// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Driver for Ntrig/Microsoft Touchscreens over SPI
 *
 *  Copyright (c) 2016 Red Hat Inc.
 */


#include <linux/kernel.h>

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/acpi.h>

#include <linux/unaligned.h>

#define SURFACE3_PACKET_SIZE    264

#define SURFACE3_REPORT_TOUCH   0xd2
#define SURFACE3_REPORT_PEN     0x16

struct surface3_ts_data {
        struct spi_device *spi;
        struct gpio_desc *gpiod_rst[2];
        struct input_dev *input_dev;
        struct input_dev *pen_input_dev;
        int pen_tool;

        u8 rd_buf[SURFACE3_PACKET_SIZE]         ____cacheline_aligned;
};

struct surface3_ts_data_finger {
        u8 status;
        __le16 tracking_id;
        __le16 x;
        __le16 cx;
        __le16 y;
        __le16 cy;
        __le16 width;
        __le16 height;
        u32 padding;
} __packed;

struct surface3_ts_data_pen {
        u8 status;
        __le16 x;
        __le16 y;
        __le16 pressure;
        u8 padding;
} __packed;

static int surface3_spi_read(struct surface3_ts_data *ts_data)
{
        struct spi_device *spi = ts_data->spi;

        memset(ts_data->rd_buf, 0, sizeof(ts_data->rd_buf));
        return spi_read(spi, ts_data->rd_buf, sizeof(ts_data->rd_buf));
}

static void surface3_spi_report_touch(struct surface3_ts_data *ts_data,
                                   struct surface3_ts_data_finger *finger)
{
        int st = finger->status & 0x01;
        int slot;

        slot = input_mt_get_slot_by_key(ts_data->input_dev,
                                get_unaligned_le16(&finger->tracking_id));
        if (slot < 0)
                return;

        input_mt_slot(ts_data->input_dev, slot);
        input_mt_report_slot_state(ts_data->input_dev, MT_TOOL_FINGER, st);
        if (st) {
                input_report_abs(ts_data->input_dev,
                                 ABS_MT_POSITION_X,
                                 get_unaligned_le16(&finger->x));
                input_report_abs(ts_data->input_dev,
                                 ABS_MT_POSITION_Y,
                                 get_unaligned_le16(&finger->y));
                input_report_abs(ts_data->input_dev,
                                 ABS_MT_WIDTH_MAJOR,
                                 get_unaligned_le16(&finger->width));
                input_report_abs(ts_data->input_dev,
                                 ABS_MT_WIDTH_MINOR,
                                 get_unaligned_le16(&finger->height));
        }
}

static void surface3_spi_process_touch(struct surface3_ts_data *ts_data, u8 *data)
{
        unsigned int i;

        for (i = 0; i < 13; i++) {
                struct surface3_ts_data_finger *finger;

                finger = (struct surface3_ts_data_finger *)&data[17 +
                                i * sizeof(struct surface3_ts_data_finger)];

                /*
                 * When bit 5 of status is 1, it marks the end of the report:
                 * - touch present: 0xe7
                 * - touch released: 0xe4
                 * - nothing valuable: 0xff
                 */
                if (finger->status & 0x10)
                        break;

                surface3_spi_report_touch(ts_data, finger);
        }

        input_mt_sync_frame(ts_data->input_dev);
        input_sync(ts_data->input_dev);
}

static void surface3_spi_report_pen(struct surface3_ts_data *ts_data,
                                    struct surface3_ts_data_pen *pen)
{
        struct input_dev *dev = ts_data->pen_input_dev;
        int st = pen->status;
        int prox = st & 0x01;
        int rubber = st & 0x18;
        int tool = (prox && rubber) ? BTN_TOOL_RUBBER : BTN_TOOL_PEN;

        /* fake proximity out to switch tools */
        if (ts_data->pen_tool != tool) {
                input_report_key(dev, ts_data->pen_tool, 0);
                input_sync(dev);
                ts_data->pen_tool = tool;
        }

        input_report_key(dev, BTN_TOUCH, st & 0x12);

        input_report_key(dev, ts_data->pen_tool, prox);

        if (st) {
                input_report_key(dev,
                                 BTN_STYLUS,
                                 st & 0x04);

                input_report_abs(dev,
                                 ABS_X,
                                 get_unaligned_le16(&pen->x));
                input_report_abs(dev,
                                 ABS_Y,
                                 get_unaligned_le16(&pen->y));
                input_report_abs(dev,
                                 ABS_PRESSURE,
                                 get_unaligned_le16(&pen->pressure));
        }
}

static void surface3_spi_process_pen(struct surface3_ts_data *ts_data, u8 *data)
{
        struct surface3_ts_data_pen *pen;

        pen = (struct surface3_ts_data_pen *)&data[15];

        surface3_spi_report_pen(ts_data, pen);
        input_sync(ts_data->pen_input_dev);
}

static void surface3_spi_process(struct surface3_ts_data *ts_data)
{
        static const char header[] = {
                0xff, 0xff, 0xff, 0xff, 0xa5, 0x5a, 0xe7, 0x7e, 0x01
        };
        u8 *data = ts_data->rd_buf;

        if (memcmp(header, data, sizeof(header)))
                dev_err(&ts_data->spi->dev,
                        "%s header error: %*ph, ignoring...\n",
                        __func__, (int)sizeof(header), data);

        switch (data[9]) {
        case SURFACE3_REPORT_TOUCH:
                surface3_spi_process_touch(ts_data, data);
                break;
        case SURFACE3_REPORT_PEN:
                surface3_spi_process_pen(ts_data, data);
                break;
        default:
                dev_err(&ts_data->spi->dev,
                        "%s unknown packet type: %x, ignoring...\n",
                        __func__, data[9]);
                break;
        }
}

static irqreturn_t surface3_spi_irq_handler(int irq, void *dev_id)
{
        struct surface3_ts_data *data = dev_id;

        if (surface3_spi_read(data))
                return IRQ_HANDLED;

        dev_dbg(&data->spi->dev, "%s received -> %*ph\n",
                __func__, SURFACE3_PACKET_SIZE, data->rd_buf);
        surface3_spi_process(data);

        return IRQ_HANDLED;
}

static void surface3_spi_power(struct surface3_ts_data *data, bool on)
{
        gpiod_set_value(data->gpiod_rst[0], on);
        gpiod_set_value(data->gpiod_rst[1], on);
        /* let the device settle a little */
        msleep(20);
}

/**
 * surface3_spi_get_gpio_config - Get GPIO config from ACPI/DT
 *
 * @data: surface3_spi_ts_data pointer
 */
static int surface3_spi_get_gpio_config(struct surface3_ts_data *data)
{
        struct device *dev;
        struct gpio_desc *gpiod;
        int i;

        dev = &data->spi->dev;

        /* Get the reset lines GPIO pin number */
        for (i = 0; i < 2; i++) {
                gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_OUT_LOW);
                if (IS_ERR(gpiod))
                        return dev_err_probe(dev, PTR_ERR(gpiod),
                                             "Failed to get power GPIO %d\n", i);

                data->gpiod_rst[i] = gpiod;
        }

        return 0;
}

static int surface3_spi_create_touch_input(struct surface3_ts_data *data)
{
        struct input_dev *input;
        int error;

        input = devm_input_allocate_device(&data->spi->dev);
        if (!input)
                return -ENOMEM;

        data->input_dev = input;

        input_set_abs_params(input, ABS_MT_POSITION_X, 0, 9600, 0, 0);
        input_abs_set_res(input, ABS_MT_POSITION_X, 40);
        input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 7200, 0, 0);
        input_abs_set_res(input, ABS_MT_POSITION_Y, 48);
        input_set_abs_params(input, ABS_MT_WIDTH_MAJOR, 0, 1024, 0, 0);
        input_set_abs_params(input, ABS_MT_WIDTH_MINOR, 0, 1024, 0, 0);
        input_mt_init_slots(input, 10, INPUT_MT_DIRECT);

        input->name = "Surface3 SPI Capacitive TouchScreen";
        input->phys = "input/ts";
        input->id.bustype = BUS_SPI;
        input->id.vendor = 0x045e;      /* Microsoft */
        input->id.product = 0x0001;
        input->id.version = 0x0000;

        error = input_register_device(input);
        if (error) {
                dev_err(&data->spi->dev,
                        "Failed to register input device: %d", error);
                return error;
        }

        return 0;
}

static int surface3_spi_create_pen_input(struct surface3_ts_data *data)
{
        struct input_dev *input;
        int error;

        input = devm_input_allocate_device(&data->spi->dev);
        if (!input)
                return -ENOMEM;

        data->pen_input_dev = input;
        data->pen_tool = BTN_TOOL_PEN;

        __set_bit(INPUT_PROP_DIRECT, input->propbit);
        __set_bit(INPUT_PROP_POINTER, input->propbit);
        input_set_abs_params(input, ABS_X, 0, 9600, 0, 0);
        input_abs_set_res(input, ABS_X, 40);
        input_set_abs_params(input, ABS_Y, 0, 7200, 0, 0);
        input_abs_set_res(input, ABS_Y, 48);
        input_set_abs_params(input, ABS_PRESSURE, 0, 1024, 0, 0);
        input_set_capability(input, EV_KEY, BTN_TOUCH);
        input_set_capability(input, EV_KEY, BTN_STYLUS);
        input_set_capability(input, EV_KEY, BTN_TOOL_PEN);
        input_set_capability(input, EV_KEY, BTN_TOOL_RUBBER);

        input->name = "Surface3 SPI Pen Input";
        input->phys = "input/ts";
        input->id.bustype = BUS_SPI;
        input->id.vendor = 0x045e;     /* Microsoft */
        input->id.product = 0x0002;
        input->id.version = 0x0000;

        error = input_register_device(input);
        if (error) {
                dev_err(&data->spi->dev,
                        "Failed to register input device: %d", error);
                return error;
        }

        return 0;
}

static int surface3_spi_probe(struct spi_device *spi)
{
        struct surface3_ts_data *data;
        int error;

        /* Set up SPI*/
        spi->bits_per_word = 8;
        spi->mode = SPI_MODE_0;
        error = spi_setup(spi);
        if (error)
                return error;

        data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->spi = spi;
        spi_set_drvdata(spi, data);

        error = surface3_spi_get_gpio_config(data);
        if (error)
                return error;

        surface3_spi_power(data, true);
        surface3_spi_power(data, false);
        surface3_spi_power(data, true);

        error = surface3_spi_create_touch_input(data);
        if (error)
                return error;

        error = surface3_spi_create_pen_input(data);
        if (error)
                return error;

        error = devm_request_threaded_irq(&spi->dev, spi->irq,
                                          NULL, surface3_spi_irq_handler,
                                          IRQF_ONESHOT,
                                          "Surface3-irq", data);
        if (error)
                return error;

        return 0;
}

static int surface3_spi_suspend(struct device *dev)
{
        struct spi_device *spi = to_spi_device(dev);
        struct surface3_ts_data *data = spi_get_drvdata(spi);

        disable_irq(data->spi->irq);

        surface3_spi_power(data, false);

        return 0;
}

static int surface3_spi_resume(struct device *dev)
{
        struct spi_device *spi = to_spi_device(dev);
        struct surface3_ts_data *data = spi_get_drvdata(spi);

        surface3_spi_power(data, true);

        enable_irq(data->spi->irq);

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(surface3_spi_pm_ops,
                                surface3_spi_suspend,
                                surface3_spi_resume);

#ifdef CONFIG_ACPI
static const struct acpi_device_id surface3_spi_acpi_match[] = {
        { "MSHW0037", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, surface3_spi_acpi_match);
#endif

static struct spi_driver surface3_spi_driver = {
        .driver = {
                .name   = "Surface3-spi",
                .acpi_match_table = ACPI_PTR(surface3_spi_acpi_match),
                .pm = pm_sleep_ptr(&surface3_spi_pm_ops),
        },
        .probe = surface3_spi_probe,
};

module_spi_driver(surface3_spi_driver);

MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
MODULE_DESCRIPTION("Surface 3 SPI touchscreen driver");
MODULE_LICENSE("GPL v2");