[deliverable/linux.git] / drivers / i2c / busses / i2c-ocores.c

/*
 * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
 * (http://www.opencores.org/projects.cgi/web/i2c/overview).
 *
 * Peter Korsgaard <jacmet@sunsite.dk>
 *
 * Support for the GRLIB port of the controller by
 * Andreas Larsson <andreas@gaisler.com>
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2.  This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/i2c-ocores.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/log2.h>

struct ocores_i2c {
	void __iomem *base;
	u32 reg_shift;
	u32 reg_io_width;
	wait_queue_head_t wait;
	struct i2c_adapter adap;
	struct i2c_msg *msg;
	int pos;
	int nmsgs;
	int state; /* see STATE_ */
	struct clk *clk;
	int ip_clock_khz;
	int bus_clock_khz;
	void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value);
	u8 (*getreg)(struct ocores_i2c *i2c, int reg);
};

/* registers */
#define OCI2C_PRELOW		0
#define OCI2C_PREHIGH		1
#define OCI2C_CONTROL		2
#define OCI2C_DATA		3
#define OCI2C_CMD		4 /* write only */
#define OCI2C_STATUS		4 /* read only, same address as OCI2C_CMD */

#define OCI2C_CTRL_IEN		0x40
#define OCI2C_CTRL_EN		0x80

#define OCI2C_CMD_START		0x91
#define OCI2C_CMD_STOP		0x41
#define OCI2C_CMD_READ		0x21
#define OCI2C_CMD_WRITE		0x11
#define OCI2C_CMD_READ_ACK	0x21
#define OCI2C_CMD_READ_NACK	0x29
#define OCI2C_CMD_IACK		0x01

#define OCI2C_STAT_IF		0x01
#define OCI2C_STAT_TIP		0x02
#define OCI2C_STAT_ARBLOST	0x20
#define OCI2C_STAT_BUSY		0x40
#define OCI2C_STAT_NACK		0x80

#define STATE_DONE		0
#define STATE_START		1
#define STATE_WRITE		2
#define STATE_READ		3
#define STATE_ERROR		4

#define TYPE_OCORES		0
#define TYPE_GRLIB		1

static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite8(value, i2c->base + (reg << i2c->reg_shift));
}

static void oc_setreg_16(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite16(value, i2c->base + (reg << i2c->reg_shift));
}

static void oc_setreg_32(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite32(value, i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_8(struct ocores_i2c *i2c, int reg)
{
	return ioread8(i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_16(struct ocores_i2c *i2c, int reg)
{
	return ioread16(i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_32(struct ocores_i2c *i2c, int reg)
{
	return ioread32(i2c->base + (reg << i2c->reg_shift));
}

static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
{
	i2c->setreg(i2c, reg, value);
}

static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
{
	return i2c->getreg(i2c, reg);
}

static void ocores_process(struct ocores_i2c *i2c)
{
	struct i2c_msg *msg = i2c->msg;
	u8 stat = oc_getreg(i2c, OCI2C_STATUS);

	if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
		/* stop has been sent */
		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
		wake_up(&i2c->wait);
		return;
	}

	/* error? */
	if (stat & OCI2C_STAT_ARBLOST) {
		i2c->state = STATE_ERROR;
		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
		return;
	}

	if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
		i2c->state =
			(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;

		if (stat & OCI2C_STAT_NACK) {
			i2c->state = STATE_ERROR;
			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
			return;
		}
	} else
		msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);

	/* end of msg? */
	if (i2c->pos == msg->len) {
		i2c->nmsgs--;
		i2c->msg++;
		i2c->pos = 0;
		msg = i2c->msg;

		if (i2c->nmsgs) {	/* end? */
			/* send start? */
			if (!(msg->flags & I2C_M_NOSTART)) {
				u8 addr = (msg->addr << 1);

				if (msg->flags & I2C_M_RD)
					addr |= 1;

				i2c->state = STATE_START;

				oc_setreg(i2c, OCI2C_DATA, addr);
				oc_setreg(i2c, OCI2C_CMD,  OCI2C_CMD_START);
				return;
			} else
				i2c->state = (msg->flags & I2C_M_RD)
					? STATE_READ : STATE_WRITE;
		} else {
			i2c->state = STATE_DONE;
			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
			return;
		}
	}

	if (i2c->state == STATE_READ) {
		oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
			  OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
	} else {
		oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
	}
}

static irqreturn_t ocores_isr(int irq, void *dev_id)
{
	struct ocores_i2c *i2c = dev_id;

	ocores_process(i2c);

	return IRQ_HANDLED;
}

static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	struct ocores_i2c *i2c = i2c_get_adapdata(adap);

	i2c->msg = msgs;
	i2c->pos = 0;
	i2c->nmsgs = num;
	i2c->state = STATE_START;

	oc_setreg(i2c, OCI2C_DATA,
			(i2c->msg->addr << 1) |
			((i2c->msg->flags & I2C_M_RD) ? 1:0));

	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);

	if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
			       (i2c->state == STATE_DONE), HZ))
		return (i2c->state == STATE_DONE) ? num : -EIO;
	else
		return -ETIMEDOUT;
}

static int ocores_init(struct device *dev, struct ocores_i2c *i2c)
{
	int prescale;
	int diff;
	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

	/* make sure the device is disabled */
	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));

	prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
	prescale = clamp(prescale, 0, 0xffff);

	diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;
	if (abs(diff) > i2c->bus_clock_khz / 10) {
		dev_err(dev,
			"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",
			i2c->ip_clock_khz, i2c->bus_clock_khz);
		return -EINVAL;
	}

	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);

	/* Init the device */
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);

	return 0;
}


static u32 ocores_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static const struct i2c_algorithm ocores_algorithm = {
	.master_xfer = ocores_xfer,
	.functionality = ocores_func,
};

static struct i2c_adapter ocores_adapter = {
	.owner = THIS_MODULE,
	.name = "i2c-ocores",
	.class = I2C_CLASS_DEPRECATED,
	.algo = &ocores_algorithm,
};

static const struct of_device_id ocores_i2c_match[] = {
	{
		.compatible = "opencores,i2c-ocores",
		.data = (void *)TYPE_OCORES,
	},
	{
		.compatible = "aeroflexgaisler,i2cmst",
		.data = (void *)TYPE_GRLIB,
	},
	{},
};
MODULE_DEVICE_TABLE(of, ocores_i2c_match);

#ifdef CONFIG_OF
/* Read and write functions for the GRLIB port of the controller. Registers are
 * 32-bit big endian and the PRELOW and PREHIGH registers are merged into one
 * register. The subsequent registers has their offset decreased accordingly. */
static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg)
{
	u32 rd;
	int rreg = reg;
	if (reg != OCI2C_PRELOW)
		rreg--;
	rd = ioread32be(i2c->base + (rreg << i2c->reg_shift));
	if (reg == OCI2C_PREHIGH)
		return (u8)(rd >> 8);
	else
		return (u8)rd;
}

static void oc_setreg_grlib(struct ocores_i2c *i2c, int reg, u8 value)
{
	u32 curr, wr;
	int rreg = reg;
	if (reg != OCI2C_PRELOW)
		rreg--;
	if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) {
		curr = ioread32be(i2c->base + (rreg << i2c->reg_shift));
		if (reg == OCI2C_PRELOW)
			wr = (curr & 0xff00) | value;
		else
			wr = (((u32)value) << 8) | (curr & 0xff);
	} else {
		wr = value;
	}
	iowrite32be(wr, i2c->base + (rreg << i2c->reg_shift));
}

static int ocores_i2c_of_probe(struct platform_device *pdev,
				struct ocores_i2c *i2c)
{
	struct device_node *np = pdev->dev.of_node;
	const struct of_device_id *match;
	u32 val;
	u32 clock_frequency;
	bool clock_frequency_present;

	if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
		/* no 'reg-shift', check for deprecated 'regstep' */
		if (!of_property_read_u32(np, "regstep", &val)) {
			if (!is_power_of_2(val)) {
				dev_err(&pdev->dev, "invalid regstep %d\n",
					val);
				return -EINVAL;
			}
			i2c->reg_shift = ilog2(val);
			dev_warn(&pdev->dev,
				"regstep property deprecated, use reg-shift\n");
		}
	}

	clock_frequency_present = !of_property_read_u32(np, "clock-frequency",
							&clock_frequency);
	i2c->bus_clock_khz = 100;

	i2c->clk = devm_clk_get(&pdev->dev, NULL);

	if (!IS_ERR(i2c->clk)) {
		int ret = clk_prepare_enable(i2c->clk);

		if (ret) {
			dev_err(&pdev->dev,
				"clk_prepare_enable failed: %d\n", ret);
			return ret;
		}
		i2c->ip_clock_khz = clk_get_rate(i2c->clk) / 1000;
		if (clock_frequency_present)
			i2c->bus_clock_khz = clock_frequency / 1000;
	}

	if (i2c->ip_clock_khz == 0) {
		if (of_property_read_u32(np, "opencores,ip-clock-frequency",
						&val)) {
			if (!clock_frequency_present) {
				dev_err(&pdev->dev,
					"Missing required parameter 'opencores,ip-clock-frequency'\n");
				return -ENODEV;
			}
			i2c->ip_clock_khz = clock_frequency / 1000;
			dev_warn(&pdev->dev,
				 "Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");
		} else {
			i2c->ip_clock_khz = val / 1000;
			if (clock_frequency_present)
				i2c->bus_clock_khz = clock_frequency / 1000;
		}
	}

	of_property_read_u32(pdev->dev.of_node, "reg-io-width",
				&i2c->reg_io_width);

	match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
	if (match && (long)match->data == TYPE_GRLIB) {
		dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n");
		i2c->setreg = oc_setreg_grlib;
		i2c->getreg = oc_getreg_grlib;
	}

	return 0;
}
#else
#define ocores_i2c_of_probe(pdev,i2c) -ENODEV
#endif

static int ocores_i2c_probe(struct platform_device *pdev)
{
	struct ocores_i2c *i2c;
	struct ocores_i2c_platform_data *pdata;
	struct resource *res;
	int irq;
	int ret;
	int i;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
	if (!i2c)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	i2c->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(i2c->base))
		return PTR_ERR(i2c->base);

	pdata = dev_get_platdata(&pdev->dev);
	if (pdata) {
		i2c->reg_shift = pdata->reg_shift;
		i2c->reg_io_width = pdata->reg_io_width;
		i2c->ip_clock_khz = pdata->clock_khz;
		i2c->bus_clock_khz = 100;
	} else {
		ret = ocores_i2c_of_probe(pdev, i2c);
		if (ret)
			return ret;
	}

	if (i2c->reg_io_width == 0)
		i2c->reg_io_width = 1; /* Set to default value */

	if (!i2c->setreg || !i2c->getreg) {
		switch (i2c->reg_io_width) {
		case 1:
			i2c->setreg = oc_setreg_8;
			i2c->getreg = oc_getreg_8;
			break;

		case 2:
			i2c->setreg = oc_setreg_16;
			i2c->getreg = oc_getreg_16;
			break;

		case 4:
			i2c->setreg = oc_setreg_32;
			i2c->getreg = oc_getreg_32;
			break;

		default:
			dev_err(&pdev->dev, "Unsupported I/O width (%d)\n",
				i2c->reg_io_width);
			return -EINVAL;
		}
	}

	ret = ocores_init(&pdev->dev, i2c);
	if (ret)
		return ret;

	init_waitqueue_head(&i2c->wait);
	ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
			       pdev->name, i2c);
	if (ret) {
		dev_err(&pdev->dev, "Cannot claim IRQ\n");
		return ret;
	}

	/* hook up driver to tree */
	platform_set_drvdata(pdev, i2c);
	i2c->adap = ocores_adapter;
	i2c_set_adapdata(&i2c->adap, i2c);
	i2c->adap.dev.parent = &pdev->dev;
	i2c->adap.dev.of_node = pdev->dev.of_node;

	/* add i2c adapter to i2c tree */
	ret = i2c_add_adapter(&i2c->adap);
	if (ret) {
		dev_err(&pdev->dev, "Failed to add adapter\n");
		return ret;
	}

	/* add in known devices to the bus */
	if (pdata) {
		for (i = 0; i < pdata->num_devices; i++)
			i2c_new_device(&i2c->adap, pdata->devices + i);
	}

	return 0;
}

static int ocores_i2c_remove(struct platform_device *pdev)
{
	struct ocores_i2c *i2c = platform_get_drvdata(pdev);

	/* disable i2c logic */
	oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
		  & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));

	/* remove adapter & data */
	i2c_del_adapter(&i2c->adap);

	if (!IS_ERR(i2c->clk))
		clk_disable_unprepare(i2c->clk);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int ocores_i2c_suspend(struct device *dev)
{
	struct ocores_i2c *i2c = dev_get_drvdata(dev);
	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

	/* make sure the device is disabled */
	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));

	if (!IS_ERR(i2c->clk))
		clk_disable_unprepare(i2c->clk);
	return 0;
}

static int ocores_i2c_resume(struct device *dev)
{
	struct ocores_i2c *i2c = dev_get_drvdata(dev);

	if (!IS_ERR(i2c->clk)) {
		unsigned long rate;
		int ret = clk_prepare_enable(i2c->clk);

		if (ret) {
			dev_err(dev,
				"clk_prepare_enable failed: %d\n", ret);
			return ret;
		}
		rate = clk_get_rate(i2c->clk) / 1000;
		if (rate)
			i2c->ip_clock_khz = rate;
	}
	return ocores_init(dev, i2c);
}

static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume);
#define OCORES_I2C_PM	(&ocores_i2c_pm)
#else
#define OCORES_I2C_PM	NULL
#endif

static struct platform_driver ocores_i2c_driver = {
	.probe   = ocores_i2c_probe,
	.remove  = ocores_i2c_remove,
	.driver  = {
		.name = "ocores-i2c",
		.of_match_table = ocores_i2c_match,
		.pm = OCORES_I2C_PM,
	},
};

module_platform_driver(ocores_i2c_driver);

MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
MODULE_DESCRIPTION("OpenCores I2C bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ocores-i2c");
Commit	Line	Data
18f98b1e PK	1	/*
	2	* i2c-ocores.c: I2C bus driver for OpenCores I2C controller
	3	* (http://www.opencores.org/projects.cgi/web/i2c/overview).
	4	*
	5	* Peter Korsgaard <jacmet@sunsite.dk>
	6	*
a000b8c1 AL	7	* Support for the GRLIB port of the controller by
	8	* Andreas Larsson <andreas@gaisler.com>
	9	*
18f98b1e PK	10	* This file is licensed under the terms of the GNU General Public License
	11	* version 2. This program is licensed "as is" without any warranty of any
	12	* kind, whether express or implied.
	13	*/
	14
e961a094	15	#include <linux/clk.h>
84dbf809	16	#include <linux/err.h>
18f98b1e PK	17	#include <linux/kernel.h>
18f98b1e PK	18	#include <linux/module.h>
18f98b1e PK	19	#include <linux/errno.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/i2c.h>
	22	#include <linux/interrupt.h>
	23	#include <linux/wait.h>
	24	#include <linux/i2c-ocores.h>
5a0e3ad6	25	#include <linux/slab.h>
21782180	26	#include <linux/io.h>
8bb986a8	27	#include <linux/log2.h>
18f98b1e PK	28
	29	struct ocores_i2c {
	30	void __iomem *base;
8bb986a8	31	u32 reg_shift;
7326e38f	32	u32 reg_io_width;
18f98b1e PK	33	wait_queue_head_t wait;
	34	struct i2c_adapter adap;
	35	struct i2c_msg *msg;
	36	int pos;
	37	int nmsgs;
	38	int state; /* see STATE_ */
e961a094	39	struct clk *clk;
3a33a854 MF	40	int ip_clock_khz;
3a33a854 MF	41	int bus_clock_khz;
a000b8c1 AL	42	void (setreg)(struct ocores_i2c i2c, int reg, u8 value);
a000b8c1 AL	43	u8 (getreg)(struct ocores_i2c i2c, int reg);
18f98b1e PK	44	};
	45
	46	/* registers */
	47	#define OCI2C_PRELOW 0
	48	#define OCI2C_PREHIGH 1
	49	#define OCI2C_CONTROL 2
	50	#define OCI2C_DATA 3
1ded969f PK	51	#define OCI2C_CMD 4 /* write only */
1ded969f PK	52	#define OCI2C_STATUS 4 /* read only, same address as OCI2C_CMD */
18f98b1e PK	53
	54	#define OCI2C_CTRL_IEN 0x40
	55	#define OCI2C_CTRL_EN 0x80
	56
	57	#define OCI2C_CMD_START 0x91
	58	#define OCI2C_CMD_STOP 0x41
	59	#define OCI2C_CMD_READ 0x21
	60	#define OCI2C_CMD_WRITE 0x11
	61	#define OCI2C_CMD_READ_ACK 0x21
	62	#define OCI2C_CMD_READ_NACK 0x29
	63	#define OCI2C_CMD_IACK 0x01
	64
	65	#define OCI2C_STAT_IF 0x01
	66	#define OCI2C_STAT_TIP 0x02
	67	#define OCI2C_STAT_ARBLOST 0x20
	68	#define OCI2C_STAT_BUSY 0x40
	69	#define OCI2C_STAT_NACK 0x80
	70
	71	#define STATE_DONE 0
	72	#define STATE_START 1
	73	#define STATE_WRITE 2
	74	#define STATE_READ 3
	75	#define STATE_ERROR 4
	76
a000b8c1 AL	77	#define TYPE_OCORES 0
	78	#define TYPE_GRLIB 1
	79
	80	static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
18f98b1e	81	{
a000b8c1 AL	82	iowrite8(value, i2c->base + (reg << i2c->reg_shift));
	83	}
	84
	85	static void oc_setreg_16(struct ocores_i2c *i2c, int reg, u8 value)
	86	{
	87	iowrite16(value, i2c->base + (reg << i2c->reg_shift));
	88	}
	89
	90	static void oc_setreg_32(struct ocores_i2c *i2c, int reg, u8 value)
	91	{
	92	iowrite32(value, i2c->base + (reg << i2c->reg_shift));
	93	}
	94
	95	static inline u8 oc_getreg_8(struct ocores_i2c *i2c, int reg)
	96	{
	97	return ioread8(i2c->base + (reg << i2c->reg_shift));
	98	}
	99
	100	static inline u8 oc_getreg_16(struct ocores_i2c *i2c, int reg)
	101	{
	102	return ioread16(i2c->base + (reg << i2c->reg_shift));
	103	}
	104
	105	static inline u8 oc_getreg_32(struct ocores_i2c *i2c, int reg)
	106	{
	107	return ioread32(i2c->base + (reg << i2c->reg_shift));
	108	}
	109
18f98b1e PK	110	static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
18f98b1e PK	111	{
a000b8c1	112	i2c->setreg(i2c, reg, value);
18f98b1e PK	113	}
	114
	115	static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
	116	{
a000b8c1	117	return i2c->getreg(i2c, reg);
18f98b1e PK	118	}
	119
	120	static void ocores_process(struct ocores_i2c *i2c)
	121	{
	122	struct i2c_msg *msg = i2c->msg;
	123	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
	124
	125	if ((i2c->state == STATE_DONE) \|\| (i2c->state == STATE_ERROR)) {
	126	/* stop has been sent */
	127	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
	128	wake_up(&i2c->wait);
	129	return;
	130	}
	131
	132	/* error? */
	133	if (stat & OCI2C_STAT_ARBLOST) {
	134	i2c->state = STATE_ERROR;
	135	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
	136	return;
	137	}
	138
	139	if ((i2c->state == STATE_START) \|\| (i2c->state == STATE_WRITE)) {
	140	i2c->state =
	141	(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
	142
	143	if (stat & OCI2C_STAT_NACK) {
	144	i2c->state = STATE_ERROR;
	145	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
	146	return;
	147	}
	148	} else
	149	msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
	150
	151	/* end of msg? */
	152	if (i2c->pos == msg->len) {
	153	i2c->nmsgs--;
	154	i2c->msg++;
	155	i2c->pos = 0;
	156	msg = i2c->msg;
	157
	158	if (i2c->nmsgs) { /* end? */
	159	/* send start? */
	160	if (!(msg->flags & I2C_M_NOSTART)) {
	161	u8 addr = (msg->addr << 1);
	162
	163	if (msg->flags & I2C_M_RD)
	164	addr \|= 1;
	165
	166	i2c->state = STATE_START;
	167
	168	oc_setreg(i2c, OCI2C_DATA, addr);
	169	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
	170	return;
	171	} else
	172	i2c->state = (msg->flags & I2C_M_RD)
	173	? STATE_READ : STATE_WRITE;
	174	} else {
	175	i2c->state = STATE_DONE;
	176	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
	177	return;
	178	}
	179	}
	180
	181	if (i2c->state == STATE_READ) {
182	oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
183	OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
184	} else {
185	oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
186	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
187	}
188	}
189
7d12e780	190	static irqreturn_t ocores_isr(int irq, void *dev_id)
18f98b1e PK	191	{
	192	struct ocores_i2c *i2c = dev_id;
	193
	194	ocores_process(i2c);
	195
	196	return IRQ_HANDLED;
	197	}
	198
	199	static int ocores_xfer(struct i2c_adapter adap, struct i2c_msg msgs, int num)
	200	{
	201	struct ocores_i2c *i2c = i2c_get_adapdata(adap);
	202
	203	i2c->msg = msgs;
	204	i2c->pos = 0;
	205	i2c->nmsgs = num;
	206	i2c->state = STATE_START;
	207
	208	oc_setreg(i2c, OCI2C_DATA,
	209	(i2c->msg->addr << 1) \|
	210	((i2c->msg->flags & I2C_M_RD) ? 1:0));
	211
	212	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
	213
	214	if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) \|\|
	215	(i2c->state == STATE_DONE), HZ))
	216	return (i2c->state == STATE_DONE) ? num : -EIO;
	217	else
	218	return -ETIMEDOUT;
	219	}
	220
3a33a854	221	static int ocores_init(struct device dev, struct ocores_i2c i2c)
18f98b1e PK	222	{
18f98b1e PK	223	int prescale;
3a33a854	224	int diff;
18f98b1e PK	225	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
	226
	227	/* make sure the device is disabled */
	228	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN\|OCI2C_CTRL_IEN));
	229
3a33a854 MF	230	prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
	231	prescale = clamp(prescale, 0, 0xffff);
	232
	233	diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;
	234	if (abs(diff) > i2c->bus_clock_khz / 10) {
	235	dev_err(dev,
	236	"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",
	237	i2c->ip_clock_khz, i2c->bus_clock_khz);
	238	return -EINVAL;
	239	}
	240
18f98b1e PK	241	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
	242	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);
	243
	244	/* Init the device */
	245	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
	246	oc_setreg(i2c, OCI2C_CONTROL, ctrl \| OCI2C_CTRL_IEN \| OCI2C_CTRL_EN);
3a33a854 MF	247
3a33a854 MF	248	return 0;
18f98b1e PK	249	}
	250
	251
	252	static u32 ocores_func(struct i2c_adapter *adap)
	253	{
	254	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	255	}
	256
8f9082c5	257	static const struct i2c_algorithm ocores_algorithm = {
1ce97e07 WS	258	.master_xfer = ocores_xfer,
1ce97e07 WS	259	.functionality = ocores_func,
18f98b1e PK	260	};
	261
	262	static struct i2c_adapter ocores_adapter = {
1ce97e07 WS	263	.owner = THIS_MODULE,
	264	.name = "i2c-ocores",
	265	.class = I2C_CLASS_DEPRECATED,
	266	.algo = &ocores_algorithm,
18f98b1e PK	267	};
18f98b1e PK	268
eae45e5d	269	static const struct of_device_id ocores_i2c_match[] = {
a000b8c1 AL	270	{
	271	.compatible = "opencores,i2c-ocores",
	272	.data = (void *)TYPE_OCORES,
	273	},
	274	{
	275	.compatible = "aeroflexgaisler,i2cmst",
	276	.data = (void *)TYPE_GRLIB,
	277	},
	278	{},
	279	};
	280	MODULE_DEVICE_TABLE(of, ocores_i2c_match);
	281
049bb69d	282	#ifdef CONFIG_OF
c5d54744 AL	283	/* Read and write functions for the GRLIB port of the controller. Registers are
	284	* 32-bit big endian and the PRELOW and PREHIGH registers are merged into one
	285	* register. The subsequent registers has their offset decreased accordingly. */
	286	static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg)
	287	{
	288	u32 rd;
	289	int rreg = reg;
	290	if (reg != OCI2C_PRELOW)
	291	rreg--;
	292	rd = ioread32be(i2c->base + (rreg << i2c->reg_shift));
	293	if (reg == OCI2C_PREHIGH)
	294	return (u8)(rd >> 8);
	295	else
	296	return (u8)rd;
	297	}
	298
	299	static void oc_setreg_grlib(struct ocores_i2c *i2c, int reg, u8 value)
	300	{
	301	u32 curr, wr;
	302	int rreg = reg;
	303	if (reg != OCI2C_PRELOW)
	304	rreg--;
	305	if (reg == OCI2C_PRELOW \|\| reg == OCI2C_PREHIGH) {
	306	curr = ioread32be(i2c->base + (rreg << i2c->reg_shift));
	307	if (reg == OCI2C_PRELOW)
	308	wr = (curr & 0xff00) \| value;
	309	else
	310	wr = (((u32)value) << 8) \| (curr & 0xff);
	311	} else {
	312	wr = value;
	313	}
	314	iowrite32be(wr, i2c->base + (rreg << i2c->reg_shift));
	315	}
	316
9ae97a89 J	317	static int ocores_i2c_of_probe(struct platform_device *pdev,
9ae97a89 J	318	struct ocores_i2c *i2c)
049bb69d	319	{
8bb986a8	320	struct device_node *np = pdev->dev.of_node;
a000b8c1	321	const struct of_device_id *match;
8bb986a8	322	u32 val;
3a33a854 MF	323	u32 clock_frequency;
3a33a854 MF	324	bool clock_frequency_present;
8bb986a8 GR	325
	326	if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
	327	/* no 'reg-shift', check for deprecated 'regstep' */
	328	if (!of_property_read_u32(np, "regstep", &val)) {
	329	if (!is_power_of_2(val)) {
	330	dev_err(&pdev->dev, "invalid regstep %d\n",
	331	val);
	332	return -EINVAL;
	333	}
	334	i2c->reg_shift = ilog2(val);
	335	dev_warn(&pdev->dev,
	336	"regstep property deprecated, use reg-shift\n");
	337	}
049bb69d	338	}
049bb69d	339
3a33a854 MF	340	clock_frequency_present = !of_property_read_u32(np, "clock-frequency",
	341	&clock_frequency);
	342	i2c->bus_clock_khz = 100;
	343
e961a094 MF	344	i2c->clk = devm_clk_get(&pdev->dev, NULL);
	345
	346	if (!IS_ERR(i2c->clk)) {
	347	int ret = clk_prepare_enable(i2c->clk);
	348
	349	if (ret) {
	350	dev_err(&pdev->dev,
	351	"clk_prepare_enable failed: %d\n", ret);
	352	return ret;
	353	}
	354	i2c->ip_clock_khz = clk_get_rate(i2c->clk) / 1000;
	355	if (clock_frequency_present)
	356	i2c->bus_clock_khz = clock_frequency / 1000;
0d8fb599 WS	357	}
	358
	359	if (i2c->ip_clock_khz == 0) {
	360	if (of_property_read_u32(np, "opencores,ip-clock-frequency",
	361	&val)) {
	362	if (!clock_frequency_present) {
	363	dev_err(&pdev->dev,
	364	"Missing required parameter 'opencores,ip-clock-frequency'\n");
	365	return -ENODEV;
	366	}
	367	i2c->ip_clock_khz = clock_frequency / 1000;
	368	dev_warn(&pdev->dev,
	369	"Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");
	370	} else {
	371	i2c->ip_clock_khz = val / 1000;
	372	if (clock_frequency_present)
	373	i2c->bus_clock_khz = clock_frequency / 1000;
3a33a854	374	}
049bb69d	375	}
049bb69d	376
7326e38f GR	377	of_property_read_u32(pdev->dev.of_node, "reg-io-width",
7326e38f GR	378	&i2c->reg_io_width);
a000b8c1 AL	379
a000b8c1 AL	380	match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
6beaddf2	381	if (match && (long)match->data == TYPE_GRLIB) {
a000b8c1 AL	382	dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n");
	383	i2c->setreg = oc_setreg_grlib;
	384	i2c->getreg = oc_getreg_grlib;
	385	}
	386
049bb69d JB	387	return 0;
	388	}
	389	#else
	390	#define ocores_i2c_of_probe(pdev,i2c) -ENODEV
	391	#endif
18f98b1e	392
0b255e92	393	static int ocores_i2c_probe(struct platform_device *pdev)
18f98b1e PK	394	{
	395	struct ocores_i2c *i2c;
	396	struct ocores_i2c_platform_data *pdata;
f5f35a92 AL	397	struct resource *res;
f5f35a92 AL	398	int irq;
18f98b1e	399	int ret;
dd14be4c	400	int i;
18f98b1e	401
f5f35a92 AL	402	irq = platform_get_irq(pdev, 0);
	403	if (irq < 0)
	404	return irq;
18f98b1e	405
47def5b8	406	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
18f98b1e PK	407	if (!i2c)
	408	return -ENOMEM;
	409
b7d12a86	410	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
84dbf809 TR	411	i2c->base = devm_ioremap_resource(&pdev->dev, res);
	412	if (IS_ERR(i2c->base))
	413	return PTR_ERR(i2c->base);
18f98b1e	414
6d4028c6	415	pdata = dev_get_platdata(&pdev->dev);
049bb69d	416	if (pdata) {
8bb986a8	417	i2c->reg_shift = pdata->reg_shift;
7326e38f	418	i2c->reg_io_width = pdata->reg_io_width;
3a33a854 MF	419	i2c->ip_clock_khz = pdata->clock_khz;
3a33a854 MF	420	i2c->bus_clock_khz = 100;
049bb69d JB	421	} else {
	422	ret = ocores_i2c_of_probe(pdev, i2c);
	423	if (ret)
	424	return ret;
	425	}
	426
7326e38f GR	427	if (i2c->reg_io_width == 0)
	428	i2c->reg_io_width = 1; /* Set to default value */
	429
a000b8c1 AL	430	if (!i2c->setreg \|\| !i2c->getreg) {
	431	switch (i2c->reg_io_width) {
	432	case 1:
	433	i2c->setreg = oc_setreg_8;
	434	i2c->getreg = oc_getreg_8;
	435	break;
	436
	437	case 2:
	438	i2c->setreg = oc_setreg_16;
	439	i2c->getreg = oc_getreg_16;
	440	break;
	441
	442	case 4:
	443	i2c->setreg = oc_setreg_32;
	444	i2c->getreg = oc_getreg_32;
	445	break;
	446
	447	default:
	448	dev_err(&pdev->dev, "Unsupported I/O width (%d)\n",
	449	i2c->reg_io_width);
	450	return -EINVAL;
	451	}
	452	}
	453
3a33a854 MF	454	ret = ocores_init(&pdev->dev, i2c);
	455	if (ret)
	456	return ret;
18f98b1e PK	457
18f98b1e PK	458	init_waitqueue_head(&i2c->wait);
f5f35a92	459	ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
47def5b8	460	pdev->name, i2c);
18f98b1e PK	461	if (ret) {
18f98b1e PK	462	dev_err(&pdev->dev, "Cannot claim IRQ\n");
47def5b8	463	return ret;
18f98b1e PK	464	}
	465
	466	/* hook up driver to tree */
	467	platform_set_drvdata(pdev, i2c);
	468	i2c->adap = ocores_adapter;
	469	i2c_set_adapdata(&i2c->adap, i2c);
	470	i2c->adap.dev.parent = &pdev->dev;
049bb69d	471	i2c->adap.dev.of_node = pdev->dev.of_node;
18f98b1e PK	472
	473	/* add i2c adapter to i2c tree */
	474	ret = i2c_add_adapter(&i2c->adap);
	475	if (ret) {
	476	dev_err(&pdev->dev, "Failed to add adapter\n");
47def5b8	477	return ret;
18f98b1e PK	478	}
18f98b1e PK	479
dd14be4c	480	/* add in known devices to the bus */
049bb69d JB	481	if (pdata) {
	482	for (i = 0; i < pdata->num_devices; i++)
	483	i2c_new_device(&i2c->adap, pdata->devices + i);
	484	}
dd14be4c	485
18f98b1e	486	return 0;
18f98b1e PK	487	}
18f98b1e PK	488
0b255e92	489	static int ocores_i2c_remove(struct platform_device *pdev)
18f98b1e PK	490	{
18f98b1e PK	491	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
18f98b1e PK	492
	493	/* disable i2c logic */
	494	oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
	495	& ~(OCI2C_CTRL_EN\|OCI2C_CTRL_IEN));
	496
	497	/* remove adapter & data */
	498	i2c_del_adapter(&i2c->adap);
18f98b1e	499
e961a094 MF	500	if (!IS_ERR(i2c->clk))
	501	clk_disable_unprepare(i2c->clk);
	502
18f98b1e PK	503	return 0;
	504	}
	505
f076e916	506	#ifdef CONFIG_PM_SLEEP
84603c7c	507	static int ocores_i2c_suspend(struct device *dev)
2373c180	508	{
84603c7c	509	struct ocores_i2c *i2c = dev_get_drvdata(dev);
2373c180 ML	510	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
	511
	512	/* make sure the device is disabled */
	513	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN\|OCI2C_CTRL_IEN));
	514
e961a094 MF	515	if (!IS_ERR(i2c->clk))
e961a094 MF	516	clk_disable_unprepare(i2c->clk);
2373c180 ML	517	return 0;
	518	}
	519
84603c7c	520	static int ocores_i2c_resume(struct device *dev)
2373c180	521	{
84603c7c	522	struct ocores_i2c *i2c = dev_get_drvdata(dev);
2373c180	523
e961a094	524	if (!IS_ERR(i2c->clk)) {
0d8fb599	525	unsigned long rate;
e961a094 MF	526	int ret = clk_prepare_enable(i2c->clk);
	527
	528	if (ret) {
	529	dev_err(dev,
	530	"clk_prepare_enable failed: %d\n", ret);
	531	return ret;
	532	}
0d8fb599 WS	533	rate = clk_get_rate(i2c->clk) / 1000;
	534	if (rate)
	535	i2c->ip_clock_khz = rate;
e961a094	536	}
3a33a854	537	return ocores_init(dev, i2c);
2373c180	538	}
84603c7c RW	539
	540	static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume);
	541	#define OCORES_I2C_PM (&ocores_i2c_pm)
2373c180	542	#else
84603c7c	543	#define OCORES_I2C_PM NULL
2373c180 ML	544	#endif
2373c180 ML	545
18f98b1e	546	static struct platform_driver ocores_i2c_driver = {
2373c180	547	.probe = ocores_i2c_probe,
0b255e92	548	.remove = ocores_i2c_remove,
2373c180	549	.driver = {
18f98b1e	550	.name = "ocores-i2c",
c9e358df	551	.of_match_table = ocores_i2c_match,
84603c7c	552	.pm = OCORES_I2C_PM,
18f98b1e PK	553	},
	554	};
	555
a3664b51	556	module_platform_driver(ocores_i2c_driver);
18f98b1e PK	557
	558	MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
	559	MODULE_DESCRIPTION("OpenCores I2C bus driver");
	560	MODULE_LICENSE("GPL");
a3664b51	561	MODULE_ALIAS("platform:ocores-i2c");