// SPDX-License-Identifier: GPL-2.0-only
/*
 * GemTek radio card driver
 *
 * Copyright 1998 Jonas Munsin <jmunsin@iki.fi>
 *
 * GemTek hasn't released any specs on the card, so the protocol had to
 * be reverse engineered with dosemu.
 *
 * Besides the protocol changes, this is mostly a copy of:
 *
 *    RadioTrack II driver for Linux radio support (C) 1998 Ben Pfaff
 *
 *    Based on RadioTrack I/RadioReveal (C) 1997 M. Kirkwood
 *    Converted to new API by Alan Cox <alan@lxorguk.ukuu.org.uk>
 *    Various bugfixes and enhancements by Russell Kroll <rkroll@exploits.org>
 *
 * Converted to the radio-isa framework by Hans Verkuil <hverkuil@kernel.org>
 * Converted to V4L2 API by Mauro Carvalho Chehab <mchehab@kernel.org>
 *
 * Note: this card seems to swap the left and right audio channels!
 *
 * 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                       */
#include <linux/videodev2.h>    /* kernel radio structs         */
#include <linux/mutex.h>
#include <linux/io.h>           /* outb, outb_p                 */
#include <linux/pnp.h>
#include <linux/slab.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-device.h>
#include "radio-isa.h"

/*
 * Module info.
 */

MODULE_AUTHOR("Jonas Munsin, Pekka Seppänen <pexu@kapsi.fi>");
MODULE_DESCRIPTION("A driver for the GemTek Radio card.");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0.0");

/*
 * Module params.
 */

#ifndef CONFIG_RADIO_GEMTEK_PORT
#define CONFIG_RADIO_GEMTEK_PORT -1
#endif
#ifndef CONFIG_RADIO_GEMTEK_PROBE
#define CONFIG_RADIO_GEMTEK_PROBE 1
#endif

#define GEMTEK_MAX 4

static bool probe = CONFIG_RADIO_GEMTEK_PROBE;
static bool hardmute;
static int io[GEMTEK_MAX] = { [0] = CONFIG_RADIO_GEMTEK_PORT,
                              [1 ... (GEMTEK_MAX - 1)] = -1 };
static int radio_nr[GEMTEK_MAX] = { [0 ... (GEMTEK_MAX - 1)] = -1 };

module_param(probe, bool, 0444);
MODULE_PARM_DESC(probe, "Enable automatic device probing.");

module_param(hardmute, bool, 0644);
MODULE_PARM_DESC(hardmute, "Enable 'hard muting' by shutting down PLL, may reduce static noise.");

module_param_array(io, int, NULL, 0444);
MODULE_PARM_DESC(io, "Force I/O ports for the GemTek Radio card if automatic probing is disabled or fails. The most common I/O ports are: 0x20c 0x30c, 0x24c or 0x34c (0x20c, 0x248 and 0x28c have been reported to work for the combined sound/radiocard).");

module_param_array(radio_nr, int, NULL, 0444);
MODULE_PARM_DESC(radio_nr, "Radio device numbers");

/*
 * Frequency calculation constants.  Intermediate frequency 10.52 MHz (nominal
 * value 10.7 MHz), reference divisor 6.39 kHz (nominal 6.25 kHz).
 */
#define FSCALE          8
#define IF_OFFSET       ((unsigned int)(10.52 * 16000 * (1<<FSCALE)))
#define REF_FREQ        ((unsigned int)(6.39 * 16 * (1<<FSCALE)))

#define GEMTEK_CK               0x01    /* Clock signal                 */
#define GEMTEK_DA               0x02    /* Serial data                  */
#define GEMTEK_CE               0x04    /* Chip enable                  */
#define GEMTEK_NS               0x08    /* No signal                    */
#define GEMTEK_MT               0x10    /* Line mute                    */
#define GEMTEK_STDF_3_125_KHZ   0x01    /* Standard frequency 3.125 kHz */
#define GEMTEK_PLL_OFF          0x07    /* PLL off                      */

#define BU2614_BUS_SIZE 32      /* BU2614 / BU2614FS bus size           */

#define SHORT_DELAY 5           /* usec */
#define LONG_DELAY 75           /* usec */

struct gemtek {
        struct radio_isa_card isa;
        bool muted;
        u32 bu2614data;
};

#define BU2614_FREQ_BITS        16 /* D0..D15, Frequency data           */
#define BU2614_PORT_BITS        3 /* P0..P2, Output port control data   */
#define BU2614_VOID_BITS        4 /* unused                             */
#define BU2614_FMES_BITS        1 /* CT, Frequency measurement beginning data */
#define BU2614_STDF_BITS        3 /* R0..R2, Standard frequency data    */
#define BU2614_SWIN_BITS        1 /* S, Switch between FMIN / AMIN      */
#define BU2614_SWAL_BITS        1 /* PS, Swallow counter division (AMIN only)*/
#define BU2614_VOID2_BITS       1 /* unused                             */
#define BU2614_FMUN_BITS        1 /* GT, Frequency measurement time & unlock */
#define BU2614_TEST_BITS        1 /* TS, Test data is input             */

#define BU2614_FREQ_SHIFT       0
#define BU2614_PORT_SHIFT       (BU2614_FREQ_BITS + BU2614_FREQ_SHIFT)
#define BU2614_VOID_SHIFT       (BU2614_PORT_BITS + BU2614_PORT_SHIFT)
#define BU2614_FMES_SHIFT       (BU2614_VOID_BITS + BU2614_VOID_SHIFT)
#define BU2614_STDF_SHIFT       (BU2614_FMES_BITS + BU2614_FMES_SHIFT)
#define BU2614_SWIN_SHIFT       (BU2614_STDF_BITS + BU2614_STDF_SHIFT)
#define BU2614_SWAL_SHIFT       (BU2614_SWIN_BITS + BU2614_SWIN_SHIFT)
#define BU2614_VOID2_SHIFT      (BU2614_SWAL_BITS + BU2614_SWAL_SHIFT)
#define BU2614_FMUN_SHIFT       (BU2614_VOID2_BITS + BU2614_VOID2_SHIFT)
#define BU2614_TEST_SHIFT       (BU2614_FMUN_BITS + BU2614_FMUN_SHIFT)

#define MKMASK(field)   (((1UL<<BU2614_##field##_BITS) - 1) << \
                        BU2614_##field##_SHIFT)
#define BU2614_PORT_MASK        MKMASK(PORT)
#define BU2614_FREQ_MASK        MKMASK(FREQ)
#define BU2614_VOID_MASK        MKMASK(VOID)
#define BU2614_FMES_MASK        MKMASK(FMES)
#define BU2614_STDF_MASK        MKMASK(STDF)
#define BU2614_SWIN_MASK        MKMASK(SWIN)
#define BU2614_SWAL_MASK        MKMASK(SWAL)
#define BU2614_VOID2_MASK       MKMASK(VOID2)
#define BU2614_FMUN_MASK        MKMASK(FMUN)
#define BU2614_TEST_MASK        MKMASK(TEST)

/*
 * Set data which will be sent to BU2614FS.
 */
#define gemtek_bu2614_set(dev, field, data) ((dev)->bu2614data = \
        ((dev)->bu2614data & ~field##_MASK) | ((data) << field##_SHIFT))

/*
 * Transmit settings to BU2614FS over GemTek IC.
 */
static void gemtek_bu2614_transmit(struct gemtek *gt)
{
        struct radio_isa_card *isa = &gt->isa;
        int i, bit, q, mute;

        mute = gt->muted ? GEMTEK_MT : 0x00;

        outb_p(mute | GEMTEK_CE | GEMTEK_DA | GEMTEK_CK, isa->io);
        udelay(LONG_DELAY);

        for (i = 0, q = gt->bu2614data; i < 32; i++, q >>= 1) {
                bit = (q & 1) ? GEMTEK_DA : 0;
                outb_p(mute | GEMTEK_CE | bit, isa->io);
                udelay(SHORT_DELAY);
                outb_p(mute | GEMTEK_CE | bit | GEMTEK_CK, isa->io);
                udelay(SHORT_DELAY);
        }

        outb_p(mute | GEMTEK_DA | GEMTEK_CK, isa->io);
        udelay(SHORT_DELAY);
}

/*
 * Calculate divisor from FM-frequency for BU2614FS (3.125 KHz STDF expected).
 */
static unsigned long gemtek_convfreq(unsigned long freq)
{
        return ((freq << FSCALE) + IF_OFFSET + REF_FREQ / 2) / REF_FREQ;
}

static struct radio_isa_card *gemtek_alloc(void)
{
        struct gemtek *gt = kzalloc_obj(*gt);

        if (gt)
                gt->muted = true;
        return gt ? &gt->isa : NULL;
}

/*
 * Set FM-frequency.
 */
static int gemtek_s_frequency(struct radio_isa_card *isa, u32 freq)
{
        struct gemtek *gt = container_of(isa, struct gemtek, isa);

        if (hardmute && gt->muted)
                return 0;

        gemtek_bu2614_set(gt, BU2614_PORT, 0);
        gemtek_bu2614_set(gt, BU2614_FMES, 0);
        gemtek_bu2614_set(gt, BU2614_SWIN, 0);  /* FM-mode      */
        gemtek_bu2614_set(gt, BU2614_SWAL, 0);
        gemtek_bu2614_set(gt, BU2614_FMUN, 1);  /* GT bit set   */
        gemtek_bu2614_set(gt, BU2614_TEST, 0);
        gemtek_bu2614_set(gt, BU2614_STDF, GEMTEK_STDF_3_125_KHZ);
        gemtek_bu2614_set(gt, BU2614_FREQ, gemtek_convfreq(freq));
        gemtek_bu2614_transmit(gt);
        return 0;
}

/*
 * Set mute flag.
 */
static int gemtek_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
{
        struct gemtek *gt = container_of(isa, struct gemtek, isa);
        int i;

        gt->muted = mute;
        if (hardmute) {
                if (!mute)
                        return gemtek_s_frequency(isa, isa->freq);

                /* Turn off PLL, disable data output */
                gemtek_bu2614_set(gt, BU2614_PORT, 0);
                gemtek_bu2614_set(gt, BU2614_FMES, 0);  /* CT bit off   */
                gemtek_bu2614_set(gt, BU2614_SWIN, 0);  /* FM-mode      */
                gemtek_bu2614_set(gt, BU2614_SWAL, 0);
                gemtek_bu2614_set(gt, BU2614_FMUN, 0);  /* GT bit off   */
                gemtek_bu2614_set(gt, BU2614_TEST, 0);
                gemtek_bu2614_set(gt, BU2614_STDF, GEMTEK_PLL_OFF);
                gemtek_bu2614_set(gt, BU2614_FREQ, 0);
                gemtek_bu2614_transmit(gt);
                return 0;
        }

        /* Read bus contents (CE, CK and DA). */
        i = inb_p(isa->io);
        /* Write it back with mute flag set. */
        outb_p((i >> 5) | (mute ? GEMTEK_MT : 0), isa->io);
        udelay(SHORT_DELAY);
        return 0;
}

static u32 gemtek_g_rxsubchans(struct radio_isa_card *isa)
{
        if (inb_p(isa->io) & GEMTEK_NS)
                return V4L2_TUNER_SUB_MONO;
        return V4L2_TUNER_SUB_STEREO;
}

/*
 * Check if requested card acts like GemTek Radio card.
 */
static bool gemtek_probe(struct radio_isa_card *isa, int io)
{
        int i, q;

        q = inb_p(io);  /* Read bus contents before probing. */
        /* Try to turn on CE, CK and DA respectively and check if card responds
           properly. */
        for (i = 0; i < 3; ++i) {
                outb_p(1 << i, io);
                udelay(SHORT_DELAY);

                if ((inb_p(io) & ~GEMTEK_NS) != (0x17 | (1 << (i + 5))))
                        return false;
        }
        outb_p(q >> 5, io);     /* Write bus contents back. */
        udelay(SHORT_DELAY);
        return true;
}

static const struct radio_isa_ops gemtek_ops = {
        .alloc = gemtek_alloc,
        .probe = gemtek_probe,
        .s_mute_volume = gemtek_s_mute_volume,
        .s_frequency = gemtek_s_frequency,
        .g_rxsubchans = gemtek_g_rxsubchans,
};

static const int gemtek_ioports[] = { 0x20c, 0x30c, 0x24c, 0x34c, 0x248, 0x28c };

#ifdef CONFIG_PNP
static const struct pnp_device_id gemtek_pnp_devices[] = {
        /* AOpen FX-3D/Pro Radio */
        {.id = "ADS7183", .driver_data = 0},
        {.id = ""}
};

MODULE_DEVICE_TABLE(pnp, gemtek_pnp_devices);
#endif

static struct radio_isa_driver gemtek_driver = {
        .driver = {
                .match          = radio_isa_match,
                .probe          = radio_isa_probe,
                .remove         = radio_isa_remove,
                .driver         = {
                        .name   = "radio-gemtek",
                },
        },
#ifdef CONFIG_PNP
        .pnp_driver = {
                .name           = "radio-gemtek",
                .id_table       = gemtek_pnp_devices,
                .probe          = radio_isa_pnp_probe,
                .remove         = radio_isa_pnp_remove,
        },
#endif
        .io_params = io,
        .radio_nr_params = radio_nr,
        .io_ports = gemtek_ioports,
        .num_of_io_ports = ARRAY_SIZE(gemtek_ioports),
        .region_size = 1,
        .card = "GemTek Radio",
        .ops = &gemtek_ops,
        .has_stereo = true,
};

static int __init gemtek_init(void)
{
        gemtek_driver.probe = probe;
#ifdef CONFIG_PNP
        pnp_register_driver(&gemtek_driver.pnp_driver);
#endif
        return isa_register_driver(&gemtek_driver.driver, GEMTEK_MAX);
}

static void __exit gemtek_exit(void)
{
        hardmute = true;        /* Turn off PLL */
#ifdef CONFIG_PNP
        pnp_unregister_driver(&gemtek_driver.pnp_driver);
#endif
        isa_unregister_driver(&gemtek_driver.driver);
}

module_init(gemtek_init);
module_exit(gemtek_exit);