1 files changed, 303 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/eeti_ts.c b/drivers/input/touchscreen/eeti_ts.c
new file mode 100644
index 000000000..2e1404cd0
--- /dev/null
+++ b/drivers/input/touchscreen/eeti_ts.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Touch Screen driver for EETI's I2C connected touch screen panels
+ *   Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
+ *
+ * See EETI's software guide for the protocol specification:
+ *   http://home.eeti.com.tw/documentation.html
+ *
+ * Based on migor_ts.c
+ *   Copyright (c) 2008 Magnus Damm
+ *   Copyright (c) 2007 Ujjwal Pande <ujjwal@kenati.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/input.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/timer.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+
+struct eeti_ts {
+	struct i2c_client *client;
+	struct input_dev *input;
+	struct gpio_desc *attn_gpio;
+	struct touchscreen_properties props;
+	struct mutex mutex;
+	bool running;
+};
+
+#define EETI_TS_BITDEPTH	(11)
+#define EETI_MAXVAL		((1 << (EETI_TS_BITDEPTH + 1)) - 1)
+
+#define REPORT_BIT_PRESSED	BIT(0)
+#define REPORT_BIT_AD0		BIT(1)
+#define REPORT_BIT_AD1		BIT(2)
+#define REPORT_BIT_HAS_PRESSURE	BIT(6)
+#define REPORT_RES_BITS(v)	(((v) >> 1) + EETI_TS_BITDEPTH)
+
+static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
+{
+	unsigned int res;
+	u16 x, y;
+
+	res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
+
+	x = get_unaligned_be16(&buf[1]);
+	y = get_unaligned_be16(&buf[3]);
+
+	/* fix the range to 11 bits */
+	x >>= res - EETI_TS_BITDEPTH;
+	y >>= res - EETI_TS_BITDEPTH;
+
+	if (buf[0] & REPORT_BIT_HAS_PRESSURE)
+		input_report_abs(eeti->input, ABS_PRESSURE, buf[5]);
+
+	touchscreen_report_pos(eeti->input, &eeti->props, x, y, false);
+	input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED);
+	input_sync(eeti->input);
+}
+
+static int eeti_ts_read(struct eeti_ts *eeti)
+{
+	int len, error;
+	char buf[6];
+
+	len = i2c_master_recv(eeti->client, buf, sizeof(buf));
+	if (len != sizeof(buf)) {
+		error = len < 0 ? len : -EIO;
+		dev_err(&eeti->client->dev,
+			"failed to read touchscreen data: %d\n",
+			error);
+		return error;
+	}
+
+	/* Motion packet */
+	if (buf[0] & 0x80)
+		eeti_ts_report_event(eeti, buf);
+
+	return 0;
+}
+
+static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
+{
+	struct eeti_ts *eeti = dev_id;
+	int error;
+
+	mutex_lock(&eeti->mutex);
+
+	do {
+		/*
+		 * If we have attention GPIO, trust it. Otherwise we'll read
+		 * once and exit. We assume that in this case we are using
+		 * level triggered interrupt and it will get raised again
+		 * if/when there is more data.
+		 */
+		if (eeti->attn_gpio &&
+		    !gpiod_get_value_cansleep(eeti->attn_gpio)) {
+			break;
+		}
+
+		error = eeti_ts_read(eeti);
+		if (error)
+			break;
+
+	} while (eeti->running && eeti->attn_gpio);
+
+	mutex_unlock(&eeti->mutex);
+	return IRQ_HANDLED;
+}
+
+static void eeti_ts_start(struct eeti_ts *eeti)
+{
+	mutex_lock(&eeti->mutex);
+
+	eeti->running = true;
+	enable_irq(eeti->client->irq);
+
+	/*
+	 * Kick the controller in case we are using edge interrupt and
+	 * we missed our edge while interrupt was disabled. We expect
+	 * the attention GPIO to be wired in this case.
+	 */
+	if (eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio))
+		eeti_ts_read(eeti);
+
+	mutex_unlock(&eeti->mutex);
+}
+
+static void eeti_ts_stop(struct eeti_ts *eeti)
+{
+	/*
+	 * Not locking here, just setting a flag and expect that the
+	 * interrupt thread will notice the flag eventually.
+	 */
+	eeti->running = false;
+	wmb();
+	disable_irq(eeti->client->irq);
+}
+
+static int eeti_ts_open(struct input_dev *dev)
+{
+	struct eeti_ts *eeti = input_get_drvdata(dev);
+
+	eeti_ts_start(eeti);
+
+	return 0;
+}
+
+static void eeti_ts_close(struct input_dev *dev)
+{
+	struct eeti_ts *eeti = input_get_drvdata(dev);
+
+	eeti_ts_stop(eeti);
+}
+
+static int eeti_ts_probe(struct i2c_client *client,
+			 const struct i2c_device_id *idp)
+{
+	struct device *dev = &client->dev;
+	struct eeti_ts *eeti;
+	struct input_dev *input;
+	int error;
+
+	/*
+	 * In contrast to what's described in the datasheet, there seems
+	 * to be no way of probing the presence of that device using I2C
+	 * commands. So we need to blindly believe it is there, and wait
+	 * for interrupts to occur.
+	 */
+
+	eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL);
+	if (!eeti) {
+		dev_err(dev, "failed to allocate driver data\n");
+		return -ENOMEM;
+	}
+
+	mutex_init(&eeti->mutex);
+
+	input = devm_input_allocate_device(dev);
+	if (!input) {
+		dev_err(dev, "Failed to allocate input device.\n");
+		return -ENOMEM;
+	}
+
+	input_set_capability(input, EV_KEY, BTN_TOUCH);
+
+	input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
+	input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
+
+	touchscreen_parse_properties(input, false, &eeti->props);
+
+	input->name = client->name;
+	input->id.bustype = BUS_I2C;
+	input->open = eeti_ts_open;
+	input->close = eeti_ts_close;
+
+	eeti->client = client;
+	eeti->input = input;
+
+	eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN);
+	if (IS_ERR(eeti->attn_gpio))
+		return PTR_ERR(eeti->attn_gpio);
+
+	i2c_set_clientdata(client, eeti);
+	input_set_drvdata(input, eeti);
+
+	error = devm_request_threaded_irq(dev, client->irq,
+					  NULL, eeti_ts_isr,
+					  IRQF_ONESHOT,
+					  client->name, eeti);
+	if (error) {
+		dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
+			error);
+		return error;
+	}
+
+	/*
+	 * Disable the device for now. It will be enabled once the
+	 * input device is opened.
+	 */
+	eeti_ts_stop(eeti);
+
+	error = input_register_device(input);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+static int __maybe_unused eeti_ts_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct eeti_ts *eeti = i2c_get_clientdata(client);
+	struct input_dev *input_dev = eeti->input;
+
+	mutex_lock(&input_dev->mutex);
+
+	if (input_dev->users)
+		eeti_ts_stop(eeti);
+
+	mutex_unlock(&input_dev->mutex);
+
+	if (device_may_wakeup(&client->dev))
+		enable_irq_wake(client->irq);
+
+	return 0;
+}
+
+static int __maybe_unused eeti_ts_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct eeti_ts *eeti = i2c_get_clientdata(client);
+	struct input_dev *input_dev = eeti->input;
+
+	if (device_may_wakeup(&client->dev))
+		disable_irq_wake(client->irq);
+
+	mutex_lock(&input_dev->mutex);
+
+	if (input_dev->users)
+		eeti_ts_start(eeti);
+
+	mutex_unlock(&input_dev->mutex);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
+
+static const struct i2c_device_id eeti_ts_id[] = {
+	{ "eeti_ts", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_eeti_ts_match[] = {
+	{ .compatible = "eeti,exc3000-i2c", },
+	{ }
+};
+#endif
+
+static struct i2c_driver eeti_ts_driver = {
+	.driver = {
+		.name = "eeti_ts",
+		.pm = &eeti_ts_pm,
+		.of_match_table = of_match_ptr(of_eeti_ts_match),
+	},
+	.probe = eeti_ts_probe,
+	.id_table = eeti_ts_id,
+};
+
+module_i2c_driver(eeti_ts_driver);
+
+MODULE_DESCRIPTION("EETI Touchscreen driver");
+MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
+MODULE_LICENSE("GPL");