000..f499773
--- /dev/null
+++ b/include/linux/input/ti_tsc.h
@@ -0,0 +1,7 @@
+/* touch screen wire configuration */
+
+struct tsc_data {
+	int wires;	/* Wires refer to application modes
+			i.e. 4/5/8 wire touchscreen support
+			on the platform */
+};
-- 
1.6.2.4