root/drivers/input/joystick/analog.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) 1996-2001 Vojtech Pavlik
 */

/*
 * Analog joystick and gamepad driver for Linux
 */

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/gameport.h>
#include <linux/jiffies.h>
#include <linux/seq_buf.h>
#include <linux/timex.h>
#include <linux/timekeeping.h>

#define DRIVER_DESC     "Analog joystick and gamepad driver"

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Option parsing.
 */

#define ANALOG_PORTS            16

static char *js[ANALOG_PORTS];
static unsigned int js_nargs;
static int analog_options[ANALOG_PORTS];
module_param_array_named(map, js, charp, &js_nargs, 0);
MODULE_PARM_DESC(map, "Describes analog joysticks type/capabilities");

/*
 * Times, feature definitions.
 */

#define ANALOG_RUDDER           0x00004
#define ANALOG_THROTTLE         0x00008
#define ANALOG_AXES_STD         0x0000f
#define ANALOG_BTNS_STD         0x000f0

#define ANALOG_BTNS_CHF         0x00100
#define ANALOG_HAT1_CHF         0x00200
#define ANALOG_HAT2_CHF         0x00400
#define ANALOG_HAT_FCS          0x00800
#define ANALOG_HATS_ALL         0x00e00
#define ANALOG_BTN_TL           0x01000
#define ANALOG_BTN_TR           0x02000
#define ANALOG_BTN_TL2          0x04000
#define ANALOG_BTN_TR2          0x08000
#define ANALOG_BTNS_TLR         0x03000
#define ANALOG_BTNS_TLR2        0x0c000
#define ANALOG_BTNS_GAMEPAD     0x0f000

#define ANALOG_HBTN_CHF         0x10000
#define ANALOG_ANY_CHF          0x10700
#define ANALOG_SAITEK           0x20000
#define ANALOG_EXTENSIONS       0x7ff00
#define ANALOG_GAMEPAD          0x80000

#define ANALOG_MAX_TIME         3       /* 3 ms */
#define ANALOG_LOOP_TIME        2000    /* 2 * loop */
#define ANALOG_SAITEK_DELAY     200     /* 200 us */
#define ANALOG_SAITEK_TIME      2000    /* 2000 us */
#define ANALOG_AXIS_TIME        2       /* 2 * refresh */
#define ANALOG_INIT_RETRIES     8       /* 8 times */
#define ANALOG_FUZZ_BITS        2       /* 2 bit more */
#define ANALOG_FUZZ_MAGIC       36      /* 36 u*ms/loop */

#define ANALOG_MAX_NAME_LENGTH  128
#define ANALOG_MAX_PHYS_LENGTH  32

static short analog_axes[] = { ABS_X, ABS_Y, ABS_RUDDER, ABS_THROTTLE };
static short analog_hats[] = { ABS_HAT0X, ABS_HAT0Y, ABS_HAT1X, ABS_HAT1Y, ABS_HAT2X, ABS_HAT2Y };
static short analog_pads[] = { BTN_Y, BTN_Z, BTN_TL, BTN_TR };
static short analog_exts[] = { ANALOG_HAT1_CHF, ANALOG_HAT2_CHF, ANALOG_HAT_FCS };
static short analog_pad_btn[] = { BTN_A, BTN_B, BTN_C, BTN_X, BTN_TL2, BTN_TR2, BTN_SELECT, BTN_START, BTN_MODE, BTN_BASE };
static short analog_joy_btn[] = { BTN_TRIGGER, BTN_THUMB, BTN_TOP, BTN_TOP2, BTN_BASE, BTN_BASE2,
                                  BTN_BASE3, BTN_BASE4, BTN_BASE5, BTN_BASE6 };

static unsigned char analog_chf[] = { 0xf, 0x0, 0x1, 0x9, 0x2, 0x4, 0xc, 0x8, 0x3, 0x5, 0xb, 0x7, 0xd, 0xe, 0xa, 0x6 };

struct analog {
        struct input_dev *dev;
        int mask;
        short *buttons;
        char name[ANALOG_MAX_NAME_LENGTH];
        char phys[ANALOG_MAX_PHYS_LENGTH];
};

struct analog_port {
        struct gameport *gameport;
        struct analog analog[2];
        unsigned char mask;
        char saitek;
        char cooked;
        int bads;
        int reads;
        int loop;
        int fuzz;
        int axes[4];
        int buttons;
        int initial[4];
        int axtime;
};

/*
 * analog_decode() decodes analog joystick data and reports input events.
 */

static void analog_decode(struct analog *analog, int *axes, int *initial, int buttons)
{
        struct input_dev *dev = analog->dev;
        int i, j;

        if (analog->mask & ANALOG_HAT_FCS)
                for (i = 0; i < 4; i++)
                        if (axes[3] < ((initial[3] * ((i << 1) + 1)) >> 3)) {
                                buttons |= 1 << (i + 14);
                                break;
                        }

        for (i = j = 0; i < 6; i++)
                if (analog->mask & (0x10 << i))
                        input_report_key(dev, analog->buttons[j++], (buttons >> i) & 1);

        if (analog->mask & ANALOG_HBTN_CHF)
                for (i = 0; i < 4; i++)
                        input_report_key(dev, analog->buttons[j++], (buttons >> (i + 10)) & 1);

        if (analog->mask & ANALOG_BTN_TL)
                input_report_key(dev, analog_pads[0], axes[2] < (initial[2] >> 1));
        if (analog->mask & ANALOG_BTN_TR)
                input_report_key(dev, analog_pads[1], axes[3] < (initial[3] >> 1));
        if (analog->mask & ANALOG_BTN_TL2)
                input_report_key(dev, analog_pads[2], axes[2] > (initial[2] + (initial[2] >> 1)));
        if (analog->mask & ANALOG_BTN_TR2)
                input_report_key(dev, analog_pads[3], axes[3] > (initial[3] + (initial[3] >> 1)));

        for (i = j = 0; i < 4; i++)
                if (analog->mask & (1 << i))
                        input_report_abs(dev, analog_axes[j++], axes[i]);

        for (i = j = 0; i < 3; i++)
                if (analog->mask & analog_exts[i]) {
                        input_report_abs(dev, analog_hats[j++],
                                ((buttons >> ((i << 2) + 7)) & 1) - ((buttons >> ((i << 2) + 9)) & 1));
                        input_report_abs(dev, analog_hats[j++],
                                ((buttons >> ((i << 2) + 8)) & 1) - ((buttons >> ((i << 2) + 6)) & 1));
                }

        input_sync(dev);
}

/*
 * analog_cooked_read() reads analog joystick data.
 */

static int analog_cooked_read(struct analog_port *port)
{
        struct gameport *gameport = port->gameport;
        ktime_t time[4], start, loop, now;
        unsigned int loopout, timeout;
        unsigned char data[4], this, last;
        unsigned long flags;
        int i, j;

        loopout = (ANALOG_LOOP_TIME * port->loop) / 1000;
        timeout = ANALOG_MAX_TIME * NSEC_PER_MSEC;

        local_irq_save(flags);
        gameport_trigger(gameport);
        now = ktime_get();
        local_irq_restore(flags);

        start = now;
        this = port->mask;
        i = 0;

        do {
                loop = now;
                last = this;

                local_irq_disable();
                this = gameport_read(gameport) & port->mask;
                now = ktime_get();
                local_irq_restore(flags);

                if ((last ^ this) && (ktime_sub(now, loop) < loopout)) {
                        data[i] = last ^ this;
                        time[i] = now;
                        i++;
                }

        } while (this && (i < 4) && (ktime_sub(now, start) < timeout));

        this <<= 4;

        for (--i; i >= 0; i--) {
                this |= data[i];
                for (j = 0; j < 4; j++)
                        if (data[i] & (1 << j))
                                port->axes[j] = ((u32)ktime_sub(time[i], start) << ANALOG_FUZZ_BITS) / port->loop;
        }

        return -(this != port->mask);
}

static int analog_button_read(struct analog_port *port, char saitek, char chf)
{
        unsigned char u;
        int t = 1, i = 0;
        int strobe = gameport_time(port->gameport, ANALOG_SAITEK_TIME);

        u = gameport_read(port->gameport);

        if (!chf) {
                port->buttons = (~u >> 4) & 0xf;
                return 0;
        }

        port->buttons = 0;

        while ((~u & 0xf0) && (i < 16) && t) {
                port->buttons |= 1 << analog_chf[(~u >> 4) & 0xf];
                if (!saitek) return 0;
                udelay(ANALOG_SAITEK_DELAY);
                t = strobe;
                gameport_trigger(port->gameport);
                while (((u = gameport_read(port->gameport)) & port->mask) && t) t--;
                i++;
        }

        return -(!t || (i == 16));
}

/*
 * analog_poll() repeatedly polls the Analog joysticks.
 */

static void analog_poll(struct gameport *gameport)
{
        struct analog_port *port = gameport_get_drvdata(gameport);
        int i;

        char saitek = !!(port->analog[0].mask & ANALOG_SAITEK);
        char chf = !!(port->analog[0].mask & ANALOG_ANY_CHF);

        if (port->cooked) {
                port->bads -= gameport_cooked_read(port->gameport, port->axes, &port->buttons);
                if (chf)
                        port->buttons = port->buttons ? (1 << analog_chf[port->buttons]) : 0;
                port->reads++;
        } else {
                if (!port->axtime--) {
                        port->bads -= analog_cooked_read(port);
                        port->bads -= analog_button_read(port, saitek, chf);
                        port->reads++;
                        port->axtime = ANALOG_AXIS_TIME - 1;
                } else {
                        if (!saitek)
                                analog_button_read(port, saitek, chf);
                }
        }

        for (i = 0; i < 2; i++)
                if (port->analog[i].mask)
                        analog_decode(port->analog + i, port->axes, port->initial, port->buttons);
}

/*
 * analog_open() is a callback from the input open routine.
 */

static int analog_open(struct input_dev *dev)
{
        struct analog_port *port = input_get_drvdata(dev);

        gameport_start_polling(port->gameport);
        return 0;
}

/*
 * analog_close() is a callback from the input close routine.
 */

static void analog_close(struct input_dev *dev)
{
        struct analog_port *port = input_get_drvdata(dev);

        gameport_stop_polling(port->gameport);
}

/*
 * analog_calibrate_timer() calibrates the timer and computes loop
 * and timeout values for a joystick port.
 */

static void analog_calibrate_timer(struct analog_port *port)
{
        struct gameport *gameport = port->gameport;
        unsigned int i, t, tx;
        ktime_t t1, t2, t3;
        unsigned long flags;

        tx = ~0;

        for (i = 0; i < 50; i++) {
                local_irq_save(flags);
                t1 = ktime_get();
                for (t = 0; t < 50; t++) {
                        gameport_read(gameport);
                        t2 = ktime_get();
                }
                t3 = ktime_get();
                local_irq_restore(flags);
                udelay(i);
                t = ktime_sub(t2, t1) - ktime_sub(t3, t2);
                if (t < tx) tx = t;
        }

        port->loop = tx / 50;
}

/*
 * analog_name() constructs a name for an analog joystick.
 */

static void analog_name(struct analog *analog)
{
        struct seq_buf s;

        seq_buf_init(&s, analog->name, sizeof(analog->name));
        seq_buf_printf(&s, "Analog %d-axis %d-button",
                 hweight8(analog->mask & ANALOG_AXES_STD),
                 hweight8(analog->mask & ANALOG_BTNS_STD) + !!(analog->mask & ANALOG_BTNS_CHF) * 2 +
                 hweight16(analog->mask & ANALOG_BTNS_GAMEPAD) + !!(analog->mask & ANALOG_HBTN_CHF) * 4);

        if (analog->mask & ANALOG_HATS_ALL)
                seq_buf_printf(&s, " %d-hat",
                               hweight16(analog->mask & ANALOG_HATS_ALL));

        if (analog->mask & ANALOG_HAT_FCS)
                seq_buf_printf(&s, " FCS");
        if (analog->mask & ANALOG_ANY_CHF)
                seq_buf_printf(&s, (analog->mask & ANALOG_SAITEK) ? " Saitek" : " CHF");

        seq_buf_printf(&s, (analog->mask & ANALOG_GAMEPAD) ? " gamepad" : " joystick");
}

/*
 * analog_init_device()
 */

static int analog_init_device(struct analog_port *port, struct analog *analog, int index)
{
        struct input_dev *input_dev;
        int i, j, t, v, w, x, y, z;
        int error;

        analog_name(analog);
        snprintf(analog->phys, sizeof(analog->phys),
                 "%s/input%d", port->gameport->phys, index);
        analog->buttons = (analog->mask & ANALOG_GAMEPAD) ? analog_pad_btn : analog_joy_btn;

        analog->dev = input_dev = input_allocate_device();
        if (!input_dev)
                return -ENOMEM;

        input_dev->name = analog->name;
        input_dev->phys = analog->phys;
        input_dev->id.bustype = BUS_GAMEPORT;
        input_dev->id.vendor = GAMEPORT_ID_VENDOR_ANALOG;
        input_dev->id.product = analog->mask >> 4;
        input_dev->id.version = 0x0100;
        input_dev->dev.parent = &port->gameport->dev;

        input_set_drvdata(input_dev, port);

        input_dev->open = analog_open;
        input_dev->close = analog_close;

        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

        for (i = j = 0; i < 4; i++)
                if (analog->mask & (1 << i)) {

                        t = analog_axes[j];
                        x = port->axes[i];
                        y = (port->axes[0] + port->axes[1]) >> 1;
                        z = y - port->axes[i];
                        z = z > 0 ? z : -z;
                        v = (x >> 3);
                        w = (x >> 3);

                        if ((i == 2 || i == 3) && (j == 2 || j == 3) && (z > (y >> 3)))
                                x = y;

                        if (analog->mask & ANALOG_SAITEK) {
                                if (i == 2) x = port->axes[i];
                                v = x - (x >> 2);
                                w = (x >> 4);
                        }

                        input_set_abs_params(input_dev, t, v, (x << 1) - v, port->fuzz, w);
                        j++;
                }

        for (i = j = 0; i < 3; i++)
                if (analog->mask & analog_exts[i])
                        for (x = 0; x < 2; x++) {
                                t = analog_hats[j++];
                                input_set_abs_params(input_dev, t, -1, 1, 0, 0);
                        }

        for (i = j = 0; i < 4; i++)
                if (analog->mask & (0x10 << i))
                        set_bit(analog->buttons[j++], input_dev->keybit);

        if (analog->mask & ANALOG_BTNS_CHF)
                for (i = 0; i < 2; i++)
                        set_bit(analog->buttons[j++], input_dev->keybit);

        if (analog->mask & ANALOG_HBTN_CHF)
                for (i = 0; i < 4; i++)
                        set_bit(analog->buttons[j++], input_dev->keybit);

        for (i = 0; i < 4; i++)
                if (analog->mask & (ANALOG_BTN_TL << i))
                        set_bit(analog_pads[i], input_dev->keybit);

        analog_decode(analog, port->axes, port->initial, port->buttons);

        error = input_register_device(analog->dev);
        if (error) {
                input_free_device(analog->dev);
                return error;
        }

        return 0;
}

/*
 * analog_init_devices() sets up device-specific values and registers the input devices.
 */

static int analog_init_masks(struct analog_port *port)
{
        int i;
        struct analog *analog = port->analog;
        int max[4];

        if (!port->mask)
                return -1;

        if ((port->mask & 3) != 3 && port->mask != 0xc) {
                printk(KERN_WARNING "analog.c: Unknown joystick device found  "
                        "(data=%#x, %s), probably not analog joystick.\n",
                        port->mask, port->gameport->phys);
                return -1;
        }


        i = analog_options[0]; /* FIXME !!! - need to specify options for different ports */

        analog[0].mask = i & 0xfffff;

        analog[0].mask &= ~(ANALOG_AXES_STD | ANALOG_HAT_FCS | ANALOG_BTNS_GAMEPAD)
                        | port->mask | ((port->mask << 8) & ANALOG_HAT_FCS)
                        | ((port->mask << 10) & ANALOG_BTNS_TLR) | ((port->mask << 12) & ANALOG_BTNS_TLR2);

        analog[0].mask &= ~(ANALOG_HAT2_CHF)
                        | ((analog[0].mask & ANALOG_HBTN_CHF) ? 0 : ANALOG_HAT2_CHF);

        analog[0].mask &= ~(ANALOG_THROTTLE | ANALOG_BTN_TR | ANALOG_BTN_TR2)
                        | ((~analog[0].mask & ANALOG_HAT_FCS) >> 8)
                        | ((~analog[0].mask & ANALOG_HAT_FCS) << 2)
                        | ((~analog[0].mask & ANALOG_HAT_FCS) << 4);

        analog[0].mask &= ~(ANALOG_THROTTLE | ANALOG_RUDDER)
                        | (((~analog[0].mask & ANALOG_BTNS_TLR ) >> 10)
                        &  ((~analog[0].mask & ANALOG_BTNS_TLR2) >> 12));

        analog[1].mask = ((i >> 20) & 0xff) | ((i >> 12) & 0xf0000);

        analog[1].mask &= (analog[0].mask & ANALOG_EXTENSIONS) ? ANALOG_GAMEPAD
                        : (((ANALOG_BTNS_STD | port->mask) & ~analog[0].mask) | ANALOG_GAMEPAD);

        if (port->cooked) {

                for (i = 0; i < 4; i++) max[i] = port->axes[i] << 1;

                if ((analog[0].mask & 0x7) == 0x7) max[2] = (max[0] + max[1]) >> 1;
                if ((analog[0].mask & 0xb) == 0xb) max[3] = (max[0] + max[1]) >> 1;
                if ((analog[0].mask & ANALOG_BTN_TL) && !(analog[0].mask & ANALOG_BTN_TL2)) max[2] >>= 1;
                if ((analog[0].mask & ANALOG_BTN_TR) && !(analog[0].mask & ANALOG_BTN_TR2)) max[3] >>= 1;
                if ((analog[0].mask & ANALOG_HAT_FCS)) max[3] >>= 1;

                gameport_calibrate(port->gameport, port->axes, max);
        }

        for (i = 0; i < 4; i++)
                port->initial[i] = port->axes[i];

        return -!(analog[0].mask || analog[1].mask);
}

static int analog_init_port(struct gameport *gameport, struct gameport_driver *drv, struct analog_port *port)
{
        int i, t, u, v;

        port->gameport = gameport;

        gameport_set_drvdata(gameport, port);

        if (!gameport_open(gameport, drv, GAMEPORT_MODE_RAW)) {

                analog_calibrate_timer(port);

                gameport_trigger(gameport);
                t = gameport_read(gameport);
                msleep(ANALOG_MAX_TIME);
                port->mask = (gameport_read(gameport) ^ t) & t & 0xf;
                port->fuzz = (NSEC_PER_MSEC * ANALOG_FUZZ_MAGIC) / port->loop / 1000 + ANALOG_FUZZ_BITS;

                for (i = 0; i < ANALOG_INIT_RETRIES; i++) {
                        if (!analog_cooked_read(port))
                                break;
                        msleep(ANALOG_MAX_TIME);
                }

                u = v = 0;

                msleep(ANALOG_MAX_TIME);
                t = gameport_time(gameport, ANALOG_MAX_TIME * 1000);
                gameport_trigger(gameport);
                while ((gameport_read(port->gameport) & port->mask) && (u < t))
                        u++;
                udelay(ANALOG_SAITEK_DELAY);
                t = gameport_time(gameport, ANALOG_SAITEK_TIME);
                gameport_trigger(gameport);
                while ((gameport_read(port->gameport) & port->mask) && (v < t))
                        v++;

                if (v < (u >> 1)) { /* FIXME - more than one port */
                        analog_options[0] |= /* FIXME - more than one port */
                                ANALOG_SAITEK | ANALOG_BTNS_CHF | ANALOG_HBTN_CHF | ANALOG_HAT1_CHF;
                        return 0;
                }

                gameport_close(gameport);
        }

        if (!gameport_open(gameport, drv, GAMEPORT_MODE_COOKED)) {

                for (i = 0; i < ANALOG_INIT_RETRIES; i++)
                        if (!gameport_cooked_read(gameport, port->axes, &port->buttons))
                                break;
                for (i = 0; i < 4; i++)
                        if (port->axes[i] != -1)
                                port->mask |= 1 << i;

                port->fuzz = gameport->fuzz;
                port->cooked = 1;
                return 0;
        }

        return gameport_open(gameport, drv, GAMEPORT_MODE_RAW);
}

static int analog_connect(struct gameport *gameport, struct gameport_driver *drv)
{
        struct analog_port *port;
        int i;
        int err;

        port = kzalloc_obj(*port);
        if (!port)
                return -ENOMEM;

        err = analog_init_port(gameport, drv, port);
        if (err)
                goto fail1;

        err = analog_init_masks(port);
        if (err)
                goto fail2;

        gameport_set_poll_handler(gameport, analog_poll);
        gameport_set_poll_interval(gameport, 10);

        for (i = 0; i < 2; i++)
                if (port->analog[i].mask) {
                        err = analog_init_device(port, port->analog + i, i);
                        if (err)
                                goto fail3;
                }

        return 0;

 fail3: while (--i >= 0)
                if (port->analog[i].mask)
                        input_unregister_device(port->analog[i].dev);
 fail2: gameport_close(gameport);
 fail1: gameport_set_drvdata(gameport, NULL);
        kfree(port);
        return err;
}

static void analog_disconnect(struct gameport *gameport)
{
        struct analog_port *port = gameport_get_drvdata(gameport);
        int i;

        for (i = 0; i < 2; i++)
                if (port->analog[i].mask)
                        input_unregister_device(port->analog[i].dev);
        gameport_close(gameport);
        gameport_set_drvdata(gameport, NULL);
        printk(KERN_INFO "analog.c: %d out of %d reads (%d%%) on %s failed\n",
                port->bads, port->reads, port->reads ? (port->bads * 100 / port->reads) : 0,
                port->gameport->phys);
        kfree(port);
}

struct analog_types {
        char *name;
        int value;
};

static struct analog_types analog_types[] = {
        { "none",       0x00000000 },
        { "auto",       0x000000ff },
        { "2btn",       0x0000003f },
        { "y-joy",      0x0cc00033 },
        { "y-pad",      0x8cc80033 },
        { "fcs",        0x000008f7 },
        { "chf",        0x000002ff },
        { "fullchf",    0x000007ff },
        { "gamepad",    0x000830f3 },
        { "gamepad8",   0x0008f0f3 },
        { NULL, 0 }
};

static void analog_parse_options(void)
{
        int i, j;
        char *end;

        for (i = 0; i < js_nargs; i++) {

                for (j = 0; analog_types[j].name; j++)
                        if (!strcmp(analog_types[j].name, js[i])) {
                                analog_options[i] = analog_types[j].value;
                                break;
                        }
                if (analog_types[j].name) continue;

                analog_options[i] = simple_strtoul(js[i], &end, 0);
                if (end != js[i]) continue;

                analog_options[i] = 0xff;
                if (!strlen(js[i])) continue;

                printk(KERN_WARNING "analog.c: Bad config for port %d - \"%s\"\n", i, js[i]);
        }

        for (; i < ANALOG_PORTS; i++)
                analog_options[i] = 0xff;
}

/*
 * The gameport device structure.
 */

static struct gameport_driver analog_drv = {
        .driver         = {
                .name   = "analog",
        },
        .description    = DRIVER_DESC,
        .connect        = analog_connect,
        .disconnect     = analog_disconnect,
};

static int __init analog_init(void)
{
        analog_parse_options();
        return gameport_register_driver(&analog_drv);
}

static void __exit analog_exit(void)
{
        gameport_unregister_driver(&analog_drv);
}

module_init(analog_init);
module_exit(analog_exit);