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/*
* WHYCAN (哇酷®) Copyright (C)
*/

#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/thermal.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define TP_CTRL0        0x00
#define TP_CTRL1        0x04
#define TP_CTRL2        0x08
#define TP_CTRL3        0x0c
#define TP_INT_FIFOC        0x10
#define TP_INT_FIFOS        0x14
#define TP_TPR            0x18
#define TP_CDAT            0x1c
#define TEMP_DATA        0x20
#define TP_DATA            0x24

/* TP_CTRL0 bits */
#define ADC_FIRST_DLY(x)    ((x) << 24) /* 8 bits */
#define ADC_FIRST_DLY_MODE(x)    ((x) << 23)
#define ADC_CLK_SEL(x)        ((x) << 22)
#define ADC_CLK_DIV(x)        ((x) << 20) /* 3 bits */
#define FS_DIV(x)        ((x) << 16) /* 4 bits */
#define T_ACQ(x)        ((x) << 0) /* 16 bits */

/* TP_CTRL1 bits */
#define STYLUS_UP_DEBOUN(x)    ((x) << 12) /* 8 bits */
#define STYLUS_UP_DEBOUN_EN(x)    ((x) << 9)
#define TOUCH_PAN_CALI_EN(x)    ((x) << 6)
#define TP_DUAL_EN(x)        ((x) << 5)
#define TP_MODE_EN(x)        ((x) << 4)
#define TP_ADC_SELECT(x)    ((x) << 3)
#define ADC_CHAN_SELECT(x)    ((x) << 0)  /* 3 bits */

/* on sun6i, bits 3~6 are left shifted by 1 to 4~7 */
#define SUN6I_TP_MODE_EN(x)    ((x) << 5)

/* TP_CTRL2 bits */
#define TP_SENSITIVE_ADJUST(x)    ((x) << 28) /* 4 bits */
#define TP_MODE_SELECT(x)    ((x) << 26) /* 2 bits */
#define PRE_MEA_EN(x)        ((x) << 24)
#define PRE_MEA_THRE_CNT(x)    ((x) << 0) /* 24 bits */

/* TP_CTRL3 bits */
#define FILTER_EN(x)        ((x) << 2)
#define FILTER_TYPE(x)        ((x) << 0)  /* 2 bits */

/* TP_INT_FIFOC irq and fifo mask / control bits */
#define TEMP_IRQ_EN(x)        ((x) << 18)
#define OVERRUN_IRQ_EN(x)    ((x) << 17)
#define DATA_IRQ_EN(x)        ((x) << 16)
#define TP_DATA_XY_CHANGE(x)    ((x) << 13)
#define FIFO_TRIG(x)        ((x) << 8)  /* 5 bits */
#define DATA_DRQ_EN(x)        ((x) << 7)
#define FIFO_FLUSH(x)        ((x) << 4)
#define TP_UP_IRQ_EN(x)        ((x) << 1)
#define TP_DOWN_IRQ_EN(x)    ((x) << 0)

/* TP_INT_FIFOS irq and fifo status bits */
#define TEMP_DATA_PENDING    BIT(18)
#define FIFO_OVERRUN_PENDING    BIT(17)
#define FIFO_DATA_PENDING    BIT(16)
#define TP_IDLE_FLG        BIT(2)
#define TP_UP_PENDING        BIT(1)
#define TP_DOWN_PENDING        BIT(0)

/* TP_TPR bits */
#define TEMP_ENABLE(x)        ((x) << 16)
#define TEMP_PERIOD(x)        ((x) << 0)  /* t = x * 256 * 16 / clkin */

struct sun4i_ts_data {
    struct device *dev;
    struct input_dev *input;
    void __iomem *base;
    unsigned int irq;
    bool ignore_fifo_data;
    int temp_data;
    int temp_offset;
    int temp_step;
};

static void sun4i_ts_irq_handle_input(struct sun4i_ts_data *ts, u32 reg_val)
{
    u32 x, y;

    if (reg_val & FIFO_DATA_PENDING) {
        x = readl(ts->base + TP_DATA);
        y = readl(ts->base + TP_DATA);
        /* The 1st location reported after an up event is unreliable */
        if (!ts->ignore_fifo_data) {
            input_report_abs(ts->input, ABS_X, x);
            input_report_abs(ts->input, ABS_Y, y);
            /*
             * The hardware has a separate down status bit, but
             * that gets set before we get the first location,
             * resulting in reporting a click on the old location.
             */
            input_report_key(ts->input, BTN_TOUCH, 1);
            input_sync(ts->input);
        } else {
            ts->ignore_fifo_data = false;
        }
    }

    if (reg_val & TP_UP_PENDING) {
        ts->ignore_fifo_data = true;
        input_report_key(ts->input, BTN_TOUCH, 0);
        input_sync(ts->input);
    }
}

static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
{
    struct sun4i_ts_data *ts = dev_id;
    u32 reg_val;

    reg_val  = readl(ts->base + TP_INT_FIFOS);

    if (reg_val & TEMP_DATA_PENDING)
        ts->temp_data = readl(ts->base + TEMP_DATA);

    if (ts->input)
        sun4i_ts_irq_handle_input(ts, reg_val);

    writel(reg_val, ts->base + TP_INT_FIFOS);

    return IRQ_HANDLED;
}

static int sun4i_ts_open(struct input_dev *dev)
{
    struct sun4i_ts_data *ts = input_get_drvdata(dev);

    /* Flush, set trig level to 1, enable temp, data and up irqs */
    writel(TEMP_IRQ_EN(1) | DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) |
        TP_UP_IRQ_EN(1), ts->base + TP_INT_FIFOC);

    return 0;
}

static void sun4i_ts_close(struct input_dev *dev)
{
    struct sun4i_ts_data *ts = input_get_drvdata(dev);

    /* Deactivate all input IRQs */
    writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
}

static int sun4i_get_temp(const struct sun4i_ts_data *ts, int *temp)
{
    /* No temp_data until the first irq */
    if (ts->temp_data == -1)
        return -EAGAIN;

    *temp = ts->temp_data * ts->temp_step - ts->temp_offset;

    return 0;
}

static int sun4i_get_tz_temp(void *data, int *temp)
{
    return sun4i_get_temp(data, temp);
}

static const struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
    .get_temp = sun4i_get_tz_temp,
};

static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
             char *buf)
{
    struct sun4i_ts_data *ts = dev_get_drvdata(dev);
    int temp;
    int error;

    error = sun4i_get_temp(ts, &temp);
    if (error)
        return error;

    return sprintf(buf, "%d\n", temp);
}

static ssize_t show_temp_label(struct device *dev,
                  struct device_attribute *devattr, char *buf)
{
    return sprintf(buf, "SoC temperature\n");
}

static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);

static struct attribute *sun4i_ts_attrs[] = {
    &dev_attr_temp1_input.attr,
    &dev_attr_temp1_label.attr,
    NULL
};
ATTRIBUTE_GROUPS(sun4i_ts);

static int sun4i_ts_probe(struct platform_device *pdev)
{
    struct sun4i_ts_data *ts;
    struct device *dev = &pdev->dev;
    struct device_node *np = dev->of_node;
    struct device *hwmon;
    int error;
    u32 reg;
    bool ts_attached;
    u32 tp_sensitive_adjust = 15;
    u32 filter_type = 1;

    ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
    if (!ts)
        return -ENOMEM;

    ts->dev = dev;
    ts->ignore_fifo_data = true;
    ts->temp_data = -1;
    if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts")) {
        /* Allwinner SDK has temperature (C) = (value / 6) - 271 */
        ts->temp_offset = 271000;
        ts->temp_step = 167;
    } else if (of_device_is_compatible(np, "allwinner,sun4i-a10-ts")) {
        /*
         * The A10 temperature sensor has quite a wide spread, these
         * parameters are based on the averaging of the calibration
         * results of 4 completely different boards, with a spread of
         * temp_step from 0.096 - 0.170 and temp_offset from 176 - 331.
         */
        ts->temp_offset = 257000;
        ts->temp_step = 133;
    } else {
        /*
         * The user manuals do not contain the formula for calculating
         * the temperature. The formula used here is from the AXP209,
         * which is designed by X-Powers, an affiliate of Allwinner:
         *
         *     temperature (C) = (value * 0.1) - 144.7
         *
         * Allwinner does not have any documentation whatsoever for
         * this hardware. Moreover, it is claimed that the sensor
         * is inaccurate and cannot work properly.
         */
        ts->temp_offset = 144700;
        ts->temp_step = 100;
    }

    ts_attached = of_property_read_bool(np, "allwinner,ts-attached");
    if (ts_attached) {
        ts->input = devm_input_allocate_device(dev);
        if (!ts->input)
            return -ENOMEM;

        ts->input->name = pdev->name;
        ts->input->phys = "sun4i_ts/input0";
        ts->input->open = sun4i_ts_open;
        ts->input->close = sun4i_ts_close;
        ts->input->id.bustype = BUS_HOST;
        ts->input->id.vendor = 0x0001;
        ts->input->id.product = 0x0001;
        ts->input->id.version = 0x0100;
        ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
        __set_bit(BTN_TOUCH, ts->input->keybit);
        input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
        input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
        input_set_drvdata(ts->input, ts);
    }

    ts->base = devm_ioremap_resource(dev,
                  platform_get_resource(pdev, IORESOURCE_MEM, 0));
    if (IS_ERR(ts->base))
        return PTR_ERR(ts->base);

    ts->irq = platform_get_irq(pdev, 0);
    error = devm_request_irq(dev, ts->irq, sun4i_ts_irq, 0, "sun4i-ts", ts);
    if (error)
        return error;

    /*
     * Select HOSC clk, clkin = clk / 6, adc samplefreq = clkin / 8192,
     * t_acq = clkin / (16 * 64)
     */
    writel(ADC_CLK_SEL(0) | ADC_CLK_DIV(2) | FS_DIV(7) | T_ACQ(63),
           ts->base + TP_CTRL0);

    /*
     * tp_sensitive_adjust is an optional property
     * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
     */
    of_property_read_u32(np, "allwinner,tp-sensitive-adjust",
                 &tp_sensitive_adjust);
    writel(TP_SENSITIVE_ADJUST(tp_sensitive_adjust) | TP_MODE_SELECT(0),
           ts->base + TP_CTRL2);

    /*
     * Enable median and averaging filter, optional property for
     * filter type.
     */
    of_property_read_u32(np, "allwinner,filter-type", &filter_type);
    writel(FILTER_EN(1) | FILTER_TYPE(filter_type), ts->base + TP_CTRL3);

    /* Enable temperature measurement, period 1953 (2 seconds) */
    writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);

    /*
     * Set stylus up debounce to aprox 10 ms, enable debounce, and
     * finally enable tp mode.
     */
    reg = STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1);
    if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts"))
        reg |= SUN6I_TP_MODE_EN(1);
    else
        reg |= TP_MODE_EN(1);
    writel(reg, ts->base + TP_CTRL1);

    /*
     * The thermal core does not register hwmon devices for DT-based
     * thermal zone sensors, such as this one.
     */
    hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts",
                               ts, sun4i_ts_groups);
    if (IS_ERR(hwmon))
        return PTR_ERR(hwmon);

    devm_thermal_zone_of_sensor_register(ts->dev, 0, ts, &sun4i_ts_tz_ops);

    writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);

    if (ts_attached) {
        error = input_register_device(ts->input);
        if (error) {
            writel(0, ts->base + TP_INT_FIFOC);
            return error;
        }
    }

    platform_set_drvdata(pdev, ts);
    return 0;
}

static int sun4i_ts_remove(struct platform_device *pdev)
{
    struct sun4i_ts_data *ts = platform_get_drvdata(pdev);

    /* Explicit unregister to avoid open/close changing the imask later */
    if (ts->input)
        input_unregister_device(ts->input);

    /* Deactivate all IRQs */
    writel(0, ts->base + TP_INT_FIFOC);

    return 0;
}

static const struct of_device_id sun4i_ts_of_match[] = {
    { .compatible = "allwinner,sun4i-a10-ts", },
    { .compatible = "allwinner,sun5i-a13-ts", },
    { .compatible = "allwinner,sun6i-a31-ts", },
    { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);

static struct platform_driver sun4i_ts_driver = {
    .driver = {
        .name    = "sun4i-ts",
        .of_match_table = of_match_ptr(sun4i_ts_of_match),
    },
    .probe    = sun4i_ts_probe,
    .remove    = sun4i_ts_remove,
};

module_platform_driver(sun4i_ts_driver);

MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");