Input: add Broadcom iProc touchscreen driver

Add initial version of the Broadcom touchscreen driver.

Reviewed-by: Ray Jui <[e-mail]>
Reviewed-by: Scott Branden <[e-mail]>
Tested-by: Scott Branden <[e-mail]>
Signed-off-by: Jonathan Richardson <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt

···
+* Broadcom's IPROC Touchscreen Controller
+
+Required properties:
+- compatible: must be "brcm,iproc-touchscreen"
+- reg: physical base address of the controller and length of memory mapped
+  region.
+- clocks:  The clock provided by the SOC to driver the tsc
+- clock-name:  name for the clock
+- interrupts: The touchscreen controller's interrupt
+
+Optional properties:
+- scanning_period: Time between scans. Each step is 1024 us.  Valid 1-256.
+- debounce_timeout: Each step is 512 us.  Valid 0-255
+- settling_timeout: The settling duration (in ms) is the amount of time
+                    the tsc waits to allow the voltage to settle after
+                    turning on the drivers in detection mode.
+                    Valid values: 0-11
+                    0 =  0.008 ms
+                    1 =  0.01 ms
+                    2 =  0.02 ms
+                    3 =  0.04 ms
+                    4 =  0.08 ms
+                    5 =  0.16 ms
+                    6 =  0.32 ms
+                    7 =  0.64 ms
+                    8 =  1.28 ms
+                    9 =  2.56 ms
+                   10 =  5.12 ms
+                   11 = 10.24 ms
+- touch_timeout: The continuous number of scan periods in which touch is
+                not detected before the controller returns to idle state.
+                Valid values 0-255.
+- average_data: Number of data samples which are averaged before a final
+                data point is placed into the FIFO
+                Valid values 0-7
+                0 =   1 sample
+                1 =   2 samples
+                2 =   4 samples
+                3 =   8 samples
+                4 =  16 samples
+                5 =  32 samples
+                6 =  64 samples
+                7 = 128 samples
+- fifo_threshold: Interrupt is generated whenever the number of fifo
+                entries exceeds this value
+                Valid values 0-31
+- touchscreen-size-x: horizontal resolution of touchscreen (in pixels)
+- touchscreen-size-y: vertical resolution of touchscreen (in pixels)
+- touchscreen-fuzz-x: horizontal noise value of the absolute input
+                      device (in pixels)
+- touchscreen-fuzz-y: vertical noise value of the absolute input
+                      device (in pixels)
+- touchscreen-inverted-x: X axis is inverted (boolean)
+- touchscreen-inverted-y: Y axis is inverted (boolean)
+
+Example:
+
+	touchscreen: tsc@0x180A6000 {
+		compatible = "brcm,iproc-touchscreen";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		reg = <0x180A6000 0x40>;
+		clocks = <&adc_clk>;
+		clock-names = "tsc_clk";
+		interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;
+
+		scanning_period = <5>;
+		debounce_timeout = <40>;
+		settling_timeout = <7>;
+		touch_timeout = <10>;
+		average_data = <5>;
+		fifo_threshold = <1>;
+		/* Touchscreen is rotated 180 degrees. */
+		touchscreen-inverted-x;
+		touchscreen-inverted-y;
+	};

drivers/input/touchscreen/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called ili210x.
 
+config TOUCHSCREEN_IPROC
+	tristate "IPROC touch panel driver support"
+	depends on ARCH_BCM_IPROC || COMPILE_TEST
+	help
+	  Say Y here if you want to add support for the IPROC touch
+	  controller to your system.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called bcm_iproc_tsc.
+
 config TOUCHSCREEN_S3C2410
 	tristate "Samsung S3C2410/generic touchscreen input driver"
 	depends on ARCH_S3C24XX || SAMSUNG_DEV_TS

drivers/input/touchscreen/Makefile

···
 obj-$(CONFIG_TOUCHSCREEN_ILI210X)	+= ili210x.o
 obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
 obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o
+obj-$(CONFIG_TOUCHSCREEN_IPROC)		+= bcm_iproc_tsc.o
 obj-$(CONFIG_TOUCHSCREEN_LPC32XX)	+= lpc32xx_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MAX11801)	+= max11801_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MC13783)	+= mc13783_ts.o

drivers/input/touchscreen/bcm_iproc_tsc.c

···
+/*
+* Copyright (C) 2015 Broadcom Corporation
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License as
+* published by the Free Software Foundation version 2.
+*
+* This program is distributed "as is" WITHOUT ANY WARRANTY of any
+* kind, whether express or implied; without even the implied warranty
+* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU General Public License for more details.
+*/
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/keyboard.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <asm/irq.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/serio.h>
+
+#define IPROC_TS_NAME "iproc-ts"
+
+#define PEN_DOWN_STATUS     1
+#define PEN_UP_STATUS       0
+
+#define X_MIN               0
+#define Y_MIN               0
+#define X_MAX               0xFFF
+#define Y_MAX               0xFFF
+
+/* Value given by controller for invalid coordinate. */
+#define INVALID_COORD       0xFFFFFFFF
+
+/* Register offsets */
+#define REGCTL1             0x00
+#define REGCTL2             0x04
+#define INTERRUPT_THRES     0x08
+#define INTERRUPT_MASK      0x0c
+
+#define INTERRUPT_STATUS    0x10
+#define CONTROLLER_STATUS   0x14
+#define FIFO_DATA           0x18
+#define FIFO_DATA_X_Y_MASK  0xFFFF
+#define ANALOG_CONTROL      0x1c
+
+#define AUX_DATA            0x20
+#define DEBOUNCE_CNTR_STAT  0x24
+#define SCAN_CNTR_STAT      0x28
+#define REM_CNTR_STAT       0x2c
+
+#define SETTLING_TIMER_STAT 0x30
+#define SPARE_REG           0x34
+#define SOFT_BYPASS_CONTROL 0x38
+#define SOFT_BYPASS_DATA    0x3c
+
+
+/* Bit values for INTERRUPT_MASK and INTERRUPT_STATUS regs */
+#define TS_PEN_INTR_MASK        BIT(0)
+#define TS_FIFO_INTR_MASK       BIT(2)
+
+/* Bit values for CONTROLLER_STATUS reg1 */
+#define TS_PEN_DOWN             BIT(0)
+
+/* Shift values for control reg1 */
+#define SCANNING_PERIOD_SHIFT   24
+#define DEBOUNCE_TIMEOUT_SHIFT  16
+#define SETTLING_TIMEOUT_SHIFT  8
+#define TOUCH_TIMEOUT_SHIFT     0
+
+/* Shift values for coordinates from fifo */
+#define X_COORD_SHIFT  0
+#define Y_COORD_SHIFT  16
+
+/* Bit values for REGCTL2 */
+#define TS_CONTROLLER_EN_BIT    BIT(16)
+#define TS_CONTROLLER_AVGDATA_SHIFT 8
+#define TS_CONTROLLER_AVGDATA_MASK (0x7 << TS_CONTROLLER_AVGDATA_SHIFT)
+#define TS_CONTROLLER_PWR_LDO   BIT(5)
+#define TS_CONTROLLER_PWR_ADC   BIT(4)
+#define TS_CONTROLLER_PWR_BGP   BIT(3)
+#define TS_CONTROLLER_PWR_TS    BIT(2)
+#define TS_WIRE_MODE_BIT        BIT(1)
+
+#define dbg_reg(dev, priv, reg) \
+	dev_dbg(dev, "%20s= 0x%08x\n", #reg, readl((priv)->regs + reg))
+
+struct tsc_param {
+	/* Each step is 1024 us.  Valid 1-256 */
+	u32 scanning_period;
+
+	/*  Each step is 512 us.  Valid 0-255 */
+	u32 debounce_timeout;
+
+	/*
+	 * The settling duration (in ms) is the amount of time the tsc
+	 * waits to allow the voltage to settle after turning on the
+	 * drivers in detection mode. Valid values: 0-11
+	 *   0 =  0.008 ms
+	 *   1 =  0.01 ms
+	 *   2 =  0.02 ms
+	 *   3 =  0.04 ms
+	 *   4 =  0.08 ms
+	 *   5 =  0.16 ms
+	 *   6 =  0.32 ms
+	 *   7 =  0.64 ms
+	 *   8 =  1.28 ms
+	 *   9 =  2.56 ms
+	 *   10 = 5.12 ms
+	 *   11 = 10.24 ms
+	 */
+	u32 settling_timeout;
+
+	/* touch timeout in sample counts */
+	u32 touch_timeout;
+
+	/*
+	 * Number of data samples which are averaged before a final data point
+	 * is placed into the FIFO
+	 */
+	u32 average_data;
+
+	/* FIFO threshold */
+	u32 fifo_threshold;
+
+	/* Optional standard touchscreen properties. */
+	u32 max_x;
+	u32 max_y;
+	u32 fuzz_x;
+	u32 fuzz_y;
+	bool invert_x;
+	bool invert_y;
+};
+
+struct iproc_ts_priv {
+	struct platform_device *pdev;
+	struct input_dev *idev;
+
+	void __iomem *regs;
+	struct clk *tsc_clk;
+
+	int  pen_status;
+	struct tsc_param cfg_params;
+};
+
+/*
+ * Set default values the same as hardware reset values
+ * except for fifo_threshold with is set to 1.
+ */
+static const struct tsc_param iproc_default_config = {
+	.scanning_period  = 0x5,  /* 1 to 256 */
+	.debounce_timeout = 0x28, /* 0 to 255 */
+	.settling_timeout = 0x7,  /* 0 to 11 */
+	.touch_timeout    = 0xa,  /* 0 to 255 */
+	.average_data     = 5,    /* entry 5 = 32 pts */
+	.fifo_threshold   = 1,    /* 0 to 31 */
+	.max_x            = X_MAX,
+	.max_y            = Y_MAX,
+};
+
+static void ts_reg_dump(struct iproc_ts_priv *priv)
+{
+	struct device *dev = &priv->pdev->dev;
+
+	dbg_reg(dev, priv, REGCTL1);
+	dbg_reg(dev, priv, REGCTL2);
+	dbg_reg(dev, priv, INTERRUPT_THRES);
+	dbg_reg(dev, priv, INTERRUPT_MASK);
+	dbg_reg(dev, priv, INTERRUPT_STATUS);
+	dbg_reg(dev, priv, CONTROLLER_STATUS);
+	dbg_reg(dev, priv, FIFO_DATA);
+	dbg_reg(dev, priv, ANALOG_CONTROL);
+	dbg_reg(dev, priv, AUX_DATA);
+	dbg_reg(dev, priv, DEBOUNCE_CNTR_STAT);
+	dbg_reg(dev, priv, SCAN_CNTR_STAT);
+	dbg_reg(dev, priv, REM_CNTR_STAT);
+	dbg_reg(dev, priv, SETTLING_TIMER_STAT);
+	dbg_reg(dev, priv, SPARE_REG);
+	dbg_reg(dev, priv, SOFT_BYPASS_CONTROL);
+	dbg_reg(dev, priv, SOFT_BYPASS_DATA);
+}
+
+static irqreturn_t iproc_touchscreen_interrupt(int irq, void *data)
+{
+	struct platform_device *pdev = data;
+	struct iproc_ts_priv *priv = platform_get_drvdata(pdev);
+	u32 intr_status;
+	u32 raw_coordinate;
+	u16 x;
+	u16 y;
+	int i;
+	bool needs_sync = false;
+
+	intr_status = readl(priv->regs + INTERRUPT_STATUS);
+	intr_status &= TS_PEN_INTR_MASK | TS_FIFO_INTR_MASK;
+	if (intr_status == 0)
+		return IRQ_NONE;
+
+	/* Clear all interrupt status bits, write-1-clear */
+	writel(intr_status, priv->regs + INTERRUPT_STATUS);
+
+	/* Pen up/down */
+	if (intr_status & TS_PEN_INTR_MASK) {
+		if (readl(priv->regs + CONTROLLER_STATUS) & TS_PEN_DOWN)
+			priv->pen_status = PEN_DOWN_STATUS;
+		else
+			priv->pen_status = PEN_UP_STATUS;
+
+		input_report_key(priv->idev, BTN_TOUCH, priv->pen_status);
+		needs_sync = true;
+
+		dev_dbg(&priv->pdev->dev,
+			"pen up-down (%d)\n", priv->pen_status);
+	}
+
+	/* coordinates in FIFO exceed the theshold */
+	if (intr_status & TS_FIFO_INTR_MASK) {
+		for (i = 0; i < priv->cfg_params.fifo_threshold; i++) {
+			raw_coordinate = readl(priv->regs + FIFO_DATA);
+			if (raw_coordinate == INVALID_COORD)
+				continue;
+
+			/*
+			 * The x and y coordinate are 16 bits each
+			 * with the x in the lower 16 bits and y in the
+			 * upper 16 bits.
+			 */
+			x = (raw_coordinate >> X_COORD_SHIFT) &
+				FIFO_DATA_X_Y_MASK;
+			y = (raw_coordinate >> Y_COORD_SHIFT) &
+				FIFO_DATA_X_Y_MASK;
+
+			/* We only want to retain the 12 msb of the 16 */
+			x = (x >> 4) & 0x0FFF;
+			y = (y >> 4) & 0x0FFF;
+
+			/* adjust x y according to lcd tsc mount angle */
+			if (priv->cfg_params.invert_x)
+				x = priv->cfg_params.max_x - x;
+
+			if (priv->cfg_params.invert_y)
+				y = priv->cfg_params.max_y - y;
+
+			input_report_abs(priv->idev, ABS_X, x);
+			input_report_abs(priv->idev, ABS_Y, y);
+			needs_sync = true;
+
+			dev_dbg(&priv->pdev->dev, "xy (0x%x 0x%x)\n", x, y);
+		}
+	}
+
+	if (needs_sync)
+		input_sync(priv->idev);
+
+	return IRQ_HANDLED;
+}
+
+static int iproc_ts_start(struct input_dev *idev)
+{
+	struct iproc_ts_priv *priv = input_get_drvdata(idev);
+	u32 val;
+	int error;
+
+	/* Enable clock */
+	error = clk_prepare_enable(priv->tsc_clk);
+	if (error) {
+		dev_err(&priv->pdev->dev, "%s clk_prepare_enable failed %d\n",
+			__func__, error);
+		return error;
+	}
+
+	/*
+	 * Interrupt is generated when:
+	 *  FIFO reaches the int_th value, and pen event(up/down)
+	 */
+	val = TS_PEN_INTR_MASK | TS_FIFO_INTR_MASK;
+	writel(val, priv->regs + INTERRUPT_MASK);
+
+	writel(priv->cfg_params.fifo_threshold, priv->regs + INTERRUPT_THRES);
+
+	/* Initialize control reg1 */
+	val = 0;
+	val |= priv->cfg_params.scanning_period << SCANNING_PERIOD_SHIFT;
+	val |= priv->cfg_params.debounce_timeout << DEBOUNCE_TIMEOUT_SHIFT;
+	val |= priv->cfg_params.settling_timeout << SETTLING_TIMEOUT_SHIFT;
+	val |= priv->cfg_params.touch_timeout << TOUCH_TIMEOUT_SHIFT;
+	writel(val, priv->regs + REGCTL1);
+
+	/* Try to clear all interrupt status */
+	val = readl(priv->regs + INTERRUPT_STATUS);
+	val |= TS_FIFO_INTR_MASK | TS_PEN_INTR_MASK;
+	writel(val, priv->regs + INTERRUPT_STATUS);
+
+	/* Initialize control reg2 */
+	val = readl(priv->regs + REGCTL2);
+	val |= TS_CONTROLLER_EN_BIT | TS_WIRE_MODE_BIT;
+
+	val &= ~TS_CONTROLLER_AVGDATA_MASK;
+	val |= priv->cfg_params.average_data << TS_CONTROLLER_AVGDATA_SHIFT;
+
+	val &= ~(TS_CONTROLLER_PWR_LDO |	/* PWR up LDO */
+		   TS_CONTROLLER_PWR_ADC |	/* PWR up ADC */
+		   TS_CONTROLLER_PWR_BGP |	/* PWR up BGP */
+		   TS_CONTROLLER_PWR_TS);	/* PWR up TS */
+
+	writel(val, priv->regs + REGCTL2);
+
+	ts_reg_dump(priv);
+
+	return 0;
+}
+
+static void iproc_ts_stop(struct input_dev *dev)
+{
+	u32 val;
+	struct iproc_ts_priv *priv = input_get_drvdata(dev);
+
+	writel(0, priv->regs + INTERRUPT_MASK); /* Disable all interrupts */
+
+	/* Only power down touch screen controller */
+	val = readl(priv->regs + REGCTL2);
+	val |= TS_CONTROLLER_PWR_TS;
+	writel(val, priv->regs + REGCTL2);
+
+	clk_disable(priv->tsc_clk);
+}
+
+static int iproc_get_tsc_config(struct device *dev, struct iproc_ts_priv *priv)
+{
+	struct device_node *np = dev->of_node;
+	u32 val;
+
+	priv->cfg_params = iproc_default_config;
+
+	if (!np)
+		return 0;
+
+	if (of_property_read_u32(np, "scanning_period", &val) >= 0) {
+		if (val < 1 || val > 256) {
+			dev_err(dev, "scanning_period (%u) must be [1-256]\n",
+				val);
+			return -EINVAL;
+		}
+		priv->cfg_params.scanning_period = val;
+	}
+
+	if (of_property_read_u32(np, "debounce_timeout", &val) >= 0) {
+		if (val > 255) {
+			dev_err(dev, "debounce_timeout (%u) must be [0-255]\n",
+				val);
+			return -EINVAL;
+		}
+		priv->cfg_params.debounce_timeout = val;
+	}
+
+	if (of_property_read_u32(np, "settling_timeout", &val) >= 0) {
+		if (val > 11) {
+			dev_err(dev, "settling_timeout (%u) must be [0-11]\n",
+				val);
+			return -EINVAL;
+		}
+		priv->cfg_params.settling_timeout = val;
+	}
+
+	if (of_property_read_u32(np, "touch_timeout", &val) >= 0) {
+		if (val > 255) {
+			dev_err(dev, "touch_timeout (%u) must be [0-255]\n",
+				val);
+			return -EINVAL;
+		}
+		priv->cfg_params.touch_timeout = val;
+	}
+
+	if (of_property_read_u32(np, "average_data", &val) >= 0) {
+		if (val > 8) {
+			dev_err(dev, "average_data (%u) must be [0-8]\n", val);
+			return -EINVAL;
+		}
+		priv->cfg_params.average_data = val;
+	}
+
+	if (of_property_read_u32(np, "fifo_threshold", &val) >= 0) {
+		if (val > 31) {
+			dev_err(dev, "fifo_threshold (%u)) must be [0-31]\n",
+				val);
+			return -EINVAL;
+		}
+		priv->cfg_params.fifo_threshold = val;
+	}
+
+	/* Parse optional properties. */
+	of_property_read_u32(np, "touchscreen-size-x", &priv->cfg_params.max_x);
+	of_property_read_u32(np, "touchscreen-size-y", &priv->cfg_params.max_y);
+
+	of_property_read_u32(np, "touchscreen-fuzz-x",
+			     &priv->cfg_params.fuzz_x);
+	of_property_read_u32(np, "touchscreen-fuzz-y",
+			     &priv->cfg_params.fuzz_y);
+
+	priv->cfg_params.invert_x =
+		of_property_read_bool(np, "touchscreen-inverted-x");
+	priv->cfg_params.invert_y =
+		of_property_read_bool(np, "touchscreen-inverted-y");
+
+	return 0;
+}
+
+static int iproc_ts_probe(struct platform_device *pdev)
+{
+	struct iproc_ts_priv *priv;
+	struct input_dev *idev;
+	struct resource *res;
+	int irq;
+	int error;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/* touchscreen controller memory mapped regs */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->regs)) {
+		error = PTR_ERR(priv->regs);
+		dev_err(&pdev->dev, "unable to map I/O memory: %d\n", error);
+		return error;
+	}
+
+	priv->tsc_clk = devm_clk_get(&pdev->dev, "tsc_clk");
+	if (IS_ERR(priv->tsc_clk)) {
+		error = PTR_ERR(priv->tsc_clk);
+		dev_err(&pdev->dev,
+			"failed getting clock tsc_clk: %d\n", error);
+		return error;
+	}
+
+	priv->pdev = pdev;
+	error = iproc_get_tsc_config(&pdev->dev, priv);
+	if (error) {
+		dev_err(&pdev->dev, "get_tsc_config failed: %d\n", error);
+		return error;
+	}
+
+	idev = devm_input_allocate_device(&pdev->dev);
+	if (!idev) {
+		dev_err(&pdev->dev, "failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	priv->idev = idev;
+	priv->pen_status = PEN_UP_STATUS;
+
+	/* Set input device info  */
+	idev->name = IPROC_TS_NAME;
+	idev->dev.parent = &pdev->dev;
+
+	idev->id.bustype = BUS_HOST;
+	idev->id.vendor = SERIO_UNKNOWN;
+	idev->id.product = 0;
+	idev->id.version = 0;
+
+	idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	__set_bit(BTN_TOUCH, idev->keybit);
+
+	input_set_abs_params(idev, ABS_X, X_MIN, priv->cfg_params.max_x,
+			     priv->cfg_params.fuzz_x, 0);
+	input_set_abs_params(idev, ABS_Y, Y_MIN, priv->cfg_params.max_y,
+			     priv->cfg_params.fuzz_y, 0);
+
+	idev->open = iproc_ts_start;
+	idev->close = iproc_ts_stop;
+
+	input_set_drvdata(idev, priv);
+	platform_set_drvdata(pdev, priv);
+
+	/* get interrupt */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "platform_get_irq failed: %d\n", irq);
+		return irq;
+	}
+
+	error = devm_request_irq(&pdev->dev, irq,
+				 iproc_touchscreen_interrupt,
+				 IRQF_SHARED, IPROC_TS_NAME, pdev);
+	if (error)
+		return error;
+
+	error = input_register_device(priv->idev);
+	if (error) {
+		dev_err(&pdev->dev,
+			"failed to register input device: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id iproc_ts_of_match[] = {
+	{.compatible = "brcm,iproc-touchscreen", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, iproc_ts_of_match);
+
+static struct platform_driver iproc_ts_driver = {
+	.probe = iproc_ts_probe,
+	.driver = {
+		.name	= IPROC_TS_NAME,
+		.of_match_table = of_match_ptr(iproc_ts_of_match),
+	},
+};
+
+module_platform_driver(iproc_ts_driver);
+
+MODULE_DESCRIPTION("IPROC Touchscreen driver");
+MODULE_AUTHOR("Broadcom");
+MODULE_LICENSE("GPL v2");