// SPDX-License-Identifier: GPL-2.0-only
/* Terratec ActiveRadio ISA Standalone card driver for Linux radio support
 * (c) 1999 R. Offermanns (rolf@offermanns.de)
 * based on the aimslab radio driver from M. Kirkwood
 * many thanks to Michael Becker and Friedhelm Birth (from TerraTec)
 *
 *
 * History:
 * 1999-05-21   First preview release
 *
 *  Notes on the hardware:
 *  There are two "main" chips on the card:
 *  - Philips OM5610 (http://www-us.semiconductors.philips.com/acrobat/datasheets/OM5610_2.pdf)
 *  - Philips SAA6588 (http://www-us.semiconductors.philips.com/acrobat/datasheets/SAA6588_1.pdf)
 *  (you can get the datasheet at the above links)
 *
 *  Frequency control is done digitally -- ie out(port,encodefreq(95.8));
 *  Volume Control is done digitally
 *
 * Converted to the radio-isa framework by Hans Verkuil <hverkuil@kernel.org>
 * Converted to V4L2 API by Mauro Carvalho Chehab <mchehab@kernel.org>
 */

#include <linux/module.h>       /* Modules                      */
#include <linux/init.h>         /* Initdata                     */
#include <linux/ioport.h>       /* request_region               */
#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("R. Offermans & others");
MODULE_DESCRIPTION("A driver for the TerraTec ActiveRadio Standalone radio card.");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.1.99");

/* Note: there seems to be only one possible port (0x590), but without
   hardware this is hard to verify. For now, this is the only one we will
   support. */
static int io = 0x590;
static int radio_nr = -1;

module_param(radio_nr, int, 0444);
MODULE_PARM_DESC(radio_nr, "Radio device number");

#define WRT_DIS         0x00
#define CLK_OFF         0x00
#define IIC_DATA        0x01
#define IIC_CLK         0x02
#define DATA            0x04
#define CLK_ON          0x08
#define WRT_EN          0x10

static struct radio_isa_card *terratec_alloc(void)
{
        return kzalloc_obj(struct radio_isa_card);
}

static int terratec_s_mute_volume(struct radio_isa_card *isa, bool mute, int vol)
{
        int i;

        if (mute)
                vol = 0;
        vol = vol + (vol * 32); /* change both channels */
        for (i = 0; i < 8; i++) {
                if (vol & (0x80 >> i))
                        outb(0x80, isa->io + 1);
                else
                        outb(0x00, isa->io + 1);
        }
        return 0;
}


/* this is the worst part in this driver */
/* many more or less strange things are going on here, but hey, it works :) */

static int terratec_s_frequency(struct radio_isa_card *isa, u32 freq)
{
        int i;
        int temp;
        long rest;
        unsigned char buffer[25];               /* we have to bit shift 25 registers */

        freq = freq / 160;                      /* convert the freq. to a nice to handle value */
        memset(buffer, 0, sizeof(buffer));

        rest = freq * 10 + 10700;       /* I once had understood what is going on here */
                                        /* maybe some wise guy (friedhelm?) can comment this stuff */
        i = 13;
        temp = 102400;
        while (rest != 0) {
                if (rest % temp  == rest)
                        buffer[i] = 0;
                else {
                        buffer[i] = 1;
                        rest = rest - temp;
                }
                i--;
                temp = temp / 2;
        }

        for (i = 24; i > -1; i--) {     /* bit shift the values to the radiocard */
                if (buffer[i] == 1) {
                        outb(WRT_EN | DATA, isa->io);
                        outb(WRT_EN | DATA | CLK_ON, isa->io);
                        outb(WRT_EN | DATA, isa->io);
                } else {
                        outb(WRT_EN | 0x00, isa->io);
                        outb(WRT_EN | 0x00 | CLK_ON, isa->io);
                }
        }
        outb(0x00, isa->io);
        return 0;
}

static u32 terratec_g_signal(struct radio_isa_card *isa)
{
        /* bit set = no signal present  */
        return (inb(isa->io) & 2) ? 0 : 0xffff;
}

static const struct radio_isa_ops terratec_ops = {
        .alloc = terratec_alloc,
        .s_mute_volume = terratec_s_mute_volume,
        .s_frequency = terratec_s_frequency,
        .g_signal = terratec_g_signal,
};

static const int terratec_ioports[] = { 0x590 };

static struct radio_isa_driver terratec_driver = {
        .driver = {
                .match          = radio_isa_match,
                .probe          = radio_isa_probe,
                .remove         = radio_isa_remove,
                .driver         = {
                        .name   = "radio-terratec",
                },
        },
        .io_params = &io,
        .radio_nr_params = &radio_nr,
        .io_ports = terratec_ioports,
        .num_of_io_ports = ARRAY_SIZE(terratec_ioports),
        .region_size = 2,
        .card = "TerraTec ActiveRadio",
        .ops = &terratec_ops,
        .has_stereo = true,
        .max_volume = 10,
};

static int __init terratec_init(void)
{
        return isa_register_driver(&terratec_driver.driver, 1);
}

static void __exit terratec_exit(void)
{
        isa_unregister_driver(&terratec_driver.driver);
}

module_init(terratec_init);
module_exit(terratec_exit);