// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Semtech SX8654 I2C touchscreen controller.
 *
 * Copyright (c) 2015 Armadeus Systems
 *      Sébastien Szymanski <sebastien.szymanski@armadeus.com>
 *
 * Using code from:
 *  - sx865x.c
 *      Copyright (c) 2013 U-MoBo Srl
 *      Pierluigi Passaro <p.passaro@u-mobo.com>
 *  - sx8650.c
 *      Copyright (c) 2009 Wayne Roberts
 *  - tsc2007.c
 *      Copyright (c) 2008 Kwangwoo Lee
 *  - ads7846.c
 *      Copyright (c) 2005 David Brownell
 *      Copyright (c) 2006 Nokia Corporation
 *  - corgi_ts.c
 *      Copyright (C) 2004-2005 Richard Purdie
 *  - omap_ts.[hc], ads7846.h, ts_osk.c
 *      Copyright (C) 2002 MontaVista Software
 *      Copyright (C) 2004 Texas Instruments
 *      Copyright (C) 2005 Dirk Behme
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/touchscreen.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>

/* register addresses */
#define I2C_REG_TOUCH0                  0x00
#define I2C_REG_TOUCH1                  0x01
#define I2C_REG_CHANMASK                0x04
#define I2C_REG_IRQMASK                 0x22
#define I2C_REG_IRQSRC                  0x23
#define I2C_REG_SOFTRESET               0x3f

#define I2C_REG_SX8650_STAT             0x05
#define SX8650_STAT_CONVIRQ             BIT(7)

/* commands */
#define CMD_READ_REGISTER               0x40
#define CMD_PENTRG                      0xe0

/* value for I2C_REG_SOFTRESET */
#define SOFTRESET_VALUE                 0xde

/* bits for I2C_REG_IRQSRC */
#define IRQ_PENTOUCH_TOUCHCONVDONE      BIT(3)
#define IRQ_PENRELEASE                  BIT(2)

/* bits for RegTouch1 */
#define CONDIRQ                         0x20
#define RPDNT_100K                      0x00
#define FILT_7SA                        0x03

/* bits for I2C_REG_CHANMASK */
#define CONV_X                          BIT(7)
#define CONV_Y                          BIT(6)

/* coordinates rate: higher nibble of CTRL0 register */
#define RATE_MANUAL                     0x00
#define RATE_5000CPS                    0xf0

/* power delay: lower nibble of CTRL0 register */
#define POWDLY_1_1MS                    0x0b

/* for sx8650, as we have no pen release IRQ there: timeout in ns following the
 * last PENIRQ after which we assume the pen is lifted.
 */
#define SX8650_PENIRQ_TIMEOUT           msecs_to_jiffies(10)

#define MAX_12BIT                       ((1 << 12) - 1)
#define MAX_I2C_READ_LEN                10 /* see datasheet section 5.1.5 */

/* channel definition */
#define CH_X                            0x00
#define CH_Y                            0x01

struct sx865x_data {
        u8 cmd_manual;
        u8 chan_mask;
        bool has_irq_penrelease;
        bool has_reg_irqmask;
        irq_handler_t irqh;
};

struct sx8654 {
        struct input_dev *input;
        struct i2c_client *client;
        struct gpio_desc *gpio_reset;

        spinlock_t lock;        /* for input reporting from irq/timer */
        struct timer_list timer;

        struct touchscreen_properties props;

        const struct sx865x_data *data;
};

static inline void sx865x_penrelease(struct sx8654 *ts)
{
        struct input_dev *input_dev = ts->input;

        input_report_key(input_dev, BTN_TOUCH, 0);
        input_sync(input_dev);
}

static void sx865x_penrelease_timer_handler(struct timer_list *t)
{
        struct sx8654 *ts = timer_container_of(ts, t, timer);
        unsigned long flags;

        spin_lock_irqsave(&ts->lock, flags);
        sx865x_penrelease(ts);
        spin_unlock_irqrestore(&ts->lock, flags);
        dev_dbg(&ts->client->dev, "penrelease by timer\n");
}

static irqreturn_t sx8650_irq(int irq, void *handle)
{
        struct sx8654 *ts = handle;
        struct device *dev = &ts->client->dev;
        int len, i;
        unsigned long flags;
        u8 stat;
        u16 x, y;
        u16 ch;
        u16 chdata;
        __be16 data[MAX_I2C_READ_LEN / sizeof(__be16)];
        u8 nchan = hweight32(ts->data->chan_mask);
        u8 readlen = nchan * sizeof(*data);

        stat = i2c_smbus_read_byte_data(ts->client, CMD_READ_REGISTER
                                                    | I2C_REG_SX8650_STAT);

        if (!(stat & SX8650_STAT_CONVIRQ)) {
                dev_dbg(dev, "%s ignore stat [0x%02x]", __func__, stat);
                return IRQ_HANDLED;
        }

        len = i2c_master_recv(ts->client, (u8 *)data, readlen);
        if (len != readlen) {
                dev_dbg(dev, "ignore short recv (%d)\n", len);
                return IRQ_HANDLED;
        }

        spin_lock_irqsave(&ts->lock, flags);

        x = 0;
        y = 0;
        for (i = 0; i < nchan; i++) {
                chdata = be16_to_cpu(data[i]);

                if (unlikely(chdata == 0xFFFF)) {
                        dev_dbg(dev, "invalid qualified data @ %d\n", i);
                        continue;
                } else if (unlikely(chdata & 0x8000)) {
                        dev_warn(dev, "hibit @ %d [0x%04x]\n", i, chdata);
                        continue;
                }

                ch = chdata >> 12;
                if (ch == CH_X)
                        x = chdata & MAX_12BIT;
                else if (ch == CH_Y)
                        y = chdata & MAX_12BIT;
                else
                        dev_warn(dev, "unknown channel %d [0x%04x]\n", ch,
                                 chdata);
        }

        touchscreen_report_pos(ts->input, &ts->props, x, y, false);
        input_report_key(ts->input, BTN_TOUCH, 1);
        input_sync(ts->input);
        dev_dbg(dev, "point(%4d,%4d)\n", x, y);

        mod_timer(&ts->timer, jiffies + SX8650_PENIRQ_TIMEOUT);
        spin_unlock_irqrestore(&ts->lock, flags);

        return IRQ_HANDLED;
}

static irqreturn_t sx8654_irq(int irq, void *handle)
{
        struct sx8654 *sx8654 = handle;
        int irqsrc;
        u8 data[4];
        unsigned int x, y;
        int retval;

        irqsrc = i2c_smbus_read_byte_data(sx8654->client,
                                          CMD_READ_REGISTER | I2C_REG_IRQSRC);
        dev_dbg(&sx8654->client->dev, "irqsrc = 0x%x", irqsrc);

        if (irqsrc < 0)
                goto out;

        if (irqsrc & IRQ_PENRELEASE) {
                dev_dbg(&sx8654->client->dev, "pen release interrupt");

                input_report_key(sx8654->input, BTN_TOUCH, 0);
                input_sync(sx8654->input);
        }

        if (irqsrc & IRQ_PENTOUCH_TOUCHCONVDONE) {
                dev_dbg(&sx8654->client->dev, "pen touch interrupt");

                retval = i2c_master_recv(sx8654->client, data, sizeof(data));
                if (retval != sizeof(data))
                        goto out;

                /* invalid data */
                if (unlikely(data[0] & 0x80 || data[2] & 0x80))
                        goto out;

                x = ((data[0] & 0xf) << 8) | (data[1]);
                y = ((data[2] & 0xf) << 8) | (data[3]);

                touchscreen_report_pos(sx8654->input, &sx8654->props, x, y,
                                       false);
                input_report_key(sx8654->input, BTN_TOUCH, 1);
                input_sync(sx8654->input);

                dev_dbg(&sx8654->client->dev, "point(%4d,%4d)\n", x, y);
        }

out:
        return IRQ_HANDLED;
}

static int sx8654_reset(struct sx8654 *ts)
{
        int err;

        if (ts->gpio_reset) {
                gpiod_set_value_cansleep(ts->gpio_reset, 1);
                udelay(2); /* Tpulse > 1µs */
                gpiod_set_value_cansleep(ts->gpio_reset, 0);
        } else {
                dev_dbg(&ts->client->dev, "NRST unavailable, try softreset\n");
                err = i2c_smbus_write_byte_data(ts->client, I2C_REG_SOFTRESET,
                                                SOFTRESET_VALUE);
                if (err)
                        return err;
        }

        return 0;
}

static int sx8654_open(struct input_dev *dev)
{
        struct sx8654 *sx8654 = input_get_drvdata(dev);
        struct i2c_client *client = sx8654->client;
        int error;

        /* enable pen trigger mode */
        error = i2c_smbus_write_byte_data(client, I2C_REG_TOUCH0,
                                          RATE_5000CPS | POWDLY_1_1MS);
        if (error) {
                dev_err(&client->dev, "writing to I2C_REG_TOUCH0 failed");
                return error;
        }

        error = i2c_smbus_write_byte(client, CMD_PENTRG);
        if (error) {
                dev_err(&client->dev, "writing command CMD_PENTRG failed");
                return error;
        }

        enable_irq(client->irq);

        return 0;
}

static void sx8654_close(struct input_dev *dev)
{
        struct sx8654 *sx8654 = input_get_drvdata(dev);
        struct i2c_client *client = sx8654->client;
        int error;

        disable_irq(client->irq);

        if (!sx8654->data->has_irq_penrelease)
                timer_delete_sync(&sx8654->timer);

        /* enable manual mode mode */
        error = i2c_smbus_write_byte(client, sx8654->data->cmd_manual);
        if (error) {
                dev_err(&client->dev, "writing command CMD_MANUAL failed");
                return;
        }

        error = i2c_smbus_write_byte_data(client, I2C_REG_TOUCH0, RATE_MANUAL);
        if (error) {
                dev_err(&client->dev, "writing to I2C_REG_TOUCH0 failed");
                return;
        }
}

static int sx8654_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct sx8654 *sx8654;
        struct input_dev *input;
        int error;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_READ_WORD_DATA))
                return -ENXIO;

        sx8654 = devm_kzalloc(&client->dev, sizeof(*sx8654), GFP_KERNEL);
        if (!sx8654)
                return -ENOMEM;

        sx8654->gpio_reset = devm_gpiod_get_optional(&client->dev, "reset",
                                                     GPIOD_OUT_HIGH);
        if (IS_ERR(sx8654->gpio_reset))
                return dev_err_probe(&client->dev, PTR_ERR(sx8654->gpio_reset),
                                     "unable to get reset-gpio\n");
        dev_dbg(&client->dev, "got GPIO reset pin\n");

        sx8654->data = device_get_match_data(&client->dev);
        if (!sx8654->data)
                sx8654->data = (const struct sx865x_data *)id->driver_data;
        if (!sx8654->data) {
                dev_err(&client->dev, "invalid or missing device data\n");
                return -EINVAL;
        }

        if (!sx8654->data->has_irq_penrelease) {
                dev_dbg(&client->dev, "use timer for penrelease\n");
                timer_setup(&sx8654->timer, sx865x_penrelease_timer_handler, 0);
                spin_lock_init(&sx8654->lock);
        }

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

        input->name = "SX8654 I2C Touchscreen";
        input->id.bustype = BUS_I2C;
        input->dev.parent = &client->dev;
        input->open = sx8654_open;
        input->close = sx8654_close;

        __set_bit(INPUT_PROP_DIRECT, input->propbit);
        input_set_capability(input, EV_KEY, BTN_TOUCH);
        input_set_abs_params(input, ABS_X, 0, MAX_12BIT, 0, 0);
        input_set_abs_params(input, ABS_Y, 0, MAX_12BIT, 0, 0);

        touchscreen_parse_properties(input, false, &sx8654->props);

        sx8654->client = client;
        sx8654->input = input;

        input_set_drvdata(sx8654->input, sx8654);

        error = sx8654_reset(sx8654);
        if (error) {
                dev_err(&client->dev, "reset failed");
                return error;
        }

        error = i2c_smbus_write_byte_data(client, I2C_REG_CHANMASK,
                                          sx8654->data->chan_mask);
        if (error) {
                dev_err(&client->dev, "writing to I2C_REG_CHANMASK failed");
                return error;
        }

        if (sx8654->data->has_reg_irqmask) {
                error = i2c_smbus_write_byte_data(client, I2C_REG_IRQMASK,
                                                  IRQ_PENTOUCH_TOUCHCONVDONE |
                                                        IRQ_PENRELEASE);
                if (error) {
                        dev_err(&client->dev, "writing I2C_REG_IRQMASK failed");
                        return error;
                }
        }

        error = i2c_smbus_write_byte_data(client, I2C_REG_TOUCH1,
                                          CONDIRQ | RPDNT_100K | FILT_7SA);
        if (error) {
                dev_err(&client->dev, "writing to I2C_REG_TOUCH1 failed");
                return error;
        }

        error = devm_request_threaded_irq(&client->dev, client->irq,
                                          NULL, sx8654->data->irqh,
                                          IRQF_ONESHOT,
                                          client->name, sx8654);
        if (error) {
                dev_err(&client->dev,
                        "Failed to enable IRQ %d, error: %d\n",
                        client->irq, error);
                return error;
        }

        /* Disable the IRQ, we'll enable it in sx8654_open() */
        disable_irq(client->irq);

        error = input_register_device(sx8654->input);
        if (error)
                return error;

        return 0;
}

static const struct sx865x_data sx8650_data = {
        .cmd_manual             = 0xb0,
        .has_irq_penrelease     = false,
        .has_reg_irqmask        = false,
        .chan_mask              = (CONV_X | CONV_Y),
        .irqh                   = sx8650_irq,
};

static const struct sx865x_data sx8654_data = {
        .cmd_manual             = 0xc0,
        .has_irq_penrelease     = true,
        .has_reg_irqmask        = true,
        .chan_mask              = (CONV_X | CONV_Y),
        .irqh                   = sx8654_irq,
};

#ifdef CONFIG_OF
static const struct of_device_id sx8654_of_match[] = {
        {
                .compatible = "semtech,sx8650",
                .data = &sx8650_data,
        }, {
                .compatible = "semtech,sx8654",
                .data = &sx8654_data,
        }, {
                .compatible = "semtech,sx8655",
                .data = &sx8654_data,
        }, {
                .compatible = "semtech,sx8656",
                .data = &sx8654_data,
        },
        { }
};
MODULE_DEVICE_TABLE(of, sx8654_of_match);
#endif

static const struct i2c_device_id sx8654_id_table[] = {
        { .name = "semtech_sx8650", .driver_data = (long)&sx8650_data },
        { .name = "semtech_sx8654", .driver_data = (long)&sx8654_data },
        { .name = "semtech_sx8655", .driver_data = (long)&sx8654_data },
        { .name = "semtech_sx8656", .driver_data = (long)&sx8654_data },
        { }
};
MODULE_DEVICE_TABLE(i2c, sx8654_id_table);

static struct i2c_driver sx8654_driver = {
        .driver = {
                .name = "sx8654",
                .of_match_table = of_match_ptr(sx8654_of_match),
        },
        .id_table = sx8654_id_table,
        .probe = sx8654_probe,
};
module_i2c_driver(sx8654_driver);

MODULE_AUTHOR("Sébastien Szymanski <sebastien.szymanski@armadeus.com>");
MODULE_DESCRIPTION("Semtech SX8654 I2C Touchscreen Driver");
MODULE_LICENSE("GPL");