[v3,1/2] input: Add new sun4i-ts driver for Allwinner sunxi SoC's rtp controller

diff --git a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
new file mode 100644
index 0000000..e45927e
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
@@ -0,0 +1,15 @@ 
+sun4i resistive touchscreen controller
+--------------------------------------
+
+Required properties:
+ - compatible: "allwinner,sun4i-ts"
+ - reg: mmio address range of the chip
+ - interrupts: interrupt to which the chip is connected
+
+Example:
+
+	rtp: rtp@01c25000 {
+		compatible = "allwinner,sun4i-ts";
+		reg = <0x01c25000 0x100>;
+		interrupts = <29>;
+	};
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 68edc9d..b8366cb 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -897,6 +897,16 @@  config TOUCHSCREEN_STMPE
 	  To compile this driver as a module, choose M here: the
 	  module will be called stmpe-ts.
 
+config TOUCHSCREEN_SUN4I
+	tristate "Allwinner sun4i resistive touchscreen controller support"
+	depends on ARCH_SUNXI
+	help
+	  This selects support for the resistive touchscreen controller
+	  found on Allwinner sunxi SoCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called sun4i-ts.
+
 config TOUCHSCREEN_SUR40
 	tristate "Samsung SUR40 (Surface 2.0/PixelSense) touchscreen"
 	depends on USB
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 4bc954b..71a9755 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -54,6 +54,7 @@  obj-$(CONFIG_TOUCHSCREEN_PIXCIR)	+= pixcir_i2c_ts.o
 obj-$(CONFIG_TOUCHSCREEN_S3C2410)	+= s3c2410_ts.o
 obj-$(CONFIG_TOUCHSCREEN_ST1232)	+= st1232.o
 obj-$(CONFIG_TOUCHSCREEN_STMPE)		+= stmpe-ts.o
+obj-$(CONFIG_TOUCHSCREEN_SUN4I)		+= sun4i-ts.o
 obj-$(CONFIG_TOUCHSCREEN_SUR40)		+= sur40.o
 obj-$(CONFIG_TOUCHSCREEN_TI_AM335X_TSC)	+= ti_am335x_tsc.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)	+= touchit213.o
diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touchscreen/sun4i-ts.c
new file mode 100644
index 0000000..5945219
--- /dev/null
+++ b/drivers/input/touchscreen/sun4i-ts.c
@@ -0,0 +1,262 @@ 
+/*
+ * Allwinner sunxi resistive touchscreen controller driver
+ *
+ * Copyright (C) 2013 - 2014 Hans de Goede <hdegoede@redhat.com>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * The sun4i-ts controller is capable of detecting a second touch, but when a
+ * second touch is present then the accuracy becomes so bad the reported touch
+ * location is not useable.
+ *
+ * The original android driver contains some complicated heuristics using the
+ * aprox. distance between the 2 touches to see if the user is making a pinch
+ * open / close movement, and then reports emulated multi-touch events around
+ * the last touch coordinate (as the dual-touch coordinates are worthless).
+ *
+ * These kinds of heuristics are just asking for trouble (and don't belong
+ * in the kernel). So this driver offers straight forward, reliable single
+ * touch functionality only.
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define TP_CTRL0		0x00
+#define TP_CTRL1		0x04
+#define TP_CTRL2		0x08
+#define TP_CTRL3		0x0c
+#define TP_INT_FIFOC		0x10
+#define TP_INT_FIFOS		0x14
+#define TP_TPR			0x18
+#define TP_CDAT			0x1c
+#define TEMP_DATA		0x20
+#define TP_DATA			0x24
+
+/* TP_CTRL0 bits */
+#define ADC_FIRST_DLY(x)	((x) << 24) /* 8 bits */
+#define ADC_FIRST_DLY_MODE(x)	((x) << 23)
+#define ADC_CLK_SEL(x)		((x) << 22)
+#define ADC_CLK_DIV(x)		((x) << 20) /* 3 bits */
+#define FS_DIV(x)		((x) << 16) /* 4 bits */
+#define T_ACQ(x)		((x) << 0) /* 16 bits */
+
+/* TP_CTRL1 bits */
+#define STYLUS_UP_DEBOUN(x)	((x) << 12) /* 8 bits */
+#define STYLUS_UP_DEBOUN_EN(x)	((x) << 9)
+#define TOUCH_PAN_CALI_EN(x)	((x) << 6)
+#define TP_DUAL_EN(x)		((x) << 5)
+#define TP_MODE_EN(x)		((x) << 4)
+#define TP_ADC_SELECT(x)	((x) << 3)
+#define ADC_CHAN_SELECT(x)	((x) << 0)  /* 3 bits */
+
+/* TP_CTRL2 bits */
+#define TP_SENSITIVE_ADJUST(x)	((x) << 28) /* 4 bits */
+#define TP_MODE_SELECT(x)	((x) << 26) /* 2 bits */
+#define PRE_MEA_EN(x)		((x) << 24)
+#define PRE_MEA_THRE_CNT(x)	((x) << 0) /* 24 bits */
+
+/* TP_CTRL3 bits */
+#define FILTER_EN(x)		((x) << 2)
+#define FILTER_TYPE(x)		((x) << 0)  /* 2 bits */
+
+/* TP_INT_FIFOC irq and fifo mask / control bits */
+#define TEMP_IRQ_EN(x)		((x) << 18)
+#define OVERRUN_IRQ_EN(x)	((x) << 17)
+#define DATA_IRQ_EN(x)		((x) << 16)
+#define TP_DATA_XY_CHANGE(x)	((x) << 13)
+#define FIFO_TRIG(x)		((x) << 8)  /* 5 bits */
+#define DATA_DRQ_EN(x)		((x) << 7)
+#define FIFO_FLUSH(x)		((x) << 4)
+#define TP_UP_IRQ_EN(x)		((x) << 1)
+#define TP_DOWN_IRQ_EN(x)	((x) << 0)
+
+/* TP_INT_FIFOS irq and fifo status bits */
+#define TEMP_DATA_PENDING	BIT(18)
+#define FIFO_OVERRUN_PENDING	BIT(17)
+#define FIFO_DATA_PENDING	BIT(16)
+#define TP_IDLE_FLG		BIT(2)
+#define TP_UP_PENDING		BIT(1)
+#define TP_DOWN_PENDING		BIT(0)
+
+/* TP_TPR bits */
+#define TEMP_ENABLE(x)		((x) << 16)
+#define TEMP_PERIOD(x)		((x) << 0)  /* t = x * 256 * 16 / clkin */
+
+struct sun4i_ts_data {
+	struct device *dev;
+	struct input_dev *input;
+	void __iomem *base;
+	unsigned int irq;
+	bool ignore_fifo_data;
+};
+
+static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
+{
+	struct sun4i_ts_data *ts = dev_id;
+	u32 reg_val, x, y;
+
+	reg_val  = readl(ts->base + TP_INT_FIFOS);
+
+	if (reg_val & FIFO_DATA_PENDING) {
+		x = readl(ts->base + TP_DATA);
+		y = readl(ts->base + TP_DATA);
+		/* The 1st location reported after an up event is unreliable */
+		if (!ts->ignore_fifo_data) {
+			input_report_abs(ts->input, ABS_X, x);
+			input_report_abs(ts->input, ABS_Y, y);
+			/*
+			 * The hardware has a separate down status bit, but
+			 * that gets set before we get the first location,
+			 * resulting in reporting a click on the old location.
+			 */
+			input_report_key(ts->input, BTN_TOUCH, 1);
+			input_sync(ts->input);
+		} else {
+			ts->ignore_fifo_data = false;
+		}
+	}
+
+	if (reg_val & TP_UP_PENDING) {
+		ts->ignore_fifo_data = true;
+		input_report_key(ts->input, BTN_TOUCH, 0);
+		input_sync(ts->input);
+	}
+
+	writel(reg_val, ts->base + TP_INT_FIFOS);
+
+	return IRQ_HANDLED;
+}
+
+static int sun4i_ts_open(struct input_dev *dev)
+{
+	struct sun4i_ts_data *ts = input_get_drvdata(dev);
+
+	/* Flush, set trig level to 1, enable data and up irqs */
+	writel(DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) | TP_UP_IRQ_EN(1),
+	       ts->base + TP_INT_FIFOC);
+
+	return 0;
+}
+
+static void sun4i_ts_close(struct input_dev *dev)
+{
+	struct sun4i_ts_data *ts = input_get_drvdata(dev);
+
+	/* Deactivate all IRQs */
+	writel(0, ts->base + TP_INT_FIFOC);
+}
+
+static int sun4i_ts_probe(struct platform_device *pdev)
+{
+	struct sun4i_ts_data *ts;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->dev = dev;
+	ts->ignore_fifo_data = true;
+
+	ts->input = devm_input_allocate_device(dev);
+	if (!ts->input)
+		return -ENOMEM;
+
+	ts->input->name = pdev->name;
+	ts->input->phys = "sun4i_ts/input0";
+	ts->input->open = sun4i_ts_open;
+	ts->input->close = sun4i_ts_close;
+	ts->input->id.bustype = BUS_HOST;
+	ts->input->id.vendor = 0x0001;
+	ts->input->id.product = 0x0001;
+	ts->input->id.version = 0x0100;
+	ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
+	set_bit(BTN_TOUCH, ts->input->keybit);
+	input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
+	input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
+	input_set_drvdata(ts->input, ts);
+
+	ts->base = devm_ioremap_resource(dev,
+			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
+	if (IS_ERR(ts->base))
+		return PTR_ERR(ts->base);
+
+	ts->irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(dev, ts->irq, sun4i_ts_irq, 0, "sun4i-ts", ts);
+	if (ret)
+		return ret;
+
+	/*
+	 * Select HOSC clk, clkin = clk / 6, adc samplefreq = clkin / 8192,
+	 * t_acq = clkin / (16 * 64)
+	 */
+	writel(ADC_CLK_SEL(0) | ADC_CLK_DIV(2) | FS_DIV(7) | T_ACQ(63),
+	       ts->base + TP_CTRL0);
+
+	/*
+	 * sensitive_adjust = 15 : max, which is not all that sensitive,
+	 * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
+	 */
+	writel(TP_SENSITIVE_ADJUST(15) | TP_MODE_SELECT(0),
+	       ts->base + TP_CTRL2);
+
+	/* Enable median filter, type 1 : 5/3 */
+	writel(FILTER_EN(1) | FILTER_TYPE(1), ts->base + TP_CTRL3);
+
+	/* Enable temperature measurement, period 1953 (2 seconds) */
+	writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);
+
+	/*
+	 * Set stylus up debounce to aprox 10 ms, enable debounce, and
+	 * finally enable tp mode.
+	 */
+	writel(STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1) | TP_MODE_EN(1),
+	       ts->base + TP_CTRL1);
+
+	ret = input_register_device(ts->input);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, ts);
+	return 0;
+}
+
+static const struct of_device_id sun4i_ts_of_match[] = {
+	{ .compatible = "allwinner,sun4i-ts", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
+
+static struct platform_driver sun4i_ts_driver = {
+	.driver = {
+		.owner	= THIS_MODULE,
+		.name	= "sun4i-ts",
+		.of_match_table = of_match_ptr(sun4i_ts_of_match),
+	},
+	.probe	= sun4i_ts_probe,
+};
+
+module_platform_driver(sun4i_ts_driver);
+
+MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");