// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * STMicroelectronics STMPE811 Touchscreen Driver
 *
 * (C) 2010 Luotao Fu <l.fu@pengutronix.de>
 * All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/input/touchscreen.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/workqueue.h>

#include <linux/mfd/stmpe.h>

/* Register layouts and functionalities are identical on all stmpexxx variants
 * with touchscreen controller
 */
#define STMPE_REG_INT_STA               0x0B
#define STMPE_REG_TSC_CTRL              0x40
#define STMPE_REG_TSC_CFG               0x41
#define STMPE_REG_FIFO_TH               0x4A
#define STMPE_REG_FIFO_STA              0x4B
#define STMPE_REG_FIFO_SIZE             0x4C
#define STMPE_REG_TSC_DATA_XYZ          0x52
#define STMPE_REG_TSC_FRACTION_Z        0x56
#define STMPE_REG_TSC_I_DRIVE           0x58

#define OP_MOD_XYZ                      0

#define STMPE_TSC_CTRL_TSC_EN           (1<<0)

#define STMPE_FIFO_STA_RESET            (1<<0)

#define STMPE_IRQ_TOUCH_DET             0

#define STMPE_TS_NAME                   "stmpe-ts"
#define XY_MASK                         0xfff

/**
 * struct stmpe_touch - stmpe811 touch screen controller state
 * @stmpe: pointer back to STMPE MFD container
 * @idev: registered input device
 * @work: a work item used to scan the device
 * @dev: a pointer back to the MFD cell struct device*
 * @prop: Touchscreen properties
 * @ave_ctrl: Sample average control
 * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
 * @touch_det_delay: Touch detect interrupt delay
 * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
 * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
 * recommended is 3
 * @settling: Panel driver settling time
 * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
 * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
 * recommended is 2
 * @fraction_z: Length of the fractional part in z
 * (fraction_z ([0..7]) = Count of the fractional part)
 * recommended is 7
 * @i_drive: current limit value of the touchscreen drivers
 * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
 */
struct stmpe_touch {
        struct stmpe *stmpe;
        struct input_dev *idev;
        struct delayed_work work;
        struct device *dev;
        struct touchscreen_properties prop;
        u8 ave_ctrl;
        u8 touch_det_delay;
        u8 settling;
        u8 fraction_z;
        u8 i_drive;
};

static int __stmpe_reset_fifo(struct stmpe *stmpe)
{
        int ret;

        ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
                        STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
        if (ret)
                return ret;

        return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
                        STMPE_FIFO_STA_RESET, 0);
}

static void stmpe_work(struct work_struct *work)
{
        int int_sta;
        u32 timeout = 40;

        struct stmpe_touch *ts =
            container_of(work, struct stmpe_touch, work.work);

        int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);

        /*
         * touch_det sometimes get desasserted or just get stuck. This appears
         * to be a silicon bug, We still have to clarify this with the
         * manufacture. As a workaround We release the key anyway if the
         * touch_det keeps coming in after 4ms, while the FIFO contains no value
         * during the whole time.
         */
        while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
                timeout--;
                int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
                udelay(100);
        }

        /* reset the FIFO before we report release event */
        __stmpe_reset_fifo(ts->stmpe);

        input_report_abs(ts->idev, ABS_PRESSURE, 0);
        input_report_key(ts->idev, BTN_TOUCH, 0);
        input_sync(ts->idev);
}

static irqreturn_t stmpe_ts_handler(int irq, void *data)
{
        u8 data_set[4];
        int x, y, z;
        struct stmpe_touch *ts = data;

        /*
         * Cancel scheduled polling for release if we have new value
         * available. Wait if the polling is already running.
         */
        cancel_delayed_work_sync(&ts->work);

        /*
         * The FIFO sometimes just crashes and stops generating interrupts. This
         * appears to be a silicon bug. We still have to clarify this with
         * the manufacture. As a workaround we disable the TSC while we are
         * collecting data and flush the FIFO after reading
         */
        stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
                                STMPE_TSC_CTRL_TSC_EN, 0);

        stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);

        x = (data_set[0] << 4) | (data_set[1] >> 4);
        y = ((data_set[1] & 0xf) << 8) | data_set[2];
        z = data_set[3];

        touchscreen_report_pos(ts->idev, &ts->prop, x, y, false);
        input_report_abs(ts->idev, ABS_PRESSURE, z);
        input_report_key(ts->idev, BTN_TOUCH, 1);
        input_sync(ts->idev);

       /* flush the FIFO after we have read out our values. */
        __stmpe_reset_fifo(ts->stmpe);

        /* reenable the tsc */
        stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
                        STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);

        /* start polling for touch_det to detect release */
        schedule_delayed_work(&ts->work, msecs_to_jiffies(50));

        return IRQ_HANDLED;
}

static int stmpe_init_hw(struct stmpe_touch *ts)
{
        int ret;
        u8 tsc_cfg, tsc_cfg_mask;
        struct stmpe *stmpe = ts->stmpe;
        struct device *dev = ts->dev;

        ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
        if (ret) {
                dev_err(dev, "Could not enable clock for ADC and TS\n");
                return ret;
        }

        ret = stmpe811_adc_common_init(stmpe);
        if (ret) {
                stmpe_disable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
                return ret;
        }

        tsc_cfg = STMPE_AVE_CTRL(ts->ave_ctrl) |
                  STMPE_DET_DELAY(ts->touch_det_delay) |
                  STMPE_SETTLING(ts->settling);
        tsc_cfg_mask = STMPE_AVE_CTRL(0xff) | STMPE_DET_DELAY(0xff) |
                       STMPE_SETTLING(0xff);

        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
        if (ret) {
                dev_err(dev, "Could not config touch\n");
                return ret;
        }

        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
                        STMPE_FRACTION_Z(0xff), STMPE_FRACTION_Z(ts->fraction_z));
        if (ret) {
                dev_err(dev, "Could not config touch\n");
                return ret;
        }

        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
                        STMPE_I_DRIVE(0xff), STMPE_I_DRIVE(ts->i_drive));
        if (ret) {
                dev_err(dev, "Could not config touch\n");
                return ret;
        }

        /* set FIFO to 1 for single point reading */
        ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
        if (ret) {
                dev_err(dev, "Could not set FIFO\n");
                return ret;
        }

        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
                        STMPE_OP_MODE(0xff), STMPE_OP_MODE(OP_MOD_XYZ));
        if (ret) {
                dev_err(dev, "Could not set mode\n");
                return ret;
        }

        return 0;
}

static int stmpe_ts_open(struct input_dev *dev)
{
        struct stmpe_touch *ts = input_get_drvdata(dev);
        int ret = 0;

        ret = __stmpe_reset_fifo(ts->stmpe);
        if (ret)
                return ret;

        return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
                        STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
}

static void stmpe_ts_close(struct input_dev *dev)
{
        struct stmpe_touch *ts = input_get_drvdata(dev);

        cancel_delayed_work_sync(&ts->work);

        stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
                        STMPE_TSC_CTRL_TSC_EN, 0);
}

static void stmpe_ts_get_platform_info(struct platform_device *pdev,
                                        struct stmpe_touch *ts)
{
        struct device_node *np = pdev->dev.of_node;
        u32 val;

        if (np) {
                if (!of_property_read_u32(np, "st,sample-time", &val))
                        ts->stmpe->sample_time = val;
                if (!of_property_read_u32(np, "st,mod-12b", &val))
                        ts->stmpe->mod_12b = val;
                if (!of_property_read_u32(np, "st,ref-sel", &val))
                        ts->stmpe->ref_sel = val;
                if (!of_property_read_u32(np, "st,adc-freq", &val))
                        ts->stmpe->adc_freq = val;
                if (!of_property_read_u32(np, "st,ave-ctrl", &val))
                        ts->ave_ctrl = val;
                if (!of_property_read_u32(np, "st,touch-det-delay", &val))
                        ts->touch_det_delay = val;
                if (!of_property_read_u32(np, "st,settling", &val))
                        ts->settling = val;
                if (!of_property_read_u32(np, "st,fraction-z", &val))
                        ts->fraction_z = val;
                if (!of_property_read_u32(np, "st,i-drive", &val))
                        ts->i_drive = val;
        }
}

static int stmpe_input_probe(struct platform_device *pdev)
{
        struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
        struct stmpe_touch *ts;
        struct input_dev *idev;
        int error;
        int ts_irq;

        ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
        if (ts_irq < 0)
                return ts_irq;

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

        idev = devm_input_allocate_device(&pdev->dev);
        if (!idev)
                return -ENOMEM;

        platform_set_drvdata(pdev, ts);
        ts->stmpe = stmpe;
        ts->idev = idev;
        ts->dev = &pdev->dev;

        stmpe_ts_get_platform_info(pdev, ts);

        INIT_DELAYED_WORK(&ts->work, stmpe_work);

        error = devm_request_threaded_irq(&pdev->dev, ts_irq,
                                          NULL, stmpe_ts_handler,
                                          IRQF_ONESHOT, STMPE_TS_NAME, ts);
        if (error) {
                dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
                return error;
        }

        error = stmpe_init_hw(ts);
        if (error)
                return error;

        idev->name = STMPE_TS_NAME;
        idev->phys = STMPE_TS_NAME"/input0";
        idev->id.bustype = BUS_I2C;

        idev->open = stmpe_ts_open;
        idev->close = stmpe_ts_close;

        input_set_drvdata(idev, ts);

        input_set_capability(idev, EV_KEY, BTN_TOUCH);
        input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
        input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
        input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);

        touchscreen_parse_properties(idev, false, &ts->prop);

        error = input_register_device(idev);
        if (error) {
                dev_err(&pdev->dev, "Could not register input device\n");
                return error;
        }

        return 0;
}

static void stmpe_ts_remove(struct platform_device *pdev)
{
        struct stmpe_touch *ts = platform_get_drvdata(pdev);

        stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
}

static struct platform_driver stmpe_ts_driver = {
        .driver = {
                .name = STMPE_TS_NAME,
        },
        .probe = stmpe_input_probe,
        .remove = stmpe_ts_remove,
};
module_platform_driver(stmpe_ts_driver);

MODULE_ALIAS("platform:stmpe-ts");
MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
MODULE_LICENSE("GPL");