root/sound/drivers/mpu401/mpu401.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Driver for generic MPU-401 boards (UART mode only)
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  Copyright (c) 2004 by Castet Matthieu <castet.matthieu@free.fr>
 */

#include <linux/init.h>
#include <linux/pnp.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/mpu401.h>
#include <sound/initval.h>

MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("MPU-401 UART");
MODULE_LICENSE("GPL");

static int index[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = -2}; /* exclude the first card */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;       /* ID for this card */
static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE; /* Enable this card */
#ifdef CONFIG_PNP
static bool pnp[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
#endif
static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT;     /* MPU-401 port number */
static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ;        /* MPU-401 IRQ */
static bool uart_enter[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};

module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for MPU-401 device.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for MPU-401 device.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable MPU-401 device.");
#ifdef CONFIG_PNP
module_param_array(pnp, bool, NULL, 0444);
MODULE_PARM_DESC(pnp, "PnP detection for MPU-401 device.");
#endif
module_param_hw_array(port, long, ioport, NULL, 0444);
MODULE_PARM_DESC(port, "Port # for MPU-401 device.");
module_param_hw_array(irq, int, irq, NULL, 0444);
MODULE_PARM_DESC(irq, "IRQ # for MPU-401 device.");
module_param_array(uart_enter, bool, NULL, 0444);
MODULE_PARM_DESC(uart_enter, "Issue UART_ENTER command at open.");

static struct platform_device *platform_devices[SNDRV_CARDS];
static int pnp_registered;
static unsigned int snd_mpu401_devices;

static int snd_mpu401_create(struct device *devptr, int dev,
                             struct snd_card **rcard)
{
        struct snd_card *card;
        int err;

        if (!uart_enter[dev])
                dev_err(devptr, "the uart_enter option is obsolete; remove it\n");

        *rcard = NULL;
        err = snd_devm_card_new(devptr, index[dev], id[dev], THIS_MODULE,
                                0, &card);
        if (err < 0)
                return err;
        strscpy(card->driver, "MPU-401 UART");
        strscpy(card->shortname, card->driver);
        sprintf(card->longname, "%s at %#lx, ", card->shortname, port[dev]);
        if (irq[dev] >= 0) {
                sprintf(card->longname + strlen(card->longname), "irq %d", irq[dev]);
        } else {
                strcat(card->longname, "polled");
        }

        err = snd_mpu401_uart_new(card, 0, MPU401_HW_MPU401, port[dev], 0,
                                  irq[dev], NULL);
        if (err < 0) {
                dev_err(devptr, "MPU401 not detected at 0x%lx\n", port[dev]);
                return err;
        }

        *rcard = card;
        return 0;
}

static int snd_mpu401_probe(struct platform_device *devptr)
{
        int dev = devptr->id;
        int err;
        struct snd_card *card;

        if (port[dev] == SNDRV_AUTO_PORT) {
                dev_err(&devptr->dev, "specify port\n");
                return -EINVAL;
        }
        if (irq[dev] == SNDRV_AUTO_IRQ) {
                dev_err(&devptr->dev, "specify or disable IRQ\n");
                return -EINVAL;
        }
        err = snd_mpu401_create(&devptr->dev, dev, &card);
        if (err < 0)
                return err;
        err = snd_card_register(card);
        if (err < 0)
                return err;
        platform_set_drvdata(devptr, card);
        return 0;
}

#define SND_MPU401_DRIVER       "snd_mpu401"

static struct platform_driver snd_mpu401_driver = {
        .probe          = snd_mpu401_probe,
        .driver         = {
                .name   = SND_MPU401_DRIVER,
        },
};


#ifdef CONFIG_PNP

#define IO_EXTENT 2

static const struct pnp_device_id snd_mpu401_pnpids[] = {
        { .id = "PNPb006" },
        { .id = "" }
};

MODULE_DEVICE_TABLE(pnp, snd_mpu401_pnpids);

static int snd_mpu401_pnp(int dev, struct pnp_dev *device,
                          const struct pnp_device_id *id)
{
        if (!pnp_port_valid(device, 0) ||
            pnp_port_flags(device, 0) & IORESOURCE_DISABLED) {
                dev_err(&device->dev, "no PnP port\n");
                return -ENODEV;
        }
        if (pnp_port_len(device, 0) < IO_EXTENT) {
                dev_err(&device->dev, "PnP port length is %llu, expected %d\n",
                           (unsigned long long)pnp_port_len(device, 0),
                           IO_EXTENT);
                return -ENODEV;
        }
        port[dev] = pnp_port_start(device, 0);

        if (!pnp_irq_valid(device, 0) ||
            pnp_irq_flags(device, 0) & IORESOURCE_DISABLED) {
                dev_warn(&device->dev, "no PnP irq, using polling\n");
                irq[dev] = -1;
        } else {
                irq[dev] = pnp_irq(device, 0);
        }
        return 0;
}

static int snd_mpu401_pnp_probe(struct pnp_dev *pnp_dev,
                                const struct pnp_device_id *id)
{
        static int dev;
        struct snd_card *card;
        int err;

        for ( ; dev < SNDRV_CARDS; ++dev) {
                if (!enable[dev] || !pnp[dev])
                        continue;
                err = snd_mpu401_pnp(dev, pnp_dev, id);
                if (err < 0)
                        return err;
                err = snd_mpu401_create(&pnp_dev->dev, dev, &card);
                if (err < 0)
                        return err;
                err = snd_card_register(card);
                if (err < 0)
                        return err;
                pnp_set_drvdata(pnp_dev, card);
                snd_mpu401_devices++;
                ++dev;
                return 0;
        }
        return -ENODEV;
}

static struct pnp_driver snd_mpu401_pnp_driver = {
        .name = "mpu401",
        .id_table = snd_mpu401_pnpids,
        .probe = snd_mpu401_pnp_probe,
};
#else
static struct pnp_driver snd_mpu401_pnp_driver;
#endif

static void snd_mpu401_unregister_all(void)
{
        int i;

        if (pnp_registered)
                pnp_unregister_driver(&snd_mpu401_pnp_driver);
        for (i = 0; i < ARRAY_SIZE(platform_devices); ++i)
                platform_device_unregister(platform_devices[i]);
        platform_driver_unregister(&snd_mpu401_driver);
}

static int __init alsa_card_mpu401_init(void)
{
        int i, err;

        err = platform_driver_register(&snd_mpu401_driver);
        if (err < 0)
                return err;

        for (i = 0; i < SNDRV_CARDS; i++) {
                struct platform_device *device;
                if (! enable[i])
                        continue;
#ifdef CONFIG_PNP
                if (pnp[i])
                        continue;
#endif
                device = platform_device_register_simple(SND_MPU401_DRIVER,
                                                         i, NULL, 0);
                if (IS_ERR(device))
                        continue;
                if (!platform_get_drvdata(device)) {
                        platform_device_unregister(device);
                        continue;
                }
                platform_devices[i] = device;
                snd_mpu401_devices++;
        }
        err = pnp_register_driver(&snd_mpu401_pnp_driver);
        if (!err)
                pnp_registered = 1;

        if (!snd_mpu401_devices) {
#ifdef MODULE
                pr_err("MPU-401 device not found or device busy\n");
#endif
                snd_mpu401_unregister_all();
                return -ENODEV;
        }
        return 0;
}

static void __exit alsa_card_mpu401_exit(void)
{
        snd_mpu401_unregister_all();
}

module_init(alsa_card_mpu401_init)
module_exit(alsa_card_mpu401_exit)