// SPDX-License-Identifier: GPL-2.0-only
/*
 * Zoltrix Radio Plus driver
 * Copyright 1998 C. van Schaik <carl@leg.uct.ac.za>
 *
 * BUGS
 *  Due to the inconsistency in reading from the signal flags
 *  it is difficult to get an accurate tuned signal.
 *
 *  It seems that the card is not linear to 0 volume. It cuts off
 *  at a low volume, and it is not possible (at least I have not found)
 *  to get fine volume control over the low volume range.
 *
 *  Some code derived from code by Romolo Manfredini
 *                                 romolo@bicnet.it
 *
 * 1999-05-06 - (C. van Schaik)
 *            - Make signal strength and stereo scans
 *              kinder to cpu while in delay
 * 1999-01-05 - (C. van Schaik)
 *            - Changed tuning to 1/160Mhz accuracy
 *            - Added stereo support
 *              (card defaults to stereo)
 *              (can explicitly force mono on the card)
 *              (can detect if station is in stereo)
 *            - Added unmute function
 *            - Reworked ioctl functions
 * 2002-07-15 - Fix Stereo typo
 *
 * 2006-07-24 - Converted to V4L2 API
 *              by Mauro Carvalho Chehab <mchehab@kernel.org>
 *
 * Converted to the radio-isa framework by Hans Verkuil <hans.verkuil@cisco.com>
 *
 * Note that this is the driver for the Zoltrix Radio Plus.
 * This driver does not work for the Zoltrix Radio Plus 108 or the
 * Zoltrix Radio Plus for Windows.
 *
 * Fully tested with the Keene USB FM Transmitter and the v4l2-compliance tool.
 */

#include <linux/module.h>       /* Modules                        */
#include <linux/init.h>         /* Initdata                       */
#include <linux/ioport.h>       /* request_region                 */
#include <linux/delay.h>        /* udelay, msleep                 */
#include <linux/videodev2.h>    /* kernel radio structs           */
#include <linux/mutex.h>
#include <linux/io.h>           /* outb, outb_p                   */
#include <linux/slab.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>
#include "radio-isa.h"

MODULE_AUTHOR("C. van Schaik");
MODULE_DESCRIPTION("A driver for the Zoltrix Radio Plus.");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.1.99");

#ifndef CONFIG_RADIO_ZOLTRIX_PORT
#define CONFIG_RADIO_ZOLTRIX_PORT -1
#endif

#define ZOLTRIX_MAX 2

static int io[ZOLTRIX_MAX] = { [0] = CONFIG_RADIO_ZOLTRIX_PORT,
                               [1 ... (ZOLTRIX_MAX - 1)] = -1 };
static int radio_nr[ZOLTRIX_MAX] = { [0 ... (ZOLTRIX_MAX - 1)] = -1 };

module_param_array(io, int, NULL, 0444);
MODULE_PARM_DESC(io, "I/O addresses of the Zoltrix Radio Plus card (0x20c or 0x30c)");
module_param_array(radio_nr, int, NULL, 0444);
MODULE_PARM_DESC(radio_nr, "Radio device numbers");

struct zoltrix {
        struct radio_isa_card isa;
        int curvol;
        bool muted;
};

static struct radio_isa_card *zoltrix_alloc(void)
{
        struct zoltrix *zol = kzalloc(sizeof(*zol), GFP_KERNEL);

        return zol ? &zol->isa : NULL;
}

static int zoltrix_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
{
        struct zoltrix *zol = container_of(isa, struct zoltrix, isa);

        zol->curvol = vol;
        zol->muted = mute;
        if (mute || vol == 0) {
                outb(0, isa->io);
                outb(0, isa->io);
                inb(isa->io + 3);            /* Zoltrix needs to be read to confirm */
                return 0;
        }

        outb(vol - 1, isa->io);
        msleep(10);
        inb(isa->io + 2);
        return 0;
}

/* tunes the radio to the desired frequency */
static int zoltrix_s_frequency(struct radio_isa_card *isa, u32 freq)
{
        struct zoltrix *zol = container_of(isa, struct zoltrix, isa);
        struct v4l2_device *v4l2_dev = &isa->v4l2_dev;
        unsigned long long bitmask, f, m;
        bool stereo = isa->stereo;
        int i;

        if (freq == 0) {
                v4l2_warn(v4l2_dev, "cannot set a frequency of 0.\n");
                return -EINVAL;
        }

        m = (freq / 160 - 8800) * 2;
        f = (unsigned long long)m + 0x4d1c;

        bitmask = 0xc480402c10080000ull;
        i = 45;

        outb(0, isa->io);
        outb(0, isa->io);
        inb(isa->io + 3);            /* Zoltrix needs to be read to confirm */

        outb(0x40, isa->io);
        outb(0xc0, isa->io);

        bitmask = (bitmask ^ ((f & 0xff) << 47) ^ ((f & 0xff00) << 30) ^ (stereo << 31));
        while (i--) {
                if ((bitmask & 0x8000000000000000ull) != 0) {
                        outb(0x80, isa->io);
                        udelay(50);
                        outb(0x00, isa->io);
                        udelay(50);
                        outb(0x80, isa->io);
                        udelay(50);
                } else {
                        outb(0xc0, isa->io);
                        udelay(50);
                        outb(0x40, isa->io);
                        udelay(50);
                        outb(0xc0, isa->io);
                        udelay(50);
                }
                bitmask *= 2;
        }
        /* termination sequence */
        outb(0x80, isa->io);
        outb(0xc0, isa->io);
        outb(0x40, isa->io);
        udelay(1000);
        inb(isa->io + 2);
        udelay(1000);

        return zoltrix_s_mute_volume(isa, zol->muted, zol->curvol);
}

/* Get signal strength */
static u32 zoltrix_g_rxsubchans(struct radio_isa_card *isa)
{
        struct zoltrix *zol = container_of(isa, struct zoltrix, isa);
        int a, b;

        outb(0x00, isa->io);         /* This stuff I found to do nothing */
        outb(zol->curvol, isa->io);
        msleep(20);

        a = inb(isa->io);
        msleep(10);
        b = inb(isa->io);

        return (a == b && a == 0xcf) ?
                V4L2_TUNER_SUB_STEREO : V4L2_TUNER_SUB_MONO;
}

static u32 zoltrix_g_signal(struct radio_isa_card *isa)
{
        struct zoltrix *zol = container_of(isa, struct zoltrix, isa);
        int a, b;

        outb(0x00, isa->io);         /* This stuff I found to do nothing */
        outb(zol->curvol, isa->io);
        msleep(20);

        a = inb(isa->io);
        msleep(10);
        b = inb(isa->io);

        if (a != b)
                return 0;

        /* I found this out by playing with a binary scanner on the card io */
        return (a == 0xcf || a == 0xdf || a == 0xef) ? 0xffff : 0;
}

static int zoltrix_s_stereo(struct radio_isa_card *isa, bool stereo)
{
        return zoltrix_s_frequency(isa, isa->freq);
}

static const struct radio_isa_ops zoltrix_ops = {
        .alloc = zoltrix_alloc,
        .s_mute_volume = zoltrix_s_mute_volume,
        .s_frequency = zoltrix_s_frequency,
        .s_stereo = zoltrix_s_stereo,
        .g_rxsubchans = zoltrix_g_rxsubchans,
        .g_signal = zoltrix_g_signal,
};

static const int zoltrix_ioports[] = { 0x20c, 0x30c };

static struct radio_isa_driver zoltrix_driver = {
        .driver = {
                .match          = radio_isa_match,
                .probe          = radio_isa_probe,
                .remove         = radio_isa_remove,
                .driver         = {
                        .name   = "radio-zoltrix",
                },
        },
        .io_params = io,
        .radio_nr_params = radio_nr,
        .io_ports = zoltrix_ioports,
        .num_of_io_ports = ARRAY_SIZE(zoltrix_ioports),
        .region_size = 2,
        .card = "Zoltrix Radio Plus",
        .ops = &zoltrix_ops,
        .has_stereo = true,
        .max_volume = 15,
};

static int __init zoltrix_init(void)
{
        return isa_register_driver(&zoltrix_driver.driver, ZOLTRIX_MAX);
}

static void __exit zoltrix_exit(void)
{
        isa_unregister_driver(&zoltrix_driver.driver);
}

module_init(zoltrix_init);
module_exit(zoltrix_exit);