Input: add support for ChipOne icn8318 based touchscreens

The ChipOne icn8318 is an i2c capacitive touchscreen controller typically
used in cheap android tablets, this commit adds a driver for it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

3 files changed, 330 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index a1cfe16e9a81..547f67d65372 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -140,6 +140,19 @@ config TOUCHSCREEN_BU21013
           To compile this driver as a module, choose M here: the
           module will be called bu21013_ts.
 
+config TOUCHSCREEN_CHIPONE_ICN8318
+        tristate "chipone icn8318 touchscreen controller"
+        depends on GPIOLIB
+        depends on I2C
+        depends on OF
+        help
+          Say Y here if you have a ChipOne icn8318 based I2C touchscreen.
+
+          If unsure, say N.
+
+          To compile this driver as a module, choose M here: the
+          module will be called chipone_icn8318.
+
 config TOUCHSCREEN_CY8CTMG110
         tristate "cy8ctmg110 touchscreen"
         depends on I2C
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 09c33531ab8e..44deea743d02 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_TOUCHSCREEN_AR1021_I2C)	+= ar1021_i2c.o
 obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT)     += atmel_mxt_ts.o
 obj-$(CONFIG_TOUCHSCREEN_AUO_PIXCIR)    += auo-pixcir-ts.o
 obj-$(CONFIG_TOUCHSCREEN_BU21013)       += bu21013_ts.o
+obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8318)       += chipone_icn8318.o
 obj-$(CONFIG_TOUCHSCREEN_CY8CTMG110)    += cy8ctmg110_ts.o
 obj-$(CONFIG_TOUCHSCREEN_CYTTSP_CORE)   += cyttsp_core.o
 obj-$(CONFIG_TOUCHSCREEN_CYTTSP_I2C)    += cyttsp_i2c.o cyttsp_i2c_common.o
diff --git a/drivers/input/touchscreen/chipone_icn8318.c b/drivers/input/touchscreen/chipone_icn8318.c
new file mode 100644
index 000000000000..32e9db0e04bf
--- /dev/null
+++ b/drivers/input/touchscreen/chipone_icn8318.c
@@ -0,0 +1,316 @@
+/*
+ * Driver for ChipOne icn8318 i2c touchscreen controller
+ *
+ * Copyright (c) 2015 Red Hat Inc.
+ *
+ * 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.
+ *
+ * Red Hat authors:
+ * Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#define ICN8318_REG_POWER               4
+#define ICN8318_REG_TOUCHDATA           16
+
+#define ICN8318_POWER_ACTIVE            0
+#define ICN8318_POWER_MONITOR           1
+#define ICN8318_POWER_HIBERNATE         2
+
+#define ICN8318_MAX_TOUCHES             5
+
+struct icn8318_touch {
+        __u8 slot;
+        __be16 x;
+        __be16 y;
+        __u8 pressure;  /* Seems more like finger width then pressure really */
+        __u8 event;
+/* The difference between 2 and 3 is unclear */
+#define ICN8318_EVENT_NO_DATA   1 /* No finger seen yet since wakeup */
+#define ICN8318_EVENT_UPDATE1   2 /* New or updated coordinates */
+#define ICN8318_EVENT_UPDATE2   3 /* New or updated coordinates */
+#define ICN8318_EVENT_END       4 /* Finger lifted */
+} __packed;
+
+struct icn8318_touch_data {
+        __u8 softbutton;
+        __u8 touch_count;
+        struct icn8318_touch touches[ICN8318_MAX_TOUCHES];
+} __packed;
+
+struct icn8318_data {
+        struct i2c_client *client;
+        struct input_dev *input;
+        struct gpio_desc *wake_gpio;
+        u32 max_x;
+        u32 max_y;
+        bool invert_x;
+        bool invert_y;
+        bool swap_x_y;
+};
+
+static int icn8318_read_touch_data(struct i2c_client *client,
+                                   struct icn8318_touch_data *touch_data)
+{
+        u8 reg = ICN8318_REG_TOUCHDATA;
+        struct i2c_msg msg[2] = {
+                {
+                        .addr = client->addr,
+                        .len = 1,
+                        .buf = &reg
+                },
+                {
+                        .addr = client->addr,
+                        .flags = I2C_M_RD,
+                        .len = sizeof(struct icn8318_touch_data),
+                        .buf = (u8 *)touch_data
+                }
+        };
+
+        return i2c_transfer(client->adapter, msg, 2);
+}
+
+static inline bool icn8318_touch_active(u8 event)
+{
+        return (event == ICN8318_EVENT_UPDATE1) ||
+               (event == ICN8318_EVENT_UPDATE2);
+}
+
+static irqreturn_t icn8318_irq(int irq, void *dev_id)
+{
+        struct icn8318_data *data = dev_id;
+        struct device *dev = &data->client->dev;
+        struct icn8318_touch_data touch_data;
+        int i, ret, x, y;
+
+        ret = icn8318_read_touch_data(data->client, &touch_data);
+        if (ret < 0) {
+                dev_err(dev, "Error reading touch data: %d\n", ret);
+                return IRQ_HANDLED;
+        }
+
+        if (touch_data.softbutton) {
+                /*
+                 * Other data is invalid when a softbutton is pressed.
+                 * This needs some extra devicetree bindings to map the icn8318
+                 * softbutton codes to evdev codes. Currently no known devices
+                 * use this.
+                 */
+                return IRQ_HANDLED;
+        }
+
+        if (touch_data.touch_count > ICN8318_MAX_TOUCHES) {
+                dev_warn(dev, "Too much touches %d > %d\n",
+                         touch_data.touch_count, ICN8318_MAX_TOUCHES);
+                touch_data.touch_count = ICN8318_MAX_TOUCHES;
+        }
+
+        for (i = 0; i < touch_data.touch_count; i++) {
+                struct icn8318_touch *touch = &touch_data.touches[i];
+                bool act = icn8318_touch_active(touch->event);
+
+                input_mt_slot(data->input, touch->slot);
+                input_mt_report_slot_state(data->input, MT_TOOL_FINGER, act);
+                if (!act)
+                        continue;
+
+                x = be16_to_cpu(touch->x);
+                y = be16_to_cpu(touch->y);
+
+                if (data->invert_x)
+                        x = data->max_x - x;
+
+                if (data->invert_y)
+                        y = data->max_y - y;
+
+                if (!data->swap_x_y) {
+                        input_event(data->input, EV_ABS, ABS_MT_POSITION_X, x);
+                        input_event(data->input, EV_ABS, ABS_MT_POSITION_Y, y);
+                } else {
+                        input_event(data->input, EV_ABS, ABS_MT_POSITION_X, y);
+                        input_event(data->input, EV_ABS, ABS_MT_POSITION_Y, x);
+                }
+        }
+
+        input_mt_sync_frame(data->input);
+        input_sync(data->input);
+
+        return IRQ_HANDLED;
+}
+
+static int icn8318_start(struct input_dev *dev)
+{
+        struct icn8318_data *data = input_get_drvdata(dev);
+
+        enable_irq(data->client->irq);
+        gpiod_set_value_cansleep(data->wake_gpio, 1);
+
+        return 0;
+}
+
+static void icn8318_stop(struct input_dev *dev)
+{
+        struct icn8318_data *data = input_get_drvdata(dev);
+
+        disable_irq(data->client->irq);
+        i2c_smbus_write_byte_data(data->client, ICN8318_REG_POWER,
+                                  ICN8318_POWER_HIBERNATE);
+        gpiod_set_value_cansleep(data->wake_gpio, 0);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int icn8318_suspend(struct device *dev)
+{
+        struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+        mutex_lock(&data->input->mutex);
+        if (data->input->users)
+                icn8318_stop(data->input);
+        mutex_unlock(&data->input->mutex);
+
+        return 0;
+}
+
+static int icn8318_resume(struct device *dev)
+{
+        struct icn8318_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+        mutex_lock(&data->input->mutex);
+        if (data->input->users)
+                icn8318_start(data->input);
+        mutex_unlock(&data->input->mutex);
+
+        return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(icn8318_pm_ops, icn8318_suspend, icn8318_resume);
+
+static int icn8318_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct device *dev = &client->dev;
+        struct device_node *np = dev->of_node;
+        struct icn8318_data *data;
+        struct input_dev *input;
+        u32 fuzz_x = 0, fuzz_y = 0;
+        int error;
+
+        if (!client->irq) {
+                dev_err(dev, "Error no irq specified\n");
+                return -EINVAL;
+        }
+
+        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        data->wake_gpio = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW);
+        if (IS_ERR(data->wake_gpio)) {
+                error = PTR_ERR(data->wake_gpio);
+                if (error != -EPROBE_DEFER)
+                        dev_err(dev, "Error getting wake gpio: %d\n", error);
+                return error;
+        }
+
+        if (of_property_read_u32(np, "touchscreen-size-x", &data->max_x) ||
+            of_property_read_u32(np, "touchscreen-size-y", &data->max_y)) {
+                dev_err(dev, "Error touchscreen-size-x and/or -y missing\n");
+                return -EINVAL;
+        }
+
+        /* Optional */
+        of_property_read_u32(np, "touchscreen-fuzz-x", &fuzz_x);
+        of_property_read_u32(np, "touchscreen-fuzz-y", &fuzz_y);
+        data->invert_x = of_property_read_bool(np, "touchscreen-inverted-x");
+        data->invert_y = of_property_read_bool(np, "touchscreen-inverted-y");
+        data->swap_x_y = of_property_read_bool(np, "touchscreen-swapped-x-y");
+
+        input = devm_input_allocate_device(dev);
+        if (!input)
+                return -ENOMEM;
+
+        input->name = client->name;
+        input->id.bustype = BUS_I2C;
+        input->open = icn8318_start;
+        input->close = icn8318_stop;
+        input->dev.parent = dev;
+
+        if (!data->swap_x_y) {
+                input_set_abs_params(input, ABS_MT_POSITION_X, 0,
+                                     data->max_x, fuzz_x, 0);
+                input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
+                                     data->max_y, fuzz_y, 0);
+        } else {
+                input_set_abs_params(input, ABS_MT_POSITION_X, 0,
+                                     data->max_y, fuzz_y, 0);
+                input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
+                                     data->max_x, fuzz_x, 0);
+        }
+
+        error = input_mt_init_slots(input, ICN8318_MAX_TOUCHES,
+                                    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+        if (error)
+                return error;
+
+        data->client = client;
+        data->input = input;
+        input_set_drvdata(input, data);
+
+        error = devm_request_threaded_irq(dev, client->irq, NULL, icn8318_irq,
+                                          IRQF_ONESHOT, client->name, data);
+        if (error) {
+                dev_err(dev, "Error requesting irq: %d\n", error);
+                return error;
+        }
+
+        /* Stop device till opened */
+        icn8318_stop(data->input);
+
+        error = input_register_device(input);
+        if (error)
+                return error;
+
+        i2c_set_clientdata(client, data);
+
+        return 0;
+}
+
+static const struct of_device_id icn8318_of_match[] = {
+        { .compatible = "chipone,icn8318" },
+        { }
+};
+MODULE_DEVICE_TABLE(of, icn8318_of_match);
+
+/* This is useless for OF-enabled devices, but it is needed by I2C subsystem */
+static const struct i2c_device_id icn8318_i2c_id[] = {
+        { },
+};
+MODULE_DEVICE_TABLE(i2c, icn8318_i2c_id);
+
+static struct i2c_driver icn8318_driver = {
+        .driver = {
+                .owner  = THIS_MODULE,
+                .name   = "chipone_icn8318",
+                .pm     = &icn8318_pm_ops,
+                .of_match_table = icn8318_of_match,
+        },
+        .probe = icn8318_probe,
+        .id_table = icn8318_i2c_id,
+};
+
+module_i2c_driver(icn8318_driver);
+
+MODULE_DESCRIPTION("ChipOne icn8318 I2C Touchscreen Driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");