[linux-2.6-block.git] / drivers / spi / spi-lm70llp.c

/*
 * Driver for LM70EVAL-LLP board for the LM70 sensor
 *
 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.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.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/parport.h>
#include <linux/sysfs.h>
#include <linux/workqueue.h>


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


/*
 * The LM70 communicates with a host processor using a 3-wire variant of
 * the SPI/Microwire bus interface. This driver specifically supports an
 * NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel
 * port to bitbang an SPI-parport bridge.  Accordingly, this is an SPI
 * master controller driver.  The hwmon/lm70 driver is a "SPI protocol
 * driver", layered on top of this one and usable without the lm70llp.
 *
 * Datasheet and Schematic:
 * The LM70 is a temperature sensor chip from National Semiconductor; its
 * datasheet is available at http://www.national.com/pf/LM/LM70.html
 * The schematic for this particular board (the LM70EVAL-LLP) is
 * available (on page 4) here:
 *  http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf
 *
 * Also see Documentation/spi/spi-lm70llp.  The SPI<->parport code here is
 * (heavily) based on spi-butterfly by David Brownell.
 *
 * The LM70 LLP connects to the PC parallel port in the following manner:
 *
 *   Parallel                 LM70 LLP
 *     Port      Direction   JP2 Header
 *  -----------  ---------  ------------
 *      D0    2      -         -
 *      D1    3     -->      V+   5
 *      D2    4     -->      V+   5
 *      D3    5     -->      V+   5
 *      D4    6     -->      V+   5
 *      D5    7     -->      nCS  8
 *      D6    8     -->      SCLK 3
 *      D7    9     -->      SI/O 5
 *     GND   25      -       GND  7
 *    Select 13     <--      SI/O 1
 *
 * Note that parport pin 13 actually gets inverted by the transistor
 * arrangement which lets either the parport or the LM70 drive the
 * SI/SO signal (see the schematic for details).
 */

#define DRVNAME		"spi-lm70llp"

#define lm70_INIT	0xBE
#define SIO		0x10
#define nCS		0x20
#define SCLK		0x40

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

struct spi_lm70llp {
	struct spi_bitbang	bitbang;
	struct parport		*port;
	struct pardevice	*pd;
	struct spi_device	*spidev_lm70;
	struct spi_board_info	info;
	//struct device		*dev;
};

/* REVISIT : ugly global ; provides "exclusive open" facility */
static struct spi_lm70llp *lm70llp;


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

static inline struct spi_lm70llp *spidev_to_pp(struct spi_device *spi)
{
	return spi->controller_data;
}

/*---------------------- LM70 LLP eval board-specific inlines follow */

/* NOTE:  we don't actually need to reread the output values, since they'll
 * still be what we wrote before.  Plus, going through parport builds in
 * a ~1ms/operation delay; these SPI transfers could easily be faster.
 */

static inline void deassertCS(struct spi_lm70llp *pp)
{
	u8 data = parport_read_data(pp->port);

	data &= ~0x80;		/* pull D7/SI-out low while de-asserted */
	parport_write_data(pp->port, data | nCS);
}

static inline void assertCS(struct spi_lm70llp *pp)
{
	u8 data = parport_read_data(pp->port);

	data |= 0x80;		/* pull D7/SI-out high so lm70 drives SO-in */
	parport_write_data(pp->port, data & ~nCS);
}

static inline void clkHigh(struct spi_lm70llp *pp)
{
	u8 data = parport_read_data(pp->port);
	parport_write_data(pp->port, data | SCLK);
}

static inline void clkLow(struct spi_lm70llp *pp)
{
	u8 data = parport_read_data(pp->port);
	parport_write_data(pp->port, data & ~SCLK);
}

/*------------------------- SPI-LM70-specific inlines ----------------------*/

static inline void spidelay(unsigned d)
{
	udelay(d);
}

static inline void setsck(struct spi_device *s, int is_on)
{
	struct spi_lm70llp *pp = spidev_to_pp(s);

	if (is_on)
		clkHigh(pp);
	else
		clkLow(pp);
}

static inline void setmosi(struct spi_device *s, int is_on)
{
	/* FIXME update D7 ... this way we can put the chip
	 * into shutdown mode and read the manufacturer ID,
	 * but we can't put it back into operational mode.
	 */
}

/*
 * getmiso:
 * Why do we return 0 when the SIO line is high and vice-versa?
 * The fact is, the lm70 eval board from NS (which this driver drives),
 * is wired in just such a way : when the lm70's SIO goes high, a transistor
 * switches it to low reflecting this on the parport (pin 13), and vice-versa.
 */
static inline int getmiso(struct spi_device *s)
{
	struct spi_lm70llp *pp = spidev_to_pp(s);
	return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1 );
}
/*--------------------------------------------------------------------*/

#include "spi-bitbang-txrx.h"

static void lm70_chipselect(struct spi_device *spi, int value)
{
	struct spi_lm70llp *pp = spidev_to_pp(spi);

	if (value)
		assertCS(pp);
	else
		deassertCS(pp);
}

/*
 * Our actual bitbanger routine.
 */
static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
{
	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
}

static void spi_lm70llp_attach(struct parport *p)
{
	struct pardevice	*pd;
	struct spi_lm70llp	*pp;
	struct spi_master	*master;
	int			status;

	if (lm70llp) {
		printk(KERN_WARNING
			"%s: spi_lm70llp instance already loaded. Aborting.\n",
			DRVNAME);
		return;
	}

	/* TODO:  this just _assumes_ a lm70 is there ... no probe;
	 * the lm70 driver could verify it, reading the manf ID.
	 */

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

	/*
	 * SPI and bitbang hookup.
	 */
	pp->bitbang.master = master;
	pp->bitbang.chipselect = lm70_chipselect;
	pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx;
	pp->bitbang.flags = SPI_3WIRE;

	/*
	 * Parport hookup
	 */
	pp->port = p;
	pd = parport_register_device(p, DRVNAME,
			NULL, NULL, NULL,
			PARPORT_FLAG_EXCL, pp);
	if (!pd) {
		status = -ENOMEM;
		goto out_free_master;
	}
	pp->pd = pd;

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

	/*
	 * Start SPI ...
	 */
	status = spi_bitbang_start(&pp->bitbang);
	if (status < 0) {
		printk(KERN_WARNING
			"%s: spi_bitbang_start failed with status %d\n",
			DRVNAME, status);
		goto out_off_and_release;
	}

	/*
	 * The modalias name MUST match the device_driver name
	 * for the bus glue code to match and subsequently bind them.
	 * We are binding to the generic drivers/hwmon/lm70.c device
	 * driver.
	 */
	strcpy(pp->info.modalias, "lm70");
	pp->info.max_speed_hz = 6 * 1000 * 1000;
	pp->info.chip_select = 0;
	pp->info.mode = SPI_3WIRE | SPI_MODE_0;

	/* power up the chip, and let the LM70 control SI/SO */
	parport_write_data(pp->port, lm70_INIT);

	/* Enable access to our primary data structure via
	 * the board info's (void *)controller_data.
	 */
	pp->info.controller_data = pp;
	pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info);
	if (pp->spidev_lm70)
		dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n",
				dev_name(&pp->spidev_lm70->dev));
	else {
		printk(KERN_WARNING "%s: spi_new_device failed\n", DRVNAME);
		status = -ENODEV;
		goto out_bitbang_stop;
	}
	pp->spidev_lm70->bits_per_word = 8;

	lm70llp = pp;
	return;

out_bitbang_stop:
	spi_bitbang_stop(&pp->bitbang);
out_off_and_release:
	/* power down */
	parport_write_data(pp->port, 0);
	mdelay(10);
	parport_release(pp->pd);
out_parport_unreg:
	parport_unregister_device(pd);
out_free_master:
	(void) spi_master_put(master);
out_fail:
	pr_info("%s: spi_lm70llp probe fail, status %d\n", DRVNAME, status);
}

static void spi_lm70llp_detach(struct parport *p)
{
	struct spi_lm70llp		*pp;

	if (!lm70llp || lm70llp->port != p)
		return;

	pp = lm70llp;
	spi_bitbang_stop(&pp->bitbang);

	/* power down */
	parport_write_data(pp->port, 0);

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

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

	lm70llp = NULL;
}


static struct parport_driver spi_lm70llp_drv = {
	.name =		DRVNAME,
	.attach =	spi_lm70llp_attach,
	.detach =	spi_lm70llp_detach,
};

static int __init init_spi_lm70llp(void)
{
	return parport_register_driver(&spi_lm70llp_drv);
}
module_init(init_spi_lm70llp);

static void __exit cleanup_spi_lm70llp(void)
{
	parport_unregister_driver(&spi_lm70llp_drv);
}
module_exit(cleanup_spi_lm70llp);

MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
MODULE_DESCRIPTION(
	"Parport adapter for the National Semiconductor LM70 LLP eval board");
MODULE_LICENSE("GPL");
Commit	Line	Data
78961a57	1	/*
ca632f55	2	* Driver for LM70EVAL-LLP board for the LM70 sensor
78961a57 KB	3	*
	4	* Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
	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.
78961a57 KB	15	*/
	16
	17	#include <linux/init.h>
	18	#include <linux/module.h>
	19	#include <linux/kernel.h>
	20	#include <linux/delay.h>
	21	#include <linux/device.h>
	22	#include <linux/parport.h>
	23	#include <linux/sysfs.h>
	24	#include <linux/workqueue.h>
	25
	26
	27	#include <linux/spi/spi.h>
	28	#include <linux/spi/spi_bitbang.h>
	29
	30
	31	/*
	32	* The LM70 communicates with a host processor using a 3-wire variant of
	33	* the SPI/Microwire bus interface. This driver specifically supports an
	34	* NS LM70 LLP Evaluation Board, interfacing to a PC using its parallel
	35	* port to bitbang an SPI-parport bridge. Accordingly, this is an SPI
	36	* master controller driver. The hwmon/lm70 driver is a "SPI protocol
	37	* driver", layered on top of this one and usable without the lm70llp.
	38	*
2b730051	39	* Datasheet and Schematic:
78961a57 KB	40	* The LM70 is a temperature sensor chip from National Semiconductor; its
78961a57 KB	41	* datasheet is available at http://www.national.com/pf/LM/LM70.html
2b730051 KB	42	* The schematic for this particular board (the LM70EVAL-LLP) is
	43	* available (on page 4) here:
	44	* http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf
78961a57 KB	45	*
	46	* Also see Documentation/spi/spi-lm70llp. The SPI<->parport code here is
	47	* (heavily) based on spi-butterfly by David Brownell.
	48	*
	49	* The LM70 LLP connects to the PC parallel port in the following manner:
	50	*
	51	* Parallel LM70 LLP
	52	* Port Direction JP2 Header
	53	* ----------- --------- ------------
	54	* D0 2 - -
	55	* D1 3 --> V+ 5
	56	* D2 4 --> V+ 5
	57	* D3 5 --> V+ 5
	58	* D4 6 --> V+ 5
	59	* D5 7 --> nCS 8
	60	* D6 8 --> SCLK 3
	61	* D7 9 --> SI/O 5
	62	* GND 25 - GND 7
	63	* Select 13 <-- SI/O 1
	64	*
	65	* Note that parport pin 13 actually gets inverted by the transistor
	66	* arrangement which lets either the parport or the LM70 drive the
2b730051	67	* SI/SO signal (see the schematic for details).
78961a57 KB	68	*/
	69
	70	#define DRVNAME "spi-lm70llp"
	71
	72	#define lm70_INIT 0xBE
	73	#define SIO 0x10
	74	#define nCS 0x20
	75	#define SCLK 0x40
	76
	77	/-------------------------------------------------------------------------/
	78
	79	struct spi_lm70llp {
	80	struct spi_bitbang bitbang;
	81	struct parport *port;
	82	struct pardevice *pd;
	83	struct spi_device *spidev_lm70;
	84	struct spi_board_info info;
49dce689	85	//struct device *dev;
78961a57 KB	86	};
	87
	88	/* REVISIT : ugly global ; provides "exclusive open" facility */
	89	static struct spi_lm70llp *lm70llp;
	90
	91
	92	/-------------------------------------------------------------------/
	93
	94	static inline struct spi_lm70llp spidev_to_pp(struct spi_device spi)
	95	{
	96	return spi->controller_data;
	97	}
	98
	99	/---------------------- LM70 LLP eval board-specific inlines follow /
	100
	101	/* NOTE: we don't actually need to reread the output values, since they'll
	102	* still be what we wrote before. Plus, going through parport builds in
	103	* a ~1ms/operation delay; these SPI transfers could easily be faster.
	104	*/
	105
	106	static inline void deassertCS(struct spi_lm70llp *pp)
	107	{
	108	u8 data = parport_read_data(pp->port);
2b730051 KB	109
2b730051 KB	110	data &= ~0x80; /* pull D7/SI-out low while de-asserted */
78961a57 KB	111	parport_write_data(pp->port, data \| nCS);
	112	}
	113
	114	static inline void assertCS(struct spi_lm70llp *pp)
	115	{
	116	u8 data = parport_read_data(pp->port);
2b730051 KB	117
2b730051 KB	118	data \|= 0x80; /* pull D7/SI-out high so lm70 drives SO-in */
78961a57 KB	119	parport_write_data(pp->port, data & ~nCS);
	120	}
	121
	122	static inline void clkHigh(struct spi_lm70llp *pp)
	123	{
	124	u8 data = parport_read_data(pp->port);
	125	parport_write_data(pp->port, data \| SCLK);
	126	}
	127
	128	static inline void clkLow(struct spi_lm70llp *pp)
	129	{
	130	u8 data = parport_read_data(pp->port);
	131	parport_write_data(pp->port, data & ~SCLK);
	132	}
	133
	134	/------------------------- SPI-LM70-specific inlines ----------------------/
	135
	136	static inline void spidelay(unsigned d)
	137	{
	138	udelay(d);
	139	}
	140
	141	static inline void setsck(struct spi_device *s, int is_on)
	142	{
	143	struct spi_lm70llp *pp = spidev_to_pp(s);
	144
	145	if (is_on)
	146	clkHigh(pp);
	147	else
	148	clkLow(pp);
	149	}
	150
	151	static inline void setmosi(struct spi_device *s, int is_on)
	152	{
	153	/* FIXME update D7 ... this way we can put the chip
	154	* into shutdown mode and read the manufacturer ID,
	155	* but we can't put it back into operational mode.
	156	*/
	157	}
	158
	159	/*
	160	* getmiso:
	161	* Why do we return 0 when the SIO line is high and vice-versa?
	162	* The fact is, the lm70 eval board from NS (which this driver drives),
	163	* is wired in just such a way : when the lm70's SIO goes high, a transistor
	164	* switches it to low reflecting this on the parport (pin 13), and vice-versa.
	165	*/
	166	static inline int getmiso(struct spi_device *s)
	167	{
	168	struct spi_lm70llp *pp = spidev_to_pp(s);
	169	return ((SIO == (parport_read_status(pp->port) & SIO)) ? 0 : 1 );
	170	}
	171	/--------------------------------------------------------------------/
	172
ca632f55	173	#include "spi-bitbang-txrx.h"
78961a57 KB	174
	175	static void lm70_chipselect(struct spi_device *spi, int value)
	176	{
	177	struct spi_lm70llp *pp = spidev_to_pp(spi);
	178
	179	if (value)
	180	assertCS(pp);
	181	else
	182	deassertCS(pp);
	183	}
	184
	185	/*
	186	* Our actual bitbanger routine.
	187	*/
	188	static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
	189	{
04bb2a03	190	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
78961a57 KB	191	}
	192
	193	static void spi_lm70llp_attach(struct parport *p)
	194	{
	195	struct pardevice *pd;
	196	struct spi_lm70llp *pp;
	197	struct spi_master *master;
	198	int status;
	199
	200	if (lm70llp) {
	201	printk(KERN_WARNING
	202	"%s: spi_lm70llp instance already loaded. Aborting.\n",
	203	DRVNAME);
	204	return;
	205	}
	206
	207	/* TODO: this just _assumes_ a lm70 is there ... no probe;
	208	* the lm70 driver could verify it, reading the manf ID.
	209	*/
	210
	211	master = spi_alloc_master(p->physport->dev, sizeof *pp);
	212	if (!master) {
	213	status = -ENOMEM;
	214	goto out_fail;
	215	}
	216	pp = spi_master_get_devdata(master);
	217
78961a57 KB	218	/*
	219	* SPI and bitbang hookup.
	220	*/
94c69f76	221	pp->bitbang.master = master;
78961a57 KB	222	pp->bitbang.chipselect = lm70_chipselect;
	223	pp->bitbang.txrx_word[SPI_MODE_0] = lm70_txrx;
	224	pp->bitbang.flags = SPI_3WIRE;
	225
	226	/*
	227	* Parport hookup
	228	*/
	229	pp->port = p;
	230	pd = parport_register_device(p, DRVNAME,
	231	NULL, NULL, NULL,
	232	PARPORT_FLAG_EXCL, pp);
	233	if (!pd) {
	234	status = -ENOMEM;
	235	goto out_free_master;
	236	}
	237	pp->pd = pd;
	238
	239	status = parport_claim(pd);
	240	if (status < 0)
	241	goto out_parport_unreg;
	242
	243	/*
	244	* Start SPI ...
	245	*/
	246	status = spi_bitbang_start(&pp->bitbang);
	247	if (status < 0) {
	248	printk(KERN_WARNING
	249	"%s: spi_bitbang_start failed with status %d\n",
	250	DRVNAME, status);
	251	goto out_off_and_release;
	252	}
	253
	254	/*
	255	* The modalias name MUST match the device_driver name
	256	* for the bus glue code to match and subsequently bind them.
	257	* We are binding to the generic drivers/hwmon/lm70.c device
	258	* driver.
	259	*/
	260	strcpy(pp->info.modalias, "lm70");
	261	pp->info.max_speed_hz = 6 * 1000 * 1000;
	262	pp->info.chip_select = 0;
	263	pp->info.mode = SPI_3WIRE \| SPI_MODE_0;
	264
	265	/* power up the chip, and let the LM70 control SI/SO */
	266	parport_write_data(pp->port, lm70_INIT);
	267
	268	/* Enable access to our primary data structure via
	269	* the board info's (void *)controller_data.
	270	*/
	271	pp->info.controller_data = pp;
	272	pp->spidev_lm70 = spi_new_device(pp->bitbang.master, &pp->info);
	273	if (pp->spidev_lm70)
	274	dev_dbg(&pp->spidev_lm70->dev, "spidev_lm70 at %s\n",
35f74fca	275	dev_name(&pp->spidev_lm70->dev));
78961a57 KB	276	else {
	277	printk(KERN_WARNING "%s: spi_new_device failed\n", DRVNAME);
	278	status = -ENODEV;
	279	goto out_bitbang_stop;
	280	}
2b730051	281	pp->spidev_lm70->bits_per_word = 8;
78961a57 KB	282
78961a57 KB	283	lm70llp = pp;
78961a57 KB	284	return;
	285
	286	out_bitbang_stop:
	287	spi_bitbang_stop(&pp->bitbang);
	288	out_off_and_release:
	289	/* power down */
	290	parport_write_data(pp->port, 0);
	291	mdelay(10);
	292	parport_release(pp->pd);
	293	out_parport_unreg:
	294	parport_unregister_device(pd);
	295	out_free_master:
	296	(void) spi_master_put(master);
	297	out_fail:
	298	pr_info("%s: spi_lm70llp probe fail, status %d\n", DRVNAME, status);
	299	}
	300
	301	static void spi_lm70llp_detach(struct parport *p)
	302	{
	303	struct spi_lm70llp *pp;
	304
	305	if (!lm70llp \|\| lm70llp->port != p)
	306	return;
	307
	308	pp = lm70llp;
	309	spi_bitbang_stop(&pp->bitbang);
	310
	311	/* power down */
	312	parport_write_data(pp->port, 0);
78961a57 KB	313
	314	parport_release(pp->pd);
	315	parport_unregister_device(pp->pd);
	316
	317	(void) spi_master_put(pp->bitbang.master);
	318
	319	lm70llp = NULL;
	320	}
	321
	322
	323	static struct parport_driver spi_lm70llp_drv = {
	324	.name = DRVNAME,
	325	.attach = spi_lm70llp_attach,
	326	.detach = spi_lm70llp_detach,
	327	};
	328
	329	static int __init init_spi_lm70llp(void)
	330	{
	331	return parport_register_driver(&spi_lm70llp_drv);
	332	}
	333	module_init(init_spi_lm70llp);
	334
	335	static void __exit cleanup_spi_lm70llp(void)
	336	{
	337	parport_unregister_driver(&spi_lm70llp_drv);
	338	}
	339	module_exit(cleanup_spi_lm70llp);
	340
	341	MODULE_AUTHOR("Kaiwan N Billimoria <kaiwan@designergraphix.com>");
	342	MODULE_DESCRIPTION(
	343	"Parport adapter for the National Semiconductor LM70 LLP eval board");
	344	MODULE_LICENSE("GPL");