Input: add driver for Atmel integrated touchscreen controller

The AT91SAM9RL SoC integrates a Touchscreen Controller which
can trigger ADC conversion periodically.

Signed-off-by: Justin Waters <[e-mail]>
Signed-off-by: Dan Liang <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called touchwin.
 
+config TOUCHSCREEN_ATMEL_TSADCC
+	tristate "Atmel Touchscreen Interface"
+	depends on ARCH_AT91SAM9RL
+	help
+	  Say Y here if you have a 4-wire touchscreen connected to the
+          ADC Controller on your Atmel SoC (such as the AT91SAM9RL).
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called atmel_tsadcc.
+
 config TOUCHSCREEN_UCB1400
 	tristate "Philips UCB1400 touchscreen"
 	select AC97_BUS

drivers/input/touchscreen/Makefile

···
 wm97xx-ts-y := wm97xx-core.o
 
 obj-$(CONFIG_TOUCHSCREEN_ADS7846)	+= ads7846.o
+obj-$(CONFIG_TOUCHSCREEN_ATMEL_TSADCC)	+= atmel_tsadcc.o
 obj-$(CONFIG_TOUCHSCREEN_BITSY)		+= h3600_ts_input.o
 obj-$(CONFIG_TOUCHSCREEN_CORGI)		+= corgi_ts.o
 obj-$(CONFIG_TOUCHSCREEN_GUNZE)		+= gunze.o

drivers/input/touchscreen/atmel_tsadcc.c

···
+/*
+ *  Atmel Touch Screen Driver
+ *
+ *  Copyright (c) 2008 ATMEL
+ *  Copyright (c) 2008 Dan Liang
+ *  Copyright (c) 2008 TimeSys Corporation
+ *  Copyright (c) 2008 Justin Waters
+ *
+ *  Based on touchscreen code from Atmel Corporation.
+ *
+ *  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/init.h>
+#include <linux/err.h>
+#include <linux/kernel.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>
+
+/* Register definitions based on AT91SAM9RL64 preliminary draft datasheet */
+
+#define ATMEL_TSADCC_CR		0x00	/* Control register */
+#define   ATMEL_TSADCC_SWRST	(1 << 0)	/* Software Reset*/
+#define	  ATMEL_TSADCC_START	(1 << 1)	/* Start conversion */
+
+#define ATMEL_TSADCC_MR		0x04	/* Mode register */
+#define	  ATMEL_TSADCC_TSAMOD	(3    <<  0)	/* ADC mode */
+#define	    ATMEL_TSADCC_TSAMOD_ADC_ONLY_MODE	(0x0)	/* ADC Mode */
+#define	    ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE	(0x1)	/* Touch Screen Only Mode */
+#define	  ATMEL_TSADCC_LOWRES	(1    <<  4)	/* Resolution selection */
+#define	  ATMEL_TSADCC_SLEEP	(1    <<  5)	/* Sleep mode */
+#define	  ATMEL_TSADCC_PENDET	(1    <<  6)	/* Pen Detect selection */
+#define	  ATMEL_TSADCC_PRESCAL	(0x3f <<  8)	/* Prescalar Rate Selection */
+#define	  ATMEL_TSADCC_STARTUP	(0x7f << 16)	/* Start Up time */
+#define	  ATMEL_TSADCC_SHTIM	(0xf  << 24)	/* Sample & Hold time */
+#define	  ATMEL_TSADCC_PENDBC	(0xf  << 28)	/* Pen Detect debouncing time */
+
+#define ATMEL_TSADCC_TRGR	0x08	/* Trigger register */
+#define	  ATMEL_TSADCC_TRGMOD	(7      <<  0)	/* Trigger mode */
+#define	    ATMEL_TSADCC_TRGMOD_NONE		(0 << 0)
+#define     ATMEL_TSADCC_TRGMOD_EXT_RISING	(1 << 0)
+#define     ATMEL_TSADCC_TRGMOD_EXT_FALLING	(2 << 0)
+#define     ATMEL_TSADCC_TRGMOD_EXT_ANY		(3 << 0)
+#define     ATMEL_TSADCC_TRGMOD_PENDET		(4 << 0)
+#define     ATMEL_TSADCC_TRGMOD_PERIOD		(5 << 0)
+#define     ATMEL_TSADCC_TRGMOD_CONTINUOUS	(6 << 0)
+#define   ATMEL_TSADCC_TRGPER	(0xffff << 16)	/* Trigger period */
+
+#define ATMEL_TSADCC_TSR	0x0C	/* Touch Screen register */
+#define	  ATMEL_TSADCC_TSFREQ	(0xf <<  0)	/* TS Frequency in Interleaved mode */
+#define	  ATMEL_TSADCC_TSSHTIM	(0xf << 24)	/* Sample & Hold time */
+
+#define ATMEL_TSADCC_CHER	0x10	/* Channel Enable register */
+#define ATMEL_TSADCC_CHDR	0x14	/* Channel Disable register */
+#define ATMEL_TSADCC_CHSR	0x18	/* Channel Status register */
+#define	  ATMEL_TSADCC_CH(n)	(1 << (n))	/* Channel number */
+
+#define ATMEL_TSADCC_SR		0x1C	/* Status register */
+#define	  ATMEL_TSADCC_EOC(n)	(1 << ((n)+0))	/* End of conversion for channel N */
+#define	  ATMEL_TSADCC_OVRE(n)	(1 << ((n)+8))	/* Overrun error for channel N */
+#define	  ATMEL_TSADCC_DRDY	(1 << 16)	/* Data Ready */
+#define	  ATMEL_TSADCC_GOVRE	(1 << 17)	/* General Overrun Error */
+#define	  ATMEL_TSADCC_ENDRX	(1 << 18)	/* End of RX Buffer */
+#define	  ATMEL_TSADCC_RXBUFF	(1 << 19)	/* TX Buffer full */
+#define	  ATMEL_TSADCC_PENCNT	(1 << 20)	/* Pen contact */
+#define	  ATMEL_TSADCC_NOCNT	(1 << 21)	/* No contact */
+
+#define ATMEL_TSADCC_LCDR	0x20	/* Last Converted Data register */
+#define	  ATMEL_TSADCC_DATA	(0x3ff << 0)	/* Channel data */
+
+#define ATMEL_TSADCC_IER	0x24	/* Interrupt Enable register */
+#define ATMEL_TSADCC_IDR	0x28	/* Interrupt Disable register */
+#define ATMEL_TSADCC_IMR	0x2C	/* Interrupt Mask register */
+#define ATMEL_TSADCC_CDR0	0x30	/* Channel Data 0 */
+#define ATMEL_TSADCC_CDR1	0x34	/* Channel Data 1 */
+#define ATMEL_TSADCC_CDR2	0x38	/* Channel Data 2 */
+#define ATMEL_TSADCC_CDR3	0x3C	/* Channel Data 3 */
+#define ATMEL_TSADCC_CDR4	0x40	/* Channel Data 4 */
+#define ATMEL_TSADCC_CDR5	0x44	/* Channel Data 5 */
+
+#define ADC_CLOCK	1000000
+
+struct atmel_tsadcc {
+	struct input_dev	*input;
+	char			phys[32];
+	struct clk		*clk;
+	int			irq;
+};
+
+static void __iomem		*tsc_base;
+
+#define atmel_tsadcc_read(reg)		__raw_readl(tsc_base + (reg))
+#define atmel_tsadcc_write(reg, val)	__raw_writel((val), tsc_base + (reg))
+
+static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
+{
+	struct input_dev *input_dev = ((struct atmel_tsadcc *)dev)->input;
+
+	unsigned int absx;
+	unsigned int absy;
+	unsigned int status;
+	unsigned int reg;
+
+	status = atmel_tsadcc_read(ATMEL_TSADCC_SR);
+	status &= atmel_tsadcc_read(ATMEL_TSADCC_IMR);
+
+	if (status & ATMEL_TSADCC_NOCNT) {
+		/* Contact lost */
+		reg = atmel_tsadcc_read(ATMEL_TSADCC_MR) | ATMEL_TSADCC_PENDBC;
+
+		atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
+		atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
+		atmel_tsadcc_write(ATMEL_TSADCC_IDR,
+				   ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
+		atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);
+
+		input_report_key(input_dev, BTN_TOUCH, 0);
+		input_sync(input_dev);
+
+	} else if (status & ATMEL_TSADCC_PENCNT) {
+		/* Pen detected */
+		reg = atmel_tsadcc_read(ATMEL_TSADCC_MR);
+		reg &= ~ATMEL_TSADCC_PENDBC;
+
+		atmel_tsadcc_write(ATMEL_TSADCC_IDR, ATMEL_TSADCC_PENCNT);
+		atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
+		atmel_tsadcc_write(ATMEL_TSADCC_IER,
+				   ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
+		atmel_tsadcc_write(ATMEL_TSADCC_TRGR,
+				   ATMEL_TSADCC_TRGMOD_PERIOD | (0x0FFF << 16));
+
+	} else if (status & ATMEL_TSADCC_EOC(3)) {
+		/* Conversion finished */
+
+		absx = atmel_tsadcc_read(ATMEL_TSADCC_CDR3) << 10;
+		absx /= atmel_tsadcc_read(ATMEL_TSADCC_CDR2);
+
+		absy = atmel_tsadcc_read(ATMEL_TSADCC_CDR1) << 10;
+		absy /= atmel_tsadcc_read(ATMEL_TSADCC_CDR0);
+
+		input_report_abs(input_dev, ABS_X, absx);
+		input_report_abs(input_dev, ABS_Y, absy);
+		input_report_key(input_dev, BTN_TOUCH, 1);
+		input_sync(input_dev);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * The functions for inserting/removing us as a module.
+ */
+
+static int __devinit atmel_tsadcc_probe(struct platform_device *pdev)
+{
+	struct atmel_tsadcc	*ts_dev;
+	struct input_dev	*input_dev;
+	struct resource		*res;
+	int		err = 0;
+	unsigned int	prsc;
+	unsigned int	reg;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "no mmio resource defined.\n");
+		return -ENXIO;
+	}
+
+	/* Allocate memory for device */
+	ts_dev = kzalloc(sizeof(struct atmel_tsadcc), GFP_KERNEL);
+	if (!ts_dev) {
+		dev_err(&pdev->dev, "failed to allocate memory.\n");
+		return -ENOMEM;
+	}
+	platform_set_drvdata(pdev, ts_dev);
+
+	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->irq = platform_get_irq(pdev, 0);
+	if (ts_dev->irq < 0) {
+		dev_err(&pdev->dev, "no irq ID is designated.\n");
+		err = -ENODEV;
+		goto err_free_dev;
+	}
+
+	if (!request_mem_region(res->start, res->end - res->start + 1,
+				"atmel tsadcc regs")) {
+		dev_err(&pdev->dev, "resources is unavailable.\n");
+		err = -EBUSY;
+		goto err_free_dev;
+	}
+
+	tsc_base = ioremap(res->start, res->end - res->start + 1);
+	if (!tsc_base) {
+		dev_err(&pdev->dev, "failed to map registers.\n");
+		err = -ENOMEM;
+		goto err_release_mem;
+	}
+
+	err = request_irq(ts_dev->irq, atmel_tsadcc_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;
+	}
+
+	ts_dev->input = input_dev;
+
+	snprintf(ts_dev->phys, sizeof(ts_dev->phys),
+		 "%s/input0", pdev->dev.bus_id);
+
+	input_dev->name = "atmel touch screen controller";
+	input_dev->phys = ts_dev->phys;
+	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, 0x3FF, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, 0x3FF, 0, 0);
+
+	/* clk_enable() always returns 0, no need to check it */
+	clk_enable(ts_dev->clk);
+
+	prsc = clk_get_rate(ts_dev->clk);
+	dev_info(&pdev->dev, "Master clock is set at: %d Hz\n", prsc);
+
+	prsc = prsc / ADC_CLOCK / 2 - 1;
+
+	reg = ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE		|
+		((0x00 << 5) & ATMEL_TSADCC_SLEEP)	|	/* Normal Mode */
+		((0x01 << 6) & ATMEL_TSADCC_PENDET)	|	/* Enable Pen Detect */
+		((prsc << 8) & ATMEL_TSADCC_PRESCAL)	|	/* PRESCAL */
+		((0x13 << 16) & ATMEL_TSADCC_STARTUP)	|	/* STARTUP */
+		((0x0F << 28) & ATMEL_TSADCC_PENDBC);		/* PENDBC */
+
+	atmel_tsadcc_write(ATMEL_TSADCC_CR, ATMEL_TSADCC_SWRST);
+	atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
+	atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
+	atmel_tsadcc_write(ATMEL_TSADCC_TSR, (0x3 << 24) & ATMEL_TSADCC_TSSHTIM);
+
+	atmel_tsadcc_read(ATMEL_TSADCC_SR);
+	atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);
+
+	/* All went ok, so 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(tsc_base);
+err_release_mem:
+	release_mem_region(res->start, res->end - res->start + 1);
+err_free_dev:
+	input_free_device(ts_dev->input);
+err_free_mem:
+	kfree(ts_dev);
+	return err;
+}
+
+static int __devexit atmel_tsadcc_remove(struct platform_device *pdev)
+{
+	struct atmel_tsadcc *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(tsc_base);
+	release_mem_region(res->start, res->end - res->start + 1);
+
+	clk_disable(ts_dev->clk);
+	clk_put(ts_dev->clk);
+
+	kfree(ts_dev);
+
+	return 0;
+}
+
+static struct platform_driver atmel_tsadcc_driver = {
+	.probe		= atmel_tsadcc_probe,
+	.remove		= __devexit_p(atmel_tsadcc_remove),
+	.driver		= {
+		.name	= "atmel_tsadcc",
+	},
+};
+
+static int __init atmel_tsadcc_init(void)
+{
+	return platform_driver_register(&atmel_tsadcc_driver);
+}
+
+static void __exit atmel_tsadcc_exit(void)
+{
+	platform_driver_unregister(&atmel_tsadcc_driver);
+}
+
+module_init(atmel_tsadcc_init);
+module_exit(atmel_tsadcc_exit);
+
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Atmel TouchScreen Driver");
+MODULE_AUTHOR("Dan Liang <[e-mail]>");
+