Input: touchscreen - add imx6ul_tsc driver support

Freescale i.MX6UL contains a internal touchscreen controller,
this patch add a driver to support this controller.
Signed-off-by: Haibo Chen <haibo.chen@freescale.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt

+* 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";
+	};

drivers/input/touchscreen/Kconfig

@@ -479,6 +479,18 @@ config TOUCHSCREEN_MTOUCH
 	  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

drivers/input/touchscreen/Makefile

@@ -38,6 +38,7 @@ obj-$(CONFIG_TOUCHSCREEN_EGALAX)	+= egalax_ts.o
 obj-$(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

drivers/input/touchscreen/imx6ul_tsc.c

+/*
+ * 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");