// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * TSI driver for Dialog DA9052
 *
 * Copyright(c) 2012 Dialog Semiconductor Ltd.
 *
 * Author: David Dajun Chen <dchen@diasemi.com>
 */
#include <linux/module.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>

#include <linux/mfd/da9052/reg.h>
#include <linux/mfd/da9052/da9052.h>

#define TSI_PEN_DOWN_STATUS 0x40

struct da9052_tsi {
        struct da9052 *da9052;
        struct input_dev *dev;
        struct delayed_work ts_pen_work;
        bool stopped;
        bool adc_on;
};

static void da9052_ts_adc_toggle(struct da9052_tsi *tsi, bool on)
{
        da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, 1 << 0, on);
        tsi->adc_on = on;
}

static irqreturn_t da9052_ts_pendwn_irq(int irq, void *data)
{
        struct da9052_tsi *tsi = data;

        if (!tsi->stopped) {
                /* Mask PEN_DOWN event and unmask TSI_READY event */
                da9052_disable_irq_nosync(tsi->da9052, DA9052_IRQ_PENDOWN);
                da9052_enable_irq(tsi->da9052, DA9052_IRQ_TSIREADY);

                da9052_ts_adc_toggle(tsi, true);

                schedule_delayed_work(&tsi->ts_pen_work, HZ / 50);
        }

        return IRQ_HANDLED;
}

static void da9052_ts_read(struct da9052_tsi *tsi)
{
        struct input_dev *input = tsi->dev;
        int ret;
        u16 x, y, z;
        u8 v;

        ret = da9052_reg_read(tsi->da9052, DA9052_TSI_X_MSB_REG);
        if (ret < 0)
                return;

        x = (u16) ret;

        ret = da9052_reg_read(tsi->da9052, DA9052_TSI_Y_MSB_REG);
        if (ret < 0)
                return;

        y = (u16) ret;

        ret = da9052_reg_read(tsi->da9052, DA9052_TSI_Z_MSB_REG);
        if (ret < 0)
                return;

        z = (u16) ret;

        ret = da9052_reg_read(tsi->da9052, DA9052_TSI_LSB_REG);
        if (ret < 0)
                return;

        v = (u8) ret;

        x = ((x << 2) & 0x3fc) | (v & 0x3);
        y = ((y << 2) & 0x3fc) | ((v & 0xc) >> 2);
        z = ((z << 2) & 0x3fc) | ((v & 0x30) >> 4);

        input_report_key(input, BTN_TOUCH, 1);
        input_report_abs(input, ABS_X, x);
        input_report_abs(input, ABS_Y, y);
        input_report_abs(input, ABS_PRESSURE, z);
        input_sync(input);
}

static irqreturn_t da9052_ts_datardy_irq(int irq, void *data)
{
        struct da9052_tsi *tsi = data;

        da9052_ts_read(tsi);

        return IRQ_HANDLED;
}

static void da9052_ts_pen_work(struct work_struct *work)
{
        struct da9052_tsi *tsi = container_of(work, struct da9052_tsi,
                                              ts_pen_work.work);
        if (!tsi->stopped) {
                int ret = da9052_reg_read(tsi->da9052, DA9052_TSI_LSB_REG);
                if (ret < 0 || (ret & TSI_PEN_DOWN_STATUS)) {
                        /* Pen is still DOWN (or read error) */
                        schedule_delayed_work(&tsi->ts_pen_work, HZ / 50);
                } else {
                        struct input_dev *input = tsi->dev;

                        /* Pen UP */
                        da9052_ts_adc_toggle(tsi, false);

                        /* Report Pen UP */
                        input_report_key(input, BTN_TOUCH, 0);
                        input_report_abs(input, ABS_PRESSURE, 0);
                        input_sync(input);

                        /*
                         * FIXME: Fixes the unhandled irq issue when quick
                         * pen down and pen up events occurs
                         */
                        ret = da9052_reg_update(tsi->da9052,
                                                DA9052_EVENT_B_REG, 0xC0, 0xC0);
                        if (ret < 0)
                                return;

                        /* Mask TSI_READY event and unmask PEN_DOWN event */
                        da9052_disable_irq(tsi->da9052, DA9052_IRQ_TSIREADY);
                        da9052_enable_irq(tsi->da9052, DA9052_IRQ_PENDOWN);
                }
        }
}

static int da9052_ts_configure_gpio(struct da9052 *da9052)
{
        int error;

        error = da9052_reg_update(da9052, DA9052_GPIO_2_3_REG, 0x30, 0);
        if (error < 0)
                return error;

        error = da9052_reg_update(da9052, DA9052_GPIO_4_5_REG, 0x33, 0);
        if (error < 0)
                return error;

        error = da9052_reg_update(da9052, DA9052_GPIO_6_7_REG, 0x33, 0);
        if (error < 0)
                return error;

        return 0;
}

static int da9052_configure_tsi(struct da9052_tsi *tsi)
{
        int error;

        error = da9052_ts_configure_gpio(tsi->da9052);
        if (error)
                return error;

        /* Measure TSI sample every 1ms */
        error = da9052_reg_update(tsi->da9052, DA9052_ADC_CONT_REG,
                                  1 << 6, 1 << 6);
        if (error < 0)
                return error;

        /* TSI_DELAY: 3 slots, TSI_SKIP: 0 slots, TSI_MODE: XYZP */
        error = da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, 0xFC, 0xC0);
        if (error < 0)
                return error;

        /* Supply TSIRef through LD09 */
        error = da9052_reg_write(tsi->da9052, DA9052_LDO9_REG, 0x59);
        if (error < 0)
                return error;

        return 0;
}

static int da9052_ts_input_open(struct input_dev *input_dev)
{
        struct da9052_tsi *tsi = input_get_drvdata(input_dev);

        tsi->stopped = false;
        mb();

        /* Unmask PEN_DOWN event */
        da9052_enable_irq(tsi->da9052, DA9052_IRQ_PENDOWN);

        /* Enable Pen Detect Circuit */
        return da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG,
                                 1 << 1, 1 << 1);
}

static void da9052_ts_input_close(struct input_dev *input_dev)
{
        struct da9052_tsi *tsi = input_get_drvdata(input_dev);

        tsi->stopped = true;
        mb();
        da9052_disable_irq(tsi->da9052, DA9052_IRQ_PENDOWN);
        cancel_delayed_work_sync(&tsi->ts_pen_work);

        if (tsi->adc_on) {
                da9052_disable_irq(tsi->da9052, DA9052_IRQ_TSIREADY);
                da9052_ts_adc_toggle(tsi, false);

                /*
                 * If ADC was on that means that pendwn IRQ was disabled
                 * twice and we need to enable it to keep enable/disable
                 * counter balanced. IRQ is still off though.
                 */
                da9052_enable_irq(tsi->da9052, DA9052_IRQ_PENDOWN);
        }

        /* Disable Pen Detect Circuit */
        da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, 1 << 1, 0);
}

static int da9052_ts_probe(struct platform_device *pdev)
{
        struct da9052 *da9052;
        struct da9052_tsi *tsi;
        struct input_dev *input_dev;
        int error;

        da9052 = dev_get_drvdata(pdev->dev.parent);
        if (!da9052)
                return -EINVAL;

        tsi = kzalloc_obj(*tsi);
        input_dev = input_allocate_device();
        if (!tsi || !input_dev) {
                error = -ENOMEM;
                goto err_free_mem;
        }

        tsi->da9052 = da9052;
        tsi->dev = input_dev;
        tsi->stopped = true;
        INIT_DELAYED_WORK(&tsi->ts_pen_work, da9052_ts_pen_work);

        input_dev->id.version = 0x0101;
        input_dev->id.vendor = 0x15B6;
        input_dev->id.product = 0x9052;
        input_dev->name = "Dialog DA9052 TouchScreen Driver";
        input_dev->dev.parent = &pdev->dev;
        input_dev->open = da9052_ts_input_open;
        input_dev->close = da9052_ts_input_close;

        __set_bit(EV_ABS, input_dev->evbit);
        __set_bit(EV_KEY, input_dev->evbit);
        __set_bit(BTN_TOUCH, input_dev->keybit);

        input_set_abs_params(input_dev, ABS_X, 0, 1023, 0, 0);
        input_set_abs_params(input_dev, ABS_Y, 0, 1023, 0, 0);
        input_set_abs_params(input_dev, ABS_PRESSURE, 0, 1023, 0, 0);

        input_set_drvdata(input_dev, tsi);

        /* Disable Pen Detect Circuit */
        da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, 1 << 1, 0);

        /* Disable ADC */
        da9052_ts_adc_toggle(tsi, false);

        error = da9052_request_irq(tsi->da9052, DA9052_IRQ_PENDOWN,
                                "pendown-irq", da9052_ts_pendwn_irq, tsi);
        if (error) {
                dev_err(tsi->da9052->dev,
                        "Failed to register PENDWN IRQ: %d\n", error);
                goto err_free_mem;
        }

        error = da9052_request_irq(tsi->da9052, DA9052_IRQ_TSIREADY,
                                "tsiready-irq", da9052_ts_datardy_irq, tsi);
        if (error) {
                dev_err(tsi->da9052->dev,
                        "Failed to register TSIRDY IRQ :%d\n", error);
                goto err_free_pendwn_irq;
        }

        /* Mask PEN_DOWN and TSI_READY events */
        da9052_disable_irq(tsi->da9052, DA9052_IRQ_PENDOWN);
        da9052_disable_irq(tsi->da9052, DA9052_IRQ_TSIREADY);

        error = da9052_configure_tsi(tsi);
        if (error)
                goto err_free_datardy_irq;

        error = input_register_device(tsi->dev);
        if (error)
                goto err_free_datardy_irq;

        platform_set_drvdata(pdev, tsi);

        return 0;

err_free_datardy_irq:
        da9052_free_irq(tsi->da9052, DA9052_IRQ_TSIREADY, tsi);
err_free_pendwn_irq:
        da9052_free_irq(tsi->da9052, DA9052_IRQ_PENDOWN, tsi);
err_free_mem:
        kfree(tsi);
        input_free_device(input_dev);

        return error;
}

static void da9052_ts_remove(struct platform_device *pdev)
{
        struct da9052_tsi *tsi = platform_get_drvdata(pdev);

        da9052_reg_write(tsi->da9052, DA9052_LDO9_REG, 0x19);

        da9052_free_irq(tsi->da9052, DA9052_IRQ_TSIREADY, tsi);
        da9052_free_irq(tsi->da9052, DA9052_IRQ_PENDOWN, tsi);

        input_unregister_device(tsi->dev);
        kfree(tsi);
}

static struct platform_driver da9052_tsi_driver = {
        .probe  = da9052_ts_probe,
        .remove = da9052_ts_remove,
        .driver = {
                .name   = "da9052-tsi",
        },
};

module_platform_driver(da9052_tsi_driver);

MODULE_DESCRIPTION("Touchscreen driver for Dialog Semiconductor DA9052");
MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9052-tsi");