Hi Haibo,

On Tue, Jul 28, 2015 at 05:58:37PM +0800, Haibo Chen wrote:

Freescale i.MX6UL contains a internal touchscreen controller,
this patch add a driver to support this controller.

This looks pretty reasonable; just a few comments below.

I do not think you need of_irq and of_device.

+#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;
+
+	int 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;
+
+	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);
+

Since this is called on every resume you need to reinit completion;
probably at the beginning of this function.

+	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 irqreturn_t tsc_irq_fn(int irq, void *dev_id)
+{
+	struct imx6ul_tsc *tsc = (struct imx6ul_tsc *)dev_id;

No need to cast void pointers.

+	int status;
+	int value;
+	int x, y;
+	int xnur;
+	int debug_mode2;
+	int state_machine;
+	int start;
+	unsigned long timeout;
+
+	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;
+
+		/*
+		 * Delay some time(max 2ms), wait the pre-charge done.
+		 * After the pre-change mode, TSC go into detect mode.
+		 * And in detect mode, we can get the xnur gpio value.
+		 * If xnur is low, this means the touch screen still
+		 * be touched. If xnur is high, this means finger leave
+		 * the touch screen.
+		 */
+		timeout = jiffies + HZ/500;
+		do {
+			if (time_after(jiffies, timeout)) {
+				xnur = 0;
+				goto touch_event;
+			}
+			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);
+
+		xnur = gpio_get_value(tsc->xnur_gpio);

It seems to me that this GPIO is actually active low: we reporting
active touch as long as we read 0.

+touch_event:
+		if (xnur == 0) {
+			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);

If one branch has braces all of them should have braces.

+
+		input_sync(tsc->input);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t adc_irq_fn(int irq, void *dev_id)
+{
+	struct imx6ul_tsc *tsc = (struct imx6ul_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 const struct of_device_id imx6ul_tsc_match[] = {
+	{ .compatible = "fsl,imx6ul-tsc", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
+
+static int imx6ul_tsc_probe(struct platform_device *pdev)
+{
+	struct imx6ul_tsc *tsc;
+	struct resource *tsc_mem;
+	struct resource *adc_mem;
+	struct input_dev *input_dev;
+	struct device_node *np = pdev->dev.of_node;
+	int err;
+	int tsc_irq;
+	int adc_irq;
+
+	tsc = devm_kzalloc(&pdev->dev, sizeof(struct imx6ul_tsc), GFP_KERNEL);
+	input_dev = devm_input_allocate_device(&pdev->dev);

Using devm does not mean you do not need to check results of memory
allocation.

+
+	tsc->dev = &pdev->dev;
+
+	tsc->input = input_dev;
+	tsc->input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	tsc->input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+	input_set_abs_params(tsc->input, ABS_X, 0, 0xFFF, 0, 0);
+	input_set_abs_params(tsc->input, ABS_Y, 0, 0xFFF, 0, 0);
+
+	tsc->input->name = "iMX6UL TouchScreen Controller";
+
+	tsc->xnur_gpio = of_get_named_gpio(np, "xnur-gpio", 0);
+	err = gpio_request_one(tsc->xnur_gpio, GPIOF_IN, "tsc_X-");

Why are you not using devm for gpio? Actually, why don't you also use
gpiod? As is you are leaking that gpio in all error paths below.

+	if (err) {
+		dev_err(&pdev->dev, "failed to request GPIO tsc_X-\n");
+		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)) {
+		dev_err(&pdev->dev, "failed to remap tsc memory\n");
+		err = PTR_ERR(tsc->tsc_regs);
+		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)) {
+		dev_err(&pdev->dev, "failed to remap adc memory\n");
+		err = PTR_ERR(tsc->adc_regs);
+		return err;
+	}
+
+	tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");
+	if (IS_ERR(tsc->tsc_clk)) {
+		dev_err(&pdev->dev, "failed getting tsc clock\n");
+		err = PTR_ERR(tsc->tsc_clk);
+		return err;
+	}
+
+	tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");
+	if (IS_ERR(tsc->adc_clk)) {
+		dev_err(&pdev->dev, "failed getting adc clock\n");
+		err = PTR_ERR(tsc->adc_clk);
+		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_TRIGGER_HIGH | IRQF_ONESHOT,
+					dev_name(&pdev->dev), tsc);
+	if (err < 0) {
+		dev_err(&pdev->dev,
+			"failed requesting tsc irq %d\n",
+					    tsc_irq);
+		return err;
+	}
+
+	err = devm_request_irq(tsc->dev, adc_irq,
+				adc_irq_fn, 0,
+				dev_name(&pdev->dev), tsc);
+	if (err < 0) {
+		dev_err(&pdev->dev,
+			"failed requesting adc irq %d\n",
+					    adc_irq);
+		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;
+
+	init_completion(&tsc->completion);
+
+	err = clk_prepare_enable(tsc->adc_clk);
+	if (err) {
+		dev_err(&pdev->dev,
+			"Could not prepare or enable the adc clock.\n");
+		return err;
+	}
+
+	err = clk_prepare_enable(tsc->tsc_clk);
+	if (err) {
+		dev_err(&pdev->dev,
+			"Could not prepare or enable the tsc clock.\n");
+		goto error_tsc_clk_enable;
+	}
+
+	err = input_register_device(tsc->input);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to register input device\n");
+		err = -EIO;
+		goto err_input_register;
+	}
+
+	imx6ul_tsc_init(tsc);

Enabling clock and initializing the controller is better in open()
method of input device. If you also implement close() you can get rid of
remove().

+
+	platform_set_drvdata(pdev, tsc);
+	return 0;
+
+err_input_register:
+	clk_disable_unprepare(tsc->tsc_clk);
+error_tsc_clk_enable:
+	clk_disable_unprepare(tsc->adc_clk);
+
+	return err;
+}
+
+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);
+}
+
+static int imx6ul_tsc_remove(struct platform_device *pdev)
+{
+	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
+
+	imx6ul_tsc_disable(tsc);
+
+	clk_disable_unprepare(tsc->tsc_clk);
+	clk_disable_unprepare(tsc->adc_clk);
+	input_unregister_device(tsc->input);
+	kfree(tsc);

Tsc is allocated with devm(), you can't kfree() it.

+
+	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);
+
+	imx6ul_tsc_disable(tsc);
+
+	clk_disable_unprepare(tsc->tsc_clk);
+	clk_disable_unprepare(tsc->adc_clk);
+
+	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);
+	int err;
+
+	err = clk_prepare_enable(tsc->adc_clk);
+	if (err)
+		return err;
+
+	err = clk_prepare_enable(tsc->tsc_clk);
+	if (err) {
+		clk_disable_unprepare(tsc->adc_clk);
+		return err;
+	}
+
+	imx6ul_tsc_init(tsc);
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
+			 imx6ul_tsc_suspend,
+			 imx6ul_tsc_resume);
+
+static struct platform_driver imx6ul_tsc_driver = {
+	.driver		= {
+		.name	= "imx6ul-tsc",
+		.owner	= THIS_MODULE,
+		.of_match_table	= imx6ul_tsc_match,
+		.pm	= &imx6ul_tsc_pm_ops,
+	},
+	.probe		= imx6ul_tsc_probe,
+	.remove		= imx6ul_tsc_remove,
+};
+module_platform_driver(imx6ul_tsc_driver);
+
+MODULE_AUTHOR("Haibo Chen [off-list ref]");
+MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

Can you try the patch below and let me know if it still works (you'll
need to adjust your DTS for xnur gpio being active low).

Thanks!

-- 
Dmitry

Input: imx6ul_tsc - misc changes

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 .../bindings/input/touchscreen/imx6ul_tsc.txt      |    2 
 drivers/input/touchscreen/Kconfig                  |    2 
 drivers/input/touchscreen/imx6ul_tsc.c             |  262 +++++++++++---------
 3 files changed, 143 insertions(+), 123 deletions(-)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt b/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
index ac41c32..c933588 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt

@@ -29,7 +29,7 @@ Example:
 		clock-names = "tsc", "adc";
 		pinctrl-names = "default";
 		pinctrl-0 = <&pinctrl_tsc>;
-		xnur-gpio = <&gpio1 3 GPIO_ACTIVE_HIGH>;
+		xnur-gpio = <&gpio1 3 GPIO_ACTIVE_LOW>;
 		measure-delay-time = <0xfff>;
 		pre-charge-time = <0xffff>;
 		status = "okay";

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 9a1a293..5ecf19b 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig

@@ -481,7 +481,7 @@ config TOUCHSCREEN_MTOUCH
 
 config TOUCHSCREEN_IMX6UL_TSC
 	tristate "Freescale i.MX6UL touchscreen controller"
-	depends on OF
+	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.

diff --git a/drivers/input/touchscreen/imx6ul_tsc.c b/drivers/input/touchscreen/imx6ul_tsc.c
index 807f1db..1d028ed 100644
--- a/drivers/input/touchscreen/imx6ul_tsc.c
+++ b/drivers/input/touchscreen/imx6ul_tsc.c

@@ -11,15 +11,12 @@
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/gpio.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/of_device.h>
-#include <linux/of_gpio.h>
-#include <linux/of_irq.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>

@@ -85,8 +82,8 @@ struct imx6ul_tsc {
 	void __iomem *adc_regs;
 	struct clk *tsc_clk;
 	struct clk *adc_clk;
+	struct gpio_desc *xnur_gpio;
 
-	int xnur_gpio;
 	int measure_delay_time;
 	int pre_charge_time;
 

@@ -105,6 +102,8 @@ static void imx6ul_adc_init(struct imx6ul_tsc *tsc)
 	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;

@@ -196,17 +195,33 @@ static void imx6ul_tsc_init(struct imx6ul_tsc *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);
+}
+
 static irqreturn_t tsc_irq_fn(int irq, void *dev_id)
 {
 	struct imx6ul_tsc *tsc = (struct imx6ul_tsc *)dev_id;
 	int status;
 	int value;
 	int x, y;
-	int xnur;
 	int debug_mode2;
 	int state_machine;
 	int start;
 	unsigned long timeout;
+	bool touch;
 
 	status = readl(tsc->tsc_regs + REG_TSC_INT_STATUS);
 

@@ -235,8 +250,8 @@ static irqreturn_t tsc_irq_fn(int irq, void *dev_id)
 		timeout = jiffies + HZ/500;
 		do {
 			if (time_after(jiffies, timeout)) {
-				xnur = 0;
-				goto touch_event;
+				touch = true;
+				goto report_touch;
 			}
 			usleep_range(200, 400);
 			debug_mode2 = readl(tsc->tsc_regs + REG_TSC_DEBUG_MODE2);

@@ -244,14 +259,15 @@ static irqreturn_t tsc_irq_fn(int irq, void *dev_id)
 		} while (state_machine != DETECT_MODE);
 		usleep_range(200, 400);
 
-		xnur = gpio_get_value(tsc->xnur_gpio);
-touch_event:
-		if (xnur == 0) {
+		touch = gpiod_get_value_cansleep(tsc->xnur_gpio);
+report_touch:
+		if (touch) {
 			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
+		} else {
 			input_report_key(tsc->input, BTN_TOUCH, 0);
+		}
 
 		input_sync(tsc->input);
 	}

@@ -261,7 +277,7 @@ touch_event:
 
 static irqreturn_t adc_irq_fn(int irq, void *dev_id)
 {
-	struct imx6ul_tsc *tsc = (struct imx6ul_tsc *)dev_id;
+	struct imx6ul_tsc *tsc = dev_id;
 	int coco;
 	int value;
 

@@ -274,70 +290,113 @@ static irqreturn_t adc_irq_fn(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static const struct of_device_id imx6ul_tsc_match[] = {
-	{ .compatible = "fsl,imx6ul-tsc", },
-	{ /* sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
+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;
-	struct input_dev *input_dev;
-	struct device_node *np = pdev->dev.of_node;
 	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;
 
-	tsc->dev = &pdev->dev;
+	input_dev->name = "iMX6UL TouchScreen Controller";
+	input_dev->id.bustype = BUS_HOST;
 
-	tsc->input = input_dev;
-	tsc->input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
-	tsc->input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
-	input_set_abs_params(tsc->input, ABS_X, 0, 0xFFF, 0, 0);
-	input_set_abs_params(tsc->input, ABS_Y, 0, 0xFFF, 0, 0);
+	input_dev->open = imx6ul_tsc_open;
+	input_dev->close = imx6ul_tsc_close;
 
-	tsc->input->name = "iMX6UL TouchScreen Controller";
+	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);
 
-	tsc->xnur_gpio = of_get_named_gpio(np, "xnur-gpio", 0);
-	err = gpio_request_one(tsc->xnur_gpio, GPIOF_IN, "tsc_X-");
-	if (err) {
-		dev_err(&pdev->dev, "failed to request GPIO tsc_X-\n");
+	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-gpio", 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)) {
-		dev_err(&pdev->dev, "failed to remap tsc memory\n");
 		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)) {
-		dev_err(&pdev->dev, "failed to remap adc memory\n");
 		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)) {
-		dev_err(&pdev->dev, "failed getting tsc clock\n");
 		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)) {
-		dev_err(&pdev->dev, "failed getting adc clock\n");
 		err = PTR_ERR(tsc->adc_clk);
+		dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);
 		return err;
 	}
 

@@ -354,111 +413,61 @@ static int imx6ul_tsc_probe(struct platform_device *pdev)
 	}
 
 	err = devm_request_threaded_irq(tsc->dev, tsc_irq,
-					NULL, tsc_irq_fn,
-					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+					NULL, tsc_irq_fn, IRQF_ONESHOT,
 					dev_name(&pdev->dev), tsc);
-	if (err < 0) {
+	if (err) {
 		dev_err(&pdev->dev,
-			"failed requesting tsc irq %d\n",
-					    tsc_irq);
+			"failed requesting tsc irq %di: %d\n",
+			tsc_irq, err);
 		return err;
 	}
 
-	err = devm_request_irq(tsc->dev, adc_irq,
-				adc_irq_fn, 0,
+	err = devm_request_irq(tsc->dev, adc_irq, adc_irq_fn, 0,
 				dev_name(&pdev->dev), tsc);
-	if (err < 0) {
+	if (err) {
 		dev_err(&pdev->dev,
-			"failed requesting adc irq %d\n",
-					    adc_irq);
+			"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);
+				   &tsc->measure_delay_time);
 	if (err)
 		tsc->measure_delay_time = 0xffff;
 
 	err = of_property_read_u32(np, "pre-charge-time",
-				&tsc->pre_charge_time);
+				   &tsc->pre_charge_time);
 	if (err)
 		tsc->pre_charge_time = 0xfff;
 
-	init_completion(&tsc->completion);
-
-	err = clk_prepare_enable(tsc->adc_clk);
+	err = input_register_device(tsc->input);
 	if (err) {
 		dev_err(&pdev->dev,
-			"Could not prepare or enable the adc clock.\n");
+			"failed to register input device: %d\n", err);
 		return err;
 	}
 
-	err = clk_prepare_enable(tsc->tsc_clk);
-	if (err) {
-		dev_err(&pdev->dev,
-			"Could not prepare or enable the tsc clock.\n");
-		goto error_tsc_clk_enable;
-	}
-
-	err = input_register_device(tsc->input);
-	if (err < 0) {
-		dev_err(&pdev->dev, "failed to register input device\n");
-		err = -EIO;
-		goto err_input_register;
-	}
-
-	imx6ul_tsc_init(tsc);
-
 	platform_set_drvdata(pdev, tsc);
 	return 0;
-
-err_input_register:
-	clk_disable_unprepare(tsc->tsc_clk);
-error_tsc_clk_enable:
-	clk_disable_unprepare(tsc->adc_clk);
-
-	return err;
-}
-
-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);
-}
-
-static int imx6ul_tsc_remove(struct platform_device *pdev)
-{
-	struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
-
-	imx6ul_tsc_disable(tsc);
-
-	clk_disable_unprepare(tsc->tsc_clk);
-	clk_disable_unprepare(tsc->adc_clk);
-	input_unregister_device(tsc->input);
-	kfree(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;
 
-	imx6ul_tsc_disable(tsc);
+	mutex_lock(&input_dev->mutex);
 
-	clk_disable_unprepare(tsc->tsc_clk);
-	clk_disable_unprepare(tsc->adc_clk);
+	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;
 }

@@ -467,35 +476,46 @@ 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);
-	int err;
+	struct input_dev *input_dev = tsc->input;
+	int retval = 0;
 
-	err = clk_prepare_enable(tsc->adc_clk);
-	if (err)
-		return err;
+	mutex_lock(&input_dev->mutex);
 
-	err = clk_prepare_enable(tsc->tsc_clk);
-	if (err) {
-		clk_disable_unprepare(tsc->adc_clk);
-		return err;
+	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);
 	}
 
-	imx6ul_tsc_init(tsc);
-	return 0;
+out:
+	mutex_unlock(&input_dev->mutex);
+	return retval;
 }
 
 static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
-			 imx6ul_tsc_suspend,
-			 imx6ul_tsc_resume);
+			 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",
-		.owner	= THIS_MODULE,
 		.of_match_table	= imx6ul_tsc_match,
 		.pm	= &imx6ul_tsc_pm_ops,
 	},
 	.probe		= imx6ul_tsc_probe,
-	.remove		= imx6ul_tsc_remove,
 };
 module_platform_driver(imx6ul_tsc_driver);