Input: touchscreen - add imx6ul_tsc driver support

* Freescale i.MX6UL Touch Controller

Required properties:

- compatible: must be "fsl,imx6ul-tsc".

- reg: this touch controller address and the ADC2 address.

- interrupts: the interrupt of this touch controller and ADC2.

- clocks: the root clock of touch controller and ADC2.

- clock-names; must be "tsc" and "adc".

- xnur-gpio: the X- gpio this controller connect to.

  This xnur-gpio returns to low once the finger leave the touch screen (The

  last touch event the touch controller capture).

Optional properties:

- measure-delay-time: the value of measure delay time.

  Before X-axis or Y-axis measurement, the screen need some time before

  even potential distribution ready.

  This value depends on the touch screen.

- pre-charge-time: the touch screen need some time to precharge.

  This value depends on the touch screen.

Example:

	tsc: tsc@02040000 {

		compatible = "fsl,imx6ul-tsc";

		reg = <0x02040000 0x4000>, <0x0219c000 0x4000>;

		interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>,

			     <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>;

		clocks = <&clks IMX6UL_CLK_IPG>,

			 <&clks IMX6UL_CLK_ADC2>;

		clock-names = "tsc", "adc";

		pinctrl-names = "default";

		pinctrl-0 = <&pinctrl_tsc>;

		xnur-gpio = <&gpio1 3 GPIO_ACTIVE_LOW>;

		measure-delay-time = <0xfff>;

		pre-charge-time = <0xffff>;

		status = "okay";

	};

	  To compile this driver as a module, choose M here: the

	  module will be called mtouch.

config TOUCHSCREEN_IMX6UL_TSC

	tristate "Freescale i.MX6UL touchscreen controller"

	depends on (OF && GPIOLIB) || COMPILE_TEST

	help

	  Say Y here if you have a Freescale i.MX6UL, and want to

	  use the internal touchscreen controller.

	  If unsure, say N.

	  To compile this driver as a module, choose M here: the

	  module will be called imx6ul_tsc.

config TOUCHSCREEN_INEXIO

	tristate "iNexio serial touchscreens"

	select SERIO

obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o

obj-$(CONFIG_TOUCHSCREEN_GOODIX)	+= goodix.o

obj-$(CONFIG_TOUCHSCREEN_ILI210X)	+= ili210x.o

obj-$(CONFIG_TOUCHSCREEN_IMX6UL_TSC)	+= imx6ul_tsc.o

obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o

obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o

obj-$(CONFIG_TOUCHSCREEN_IPROC)		+= bcm_iproc_tsc.o

/*

 * Freescale i.MX6UL touchscreen controller driver

 *

 * Copyright (C) 2015 Freescale Semiconductor, Inc.

 *

 * 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/errno.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/gpio/consumer.h>

#include <linux/input.h>

#include <linux/slab.h>

#include <linux/completion.h>

#include <linux/delay.h>

#include <linux/of.h>

#include <linux/interrupt.h>

#include <linux/platform_device.h>

#include <linux/clk.h>

#include <linux/io.h>

/* ADC configuration registers field define */

#define ADC_AIEN		(0x1 << 7)

#define ADC_CONV_DISABLE	0x1F

#define ADC_CAL			(0x1 << 7)

#define ADC_CALF		0x2

#define ADC_12BIT_MODE		(0x2 << 2)

#define ADC_IPG_CLK		0x00

#define ADC_CLK_DIV_8		(0x03 << 5)

#define ADC_SHORT_SAMPLE_MODE	(0x0 << 4)

#define ADC_HARDWARE_TRIGGER	(0x1 << 13)

#define SELECT_CHANNEL_4	0x04

#define SELECT_CHANNEL_1	0x01

#define DISABLE_CONVERSION_INT	(0x0 << 7)

/* ADC registers */

#define REG_ADC_HC0		0x00

#define REG_ADC_HC1		0x04

#define REG_ADC_HC2		0x08

#define REG_ADC_HC3		0x0C

#define REG_ADC_HC4		0x10

#define REG_ADC_HS		0x14

#define REG_ADC_R0		0x18

#define REG_ADC_CFG		0x2C

#define REG_ADC_GC		0x30

#define REG_ADC_GS		0x34

#define ADC_TIMEOUT		msecs_to_jiffies(100)

/* TSC registers */

#define REG_TSC_BASIC_SETING	0x00

#define REG_TSC_PRE_CHARGE_TIME	0x10

#define REG_TSC_FLOW_CONTROL	0x20

#define REG_TSC_MEASURE_VALUE	0x30

#define REG_TSC_INT_EN		0x40

#define REG_TSC_INT_SIG_EN	0x50

#define REG_TSC_INT_STATUS	0x60

#define REG_TSC_DEBUG_MODE	0x70

#define REG_TSC_DEBUG_MODE2	0x80

/* TSC configuration registers field define */

#define DETECT_4_WIRE_MODE	(0x0 << 4)

#define AUTO_MEASURE		0x1

#define MEASURE_SIGNAL		0x1

#define DETECT_SIGNAL		(0x1 << 4)

#define VALID_SIGNAL		(0x1 << 8)

#define MEASURE_INT_EN		0x1

#define MEASURE_SIG_EN		0x1

#define VALID_SIG_EN		(0x1 << 8)

#define DE_GLITCH_2		(0x2 << 29)

#define START_SENSE		(0x1 << 12)

#define TSC_DISABLE		(0x1 << 16)

#define DETECT_MODE		0x2

struct imx6ul_tsc {

	struct device *dev;

	struct input_dev *input;

	void __iomem *tsc_regs;

	void __iomem *adc_regs;

	struct clk *tsc_clk;

	struct clk *adc_clk;

	struct gpio_desc *xnur_gpio;

	int measure_delay_time;

	int pre_charge_time;

	struct completion completion;

};

/*

 * TSC module need ADC to get the measure value. So

 * before config TSC, we should initialize ADC module.

 */

static void imx6ul_adc_init(struct imx6ul_tsc *tsc)

{

	int adc_hc = 0;

	int adc_gc;

	int adc_gs;

	int adc_cfg;

	int timeout;

	reinit_completion(&tsc->completion);

	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);

	adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;

	adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;

	adc_cfg &= ~ADC_HARDWARE_TRIGGER;

	writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);

	/* enable calibration interrupt */

	adc_hc |= ADC_AIEN;

	adc_hc |= ADC_CONV_DISABLE;

	writel(adc_hc, tsc->adc_regs + REG_ADC_HC0);

	/* start ADC calibration */

	adc_gc = readl(tsc->adc_regs + REG_ADC_GC);

	adc_gc |= ADC_CAL;

	writel(adc_gc, tsc->adc_regs + REG_ADC_GC);

	timeout = wait_for_completion_timeout

			(&tsc->completion, ADC_TIMEOUT);

	if (timeout == 0)

		dev_err(tsc->dev, "Timeout for adc calibration\n");

	adc_gs = readl(tsc->adc_regs + REG_ADC_GS);

	if (adc_gs & ADC_CALF)

		dev_err(tsc->dev, "ADC calibration failed\n");

	/* TSC need the ADC work in hardware trigger */

	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);

	adc_cfg |= ADC_HARDWARE_TRIGGER;

	writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);

}

/*

 * This is a TSC workaround. Currently TSC misconnect two

 * ADC channels, this function remap channel configure for

 * hardware trigger.

 */

static void imx6ul_tsc_channel_config(struct imx6ul_tsc *tsc)

{

	int adc_hc0, adc_hc1, adc_hc2, adc_hc3, adc_hc4;

	adc_hc0 = DISABLE_CONVERSION_INT;

	writel(adc_hc0, tsc->adc_regs + REG_ADC_HC0);

	adc_hc1 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_4;

	writel(adc_hc1, tsc->adc_regs + REG_ADC_HC1);

	adc_hc2 = DISABLE_CONVERSION_INT;

	writel(adc_hc2, tsc->adc_regs + REG_ADC_HC2);

	adc_hc3 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_1;

	writel(adc_hc3, tsc->adc_regs + REG_ADC_HC3);

	adc_hc4 = DISABLE_CONVERSION_INT;

	writel(adc_hc4, tsc->adc_regs + REG_ADC_HC4);

}

/*

 * TSC setting, confige the pre-charge time and measure delay time.

 * different touch screen may need different pre-charge time and

 * measure delay time.

 */

static void imx6ul_tsc_set(struct imx6ul_tsc *tsc)

{

	int basic_setting = 0;

	int start;

	basic_setting |= tsc->measure_delay_time << 8;

	basic_setting |= DETECT_4_WIRE_MODE | AUTO_MEASURE;

	writel(basic_setting, tsc->tsc_regs + REG_TSC_BASIC_SETING);

	writel(DE_GLITCH_2, tsc->tsc_regs + REG_TSC_DEBUG_MODE2);

	writel(tsc->pre_charge_time, tsc->tsc_regs + REG_TSC_PRE_CHARGE_TIME);

	writel(MEASURE_INT_EN, tsc->tsc_regs + REG_TSC_INT_EN);

	writel(MEASURE_SIG_EN | VALID_SIG_EN,

		tsc->tsc_regs + REG_TSC_INT_SIG_EN);

	/* start sense detection */

	start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);

	start |= START_SENSE;

	start &= ~TSC_DISABLE;

	writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);

}

static void imx6ul_tsc_init(struct imx6ul_tsc *tsc)

{

	imx6ul_adc_init(tsc);

	imx6ul_tsc_channel_config(tsc);

	imx6ul_tsc_set(tsc);

}

static void imx6ul_tsc_disable(struct imx6ul_tsc *tsc)

{

	int tsc_flow;

	int adc_cfg;

	/* TSC controller enters to idle status */

	tsc_flow = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);

	tsc_flow |= TSC_DISABLE;

	writel(tsc_flow, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);

	/* ADC controller enters to stop mode */

	adc_cfg = readl(tsc->adc_regs + REG_ADC_HC0);

	adc_cfg |= ADC_CONV_DISABLE;

	writel(adc_cfg, tsc->adc_regs + REG_ADC_HC0);

}

/* Delay some time (max 2ms), wait the pre-charge done. */

static bool tsc_wait_detect_mode(struct imx6ul_tsc *tsc)

{

	unsigned long timeout = jiffies + msecs_to_jiffies(2);

	int state_machine;

	int debug_mode2;

	do {

		if (time_after(jiffies, timeout))

			return false;

		usleep_range(200, 400);

		debug_mode2 = readl(tsc->tsc_regs + REG_TSC_DEBUG_MODE2);

		state_machine = (debug_mode2 >> 20) & 0x7;

	} while (state_machine != DETECT_MODE);

	usleep_range(200, 400);

	return true;

}

static irqreturn_t tsc_irq_fn(int irq, void *dev_id)

{

	struct imx6ul_tsc *tsc = dev_id;

	int status;

	int value;

	int x, y;

	int start;

	status = readl(tsc->tsc_regs + REG_TSC_INT_STATUS);

	/* write 1 to clear the bit measure-signal */

	writel(MEASURE_SIGNAL | DETECT_SIGNAL,

		tsc->tsc_regs + REG_TSC_INT_STATUS);

	/* It's a HW self-clean bit. Set this bit and start sense detection */

	start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);

	start |= START_SENSE;

	writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);

	if (status & MEASURE_SIGNAL) {

		value = readl(tsc->tsc_regs + REG_TSC_MEASURE_VALUE);

		x = (value >> 16) & 0x0fff;

		y = value & 0x0fff;

		/*

		 * In detect mode, we can get the xnur gpio value,

		 * otherwise assume contact is stiull active.

		 */

		if (!tsc_wait_detect_mode(tsc) ||

		    gpiod_get_value_cansleep(tsc->xnur_gpio)) {

			input_report_key(tsc->input, BTN_TOUCH, 1);

			input_report_abs(tsc->input, ABS_X, x);

			input_report_abs(tsc->input, ABS_Y, y);

		} else {

			input_report_key(tsc->input, BTN_TOUCH, 0);

		}

		input_sync(tsc->input);

	}

	return IRQ_HANDLED;

}

static irqreturn_t adc_irq_fn(int irq, void *dev_id)

{

	struct imx6ul_tsc *tsc = dev_id;

	int coco;

	int value;

	coco = readl(tsc->adc_regs + REG_ADC_HS);

	if (coco & 0x01) {

		value = readl(tsc->adc_regs + REG_ADC_R0);

		complete(&tsc->completion);

	}

	return IRQ_HANDLED;

}

static int imx6ul_tsc_open(struct input_dev *input_dev)

{

	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);

	int err;

	err = clk_prepare_enable(tsc->adc_clk);

	if (err) {

		dev_err(tsc->dev,

			"Could not prepare or enable the adc clock: %d\n",

			err);

		return err;

	}

	err = clk_prepare_enable(tsc->tsc_clk);

	if (err) {

		dev_err(tsc->dev,

			"Could not prepare or enable the tsc clock: %d\n",

			err);

		clk_disable_unprepare(tsc->adc_clk);

		return err;

	}

	imx6ul_tsc_init(tsc);

	return 0;

}

static void imx6ul_tsc_close(struct input_dev *input_dev)

{

	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);

	imx6ul_tsc_disable(tsc);

	clk_disable_unprepare(tsc->tsc_clk);

	clk_disable_unprepare(tsc->adc_clk);

}

static int imx6ul_tsc_probe(struct platform_device *pdev)

{

	struct device_node *np = pdev->dev.of_node;

	struct imx6ul_tsc *tsc;

	struct input_dev *input_dev;

	struct resource *tsc_mem;

	struct resource *adc_mem;

	int err;

	int tsc_irq;

	int adc_irq;

	tsc = devm_kzalloc(&pdev->dev, sizeof(struct imx6ul_tsc), GFP_KERNEL);

	if (!tsc)

		return -ENOMEM;

	input_dev = devm_input_allocate_device(&pdev->dev);

	if (!input_dev)

		return -ENOMEM;

	input_dev->name = "iMX6UL TouchScreen Controller";

	input_dev->id.bustype = BUS_HOST;

	input_dev->open = imx6ul_tsc_open;

	input_dev->close = imx6ul_tsc_close;

	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);

	input_set_abs_params(input_dev, ABS_X, 0, 0xFFF, 0, 0);

	input_set_abs_params(input_dev, ABS_Y, 0, 0xFFF, 0, 0);

	input_set_drvdata(input_dev, tsc);

	tsc->dev = &pdev->dev;

	tsc->input = input_dev;

	init_completion(&tsc->completion);

	tsc->xnur_gpio = devm_gpiod_get(&pdev->dev, "xnur", GPIOD_IN);

	if (IS_ERR(tsc->xnur_gpio)) {

		err = PTR_ERR(tsc->xnur_gpio);

		dev_err(&pdev->dev,

			"failed to request GPIO tsc_X- (xnur): %d\n", err);

		return err;

	}

	tsc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	tsc->tsc_regs = devm_ioremap_resource(&pdev->dev, tsc_mem);

	if (IS_ERR(tsc->tsc_regs)) {

		err = PTR_ERR(tsc->tsc_regs);

		dev_err(&pdev->dev, "failed to remap tsc memory: %d\n", err);

		return err;

	}

	adc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);

	tsc->adc_regs = devm_ioremap_resource(&pdev->dev, adc_mem);

	if (IS_ERR(tsc->adc_regs)) {

		err = PTR_ERR(tsc->adc_regs);

		dev_err(&pdev->dev, "failed to remap adc memory: %d\n", err);

		return err;

	}

	tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");

	if (IS_ERR(tsc->tsc_clk)) {

		err = PTR_ERR(tsc->tsc_clk);

		dev_err(&pdev->dev, "failed getting tsc clock: %d\n", err);

		return err;

	}

	tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");

	if (IS_ERR(tsc->adc_clk)) {

		err = PTR_ERR(tsc->adc_clk);

		dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);

		return err;

	}

	tsc_irq = platform_get_irq(pdev, 0);

	if (tsc_irq < 0) {

		dev_err(&pdev->dev, "no tsc irq resource?\n");

		return tsc_irq;

	}

	adc_irq = platform_get_irq(pdev, 1);

	if (adc_irq <= 0) {

		dev_err(&pdev->dev, "no adc irq resource?\n");

		return adc_irq;

	}

	err = devm_request_threaded_irq(tsc->dev, tsc_irq,

					NULL, tsc_irq_fn, IRQF_ONESHOT,

					dev_name(&pdev->dev), tsc);

	if (err) {

		dev_err(&pdev->dev,

			"failed requesting tsc irq %d: %d\n",

			tsc_irq, err);

		return err;

	}

	err = devm_request_irq(tsc->dev, adc_irq, adc_irq_fn, 0,

				dev_name(&pdev->dev), tsc);

	if (err) {

		dev_err(&pdev->dev,

			"failed requesting adc irq %d: %d\n",

			adc_irq, err);

		return err;

	}

	err = of_property_read_u32(np, "measure-delay-time",

				   &tsc->measure_delay_time);

	if (err)

		tsc->measure_delay_time = 0xffff;

	err = of_property_read_u32(np, "pre-charge-time",

				   &tsc->pre_charge_time);

	if (err)

		tsc->pre_charge_time = 0xfff;

	err = input_register_device(tsc->input);

	if (err) {

		dev_err(&pdev->dev,

			"failed to register input device: %d\n", err);

		return err;

	}

	platform_set_drvdata(pdev, tsc);

	return 0;

}

static int __maybe_unused imx6ul_tsc_suspend(struct device *dev)

{

	struct platform_device *pdev = to_platform_device(dev);

	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);

	struct input_dev *input_dev = tsc->input;

	mutex_lock(&input_dev->mutex);

	if (input_dev->users) {

		imx6ul_tsc_disable(tsc);

		clk_disable_unprepare(tsc->tsc_clk);

		clk_disable_unprepare(tsc->adc_clk);

	}

	mutex_unlock(&input_dev->mutex);

	return 0;

}

static int __maybe_unused imx6ul_tsc_resume(struct device *dev)

{

	struct platform_device *pdev = to_platform_device(dev);

	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);

	struct input_dev *input_dev = tsc->input;

	int retval = 0;

	mutex_lock(&input_dev->mutex);

	if (input_dev->users) {

		retval = clk_prepare_enable(tsc->adc_clk);

		if (retval)

			goto out;

		retval = clk_prepare_enable(tsc->tsc_clk);

		if (retval) {

			clk_disable_unprepare(tsc->adc_clk);

			goto out;

		}

		imx6ul_tsc_init(tsc);

	}

out:

	mutex_unlock(&input_dev->mutex);

	return retval;

}

static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,

			 imx6ul_tsc_suspend, imx6ul_tsc_resume);

static const struct of_device_id imx6ul_tsc_match[] = {

	{ .compatible = "fsl,imx6ul-tsc", },

	{ /* sentinel */ }

};

MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);

static struct platform_driver imx6ul_tsc_driver = {

	.driver		= {

		.name	= "imx6ul-tsc",

		.of_match_table	= imx6ul_tsc_match,

		.pm	= &imx6ul_tsc_pm_ops,

	},

	.probe		= imx6ul_tsc_probe,

};

module_platform_driver(imx6ul_tsc_driver);

MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");

MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");

MODULE_LICENSE("GPL v2");