[linux-block.git] / drivers / spi / spi_butterfly.c

/*
 * spi_butterfly.c - parport-to-butterfly adapter
 *
 * Copyright (C) 2005 David Brownell
 *
 * 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.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/parport.h>

#include <linux/sched.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/spi/flash.h>

#include <linux/mtd/partitions.h>


/*
 * This uses SPI to talk with an "AVR Butterfly", which is a $US20 card
 * with a battery powered AVR microcontroller and lots of goodies.  You
 * can use GCC to develop firmware for this.
 *
 * See Documentation/spi/butterfly for information about how to build
 * and use this custom parallel port cable.
 */


/* DATA output bits (pins 2..9 == D0..D7) */
#define	butterfly_nreset (1 << 1)		/* pin 3 */

#define	spi_sck_bit	(1 << 0)		/* pin 2 */
#define	spi_mosi_bit	(1 << 7)		/* pin 9 */

#define	vcc_bits	((1 << 6) | (1 << 5))	/* pins 7, 8 */

/* STATUS input bits */
#define	spi_miso_bit	PARPORT_STATUS_BUSY	/* pin 11 */

/* CONTROL output bits */
#define	spi_cs_bit	PARPORT_CONTROL_SELECT	/* pin 17 */


static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
{
	return spi->controller_data;
}


struct butterfly {
	/* REVISIT ... for now, this must be first */
	struct spi_bitbang	bitbang;

	struct parport		*port;
	struct pardevice	*pd;

	u8			lastbyte;

	struct spi_device	*dataflash;
	struct spi_device	*butterfly;
	struct spi_board_info	info[2];

};

/*----------------------------------------------------------------------*/

static inline void
setsck(struct spi_device *spi, int is_on)
{
	struct butterfly	*pp = spidev_to_pp(spi);
	u8			bit, byte = pp->lastbyte;

	bit = spi_sck_bit;

	if (is_on)
		byte |= bit;
	else
		byte &= ~bit;
	parport_write_data(pp->port, byte);
	pp->lastbyte = byte;
}

static inline void
setmosi(struct spi_device *spi, int is_on)
{
	struct butterfly	*pp = spidev_to_pp(spi);
	u8			bit, byte = pp->lastbyte;

	bit = spi_mosi_bit;

	if (is_on)
		byte |= bit;
	else
		byte &= ~bit;
	parport_write_data(pp->port, byte);
	pp->lastbyte = byte;
}

static inline int getmiso(struct spi_device *spi)
{
	struct butterfly	*pp = spidev_to_pp(spi);
	int			value;
	u8			bit;

	bit = spi_miso_bit;

	/* only STATUS_BUSY is NOT negated */
	value = !(parport_read_status(pp->port) & bit);
	return (bit == PARPORT_STATUS_BUSY) ? value : !value;
}

static void butterfly_chipselect(struct spi_device *spi, int value)
{
	struct butterfly	*pp = spidev_to_pp(spi);

	/* set default clock polarity */
	if (value != BITBANG_CS_INACTIVE)
		setsck(spi, spi->mode & SPI_CPOL);

	/* here, value == "activate or not";
	 * most PARPORT_CONTROL_* bits are negated, so we must
	 * morph it to value == "bit value to write in control register"
	 */
	if (spi_cs_bit == PARPORT_CONTROL_INIT)
		value = !value;

	parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
}


/* we only needed to implement one mode here, and choose SPI_MODE_0 */

#define	spidelay(X)	do{}while(0)
//#define	spidelay	ndelay

#define	EXPAND_BITBANG_TXRX
#include <linux/spi/spi_bitbang.h>

static u32
butterfly_txrx_word_mode0(struct spi_device *spi,
		unsigned nsecs,
		u32 word, u8 bits)
{
	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
}

/*----------------------------------------------------------------------*/

/* override default partitioning with cmdlinepart */
static struct mtd_partition partitions[] = { {
	/* JFFS2 wants partitions of 4*N blocks for this device,
	 * so sectors 0 and 1 can't be partitions by themselves.
	 */

	/* sector 0 = 8 pages * 264 bytes/page (1 block)
	 * sector 1 = 248 pages * 264 bytes/page
	 */
	.name		= "bookkeeping",	// 66 KB
	.offset		= 0,
	.size		= (8 + 248) * 264,
//	.mask_flags	= MTD_WRITEABLE,
}, {
	/* sector 2 = 256 pages * 264 bytes/page
	 * sectors 3-5 = 512 pages * 264 bytes/page
	 */
	.name		= "filesystem",		// 462 KB
	.offset		= MTDPART_OFS_APPEND,
	.size		= MTDPART_SIZ_FULL,
} };

static struct flash_platform_data flash = {
	.name		= "butterflash",
	.parts		= partitions,
	.nr_parts	= ARRAY_SIZE(partitions),
};


/* REVISIT remove this ugly global and its "only one" limitation */
static struct butterfly *butterfly;

static void butterfly_attach(struct parport *p)
{
	struct pardevice	*pd;
	int			status;
	struct butterfly	*pp;
	struct spi_master	*master;
	struct device		*dev = p->physport->dev;

	if (butterfly || !dev)
		return;

	/* REVISIT:  this just _assumes_ a butterfly is there ... no probe,
	 * and no way to be selective about what it binds to.
	 */

	master = spi_alloc_master(dev, sizeof *pp);
	if (!master) {
		status = -ENOMEM;
		goto done;
	}
	pp = spi_master_get_devdata(master);

	/*
	 * SPI and bitbang hookup
	 *
	 * use default setup(), cleanup(), and transfer() methods; and
	 * only bother implementing mode 0.  Start it later.
	 */
	master->bus_num = 42;
	master->num_chipselect = 2;

	pp->bitbang.master = spi_master_get(master);
	pp->bitbang.chipselect = butterfly_chipselect;
	pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;

	/*
	 * parport hookup
	 */
	pp->port = p;
	pd = parport_register_device(p, "spi_butterfly",
			NULL, NULL, NULL,
			0 /* FLAGS */, pp);
	if (!pd) {
		status = -ENOMEM;
		goto clean0;
	}
	pp->pd = pd;

	status = parport_claim(pd);
	if (status < 0)
		goto clean1;

	/*
	 * Butterfly reset, powerup, run firmware
	 */
	pr_debug("%s: powerup/reset Butterfly\n", p->name);

	/* nCS for dataflash (this bit is inverted on output) */
	parport_frob_control(pp->port, spi_cs_bit, 0);

	/* stabilize power with chip in reset (nRESET), and
	 * spi_sck_bit clear (CPOL=0)
	 */
	pp->lastbyte |= vcc_bits;
	parport_write_data(pp->port, pp->lastbyte);
	msleep(5);

	/* take it out of reset; assume long reset delay */
	pp->lastbyte |= butterfly_nreset;
	parport_write_data(pp->port, pp->lastbyte);
	msleep(100);


	/*
	 * Start SPI ... for now, hide that we're two physical busses.
	 */
	status = spi_bitbang_start(&pp->bitbang);
	if (status < 0)
		goto clean2;

	/* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR
	 * (firmware resets at45, acts as spi slave) or neither (we ignore
	 * both, AVR uses AT45).  Here we expect firmware for the first option.
	 */

	pp->info[0].max_speed_hz = 15 * 1000 * 1000;
	strcpy(pp->info[0].modalias, "mtd_dataflash");
	pp->info[0].platform_data = &flash;
	pp->info[0].chip_select = 1;
	pp->info[0].controller_data = pp;
	pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]);
	if (pp->dataflash)
		pr_debug("%s: dataflash at %s\n", p->name,
				dev_name(&pp->dataflash->dev));

	// dev_info(_what?_, ...)
	pr_info("%s: AVR Butterfly\n", p->name);
	butterfly = pp;
	return;

clean2:
	/* turn off VCC */
	parport_write_data(pp->port, 0);

	parport_release(pp->pd);
clean1:
	parport_unregister_device(pd);
clean0:
	(void) spi_master_put(pp->bitbang.master);
done:
	pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
}

static void butterfly_detach(struct parport *p)
{
	struct butterfly	*pp;
	int			status;

	/* FIXME this global is ugly ... but, how to quickly get from
	 * the parport to the "struct butterfly" associated with it?
	 * "old school" driver-internal device lists?
	 */
	if (!butterfly || butterfly->port != p)
		return;
	pp = butterfly;
	butterfly = NULL;

	/* stop() unregisters child devices too */
	status = spi_bitbang_stop(&pp->bitbang);

	/* turn off VCC */
	parport_write_data(pp->port, 0);
	msleep(10);

	parport_release(pp->pd);
	parport_unregister_device(pp->pd);

	(void) spi_master_put(pp->bitbang.master);
}

static struct parport_driver butterfly_driver = {
	.name =		"spi_butterfly",
	.attach =	butterfly_attach,
	.detach =	butterfly_detach,
};


static int __init butterfly_init(void)
{
	return parport_register_driver(&butterfly_driver);
}
device_initcall(butterfly_init);

static void __exit butterfly_exit(void)
{
	parport_unregister_driver(&butterfly_driver);
}
module_exit(butterfly_exit);

MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly");
MODULE_LICENSE("GPL");
Commit	Line	Data
2e10c84b DB	1	/*
	2	* spi_butterfly.c - parport-to-butterfly adapter
	3	*
	4	* Copyright (C) 2005 David Brownell
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	19	*/
2e10c84b DB	20	#include <linux/kernel.h>
	21	#include <linux/init.h>
	22	#include <linux/delay.h>
da675296	23	#include <linux/device.h>
2e10c84b DB	24	#include <linux/parport.h>
2e10c84b DB	25
914e2637	26	#include <linux/sched.h>
2e10c84b DB	27	#include <linux/spi/spi.h>
	28	#include <linux/spi/spi_bitbang.h>
	29	#include <linux/spi/flash.h>
	30
	31	#include <linux/mtd/partitions.h>
	32
	33
	34	/*
	35	* This uses SPI to talk with an "AVR Butterfly", which is a $US20 card
	36	* with a battery powered AVR microcontroller and lots of goodies. You
	37	* can use GCC to develop firmware for this.
	38	*
	39	* See Documentation/spi/butterfly for information about how to build
	40	* and use this custom parallel port cable.
	41	*/
	42
2e10c84b DB	43
	44	/* DATA output bits (pins 2..9 == D0..D7) */
	45	#define butterfly_nreset (1 << 1) /* pin 3 */
	46
	47	#define spi_sck_bit (1 << 0) /* pin 2 */
	48	#define spi_mosi_bit (1 << 7) /* pin 9 */
	49
2e10c84b DB	50	#define vcc_bits ((1 << 6) \| (1 << 5)) /* pins 7, 8 */
	51
	52	/* STATUS input bits */
	53	#define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */
	54
2e10c84b DB	55	/* CONTROL output bits */
2e10c84b DB	56	#define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
2e10c84b DB	57
	58
	59
	60	static inline struct butterfly spidev_to_pp(struct spi_device spi)
	61	{
	62	return spi->controller_data;
	63	}
	64
2e10c84b DB	65
	66	struct butterfly {
	67	/* REVISIT ... for now, this must be first */
	68	struct spi_bitbang bitbang;
	69
	70	struct parport *port;
	71	struct pardevice *pd;
	72
	73	u8 lastbyte;
	74
	75	struct spi_device *dataflash;
	76	struct spi_device *butterfly;
	77	struct spi_board_info info[2];
	78
	79	};
	80
	81	/----------------------------------------------------------------------/
	82
2e10c84b DB	83	static inline void
	84	setsck(struct spi_device *spi, int is_on)
	85	{
	86	struct butterfly *pp = spidev_to_pp(spi);
	87	u8 bit, byte = pp->lastbyte;
	88
735ce95e	89	bit = spi_sck_bit;
2e10c84b DB	90
	91	if (is_on)
	92	byte \|= bit;
	93	else
	94	byte &= ~bit;
	95	parport_write_data(pp->port, byte);
	96	pp->lastbyte = byte;
	97	}
	98
	99	static inline void
	100	setmosi(struct spi_device *spi, int is_on)
	101	{
	102	struct butterfly *pp = spidev_to_pp(spi);
	103	u8 bit, byte = pp->lastbyte;
	104
735ce95e	105	bit = spi_mosi_bit;
2e10c84b DB	106
	107	if (is_on)
	108	byte \|= bit;
	109	else
	110	byte &= ~bit;
	111	parport_write_data(pp->port, byte);
	112	pp->lastbyte = byte;
	113	}
	114
	115	static inline int getmiso(struct spi_device *spi)
	116	{
	117	struct butterfly *pp = spidev_to_pp(spi);
	118	int value;
	119	u8 bit;
	120
735ce95e	121	bit = spi_miso_bit;
2e10c84b DB	122
	123	/* only STATUS_BUSY is NOT negated */
	124	value = !(parport_read_status(pp->port) & bit);
	125	return (bit == PARPORT_STATUS_BUSY) ? value : !value;
	126	}
	127
	128	static void butterfly_chipselect(struct spi_device *spi, int value)
	129	{
	130	struct butterfly *pp = spidev_to_pp(spi);
	131
	132	/* set default clock polarity */
9c1da3cb	133	if (value != BITBANG_CS_INACTIVE)
2e10c84b DB	134	setsck(spi, spi->mode & SPI_CPOL);
2e10c84b DB	135
9c1da3cb DB	136	/* here, value == "activate or not";
	137	* most PARPORT_CONTROL_* bits are negated, so we must
	138	* morph it to value == "bit value to write in control register"
	139	*/
2e10c84b DB	140	if (spi_cs_bit == PARPORT_CONTROL_INIT)
	141	value = !value;
	142
2e10c84b DB	143	parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
	144	}
	145
	146
	147	/* we only needed to implement one mode here, and choose SPI_MODE_0 */
	148
	149	#define spidelay(X) do{}while(0)
	150	//#define spidelay ndelay
	151
	152	#define EXPAND_BITBANG_TXRX
	153	#include <linux/spi/spi_bitbang.h>
	154
	155	static u32
	156	butterfly_txrx_word_mode0(struct spi_device *spi,
	157	unsigned nsecs,
	158	u32 word, u8 bits)
	159	{
	160	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
	161	}
	162
	163	/----------------------------------------------------------------------/
	164
	165	/* override default partitioning with cmdlinepart */
	166	static struct mtd_partition partitions[] = { {
9c1da3cb DB	167	/* JFFS2 wants partitions of 4*N blocks for this device,
	168	* so sectors 0 and 1 can't be partitions by themselves.
	169	*/
2e10c84b DB	170
	171	/* sector 0 = 8 pages * 264 bytes/page (1 block)
	172	* sector 1 = 248 pages * 264 bytes/page
	173	*/
	174	.name = "bookkeeping", // 66 KB
	175	.offset = 0,
	176	.size = (8 + 248) * 264,
	177	// .mask_flags = MTD_WRITEABLE,
	178	}, {
	179	/* sector 2 = 256 pages * 264 bytes/page
	180	* sectors 3-5 = 512 pages * 264 bytes/page
	181	*/
	182	.name = "filesystem", // 462 KB
	183	.offset = MTDPART_OFS_APPEND,
	184	.size = MTDPART_SIZ_FULL,
	185	} };
	186
	187	static struct flash_platform_data flash = {
	188	.name = "butterflash",
	189	.parts = partitions,
	190	.nr_parts = ARRAY_SIZE(partitions),
	191	};
	192
	193
	194	/* REVISIT remove this ugly global and its "only one" limitation */
	195	static struct butterfly *butterfly;
	196
	197	static void butterfly_attach(struct parport *p)
	198	{
	199	struct pardevice *pd;
	200	int status;
	201	struct butterfly *pp;
	202	struct spi_master *master;
da675296	203	struct device *dev = p->physport->dev;
2e10c84b	204
da675296	205	if (butterfly \|\| !dev)
2e10c84b DB	206	return;
	207
	208	/* REVISIT: this just _assumes_ a butterfly is there ... no probe,
	209	* and no way to be selective about what it binds to.
	210	*/
	211
da675296	212	master = spi_alloc_master(dev, sizeof *pp);
2e10c84b DB	213	if (!master) {
	214	status = -ENOMEM;
	215	goto done;
	216	}
	217	pp = spi_master_get_devdata(master);
	218
	219	/*
	220	* SPI and bitbang hookup
	221	*
	222	* use default setup(), cleanup(), and transfer() methods; and
	223	* only bother implementing mode 0. Start it later.
	224	*/
	225	master->bus_num = 42;
	226	master->num_chipselect = 2;
	227
	228	pp->bitbang.master = spi_master_get(master);
	229	pp->bitbang.chipselect = butterfly_chipselect;
	230	pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;
	231
	232	/*
	233	* parport hookup
	234	*/
	235	pp->port = p;
	236	pd = parport_register_device(p, "spi_butterfly",
	237	NULL, NULL, NULL,
	238	0 /* FLAGS */, pp);
	239	if (!pd) {
	240	status = -ENOMEM;
	241	goto clean0;
	242	}
	243	pp->pd = pd;
	244
	245	status = parport_claim(pd);
	246	if (status < 0)
	247	goto clean1;
	248
	249	/*
	250	* Butterfly reset, powerup, run firmware
	251	*/
	252	pr_debug("%s: powerup/reset Butterfly\n", p->name);
	253
	254	/* nCS for dataflash (this bit is inverted on output) */
	255	parport_frob_control(pp->port, spi_cs_bit, 0);
	256
	257	/* stabilize power with chip in reset (nRESET), and
735ce95e	258	* spi_sck_bit clear (CPOL=0)
2e10c84b DB	259	*/
	260	pp->lastbyte \|= vcc_bits;
	261	parport_write_data(pp->port, pp->lastbyte);
	262	msleep(5);
	263
	264	/* take it out of reset; assume long reset delay */
	265	pp->lastbyte \|= butterfly_nreset;
	266	parport_write_data(pp->port, pp->lastbyte);
	267	msleep(100);
	268
	269
	270	/*
	271	* Start SPI ... for now, hide that we're two physical busses.
	272	*/
	273	status = spi_bitbang_start(&pp->bitbang);
	274	if (status < 0)
	275	goto clean2;
	276
9c1da3cb DB	277	/* Bus 1 lets us talk to at45db041b (firmware disables AVR SPI), AVR
	278	* (firmware resets at45, acts as spi slave) or neither (we ignore
	279	* both, AVR uses AT45). Here we expect firmware for the first option.
2e10c84b	280	*/
1fc7547d	281
2e10c84b DB	282	pp->info[0].max_speed_hz = 15 * 1000 * 1000;
	283	strcpy(pp->info[0].modalias, "mtd_dataflash");
	284	pp->info[0].platform_data = &flash;
	285	pp->info[0].chip_select = 1;
	286	pp->info[0].controller_data = pp;
	287	pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]);
	288	if (pp->dataflash)
	289	pr_debug("%s: dataflash at %s\n", p->name,
35f74fca	290	dev_name(&pp->dataflash->dev));
2e10c84b	291
2e10c84b DB	292	// dev_info(_what?_, ...)
	293	pr_info("%s: AVR Butterfly\n", p->name);
	294	butterfly = pp;
	295	return;
	296
	297	clean2:
	298	/* turn off VCC */
	299	parport_write_data(pp->port, 0);
	300
	301	parport_release(pp->pd);
	302	clean1:
	303	parport_unregister_device(pd);
	304	clean0:
	305	(void) spi_master_put(pp->bitbang.master);
	306	done:
2e10c84b DB	307	pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
	308	}
	309
	310	static void butterfly_detach(struct parport *p)
	311	{
	312	struct butterfly *pp;
2e10c84b DB	313	int status;
	314
	315	/* FIXME this global is ugly ... but, how to quickly get from
	316	* the parport to the "struct butterfly" associated with it?
	317	* "old school" driver-internal device lists?
	318	*/
	319	if (!butterfly \|\| butterfly->port != p)
	320	return;
	321	pp = butterfly;
	322	butterfly = NULL;
	323
9c1da3cb	324	/* stop() unregisters child devices too */
2e10c84b DB	325	status = spi_bitbang_stop(&pp->bitbang);
	326
	327	/* turn off VCC */
	328	parport_write_data(pp->port, 0);
	329	msleep(10);
	330
	331	parport_release(pp->pd);
	332	parport_unregister_device(pp->pd);
	333
2e10c84b	334	(void) spi_master_put(pp->bitbang.master);
2e10c84b DB	335	}
	336
	337	static struct parport_driver butterfly_driver = {
	338	.name = "spi_butterfly",
	339	.attach = butterfly_attach,
	340	.detach = butterfly_detach,
	341	};
	342
	343
	344	static int __init butterfly_init(void)
	345	{
	346	return parport_register_driver(&butterfly_driver);
	347	}
	348	device_initcall(butterfly_init);
	349
	350	static void __exit butterfly_exit(void)
	351	{
	352	parport_unregister_driver(&butterfly_driver);
	353	}
	354	module_exit(butterfly_exit);
	355
9c1da3cb	356	MODULE_DESCRIPTION("Parport Adapter driver for AVR Butterfly");
2e10c84b	357	MODULE_LICENSE("GPL");