drivers/input/touchscreen/imx6ul_tsc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 //
 // Freescale i.MX6UL touchscreen controller driver
 //
 // Copyright (C) 2015 Freescale Semiconductor, Inc.

 #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>
 #include <linux/log2.h>

 /* ADC configuration registers field define */
 #define ADC_AIEN		(0x1 << 7)
 #define ADC_CONV_DISABLE	0x1F
 #define ADC_AVGE		(0x1 << 5)
 #define ADC_CAL			(0x1 << 7)
 #define ADC_CALF		0x2
 #define ADC_12BIT_MODE		(0x2 << 2)
 #define ADC_CONV_MODE_MASK	(0x3 << 2)
 #define ADC_IPG_CLK		0x00
 #define ADC_INPUT_CLK_MASK	0x3
 #define ADC_CLK_DIV_8		(0x03 << 5)
 #define ADC_CLK_DIV_MASK	(0x3 << 5)
 #define ADC_SHORT_SAMPLE_MODE	(0x0 << 4)
 #define ADC_SAMPLE_MODE_MASK	(0x1 << 4)
 #define ADC_HARDWARE_TRIGGER	(0x1 << 13)
 #define ADC_AVGS_SHIFT		14
 #define ADC_AVGS_MASK		(0x3 << 14)
 #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;

 	u32 measure_delay_time;
 	u32 pre_charge_time;
 	bool average_enable;
 	u32 average_select;

 	struct completion completion;
 };

 /*
  * TSC module need ADC to get the measure value. So
  * before config TSC, we should initialize ADC module.
  */
 static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
 {
 	u32 adc_hc = 0;
 	u32 adc_gc;
 	u32 adc_gs;
 	u32 adc_cfg;
 	unsigned long timeout;

 	reinit_completion(&tsc->completion);

 	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
 	adc_cfg &= ~(ADC_CONV_MODE_MASK | ADC_INPUT_CLK_MASK);
 	adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;
 	adc_cfg &= ~(ADC_CLK_DIV_MASK | ADC_SAMPLE_MODE_MASK);
 	adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;
 	if (tsc->average_enable) {
 		adc_cfg &= ~ADC_AVGS_MASK;
 		adc_cfg |= (tsc->average_select) << ADC_AVGS_SHIFT;
 	}
 	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;
 	if (tsc->average_enable)
 		adc_gc |= ADC_AVGE;
 	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");
 		return -ETIMEDOUT;
 	}

 	adc_gs = readl(tsc->adc_regs + REG_ADC_GS);
 	if (adc_gs & ADC_CALF) {
 		dev_err(tsc->dev, "ADC calibration failed\n");
 		return -EINVAL;
 	}

 	/* 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);

 	return 0;
 }

 /*
  * 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)
 {
 	u32 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)
 {
 	u32 basic_setting = 0;
 	u32 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 int imx6ul_tsc_init(struct imx6ul_tsc *tsc)
 {
 	int err;

 	err = imx6ul_adc_init(tsc);
 	if (err)
 		return err;
 	imx6ul_tsc_channel_config(tsc);
 	imx6ul_tsc_set(tsc);

 	return 0;
 }

 static void imx6ul_tsc_disable(struct imx6ul_tsc *tsc)
 {
 	u32 tsc_flow;
 	u32 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);
 	u32 state_machine;
 	u32 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;
 	u32 status;
 	u32 value;
 	u32 x, y;
 	u32 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;
 	u32 coco;

 	coco = readl(tsc->adc_regs + REG_ADC_HS);
 	if (coco & 0x01) {
 		readl(tsc->adc_regs + REG_ADC_R0);
 		complete(&tsc->completion);
 	}

 	return IRQ_HANDLED;
 }

 static int imx6ul_tsc_start(struct imx6ul_tsc *tsc)
 {
 	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);
 		goto disable_adc_clk;
 	}

 	err = imx6ul_tsc_init(tsc);
 	if (err)
 		goto disable_tsc_clk;

 	return 0;

 disable_tsc_clk:
 	clk_disable_unprepare(tsc->tsc_clk);
 disable_adc_clk:
 	clk_disable_unprepare(tsc->adc_clk);
 	return err;
 }

 static void imx6ul_tsc_stop(struct imx6ul_tsc *tsc)
 {
 	imx6ul_tsc_disable(tsc);

 	clk_disable_unprepare(tsc->tsc_clk);
 	clk_disable_unprepare(tsc->adc_clk);
 }


 static int imx6ul_tsc_open(struct input_dev *input_dev)
 {
 	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);

 	return imx6ul_tsc_start(tsc);
 }

 static void imx6ul_tsc_close(struct input_dev *input_dev)
 {
 	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);

 	imx6ul_tsc_stop(tsc);
 }

 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;
 	int err;
 	int tsc_irq;
 	int adc_irq;
 	u32 average_samples;

 	tsc = devm_kzalloc(&pdev->dev, sizeof(*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->tsc_regs = devm_platform_ioremap_resource(pdev, 0);
 	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;
 	}

 	tsc->adc_regs = devm_platform_ioremap_resource(pdev, 1);
 	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)
 		return tsc_irq;

 	adc_irq = platform_get_irq(pdev, 1);
 	if (adc_irq < 0)
 		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 = of_property_read_u32(np, "touchscreen-average-samples",
 				   &average_samples);
 	if (err)
 		average_samples = 1;

 	switch (average_samples) {
 	case 1:
 		tsc->average_enable = false;
 		tsc->average_select = 0; /* value unused; initialize anyway */
 		break;
 	case 4:
 	case 8:
 	case 16:
 	case 32:
 		tsc->average_enable = true;
 		tsc->average_select = ilog2(average_samples) - 2;
 		break;
 	default:
 		dev_err(&pdev->dev,
 			"touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
 			average_samples);
 		return -EINVAL;
 	}

 	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_device_enabled(input_dev))
 		imx6ul_tsc_stop(tsc);

 	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_device_enabled(input_dev))
 		retval = imx6ul_tsc_start(tsc);

 	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");
	// SPDX-License-Identifier: GPL-2.0
	//
	// Freescale i.MX6UL touchscreen controller driver
	//
	// Copyright (C) 2015 Freescale Semiconductor, Inc.

	#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>
	#include <linux/log2.h>

	/* ADC configuration registers field define */
	#define ADC_AIEN (0x1 << 7)
	#define ADC_CONV_DISABLE 0x1F
	#define ADC_AVGE (0x1 << 5)
	#define ADC_CAL (0x1 << 7)
	#define ADC_CALF 0x2
	#define ADC_12BIT_MODE (0x2 << 2)
	#define ADC_CONV_MODE_MASK (0x3 << 2)
	#define ADC_IPG_CLK 0x00
	#define ADC_INPUT_CLK_MASK 0x3
	#define ADC_CLK_DIV_8 (0x03 << 5)
	#define ADC_CLK_DIV_MASK (0x3 << 5)
	#define ADC_SHORT_SAMPLE_MODE (0x0 << 4)
	#define ADC_SAMPLE_MODE_MASK (0x1 << 4)
	#define ADC_HARDWARE_TRIGGER (0x1 << 13)
	#define ADC_AVGS_SHIFT 14
	#define ADC_AVGS_MASK (0x3 << 14)
	#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;

	u32 measure_delay_time;
	u32 pre_charge_time;
	bool average_enable;
	u32 average_select;

	struct completion completion;
	};

	/*
	* TSC module need ADC to get the measure value. So
	* before config TSC, we should initialize ADC module.
	*/
	static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
	{
	u32 adc_hc = 0;
	u32 adc_gc;
	u32 adc_gs;
	u32 adc_cfg;
	unsigned long timeout;

	reinit_completion(&tsc->completion);

	adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
	adc_cfg &= ~(ADC_CONV_MODE_MASK \| ADC_INPUT_CLK_MASK);
	adc_cfg \|= ADC_12BIT_MODE \| ADC_IPG_CLK;
	adc_cfg &= ~(ADC_CLK_DIV_MASK \| ADC_SAMPLE_MODE_MASK);
	adc_cfg \|= ADC_CLK_DIV_8 \| ADC_SHORT_SAMPLE_MODE;
	if (tsc->average_enable) {
	adc_cfg &= ~ADC_AVGS_MASK;
	adc_cfg \|= (tsc->average_select) << ADC_AVGS_SHIFT;
	}
	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;
	if (tsc->average_enable)
	adc_gc \|= ADC_AVGE;
	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");
	return -ETIMEDOUT;
	}

	adc_gs = readl(tsc->adc_regs + REG_ADC_GS);
	if (adc_gs & ADC_CALF) {
	dev_err(tsc->dev, "ADC calibration failed\n");
	return -EINVAL;
	}

	/* 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);

	return 0;
	}

	/*
	* 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)
	{
	u32 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)
	{
	u32 basic_setting = 0;
	u32 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 int imx6ul_tsc_init(struct imx6ul_tsc *tsc)
	{
	int err;

	err = imx6ul_adc_init(tsc);
	if (err)
	return err;
	imx6ul_tsc_channel_config(tsc);
	imx6ul_tsc_set(tsc);

	return 0;
	}

	static void imx6ul_tsc_disable(struct imx6ul_tsc *tsc)
	{
	u32 tsc_flow;
	u32 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);
	u32 state_machine;
	u32 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;
	u32 status;
	u32 value;
	u32 x, y;
	u32 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;
	u32 coco;

	coco = readl(tsc->adc_regs + REG_ADC_HS);
	if (coco & 0x01) {
	readl(tsc->adc_regs + REG_ADC_R0);
	complete(&tsc->completion);
	}

	return IRQ_HANDLED;
	}

	static int imx6ul_tsc_start(struct imx6ul_tsc *tsc)
	{
	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);
	goto disable_adc_clk;
	}

	err = imx6ul_tsc_init(tsc);
	if (err)
	goto disable_tsc_clk;

	return 0;

	disable_tsc_clk:
	clk_disable_unprepare(tsc->tsc_clk);
	disable_adc_clk:
	clk_disable_unprepare(tsc->adc_clk);
	return err;
	}

	static void imx6ul_tsc_stop(struct imx6ul_tsc *tsc)
	{
	imx6ul_tsc_disable(tsc);

	clk_disable_unprepare(tsc->tsc_clk);
	clk_disable_unprepare(tsc->adc_clk);
	}


	static int imx6ul_tsc_open(struct input_dev *input_dev)
	{
	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);

	return imx6ul_tsc_start(tsc);
	}

	static void imx6ul_tsc_close(struct input_dev *input_dev)
	{
	struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);

	imx6ul_tsc_stop(tsc);
	}

	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;
	int err;
	int tsc_irq;
	int adc_irq;
	u32 average_samples;

	tsc = devm_kzalloc(&pdev->dev, sizeof(*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->tsc_regs = devm_platform_ioremap_resource(pdev, 0);
	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;
	}

	tsc->adc_regs = devm_platform_ioremap_resource(pdev, 1);
	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)
	return tsc_irq;

	adc_irq = platform_get_irq(pdev, 1);
	if (adc_irq < 0)
	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 = of_property_read_u32(np, "touchscreen-average-samples",
	&average_samples);
	if (err)
	average_samples = 1;

	switch (average_samples) {
	case 1:
	tsc->average_enable = false;
	tsc->average_select = 0; /* value unused; initialize anyway */
	break;
	case 4:
	case 8:
	case 16:
	case 32:
	tsc->average_enable = true;
	tsc->average_select = ilog2(average_samples) - 2;
	break;
	default:
	dev_err(&pdev->dev,
	"touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
	average_samples);
	return -EINVAL;
	}

	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_device_enabled(input_dev))
	imx6ul_tsc_stop(tsc);

	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_device_enabled(input_dev))
	retval = imx6ul_tsc_start(tsc);

	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");