xref: /openbmc/linux/drivers/i2c/busses/i2c-axxia.c (revision 05cf4fe738242183f1237f1b3a28b4479348c0a1)
1 /*
2  * This driver implements I2C master functionality using the LSI API2C
3  * controller.
4  *
5  * NOTE: The controller has a limitation in that it can only do transfers of
6  * maximum 255 bytes at a time. If a larger transfer is attempted, error code
7  * (-EINVAL) is returned.
8  *
9  * This software is licensed under the terms of the GNU General Public
10  * License version 2, as published by the Free Software Foundation, and
11  * may be copied, distributed, and modified under those terms.
12  */
13 #include <linux/clk.h>
14 #include <linux/clkdev.h>
15 #include <linux/err.h>
16 #include <linux/i2c.h>
17 #include <linux/init.h>
18 #include <linux/interrupt.h>
19 #include <linux/module.h>
20 #include <linux/io.h>
21 #include <linux/kernel.h>
22 #include <linux/platform_device.h>
23 
24 #define SCL_WAIT_TIMEOUT_NS 25000000
25 #define I2C_XFER_TIMEOUT    (msecs_to_jiffies(250))
26 #define I2C_STOP_TIMEOUT    (msecs_to_jiffies(100))
27 #define FIFO_SIZE           8
28 
29 #define GLOBAL_CONTROL		0x00
30 #define   GLOBAL_MST_EN         BIT(0)
31 #define   GLOBAL_SLV_EN         BIT(1)
32 #define   GLOBAL_IBML_EN        BIT(2)
33 #define INTERRUPT_STATUS	0x04
34 #define INTERRUPT_ENABLE	0x08
35 #define   INT_SLV               BIT(1)
36 #define   INT_MST               BIT(0)
37 #define WAIT_TIMER_CONTROL	0x0c
38 #define   WT_EN			BIT(15)
39 #define   WT_VALUE(_x)		((_x) & 0x7fff)
40 #define IBML_TIMEOUT		0x10
41 #define IBML_LOW_MEXT		0x14
42 #define IBML_LOW_SEXT		0x18
43 #define TIMER_CLOCK_DIV		0x1c
44 #define I2C_BUS_MONITOR		0x20
45 #define   BM_SDAC		BIT(3)
46 #define   BM_SCLC		BIT(2)
47 #define   BM_SDAS		BIT(1)
48 #define   BM_SCLS		BIT(0)
49 #define SOFT_RESET		0x24
50 #define MST_COMMAND		0x28
51 #define   CMD_BUSY		(1<<3)
52 #define   CMD_MANUAL		(0x00 | CMD_BUSY)
53 #define   CMD_AUTO		(0x01 | CMD_BUSY)
54 #define MST_RX_XFER		0x2c
55 #define MST_TX_XFER		0x30
56 #define MST_ADDR_1		0x34
57 #define MST_ADDR_2		0x38
58 #define MST_DATA		0x3c
59 #define MST_TX_FIFO		0x40
60 #define MST_RX_FIFO		0x44
61 #define MST_INT_ENABLE		0x48
62 #define MST_INT_STATUS		0x4c
63 #define   MST_STATUS_RFL	(1 << 13) /* RX FIFO serivce */
64 #define   MST_STATUS_TFL	(1 << 12) /* TX FIFO service */
65 #define   MST_STATUS_SNS	(1 << 11) /* Manual mode done */
66 #define   MST_STATUS_SS		(1 << 10) /* Automatic mode done */
67 #define   MST_STATUS_SCC	(1 << 9)  /* Stop complete */
68 #define   MST_STATUS_IP		(1 << 8)  /* Invalid parameter */
69 #define   MST_STATUS_TSS	(1 << 7)  /* Timeout */
70 #define   MST_STATUS_AL		(1 << 6)  /* Arbitration lost */
71 #define   MST_STATUS_ND		(1 << 5)  /* NAK on data phase */
72 #define   MST_STATUS_NA		(1 << 4)  /* NAK on address phase */
73 #define   MST_STATUS_NAK	(MST_STATUS_NA | \
74 				 MST_STATUS_ND)
75 #define   MST_STATUS_ERR	(MST_STATUS_NAK | \
76 				 MST_STATUS_AL  | \
77 				 MST_STATUS_IP)
78 #define MST_TX_BYTES_XFRD	0x50
79 #define MST_RX_BYTES_XFRD	0x54
80 #define SCL_HIGH_PERIOD		0x80
81 #define SCL_LOW_PERIOD		0x84
82 #define SPIKE_FLTR_LEN		0x88
83 #define SDA_SETUP_TIME		0x8c
84 #define SDA_HOLD_TIME		0x90
85 
86 /**
87  * axxia_i2c_dev - I2C device context
88  * @base: pointer to register struct
89  * @msg: pointer to current message
90  * @msg_xfrd: number of bytes transferred in msg
91  * @msg_err: error code for completed message
92  * @msg_complete: xfer completion object
93  * @dev: device reference
94  * @adapter: core i2c abstraction
95  * @i2c_clk: clock reference for i2c input clock
96  * @bus_clk_rate: current i2c bus clock rate
97  */
98 struct axxia_i2c_dev {
99 	void __iomem *base;
100 	struct i2c_msg *msg;
101 	size_t msg_xfrd;
102 	int msg_err;
103 	struct completion msg_complete;
104 	struct device *dev;
105 	struct i2c_adapter adapter;
106 	struct clk *i2c_clk;
107 	u32 bus_clk_rate;
108 };
109 
110 static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
111 {
112 	u32 int_en;
113 
114 	int_en = readl(idev->base + MST_INT_ENABLE);
115 	writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
116 }
117 
118 static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
119 {
120 	u32 int_en;
121 
122 	int_en = readl(idev->base + MST_INT_ENABLE);
123 	writel(int_en | mask, idev->base + MST_INT_ENABLE);
124 }
125 
126 /**
127  * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
128  */
129 static u32 ns_to_clk(u64 ns, u32 clk_mhz)
130 {
131 	return div_u64(ns * clk_mhz, 1000);
132 }
133 
134 static int axxia_i2c_init(struct axxia_i2c_dev *idev)
135 {
136 	u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
137 	u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
138 	u32 t_setup;
139 	u32 t_high, t_low;
140 	u32 tmo_clk;
141 	u32 prescale;
142 	unsigned long timeout;
143 
144 	dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
145 		idev->bus_clk_rate, clk_mhz, divisor);
146 
147 	/* Reset controller */
148 	writel(0x01, idev->base + SOFT_RESET);
149 	timeout = jiffies + msecs_to_jiffies(100);
150 	while (readl(idev->base + SOFT_RESET) & 1) {
151 		if (time_after(jiffies, timeout)) {
152 			dev_warn(idev->dev, "Soft reset failed\n");
153 			break;
154 		}
155 	}
156 
157 	/* Enable Master Mode */
158 	writel(0x1, idev->base + GLOBAL_CONTROL);
159 
160 	if (idev->bus_clk_rate <= 100000) {
161 		/* Standard mode SCL 50/50, tSU:DAT = 250 ns */
162 		t_high = divisor * 1 / 2;
163 		t_low = divisor * 1 / 2;
164 		t_setup = ns_to_clk(250, clk_mhz);
165 	} else {
166 		/* Fast mode SCL 33/66, tSU:DAT = 100 ns */
167 		t_high = divisor * 1 / 3;
168 		t_low = divisor * 2 / 3;
169 		t_setup = ns_to_clk(100, clk_mhz);
170 	}
171 
172 	/* SCL High Time */
173 	writel(t_high, idev->base + SCL_HIGH_PERIOD);
174 	/* SCL Low Time */
175 	writel(t_low, idev->base + SCL_LOW_PERIOD);
176 	/* SDA Setup Time */
177 	writel(t_setup, idev->base + SDA_SETUP_TIME);
178 	/* SDA Hold Time, 300ns */
179 	writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
180 	/* Filter <50ns spikes */
181 	writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
182 
183 	/* Configure Time-Out Registers */
184 	tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
185 
186 	/* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
187 	for (prescale = 0; prescale < 15; ++prescale) {
188 		if (tmo_clk <= 0x7fff)
189 			break;
190 		tmo_clk >>= 1;
191 	}
192 	if (tmo_clk > 0x7fff)
193 		tmo_clk = 0x7fff;
194 
195 	/* Prescale divider (log2) */
196 	writel(prescale, idev->base + TIMER_CLOCK_DIV);
197 	/* Timeout in divided clocks */
198 	writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
199 
200 	/* Mask all master interrupt bits */
201 	i2c_int_disable(idev, ~0);
202 
203 	/* Interrupt enable */
204 	writel(0x01, idev->base + INTERRUPT_ENABLE);
205 
206 	return 0;
207 }
208 
209 static int i2c_m_rd(const struct i2c_msg *msg)
210 {
211 	return (msg->flags & I2C_M_RD) != 0;
212 }
213 
214 static int i2c_m_ten(const struct i2c_msg *msg)
215 {
216 	return (msg->flags & I2C_M_TEN) != 0;
217 }
218 
219 static int i2c_m_recv_len(const struct i2c_msg *msg)
220 {
221 	return (msg->flags & I2C_M_RECV_LEN) != 0;
222 }
223 
224 /**
225  * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
226  * transfer length if this is the first byte of such a transfer.
227  */
228 static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
229 {
230 	struct i2c_msg *msg = idev->msg;
231 	size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
232 	int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd);
233 
234 	while (bytes_to_transfer-- > 0) {
235 		int c = readl(idev->base + MST_DATA);
236 
237 		if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) {
238 			/*
239 			 * Check length byte for SMBus block read
240 			 */
241 			if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
242 				idev->msg_err = -EPROTO;
243 				i2c_int_disable(idev, ~MST_STATUS_TSS);
244 				complete(&idev->msg_complete);
245 				break;
246 			}
247 			msg->len = 1 + c;
248 			writel(msg->len, idev->base + MST_RX_XFER);
249 		}
250 		msg->buf[idev->msg_xfrd++] = c;
251 	}
252 
253 	return 0;
254 }
255 
256 /**
257  * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
258  * @return: Number of bytes left to transfer.
259  */
260 static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
261 {
262 	struct i2c_msg *msg = idev->msg;
263 	size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
264 	int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
265 	int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
266 
267 	while (bytes_to_transfer-- > 0)
268 		writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
269 
270 	return ret;
271 }
272 
273 static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
274 {
275 	struct axxia_i2c_dev *idev = _dev;
276 	u32 status;
277 
278 	if (!(readl(idev->base + INTERRUPT_STATUS) & INT_MST))
279 		return IRQ_NONE;
280 
281 	/* Read interrupt status bits */
282 	status = readl(idev->base + MST_INT_STATUS);
283 
284 	if (!idev->msg) {
285 		dev_warn(idev->dev, "unexpected interrupt\n");
286 		goto out;
287 	}
288 
289 	/* RX FIFO needs service? */
290 	if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
291 		axxia_i2c_empty_rx_fifo(idev);
292 
293 	/* TX FIFO needs service? */
294 	if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
295 		if (axxia_i2c_fill_tx_fifo(idev) == 0)
296 			i2c_int_disable(idev, MST_STATUS_TFL);
297 	}
298 
299 	if (status & MST_STATUS_SCC) {
300 		/* Stop completed */
301 		i2c_int_disable(idev, ~MST_STATUS_TSS);
302 		complete(&idev->msg_complete);
303 	} else if (status & MST_STATUS_SNS) {
304 		/* Transfer done */
305 		i2c_int_disable(idev, ~MST_STATUS_TSS);
306 		if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
307 			axxia_i2c_empty_rx_fifo(idev);
308 		complete(&idev->msg_complete);
309 	} else if (status & MST_STATUS_TSS) {
310 		/* Transfer timeout */
311 		idev->msg_err = -ETIMEDOUT;
312 		i2c_int_disable(idev, ~MST_STATUS_TSS);
313 		complete(&idev->msg_complete);
314 	} else if (unlikely(status & MST_STATUS_ERR)) {
315 		/* Transfer error */
316 		i2c_int_disable(idev, ~0);
317 		if (status & MST_STATUS_AL)
318 			idev->msg_err = -EAGAIN;
319 		else if (status & MST_STATUS_NAK)
320 			idev->msg_err = -ENXIO;
321 		else
322 			idev->msg_err = -EIO;
323 		dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
324 			status,
325 			idev->msg->addr,
326 			readl(idev->base + MST_RX_BYTES_XFRD),
327 			readl(idev->base + MST_RX_XFER),
328 			readl(idev->base + MST_TX_BYTES_XFRD),
329 			readl(idev->base + MST_TX_XFER));
330 		complete(&idev->msg_complete);
331 	}
332 
333 out:
334 	/* Clear interrupt */
335 	writel(INT_MST, idev->base + INTERRUPT_STATUS);
336 
337 	return IRQ_HANDLED;
338 }
339 
340 static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
341 {
342 	u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS;
343 	u32 rx_xfer, tx_xfer;
344 	u32 addr_1, addr_2;
345 	unsigned long time_left;
346 	unsigned int wt_value;
347 
348 	idev->msg = msg;
349 	idev->msg_xfrd = 0;
350 	reinit_completion(&idev->msg_complete);
351 
352 	if (i2c_m_ten(msg)) {
353 		/* 10-bit address
354 		 *   addr_1: 5'b11110 | addr[9:8] | (R/nW)
355 		 *   addr_2: addr[7:0]
356 		 */
357 		addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
358 		if (i2c_m_rd(msg))
359 			addr_1 |= 1;	/* Set the R/nW bit of the address */
360 		addr_2 = msg->addr & 0xFF;
361 	} else {
362 		/* 7-bit address
363 		 *   addr_1: addr[6:0] | (R/nW)
364 		 *   addr_2: dont care
365 		 */
366 		addr_1 = i2c_8bit_addr_from_msg(msg);
367 		addr_2 = 0;
368 	}
369 
370 	if (i2c_m_rd(msg)) {
371 		/* I2C read transfer */
372 		rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
373 		tx_xfer = 0;
374 	} else {
375 		/* I2C write transfer */
376 		rx_xfer = 0;
377 		tx_xfer = msg->len;
378 	}
379 
380 	writel(rx_xfer, idev->base + MST_RX_XFER);
381 	writel(tx_xfer, idev->base + MST_TX_XFER);
382 	writel(addr_1, idev->base + MST_ADDR_1);
383 	writel(addr_2, idev->base + MST_ADDR_2);
384 
385 	if (i2c_m_rd(msg))
386 		int_mask |= MST_STATUS_RFL;
387 	else if (axxia_i2c_fill_tx_fifo(idev) != 0)
388 		int_mask |= MST_STATUS_TFL;
389 
390 	wt_value = WT_VALUE(readl(idev->base + WAIT_TIMER_CONTROL));
391 	/* Disable wait timer temporarly */
392 	writel(wt_value, idev->base + WAIT_TIMER_CONTROL);
393 	/* Check if timeout error happened */
394 	if (idev->msg_err)
395 		goto out;
396 
397 	/* Start manual mode */
398 	writel(CMD_MANUAL, idev->base + MST_COMMAND);
399 
400 	writel(WT_EN | wt_value, idev->base + WAIT_TIMER_CONTROL);
401 
402 	i2c_int_enable(idev, int_mask);
403 
404 	time_left = wait_for_completion_timeout(&idev->msg_complete,
405 					      I2C_XFER_TIMEOUT);
406 
407 	i2c_int_disable(idev, int_mask);
408 
409 	if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
410 		dev_warn(idev->dev, "busy after xfer\n");
411 
412 	if (time_left == 0) {
413 		idev->msg_err = -ETIMEDOUT;
414 		i2c_recover_bus(&idev->adapter);
415 		axxia_i2c_init(idev);
416 	}
417 
418 out:
419 	if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO &&
420 			idev->msg_err != -ETIMEDOUT)
421 		axxia_i2c_init(idev);
422 
423 	return idev->msg_err;
424 }
425 
426 static int axxia_i2c_stop(struct axxia_i2c_dev *idev)
427 {
428 	u32 int_mask = MST_STATUS_ERR | MST_STATUS_SCC | MST_STATUS_TSS;
429 	unsigned long time_left;
430 
431 	reinit_completion(&idev->msg_complete);
432 
433 	/* Issue stop */
434 	writel(0xb, idev->base + MST_COMMAND);
435 	i2c_int_enable(idev, int_mask);
436 	time_left = wait_for_completion_timeout(&idev->msg_complete,
437 					      I2C_STOP_TIMEOUT);
438 	i2c_int_disable(idev, int_mask);
439 	if (time_left == 0)
440 		return -ETIMEDOUT;
441 
442 	if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
443 		dev_warn(idev->dev, "busy after stop\n");
444 
445 	return 0;
446 }
447 
448 static int
449 axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
450 {
451 	struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
452 	int i;
453 	int ret = 0;
454 
455 	idev->msg_err = 0;
456 	i2c_int_enable(idev, MST_STATUS_TSS);
457 
458 	for (i = 0; ret == 0 && i < num; ++i)
459 		ret = axxia_i2c_xfer_msg(idev, &msgs[i]);
460 
461 	axxia_i2c_stop(idev);
462 
463 	return ret ? : i;
464 }
465 
466 static int axxia_i2c_get_scl(struct i2c_adapter *adap)
467 {
468 	struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
469 
470 	return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SCLS);
471 }
472 
473 static void axxia_i2c_set_scl(struct i2c_adapter *adap, int val)
474 {
475 	struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
476 	u32 tmp;
477 
478 	/* Preserve SDA Control */
479 	tmp = readl(idev->base + I2C_BUS_MONITOR) & BM_SDAC;
480 	if (!val)
481 		tmp |= BM_SCLC;
482 	writel(tmp, idev->base + I2C_BUS_MONITOR);
483 }
484 
485 static int axxia_i2c_get_sda(struct i2c_adapter *adap)
486 {
487 	struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
488 
489 	return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SDAS);
490 }
491 
492 static struct i2c_bus_recovery_info axxia_i2c_recovery_info = {
493 	.recover_bus = i2c_generic_scl_recovery,
494 	.get_scl = axxia_i2c_get_scl,
495 	.set_scl = axxia_i2c_set_scl,
496 	.get_sda = axxia_i2c_get_sda,
497 };
498 
499 static u32 axxia_i2c_func(struct i2c_adapter *adap)
500 {
501 	u32 caps = (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
502 		    I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
503 	return caps;
504 }
505 
506 static const struct i2c_algorithm axxia_i2c_algo = {
507 	.master_xfer = axxia_i2c_xfer,
508 	.functionality = axxia_i2c_func,
509 };
510 
511 static const struct i2c_adapter_quirks axxia_i2c_quirks = {
512 	.max_read_len = 255,
513 	.max_write_len = 255,
514 };
515 
516 static int axxia_i2c_probe(struct platform_device *pdev)
517 {
518 	struct device_node *np = pdev->dev.of_node;
519 	struct axxia_i2c_dev *idev = NULL;
520 	struct resource *res;
521 	void __iomem *base;
522 	int irq;
523 	int ret = 0;
524 
525 	idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
526 	if (!idev)
527 		return -ENOMEM;
528 
529 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
530 	base = devm_ioremap_resource(&pdev->dev, res);
531 	if (IS_ERR(base))
532 		return PTR_ERR(base);
533 
534 	irq = platform_get_irq(pdev, 0);
535 	if (irq < 0) {
536 		dev_err(&pdev->dev, "missing interrupt resource\n");
537 		return irq;
538 	}
539 
540 	idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
541 	if (IS_ERR(idev->i2c_clk)) {
542 		dev_err(&pdev->dev, "missing clock\n");
543 		return PTR_ERR(idev->i2c_clk);
544 	}
545 
546 	idev->base = base;
547 	idev->dev = &pdev->dev;
548 	init_completion(&idev->msg_complete);
549 
550 	of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
551 	if (idev->bus_clk_rate == 0)
552 		idev->bus_clk_rate = 100000;	/* default clock rate */
553 
554 	ret = clk_prepare_enable(idev->i2c_clk);
555 	if (ret) {
556 		dev_err(&pdev->dev, "failed to enable clock\n");
557 		return ret;
558 	}
559 
560 	ret = axxia_i2c_init(idev);
561 	if (ret) {
562 		dev_err(&pdev->dev, "failed to initialize\n");
563 		goto error_disable_clk;
564 	}
565 
566 	ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0,
567 			       pdev->name, idev);
568 	if (ret) {
569 		dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq);
570 		goto error_disable_clk;
571 	}
572 
573 	i2c_set_adapdata(&idev->adapter, idev);
574 	strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
575 	idev->adapter.owner = THIS_MODULE;
576 	idev->adapter.algo = &axxia_i2c_algo;
577 	idev->adapter.bus_recovery_info = &axxia_i2c_recovery_info;
578 	idev->adapter.quirks = &axxia_i2c_quirks;
579 	idev->adapter.dev.parent = &pdev->dev;
580 	idev->adapter.dev.of_node = pdev->dev.of_node;
581 
582 	platform_set_drvdata(pdev, idev);
583 
584 	ret = i2c_add_adapter(&idev->adapter);
585 	if (ret)
586 		goto error_disable_clk;
587 
588 	return 0;
589 
590 error_disable_clk:
591 	clk_disable_unprepare(idev->i2c_clk);
592 	return ret;
593 }
594 
595 static int axxia_i2c_remove(struct platform_device *pdev)
596 {
597 	struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
598 
599 	clk_disable_unprepare(idev->i2c_clk);
600 	i2c_del_adapter(&idev->adapter);
601 
602 	return 0;
603 }
604 
605 /* Match table for of_platform binding */
606 static const struct of_device_id axxia_i2c_of_match[] = {
607 	{ .compatible = "lsi,api2c", },
608 	{},
609 };
610 
611 MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
612 
613 static struct platform_driver axxia_i2c_driver = {
614 	.probe = axxia_i2c_probe,
615 	.remove = axxia_i2c_remove,
616 	.driver = {
617 		.name = "axxia-i2c",
618 		.of_match_table = axxia_i2c_of_match,
619 	},
620 };
621 
622 module_platform_driver(axxia_i2c_driver);
623 
624 MODULE_DESCRIPTION("Axxia I2C Bus driver");
625 MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
626 MODULE_LICENSE("GPL v2");
627