xref: /openbmc/u-boot/drivers/i2c/mv_i2c.c (revision 83d290c56fab2d38cd1ab4c4cc7099559c1d5046)

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2000
 * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
 *
 * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <mgroeger@sysgo.de>
 *
 * (C) Copyright 2003 Pengutronix e.K.
 * Robert Schwebel <r.schwebel@pengutronix.de>
 *
 * (C) Copyright 2011 Marvell Inc.
 * Lei Wen <leiwen@marvell.com>
 *
 * Back ported to the 8xx platform (from the 8260 platform) by
 * Murray.Jensen@cmst.csiro.au, 27-Jan-01.
 */

#include <common.h>
#include <dm.h>
#include <i2c.h>
#include <asm/io.h>
#include "mv_i2c.h"

/* All transfers are described by this data structure */
struct mv_i2c_msg {
	u8 condition;
	u8 acknack;
	u8 direction;
	u8 data;
};

#ifdef CONFIG_ARMADA_3700
/* Armada 3700 has no padding between the registers */
struct mv_i2c {
	u32 ibmr;
	u32 idbr;
	u32 icr;
	u32 isr;
	u32 isar;
};
#else
struct mv_i2c {
	u32 ibmr;
	u32 pad0;
	u32 idbr;
	u32 pad1;
	u32 icr;
	u32 pad2;
	u32 isr;
	u32 pad3;
	u32 isar;
};
#endif

/*
 * Dummy implementation that can be overwritten by a board
 * specific function
 */
__weak void i2c_clk_enable(void)
{
}

/*
 * i2c_reset: - reset the host controller
 *
 */
static void i2c_reset(struct mv_i2c *base)
{
	u32 icr_mode;

	/* Save bus mode (standard or fast speed) for later use */
	icr_mode = readl(&base->icr) & ICR_MODE_MASK;
	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */
	writel(readl(&base->icr) | ICR_UR, &base->icr);	  /* reset the unit */
	udelay(100);
	writel(readl(&base->icr) & ~ICR_IUE, &base->icr); /* disable unit */

	i2c_clk_enable();

	writel(CONFIG_SYS_I2C_SLAVE, &base->isar); /* set our slave address */
	/* set control reg values */
	writel(I2C_ICR_INIT | icr_mode, &base->icr);
	writel(I2C_ISR_INIT, &base->isr); /* set clear interrupt bits */
	writel(readl(&base->icr) | ICR_IUE, &base->icr); /* enable unit */
	udelay(100);
}

/*
 * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
 *	                  are set and cleared
 *
 * @return: 1 in case of success, 0 means timeout (no match within 10 ms).
 */
static int i2c_isr_set_cleared(struct mv_i2c *base, unsigned long set_mask,
			       unsigned long cleared_mask)
{
	int timeout = 1000, isr;

	do {
		isr = readl(&base->isr);
		udelay(10);
		if (timeout-- < 0)
			return 0;
	} while (((isr & set_mask) != set_mask)
		|| ((isr & cleared_mask) != 0));

	return 1;
}

/*
 * i2c_transfer: - Transfer one byte over the i2c bus
 *
 * This function can tranfer a byte over the i2c bus in both directions.
 * It is used by the public API functions.
 *
 * @return:  0: transfer successful
 *          -1: message is empty
 *          -2: transmit timeout
 *          -3: ACK missing
 *          -4: receive timeout
 *          -5: illegal parameters
 *          -6: bus is busy and couldn't be aquired
 */
static int i2c_transfer(struct mv_i2c *base, struct mv_i2c_msg *msg)
{
	int ret;

	if (!msg)
		goto transfer_error_msg_empty;

	switch (msg->direction) {
	case I2C_WRITE:
		/* check if bus is not busy */
		if (!i2c_isr_set_cleared(base, 0, ISR_IBB))
			goto transfer_error_bus_busy;

		/* start transmission */
		writel(readl(&base->icr) & ~ICR_START, &base->icr);
		writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
		writel(msg->data, &base->idbr);
		if (msg->condition == I2C_COND_START)
			writel(readl(&base->icr) | ICR_START, &base->icr);
		if (msg->condition == I2C_COND_STOP)
			writel(readl(&base->icr) | ICR_STOP, &base->icr);
		if (msg->acknack == I2C_ACKNAK_SENDNAK)
			writel(readl(&base->icr) | ICR_ACKNAK, &base->icr);
		if (msg->acknack == I2C_ACKNAK_SENDACK)
			writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
		writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
		writel(readl(&base->icr) | ICR_TB, &base->icr);

		/* transmit register empty? */
		if (!i2c_isr_set_cleared(base, ISR_ITE, 0))
			goto transfer_error_transmit_timeout;

		/* clear 'transmit empty' state */
		writel(readl(&base->isr) | ISR_ITE, &base->isr);

		/* wait for ACK from slave */
		if (msg->acknack == I2C_ACKNAK_WAITACK)
			if (!i2c_isr_set_cleared(base, 0, ISR_ACKNAK))
				goto transfer_error_ack_missing;
		break;

	case I2C_READ:

		/* check if bus is not busy */
		if (!i2c_isr_set_cleared(base, 0, ISR_IBB))
			goto transfer_error_bus_busy;

		/* start receive */
		writel(readl(&base->icr) & ~ICR_START, &base->icr);
		writel(readl(&base->icr) & ~ICR_STOP, &base->icr);
		if (msg->condition == I2C_COND_START)
			writel(readl(&base->icr) | ICR_START, &base->icr);
		if (msg->condition == I2C_COND_STOP)
			writel(readl(&base->icr) | ICR_STOP, &base->icr);
		if (msg->acknack == I2C_ACKNAK_SENDNAK)
			writel(readl(&base->icr) | ICR_ACKNAK, &base->icr);
		if (msg->acknack == I2C_ACKNAK_SENDACK)
			writel(readl(&base->icr) & ~ICR_ACKNAK, &base->icr);
		writel(readl(&base->icr) & ~ICR_ALDIE, &base->icr);
		writel(readl(&base->icr) | ICR_TB, &base->icr);

		/* receive register full? */
		if (!i2c_isr_set_cleared(base, ISR_IRF, 0))
			goto transfer_error_receive_timeout;

		msg->data = readl(&base->idbr);

		/* clear 'receive empty' state */
		writel(readl(&base->isr) | ISR_IRF, &base->isr);
		break;
	default:
		goto transfer_error_illegal_param;
	}

	return 0;

transfer_error_msg_empty:
	debug("i2c_transfer: error: 'msg' is empty\n");
	ret = -1;
	goto i2c_transfer_finish;

transfer_error_transmit_timeout:
	debug("i2c_transfer: error: transmit timeout\n");
	ret = -2;
	goto i2c_transfer_finish;

transfer_error_ack_missing:
	debug("i2c_transfer: error: ACK missing\n");
	ret = -3;
	goto i2c_transfer_finish;

transfer_error_receive_timeout:
	debug("i2c_transfer: error: receive timeout\n");
	ret = -4;
	goto i2c_transfer_finish;

transfer_error_illegal_param:
	debug("i2c_transfer: error: illegal parameters\n");
	ret = -5;
	goto i2c_transfer_finish;

transfer_error_bus_busy:
	debug("i2c_transfer: error: bus is busy\n");
	ret = -6;
	goto i2c_transfer_finish;

i2c_transfer_finish:
	debug("i2c_transfer: ISR: 0x%04x\n", readl(&base->isr));
	i2c_reset(base);
	return ret;
}

static int __i2c_read(struct mv_i2c *base, uchar chip, u8 *addr, int alen,
		      uchar *buffer, int len)
{
	struct mv_i2c_msg msg;

	debug("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
	      "len=0x%02x)\n", chip, *addr, alen, len);

	if (len == 0) {
		printf("reading zero byte is invalid\n");
		return -EINVAL;
	}

	i2c_reset(base);

	/* dummy chip address write */
	debug("i2c_read: dummy chip address write\n");
	msg.condition = I2C_COND_START;
	msg.acknack   = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = (chip << 1);
	msg.data &= 0xFE;
	if (i2c_transfer(base, &msg))
		return -1;

	/*
	 * send memory address bytes;
	 * alen defines how much bytes we have to send.
	 */
	while (--alen >= 0) {
		debug("i2c_read: send address byte %02x (alen=%d)\n",
		      *addr, alen);
		msg.condition = I2C_COND_NORMAL;
		msg.acknack   = I2C_ACKNAK_WAITACK;
		msg.direction = I2C_WRITE;
		msg.data      = addr[alen];
		if (i2c_transfer(base, &msg))
			return -1;
	}

	/* start read sequence */
	debug("i2c_read: start read sequence\n");
	msg.condition = I2C_COND_START;
	msg.acknack   = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data      = (chip << 1);
	msg.data     |= 0x01;
	if (i2c_transfer(base, &msg))
		return -1;

	/* read bytes; send NACK at last byte */
	while (len--) {
		if (len == 0) {
			msg.condition = I2C_COND_STOP;
			msg.acknack   = I2C_ACKNAK_SENDNAK;
		} else {
			msg.condition = I2C_COND_NORMAL;
			msg.acknack   = I2C_ACKNAK_SENDACK;
		}

		msg.direction = I2C_READ;
		msg.data      = 0x00;
		if (i2c_transfer(base, &msg))
			return -1;

		*buffer = msg.data;
		debug("i2c_read: reading byte (%p)=0x%02x\n",
		      buffer, *buffer);
		buffer++;
	}

	i2c_reset(base);

	return 0;
}

static int __i2c_write(struct mv_i2c *base, uchar chip, u8 *addr, int alen,
		       uchar *buffer, int len)
{
	struct mv_i2c_msg msg;

	debug("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, "
	      "len=0x%02x)\n", chip, *addr, alen, len);

	i2c_reset(base);

	/* chip address write */
	debug("i2c_write: chip address write\n");
	msg.condition = I2C_COND_START;
	msg.acknack   = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data = (chip << 1);
	msg.data &= 0xFE;
	if (i2c_transfer(base, &msg))
		return -1;

	/*
	 * send memory address bytes;
	 * alen defines how much bytes we have to send.
	 */
	while (--alen >= 0) {
		debug("i2c_read: send address byte %02x (alen=%d)\n",
		      *addr, alen);
		msg.condition = I2C_COND_NORMAL;
		msg.acknack   = I2C_ACKNAK_WAITACK;
		msg.direction = I2C_WRITE;
		msg.data      = addr[alen];
		if (i2c_transfer(base, &msg))
			return -1;
	}

	/* write bytes; send NACK at last byte */
	while (len--) {
		debug("i2c_write: writing byte (%p)=0x%02x\n",
		      buffer, *buffer);

		if (len == 0)
			msg.condition = I2C_COND_STOP;
		else
			msg.condition = I2C_COND_NORMAL;

		msg.acknack   = I2C_ACKNAK_WAITACK;
		msg.direction = I2C_WRITE;
		msg.data      = *(buffer++);

		if (i2c_transfer(base, &msg))
			return -1;
	}

	i2c_reset(base);

	return 0;
}

#ifndef CONFIG_DM_I2C

static struct mv_i2c *base_glob;

static void i2c_board_init(struct mv_i2c *base)
{
#ifdef CONFIG_SYS_I2C_INIT_BOARD
	u32 icr;
	/*
	 * call board specific i2c bus reset routine before accessing the
	 * environment, which might be in a chip on that bus. For details
	 * about this problem see doc/I2C_Edge_Conditions.
	 *
	 * disable I2C controller first, otherwhise it thinks we want to
	 * talk to the slave port...
	 */
	icr = readl(&base->icr);
	writel(readl(&base->icr) & ~(ICR_SCLE | ICR_IUE), &base->icr);

	i2c_init_board();

	writel(icr, &base->icr);
#endif
}

#ifdef CONFIG_I2C_MULTI_BUS
static unsigned long i2c_regs[CONFIG_MV_I2C_NUM] = CONFIG_MV_I2C_REG;
static unsigned int bus_initialized[CONFIG_MV_I2C_NUM];
static unsigned int current_bus;

int i2c_set_bus_num(unsigned int bus)
{
	if ((bus < 0) || (bus >= CONFIG_MV_I2C_NUM)) {
		printf("Bad bus: %d\n", bus);
		return -1;
	}

	base_glob = (struct mv_i2c *)i2c_regs[bus];
	current_bus = bus;

	if (!bus_initialized[current_bus]) {
		i2c_board_init(base_glob);
		bus_initialized[current_bus] = 1;
	}

	return 0;
}

unsigned int i2c_get_bus_num(void)
{
	return current_bus;
}
#endif

/* API Functions */
void i2c_init(int speed, int slaveaddr)
{
	u32 val;

#ifdef CONFIG_I2C_MULTI_BUS
	current_bus = 0;
	base_glob = (struct mv_i2c *)i2c_regs[current_bus];
#else
	base_glob = (struct mv_i2c *)CONFIG_MV_I2C_REG;
#endif

	if (speed > 100000)
		val = ICR_FM;
	else
		val = ICR_SM;
	clrsetbits_le32(&base_glob->icr, ICR_MODE_MASK, val);

	i2c_board_init(base_glob);
}

static int __i2c_probe_chip(struct mv_i2c *base, uchar chip)
{
	struct mv_i2c_msg msg;

	i2c_reset(base);

	msg.condition = I2C_COND_START;
	msg.acknack   = I2C_ACKNAK_WAITACK;
	msg.direction = I2C_WRITE;
	msg.data      = (chip << 1) + 1;
	if (i2c_transfer(base, &msg))
		return -1;

	msg.condition = I2C_COND_STOP;
	msg.acknack   = I2C_ACKNAK_SENDNAK;
	msg.direction = I2C_READ;
	msg.data      = 0x00;
	if (i2c_transfer(base, &msg))
		return -1;

	return 0;
}

/*
 * i2c_probe: - Test if a chip answers for a given i2c address
 *
 * @chip:	address of the chip which is searched for
 * @return:	0 if a chip was found, -1 otherwhise
 */
int i2c_probe(uchar chip)
{
	return __i2c_probe_chip(base_glob, chip);
}

/*
 * i2c_read: - Read multiple bytes from an i2c device
 *
 * The higher level routines take into account that this function is only
 * called with len < page length of the device (see configuration file)
 *
 * @chip:      address of the chip which is to be read
 * @addr:      i2c data address within the chip
 * @alen:      length of the i2c data address (1..2 bytes)
 * @buffer:    where to write the data
 * @len:       how much byte do we want to read
 * @return:    0 in case of success
 */
int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
	u8 addr_bytes[4];

	addr_bytes[0] = (addr >> 0) & 0xFF;
	addr_bytes[1] = (addr >> 8) & 0xFF;
	addr_bytes[2] = (addr >> 16) & 0xFF;
	addr_bytes[3] = (addr >> 24) & 0xFF;

	return __i2c_read(base_glob, chip, addr_bytes, alen, buffer, len);
}

/*
 * i2c_write: -  Write multiple bytes to an i2c device
 *
 * The higher level routines take into account that this function is only
 * called with len < page length of the device (see configuration file)
 *
 * @chip:	address of the chip which is to be written
 * @addr:	i2c data address within the chip
 * @alen:	length of the i2c data address (1..2 bytes)
 * @buffer:	where to find the data to be written
 * @len:	how much byte do we want to read
 * @return:	0 in case of success
 */
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
	u8 addr_bytes[4];

	addr_bytes[0] = (addr >> 0) & 0xFF;
	addr_bytes[1] = (addr >> 8) & 0xFF;
	addr_bytes[2] = (addr >> 16) & 0xFF;
	addr_bytes[3] = (addr >> 24) & 0xFF;

	return __i2c_write(base_glob, chip, addr_bytes, alen, buffer, len);
}

#else /* CONFIG_DM_I2C */

struct mv_i2c_priv {
	struct mv_i2c *base;
};

static int mv_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, int nmsgs)
{
	struct mv_i2c_priv *i2c = dev_get_priv(bus);
	struct i2c_msg *dmsg, *omsg, dummy;

	memset(&dummy, 0, sizeof(struct i2c_msg));

	/*
	 * We expect either two messages (one with an offset and one with the
	 * actual data) or one message (just data or offset/data combined)
	 */
	if (nmsgs > 2 || nmsgs == 0) {
		debug("%s: Only one or two messages are supported.", __func__);
		return -1;
	}

	omsg = nmsgs == 1 ? &dummy : msg;
	dmsg = nmsgs == 1 ? msg : msg + 1;

	if (dmsg->flags & I2C_M_RD)
		return __i2c_read(i2c->base, dmsg->addr, omsg->buf,
				  omsg->len, dmsg->buf, dmsg->len);
	else
		return __i2c_write(i2c->base, dmsg->addr, omsg->buf,
				   omsg->len, dmsg->buf, dmsg->len);
}

static int mv_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
	struct mv_i2c_priv *priv = dev_get_priv(bus);
	u32 val;

	if (speed > 100000)
		val = ICR_FM;
	else
		val = ICR_SM;
	clrsetbits_le32(&priv->base->icr, ICR_MODE_MASK, val);

	return 0;
}

static int mv_i2c_probe(struct udevice *bus)
{
	struct mv_i2c_priv *priv = dev_get_priv(bus);

	priv->base = (void *)devfdt_get_addr_ptr(bus);

	return 0;
}

static const struct dm_i2c_ops mv_i2c_ops = {
	.xfer		= mv_i2c_xfer,
	.set_bus_speed	= mv_i2c_set_bus_speed,
};

static const struct udevice_id mv_i2c_ids[] = {
	{ .compatible = "marvell,armada-3700-i2c" },
	{ }
};

U_BOOT_DRIVER(i2c_mv) = {
	.name	= "i2c_mv",
	.id	= UCLASS_I2C,
	.of_match = mv_i2c_ids,
	.probe	= mv_i2c_probe,
	.priv_auto_alloc_size = sizeof(struct mv_i2c_priv),
	.ops	= &mv_i2c_ops,
};
#endif /* CONFIG_DM_I2C */