[deliverable/linux.git] / drivers / spi / spi-gpio.c

/*
 * SPI master driver using generic bitbanged GPIO
 *
 * Copyright (C) 2006,2008 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/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>

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


/*
 * This bitbanging SPI master driver should help make systems usable
 * when a native hardware SPI engine is not available, perhaps because
 * its driver isn't yet working or because the I/O pins it requires
 * are used for other purposes.
 *
 * platform_device->driver_data ... points to spi_gpio
 *
 * spi->controller_state ... reserved for bitbang framework code
 * spi->controller_data ... holds chipselect GPIO
 *
 * spi->master->dev.driver_data ... points to spi_gpio->bitbang
 */

struct spi_gpio {
	struct spi_bitbang		bitbang;
	struct spi_gpio_platform_data	pdata;
	struct platform_device		*pdev;
};

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

/*
 * Because the overhead of going through four GPIO procedure calls
 * per transferred bit can make performance a problem, this code
 * is set up so that you can use it in either of two ways:
 *
 *   - The slow generic way:  set up platform_data to hold the GPIO
 *     numbers used for MISO/MOSI/SCK, and issue procedure calls for
 *     each of them.  This driver can handle several such busses.
 *
 *   - The quicker inlined way:  only helps with platform GPIO code
 *     that inlines operations for constant GPIOs.  This can give
 *     you tight (fast!) inner loops, but each such bus needs a
 *     new driver.  You'll define a new C file, with Makefile and
 *     Kconfig support; the C code can be a total of six lines:
 *
 *		#define DRIVER_NAME	"myboard_spi2"
 *		#define	SPI_MISO_GPIO	119
 *		#define	SPI_MOSI_GPIO	120
 *		#define	SPI_SCK_GPIO	121
 *		#define	SPI_N_CHIPSEL	4
 *		#include "spi-gpio.c"
 */

#ifndef DRIVER_NAME
#define DRIVER_NAME	"spi_gpio"

#define GENERIC_BITBANG	/* vs tight inlines */

/* all functions referencing these symbols must define pdata */
#define SPI_MISO_GPIO	((pdata)->miso)
#define SPI_MOSI_GPIO	((pdata)->mosi)
#define SPI_SCK_GPIO	((pdata)->sck)

#define SPI_N_CHIPSEL	((pdata)->num_chipselect)

#endif

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

static inline const struct spi_gpio_platform_data * __pure
spi_to_pdata(const struct spi_device *spi)
{
	const struct spi_bitbang	*bang;
	const struct spi_gpio		*spi_gpio;

	bang = spi_master_get_devdata(spi->master);
	spi_gpio = container_of(bang, struct spi_gpio, bitbang);
	return &spi_gpio->pdata;
}

/* this is #defined to avoid unused-variable warnings when inlining */
#define pdata		spi_to_pdata(spi)

static inline void setsck(const struct spi_device *spi, int is_on)
{
	gpio_set_value(SPI_SCK_GPIO, is_on);
}

static inline void setmosi(const struct spi_device *spi, int is_on)
{
	gpio_set_value(SPI_MOSI_GPIO, is_on);
}

static inline int getmiso(const struct spi_device *spi)
{
	return !!gpio_get_value(SPI_MISO_GPIO);
}

#undef pdata

/*
 * NOTE:  this clocks "as fast as we can".  It "should" be a function of the
 * requested device clock.  Software overhead means we usually have trouble
 * reaching even one Mbit/sec (except when we can inline bitops), so for now
 * we'll just assume we never need additional per-bit slowdowns.
 */
#define spidelay(nsecs)	do {} while (0)

#include "spi-bitbang-txrx.h"

/*
 * These functions can leverage inline expansion of GPIO calls to shrink
 * costs for a txrx bit, often by factors of around ten (by instruction
 * count).  That is particularly visible for larger word sizes, but helps
 * even with default 8-bit words.
 *
 * REVISIT overheads calling these functions for each word also have
 * significant performance costs.  Having txrx_bufs() calls that inline
 * the txrx_word() logic would help performance, e.g. on larger blocks
 * used with flash storage or MMC/SD.  There should also be ways to make
 * GCC be less stupid about reloading registers inside the I/O loops,
 * even without inlined GPIO calls; __attribute__((hot)) on GCC 4.3?
 */

static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
}

static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
}

static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
}

static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
}

/*
 * These functions do not call setmosi or getmiso if respective flag
 * (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to
 * call when such pin is not present or defined in the controller.
 * A separate set of callbacks is defined to get highest possible
 * speed in the generic case (when both MISO and MOSI lines are
 * available), as optimiser will remove the checks when argument is
 * constant.
 */

static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	unsigned flags = spi->master->flags;
	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
}

static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	unsigned flags = spi->master->flags;
	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
}

static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	unsigned flags = spi->master->flags;
	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
}

static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
		unsigned nsecs, u32 word, u8 bits)
{
	unsigned flags = spi->master->flags;
	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
}

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

static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
{
	unsigned long cs = (unsigned long) spi->controller_data;

	/* set initial clock polarity */
	if (is_active)
		setsck(spi, spi->mode & SPI_CPOL);

	if (cs != SPI_GPIO_NO_CHIPSELECT) {
		/* SPI is normally active-low */
		gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
	}
}

static int spi_gpio_setup(struct spi_device *spi)
{
	unsigned long	cs = (unsigned long) spi->controller_data;
	int		status = 0;

	if (spi->bits_per_word > 32)
		return -EINVAL;

	if (!spi->controller_state) {
		if (cs != SPI_GPIO_NO_CHIPSELECT) {
			status = gpio_request(cs, dev_name(&spi->dev));
			if (status)
				return status;
			status = gpio_direction_output(cs,
					!(spi->mode & SPI_CS_HIGH));
		}
	}
	if (!status)
		status = spi_bitbang_setup(spi);
	if (status) {
		if (!spi->controller_state && cs != SPI_GPIO_NO_CHIPSELECT)
			gpio_free(cs);
	}
	return status;
}

static void spi_gpio_cleanup(struct spi_device *spi)
{
	unsigned long	cs = (unsigned long) spi->controller_data;

	if (cs != SPI_GPIO_NO_CHIPSELECT)
		gpio_free(cs);
	spi_bitbang_cleanup(spi);
}

static int __devinit spi_gpio_alloc(unsigned pin, const char *label, bool is_in)
{
	int value;

	value = gpio_request(pin, label);
	if (value == 0) {
		if (is_in)
			value = gpio_direction_input(pin);
		else
			value = gpio_direction_output(pin, 0);
	}
	return value;
}

static int __devinit
spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label,
	u16 *res_flags)
{
	int value;

	/* NOTE:  SPI_*_GPIO symbols may reference "pdata" */

	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) {
		value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false);
		if (value)
			goto done;
	} else {
		/* HW configuration without MOSI pin */
		*res_flags |= SPI_MASTER_NO_TX;
	}

	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) {
		value = spi_gpio_alloc(SPI_MISO_GPIO, label, true);
		if (value)
			goto free_mosi;
	} else {
		/* HW configuration without MISO pin */
		*res_flags |= SPI_MASTER_NO_RX;
	}

	value = spi_gpio_alloc(SPI_SCK_GPIO, label, false);
	if (value)
		goto free_miso;

	goto done;

free_miso:
	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
		gpio_free(SPI_MISO_GPIO);
free_mosi:
	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
		gpio_free(SPI_MOSI_GPIO);
done:
	return value;
}

static int __devinit spi_gpio_probe(struct platform_device *pdev)
{
	int				status;
	struct spi_master		*master;
	struct spi_gpio			*spi_gpio;
	struct spi_gpio_platform_data	*pdata;
	u16 master_flags = 0;

	pdata = pdev->dev.platform_data;
#ifdef GENERIC_BITBANG
	if (!pdata || !pdata->num_chipselect)
		return -ENODEV;
#endif

	status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags);
	if (status < 0)
		return status;

	master = spi_alloc_master(&pdev->dev, sizeof *spi_gpio);
	if (!master) {
		status = -ENOMEM;
		goto gpio_free;
	}
	spi_gpio = spi_master_get_devdata(master);
	platform_set_drvdata(pdev, spi_gpio);

	spi_gpio->pdev = pdev;
	if (pdata)
		spi_gpio->pdata = *pdata;

	master->flags = master_flags;
	master->bus_num = pdev->id;
	master->num_chipselect = SPI_N_CHIPSEL;
	master->setup = spi_gpio_setup;
	master->cleanup = spi_gpio_cleanup;

	spi_gpio->bitbang.master = spi_master_get(master);
	spi_gpio->bitbang.chipselect = spi_gpio_chipselect;

	if ((master_flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX)) == 0) {
		spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
		spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
		spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
		spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
	} else {
		spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
		spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;
		spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;
		spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
	}
	spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
	spi_gpio->bitbang.flags = SPI_CS_HIGH;

	status = spi_bitbang_start(&spi_gpio->bitbang);
	if (status < 0) {
		spi_master_put(spi_gpio->bitbang.master);
gpio_free:
		if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
			gpio_free(SPI_MISO_GPIO);
		if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
			gpio_free(SPI_MOSI_GPIO);
		gpio_free(SPI_SCK_GPIO);
		spi_master_put(master);
	}

	return status;
}

static int __devexit spi_gpio_remove(struct platform_device *pdev)
{
	struct spi_gpio			*spi_gpio;
	struct spi_gpio_platform_data	*pdata;
	int				status;

	spi_gpio = platform_get_drvdata(pdev);
	pdata = pdev->dev.platform_data;

	/* stop() unregisters child devices too */
	status = spi_bitbang_stop(&spi_gpio->bitbang);
	spi_master_put(spi_gpio->bitbang.master);

	platform_set_drvdata(pdev, NULL);

	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
		gpio_free(SPI_MISO_GPIO);
	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
		gpio_free(SPI_MOSI_GPIO);
	gpio_free(SPI_SCK_GPIO);

	return status;
}

MODULE_ALIAS("platform:" DRIVER_NAME);

static struct platform_driver spi_gpio_driver = {
	.driver.name	= DRIVER_NAME,
	.driver.owner	= THIS_MODULE,
	.probe		= spi_gpio_probe,
	.remove		= __devexit_p(spi_gpio_remove),
};
module_platform_driver(spi_gpio_driver);

MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO ");
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");
Commit	Line	Data
d29389de	1	/*
ca632f55	2	* SPI master driver using generic bitbanged GPIO
d29389de DB	3	*
	4	* Copyright (C) 2006,2008 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	*/
	20	#include <linux/kernel.h>
d7614de4	21	#include <linux/module.h>
d29389de DB	22	#include <linux/init.h>
	23	#include <linux/platform_device.h>
	24	#include <linux/gpio.h>
	25
	26	#include <linux/spi/spi.h>
	27	#include <linux/spi/spi_bitbang.h>
	28	#include <linux/spi/spi_gpio.h>
	29
	30
	31	/*
	32	* This bitbanging SPI master driver should help make systems usable
	33	* when a native hardware SPI engine is not available, perhaps because
	34	* its driver isn't yet working or because the I/O pins it requires
	35	* are used for other purposes.
	36	*
	37	* platform_device->driver_data ... points to spi_gpio
	38	*
	39	* spi->controller_state ... reserved for bitbang framework code
	40	* spi->controller_data ... holds chipselect GPIO
	41	*
	42	* spi->master->dev.driver_data ... points to spi_gpio->bitbang
	43	*/
	44
	45	struct spi_gpio {
	46	struct spi_bitbang bitbang;
	47	struct spi_gpio_platform_data pdata;
	48	struct platform_device *pdev;
	49	};
	50
	51	/----------------------------------------------------------------------/
	52
	53	/*
	54	* Because the overhead of going through four GPIO procedure calls
	55	* per transferred bit can make performance a problem, this code
	56	* is set up so that you can use it in either of two ways:
	57	*
	58	* - The slow generic way: set up platform_data to hold the GPIO
	59	* numbers used for MISO/MOSI/SCK, and issue procedure calls for
	60	* each of them. This driver can handle several such busses.
	61	*
	62	* - The quicker inlined way: only helps with platform GPIO code
	63	* that inlines operations for constant GPIOs. This can give
	64	* you tight (fast!) inner loops, but each such bus needs a
	65	* new driver. You'll define a new C file, with Makefile and
	66	* Kconfig support; the C code can be a total of six lines:
	67	*
	68	* #define DRIVER_NAME "myboard_spi2"
	69	* #define SPI_MISO_GPIO 119
	70	* #define SPI_MOSI_GPIO 120
	71	* #define SPI_SCK_GPIO 121
	72	* #define SPI_N_CHIPSEL 4
ca632f55	73	* #include "spi-gpio.c"
d29389de DB	74	*/
	75
	76	#ifndef DRIVER_NAME
	77	#define DRIVER_NAME "spi_gpio"
	78
	79	#define GENERIC_BITBANG /* vs tight inlines */
	80
	81	/* all functions referencing these symbols must define pdata */
	82	#define SPI_MISO_GPIO ((pdata)->miso)
	83	#define SPI_MOSI_GPIO ((pdata)->mosi)
	84	#define SPI_SCK_GPIO ((pdata)->sck)
	85
	86	#define SPI_N_CHIPSEL ((pdata)->num_chipselect)
	87
	88	#endif
	89
	90	/----------------------------------------------------------------------/
	91
	92	static inline const struct spi_gpio_platform_data * __pure
	93	spi_to_pdata(const struct spi_device *spi)
	94	{
	95	const struct spi_bitbang *bang;
	96	const struct spi_gpio *spi_gpio;
	97
	98	bang = spi_master_get_devdata(spi->master);
	99	spi_gpio = container_of(bang, struct spi_gpio, bitbang);
	100	return &spi_gpio->pdata;
	101	}
	102
	103	/* this is #defined to avoid unused-variable warnings when inlining */
	104	#define pdata spi_to_pdata(spi)
	105
	106	static inline void setsck(const struct spi_device *spi, int is_on)
	107	{
	108	gpio_set_value(SPI_SCK_GPIO, is_on);
	109	}
	110
	111	static inline void setmosi(const struct spi_device *spi, int is_on)
	112	{
	113	gpio_set_value(SPI_MOSI_GPIO, is_on);
	114	}
	115
	116	static inline int getmiso(const struct spi_device *spi)
	117	{
be50344e	118	return !!gpio_get_value(SPI_MISO_GPIO);
d29389de DB	119	}
	120
	121	#undef pdata
	122
	123	/*
	124	* NOTE: this clocks "as fast as we can". It "should" be a function of the
	125	* requested device clock. Software overhead means we usually have trouble
	126	* reaching even one Mbit/sec (except when we can inline bitops), so for now
	127	* we'll just assume we never need additional per-bit slowdowns.
	128	*/
	129	#define spidelay(nsecs) do {} while (0)
	130
ca632f55	131	#include "spi-bitbang-txrx.h"
d29389de DB	132
	133	/*
	134	* These functions can leverage inline expansion of GPIO calls to shrink
	135	* costs for a txrx bit, often by factors of around ten (by instruction
	136	* count). That is particularly visible for larger word sizes, but helps
	137	* even with default 8-bit words.
	138	*
	139	* REVISIT overheads calling these functions for each word also have
	140	* significant performance costs. Having txrx_bufs() calls that inline
	141	* the txrx_word() logic would help performance, e.g. on larger blocks
	142	* used with flash storage or MMC/SD. There should also be ways to make
	143	* GCC be less stupid about reloading registers inside the I/O loops,
	144	* even without inlined GPIO calls; __attribute__((hot)) on GCC 4.3?
	145	*/
	146
	147	static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,
	148	unsigned nsecs, u32 word, u8 bits)
	149	{
04bb2a03	150	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
d29389de DB	151	}
	152
	153	static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,
	154	unsigned nsecs, u32 word, u8 bits)
	155	{
04bb2a03	156	return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
d29389de DB	157	}
	158
	159	static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,
	160	unsigned nsecs, u32 word, u8 bits)
	161	{
04bb2a03	162	return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
d29389de DB	163	}
	164
	165	static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,
	166	unsigned nsecs, u32 word, u8 bits)
	167	{
04bb2a03	168	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
d29389de DB	169	}
d29389de DB	170
3c8e1a84 MS	171	/*
	172	* These functions do not call setmosi or getmiso if respective flag
	173	* (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to
	174	* call when such pin is not present or defined in the controller.
	175	* A separate set of callbacks is defined to get highest possible
	176	* speed in the generic case (when both MISO and MOSI lines are
	177	* available), as optimiser will remove the checks when argument is
	178	* constant.
	179	*/
	180
	181	static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,
	182	unsigned nsecs, u32 word, u8 bits)
	183	{
	184	unsigned flags = spi->master->flags;
	185	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
	186	}
	187
	188	static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,
	189	unsigned nsecs, u32 word, u8 bits)
	190	{
	191	unsigned flags = spi->master->flags;
	192	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
	193	}
	194
	195	static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,
	196	unsigned nsecs, u32 word, u8 bits)
	197	{
	198	unsigned flags = spi->master->flags;
	199	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
	200	}
	201
	202	static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
	203	unsigned nsecs, u32 word, u8 bits)
	204	{
	205	unsigned flags = spi->master->flags;
	206	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
	207	}
	208
d29389de DB	209	/----------------------------------------------------------------------/
	210
	211	static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
	212	{
	213	unsigned long cs = (unsigned long) spi->controller_data;
	214
	215	/* set initial clock polarity */
	216	if (is_active)
	217	setsck(spi, spi->mode & SPI_CPOL);
	218
bfb9bcdb MB	219	if (cs != SPI_GPIO_NO_CHIPSELECT) {
	220	/* SPI is normally active-low */
	221	gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
	222	}
d29389de DB	223	}
	224
	225	static int spi_gpio_setup(struct spi_device *spi)
	226	{
	227	unsigned long cs = (unsigned long) spi->controller_data;
	228	int status = 0;
	229
	230	if (spi->bits_per_word > 32)
	231	return -EINVAL;
	232
	233	if (!spi->controller_state) {
bfb9bcdb MB	234	if (cs != SPI_GPIO_NO_CHIPSELECT) {
	235	status = gpio_request(cs, dev_name(&spi->dev));
	236	if (status)
	237	return status;
05644147 UKK	238	status = gpio_direction_output(cs,
05644147 UKK	239	!(spi->mode & SPI_CS_HIGH));
bfb9bcdb	240	}
d29389de DB	241	}
	242	if (!status)
	243	status = spi_bitbang_setup(spi);
	244	if (status) {
bfb9bcdb	245	if (!spi->controller_state && cs != SPI_GPIO_NO_CHIPSELECT)
d29389de DB	246	gpio_free(cs);
	247	}
	248	return status;
	249	}
	250
	251	static void spi_gpio_cleanup(struct spi_device *spi)
	252	{
	253	unsigned long cs = (unsigned long) spi->controller_data;
	254
bfb9bcdb MB	255	if (cs != SPI_GPIO_NO_CHIPSELECT)
bfb9bcdb MB	256	gpio_free(cs);
d29389de DB	257	spi_bitbang_cleanup(spi);
	258	}
	259
c65b53ba	260	static int __devinit spi_gpio_alloc(unsigned pin, const char *label, bool is_in)
d29389de DB	261	{
	262	int value;
	263
	264	value = gpio_request(pin, label);
	265	if (value == 0) {
	266	if (is_in)
	267	value = gpio_direction_input(pin);
	268	else
	269	value = gpio_direction_output(pin, 0);
	270	}
	271	return value;
	272	}
	273
c65b53ba	274	static int __devinit
3c8e1a84 MS	275	spi_gpio_request(struct spi_gpio_platform_data pdata, const char label,
3c8e1a84 MS	276	u16 *res_flags)
d29389de DB	277	{
	278	int value;
	279
	280	/* NOTE: SPI__GPIO symbols may reference "pdata" /
	281
3c8e1a84 MS	282	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) {
	283	value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false);
	284	if (value)
	285	goto done;
	286	} else {
	287	/* HW configuration without MOSI pin */
	288	*res_flags \|= SPI_MASTER_NO_TX;
	289	}
d29389de	290
3c8e1a84 MS	291	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) {
	292	value = spi_gpio_alloc(SPI_MISO_GPIO, label, true);
	293	if (value)
	294	goto free_mosi;
	295	} else {
	296	/* HW configuration without MISO pin */
	297	*res_flags \|= SPI_MASTER_NO_RX;
	298	}
d29389de DB	299
	300	value = spi_gpio_alloc(SPI_SCK_GPIO, label, false);
	301	if (value)
	302	goto free_miso;
	303
	304	goto done;
	305
	306	free_miso:
3c8e1a84 MS	307	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
3c8e1a84 MS	308	gpio_free(SPI_MISO_GPIO);
d29389de	309	free_mosi:
3c8e1a84 MS	310	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
3c8e1a84 MS	311	gpio_free(SPI_MOSI_GPIO);
d29389de DB	312	done:
	313	return value;
	314	}
	315
940ab889	316	static int __devinit spi_gpio_probe(struct platform_device *pdev)
d29389de DB	317	{
	318	int status;
	319	struct spi_master *master;
	320	struct spi_gpio *spi_gpio;
	321	struct spi_gpio_platform_data *pdata;
3c8e1a84	322	u16 master_flags = 0;
d29389de DB	323
	324	pdata = pdev->dev.platform_data;
	325	#ifdef GENERIC_BITBANG
	326	if (!pdata \|\| !pdata->num_chipselect)
	327	return -ENODEV;
	328	#endif
	329
3c8e1a84	330	status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags);
d29389de DB	331	if (status < 0)
	332	return status;
	333
	334	master = spi_alloc_master(&pdev->dev, sizeof *spi_gpio);
	335	if (!master) {
	336	status = -ENOMEM;
	337	goto gpio_free;
	338	}
	339	spi_gpio = spi_master_get_devdata(master);
	340	platform_set_drvdata(pdev, spi_gpio);
	341
	342	spi_gpio->pdev = pdev;
	343	if (pdata)
	344	spi_gpio->pdata = *pdata;
	345
3c8e1a84	346	master->flags = master_flags;
d29389de DB	347	master->bus_num = pdev->id;
	348	master->num_chipselect = SPI_N_CHIPSEL;
	349	master->setup = spi_gpio_setup;
	350	master->cleanup = spi_gpio_cleanup;
	351
	352	spi_gpio->bitbang.master = spi_master_get(master);
	353	spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
3c8e1a84	354
23699f98	355	if ((master_flags & (SPI_MASTER_NO_TX \| SPI_MASTER_NO_RX)) == 0) {
3c8e1a84 MS	356	spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
	357	spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
	358	spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
	359	spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
	360	} else {
	361	spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
	362	spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;
	363	spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;
	364	spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
	365	}
d29389de DB	366	spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
	367	spi_gpio->bitbang.flags = SPI_CS_HIGH;
	368
	369	status = spi_bitbang_start(&spi_gpio->bitbang);
	370	if (status < 0) {
	371	spi_master_put(spi_gpio->bitbang.master);
	372	gpio_free:
3c8e1a84 MS	373	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
	374	gpio_free(SPI_MISO_GPIO);
	375	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
	376	gpio_free(SPI_MOSI_GPIO);
d29389de DB	377	gpio_free(SPI_SCK_GPIO);
	378	spi_master_put(master);
	379	}
	380
	381	return status;
	382	}
	383
940ab889	384	static int __devexit spi_gpio_remove(struct platform_device *pdev)
d29389de DB	385	{
	386	struct spi_gpio *spi_gpio;
	387	struct spi_gpio_platform_data *pdata;
	388	int status;
	389
	390	spi_gpio = platform_get_drvdata(pdev);
	391	pdata = pdev->dev.platform_data;
	392
	393	/* stop() unregisters child devices too */
	394	status = spi_bitbang_stop(&spi_gpio->bitbang);
	395	spi_master_put(spi_gpio->bitbang.master);
	396
	397	platform_set_drvdata(pdev, NULL);
	398
3c8e1a84 MS	399	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
	400	gpio_free(SPI_MISO_GPIO);
	401	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
	402	gpio_free(SPI_MOSI_GPIO);
d29389de DB	403	gpio_free(SPI_SCK_GPIO);
	404
	405	return status;
	406	}
	407
	408	MODULE_ALIAS("platform:" DRIVER_NAME);
	409
	410	static struct platform_driver spi_gpio_driver = {
	411	.driver.name = DRIVER_NAME,
	412	.driver.owner = THIS_MODULE,
940ab889 GL	413	.probe = spi_gpio_probe,
940ab889 GL	414	.remove = __devexit_p(spi_gpio_remove),
d29389de	415	};
940ab889	416	module_platform_driver(spi_gpio_driver);
d29389de DB	417
	418	MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO ");
	419	MODULE_AUTHOR("David Brownell");
	420	MODULE_LICENSE("GPL");