// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Pixcir I2C touchscreen controllers.
 *
 * Copyright (C) 2010-2011 Pixcir, Inc.
 */

#include <linux/unaligned.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/input/touchscreen.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>

#define PIXCIR_MAX_SLOTS       5 /* Max fingers supported by driver */

/*
 * Register map
 */
#define PIXCIR_REG_POWER_MODE   51
#define PIXCIR_REG_INT_MODE     52

/*
 * Power modes:
 * active: max scan speed
 * idle: lower scan speed with automatic transition to active on touch
 * halt: datasheet says sleep but this is more like halt as the chip
 *       clocks are cut and it can only be brought out of this mode
 *       using the RESET pin.
 */
enum pixcir_power_mode {
        PIXCIR_POWER_ACTIVE,
        PIXCIR_POWER_IDLE,
        PIXCIR_POWER_HALT,
};

#define PIXCIR_POWER_MODE_MASK  0x03
#define PIXCIR_POWER_ALLOW_IDLE (1UL << 2)

/*
 * Interrupt modes:
 * periodical: interrupt is asserted periodically
 * diff coordinates: interrupt is asserted when coordinates change
 * level on touch: interrupt level asserted during touch
 * pulse on touch: interrupt pulse asserted during touch
 *
 */
enum pixcir_int_mode {
        PIXCIR_INT_PERIODICAL,
        PIXCIR_INT_DIFF_COORD,
        PIXCIR_INT_LEVEL_TOUCH,
        PIXCIR_INT_PULSE_TOUCH,
};

#define PIXCIR_INT_MODE_MASK    0x03
#define PIXCIR_INT_ENABLE       (1UL << 3)
#define PIXCIR_INT_POL_HIGH     (1UL << 2)

/**
 * struct pixcir_i2c_chip_data - chip related data
 * @max_fingers:        Max number of fingers reported simultaneously by h/w
 * @has_hw_ids:         Hardware supports finger tracking IDs
 *
 */
struct pixcir_i2c_chip_data {
        u8 max_fingers;
        bool has_hw_ids;
};

struct pixcir_i2c_ts_data {
        struct i2c_client *client;
        struct input_dev *input;
        struct gpio_desc *gpio_attb;
        struct gpio_desc *gpio_reset;
        struct gpio_desc *gpio_enable;
        struct gpio_desc *gpio_wake;
        const struct pixcir_i2c_chip_data *chip;
        struct touchscreen_properties prop;
        bool running;
};

struct pixcir_report_data {
        int num_touches;
        struct input_mt_pos pos[PIXCIR_MAX_SLOTS];
        int ids[PIXCIR_MAX_SLOTS];
};

static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
                            struct pixcir_report_data *report)
{
        u8 rdbuf[2 + PIXCIR_MAX_SLOTS * 5];
        u8 wrbuf[1] = { 0 };
        u8 *bufptr;
        u8 touch;
        int ret, i;
        int readsize;
        const struct pixcir_i2c_chip_data *chip = tsdata->chip;

        memset(report, 0, sizeof(struct pixcir_report_data));

        i = chip->has_hw_ids ? 1 : 0;
        readsize = 2 + tsdata->chip->max_fingers * (4 + i);
        if (readsize > sizeof(rdbuf))
                readsize = sizeof(rdbuf);

        ret = i2c_master_send(tsdata->client, wrbuf, sizeof(wrbuf));
        if (ret != sizeof(wrbuf)) {
                dev_err(&tsdata->client->dev,
                        "%s: i2c_master_send failed(), ret=%d\n",
                        __func__, ret);
                return;
        }

        ret = i2c_master_recv(tsdata->client, rdbuf, readsize);
        if (ret != readsize) {
                dev_err(&tsdata->client->dev,
                        "%s: i2c_master_recv failed(), ret=%d\n",
                        __func__, ret);
                return;
        }

        touch = rdbuf[0] & 0x7;
        if (touch > tsdata->chip->max_fingers)
                touch = tsdata->chip->max_fingers;

        report->num_touches = touch;
        bufptr = &rdbuf[2];

        for (i = 0; i < touch; i++) {
                touchscreen_set_mt_pos(&report->pos[i], &tsdata->prop,
                                       get_unaligned_le16(bufptr),
                                       get_unaligned_le16(bufptr + 2));
                if (chip->has_hw_ids) {
                        report->ids[i] = bufptr[4];
                        bufptr = bufptr + 5;
                } else {
                        bufptr = bufptr + 4;
                }
        }
}

static void pixcir_ts_report(struct pixcir_i2c_ts_data *ts,
                             struct pixcir_report_data *report)
{
        int slots[PIXCIR_MAX_SLOTS];
        int n, i, slot;
        struct device *dev = &ts->client->dev;
        const struct pixcir_i2c_chip_data *chip = ts->chip;

        n = report->num_touches;
        if (n > PIXCIR_MAX_SLOTS)
                n = PIXCIR_MAX_SLOTS;

        if (!ts->chip->has_hw_ids)
                input_mt_assign_slots(ts->input, slots, report->pos, n, 0);

        for (i = 0; i < n; i++) {
                if (chip->has_hw_ids) {
                        slot = input_mt_get_slot_by_key(ts->input,
                                                        report->ids[i]);
                        if (slot < 0) {
                                dev_dbg(dev, "no free slot for id 0x%x\n",
                                        report->ids[i]);
                                continue;
                        }
                } else {
                        slot = slots[i];
                }

                input_mt_slot(ts->input, slot);
                input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);

                input_report_abs(ts->input, ABS_MT_POSITION_X,
                                 report->pos[i].x);
                input_report_abs(ts->input, ABS_MT_POSITION_Y,
                                 report->pos[i].y);

                dev_dbg(dev, "%d: slot %d, x %d, y %d\n",
                        i, slot, report->pos[i].x, report->pos[i].y);
        }

        input_mt_sync_frame(ts->input);
        input_sync(ts->input);
}

static irqreturn_t pixcir_ts_isr(int irq, void *dev_id)
{
        struct pixcir_i2c_ts_data *tsdata = dev_id;
        struct pixcir_report_data report;

        while (tsdata->running) {
                /* parse packet */
                pixcir_ts_parse(tsdata, &report);

                /* report it */
                pixcir_ts_report(tsdata, &report);

                if (gpiod_get_value_cansleep(tsdata->gpio_attb)) {
                        if (report.num_touches) {
                                /*
                                 * Last report with no finger up?
                                 * Do it now then.
                                 */
                                input_mt_sync_frame(tsdata->input);
                                input_sync(tsdata->input);
                        }
                        break;
                }

                msleep(20);
        }

        return IRQ_HANDLED;
}

static void pixcir_reset(struct pixcir_i2c_ts_data *tsdata)
{
        if (!IS_ERR_OR_NULL(tsdata->gpio_reset)) {
                gpiod_set_value_cansleep(tsdata->gpio_reset, 1);
                ndelay(100);    /* datasheet section 1.2.3 says 80ns min. */
                gpiod_set_value_cansleep(tsdata->gpio_reset, 0);
                /* wait for controller ready. 100ms guess. */
                msleep(100);
        }
}

static int pixcir_set_power_mode(struct pixcir_i2c_ts_data *ts,
                                 enum pixcir_power_mode mode)
{
        struct device *dev = &ts->client->dev;
        int ret;

        if (mode == PIXCIR_POWER_ACTIVE || mode == PIXCIR_POWER_IDLE) {
                if (ts->gpio_wake)
                        gpiod_set_value_cansleep(ts->gpio_wake, 1);
        }

        ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_POWER_MODE);
        if (ret < 0) {
                dev_err(dev, "%s: can't read reg %d : %d\n",
                        __func__, PIXCIR_REG_POWER_MODE, ret);
                return ret;
        }

        ret &= ~PIXCIR_POWER_MODE_MASK;
        ret |= mode;

        /* Always AUTO_IDLE */
        ret |= PIXCIR_POWER_ALLOW_IDLE;

        ret = i2c_smbus_write_byte_data(ts->client, PIXCIR_REG_POWER_MODE, ret);
        if (ret < 0) {
                dev_err(dev, "%s: can't write reg %d : %d\n",
                        __func__, PIXCIR_REG_POWER_MODE, ret);
                return ret;
        }

        if (mode == PIXCIR_POWER_HALT) {
                if (ts->gpio_wake)
                        gpiod_set_value_cansleep(ts->gpio_wake, 0);
        }

        return 0;
}

/*
 * Set the interrupt mode for the device i.e. ATTB line behaviour
 *
 * @polarity : 1 for active high, 0 for active low.
 */
static int pixcir_set_int_mode(struct pixcir_i2c_ts_data *ts,
                               enum pixcir_int_mode mode, bool polarity)
{
        struct device *dev = &ts->client->dev;
        int ret;

        ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_INT_MODE);
        if (ret < 0) {
                dev_err(dev, "%s: can't read reg %d : %d\n",
                        __func__, PIXCIR_REG_INT_MODE, ret);
                return ret;
        }

        ret &= ~PIXCIR_INT_MODE_MASK;
        ret |= mode;

        if (polarity)
                ret |= PIXCIR_INT_POL_HIGH;
        else
                ret &= ~PIXCIR_INT_POL_HIGH;

        ret = i2c_smbus_write_byte_data(ts->client, PIXCIR_REG_INT_MODE, ret);
        if (ret < 0) {
                dev_err(dev, "%s: can't write reg %d : %d\n",
                        __func__, PIXCIR_REG_INT_MODE, ret);
                return ret;
        }

        return 0;
}

/*
 * Enable/disable interrupt generation
 */
static int pixcir_int_enable(struct pixcir_i2c_ts_data *ts, bool enable)
{
        struct device *dev = &ts->client->dev;
        int ret;

        ret = i2c_smbus_read_byte_data(ts->client, PIXCIR_REG_INT_MODE);
        if (ret < 0) {
                dev_err(dev, "%s: can't read reg %d : %d\n",
                        __func__, PIXCIR_REG_INT_MODE, ret);
                return ret;
        }

        if (enable)
                ret |= PIXCIR_INT_ENABLE;
        else
                ret &= ~PIXCIR_INT_ENABLE;

        ret = i2c_smbus_write_byte_data(ts->client, PIXCIR_REG_INT_MODE, ret);
        if (ret < 0) {
                dev_err(dev, "%s: can't write reg %d : %d\n",
                        __func__, PIXCIR_REG_INT_MODE, ret);
                return ret;
        }

        return 0;
}

static int pixcir_start(struct pixcir_i2c_ts_data *ts)
{
        struct device *dev = &ts->client->dev;
        int error;

        if (ts->gpio_enable) {
                gpiod_set_value_cansleep(ts->gpio_enable, 1);
                msleep(100);
        }

        /* LEVEL_TOUCH interrupt with active low polarity */
        error = pixcir_set_int_mode(ts, PIXCIR_INT_LEVEL_TOUCH, 0);
        if (error) {
                dev_err(dev, "Failed to set interrupt mode: %d\n", error);
                return error;
        }

        ts->running = true;
        mb();   /* Update status before IRQ can fire */

        /* enable interrupt generation */
        error = pixcir_int_enable(ts, true);
        if (error) {
                dev_err(dev, "Failed to enable interrupt generation: %d\n",
                        error);
                return error;
        }

        return 0;
}

static int pixcir_stop(struct pixcir_i2c_ts_data *ts)
{
        int error;

        /* Disable interrupt generation */
        error = pixcir_int_enable(ts, false);
        if (error) {
                dev_err(&ts->client->dev,
                        "Failed to disable interrupt generation: %d\n",
                        error);
                return error;
        }

        /* Exit ISR if running, no more report parsing */
        ts->running = false;
        mb();   /* update status before we synchronize irq */

        /* Wait till running ISR is complete */
        synchronize_irq(ts->client->irq);

        if (ts->gpio_enable)
                gpiod_set_value_cansleep(ts->gpio_enable, 0);

        return 0;
}

static int pixcir_input_open(struct input_dev *dev)
{
        struct pixcir_i2c_ts_data *ts = input_get_drvdata(dev);

        return pixcir_start(ts);
}

static void pixcir_input_close(struct input_dev *dev)
{
        struct pixcir_i2c_ts_data *ts = input_get_drvdata(dev);

        pixcir_stop(ts);
}

static int pixcir_i2c_ts_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct pixcir_i2c_ts_data *ts = i2c_get_clientdata(client);
        struct input_dev *input = ts->input;
        int error;

        guard(mutex)(&input->mutex);

        if (device_may_wakeup(&client->dev)) {
                if (!input_device_enabled(input)) {
                        error = pixcir_start(ts);
                        if (error) {
                                dev_err(dev, "Failed to start\n");
                                return error;
                        }
                }
        } else if (input_device_enabled(input)) {
                error = pixcir_stop(ts);
                if (error)
                        return error;
        }

        return 0;
}

static int pixcir_i2c_ts_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct pixcir_i2c_ts_data *ts = i2c_get_clientdata(client);
        struct input_dev *input = ts->input;
        int error;

        guard(mutex)(&input->mutex);

        if (device_may_wakeup(&client->dev)) {
                if (!input_device_enabled(input)) {
                        error = pixcir_stop(ts);
                        if (error) {
                                dev_err(dev, "Failed to stop\n");
                                return error;
                        }
                }
        } else if (input_device_enabled(input)) {
                error = pixcir_start(ts);
                if (error)
                        return error;
        }

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(pixcir_dev_pm_ops,
                                pixcir_i2c_ts_suspend, pixcir_i2c_ts_resume);

static int pixcir_i2c_ts_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct device *dev = &client->dev;
        struct pixcir_i2c_ts_data *tsdata;
        struct input_dev *input;
        int error;

        tsdata = devm_kzalloc(dev, sizeof(*tsdata), GFP_KERNEL);
        if (!tsdata)
                return -ENOMEM;

        tsdata->chip = device_get_match_data(dev);
        if (!tsdata->chip && id)
                tsdata->chip = (const void *)id->driver_data;
        if (!tsdata->chip) {
                dev_err(dev, "can't locate chip data\n");
                return -EINVAL;
        }

        input = devm_input_allocate_device(dev);
        if (!input) {
                dev_err(dev, "Failed to allocate input device\n");
                return -ENOMEM;
        }

        tsdata->client = client;
        tsdata->input = input;

        input->name = client->name;
        input->id.bustype = BUS_I2C;
        input->open = pixcir_input_open;
        input->close = pixcir_input_close;

        input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
        input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
        touchscreen_parse_properties(input, true, &tsdata->prop);
        if (!input_abs_get_max(input, ABS_MT_POSITION_X) ||
            !input_abs_get_max(input, ABS_MT_POSITION_Y)) {
                dev_err(dev, "Touchscreen size is not specified\n");
                return -EINVAL;
        }

        error = input_mt_init_slots(input, tsdata->chip->max_fingers,
                                    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
        if (error) {
                dev_err(dev, "Error initializing Multi-Touch slots\n");
                return error;
        }

        input_set_drvdata(input, tsdata);

        tsdata->gpio_attb = devm_gpiod_get(dev, "attb", GPIOD_IN);
        if (IS_ERR(tsdata->gpio_attb))
                return dev_err_probe(dev, PTR_ERR(tsdata->gpio_attb),
                                     "Failed to request ATTB gpio\n");

        tsdata->gpio_reset = devm_gpiod_get_optional(dev, "reset",
                                                     GPIOD_OUT_LOW);
        if (IS_ERR(tsdata->gpio_reset))
                return dev_err_probe(dev, PTR_ERR(tsdata->gpio_reset),
                                     "Failed to request RESET gpio\n");

        tsdata->gpio_wake = devm_gpiod_get_optional(dev, "wake",
                                                    GPIOD_OUT_HIGH);
        if (IS_ERR(tsdata->gpio_wake))
                return dev_err_probe(dev, PTR_ERR(tsdata->gpio_wake),
                                     "Failed to get wake gpio\n");

        tsdata->gpio_enable = devm_gpiod_get_optional(dev, "enable",
                                                      GPIOD_OUT_HIGH);
        if (IS_ERR(tsdata->gpio_enable))
                return dev_err_probe(dev, PTR_ERR(tsdata->gpio_enable),
                                     "Failed to get enable gpio\n");

        if (tsdata->gpio_enable)
                msleep(100);

        error = devm_request_threaded_irq(dev, client->irq, NULL, pixcir_ts_isr,
                                          IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                                          client->name, tsdata);
        if (error) {
                dev_err(dev, "failed to request irq %d\n", client->irq);
                return error;
        }

        pixcir_reset(tsdata);

        /* Always be in IDLE mode to save power, device supports auto wake */
        error = pixcir_set_power_mode(tsdata, PIXCIR_POWER_IDLE);
        if (error) {
                dev_err(dev, "Failed to set IDLE mode\n");
                return error;
        }

        /* Stop device till opened */
        error = pixcir_stop(tsdata);
        if (error)
                return error;

        error = input_register_device(input);
        if (error)
                return error;

        i2c_set_clientdata(client, tsdata);

        return 0;
}

static const struct pixcir_i2c_chip_data pixcir_ts_data = {
        .max_fingers = 2,
        /* no hw id support */
};

static const struct pixcir_i2c_chip_data pixcir_tangoc_data = {
        .max_fingers = 5,
        .has_hw_ids = true,
};

static const struct i2c_device_id pixcir_i2c_ts_id[] = {
        { .name = "pixcir_ts", .driver_data = (unsigned long)&pixcir_ts_data },
        { .name = "pixcir_tangoc", .driver_data = (unsigned long)&pixcir_tangoc_data },
        { }
};
MODULE_DEVICE_TABLE(i2c, pixcir_i2c_ts_id);

#ifdef CONFIG_OF
static const struct of_device_id pixcir_of_match[] = {
        { .compatible = "pixcir,pixcir_ts", .data = &pixcir_ts_data },
        { .compatible = "pixcir,pixcir_tangoc", .data = &pixcir_tangoc_data },
        { }
};
MODULE_DEVICE_TABLE(of, pixcir_of_match);
#endif

static struct i2c_driver pixcir_i2c_ts_driver = {
        .driver = {
                .name   = "pixcir_ts",
                .pm     = pm_sleep_ptr(&pixcir_dev_pm_ops),
                .of_match_table = of_match_ptr(pixcir_of_match),
        },
        .probe          = pixcir_i2c_ts_probe,
        .id_table       = pixcir_i2c_ts_id,
};

module_i2c_driver(pixcir_i2c_ts_driver);

MODULE_AUTHOR("Jianchun Bian <jcbian@pixcir.com.cn>, Dequan Meng <dqmeng@pixcir.com.cn>");
MODULE_DESCRIPTION("Pixcir I2C Touchscreen Driver");
MODULE_LICENSE("GPL");