[mirror_ubuntu-zesty-kernel.git] / drivers / i2c / busses / i2c-bcm2835.c

/*
 * BCM2835 master mode driver
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define BCM2835_I2C_C		0x0
#define BCM2835_I2C_S		0x4
#define BCM2835_I2C_DLEN	0x8
#define BCM2835_I2C_A		0xc
#define BCM2835_I2C_FIFO	0x10
#define BCM2835_I2C_DIV		0x14
#define BCM2835_I2C_DEL		0x18
#define BCM2835_I2C_CLKT	0x1c

#define BCM2835_I2C_C_READ	BIT(0)
#define BCM2835_I2C_C_CLEAR	BIT(4) /* bits 4 and 5 both clear */
#define BCM2835_I2C_C_ST	BIT(7)
#define BCM2835_I2C_C_INTD	BIT(8)
#define BCM2835_I2C_C_INTT	BIT(9)
#define BCM2835_I2C_C_INTR	BIT(10)
#define BCM2835_I2C_C_I2CEN	BIT(15)

#define BCM2835_I2C_S_TA	BIT(0)
#define BCM2835_I2C_S_DONE	BIT(1)
#define BCM2835_I2C_S_TXW	BIT(2)
#define BCM2835_I2C_S_RXR	BIT(3)
#define BCM2835_I2C_S_TXD	BIT(4)
#define BCM2835_I2C_S_RXD	BIT(5)
#define BCM2835_I2C_S_TXE	BIT(6)
#define BCM2835_I2C_S_RXF	BIT(7)
#define BCM2835_I2C_S_ERR	BIT(8)
#define BCM2835_I2C_S_CLKT	BIT(9)
#define BCM2835_I2C_S_LEN	BIT(10) /* Fake bit for SW error reporting */

#define BCM2835_I2C_BITMSK_S	0x03FF

#define BCM2835_I2C_CDIV_MIN	0x0002
#define BCM2835_I2C_CDIV_MAX	0xFFFE

#define BCM2835_I2C_TIMEOUT (msecs_to_jiffies(1000))

struct bcm2835_i2c_dev {
	struct device *dev;
	void __iomem *regs;
	struct clk *clk;
	int irq;
	struct i2c_adapter adapter;
	struct completion completion;
	u32 msg_err;
	u8 *msg_buf;
	size_t msg_buf_remaining;
};

static inline void bcm2835_i2c_writel(struct bcm2835_i2c_dev *i2c_dev,
				      u32 reg, u32 val)
{
	writel(val, i2c_dev->regs + reg);
}

static inline u32 bcm2835_i2c_readl(struct bcm2835_i2c_dev *i2c_dev, u32 reg)
{
	return readl(i2c_dev->regs + reg);
}

static void bcm2835_fill_txfifo(struct bcm2835_i2c_dev *i2c_dev)
{
	u32 val;

	while (i2c_dev->msg_buf_remaining) {
		val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
		if (!(val & BCM2835_I2C_S_TXD))
			break;
		bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_FIFO,
				   *i2c_dev->msg_buf);
		i2c_dev->msg_buf++;
		i2c_dev->msg_buf_remaining--;
	}
}

static void bcm2835_drain_rxfifo(struct bcm2835_i2c_dev *i2c_dev)
{
	u32 val;

	while (i2c_dev->msg_buf_remaining) {
		val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
		if (!(val & BCM2835_I2C_S_RXD))
			break;
		*i2c_dev->msg_buf = bcm2835_i2c_readl(i2c_dev,
						      BCM2835_I2C_FIFO);
		i2c_dev->msg_buf++;
		i2c_dev->msg_buf_remaining--;
	}
}

static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
{
	struct bcm2835_i2c_dev *i2c_dev = data;
	u32 val, err;

	val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
	val &= BCM2835_I2C_BITMSK_S;
	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_S, val);

	err = val & (BCM2835_I2C_S_CLKT | BCM2835_I2C_S_ERR);
	if (err) {
		i2c_dev->msg_err = err;
		complete(&i2c_dev->completion);
		return IRQ_HANDLED;
	}

	if (val & BCM2835_I2C_S_RXD) {
		bcm2835_drain_rxfifo(i2c_dev);
		if (!(val & BCM2835_I2C_S_DONE))
			return IRQ_HANDLED;
	}

	if (val & BCM2835_I2C_S_DONE) {
		if (i2c_dev->msg_buf_remaining)
			i2c_dev->msg_err = BCM2835_I2C_S_LEN;
		else
			i2c_dev->msg_err = 0;
		complete(&i2c_dev->completion);
		return IRQ_HANDLED;
	}

	if (val & BCM2835_I2C_S_TXD) {
		bcm2835_fill_txfifo(i2c_dev);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
				struct i2c_msg *msg)
{
	u32 c;
	unsigned long time_left;

	i2c_dev->msg_buf = msg->buf;
	i2c_dev->msg_buf_remaining = msg->len;
	reinit_completion(&i2c_dev->completion);

	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);

	if (msg->flags & I2C_M_RD) {
		c = BCM2835_I2C_C_READ | BCM2835_I2C_C_INTR;
	} else {
		c = BCM2835_I2C_C_INTT;
		bcm2835_fill_txfifo(i2c_dev);
	}
	c |= BCM2835_I2C_C_ST | BCM2835_I2C_C_INTD | BCM2835_I2C_C_I2CEN;

	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_A, msg->addr);
	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DLEN, msg->len);
	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, c);

	time_left = wait_for_completion_timeout(&i2c_dev->completion,
						BCM2835_I2C_TIMEOUT);
	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);
	if (!time_left) {
		dev_err(i2c_dev->dev, "i2c transfer timed out\n");
		return -ETIMEDOUT;
	}

	if (likely(!i2c_dev->msg_err))
		return 0;

	if ((i2c_dev->msg_err & BCM2835_I2C_S_ERR) &&
	    (msg->flags & I2C_M_IGNORE_NAK))
		return 0;

	dev_err(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);

	if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
		return -EREMOTEIO;
	else
		return -EIO;
}

static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
			    int num)
{
	struct bcm2835_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
	int i;
	int ret = 0;

	for (i = 0; i < num; i++) {
		ret = bcm2835_i2c_xfer_msg(i2c_dev, &msgs[i]);
		if (ret)
			break;
	}

	return ret ?: i;
}

static u32 bcm2835_i2c_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static const struct i2c_algorithm bcm2835_i2c_algo = {
	.master_xfer	= bcm2835_i2c_xfer,
	.functionality	= bcm2835_i2c_func,
};

/*
 * This HW was reported to have problems with clock stretching:
 * http://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html
 * https://www.raspberrypi.org/forums/viewtopic.php?p=146272
 */
static const struct i2c_adapter_quirks bcm2835_i2c_quirks = {
	.flags = I2C_AQ_NO_CLK_STRETCH,
};

static int bcm2835_i2c_probe(struct platform_device *pdev)
{
	struct bcm2835_i2c_dev *i2c_dev;
	struct resource *mem, *irq;
	u32 bus_clk_rate, divider;
	int ret;
	struct i2c_adapter *adap;

	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
	if (!i2c_dev)
		return -ENOMEM;
	platform_set_drvdata(pdev, i2c_dev);
	i2c_dev->dev = &pdev->dev;
	init_completion(&i2c_dev->completion);

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	i2c_dev->regs = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(i2c_dev->regs))
		return PTR_ERR(i2c_dev->regs);

	i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(i2c_dev->clk)) {
		dev_err(&pdev->dev, "Could not get clock\n");
		return PTR_ERR(i2c_dev->clk);
	}

	ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
				   &bus_clk_rate);
	if (ret < 0) {
		dev_warn(&pdev->dev,
			 "Could not read clock-frequency property\n");
		bus_clk_rate = 100000;
	}

	divider = DIV_ROUND_UP(clk_get_rate(i2c_dev->clk), bus_clk_rate);
	/*
	 * Per the datasheet, the register is always interpreted as an even
	 * number, by rounding down. In other words, the LSB is ignored. So,
	 * if the LSB is set, increment the divider to avoid any issue.
	 */
	if (divider & 1)
		divider++;
	if ((divider < BCM2835_I2C_CDIV_MIN) ||
	    (divider > BCM2835_I2C_CDIV_MAX)) {
		dev_err(&pdev->dev, "Invalid clock-frequency\n");
		return -ENODEV;
	}
	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider);

	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!irq) {
		dev_err(&pdev->dev, "No IRQ resource\n");
		return -ENODEV;
	}
	i2c_dev->irq = irq->start;

	ret = request_irq(i2c_dev->irq, bcm2835_i2c_isr, IRQF_SHARED,
			  dev_name(&pdev->dev), i2c_dev);
	if (ret) {
		dev_err(&pdev->dev, "Could not request IRQ\n");
		return -ENODEV;
	}

	adap = &i2c_dev->adapter;
	i2c_set_adapdata(adap, i2c_dev);
	adap->owner = THIS_MODULE;
	adap->class = I2C_CLASS_DEPRECATED;
	strlcpy(adap->name, "bcm2835 I2C adapter", sizeof(adap->name));
	adap->algo = &bcm2835_i2c_algo;
	adap->dev.parent = &pdev->dev;
	adap->dev.of_node = pdev->dev.of_node;
	adap->quirks = &bcm2835_i2c_quirks;

	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0);

	ret = i2c_add_adapter(adap);
	if (ret)
		free_irq(i2c_dev->irq, i2c_dev);

	return ret;
}

static int bcm2835_i2c_remove(struct platform_device *pdev)
{
	struct bcm2835_i2c_dev *i2c_dev = platform_get_drvdata(pdev);

	free_irq(i2c_dev->irq, i2c_dev);
	i2c_del_adapter(&i2c_dev->adapter);

	return 0;
}

static const struct of_device_id bcm2835_i2c_of_match[] = {
	{ .compatible = "brcm,bcm2835-i2c" },
	{},
};
MODULE_DEVICE_TABLE(of, bcm2835_i2c_of_match);

static struct platform_driver bcm2835_i2c_driver = {
	.probe		= bcm2835_i2c_probe,
	.remove		= bcm2835_i2c_remove,
	.driver		= {
		.name	= "i2c-bcm2835",
		.of_match_table = bcm2835_i2c_of_match,
	},
};
module_platform_driver(bcm2835_i2c_driver);

MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
MODULE_DESCRIPTION("BCM2835 I2C bus adapter");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-bcm2835");
Commit	Line	Data
f3b54b9a SW	1	/*
	2	* BCM2835 master mode driver
	3	*
	4	* This software is licensed under the terms of the GNU General Public
	5	* License version 2, as published by the Free Software Foundation, and
	6	* may be copied, distributed, and modified under those terms.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
	12	*/
	13
	14	#include <linux/clk.h>
	15	#include <linux/completion.h>
	16	#include <linux/err.h>
	17	#include <linux/i2c.h>
	18	#include <linux/interrupt.h>
	19	#include <linux/io.h>
	20	#include <linux/module.h>
	21	#include <linux/platform_device.h>
	22	#include <linux/slab.h>
	23
	24	#define BCM2835_I2C_C 0x0
	25	#define BCM2835_I2C_S 0x4
	26	#define BCM2835_I2C_DLEN 0x8
	27	#define BCM2835_I2C_A 0xc
	28	#define BCM2835_I2C_FIFO 0x10
	29	#define BCM2835_I2C_DIV 0x14
	30	#define BCM2835_I2C_DEL 0x18
	31	#define BCM2835_I2C_CLKT 0x1c
	32
	33	#define BCM2835_I2C_C_READ BIT(0)
	34	#define BCM2835_I2C_C_CLEAR BIT(4) /* bits 4 and 5 both clear */
	35	#define BCM2835_I2C_C_ST BIT(7)
	36	#define BCM2835_I2C_C_INTD BIT(8)
	37	#define BCM2835_I2C_C_INTT BIT(9)
	38	#define BCM2835_I2C_C_INTR BIT(10)
	39	#define BCM2835_I2C_C_I2CEN BIT(15)
	40
	41	#define BCM2835_I2C_S_TA BIT(0)
	42	#define BCM2835_I2C_S_DONE BIT(1)
	43	#define BCM2835_I2C_S_TXW BIT(2)
	44	#define BCM2835_I2C_S_RXR BIT(3)
	45	#define BCM2835_I2C_S_TXD BIT(4)
	46	#define BCM2835_I2C_S_RXD BIT(5)
	47	#define BCM2835_I2C_S_TXE BIT(6)
	48	#define BCM2835_I2C_S_RXF BIT(7)
	49	#define BCM2835_I2C_S_ERR BIT(8)
	50	#define BCM2835_I2C_S_CLKT BIT(9)
	51	#define BCM2835_I2C_S_LEN BIT(10) /* Fake bit for SW error reporting */
	52
7b618638 SW	53	#define BCM2835_I2C_BITMSK_S 0x03FF
7b618638 SW	54
a294aba1 SW	55	#define BCM2835_I2C_CDIV_MIN 0x0002
	56	#define BCM2835_I2C_CDIV_MAX 0xFFFE
	57
f3b54b9a SW	58	#define BCM2835_I2C_TIMEOUT (msecs_to_jiffies(1000))
	59
	60	struct bcm2835_i2c_dev {
	61	struct device *dev;
	62	void __iomem *regs;
	63	struct clk *clk;
	64	int irq;
	65	struct i2c_adapter adapter;
	66	struct completion completion;
	67	u32 msg_err;
	68	u8 *msg_buf;
	69	size_t msg_buf_remaining;
	70	};
	71
	72	static inline void bcm2835_i2c_writel(struct bcm2835_i2c_dev *i2c_dev,
	73	u32 reg, u32 val)
	74	{
	75	writel(val, i2c_dev->regs + reg);
	76	}
	77
	78	static inline u32 bcm2835_i2c_readl(struct bcm2835_i2c_dev *i2c_dev, u32 reg)
	79	{
	80	return readl(i2c_dev->regs + reg);
	81	}
	82
	83	static void bcm2835_fill_txfifo(struct bcm2835_i2c_dev *i2c_dev)
	84	{
	85	u32 val;
	86
	87	while (i2c_dev->msg_buf_remaining) {
	88	val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
	89	if (!(val & BCM2835_I2C_S_TXD))
	90	break;
	91	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_FIFO,
	92	*i2c_dev->msg_buf);
	93	i2c_dev->msg_buf++;
	94	i2c_dev->msg_buf_remaining--;
	95	}
	96	}
	97
	98	static void bcm2835_drain_rxfifo(struct bcm2835_i2c_dev *i2c_dev)
	99	{
	100	u32 val;
	101
	102	while (i2c_dev->msg_buf_remaining) {
	103	val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
	104	if (!(val & BCM2835_I2C_S_RXD))
	105	break;
	106	*i2c_dev->msg_buf = bcm2835_i2c_readl(i2c_dev,
	107	BCM2835_I2C_FIFO);
	108	i2c_dev->msg_buf++;
	109	i2c_dev->msg_buf_remaining--;
	110	}
	111	}
	112
	113	static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data)
	114	{
	115	struct bcm2835_i2c_dev *i2c_dev = data;
	116	u32 val, err;
	117
	118	val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
7b618638	119	val &= BCM2835_I2C_BITMSK_S;
f3b54b9a SW	120	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_S, val);
	121
	122	err = val & (BCM2835_I2C_S_CLKT \| BCM2835_I2C_S_ERR);
	123	if (err) {
	124	i2c_dev->msg_err = err;
	125	complete(&i2c_dev->completion);
	126	return IRQ_HANDLED;
	127	}
	128
	129	if (val & BCM2835_I2C_S_RXD) {
	130	bcm2835_drain_rxfifo(i2c_dev);
	131	if (!(val & BCM2835_I2C_S_DONE))
	132	return IRQ_HANDLED;
	133	}
	134
	135	if (val & BCM2835_I2C_S_DONE) {
	136	if (i2c_dev->msg_buf_remaining)
	137	i2c_dev->msg_err = BCM2835_I2C_S_LEN;
	138	else
	139	i2c_dev->msg_err = 0;
	140	complete(&i2c_dev->completion);
	141	return IRQ_HANDLED;
	142	}
	143
	144	if (val & BCM2835_I2C_S_TXD) {
	145	bcm2835_fill_txfifo(i2c_dev);
	146	return IRQ_HANDLED;
	147	}
	148
	149	return IRQ_NONE;
	150	}
	151
	152	static int bcm2835_i2c_xfer_msg(struct bcm2835_i2c_dev *i2c_dev,
	153	struct i2c_msg *msg)
	154	{
	155	u32 c;
c4dc1216	156	unsigned long time_left;
f3b54b9a SW	157
	158	i2c_dev->msg_buf = msg->buf;
	159	i2c_dev->msg_buf_remaining = msg->len;
16735d02	160	reinit_completion(&i2c_dev->completion);
f3b54b9a SW	161
	162	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);
	163
	164	if (msg->flags & I2C_M_RD) {
	165	c = BCM2835_I2C_C_READ \| BCM2835_I2C_C_INTR;
	166	} else {
	167	c = BCM2835_I2C_C_INTT;
	168	bcm2835_fill_txfifo(i2c_dev);
	169	}
	170	c \|= BCM2835_I2C_C_ST \| BCM2835_I2C_C_INTD \| BCM2835_I2C_C_I2CEN;
	171
	172	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_A, msg->addr);
	173	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DLEN, msg->len);
	174	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, c);
	175
	176	time_left = wait_for_completion_timeout(&i2c_dev->completion,
	177	BCM2835_I2C_TIMEOUT);
	178	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, BCM2835_I2C_C_CLEAR);
	179	if (!time_left) {
	180	dev_err(i2c_dev->dev, "i2c transfer timed out\n");
	181	return -ETIMEDOUT;
	182	}
	183
	184	if (likely(!i2c_dev->msg_err))
	185	return 0;
	186
	187	if ((i2c_dev->msg_err & BCM2835_I2C_S_ERR) &&
	188	(msg->flags & I2C_M_IGNORE_NAK))
	189	return 0;
	190
	191	dev_err(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
	192
	193	if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
	194	return -EREMOTEIO;
	195	else
	196	return -EIO;
	197	}
	198
	199	static int bcm2835_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
	200	int num)
	201	{
	202	struct bcm2835_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
	203	int i;
	204	int ret = 0;
	205
	206	for (i = 0; i < num; i++) {
	207	ret = bcm2835_i2c_xfer_msg(i2c_dev, &msgs[i]);
	208	if (ret)
	209	break;
	210	}
	211
	212	return ret ?: i;
	213	}
	214
	215	static u32 bcm2835_i2c_func(struct i2c_adapter *adap)
	216	{
	217	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	218	}
	219
	220	static const struct i2c_algorithm bcm2835_i2c_algo = {
	221	.master_xfer = bcm2835_i2c_xfer,
	222	.functionality = bcm2835_i2c_func,
	223	};
	224
4dbfb5f4 NC	225	/*
	226	* This HW was reported to have problems with clock stretching:
	227	* http://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html
	228	* https://www.raspberrypi.org/forums/viewtopic.php?p=146272
	229	*/
	230	static const struct i2c_adapter_quirks bcm2835_i2c_quirks = {
	231	.flags = I2C_AQ_NO_CLK_STRETCH,
	232	};
	233
f3b54b9a SW	234	static int bcm2835_i2c_probe(struct platform_device *pdev)
	235	{
	236	struct bcm2835_i2c_dev *i2c_dev;
ae50b1df	237	struct resource mem, irq;
f3b54b9a SW	238	u32 bus_clk_rate, divider;
	239	int ret;
	240	struct i2c_adapter *adap;
	241
	242	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
46797a2a	243	if (!i2c_dev)
f3b54b9a	244	return -ENOMEM;
f3b54b9a SW	245	platform_set_drvdata(pdev, i2c_dev);
	246	i2c_dev->dev = &pdev->dev;
	247	init_completion(&i2c_dev->completion);
	248
	249	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ae50b1df JH	250	i2c_dev->regs = devm_ioremap_resource(&pdev->dev, mem);
	251	if (IS_ERR(i2c_dev->regs))
	252	return PTR_ERR(i2c_dev->regs);
f3b54b9a SW	253
	254	i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
	255	if (IS_ERR(i2c_dev->clk)) {
	256	dev_err(&pdev->dev, "Could not get clock\n");
	257	return PTR_ERR(i2c_dev->clk);
	258	}
	259
	260	ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
	261	&bus_clk_rate);
	262	if (ret < 0) {
	263	dev_warn(&pdev->dev,
	264	"Could not read clock-frequency property\n");
	265	bus_clk_rate = 100000;
	266	}
	267
	268	divider = DIV_ROUND_UP(clk_get_rate(i2c_dev->clk), bus_clk_rate);
	269	/*
	270	* Per the datasheet, the register is always interpreted as an even
	271	* number, by rounding down. In other words, the LSB is ignored. So,
	272	* if the LSB is set, increment the divider to avoid any issue.
	273	*/
	274	if (divider & 1)
	275	divider++;
a294aba1 SW	276	if ((divider < BCM2835_I2C_CDIV_MIN) \|\|
	277	(divider > BCM2835_I2C_CDIV_MAX)) {
	278	dev_err(&pdev->dev, "Invalid clock-frequency\n");
	279	return -ENODEV;
	280	}
f3b54b9a SW	281	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider);
	282
	283	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	284	if (!irq) {
	285	dev_err(&pdev->dev, "No IRQ resource\n");
	286	return -ENODEV;
	287	}
	288	i2c_dev->irq = irq->start;
	289
	290	ret = request_irq(i2c_dev->irq, bcm2835_i2c_isr, IRQF_SHARED,
	291	dev_name(&pdev->dev), i2c_dev);
	292	if (ret) {
	293	dev_err(&pdev->dev, "Could not request IRQ\n");
	294	return -ENODEV;
	295	}
	296
	297	adap = &i2c_dev->adapter;
	298	i2c_set_adapdata(adap, i2c_dev);
	299	adap->owner = THIS_MODULE;
37e4f91a	300	adap->class = I2C_CLASS_DEPRECATED;
f3b54b9a SW	301	strlcpy(adap->name, "bcm2835 I2C adapter", sizeof(adap->name));
	302	adap->algo = &bcm2835_i2c_algo;
	303	adap->dev.parent = &pdev->dev;
07a27a00	304	adap->dev.of_node = pdev->dev.of_node;
4dbfb5f4	305	adap->quirks = &bcm2835_i2c_quirks;
f3b54b9a SW	306
	307	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0);
	308
	309	ret = i2c_add_adapter(adap);
	310	if (ret)
	311	free_irq(i2c_dev->irq, i2c_dev);
	312
	313	return ret;
	314	}
	315
	316	static int bcm2835_i2c_remove(struct platform_device *pdev)
	317	{
	318	struct bcm2835_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
	319
	320	free_irq(i2c_dev->irq, i2c_dev);
	321	i2c_del_adapter(&i2c_dev->adapter);
	322
	323	return 0;
	324	}
	325
	326	static const struct of_device_id bcm2835_i2c_of_match[] = {
	327	{ .compatible = "brcm,bcm2835-i2c" },
	328	{},
	329	};
	330	MODULE_DEVICE_TABLE(of, bcm2835_i2c_of_match);
	331
	332	static struct platform_driver bcm2835_i2c_driver = {
	333	.probe = bcm2835_i2c_probe,
	334	.remove = bcm2835_i2c_remove,
	335	.driver = {
	336	.name = "i2c-bcm2835",
f3b54b9a SW	337	.of_match_table = bcm2835_i2c_of_match,
	338	},
	339	};
	340	module_platform_driver(bcm2835_i2c_driver);
	341
	342	MODULE_AUTHOR("Stephen Warren <swarren@wwwdotorg.org>");
	343	MODULE_DESCRIPTION("BCM2835 I2C bus adapter");
	344	MODULE_LICENSE("GPL v2");
	345	MODULE_ALIAS("platform:i2c-bcm2835");