// SPDX-License-Identifier: GPL-2.0
/*
 * ST1232 Touchscreen Controller Driver
 *
 * Copyright (C) 2010 Renesas Solutions Corp.
 *      Tony SIM <chinyeow.sim.xt@renesas.com>
 *
 * Using code from:
 *  - android.git.kernel.org: projects/kernel/common.git: synaptics_i2c_rmi.c
 *      Copyright (C) 2007 Google, Inc.
 */

#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/pm_qos.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/input/touch-overlay.h>

#define ST1232_TS_NAME  "st1232-ts"
#define ST1633_TS_NAME  "st1633-ts"

#define REG_STATUS              0x01    /* Device Status | Error Code */

#define STATUS_NORMAL           0x00
#define STATUS_INIT             0x01
#define STATUS_ERROR            0x02
#define STATUS_AUTO_TUNING      0x03
#define STATUS_IDLE             0x04
#define STATUS_POWER_DOWN       0x05

#define ERROR_NONE              0x00
#define ERROR_INVALID_ADDRESS   0x10
#define ERROR_INVALID_VALUE     0x20
#define ERROR_INVALID_PLATFORM  0x30

#define REG_XY_RESOLUTION       0x04
#define REG_XY_COORDINATES      0x12
#define ST_TS_MAX_FINGERS       10

struct st_chip_info {
        bool    have_z;
        u16     max_area;
        u16     max_fingers;
};

struct st1232_ts_data {
        struct i2c_client *client;
        struct input_dev *input_dev;
        struct touchscreen_properties prop;
        struct dev_pm_qos_request low_latency_req;
        struct gpio_desc *reset_gpio;
        const struct st_chip_info *chip_info;
        struct list_head touch_overlay_list;
        int read_buf_len;
        u8 *read_buf;
};

static int st1232_ts_read_data(struct st1232_ts_data *ts, u8 reg,
                               unsigned int n)
{
        struct i2c_client *client = ts->client;
        struct i2c_msg msg[] = {
                {
                        .addr   = client->addr,
                        .len    = sizeof(reg),
                        .buf    = &reg,
                },
                {
                        .addr   = client->addr,
                        .flags  = I2C_M_RD | I2C_M_DMA_SAFE,
                        .len    = n,
                        .buf    = ts->read_buf,
                }
        };
        int ret;

        ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
        if (ret != ARRAY_SIZE(msg))
                return ret < 0 ? ret : -EIO;

        return 0;
}

static int st1232_ts_wait_ready(struct st1232_ts_data *ts)
{
        unsigned int retries;
        int error;

        for (retries = 100; retries; retries--) {
                error = st1232_ts_read_data(ts, REG_STATUS, 1);
                if (!error) {
                        switch (ts->read_buf[0]) {
                        case STATUS_NORMAL | ERROR_NONE:
                        case STATUS_IDLE | ERROR_NONE:
                                return 0;
                        }
                }

                usleep_range(1000, 2000);
        }

        return -ENXIO;
}

static int st1232_ts_read_resolution(struct st1232_ts_data *ts, u16 *max_x,
                                     u16 *max_y)
{
        u8 *buf;
        int error;

        /* select resolution register */
        error = st1232_ts_read_data(ts, REG_XY_RESOLUTION, 3);
        if (error)
                return error;

        buf = ts->read_buf;

        *max_x = (((buf[0] & 0x0070) << 4) | buf[1]) - 1;
        *max_y = (((buf[0] & 0x0007) << 8) | buf[2]) - 1;

        return 0;
}

static int st1232_ts_parse_and_report(struct st1232_ts_data *ts)
{
        struct input_dev *input = ts->input_dev;
        struct input_mt_pos pos[ST_TS_MAX_FINGERS];
        u8 z[ST_TS_MAX_FINGERS];
        int slots[ST_TS_MAX_FINGERS];
        int n_contacts = 0;
        int i;

        for (i = 0; i < ts->chip_info->max_fingers; i++) {
                u8 *buf = &ts->read_buf[i * 4];

                if (buf[0] & BIT(7)) {
                        unsigned int x = ((buf[0] & 0x70) << 4) | buf[1];
                        unsigned int y = ((buf[0] & 0x07) << 8) | buf[2];

                        touchscreen_set_mt_pos(&pos[n_contacts],
                                               &ts->prop, x, y);

                        /* st1232 includes a z-axis / touch strength */
                        if (ts->chip_info->have_z)
                                z[n_contacts] = ts->read_buf[i + 6];

                        n_contacts++;
                }
        }

        input_mt_assign_slots(input, slots, pos, n_contacts, 0);
        for (i = 0; i < n_contacts; i++) {
                if (touch_overlay_process_contact(&ts->touch_overlay_list,
                                                  input, &pos[i], slots[i]))
                        continue;

                input_mt_slot(input, slots[i]);
                input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
                input_report_abs(input, ABS_MT_POSITION_X, pos[i].x);
                input_report_abs(input, ABS_MT_POSITION_Y, pos[i].y);
                if (ts->chip_info->have_z)
                        input_report_abs(input, ABS_MT_TOUCH_MAJOR, z[i]);
        }

        touch_overlay_sync_frame(&ts->touch_overlay_list, input);
        input_mt_sync_frame(input);
        input_sync(input);

        return n_contacts;
}

static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
{
        struct st1232_ts_data *ts = dev_id;
        int count;
        int error;

        error = st1232_ts_read_data(ts, REG_XY_COORDINATES, ts->read_buf_len);
        if (error)
                goto out;

        count = st1232_ts_parse_and_report(ts);
        if (!count) {
                if (ts->low_latency_req.dev) {
                        dev_pm_qos_remove_request(&ts->low_latency_req);
                        ts->low_latency_req.dev = NULL;
                }
        } else if (!ts->low_latency_req.dev) {
                /* First contact, request 100 us latency. */
                dev_pm_qos_add_ancestor_request(&ts->client->dev,
                                                &ts->low_latency_req,
                                                DEV_PM_QOS_RESUME_LATENCY, 100);
        }

out:
        return IRQ_HANDLED;
}

static void st1232_ts_power(struct st1232_ts_data *ts, bool poweron)
{
        if (ts->reset_gpio)
                gpiod_set_value_cansleep(ts->reset_gpio, !poweron);
}

static void st1232_ts_power_off(void *data)
{
        st1232_ts_power(data, false);
}

static const struct st_chip_info st1232_chip_info = {
        .have_z         = true,
        .max_area       = 0xff,
        .max_fingers    = 2,
};

static const struct st_chip_info st1633_chip_info = {
        .have_z         = false,
        .max_area       = 0x00,
        .max_fingers    = 5,
};

static int st1232_ts_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        const struct st_chip_info *match;
        struct st1232_ts_data *ts;
        struct input_dev *input_dev;
        u16 max_x, max_y;
        int error;

        match = device_get_match_data(&client->dev);
        if (!match && id)
                match = (const void *)id->driver_data;
        if (!match) {
                dev_err(&client->dev, "unknown device model\n");
                return -ENODEV;
        }

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                dev_err(&client->dev, "need I2C_FUNC_I2C\n");
                return -EIO;
        }

        if (!client->irq) {
                dev_err(&client->dev, "no IRQ?\n");
                return -EINVAL;
        }

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

        ts->chip_info = match;

        /* allocate a buffer according to the number of registers to read */
        ts->read_buf_len = ts->chip_info->max_fingers * 4;
        ts->read_buf = devm_kzalloc(&client->dev, ts->read_buf_len, GFP_KERNEL);
        if (!ts->read_buf)
                return -ENOMEM;

        input_dev = devm_input_allocate_device(&client->dev);
        if (!input_dev)
                return -ENOMEM;

        ts->client = client;
        ts->input_dev = input_dev;

        ts->reset_gpio = devm_gpiod_get_optional(&client->dev, NULL,
                                                 GPIOD_OUT_HIGH);
        if (IS_ERR(ts->reset_gpio)) {
                error = PTR_ERR(ts->reset_gpio);
                dev_err(&client->dev, "Unable to request GPIO pin: %d.\n",
                        error);
                return error;
        }

        st1232_ts_power(ts, true);

        error = devm_add_action_or_reset(&client->dev, st1232_ts_power_off, ts);
        if (error) {
                dev_err(&client->dev,
                        "Failed to install power off action: %d\n", error);
                return error;
        }

        input_dev->name = "st1232-touchscreen";
        input_dev->id.bustype = BUS_I2C;

        /* Wait until device is ready */
        error = st1232_ts_wait_ready(ts);
        if (error)
                return error;

        if (ts->chip_info->have_z)
                input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
                                     ts->chip_info->max_area, 0, 0);

        /* map overlay objects if defined in the device tree */
        INIT_LIST_HEAD(&ts->touch_overlay_list);
        error = touch_overlay_map(&ts->touch_overlay_list, input_dev);
        if (error)
                return error;

        if (touch_overlay_mapped_touchscreen(&ts->touch_overlay_list)) {
                /* Read resolution from the overlay touchscreen if defined */
                touch_overlay_get_touchscreen_abs(&ts->touch_overlay_list,
                                                  &max_x, &max_y);
        } else {
                /* Read resolution from the chip */
                error = st1232_ts_read_resolution(ts, &max_x, &max_y);
                if (error) {
                        dev_err(&client->dev,
                                "Failed to read resolution: %d\n", error);
                        return error;
                }
        }

        input_set_abs_params(input_dev, ABS_MT_POSITION_X,
                             0, max_x, 0, 0);
        input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
                             0, max_y, 0, 0);

        touchscreen_parse_properties(input_dev, true, &ts->prop);

        error = input_mt_init_slots(input_dev, ts->chip_info->max_fingers,
                                    INPUT_MT_DIRECT | INPUT_MT_TRACK |
                                        INPUT_MT_DROP_UNUSED);
        if (error) {
                dev_err(&client->dev, "failed to initialize MT slots\n");
                return error;
        }

        error = devm_request_threaded_irq(&client->dev, client->irq,
                                          NULL, st1232_ts_irq_handler,
                                          IRQF_ONESHOT,
                                          client->name, ts);
        if (error) {
                dev_err(&client->dev, "Failed to register interrupt\n");
                return error;
        }

        error = input_register_device(ts->input_dev);
        if (error) {
                dev_err(&client->dev, "Unable to register %s input device\n",
                        input_dev->name);
                return error;
        }

        i2c_set_clientdata(client, ts);

        return 0;
}

static int st1232_ts_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct st1232_ts_data *ts = i2c_get_clientdata(client);

        disable_irq(client->irq);

        if (!device_may_wakeup(&client->dev))
                st1232_ts_power(ts, false);

        return 0;
}

static int st1232_ts_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct st1232_ts_data *ts = i2c_get_clientdata(client);

        if (!device_may_wakeup(&client->dev))
                st1232_ts_power(ts, true);

        enable_irq(client->irq);

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(st1232_ts_pm_ops,
                                st1232_ts_suspend, st1232_ts_resume);

static const struct i2c_device_id st1232_ts_id[] = {
        { ST1232_TS_NAME, (unsigned long)&st1232_chip_info },
        { ST1633_TS_NAME, (unsigned long)&st1633_chip_info },
        { }
};
MODULE_DEVICE_TABLE(i2c, st1232_ts_id);

static const struct of_device_id st1232_ts_dt_ids[] = {
        { .compatible = "sitronix,st1232", .data = &st1232_chip_info },
        { .compatible = "sitronix,st1633", .data = &st1633_chip_info },
        { }
};
MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);

static struct i2c_driver st1232_ts_driver = {
        .probe          = st1232_ts_probe,
        .id_table       = st1232_ts_id,
        .driver = {
                .name   = ST1232_TS_NAME,
                .of_match_table = st1232_ts_dt_ids,
                .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
                .pm     = pm_sleep_ptr(&st1232_ts_pm_ops),
        },
};

module_i2c_driver(st1232_ts_driver);

MODULE_AUTHOR("Tony SIM <chinyeow.sim.xt@renesas.com>");
MODULE_AUTHOR("Martin Kepplinger <martin.kepplinger@ginzinger.com>");
MODULE_DESCRIPTION("SITRONIX ST1232 Touchscreen Controller Driver");
MODULE_LICENSE("GPL v2");