// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Motorola PCAP2 touchscreen as found in the EZX phone platform.
 *
 *  Copyright (C) 2006 Harald Welte <laforge@openezx.org>
 *  Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/mfd/ezx-pcap.h>

struct pcap_ts {
        struct pcap_chip *pcap;
        struct input_dev *input;
        struct delayed_work work;
        u16 x, y;
        u16 pressure;
        u8 read_state;
};

#define SAMPLE_DELAY    20 /* msecs */

#define X_AXIS_MIN      0
#define X_AXIS_MAX      1023
#define Y_AXIS_MAX      X_AXIS_MAX
#define Y_AXIS_MIN      X_AXIS_MIN
#define PRESSURE_MAX    X_AXIS_MAX
#define PRESSURE_MIN    X_AXIS_MIN

static void pcap_ts_read_xy(void *data, u16 res[2])
{
        struct pcap_ts *pcap_ts = data;

        switch (pcap_ts->read_state) {
        case PCAP_ADC_TS_M_PRESSURE:
                /* pressure reading is unreliable */
                if (res[0] > PRESSURE_MIN && res[0] < PRESSURE_MAX)
                        pcap_ts->pressure = res[0];
                pcap_ts->read_state = PCAP_ADC_TS_M_XY;
                schedule_delayed_work(&pcap_ts->work, 0);
                break;
        case PCAP_ADC_TS_M_XY:
                pcap_ts->y = res[0];
                pcap_ts->x = res[1];
                if (pcap_ts->x <= X_AXIS_MIN || pcap_ts->x >= X_AXIS_MAX ||
                    pcap_ts->y <= Y_AXIS_MIN || pcap_ts->y >= Y_AXIS_MAX) {
                        /* pen has been released */
                        input_report_abs(pcap_ts->input, ABS_PRESSURE, 0);
                        input_report_key(pcap_ts->input, BTN_TOUCH, 0);

                        pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
                        schedule_delayed_work(&pcap_ts->work, 0);
                } else {
                        /* pen is touching the screen */
                        input_report_abs(pcap_ts->input, ABS_X, pcap_ts->x);
                        input_report_abs(pcap_ts->input, ABS_Y, pcap_ts->y);
                        input_report_key(pcap_ts->input, BTN_TOUCH, 1);
                        input_report_abs(pcap_ts->input, ABS_PRESSURE,
                                                pcap_ts->pressure);

                        /* switch back to pressure read mode */
                        pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
                        schedule_delayed_work(&pcap_ts->work,
                                        msecs_to_jiffies(SAMPLE_DELAY));
                }
                input_sync(pcap_ts->input);
                break;
        default:
                dev_warn(&pcap_ts->input->dev,
                                "pcap_ts: Warning, unhandled read_state %d\n",
                                pcap_ts->read_state);
                break;
        }
}

static void pcap_ts_work(struct work_struct *work)
{
        struct delayed_work *dw = to_delayed_work(work);
        struct pcap_ts *pcap_ts = container_of(dw, struct pcap_ts, work);
        u8 ch[2];

        pcap_set_ts_bits(pcap_ts->pcap,
                        pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);

        if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY)
                return;

        /* start adc conversion */
        ch[0] = PCAP_ADC_CH_TS_X1;
        ch[1] = PCAP_ADC_CH_TS_Y1;
        pcap_adc_async(pcap_ts->pcap, PCAP_ADC_BANK_1, 0, ch,
                                                pcap_ts_read_xy, pcap_ts);
}

static irqreturn_t pcap_ts_event_touch(int pirq, void *data)
{
        struct pcap_ts *pcap_ts = data;

        if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY) {
                pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
                schedule_delayed_work(&pcap_ts->work, 0);
        }
        return IRQ_HANDLED;
}

static int pcap_ts_open(struct input_dev *dev)
{
        struct pcap_ts *pcap_ts = input_get_drvdata(dev);

        pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
        schedule_delayed_work(&pcap_ts->work, 0);

        return 0;
}

static void pcap_ts_close(struct input_dev *dev)
{
        struct pcap_ts *pcap_ts = input_get_drvdata(dev);

        cancel_delayed_work_sync(&pcap_ts->work);

        pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
        pcap_set_ts_bits(pcap_ts->pcap,
                                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
}

static int pcap_ts_probe(struct platform_device *pdev)
{
        struct input_dev *input_dev;
        struct pcap_ts *pcap_ts;
        int err = -ENOMEM;

        pcap_ts = kzalloc_obj(*pcap_ts);
        if (!pcap_ts)
                return err;

        pcap_ts->pcap = dev_get_drvdata(pdev->dev.parent);
        platform_set_drvdata(pdev, pcap_ts);

        input_dev = input_allocate_device();
        if (!input_dev)
                goto fail;

        INIT_DELAYED_WORK(&pcap_ts->work, pcap_ts_work);

        pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
        pcap_set_ts_bits(pcap_ts->pcap,
                                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);

        pcap_ts->input = input_dev;
        input_set_drvdata(input_dev, pcap_ts);

        input_dev->name = "pcap-touchscreen";
        input_dev->phys = "pcap_ts/input0";
        input_dev->id.bustype = BUS_HOST;
        input_dev->id.vendor = 0x0001;
        input_dev->id.product = 0x0002;
        input_dev->id.version = 0x0100;
        input_dev->dev.parent = &pdev->dev;
        input_dev->open = pcap_ts_open;
        input_dev->close = pcap_ts_close;

        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
        input_set_abs_params(input_dev, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
        input_set_abs_params(input_dev, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
        input_set_abs_params(input_dev, ABS_PRESSURE, PRESSURE_MIN,
                             PRESSURE_MAX, 0, 0);

        err = input_register_device(pcap_ts->input);
        if (err)
                goto fail_allocate;

        err = request_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS),
                        pcap_ts_event_touch, 0, "Touch Screen", pcap_ts);
        if (err)
                goto fail_register;

        return 0;

fail_register:
        input_unregister_device(input_dev);
        goto fail;
fail_allocate:
        input_free_device(input_dev);
fail:
        kfree(pcap_ts);

        return err;
}

static void pcap_ts_remove(struct platform_device *pdev)
{
        struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);

        free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
        cancel_delayed_work_sync(&pcap_ts->work);

        input_unregister_device(pcap_ts->input);

        kfree(pcap_ts);
}

#ifdef CONFIG_PM
static int pcap_ts_suspend(struct device *dev)
{
        struct pcap_ts *pcap_ts = dev_get_drvdata(dev);

        pcap_set_ts_bits(pcap_ts->pcap, PCAP_ADC_TS_REF_LOWPWR);
        return 0;
}

static int pcap_ts_resume(struct device *dev)
{
        struct pcap_ts *pcap_ts = dev_get_drvdata(dev);

        pcap_set_ts_bits(pcap_ts->pcap,
                                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
        return 0;
}

static const struct dev_pm_ops pcap_ts_pm_ops = {
        .suspend        = pcap_ts_suspend,
        .resume         = pcap_ts_resume,
};
#define PCAP_TS_PM_OPS (&pcap_ts_pm_ops)
#else
#define PCAP_TS_PM_OPS NULL
#endif

static struct platform_driver pcap_ts_driver = {
        .probe          = pcap_ts_probe,
        .remove         = pcap_ts_remove,
        .driver         = {
                .name   = "pcap-ts",
                .pm     = PCAP_TS_PM_OPS,
        },
};
module_platform_driver(pcap_ts_driver);

MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pcap_ts");