xref: /openbmc/linux/sound/drivers/portman2x4.c (revision da155d5b40587815a4397e1a69382fe2366d940b)

/*
 *   Driver for Midiman Portman2x4 parallel port midi interface
 *
 *   Copyright (c) by Levent Guendogdu <levon@feature-it.com>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * ChangeLog
 * Jan 24 2007 Matthias Koenig <mkoenig@suse.de>
 *      - cleanup and rewrite
 * Sep 30 2004 Tobias Gehrig <tobias@gehrig.tk>
 *      - source code cleanup
 * Sep 03 2004 Tobias Gehrig <tobias@gehrig.tk>
 *      - fixed compilation problem with alsa 1.0.6a (removed MODULE_CLASSES,
 *        MODULE_PARM_SYNTAX and changed MODULE_DEVICES to
 *        MODULE_SUPPORTED_DEVICE)
 * Mar 24 2004 Tobias Gehrig <tobias@gehrig.tk>
 *      - added 2.6 kernel support
 * Mar 18 2004 Tobias Gehrig <tobias@gehrig.tk>
 *      - added parport_unregister_driver to the startup routine if the driver fails to detect a portman
 *      - added support for all 4 output ports in portman_putmidi
 * Mar 17 2004 Tobias Gehrig <tobias@gehrig.tk>
 *      - added checks for opened input device in interrupt handler
 * Feb 20 2004 Tobias Gehrig <tobias@gehrig.tk>
 *      - ported from alsa 0.5 to 1.0
 */

#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/parport.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/rawmidi.h>
#include <sound/control.h>

#define CARD_NAME "Portman 2x4"
#define DRIVER_NAME "portman"
#define PLATFORM_DRIVER "snd_portman2x4"

static int index[SNDRV_CARDS]  = SNDRV_DEFAULT_IDX;
static char *id[SNDRV_CARDS]   = SNDRV_DEFAULT_STR;
static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;

static struct platform_device *platform_devices[SNDRV_CARDS];
static int device_count;

module_param_array(index, int, NULL, S_IRUGO);
MODULE_PARM_DESC(index, "Index value for " CARD_NAME " soundcard.");
module_param_array(id, charp, NULL, S_IRUGO);
MODULE_PARM_DESC(id, "ID string for " CARD_NAME " soundcard.");
module_param_array(enable, bool, NULL, S_IRUGO);
MODULE_PARM_DESC(enable, "Enable " CARD_NAME " soundcard.");

MODULE_AUTHOR("Levent Guendogdu, Tobias Gehrig, Matthias Koenig");
MODULE_DESCRIPTION("Midiman Portman2x4");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Midiman,Portman2x4}}");

/*********************************************************************
 * Chip specific
 *********************************************************************/
#define PORTMAN_NUM_INPUT_PORTS 2
#define PORTMAN_NUM_OUTPUT_PORTS 4

struct portman {
	spinlock_t reg_lock;
	struct snd_card *card;
	struct snd_rawmidi *rmidi;
	struct pardevice *pardev;
	int pardev_claimed;

	int open_count;
	int mode[PORTMAN_NUM_INPUT_PORTS];
	struct snd_rawmidi_substream *midi_input[PORTMAN_NUM_INPUT_PORTS];
};

static int portman_free(struct portman *pm)
{
	kfree(pm);
	return 0;
}

static int __devinit portman_create(struct snd_card *card,
				    struct pardevice *pardev,
				    struct portman **rchip)
{
	struct portman *pm;

	*rchip = NULL;

	pm = kzalloc(sizeof(struct portman), GFP_KERNEL);
	if (pm == NULL)
		return -ENOMEM;

	/* Init chip specific data */
	spin_lock_init(&pm->reg_lock);
	pm->card = card;
	pm->pardev = pardev;

	*rchip = pm;

	return 0;
}

/*********************************************************************
 * HW related constants
 *********************************************************************/

/* Standard PC parallel port status register equates. */
#define	PP_STAT_BSY   	0x80	/* Busy status.  Inverted. */
#define	PP_STAT_ACK   	0x40	/* Acknowledge.  Non-Inverted. */
#define	PP_STAT_POUT  	0x20	/* Paper Out.    Non-Inverted. */
#define	PP_STAT_SEL   	0x10	/* Select.       Non-Inverted. */
#define	PP_STAT_ERR   	0x08	/* Error.        Non-Inverted. */

/* Standard PC parallel port command register equates. */
#define	PP_CMD_IEN  	0x10	/* IRQ Enable.   Non-Inverted. */
#define	PP_CMD_SELI 	0x08	/* Select Input. Inverted. */
#define	PP_CMD_INIT 	0x04	/* Init Printer. Non-Inverted. */
#define	PP_CMD_FEED 	0x02	/* Auto Feed.    Inverted. */
#define	PP_CMD_STB      0x01	/* Strobe.       Inverted. */

/* Parallel Port Command Register as implemented by PCP2x4. */
#define	INT_EN	 	PP_CMD_IEN	/* Interrupt enable. */
#define	STROBE	        PP_CMD_STB	/* Command strobe. */

/* The parallel port command register field (b1..b3) selects the
 * various "registers" within the PC/P 2x4.  These are the internal
 * address of these "registers" that must be written to the parallel
 * port command register.
 */
#define	RXDATA0		(0 << 1)	/* PCP RxData channel 0. */
#define	RXDATA1		(1 << 1)	/* PCP RxData channel 1. */
#define	GEN_CTL		(2 << 1)	/* PCP General Control Register. */
#define	SYNC_CTL 	(3 << 1)	/* PCP Sync Control Register. */
#define	TXDATA0		(4 << 1)	/* PCP TxData channel 0. */
#define	TXDATA1		(5 << 1)	/* PCP TxData channel 1. */
#define	TXDATA2		(6 << 1)	/* PCP TxData channel 2. */
#define	TXDATA3		(7 << 1)	/* PCP TxData channel 3. */

/* Parallel Port Status Register as implemented by PCP2x4. */
#define	ESTB		PP_STAT_POUT	/* Echoed strobe. */
#define	INT_REQ         PP_STAT_ACK	/* Input data int request. */
#define	BUSY            PP_STAT_ERR	/* Interface Busy. */

/* Parallel Port Status Register BUSY and SELECT lines are multiplexed
 * between several functions.  Depending on which 2x4 "register" is
 * currently selected (b1..b3), the BUSY and SELECT lines are
 * assigned as follows:
 *
 *   SELECT LINE:                                                    A3 A2 A1
 *                                                                   --------
 */
#define	RXAVAIL		PP_STAT_SEL	/* Rx Available, channel 0.   0 0 0 */
//  RXAVAIL1    PP_STAT_SEL             /* Rx Available, channel 1.   0 0 1 */
#define	SYNC_STAT	PP_STAT_SEL	/* Reserved - Sync Status.    0 1 0 */
//                                      /* Reserved.                  0 1 1 */
#define	TXEMPTY		PP_STAT_SEL	/* Tx Empty, channel 0.       1 0 0 */
//      TXEMPTY1        PP_STAT_SEL     /* Tx Empty, channel 1.       1 0 1 */
//  TXEMPTY2    PP_STAT_SEL             /* Tx Empty, channel 2.       1 1 0 */
//  TXEMPTY3    PP_STAT_SEL             /* Tx Empty, channel 3.       1 1 1 */

/*   BUSY LINE:                                                      A3 A2 A1
 *                                                                   --------
 */
#define	RXDATA		PP_STAT_BSY	/* Rx Input Data, channel 0.  0 0 0 */
//      RXDATA1         PP_STAT_BSY     /* Rx Input Data, channel 1.  0 0 1 */
#define	SYNC_DATA       PP_STAT_BSY	/* Reserved - Sync Data.      0 1 0 */
					/* Reserved.                  0 1 1 */
#define	DATA_ECHO       PP_STAT_BSY	/* Parallel Port Data Echo.   1 0 0 */
#define	A0_ECHO         PP_STAT_BSY	/* Address 0 Echo.            1 0 1 */
#define	A1_ECHO         PP_STAT_BSY	/* Address 1 Echo.            1 1 0 */
#define	A2_ECHO         PP_STAT_BSY	/* Address 2 Echo.            1 1 1 */

#define PORTMAN2X4_MODE_INPUT_TRIGGERED	 0x01

/*********************************************************************
 * Hardware specific functions
 *********************************************************************/
static inline void portman_write_command(struct portman *pm, u8 value)
{
	parport_write_control(pm->pardev->port, value);
}

static inline u8 portman_read_command(struct portman *pm)
{
	return parport_read_control(pm->pardev->port);
}

static inline u8 portman_read_status(struct portman *pm)
{
	return parport_read_status(pm->pardev->port);
}

static inline u8 portman_read_data(struct portman *pm)
{
	return parport_read_data(pm->pardev->port);
}

static inline void portman_write_data(struct portman *pm, u8 value)
{
	parport_write_data(pm->pardev->port, value);
}

static void portman_write_midi(struct portman *pm,
			       int port, u8 mididata)
{
	int command = ((port + 4) << 1);

	/* Get entering data byte and port number in BL and BH respectively.
	 * Set up Tx Channel address field for use with PP Cmd Register.
	 * Store address field in BH register.
	 * Inputs:      AH = Output port number (0..3).
	 *              AL = Data byte.
	 *    command = TXDATA0 | INT_EN;
	 * Align port num with address field (b1...b3),
	 * set address for TXDatax, Strobe=0
	 */
	command |= INT_EN;

	/* Disable interrupts so that the process is not interrupted, then
	 * write the address associated with the current Tx channel to the
	 * PP Command Reg.  Do not set the Strobe signal yet.
	 */

	do {
		portman_write_command(pm, command);

		/* While the address lines settle, write parallel output data to
		 * PP Data Reg.  This has no effect until Strobe signal is asserted.
		 */

		portman_write_data(pm, mididata);

		/* If PCP channel's TxEmpty is set (TxEmpty is read through the PP
		 * Status Register), then go write data.  Else go back and wait.
		 */
	} while ((portman_read_status(pm) & TXEMPTY) != TXEMPTY);

	/* TxEmpty is set.  Maintain PC/P destination address and assert
	 * Strobe through the PP Command Reg.  This will Strobe data into
	 * the PC/P transmitter and set the PC/P BUSY signal.
	 */

	portman_write_command(pm, command | STROBE);

	/* Wait for strobe line to settle and echo back through hardware.
	 * Once it has echoed back, assume that the address and data lines
	 * have settled!
	 */

	while ((portman_read_status(pm) & ESTB) == 0)
		cpu_relax();

	/* Release strobe and immediately re-allow interrupts. */
	portman_write_command(pm, command);

	while ((portman_read_status(pm) & ESTB) == ESTB)
		cpu_relax();

	/* PC/P BUSY is now set.  We must wait until BUSY resets itself.
	 * We'll reenable ints while we're waiting.
	 */

	while ((portman_read_status(pm) & BUSY) == BUSY)
		cpu_relax();

	/* Data sent. */
}


/*
 *  Read MIDI byte from port
 *  Attempt to read input byte from specified hardware input port (0..).
 *  Return -1 if no data
 */
static int portman_read_midi(struct portman *pm, int port)
{
	unsigned char midi_data = 0;
	unsigned char cmdout;	/* Saved address+IE bit. */

	/* Make sure clocking edge is down before starting... */
	portman_write_data(pm, 0);	/* Make sure edge is down. */

	/* Set destination address to PCP. */
	cmdout = (port << 1) | INT_EN;	/* Address + IE + No Strobe. */
	portman_write_command(pm, cmdout);

	while ((portman_read_status(pm) & ESTB) == ESTB)
		cpu_relax();	/* Wait for strobe echo. */

	/* After the address lines settle, check multiplexed RxAvail signal.
	 * If data is available, read it.
	 */
	if ((portman_read_status(pm) & RXAVAIL) == 0)
		return -1;	/* No data. */

	/* Set the Strobe signal to enable the Rx clocking circuitry. */
	portman_write_command(pm, cmdout | STROBE);	/* Write address+IE+Strobe. */

	while ((portman_read_status(pm) & ESTB) == 0)
		cpu_relax(); /* Wait for strobe echo. */

	/* The first data bit (msb) is already sitting on the input line. */
	midi_data = (portman_read_status(pm) & 128);
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */

	/* Data bit 6. */
	portman_write_data(pm, 0);	/* Cause falling edge while data settles. */
	midi_data |= (portman_read_status(pm) >> 1) & 64;
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */

	/* Data bit 5. */
	portman_write_data(pm, 0);	/* Cause falling edge while data settles. */
	midi_data |= (portman_read_status(pm) >> 2) & 32;
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */

	/* Data bit 4. */
	portman_write_data(pm, 0);	/* Cause falling edge while data settles. */
	midi_data |= (portman_read_status(pm) >> 3) & 16;
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */

	/* Data bit 3. */
	portman_write_data(pm, 0);	/* Cause falling edge while data settles. */
	midi_data |= (portman_read_status(pm) >> 4) & 8;
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */

	/* Data bit 2. */
	portman_write_data(pm, 0);	/* Cause falling edge while data settles. */
	midi_data |= (portman_read_status(pm) >> 5) & 4;
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */

	/* Data bit 1. */
	portman_write_data(pm, 0);	/* Cause falling edge while data settles. */
	midi_data |= (portman_read_status(pm) >> 6) & 2;
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */

	/* Data bit 0. */
	portman_write_data(pm, 0);	/* Cause falling edge while data settles. */
	midi_data |= (portman_read_status(pm) >> 7) & 1;
	portman_write_data(pm, 1);	/* Cause rising edge, which shifts data. */
	portman_write_data(pm, 0);	/* Return data clock low. */


	/* De-assert Strobe and return data. */
	portman_write_command(pm, cmdout);	/* Output saved address+IE. */

	/* Wait for strobe echo. */
	while ((portman_read_status(pm) & ESTB) == ESTB)
		cpu_relax();

	return (midi_data & 255);	/* Shift back and return value. */
}

/*
 *  Checks if any input data on the given channel is available
 *  Checks RxAvail
 */
static int portman_data_avail(struct portman *pm, int channel)
{
	int command = INT_EN;
	switch (channel) {
	case 0:
		command |= RXDATA0;
		break;
	case 1:
		command |= RXDATA1;
		break;
	}
	/* Write hardware (assumme STROBE=0) */
	portman_write_command(pm, command);
	/* Check multiplexed RxAvail signal */
	if ((portman_read_status(pm) & RXAVAIL) == RXAVAIL)
		return 1;	/* Data available */

	/* No Data available */
	return 0;
}


/*
 *  Flushes any input
 */
static void portman_flush_input(struct portman *pm, unsigned char port)
{
	/* Local variable for counting things */
	unsigned int i = 0;
	unsigned char command = 0;

	switch (port) {
	case 0:
		command = RXDATA0;
		break;
	case 1:
		command = RXDATA1;
		break;
	default:
		snd_printk(KERN_WARNING
			   "portman_flush_input() Won't flush port %i\n",
			   port);
		return;
	}

	/* Set address for specified channel in port and allow to settle. */
	portman_write_command(pm, command);

	/* Assert the Strobe and wait for echo back. */
	portman_write_command(pm, command | STROBE);

	/* Wait for ESTB */
	while ((portman_read_status(pm) & ESTB) == 0)
		cpu_relax();

	/* Output clock cycles to the Rx circuitry. */
	portman_write_data(pm, 0);

	/* Flush 250 bits... */
	for (i = 0; i < 250; i++) {
		portman_write_data(pm, 1);
		portman_write_data(pm, 0);
	}

	/* Deassert the Strobe signal of the port and wait for it to settle. */
	portman_write_command(pm, command | INT_EN);

	/* Wait for settling */
	while ((portman_read_status(pm) & ESTB) == ESTB)
		cpu_relax();
}

static int portman_probe(struct parport *p)
{
	/* Initialize the parallel port data register.  Will set Rx clocks
	 * low in case we happen to be addressing the Rx ports at this time.
	 */
	/* 1 */
	parport_write_data(p, 0);

	/* Initialize the parallel port command register, thus initializing
	 * hardware handshake lines to midi box:
	 *
	 *                                  Strobe = 0
	 *                                  Interrupt Enable = 0
	 */
	/* 2 */
	parport_write_control(p, 0);

	/* Check if Portman PC/P 2x4 is out there. */
	/* 3 */
	parport_write_control(p, RXDATA0);	/* Write Strobe=0 to command reg. */

	/* Check for ESTB to be clear */
	/* 4 */
	if ((parport_read_status(p) & ESTB) == ESTB)
		return 1;	/* CODE 1 - Strobe Failure. */

	/* Set for RXDATA0 where no damage will be done. */
	/* 5 */
	parport_write_control(p, RXDATA0 + STROBE);	/* Write Strobe=1 to command reg. */

	/* 6 */
	if ((parport_read_status(p) & ESTB) != ESTB)
		return 1;	/* CODE 1 - Strobe Failure. */

	/* 7 */
	parport_write_control(p, 0);	/* Reset Strobe=0. */

	/* Check if Tx circuitry is functioning properly.  If initialized
	 * unit TxEmpty is false, send out char and see if if goes true.
	 */
	/* 8 */
	parport_write_control(p, TXDATA0);	/* Tx channel 0, strobe off. */

	/* If PCP channel's TxEmpty is set (TxEmpty is read through the PP
	 * Status Register), then go write data.  Else go back and wait.
	 */
	/* 9 */
	if ((parport_read_status(p) & TXEMPTY) == 0)
		return 2;

	/* Return OK status. */
	return 0;
}

static int portman_device_init(struct portman *pm)
{
	portman_flush_input(pm, 0);
	portman_flush_input(pm, 1);

	return 0;
}

/*********************************************************************
 * Rawmidi
 *********************************************************************/
static int snd_portman_midi_open(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static int snd_portman_midi_close(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static void snd_portman_midi_input_trigger(struct snd_rawmidi_substream *substream,
					   int up)
{
	struct portman *pm = substream->rmidi->private_data;
	unsigned long flags;

	spin_lock_irqsave(&pm->reg_lock, flags);
	if (up)
		pm->mode[substream->number] |= PORTMAN2X4_MODE_INPUT_TRIGGERED;
	else
		pm->mode[substream->number] &= ~PORTMAN2X4_MODE_INPUT_TRIGGERED;
	spin_unlock_irqrestore(&pm->reg_lock, flags);
}

static void snd_portman_midi_output_trigger(struct snd_rawmidi_substream *substream,
					    int up)
{
	struct portman *pm = substream->rmidi->private_data;
	unsigned long flags;
	unsigned char byte;

	spin_lock_irqsave(&pm->reg_lock, flags);
	if (up) {
		while ((snd_rawmidi_transmit(substream, &byte, 1) == 1))
			portman_write_midi(pm, substream->number, byte);
	}
	spin_unlock_irqrestore(&pm->reg_lock, flags);
}

static struct snd_rawmidi_ops snd_portman_midi_output = {
	.open =		snd_portman_midi_open,
	.close =	snd_portman_midi_close,
	.trigger =	snd_portman_midi_output_trigger,
};

static struct snd_rawmidi_ops snd_portman_midi_input = {
	.open =		snd_portman_midi_open,
	.close =	snd_portman_midi_close,
	.trigger =	snd_portman_midi_input_trigger,
};

/* Create and initialize the rawmidi component */
static int __devinit snd_portman_rawmidi_create(struct snd_card *card)
{
	struct portman *pm = card->private_data;
	struct snd_rawmidi *rmidi;
	struct snd_rawmidi_substream *substream;
	int err;

	err = snd_rawmidi_new(card, CARD_NAME, 0,
			      PORTMAN_NUM_OUTPUT_PORTS,
			      PORTMAN_NUM_INPUT_PORTS,
			      &rmidi);
	if (err < 0)
		return err;

	rmidi->private_data = pm;
	strcpy(rmidi->name, CARD_NAME);
	rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
		            SNDRV_RAWMIDI_INFO_INPUT |
                            SNDRV_RAWMIDI_INFO_DUPLEX;

	pm->rmidi = rmidi;

	/* register rawmidi ops */
	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
			    &snd_portman_midi_output);
	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
			    &snd_portman_midi_input);

	/* name substreams */
	/* output */
	list_for_each_entry(substream,
			    &rmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT].substreams,
			    list) {
		sprintf(substream->name,
			"Portman2x4 %d", substream->number+1);
	}
	/* input */
	list_for_each_entry(substream,
			    &rmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT].substreams,
			    list) {
		pm->midi_input[substream->number] = substream;
		sprintf(substream->name,
			"Portman2x4 %d", substream->number+1);
	}

	return err;
}

/*********************************************************************
 * parport stuff
 *********************************************************************/
static void snd_portman_interrupt(void *userdata)
{
	unsigned char midivalue = 0;
	struct portman *pm = ((struct snd_card*)userdata)->private_data;

	spin_lock(&pm->reg_lock);

	/* While any input data is waiting */
	while ((portman_read_status(pm) & INT_REQ) == INT_REQ) {
		/* If data available on channel 0,
		   read it and stuff it into the queue. */
		if (portman_data_avail(pm, 0)) {
			/* Read Midi */
			midivalue = portman_read_midi(pm, 0);
			/* put midi into queue... */
			if (pm->mode[0] & PORTMAN2X4_MODE_INPUT_TRIGGERED)
				snd_rawmidi_receive(pm->midi_input[0],
						    &midivalue, 1);

		}
		/* If data available on channel 1,
		   read it and stuff it into the queue. */
		if (portman_data_avail(pm, 1)) {
			/* Read Midi */
			midivalue = portman_read_midi(pm, 1);
			/* put midi into queue... */
			if (pm->mode[1] & PORTMAN2X4_MODE_INPUT_TRIGGERED)
				snd_rawmidi_receive(pm->midi_input[1],
						    &midivalue, 1);
		}

	}

	spin_unlock(&pm->reg_lock);
}

static int __devinit snd_portman_probe_port(struct parport *p)
{
	struct pardevice *pardev;
	int res;

	pardev = parport_register_device(p, DRIVER_NAME,
					 NULL, NULL, NULL,
					 0, NULL);
	if (!pardev)
		return -EIO;

	if (parport_claim(pardev)) {
		parport_unregister_device(pardev);
		return -EIO;
	}

	res = portman_probe(p);

	parport_release(pardev);
	parport_unregister_device(pardev);

	return res ? -EIO : 0;
}

static void __devinit snd_portman_attach(struct parport *p)
{
	struct platform_device *device;

	device = platform_device_alloc(PLATFORM_DRIVER, device_count);
	if (!device)
		return;

	/* Temporary assignment to forward the parport */
	platform_set_drvdata(device, p);

	if (platform_device_add(device) < 0) {
		platform_device_put(device);
		return;
	}

	/* Since we dont get the return value of probe
	 * We need to check if device probing succeeded or not */
	if (!platform_get_drvdata(device)) {
		platform_device_unregister(device);
		return;
	}

	/* register device in global table */
	platform_devices[device_count] = device;
	device_count++;
}

static void snd_portman_detach(struct parport *p)
{
	/* nothing to do here */
}

static struct parport_driver portman_parport_driver = {
	.name   = "portman2x4",
	.attach = snd_portman_attach,
	.detach = snd_portman_detach
};

/*********************************************************************
 * platform stuff
 *********************************************************************/
static void snd_portman_card_private_free(struct snd_card *card)
{
	struct portman *pm = card->private_data;
	struct pardevice *pardev = pm->pardev;

	if (pardev) {
		if (pm->pardev_claimed)
			parport_release(pardev);
		parport_unregister_device(pardev);
	}

	portman_free(pm);
}

static int __devinit snd_portman_probe(struct platform_device *pdev)
{
	struct pardevice *pardev;
	struct parport *p;
	int dev = pdev->id;
	struct snd_card *card = NULL;
	struct portman *pm = NULL;
	int err;

	p = platform_get_drvdata(pdev);
	platform_set_drvdata(pdev, NULL);

	if (dev >= SNDRV_CARDS)
		return -ENODEV;
	if (!enable[dev])
		return -ENOENT;

	if ((err = snd_portman_probe_port(p)) < 0)
		return err;

	err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
	if (err < 0) {
		snd_printd("Cannot create card\n");
		return err;
	}
	strcpy(card->driver, DRIVER_NAME);
	strcpy(card->shortname, CARD_NAME);
	sprintf(card->longname,  "%s at 0x%lx, irq %i",
		card->shortname, p->base, p->irq);

	pardev = parport_register_device(p,                     /* port */
					 DRIVER_NAME,           /* name */
					 NULL,                  /* preempt */
					 NULL,                  /* wakeup */
					 snd_portman_interrupt, /* ISR */
					 PARPORT_DEV_EXCL,      /* flags */
					 (void *)card);         /* private */
	if (pardev == NULL) {
		snd_printd("Cannot register pardevice\n");
		err = -EIO;
		goto __err;
	}

	if ((err = portman_create(card, pardev, &pm)) < 0) {
		snd_printd("Cannot create main component\n");
		parport_unregister_device(pardev);
		goto __err;
	}
	card->private_data = pm;
	card->private_free = snd_portman_card_private_free;

	if ((err = snd_portman_rawmidi_create(card)) < 0) {
		snd_printd("Creating Rawmidi component failed\n");
		goto __err;
	}

	/* claim parport */
	if (parport_claim(pardev)) {
		snd_printd("Cannot claim parport 0x%lx\n", pardev->port->base);
		err = -EIO;
		goto __err;
	}
	pm->pardev_claimed = 1;

	/* init device */
	if ((err = portman_device_init(pm)) < 0)
		goto __err;

	platform_set_drvdata(pdev, card);

	snd_card_set_dev(card, &pdev->dev);

	/* At this point card will be usable */
	if ((err = snd_card_register(card)) < 0) {
		snd_printd("Cannot register card\n");
		goto __err;
	}

	snd_printk(KERN_INFO "Portman 2x4 on 0x%lx\n", p->base);
	return 0;

__err:
	snd_card_free(card);
	return err;
}

static int __devexit snd_portman_remove(struct platform_device *pdev)
{
	struct snd_card *card = platform_get_drvdata(pdev);

	if (card)
		snd_card_free(card);

	return 0;
}


static struct platform_driver snd_portman_driver = {
	.probe  = snd_portman_probe,
	.remove = __devexit_p(snd_portman_remove),
	.driver = {
		.name = PLATFORM_DRIVER
	}
};

/*********************************************************************
 * module init stuff
 *********************************************************************/
static void snd_portman_unregister_all(void)
{
	int i;

	for (i = 0; i < SNDRV_CARDS; ++i) {
		if (platform_devices[i]) {
			platform_device_unregister(platform_devices[i]);
			platform_devices[i] = NULL;
		}
	}
	platform_driver_unregister(&snd_portman_driver);
	parport_unregister_driver(&portman_parport_driver);
}

static int __init snd_portman_module_init(void)
{
	int err;

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

	if (parport_register_driver(&portman_parport_driver) != 0) {
		platform_driver_unregister(&snd_portman_driver);
		return -EIO;
	}

	if (device_count == 0) {
		snd_portman_unregister_all();
		return -ENODEV;
	}

	return 0;
}

static void __exit snd_portman_module_exit(void)
{
	snd_portman_unregister_all();
}

module_init(snd_portman_module_init);
module_exit(snd_portman_module_exit);