--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Novatek i2c touchscreen controller as found on
+ * the Acer Iconia One 7 B1-750 tablet. The Touchscreen controller
+ * model-number is unknown. Android calls this a "NVT-ts" touchscreen,
+ * but that may apply to other Novatek controller models too.
+ *
+ * Copyright (c) 2023 Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/module.h>
+
+#include <asm/unaligned.h>
+
+#define NVT_TS_TOUCH_START 0x00
+#define NVT_TS_TOUCH_SIZE 6
+
+#define NVT_TS_PARAMETERS_START 0x78
+/* These are offsets from NVT_TS_PARAMETERS_START */
+#define NVT_TS_PARAMS_WIDTH 0x04
+#define NVT_TS_PARAMS_HEIGHT 0x06
+#define NVT_TS_PARAMS_MAX_TOUCH 0x09
+#define NVT_TS_PARAMS_MAX_BUTTONS 0x0a
+#define NVT_TS_PARAMS_IRQ_TYPE 0x0b
+#define NVT_TS_PARAMS_WAKE_TYPE 0x0c
+#define NVT_TS_PARAMS_CHIP_ID 0x0e
+#define NVT_TS_PARAMS_SIZE 0x0f
+
+#define NVT_TS_SUPPORTED_WAKE_TYPE 0x05
+#define NVT_TS_SUPPORTED_CHIP_ID 0x05
+
+#define NVT_TS_MAX_TOUCHES 10
+#define NVT_TS_MAX_SIZE 4096
+
+#define NVT_TS_TOUCH_INVALID 0xff
+#define NVT_TS_TOUCH_SLOT_SHIFT 3
+#define NVT_TS_TOUCH_TYPE_MASK GENMASK(2, 0)
+#define NVT_TS_TOUCH_NEW 1
+#define NVT_TS_TOUCH_UPDATE 2
+#define NVT_TS_TOUCH_RELEASE 3
+
+static const int nvt_ts_irq_type[4] = {
+ IRQF_TRIGGER_RISING,
+ IRQF_TRIGGER_FALLING,
+ IRQF_TRIGGER_LOW,
+ IRQF_TRIGGER_HIGH
+};
+
+struct nvt_ts_data {
+ struct i2c_client *client;
+ struct input_dev *input;
+ struct gpio_desc *reset_gpio;
+ struct touchscreen_properties prop;
+ int max_touches;
+ u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
+};
+
+static int nvt_ts_read_data(struct i2c_client *client, u8 reg, u8 *data, int count)
+{
+ struct i2c_msg msg[2] = {
+ {
+ .addr = client->addr,
+ .len = 1,
+ .buf = ®,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = count,
+ .buf = data,
+ }
+ };
+ int ret;
+
+ ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+ if (ret != ARRAY_SIZE(msg)) {
+ dev_err(&client->dev, "Error reading from 0x%02x: %d\n", reg, ret);
+ return (ret < 0) ? ret : -EIO;
+ }
+
+ return 0;
+}
+
+static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
+{
+ struct nvt_ts_data *data = dev_id;
+ struct device *dev = &data->client->dev;
+ int i, error, slot, x, y;
+ bool active;
+ u8 *touch;
+
+ error = nvt_ts_read_data(data->client, NVT_TS_TOUCH_START, data->buf,
+ data->max_touches * NVT_TS_TOUCH_SIZE);
+ if (error)
+ return IRQ_HANDLED;
+
+ for (i = 0; i < data->max_touches; i++) {
+ touch = &data->buf[i * NVT_TS_TOUCH_SIZE];
+
+ if (touch[0] == NVT_TS_TOUCH_INVALID)
+ continue;
+
+ slot = touch[0] >> NVT_TS_TOUCH_SLOT_SHIFT;
+ if (slot < 1 || slot > data->max_touches) {
+ dev_warn(dev, "slot %d out of range, ignoring\n", slot);
+ continue;
+ }
+
+ switch (touch[0] & NVT_TS_TOUCH_TYPE_MASK) {
+ case NVT_TS_TOUCH_NEW:
+ case NVT_TS_TOUCH_UPDATE:
+ active = true;
+ break;
+ case NVT_TS_TOUCH_RELEASE:
+ active = false;
+ break;
+ default:
+ dev_warn(dev, "slot %d unknown state %d\n", slot, touch[0] & 7);
+ continue;
+ }
+
+ slot--;
+ x = (touch[1] << 4) | (touch[3] >> 4);
+ y = (touch[2] << 4) | (touch[3] & 0x0f);
+
+ input_mt_slot(data->input, slot);
+ input_mt_report_slot_state(data->input, MT_TOOL_FINGER, active);
+ touchscreen_report_pos(data->input, &data->prop, x, y, true);
+ }
+
+ input_mt_sync_frame(data->input);
+ input_sync(data->input);
+
+ return IRQ_HANDLED;
+}
+
+static int nvt_ts_start(struct input_dev *dev)
+{
+ struct nvt_ts_data *data = input_get_drvdata(dev);
+
+ enable_irq(data->client->irq);
+ gpiod_set_value_cansleep(data->reset_gpio, 0);
+
+ return 0;
+}
+
+static void nvt_ts_stop(struct input_dev *dev)
+{
+ struct nvt_ts_data *data = input_get_drvdata(dev);
+
+ disable_irq(data->client->irq);
+ gpiod_set_value_cansleep(data->reset_gpio, 1);
+}
+
+static int nvt_ts_suspend(struct device *dev)
+{
+ struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+ mutex_lock(&data->input->mutex);
+ if (input_device_enabled(data->input))
+ nvt_ts_stop(data->input);
+ mutex_unlock(&data->input->mutex);
+
+ return 0;
+}
+
+static int nvt_ts_resume(struct device *dev)
+{
+ struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+ mutex_lock(&data->input->mutex);
+ if (input_device_enabled(data->input))
+ nvt_ts_start(data->input);
+ mutex_unlock(&data->input->mutex);
+
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(nvt_ts_pm_ops, nvt_ts_suspend, nvt_ts_resume);
+
+static int nvt_ts_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ int error, width, height, irq_type;
+ struct nvt_ts_data *data;
+ struct input_dev *input;
+
+ 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->client = client;
+ i2c_set_clientdata(client, data);
+
+ data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+ error = PTR_ERR_OR_ZERO(data->reset_gpio);
+ if (error) {
+ dev_err(dev, "failed to request reset GPIO: %d\n", error);
+ return error;
+ }
+
+ /* Wait for controller to come out of reset before params read */
+ msleep(100);
+ error = nvt_ts_read_data(data->client, NVT_TS_PARAMETERS_START,
+ data->buf, NVT_TS_PARAMS_SIZE);
+ gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
+ if (error)
+ return error;
+
+ width = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
+ height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
+ data->max_touches = data->buf[NVT_TS_PARAMS_MAX_TOUCH];
+ irq_type = data->buf[NVT_TS_PARAMS_IRQ_TYPE];
+
+ if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
+ data->max_touches > NVT_TS_MAX_TOUCHES ||
+ irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
+ data->buf[NVT_TS_PARAMS_WAKE_TYPE] != NVT_TS_SUPPORTED_WAKE_TYPE ||
+ data->buf[NVT_TS_PARAMS_CHIP_ID] != NVT_TS_SUPPORTED_CHIP_ID) {
+ dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
+ NVT_TS_PARAMS_SIZE, data->buf);
+ return -EIO;
+ }
+
+ dev_dbg(dev, "Detected %dx%d touchscreen with %d max touches\n",
+ width, height, data->max_touches);
+
+ if (data->buf[NVT_TS_PARAMS_MAX_BUTTONS])
+ dev_warn(dev, "Touchscreen buttons are not supported\n");
+
+ input = devm_input_allocate_device(dev);
+ if (!input)
+ return -ENOMEM;
+
+ input->name = client->name;
+ input->id.bustype = BUS_I2C;
+ input->open = nvt_ts_start;
+ input->close = nvt_ts_stop;
+
+ input_set_abs_params(input, ABS_MT_POSITION_X, 0, width - 1, 0, 0);
+ input_set_abs_params(input, ABS_MT_POSITION_Y, 0, height - 1, 0, 0);
+ touchscreen_parse_properties(input, true, &data->prop);
+
+ error = input_mt_init_slots(input, data->max_touches,
+ INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+ if (error)
+ return error;
+
+ data->input = input;
+ input_set_drvdata(input, data);
+
+ error = devm_request_threaded_irq(dev, client->irq, NULL, nvt_ts_irq,
+ IRQF_ONESHOT | IRQF_NO_AUTOEN |
+ nvt_ts_irq_type[irq_type],
+ client->name, data);
+ if (error) {
+ dev_err(dev, "failed to request irq: %d\n", error);
+ return error;
+ }
+
+ error = input_register_device(input);
+ if (error) {
+ dev_err(dev, "failed to request irq: %d\n", error);
+ return error;
+ }
+
+ return 0;
+}
+
+static const struct i2c_device_id nvt_ts_i2c_id[] = {
+ { "NVT-ts" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
+
+static struct i2c_driver nvt_ts_driver = {
+ .driver = {
+ .name = "novatek-nvt-ts",
+ .pm = pm_sleep_ptr(&nvt_ts_pm_ops),
+ },
+ .probe_new = nvt_ts_probe,
+ .id_table = nvt_ts_i2c_id,
+};
+
+module_i2c_driver(nvt_ts_driver);
+
+MODULE_DESCRIPTION("Novatek NVT-ts touchscreen driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-starfive.git / commitdiff