[u-boot.git] / drivers / i2c / mvtwsi.c

/*
 * Driver for the TWSI (i2c) controller found on the Marvell
 * orion5x and kirkwood SoC families.
 *
 * Author: Albert Aribaud <[email protected]>
 * Copyright (c) 2010 Albert Aribaud.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <i2c.h>
#include <asm/errno.h>
#include <asm/io.h>

/*
 * include a file that will provide CONFIG_I2C_MVTWSI_BASE
 * and possibly other settings
 */

#if defined(CONFIG_ORION5X)
#include <asm/arch/orion5x.h>
#elif (defined(CONFIG_KIRKWOOD) || defined(CONFIG_ARMADA_XP))
#include <asm/arch/soc.h>
#elif defined(CONFIG_SUNXI)
#include <asm/arch/i2c.h>
#else
#error Driver mvtwsi not supported by SoC or board
#endif

/*
 * TWSI register structure
 */

#ifdef CONFIG_SUNXI

struct  mvtwsi_registers {
	u32 slave_address;
	u32 xtnd_slave_addr;
	u32 data;
	u32 control;
	u32 status;
	u32 baudrate;
	u32 soft_reset;
};

#else

struct  mvtwsi_registers {
	u32 slave_address;
	u32 data;
	u32 control;
	union {
		u32 status;	/* when reading */
		u32 baudrate;	/* when writing */
	};
	u32 xtnd_slave_addr;
	u32 reserved[2];
	u32 soft_reset;
};

#endif

/*
 * Control register fields
 */

#define	MVTWSI_CONTROL_ACK	0x00000004
#define	MVTWSI_CONTROL_IFLG	0x00000008
#define	MVTWSI_CONTROL_STOP	0x00000010
#define	MVTWSI_CONTROL_START	0x00000020
#define	MVTWSI_CONTROL_TWSIEN	0x00000040
#define	MVTWSI_CONTROL_INTEN	0x00000080

/*
 * Status register values -- only those expected in normal master
 * operation on non-10-bit-address devices; whatever status we don't
 * expect in nominal conditions (bus errors, arbitration losses,
 * missing ACKs...) we just pass back to the caller as an error
 * code.
 */

#define	MVTWSI_STATUS_START		0x08
#define	MVTWSI_STATUS_REPEATED_START	0x10
#define	MVTWSI_STATUS_ADDR_W_ACK	0x18
#define	MVTWSI_STATUS_DATA_W_ACK	0x28
#define	MVTWSI_STATUS_ADDR_R_ACK	0x40
#define	MVTWSI_STATUS_ADDR_R_NAK	0x48
#define	MVTWSI_STATUS_DATA_R_ACK	0x50
#define	MVTWSI_STATUS_DATA_R_NAK	0x58
#define	MVTWSI_STATUS_IDLE		0xF8

/*
 * The single instance of the controller we'll be dealing with
 */

static struct  mvtwsi_registers *twsi =
	(struct  mvtwsi_registers *) CONFIG_I2C_MVTWSI_BASE;

/*
 * Returned statuses are 0 for success and nonzero otherwise.
 * Currently, cmd_i2c and cmd_eeprom do not interpret an error status.
 * Thus to ease debugging, the return status contains some debug info:
 * - bits 31..24 are error class: 1 is timeout, 2 is 'status mismatch'.
 * - bits 23..16 are the last value of the control register.
 * - bits 15..8 are the last value of the status register.
 * - bits 7..0 are the expected value of the status register.
 */

#define MVTWSI_ERROR_WRONG_STATUS	0x01
#define MVTWSI_ERROR_TIMEOUT		0x02

#define MVTWSI_ERROR(ec, lc, ls, es) (((ec << 24) & 0xFF000000) | \
	((lc << 16) & 0x00FF0000) | ((ls<<8) & 0x0000FF00) | (es & 0xFF))

/*
 * Wait for IFLG to raise, or return 'timeout'; then if status is as expected,
 * return 0 (ok) or return 'wrong status'.
 */
static int twsi_wait(int expected_status)
{
	int control, status;
	int timeout = 1000;

	do {
		control = readl(&twsi->control);
		if (control & MVTWSI_CONTROL_IFLG) {
			status = readl(&twsi->status);
			if (status == expected_status)
				return 0;
			else
				return MVTWSI_ERROR(
					MVTWSI_ERROR_WRONG_STATUS,
					control, status, expected_status);
		}
		udelay(10); /* one clock cycle at 100 kHz */
	} while (timeout--);
	status = readl(&twsi->status);
	return MVTWSI_ERROR(
		MVTWSI_ERROR_TIMEOUT, control, status, expected_status);
}

/*
 * These flags are ORed to any write to the control register
 * They allow global setting of TWSIEN and ACK.
 * By default none are set.
 * twsi_start() sets TWSIEN (in case the controller was disabled)
 * twsi_recv() sets ACK or resets it depending on expected status.
 */
static u8 twsi_control_flags = MVTWSI_CONTROL_TWSIEN;

/*
 * Assert the START condition, either in a single I2C transaction
 * or inside back-to-back ones (repeated starts).
 */
static int twsi_start(int expected_status)
{
	/* globally set TWSIEN in case it was not */
	twsi_control_flags |= MVTWSI_CONTROL_TWSIEN;
	/* assert START */
	writel(twsi_control_flags | MVTWSI_CONTROL_START, &twsi->control);
	/* wait for controller to process START */
	return twsi_wait(expected_status);
}

/*
 * Send a byte (i2c address or data).
 */
static int twsi_send(u8 byte, int expected_status)
{
	/* put byte in data register for sending */
	writel(byte, &twsi->data);
	/* clear any pending interrupt -- that'll cause sending */
	writel(twsi_control_flags, &twsi->control);
	/* wait for controller to receive byte and check ACK */
	return twsi_wait(expected_status);
}

/*
 * Receive a byte.
 * Global mvtwsi_control_flags variable says if we should ack or nak.
 */
static int twsi_recv(u8 *byte)
{
	int expected_status, status;

	/* compute expected status based on ACK bit in global control flags */
	if (twsi_control_flags & MVTWSI_CONTROL_ACK)
		expected_status = MVTWSI_STATUS_DATA_R_ACK;
	else
		expected_status = MVTWSI_STATUS_DATA_R_NAK;
	/* acknowledge *previous state* and launch receive */
	writel(twsi_control_flags, &twsi->control);
	/* wait for controller to receive byte and assert ACK or NAK */
	status = twsi_wait(expected_status);
	/* if we did receive expected byte then store it */
	if (status == 0)
		*byte = readl(&twsi->data);
	/* return status */
	return status;
}

/*
 * Assert the STOP condition.
 * This is also used to force the bus back in idle (SDA=SCL=1).
 */
static int twsi_stop(int status)
{
	int control, stop_status;
	int timeout = 1000;

	/* assert STOP */
	control = MVTWSI_CONTROL_TWSIEN | MVTWSI_CONTROL_STOP;
	writel(control, &twsi->control);
	/* wait for IDLE; IFLG won't rise so twsi_wait() is no use. */
	do {
		stop_status = readl(&twsi->status);
		if (stop_status == MVTWSI_STATUS_IDLE)
			break;
		udelay(10); /* one clock cycle at 100 kHz */
	} while (timeout--);
	control = readl(&twsi->control);
	if (stop_status != MVTWSI_STATUS_IDLE)
		if (status == 0)
			status = MVTWSI_ERROR(
				MVTWSI_ERROR_TIMEOUT,
				control, status, MVTWSI_STATUS_IDLE);
	return status;
}

/*
 * Ugly formula to convert m and n values to a frequency comes from
 * TWSI specifications
 */

#define TWSI_FREQUENCY(m, n) \
	(CONFIG_SYS_TCLK / (10 * (m + 1) * (1 << n)))

/*
 * Reset controller.
 * Controller reset also resets the baud rate and slave address, so
 * they must be re-established afterwards.
 */
static void twsi_reset(struct i2c_adapter *adap)
{
	/* ensure controller will be enabled by any twsi*() function */
	twsi_control_flags = MVTWSI_CONTROL_TWSIEN;
	/* reset controller */
	writel(0, &twsi->soft_reset);
	/* wait 2 ms -- this is what the Marvell LSP does */
	udelay(20000);
}

/*
 * I2C init called by cmd_i2c when doing 'i2c reset'.
 * Sets baud to the highest possible value not exceeding requested one.
 */
static unsigned int twsi_i2c_set_bus_speed(struct i2c_adapter *adap,
					   unsigned int requested_speed)
{
	unsigned int tmp_speed, highest_speed, n, m;
	unsigned int baud = 0x44; /* baudrate at controller reset */

	/* use actual speed to collect progressively higher values */
	highest_speed = 0;
	/* compute m, n setting for highest speed not above requested speed */
	for (n = 0; n < 8; n++) {
		for (m = 0; m < 16; m++) {
			tmp_speed = TWSI_FREQUENCY(m, n);
			if ((tmp_speed <= requested_speed)
			 && (tmp_speed > highest_speed)) {
				highest_speed = tmp_speed;
				baud = (m << 3) | n;
			}
		}
	}
	writel(baud, &twsi->baudrate);
	return 0;
}

static void twsi_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
{
	/* reset controller */
	twsi_reset(adap);
	/* set speed */
	twsi_i2c_set_bus_speed(adap, speed);
	/* set slave address even though we don't use it */
	writel(slaveadd, &twsi->slave_address);
	writel(0, &twsi->xtnd_slave_addr);
	/* assert STOP but don't care for the result */
	(void) twsi_stop(0);
}

/*
 * Begin I2C transaction with expected start status, at given address.
 * Common to i2c_probe, i2c_read and i2c_write.
 * Expected address status will derive from direction bit (bit 0) in addr.
 */
static int i2c_begin(int expected_start_status, u8 addr)
{
	int status, expected_addr_status;

	/* compute expected address status from direction bit in addr */
	if (addr & 1) /* reading */
		expected_addr_status = MVTWSI_STATUS_ADDR_R_ACK;
	else /* writing */
		expected_addr_status = MVTWSI_STATUS_ADDR_W_ACK;
	/* assert START */
	status = twsi_start(expected_start_status);
	/* send out the address if the start went well */
	if (status == 0)
		status = twsi_send(addr, expected_addr_status);
	/* return ok or status of first failure to caller */
	return status;
}

/*
 * I2C probe called by cmd_i2c when doing 'i2c probe'.
 * Begin read, nak data byte, end.
 */
static int twsi_i2c_probe(struct i2c_adapter *adap, uchar chip)
{
	u8 dummy_byte;
	int status;

	/* begin i2c read */
	status = i2c_begin(MVTWSI_STATUS_START, (chip << 1) | 1);
	/* dummy read was accepted: receive byte but NAK it. */
	if (status == 0)
		status = twsi_recv(&dummy_byte);
	/* Stop transaction */
	twsi_stop(0);
	/* return 0 or status of first failure */
	return status;
}

/*
 * I2C read called by cmd_i2c when doing 'i2c read' and by cmd_eeprom.c
 * Begin write, send address byte(s), begin read, receive data bytes, end.
 *
 * NOTE: some EEPROMS want a stop right before the second start, while
 * some will choke if it is there. Deciding which we should do is eeprom
 * stuff, not i2c, but at the moment the APIs won't let us put it in
 * cmd_eeprom, so we have to choose here, and for the moment that'll be
 * a repeated start without a preceding stop.
 */
static int twsi_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
			int alen, uchar *data, int length)
{
	int status;

	/* begin i2c write to send the address bytes */
	status = i2c_begin(MVTWSI_STATUS_START, (chip << 1));
	/* send addr bytes */
	while ((status == 0) && alen--)
		status = twsi_send(addr >> (8*alen),
			MVTWSI_STATUS_DATA_W_ACK);
	/* begin i2c read to receive eeprom data bytes */
	if (status == 0)
		status = i2c_begin(
			MVTWSI_STATUS_REPEATED_START, (chip << 1) | 1);
	/* prepare ACK if at least one byte must be received */
	if (length > 0)
		twsi_control_flags |= MVTWSI_CONTROL_ACK;
	/* now receive actual bytes */
	while ((status == 0) && length--) {
		/* reset NAK if we if no more to read now */
		if (length == 0)
			twsi_control_flags &= ~MVTWSI_CONTROL_ACK;
		/* read current byte */
		status = twsi_recv(data++);
	}
	/* Stop transaction */
	status = twsi_stop(status);
	/* return 0 or status of first failure */
	return status;
}

/*
 * I2C write called by cmd_i2c when doing 'i2c write' and by cmd_eeprom.c
 * Begin write, send address byte(s), send data bytes, end.
 */
static int twsi_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
			int alen, uchar *data, int length)
{
	int status;

	/* begin i2c write to send the eeprom adress bytes then data bytes */
	status = i2c_begin(MVTWSI_STATUS_START, (chip << 1));
	/* send addr bytes */
	while ((status == 0) && alen--)
		status = twsi_send(addr >> (8*alen),
			MVTWSI_STATUS_DATA_W_ACK);
	/* send data bytes */
	while ((status == 0) && (length-- > 0))
		status = twsi_send(*(data++), MVTWSI_STATUS_DATA_W_ACK);
	/* Stop transaction */
	status = twsi_stop(status);
	/* return 0 or status of first failure */
	return status;
}

U_BOOT_I2C_ADAP_COMPLETE(twsi0, twsi_i2c_init, twsi_i2c_probe,
			 twsi_i2c_read, twsi_i2c_write,
			 twsi_i2c_set_bus_speed,
			 CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE, 0)
Commit	Line	Data
4ce5a728	1	/*
306563a7 AA	2	* Driver for the TWSI (i2c) controller found on the Marvell
306563a7 AA	3	* orion5x and kirkwood SoC families.
4ce5a728	4	*
57b4bce9	5	* Author: Albert Aribaud <[email protected]>
306563a7	6	* Copyright (c) 2010 Albert Aribaud.
4ce5a728	7	*
1a459660	8	* SPDX-License-Identifier: GPL-2.0+
4ce5a728	9	*/
306563a7	10
4ce5a728 HS	11	#include <common.h>
4ce5a728 HS	12	#include <i2c.h>
4ce5a728 HS	13	#include <asm/errno.h>
	14	#include <asm/io.h>
	15
306563a7 AA	16	/*
	17	* include a file that will provide CONFIG_I2C_MVTWSI_BASE
	18	* and possibly other settings
	19	*/
4ce5a728	20
306563a7 AA	21	#if defined(CONFIG_ORION5X)
306563a7 AA	22	#include <asm/arch/orion5x.h>
6d5fe560	23	#elif (defined(CONFIG_KIRKWOOD) \|\| defined(CONFIG_ARMADA_XP))
3dc23f78	24	#include <asm/arch/soc.h>
6620377e HG	25	#elif defined(CONFIG_SUNXI)
6620377e HG	26	#include <asm/arch/i2c.h>
306563a7 AA	27	#else
306563a7 AA	28	#error Driver mvtwsi not supported by SoC or board
4ce5a728 HS	29	#endif
4ce5a728 HS	30
306563a7 AA	31	/*
	32	* TWSI register structure
	33	*/
4ce5a728	34
6620377e HG	35	#ifdef CONFIG_SUNXI
	36
	37	struct mvtwsi_registers {
	38	u32 slave_address;
	39	u32 xtnd_slave_addr;
	40	u32 data;
	41	u32 control;
	42	u32 status;
	43	u32 baudrate;
	44	u32 soft_reset;
	45	};
	46
	47	#else
	48
306563a7 AA	49	struct mvtwsi_registers {
	50	u32 slave_address;
	51	u32 data;
	52	u32 control;
	53	union {
	54	u32 status; /* when reading */
	55	u32 baudrate; /* when writing */
	56	};
	57	u32 xtnd_slave_addr;
	58	u32 reserved[2];
	59	u32 soft_reset;
4ce5a728 HS	60	};
4ce5a728 HS	61
6620377e HG	62	#endif
6620377e HG	63
306563a7 AA	64	/*
	65	* Control register fields
	66	*/
4ce5a728	67
306563a7 AA	68	#define MVTWSI_CONTROL_ACK 0x00000004
	69	#define MVTWSI_CONTROL_IFLG 0x00000008
	70	#define MVTWSI_CONTROL_STOP 0x00000010
	71	#define MVTWSI_CONTROL_START 0x00000020
	72	#define MVTWSI_CONTROL_TWSIEN 0x00000040
	73	#define MVTWSI_CONTROL_INTEN 0x00000080
4ce5a728	74
306563a7 AA	75	/*
	76	* Status register values -- only those expected in normal master
	77	* operation on non-10-bit-address devices; whatever status we don't
	78	* expect in nominal conditions (bus errors, arbitration losses,
	79	* missing ACKs...) we just pass back to the caller as an error
	80	* code.
	81	*/
4ce5a728	82
306563a7 AA	83	#define MVTWSI_STATUS_START 0x08
	84	#define MVTWSI_STATUS_REPEATED_START 0x10
	85	#define MVTWSI_STATUS_ADDR_W_ACK 0x18
	86	#define MVTWSI_STATUS_DATA_W_ACK 0x28
	87	#define MVTWSI_STATUS_ADDR_R_ACK 0x40
	88	#define MVTWSI_STATUS_ADDR_R_NAK 0x48
	89	#define MVTWSI_STATUS_DATA_R_ACK 0x50
	90	#define MVTWSI_STATUS_DATA_R_NAK 0x58
	91	#define MVTWSI_STATUS_IDLE 0xF8
	92
	93	/*
	94	* The single instance of the controller we'll be dealing with
	95	*/
4ce5a728	96
306563a7 AA	97	static struct mvtwsi_registers *twsi =
306563a7 AA	98	(struct mvtwsi_registers *) CONFIG_I2C_MVTWSI_BASE;
4ce5a728 HS	99
4ce5a728 HS	100	/*
306563a7 AA	101	* Returned statuses are 0 for success and nonzero otherwise.
	102	* Currently, cmd_i2c and cmd_eeprom do not interpret an error status.
	103	* Thus to ease debugging, the return status contains some debug info:
	104	* - bits 31..24 are error class: 1 is timeout, 2 is 'status mismatch'.
	105	* - bits 23..16 are the last value of the control register.
	106	* - bits 15..8 are the last value of the status register.
	107	* - bits 7..0 are the expected value of the status register.
4ce5a728 HS	108	*/
4ce5a728 HS	109
306563a7 AA	110	#define MVTWSI_ERROR_WRONG_STATUS 0x01
306563a7 AA	111	#define MVTWSI_ERROR_TIMEOUT 0x02
4ce5a728	112
306563a7 AA	113	#define MVTWSI_ERROR(ec, lc, ls, es) (((ec << 24) & 0xFF000000) \| \
306563a7 AA	114	((lc << 16) & 0x00FF0000) \| ((ls<<8) & 0x0000FF00) \| (es & 0xFF))
4ce5a728	115
306563a7 AA	116	/*
	117	* Wait for IFLG to raise, or return 'timeout'; then if status is as expected,
	118	* return 0 (ok) or return 'wrong status'.
	119	*/
	120	static int twsi_wait(int expected_status)
	121	{
	122	int control, status;
	123	int timeout = 1000;
	124
	125	do {
	126	control = readl(&twsi->control);
	127	if (control & MVTWSI_CONTROL_IFLG) {
	128	status = readl(&twsi->status);
	129	if (status == expected_status)
	130	return 0;
	131	else
	132	return MVTWSI_ERROR(
	133	MVTWSI_ERROR_WRONG_STATUS,
	134	control, status, expected_status);
4ce5a728	135	}
306563a7 AA	136	udelay(10); /* one clock cycle at 100 kHz */
	137	} while (timeout--);
	138	status = readl(&twsi->status);
	139	return MVTWSI_ERROR(
	140	MVTWSI_ERROR_TIMEOUT, control, status, expected_status);
4ce5a728 HS	141	}
4ce5a728 HS	142
306563a7 AA	143	/*
	144	* These flags are ORed to any write to the control register
	145	* They allow global setting of TWSIEN and ACK.
	146	* By default none are set.
	147	* twsi_start() sets TWSIEN (in case the controller was disabled)
	148	* twsi_recv() sets ACK or resets it depending on expected status.
	149	*/
	150	static u8 twsi_control_flags = MVTWSI_CONTROL_TWSIEN;
	151
	152	/*
	153	* Assert the START condition, either in a single I2C transaction
	154	* or inside back-to-back ones (repeated starts).
	155	*/
	156	static int twsi_start(int expected_status)
4ce5a728	157	{
306563a7 AA	158	/* globally set TWSIEN in case it was not */
	159	twsi_control_flags \|= MVTWSI_CONTROL_TWSIEN;
	160	/* assert START */
	161	writel(twsi_control_flags \| MVTWSI_CONTROL_START, &twsi->control);
	162	/* wait for controller to process START */
	163	return twsi_wait(expected_status);
4ce5a728 HS	164	}
4ce5a728 HS	165
306563a7 AA	166	/*
	167	* Send a byte (i2c address or data).
	168	*/
	169	static int twsi_send(u8 byte, int expected_status)
4ce5a728	170	{
306563a7 AA	171	/* put byte in data register for sending */
	172	writel(byte, &twsi->data);
	173	/* clear any pending interrupt -- that'll cause sending */
	174	writel(twsi_control_flags, &twsi->control);
	175	/* wait for controller to receive byte and check ACK */
	176	return twsi_wait(expected_status);
4ce5a728 HS	177	}
4ce5a728 HS	178
306563a7 AA	179	/*
	180	* Receive a byte.
	181	* Global mvtwsi_control_flags variable says if we should ack or nak.
	182	*/
	183	static int twsi_recv(u8 *byte)
4ce5a728	184	{
306563a7 AA	185	int expected_status, status;
	186
	187	/* compute expected status based on ACK bit in global control flags */
	188	if (twsi_control_flags & MVTWSI_CONTROL_ACK)
	189	expected_status = MVTWSI_STATUS_DATA_R_ACK;
	190	else
	191	expected_status = MVTWSI_STATUS_DATA_R_NAK;
	192	/* acknowledge previous state and launch receive */
	193	writel(twsi_control_flags, &twsi->control);
	194	/* wait for controller to receive byte and assert ACK or NAK */
	195	status = twsi_wait(expected_status);
	196	/* if we did receive expected byte then store it */
	197	if (status == 0)
	198	*byte = readl(&twsi->data);
	199	/* return status */
	200	return status;
4ce5a728 HS	201	}
4ce5a728 HS	202
306563a7 AA	203	/*
	204	* Assert the STOP condition.
	205	* This is also used to force the bus back in idle (SDA=SCL=1).
	206	*/
	207	static int twsi_stop(int status)
4ce5a728	208	{
306563a7 AA	209	int control, stop_status;
	210	int timeout = 1000;
	211
	212	/* assert STOP */
	213	control = MVTWSI_CONTROL_TWSIEN \| MVTWSI_CONTROL_STOP;
	214	writel(control, &twsi->control);
	215	/* wait for IDLE; IFLG won't rise so twsi_wait() is no use. */
	216	do {
	217	stop_status = readl(&twsi->status);
	218	if (stop_status == MVTWSI_STATUS_IDLE)
	219	break;
	220	udelay(10); /* one clock cycle at 100 kHz */
	221	} while (timeout--);
	222	control = readl(&twsi->control);
	223	if (stop_status != MVTWSI_STATUS_IDLE)
	224	if (status == 0)
	225	status = MVTWSI_ERROR(
	226	MVTWSI_ERROR_TIMEOUT,
	227	control, status, MVTWSI_STATUS_IDLE);
	228	return status;
4ce5a728 HS	229	}
4ce5a728 HS	230
306563a7 AA	231	/*
	232	* Ugly formula to convert m and n values to a frequency comes from
	233	* TWSI specifications
	234	*/
4ce5a728	235
306563a7	236	#define TWSI_FREQUENCY(m, n) \
fab356a0	237	(CONFIG_SYS_TCLK / (10 * (m + 1) * (1 << n)))
306563a7	238
306563a7 AA	239	/*
306563a7 AA	240	* Reset controller.
306563a7	241	* Controller reset also resets the baud rate and slave address, so
0db2bbdc	242	* they must be re-established afterwards.
306563a7	243	*/
0db2bbdc	244	static void twsi_reset(struct i2c_adapter *adap)
306563a7 AA	245	{
	246	/* ensure controller will be enabled by any twsi() function /
	247	twsi_control_flags = MVTWSI_CONTROL_TWSIEN;
	248	/* reset controller */
	249	writel(0, &twsi->soft_reset);
	250	/* wait 2 ms -- this is what the Marvell LSP does */
	251	udelay(20000);
4ce5a728 HS	252	}
4ce5a728 HS	253
306563a7 AA	254	/*
	255	* I2C init called by cmd_i2c when doing 'i2c reset'.
	256	* Sets baud to the highest possible value not exceeding requested one.
	257	*/
0db2bbdc HG	258	static unsigned int twsi_i2c_set_bus_speed(struct i2c_adapter *adap,
0db2bbdc HG	259	unsigned int requested_speed)
4ce5a728	260	{
0db2bbdc HG	261	unsigned int tmp_speed, highest_speed, n, m;
0db2bbdc HG	262	unsigned int baud = 0x44; /* baudrate at controller reset */
306563a7 AA	263
	264	/* use actual speed to collect progressively higher values */
	265	highest_speed = 0;
	266	/* compute m, n setting for highest speed not above requested speed */
	267	for (n = 0; n < 8; n++) {
	268	for (m = 0; m < 16; m++) {
	269	tmp_speed = TWSI_FREQUENCY(m, n);
	270	if ((tmp_speed <= requested_speed)
	271	&& (tmp_speed > highest_speed)) {
	272	highest_speed = tmp_speed;
	273	baud = (m << 3) \| n;
	274	}
	275	}
4ce5a728	276	}
0db2bbdc HG	277	writel(baud, &twsi->baudrate);
	278	return 0;
	279	}
	280
	281	static void twsi_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
	282	{
306563a7	283	/* reset controller */
0db2bbdc HG	284	twsi_reset(adap);
	285	/* set speed */
	286	twsi_i2c_set_bus_speed(adap, speed);
	287	/* set slave address even though we don't use it */
	288	writel(slaveadd, &twsi->slave_address);
	289	writel(0, &twsi->xtnd_slave_addr);
	290	/* assert STOP but don't care for the result */
	291	(void) twsi_stop(0);
4ce5a728 HS	292	}
4ce5a728 HS	293
306563a7 AA	294	/*
	295	* Begin I2C transaction with expected start status, at given address.
	296	* Common to i2c_probe, i2c_read and i2c_write.
	297	* Expected address status will derive from direction bit (bit 0) in addr.
	298	*/
	299	static int i2c_begin(int expected_start_status, u8 addr)
4ce5a728	300	{
306563a7 AA	301	int status, expected_addr_status;
	302
	303	/* compute expected address status from direction bit in addr */
	304	if (addr & 1) /* reading */
	305	expected_addr_status = MVTWSI_STATUS_ADDR_R_ACK;
	306	else /* writing */
	307	expected_addr_status = MVTWSI_STATUS_ADDR_W_ACK;
	308	/* assert START */
	309	status = twsi_start(expected_start_status);
	310	/* send out the address if the start went well */
	311	if (status == 0)
	312	status = twsi_send(addr, expected_addr_status);
	313	/* return ok or status of first failure to caller */
	314	return status;
4ce5a728 HS	315	}
4ce5a728 HS	316
306563a7 AA	317	/*
	318	* I2C probe called by cmd_i2c when doing 'i2c probe'.
	319	* Begin read, nak data byte, end.
	320	*/
0db2bbdc	321	static int twsi_i2c_probe(struct i2c_adapter *adap, uchar chip)
4ce5a728	322	{
306563a7 AA	323	u8 dummy_byte;
	324	int status;
	325
	326	/* begin i2c read */
	327	status = i2c_begin(MVTWSI_STATUS_START, (chip << 1) \| 1);
	328	/* dummy read was accepted: receive byte but NAK it. */
	329	if (status == 0)
	330	status = twsi_recv(&dummy_byte);
	331	/* Stop transaction */
	332	twsi_stop(0);
	333	/* return 0 or status of first failure */
	334	return status;
4ce5a728 HS	335	}
4ce5a728 HS	336
306563a7 AA	337	/*
	338	* I2C read called by cmd_i2c when doing 'i2c read' and by cmd_eeprom.c
	339	* Begin write, send address byte(s), begin read, receive data bytes, end.
	340	*
	341	* NOTE: some EEPROMS want a stop right before the second start, while
	342	* some will choke if it is there. Deciding which we should do is eeprom
	343	* stuff, not i2c, but at the moment the APIs won't let us put it in
	344	* cmd_eeprom, so we have to choose here, and for the moment that'll be
	345	* a repeated start without a preceding stop.
	346	*/
0db2bbdc HG	347	static int twsi_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
0db2bbdc HG	348	int alen, uchar *data, int length)
4ce5a728	349	{
306563a7 AA	350	int status;
	351
	352	/* begin i2c write to send the address bytes */
0db2bbdc	353	status = i2c_begin(MVTWSI_STATUS_START, (chip << 1));
306563a7 AA	354	/* send addr bytes */
	355	while ((status == 0) && alen--)
	356	status = twsi_send(addr >> (8*alen),
	357	MVTWSI_STATUS_DATA_W_ACK);
	358	/* begin i2c read to receive eeprom data bytes */
	359	if (status == 0)
	360	status = i2c_begin(
0db2bbdc	361	MVTWSI_STATUS_REPEATED_START, (chip << 1) \| 1);
306563a7 AA	362	/* prepare ACK if at least one byte must be received */
	363	if (length > 0)
	364	twsi_control_flags \|= MVTWSI_CONTROL_ACK;
	365	/* now receive actual bytes */
	366	while ((status == 0) && length--) {
	367	/* reset NAK if we if no more to read now */
	368	if (length == 0)
	369	twsi_control_flags &= ~MVTWSI_CONTROL_ACK;
	370	/* read current byte */
	371	status = twsi_recv(data++);
	372	}
	373	/* Stop transaction */
	374	status = twsi_stop(status);
	375	/* return 0 or status of first failure */
	376	return status;
4ce5a728 HS	377	}
4ce5a728 HS	378
306563a7 AA	379	/*
	380	* I2C write called by cmd_i2c when doing 'i2c write' and by cmd_eeprom.c
	381	* Begin write, send address byte(s), send data bytes, end.
	382	*/
0db2bbdc HG	383	static int twsi_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
0db2bbdc HG	384	int alen, uchar *data, int length)
4ce5a728	385	{
306563a7 AA	386	int status;
	387
	388	/* begin i2c write to send the eeprom adress bytes then data bytes */
0db2bbdc	389	status = i2c_begin(MVTWSI_STATUS_START, (chip << 1));
306563a7 AA	390	/* send addr bytes */
	391	while ((status == 0) && alen--)
	392	status = twsi_send(addr >> (8*alen),
	393	MVTWSI_STATUS_DATA_W_ACK);
	394	/* send data bytes */
	395	while ((status == 0) && (length-- > 0))
	396	status = twsi_send(*(data++), MVTWSI_STATUS_DATA_W_ACK);
	397	/* Stop transaction */
	398	status = twsi_stop(status);
	399	/* return 0 or status of first failure */
	400	return status;
4ce5a728 HS	401	}
4ce5a728 HS	402
0db2bbdc HG	403	U_BOOT_I2C_ADAP_COMPLETE(twsi0, twsi_i2c_init, twsi_i2c_probe,
	404	twsi_i2c_read, twsi_i2c_write,
	405	twsi_i2c_set_bus_speed,
	406	CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE, 0)