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

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