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

/*
 * Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver
 *
 * Copyright 2012 Analog Devices Inc.
 * Author: Lars-Peter Clausen <[email protected]>
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <asm/unaligned.h>

#define SPI_XCOMM_SETTINGS_LEN_OFFSET		10
#define SPI_XCOMM_SETTINGS_3WIRE		BIT(6)
#define SPI_XCOMM_SETTINGS_CS_HIGH		BIT(5)
#define SPI_XCOMM_SETTINGS_SAMPLE_END		BIT(4)
#define SPI_XCOMM_SETTINGS_CPHA			BIT(3)
#define SPI_XCOMM_SETTINGS_CPOL			BIT(2)
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK	0x3
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_64		0x2
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_16		0x1
#define SPI_XCOMM_SETTINGS_CLOCK_DIV_4		0x0

#define SPI_XCOMM_CMD_UPDATE_CONFIG	0x03
#define SPI_XCOMM_CMD_WRITE		0x04

#define SPI_XCOMM_CLOCK 48000000

struct spi_xcomm {
	struct i2c_client *i2c;

	uint16_t settings;
	uint16_t chipselect;

	unsigned int current_speed;

	uint8_t buf[63];
};

static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len)
{
	uint16_t settings;
	uint8_t *buf = spi_xcomm->buf;

	settings = spi_xcomm->settings;
	settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET;

	buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG;
	put_unaligned_be16(settings, &buf[1]);
	put_unaligned_be16(spi_xcomm->chipselect, &buf[3]);

	return i2c_master_send(spi_xcomm->i2c, buf, 5);
}

static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm,
	struct spi_device *spi, int is_active)
{
	unsigned long cs = spi->chip_select;
	uint16_t chipselect = spi_xcomm->chipselect;

	if (is_active)
		chipselect |= BIT(cs);
	else
		chipselect &= ~BIT(cs);

	spi_xcomm->chipselect = chipselect;
}

static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm,
	struct spi_device *spi, struct spi_transfer *t, unsigned int *settings)
{
	if (t->len > 62)
		return -EINVAL;

	if (t->speed_hz != spi_xcomm->current_speed) {
		unsigned int divider;

		divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz);
		if (divider >= 64)
			*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64;
		else if (divider >= 16)
			*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16;
		else
			*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4;

		spi_xcomm->current_speed = t->speed_hz;
	}

	if (spi->mode & SPI_CPOL)
		*settings |= SPI_XCOMM_SETTINGS_CPOL;
	else
		*settings &= ~SPI_XCOMM_SETTINGS_CPOL;

	if (spi->mode & SPI_CPHA)
		*settings &= ~SPI_XCOMM_SETTINGS_CPHA;
	else
		*settings |= SPI_XCOMM_SETTINGS_CPHA;

	if (spi->mode & SPI_3WIRE)
		*settings |= SPI_XCOMM_SETTINGS_3WIRE;
	else
		*settings &= ~SPI_XCOMM_SETTINGS_3WIRE;

	return 0;
}

static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm,
	struct spi_device *spi, struct spi_transfer *t)
{
	int ret;

	if (t->tx_buf) {
		spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE;
		memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len);

		ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1);
		if (ret < 0)
			return ret;
		else if (ret != t->len + 1)
			return -EIO;
	} else if (t->rx_buf) {
		ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len);
		if (ret < 0)
			return ret;
		else if (ret != t->len)
			return -EIO;
	}

	return t->len;
}

static int spi_xcomm_transfer_one(struct spi_master *master,
	struct spi_message *msg)
{
	struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master);
	unsigned int settings = spi_xcomm->settings;
	struct spi_device *spi = msg->spi;
	unsigned cs_change = 0;
	struct spi_transfer *t;
	bool is_first = true;
	int status = 0;
	bool is_last;

	spi_xcomm_chipselect(spi_xcomm, spi, true);

	list_for_each_entry(t, &msg->transfers, transfer_list) {

		if (!t->tx_buf && !t->rx_buf && t->len) {
			status = -EINVAL;
			break;
		}

		status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings);
		if (status < 0)
			break;

		is_last = list_is_last(&t->transfer_list, &msg->transfers);
		cs_change = t->cs_change;

		if (cs_change ^ is_last)
			settings |= BIT(5);
		else
			settings &= ~BIT(5);

		if (t->rx_buf) {
			spi_xcomm->settings = settings;
			status = spi_xcomm_sync_config(spi_xcomm, t->len);
			if (status < 0)
				break;
		} else if (settings != spi_xcomm->settings || is_first) {
			spi_xcomm->settings = settings;
			status = spi_xcomm_sync_config(spi_xcomm, 0);
			if (status < 0)
				break;
		}

		if (t->len) {
			status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t);

			if (status < 0)
				break;

			if (status > 0)
				msg->actual_length += status;
		}
		status = 0;

		if (t->delay_usecs)
			udelay(t->delay_usecs);

		is_first = false;
	}

	if (status != 0 || !cs_change)
		spi_xcomm_chipselect(spi_xcomm, spi, false);

	msg->status = status;
	spi_finalize_current_message(master);

	return status;
}

static int spi_xcomm_probe(struct i2c_client *i2c,
	const struct i2c_device_id *id)
{
	struct spi_xcomm *spi_xcomm;
	struct spi_master *master;
	int ret;

	master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm));
	if (!master)
		return -ENOMEM;

	spi_xcomm = spi_master_get_devdata(master);
	spi_xcomm->i2c = i2c;

	master->num_chipselect = 16;
	master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE;
	master->bits_per_word_mask = SPI_BPW_MASK(8);
	master->flags = SPI_MASTER_HALF_DUPLEX;
	master->transfer_one_message = spi_xcomm_transfer_one;
	master->dev.of_node = i2c->dev.of_node;
	i2c_set_clientdata(i2c, master);

	ret = devm_spi_register_master(&i2c->dev, master);
	if (ret < 0)
		spi_master_put(master);

	return ret;
}

static const struct i2c_device_id spi_xcomm_ids[] = {
	{ "spi-xcomm" },
	{ },
};
MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids);

static struct i2c_driver spi_xcomm_driver = {
	.driver = {
		.name	= "spi-xcomm",
	},
	.id_table	= spi_xcomm_ids,
	.probe		= spi_xcomm_probe,
};
module_i2c_driver(spi_xcomm_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lars-Peter Clausen <[email protected]>");
MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");
Commit	Line	Data
b3165900 LPC	1	/*
	2	* Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver
	3	*
	4	* Copyright 2012 Analog Devices Inc.
	5	* Author: Lars-Peter Clausen <[email protected]>
	6	*
	7	* Licensed under the GPL-2 or later.
	8	*/
	9
	10	#include <linux/kernel.h>
b3165900 LPC	11	#include <linux/module.h>
	12	#include <linux/delay.h>
	13	#include <linux/i2c.h>
	14	#include <linux/spi/spi.h>
	15	#include <asm/unaligned.h>
	16
	17	#define SPI_XCOMM_SETTINGS_LEN_OFFSET 10
	18	#define SPI_XCOMM_SETTINGS_3WIRE BIT(6)
	19	#define SPI_XCOMM_SETTINGS_CS_HIGH BIT(5)
	20	#define SPI_XCOMM_SETTINGS_SAMPLE_END BIT(4)
	21	#define SPI_XCOMM_SETTINGS_CPHA BIT(3)
	22	#define SPI_XCOMM_SETTINGS_CPOL BIT(2)
	23	#define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK 0x3
	24	#define SPI_XCOMM_SETTINGS_CLOCK_DIV_64 0x2
	25	#define SPI_XCOMM_SETTINGS_CLOCK_DIV_16 0x1
	26	#define SPI_XCOMM_SETTINGS_CLOCK_DIV_4 0x0
	27
	28	#define SPI_XCOMM_CMD_UPDATE_CONFIG 0x03
	29	#define SPI_XCOMM_CMD_WRITE 0x04
	30
	31	#define SPI_XCOMM_CLOCK 48000000
	32
	33	struct spi_xcomm {
	34	struct i2c_client *i2c;
	35
	36	uint16_t settings;
	37	uint16_t chipselect;
	38
	39	unsigned int current_speed;
	40
	41	uint8_t buf[63];
	42	};
	43
	44	static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len)
	45	{
	46	uint16_t settings;
	47	uint8_t *buf = spi_xcomm->buf;
	48
	49	settings = spi_xcomm->settings;
	50	settings \|= len << SPI_XCOMM_SETTINGS_LEN_OFFSET;
	51
	52	buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG;
	53	put_unaligned_be16(settings, &buf[1]);
	54	put_unaligned_be16(spi_xcomm->chipselect, &buf[3]);
	55
	56	return i2c_master_send(spi_xcomm->i2c, buf, 5);
	57	}
	58
	59	static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm,
	60	struct spi_device *spi, int is_active)
	61	{
	62	unsigned long cs = spi->chip_select;
	63	uint16_t chipselect = spi_xcomm->chipselect;
	64
	65	if (is_active)
	66	chipselect \|= BIT(cs);
	67	else
	68	chipselect &= ~BIT(cs);
	69
	70	spi_xcomm->chipselect = chipselect;
	71	}
	72
	73	static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm,
	74	struct spi_device spi, struct spi_transfer t, unsigned int *settings)
75	{
24778be2	76	if (t->len > 62)
b3165900 LPC	77	return -EINVAL;
b3165900 LPC	78
af348519 AL	79	if (t->speed_hz != spi_xcomm->current_speed) {
af348519 AL	80	unsigned int divider;
b3165900	81
af348519	82	divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz);
b3165900 LPC	83	if (divider >= 64)
	84	*settings \|= SPI_XCOMM_SETTINGS_CLOCK_DIV_64;
	85	else if (divider >= 16)
	86	*settings \|= SPI_XCOMM_SETTINGS_CLOCK_DIV_16;
	87	else
	88	*settings \|= SPI_XCOMM_SETTINGS_CLOCK_DIV_4;
	89
af348519	90	spi_xcomm->current_speed = t->speed_hz;
b3165900 LPC	91	}
	92
	93	if (spi->mode & SPI_CPOL)
	94	*settings \|= SPI_XCOMM_SETTINGS_CPOL;
	95	else
	96	*settings &= ~SPI_XCOMM_SETTINGS_CPOL;
	97
	98	if (spi->mode & SPI_CPHA)
	99	*settings &= ~SPI_XCOMM_SETTINGS_CPHA;
	100	else
	101	*settings \|= SPI_XCOMM_SETTINGS_CPHA;
	102
	103	if (spi->mode & SPI_3WIRE)
	104	*settings \|= SPI_XCOMM_SETTINGS_3WIRE;
	105	else
	106	*settings &= ~SPI_XCOMM_SETTINGS_3WIRE;
	107
	108	return 0;
	109	}
	110
	111	static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm,
	112	struct spi_device spi, struct spi_transfer t)
	113	{
	114	int ret;
	115
	116	if (t->tx_buf) {
	117	spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE;
	118	memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len);
	119
	120	ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1);
	121	if (ret < 0)
	122	return ret;
	123	else if (ret != t->len + 1)
	124	return -EIO;
	125	} else if (t->rx_buf) {
	126	ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len);
	127	if (ret < 0)
	128	return ret;
	129	else if (ret != t->len)
	130	return -EIO;
	131	}
	132
	133	return t->len;
	134	}
	135
	136	static int spi_xcomm_transfer_one(struct spi_master *master,
	137	struct spi_message *msg)
	138	{
	139	struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master);
	140	unsigned int settings = spi_xcomm->settings;
	141	struct spi_device *spi = msg->spi;
	142	unsigned cs_change = 0;
	143	struct spi_transfer *t;
	144	bool is_first = true;
	145	int status = 0;
	146	bool is_last;
	147
b3165900 LPC	148	spi_xcomm_chipselect(spi_xcomm, spi, true);
	149
	150	list_for_each_entry(t, &msg->transfers, transfer_list) {
	151
	152	if (!t->tx_buf && !t->rx_buf && t->len) {
	153	status = -EINVAL;
	154	break;
	155	}
	156
	157	status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings);
	158	if (status < 0)
	159	break;
	160
	161	is_last = list_is_last(&t->transfer_list, &msg->transfers);
	162	cs_change = t->cs_change;
	163
	164	if (cs_change ^ is_last)
	165	settings \|= BIT(5);
	166	else
	167	settings &= ~BIT(5);
	168
	169	if (t->rx_buf) {
	170	spi_xcomm->settings = settings;
	171	status = spi_xcomm_sync_config(spi_xcomm, t->len);
	172	if (status < 0)
	173	break;
	174	} else if (settings != spi_xcomm->settings \|\| is_first) {
	175	spi_xcomm->settings = settings;
	176	status = spi_xcomm_sync_config(spi_xcomm, 0);
	177	if (status < 0)
	178	break;
	179	}
	180
	181	if (t->len) {
	182	status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t);
	183
	184	if (status < 0)
	185	break;
	186
	187	if (status > 0)
	188	msg->actual_length += status;
	189	}
	190	status = 0;
	191
	192	if (t->delay_usecs)
	193	udelay(t->delay_usecs);
	194
	195	is_first = false;
	196	}
	197
	198	if (status != 0 \|\| !cs_change)
	199	spi_xcomm_chipselect(spi_xcomm, spi, false);
	200
	201	msg->status = status;
	202	spi_finalize_current_message(master);
	203
	204	return status;
	205	}
	206
fd4a319b	207	static int spi_xcomm_probe(struct i2c_client *i2c,
b3165900 LPC	208	const struct i2c_device_id *id)
	209	{
	210	struct spi_xcomm *spi_xcomm;
	211	struct spi_master *master;
	212	int ret;
	213
	214	master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm));
	215	if (!master)
	216	return -ENOMEM;
	217
	218	spi_xcomm = spi_master_get_devdata(master);
	219	spi_xcomm->i2c = i2c;
	220
	221	master->num_chipselect = 16;
	222	master->mode_bits = SPI_CPHA \| SPI_CPOL \| SPI_3WIRE;
24778be2	223	master->bits_per_word_mask = SPI_BPW_MASK(8);
b3165900	224	master->flags = SPI_MASTER_HALF_DUPLEX;
b3165900 LPC	225	master->transfer_one_message = spi_xcomm_transfer_one;
	226	master->dev.of_node = i2c->dev.of_node;
	227	i2c_set_clientdata(i2c, master);
	228
4cc16085	229	ret = devm_spi_register_master(&i2c->dev, master);
b3165900 LPC	230	if (ret < 0)
	231	spi_master_put(master);
	232
	233	return ret;
	234	}
	235
b3165900 LPC	236	static const struct i2c_device_id spi_xcomm_ids[] = {
	237	{ "spi-xcomm" },
	238	{ },
	239	};
98c7863c	240	MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids);
b3165900 LPC	241
	242	static struct i2c_driver spi_xcomm_driver = {
	243	.driver = {
	244	.name = "spi-xcomm",
b3165900 LPC	245	},
	246	.id_table = spi_xcomm_ids,
	247	.probe = spi_xcomm_probe,
b3165900 LPC	248	};
	249	module_i2c_driver(spi_xcomm_driver);
	250
	251	MODULE_LICENSE("GPL");
	252	MODULE_AUTHOR("Lars-Peter Clausen <[email protected]>");
	253	MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");