1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * I2C bus driver for the Cadence I2C controller.
4 *
5 * Copyright (C) 2009 - 2014 Xilinx, Inc.
6 */
7
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/i2c.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/iopoll.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/of.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/pinctrl/consumer.h>
19 #include <linux/reset.h>
20
21 /* Register offsets for the I2C device. */
22 #define CDNS_I2C_CR_OFFSET 0x00 /* Control Register, RW */
23 #define CDNS_I2C_SR_OFFSET 0x04 /* Status Register, RO */
24 #define CDNS_I2C_ADDR_OFFSET 0x08 /* I2C Address Register, RW */
25 #define CDNS_I2C_DATA_OFFSET 0x0C /* I2C Data Register, RW */
26 #define CDNS_I2C_ISR_OFFSET 0x10 /* IRQ Status Register, RW */
27 #define CDNS_I2C_XFER_SIZE_OFFSET 0x14 /* Transfer Size Register, RW */
28 #define CDNS_I2C_TIME_OUT_OFFSET 0x1C /* Time Out Register, RW */
29 #define CDNS_I2C_IMR_OFFSET 0x20 /* IRQ Mask Register, RO */
30 #define CDNS_I2C_IER_OFFSET 0x24 /* IRQ Enable Register, WO */
31 #define CDNS_I2C_IDR_OFFSET 0x28 /* IRQ Disable Register, WO */
32
33 /* Control Register Bit mask definitions */
34 #define CDNS_I2C_CR_HOLD BIT(4) /* Hold Bus bit */
35 #define CDNS_I2C_CR_ACK_EN BIT(3)
36 #define CDNS_I2C_CR_NEA BIT(2)
37 #define CDNS_I2C_CR_MS BIT(1)
38 /* Read or Write Master transfer 0 = Transmitter, 1 = Receiver */
39 #define CDNS_I2C_CR_RW BIT(0)
40 /* 1 = Auto init FIFO to zeroes */
41 #define CDNS_I2C_CR_CLR_FIFO BIT(6)
42 #define CDNS_I2C_CR_DIVA_SHIFT 14
43 #define CDNS_I2C_CR_DIVA_MASK (3 << CDNS_I2C_CR_DIVA_SHIFT)
44 #define CDNS_I2C_CR_DIVB_SHIFT 8
45 #define CDNS_I2C_CR_DIVB_MASK (0x3f << CDNS_I2C_CR_DIVB_SHIFT)
46
47 #define CDNS_I2C_CR_MASTER_EN_MASK (CDNS_I2C_CR_NEA | \
48 CDNS_I2C_CR_ACK_EN | \
49 CDNS_I2C_CR_MS)
50
51 #define CDNS_I2C_CR_SLAVE_EN_MASK ~CDNS_I2C_CR_MASTER_EN_MASK
52
53 /* Status Register Bit mask definitions */
54 #define CDNS_I2C_SR_BA BIT(8)
55 #define CDNS_I2C_SR_TXDV BIT(6)
56 #define CDNS_I2C_SR_RXDV BIT(5)
57 #define CDNS_I2C_SR_RXRW BIT(3)
58
59 /*
60 * I2C Address Register Bit mask definitions
61 * Normal addressing mode uses [6:0] bits. Extended addressing mode uses [9:0]
62 * bits. A write access to this register always initiates a transfer if the I2C
63 * is in master mode.
64 */
65 #define CDNS_I2C_ADDR_MASK 0x000003FF /* I2C Address Mask */
66
67 /*
68 * I2C Interrupt Registers Bit mask definitions
69 * All the four interrupt registers (Status/Mask/Enable/Disable) have the same
70 * bit definitions.
71 */
72 #define CDNS_I2C_IXR_ARB_LOST BIT(9)
73 #define CDNS_I2C_IXR_RX_UNF BIT(7)
74 #define CDNS_I2C_IXR_TX_OVF BIT(6)
75 #define CDNS_I2C_IXR_RX_OVF BIT(5)
76 #define CDNS_I2C_IXR_SLV_RDY BIT(4)
77 #define CDNS_I2C_IXR_TO BIT(3)
78 #define CDNS_I2C_IXR_NACK BIT(2)
79 #define CDNS_I2C_IXR_DATA BIT(1)
80 #define CDNS_I2C_IXR_COMP BIT(0)
81
82 #define CDNS_I2C_IXR_ALL_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
83 CDNS_I2C_IXR_RX_UNF | \
84 CDNS_I2C_IXR_TX_OVF | \
85 CDNS_I2C_IXR_RX_OVF | \
86 CDNS_I2C_IXR_SLV_RDY | \
87 CDNS_I2C_IXR_TO | \
88 CDNS_I2C_IXR_NACK | \
89 CDNS_I2C_IXR_DATA | \
90 CDNS_I2C_IXR_COMP)
91
92 #define CDNS_I2C_IXR_ERR_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
93 CDNS_I2C_IXR_RX_UNF | \
94 CDNS_I2C_IXR_TX_OVF | \
95 CDNS_I2C_IXR_RX_OVF | \
96 CDNS_I2C_IXR_NACK)
97
98 #define CDNS_I2C_ENABLED_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
99 CDNS_I2C_IXR_RX_UNF | \
100 CDNS_I2C_IXR_TX_OVF | \
101 CDNS_I2C_IXR_RX_OVF | \
102 CDNS_I2C_IXR_NACK | \
103 CDNS_I2C_IXR_DATA | \
104 CDNS_I2C_IXR_COMP)
105
106 #define CDNS_I2C_IXR_SLAVE_INTR_MASK (CDNS_I2C_IXR_RX_UNF | \
107 CDNS_I2C_IXR_TX_OVF | \
108 CDNS_I2C_IXR_RX_OVF | \
109 CDNS_I2C_IXR_TO | \
110 CDNS_I2C_IXR_NACK | \
111 CDNS_I2C_IXR_DATA | \
112 CDNS_I2C_IXR_COMP)
113
114 #define CDNS_I2C_TIMEOUT msecs_to_jiffies(1000)
115 /* timeout for pm runtime autosuspend */
116 #define CNDS_I2C_PM_TIMEOUT 1000 /* ms */
117
118 #define CDNS_I2C_FIFO_DEPTH_DEFAULT 16
119 #define CDNS_I2C_MAX_TRANSFER_SIZE 255
120 /* Transfer size in multiples of data interrupt depth */
121 #define CDNS_I2C_TRANSFER_SIZE(max) ((max) - 3)
122
123 #define DRIVER_NAME "cdns-i2c"
124
125 #define CDNS_I2C_DIVA_MAX 4
126 #define CDNS_I2C_DIVB_MAX 64
127
128 #define CDNS_I2C_TIMEOUT_MAX 0xFF
129
130 #define CDNS_I2C_BROKEN_HOLD_BIT BIT(0)
131 #define CDNS_I2C_POLL_US 100000
132 #define CDNS_I2C_TIMEOUT_US 500000
133
134 #define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset)
135 #define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset)
136
137 #if IS_ENABLED(CONFIG_I2C_SLAVE)
138 /**
139 * enum cdns_i2c_mode - I2C Controller current operating mode
140 *
141 * @CDNS_I2C_MODE_SLAVE: I2C controller operating in slave mode
142 * @CDNS_I2C_MODE_MASTER: I2C Controller operating in master mode
143 */
144 enum cdns_i2c_mode {
145 CDNS_I2C_MODE_SLAVE,
146 CDNS_I2C_MODE_MASTER,
147 };
148
149 /**
150 * enum cdns_i2c_slave_state - Slave state when I2C is operating in slave mode
151 *
152 * @CDNS_I2C_SLAVE_STATE_IDLE: I2C slave idle
153 * @CDNS_I2C_SLAVE_STATE_SEND: I2C slave sending data to master
154 * @CDNS_I2C_SLAVE_STATE_RECV: I2C slave receiving data from master
155 */
156 enum cdns_i2c_slave_state {
157 CDNS_I2C_SLAVE_STATE_IDLE,
158 CDNS_I2C_SLAVE_STATE_SEND,
159 CDNS_I2C_SLAVE_STATE_RECV,
160 };
161 #endif
162
163 /**
164 * struct cdns_i2c - I2C device private data structure
165 *
166 * @dev: Pointer to device structure
167 * @membase: Base address of the I2C device
168 * @adap: I2C adapter instance
169 * @p_msg: Message pointer
170 * @err_status: Error status in Interrupt Status Register
171 * @xfer_done: Transfer complete status
172 * @p_send_buf: Pointer to transmit buffer
173 * @p_recv_buf: Pointer to receive buffer
174 * @send_count: Number of bytes still expected to send
175 * @recv_count: Number of bytes still expected to receive
176 * @curr_recv_count: Number of bytes to be received in current transfer
177 * @input_clk: Input clock to I2C controller
178 * @i2c_clk: Maximum I2C clock speed
179 * @bus_hold_flag: Flag used in repeated start for clearing HOLD bit
180 * @clk: Pointer to struct clk
181 * @clk_rate_change_nb: Notifier block for clock rate changes
182 * @reset: Reset control for the device
183 * @quirks: flag for broken hold bit usage in r1p10
184 * @ctrl_reg: Cached value of the control register.
185 * @rinfo: I2C GPIO recovery information
186 * @ctrl_reg_diva_divb: value of fields DIV_A and DIV_B from CR register
187 * @slave: Registered slave instance.
188 * @dev_mode: I2C operating role(master/slave).
189 * @slave_state: I2C Slave state(idle/read/write).
190 * @fifo_depth: The depth of the transfer FIFO
191 * @transfer_size: The maximum number of bytes in one transfer
192 */
193 struct cdns_i2c {
194 struct device *dev;
195 void __iomem *membase;
196 struct i2c_adapter adap;
197 struct i2c_msg *p_msg;
198 int err_status;
199 struct completion xfer_done;
200 unsigned char *p_send_buf;
201 unsigned char *p_recv_buf;
202 unsigned int send_count;
203 unsigned int recv_count;
204 unsigned int curr_recv_count;
205 unsigned long input_clk;
206 unsigned int i2c_clk;
207 unsigned int bus_hold_flag;
208 struct clk *clk;
209 struct notifier_block clk_rate_change_nb;
210 struct reset_control *reset;
211 u32 quirks;
212 u32 ctrl_reg;
213 struct i2c_bus_recovery_info rinfo;
214 #if IS_ENABLED(CONFIG_I2C_SLAVE)
215 u16 ctrl_reg_diva_divb;
216 struct i2c_client *slave;
217 enum cdns_i2c_mode dev_mode;
218 enum cdns_i2c_slave_state slave_state;
219 #endif
220 u32 fifo_depth;
221 unsigned int transfer_size;
222 };
223
224 struct cdns_platform_data {
225 u32 quirks;
226 };
227
228 #define to_cdns_i2c(_nb) container_of(_nb, struct cdns_i2c, \
229 clk_rate_change_nb)
230
231 /**
232 * cdns_i2c_clear_bus_hold - Clear bus hold bit
233 * @id: Pointer to driver data struct
234 *
235 * Helper to clear the controller's bus hold bit.
236 */
cdns_i2c_clear_bus_hold(struct cdns_i2c * id)237 static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id)
238 {
239 u32 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
240 if (reg & CDNS_I2C_CR_HOLD)
241 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_HOLD, CDNS_I2C_CR_OFFSET);
242 }
243
cdns_is_holdquirk(struct cdns_i2c * id,bool hold_wrkaround)244 static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround)
245 {
246 return (hold_wrkaround &&
247 (id->curr_recv_count == id->fifo_depth + 1));
248 }
249
250 #if IS_ENABLED(CONFIG_I2C_SLAVE)
cdns_i2c_set_mode(enum cdns_i2c_mode mode,struct cdns_i2c * id)251 static void cdns_i2c_set_mode(enum cdns_i2c_mode mode, struct cdns_i2c *id)
252 {
253 /* Disable all interrupts */
254 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET);
255
256 /* Clear FIFO and transfer size */
257 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET);
258
259 /* Update device mode and state */
260 id->dev_mode = mode;
261 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
262
263 switch (mode) {
264 case CDNS_I2C_MODE_MASTER:
265 /* Enable i2c master */
266 cdns_i2c_writereg(id->ctrl_reg_diva_divb |
267 CDNS_I2C_CR_MASTER_EN_MASK,
268 CDNS_I2C_CR_OFFSET);
269 /*
270 * This delay is needed to give the IP some time to switch to
271 * the master mode. With lower values(like 110 us) i2cdetect
272 * will not detect any slave and without this delay, the IP will
273 * trigger a timeout interrupt.
274 */
275 usleep_range(115, 125);
276 break;
277 case CDNS_I2C_MODE_SLAVE:
278 /* Enable i2c slave */
279 cdns_i2c_writereg(id->ctrl_reg_diva_divb &
280 CDNS_I2C_CR_SLAVE_EN_MASK,
281 CDNS_I2C_CR_OFFSET);
282
283 /* Setting slave address */
284 cdns_i2c_writereg(id->slave->addr & CDNS_I2C_ADDR_MASK,
285 CDNS_I2C_ADDR_OFFSET);
286
287 /* Enable slave send/receive interrupts */
288 cdns_i2c_writereg(CDNS_I2C_IXR_SLAVE_INTR_MASK,
289 CDNS_I2C_IER_OFFSET);
290 break;
291 }
292 }
293
cdns_i2c_slave_rcv_data(struct cdns_i2c * id)294 static void cdns_i2c_slave_rcv_data(struct cdns_i2c *id)
295 {
296 u8 bytes;
297 unsigned char data;
298
299 /* Prepare backend for data reception */
300 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) {
301 id->slave_state = CDNS_I2C_SLAVE_STATE_RECV;
302 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_REQUESTED, NULL);
303 }
304
305 /* Fetch number of bytes to receive */
306 bytes = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
307
308 /* Read data and send to backend */
309 while (bytes--) {
310 data = cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
311 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_RECEIVED, &data);
312 }
313 }
314
cdns_i2c_slave_send_data(struct cdns_i2c * id)315 static void cdns_i2c_slave_send_data(struct cdns_i2c *id)
316 {
317 u8 data;
318
319 /* Prepare backend for data transmission */
320 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) {
321 id->slave_state = CDNS_I2C_SLAVE_STATE_SEND;
322 i2c_slave_event(id->slave, I2C_SLAVE_READ_REQUESTED, &data);
323 } else {
324 i2c_slave_event(id->slave, I2C_SLAVE_READ_PROCESSED, &data);
325 }
326
327 /* Send data over bus */
328 cdns_i2c_writereg(data, CDNS_I2C_DATA_OFFSET);
329 }
330
331 /**
332 * cdns_i2c_slave_isr - Interrupt handler for the I2C device in slave role
333 * @ptr: Pointer to I2C device private data
334 *
335 * This function handles the data interrupt and transfer complete interrupt of
336 * the I2C device in slave role.
337 *
338 * Return: IRQ_HANDLED always
339 */
cdns_i2c_slave_isr(void * ptr)340 static irqreturn_t cdns_i2c_slave_isr(void *ptr)
341 {
342 struct cdns_i2c *id = ptr;
343 unsigned int isr_status, i2c_status;
344
345 /* Fetch the interrupt status */
346 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
347 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
348
349 /* Ignore masked interrupts */
350 isr_status &= ~cdns_i2c_readreg(CDNS_I2C_IMR_OFFSET);
351
352 /* Fetch transfer mode (send/receive) */
353 i2c_status = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET);
354
355 /* Handle data send/receive */
356 if (i2c_status & CDNS_I2C_SR_RXRW) {
357 /* Send data to master */
358 if (isr_status & CDNS_I2C_IXR_DATA)
359 cdns_i2c_slave_send_data(id);
360
361 if (isr_status & CDNS_I2C_IXR_COMP) {
362 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
363 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL);
364 }
365 } else {
366 /* Receive data from master */
367 if (isr_status & CDNS_I2C_IXR_DATA)
368 cdns_i2c_slave_rcv_data(id);
369
370 if (isr_status & CDNS_I2C_IXR_COMP) {
371 cdns_i2c_slave_rcv_data(id);
372 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
373 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL);
374 }
375 }
376
377 /* Master indicated xfer stop or fifo underflow/overflow */
378 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_RX_OVF |
379 CDNS_I2C_IXR_RX_UNF | CDNS_I2C_IXR_TX_OVF)) {
380 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
381 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL);
382 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET);
383 }
384
385 return IRQ_HANDLED;
386 }
387 #endif
388
389 /**
390 * cdns_i2c_master_isr - Interrupt handler for the I2C device in master role
391 * @ptr: Pointer to I2C device private data
392 *
393 * This function handles the data interrupt, transfer complete interrupt and
394 * the error interrupts of the I2C device in master role.
395 *
396 * Return: IRQ_HANDLED always
397 */
cdns_i2c_master_isr(void * ptr)398 static irqreturn_t cdns_i2c_master_isr(void *ptr)
399 {
400 unsigned int isr_status, avail_bytes;
401 unsigned int bytes_to_send;
402 bool updatetx;
403 struct cdns_i2c *id = ptr;
404 /* Signal completion only after everything is updated */
405 int done_flag = 0;
406 irqreturn_t status = IRQ_NONE;
407
408 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
409 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
410 id->err_status = 0;
411
412 /* Handling nack and arbitration lost interrupt */
413 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) {
414 done_flag = 1;
415 status = IRQ_HANDLED;
416 }
417
418 /*
419 * Check if transfer size register needs to be updated again for a
420 * large data receive operation.
421 */
422 updatetx = id->recv_count > id->curr_recv_count;
423
424 /* When receiving, handle data interrupt and completion interrupt */
425 if (id->p_recv_buf &&
426 ((isr_status & CDNS_I2C_IXR_COMP) ||
427 (isr_status & CDNS_I2C_IXR_DATA))) {
428 /* Read data if receive data valid is set */
429 while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) &
430 CDNS_I2C_SR_RXDV) {
431 if (id->recv_count > 0) {
432 *(id->p_recv_buf)++ =
433 cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
434 id->recv_count--;
435 id->curr_recv_count--;
436
437 /*
438 * Clear hold bit that was set for FIFO control
439 * if RX data left is less than or equal to
440 * FIFO DEPTH unless repeated start is selected
441 */
442 if (id->recv_count <= id->fifo_depth &&
443 !id->bus_hold_flag)
444 cdns_i2c_clear_bus_hold(id);
445
446 } else {
447 dev_err(id->adap.dev.parent,
448 "xfer_size reg rollover. xfer aborted!\n");
449 id->err_status |= CDNS_I2C_IXR_TO;
450 break;
451 }
452
453 if (cdns_is_holdquirk(id, updatetx))
454 break;
455 }
456
457 /*
458 * The controller sends NACK to the slave when transfer size
459 * register reaches zero without considering the HOLD bit.
460 * This workaround is implemented for large data transfers to
461 * maintain transfer size non-zero while performing a large
462 * receive operation.
463 */
464 if (cdns_is_holdquirk(id, updatetx)) {
465 /* wait while fifo is full */
466 while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) !=
467 (id->curr_recv_count - id->fifo_depth))
468 ;
469
470 /*
471 * Check number of bytes to be received against maximum
472 * transfer size and update register accordingly.
473 */
474 if (((int)(id->recv_count) - id->fifo_depth) >
475 id->transfer_size) {
476 cdns_i2c_writereg(id->transfer_size,
477 CDNS_I2C_XFER_SIZE_OFFSET);
478 id->curr_recv_count = id->transfer_size +
479 id->fifo_depth;
480 } else {
481 cdns_i2c_writereg(id->recv_count -
482 id->fifo_depth,
483 CDNS_I2C_XFER_SIZE_OFFSET);
484 id->curr_recv_count = id->recv_count;
485 }
486 }
487
488 /* Clear hold (if not repeated start) and signal completion */
489 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->recv_count) {
490 if (!id->bus_hold_flag)
491 cdns_i2c_clear_bus_hold(id);
492 done_flag = 1;
493 }
494
495 status = IRQ_HANDLED;
496 }
497
498 /* When sending, handle transfer complete interrupt */
499 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->p_recv_buf) {
500 /*
501 * If there is more data to be sent, calculate the
502 * space available in FIFO and fill with that many bytes.
503 */
504 if (id->send_count) {
505 avail_bytes = id->fifo_depth -
506 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
507 if (id->send_count > avail_bytes)
508 bytes_to_send = avail_bytes;
509 else
510 bytes_to_send = id->send_count;
511
512 while (bytes_to_send--) {
513 cdns_i2c_writereg(
514 (*(id->p_send_buf)++),
515 CDNS_I2C_DATA_OFFSET);
516 id->send_count--;
517 }
518 } else {
519 /*
520 * Signal the completion of transaction and
521 * clear the hold bus bit if there are no
522 * further messages to be processed.
523 */
524 done_flag = 1;
525 }
526 if (!id->send_count && !id->bus_hold_flag)
527 cdns_i2c_clear_bus_hold(id);
528
529 status = IRQ_HANDLED;
530 }
531
532 /* Update the status for errors */
533 id->err_status |= isr_status & CDNS_I2C_IXR_ERR_INTR_MASK;
534 if (id->err_status)
535 status = IRQ_HANDLED;
536
537 if (done_flag)
538 complete(&id->xfer_done);
539
540 return status;
541 }
542
543 /**
544 * cdns_i2c_isr - Interrupt handler for the I2C device
545 * @irq: irq number for the I2C device
546 * @ptr: void pointer to cdns_i2c structure
547 *
548 * This function passes the control to slave/master based on current role of
549 * i2c controller.
550 *
551 * Return: IRQ_HANDLED always
552 */
cdns_i2c_isr(int irq,void * ptr)553 static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
554 {
555 #if IS_ENABLED(CONFIG_I2C_SLAVE)
556 struct cdns_i2c *id = ptr;
557
558 if (id->dev_mode == CDNS_I2C_MODE_SLAVE)
559 return cdns_i2c_slave_isr(ptr);
560 #endif
561 return cdns_i2c_master_isr(ptr);
562 }
563
564 /**
565 * cdns_i2c_mrecv - Prepare and start a master receive operation
566 * @id: pointer to the i2c device structure
567 */
cdns_i2c_mrecv(struct cdns_i2c * id)568 static void cdns_i2c_mrecv(struct cdns_i2c *id)
569 {
570 unsigned int ctrl_reg;
571 unsigned int isr_status;
572 unsigned long flags;
573 bool hold_clear = false;
574 bool irq_save = false;
575
576 u32 addr;
577
578 id->p_recv_buf = id->p_msg->buf;
579 id->recv_count = id->p_msg->len;
580
581 /* Put the controller in master receive mode and clear the FIFO */
582 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
583 ctrl_reg |= CDNS_I2C_CR_RW | CDNS_I2C_CR_CLR_FIFO;
584
585 /*
586 * Receive up to I2C_SMBUS_BLOCK_MAX data bytes, plus one message length
587 * byte, plus one checksum byte if PEC is enabled. p_msg->len will be 2 if
588 * PEC is enabled, otherwise 1.
589 */
590 if (id->p_msg->flags & I2C_M_RECV_LEN)
591 id->recv_count = I2C_SMBUS_BLOCK_MAX + id->p_msg->len;
592
593 id->curr_recv_count = id->recv_count;
594
595 /*
596 * Check for the message size against FIFO depth and set the
597 * 'hold bus' bit if it is greater than FIFO depth.
598 */
599 if (id->recv_count > id->fifo_depth)
600 ctrl_reg |= CDNS_I2C_CR_HOLD;
601
602 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
603
604 /* Clear the interrupts in interrupt status register */
605 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
606 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
607
608 /*
609 * The no. of bytes to receive is checked against the limit of
610 * max transfer size. Set transfer size register with no of bytes
611 * receive if it is less than transfer size and transfer size if
612 * it is more. Enable the interrupts.
613 */
614 if (id->recv_count > id->transfer_size) {
615 cdns_i2c_writereg(id->transfer_size,
616 CDNS_I2C_XFER_SIZE_OFFSET);
617 id->curr_recv_count = id->transfer_size;
618 } else {
619 cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET);
620 }
621
622 /* Determine hold_clear based on number of bytes to receive and hold flag */
623 if (!id->bus_hold_flag && id->recv_count <= id->fifo_depth) {
624 if (ctrl_reg & CDNS_I2C_CR_HOLD) {
625 hold_clear = true;
626 if (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT)
627 irq_save = true;
628 }
629 }
630
631 addr = id->p_msg->addr;
632 addr &= CDNS_I2C_ADDR_MASK;
633
634 if (hold_clear) {
635 ctrl_reg &= ~CDNS_I2C_CR_HOLD;
636 /*
637 * In case of Xilinx Zynq SOC, clear the HOLD bit before transfer size
638 * register reaches '0'. This is an IP bug which causes transfer size
639 * register overflow to 0xFF. To satisfy this timing requirement,
640 * disable the interrupts on current processor core between register
641 * writes to slave address register and control register.
642 */
643 if (irq_save)
644 local_irq_save(flags);
645
646 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET);
647 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
648 /* Read it back to avoid bufferring and make sure write happens */
649 cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
650
651 if (irq_save)
652 local_irq_restore(flags);
653 } else {
654 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET);
655 }
656
657 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET);
658 }
659
660 /**
661 * cdns_i2c_msend - Prepare and start a master send operation
662 * @id: pointer to the i2c device
663 */
cdns_i2c_msend(struct cdns_i2c * id)664 static void cdns_i2c_msend(struct cdns_i2c *id)
665 {
666 unsigned int avail_bytes;
667 unsigned int bytes_to_send;
668 unsigned int ctrl_reg;
669 unsigned int isr_status;
670
671 id->p_recv_buf = NULL;
672 id->p_send_buf = id->p_msg->buf;
673 id->send_count = id->p_msg->len;
674
675 /* Set the controller in Master transmit mode and clear the FIFO. */
676 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
677 ctrl_reg &= ~CDNS_I2C_CR_RW;
678 ctrl_reg |= CDNS_I2C_CR_CLR_FIFO;
679
680 /*
681 * Check for the message size against FIFO depth and set the
682 * 'hold bus' bit if it is greater than FIFO depth.
683 */
684 if (id->send_count > id->fifo_depth)
685 ctrl_reg |= CDNS_I2C_CR_HOLD;
686 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
687
688 /* Clear the interrupts in interrupt status register. */
689 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
690 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
691
692 /*
693 * Calculate the space available in FIFO. Check the message length
694 * against the space available, and fill the FIFO accordingly.
695 * Enable the interrupts.
696 */
697 avail_bytes = id->fifo_depth -
698 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
699
700 if (id->send_count > avail_bytes)
701 bytes_to_send = avail_bytes;
702 else
703 bytes_to_send = id->send_count;
704
705 while (bytes_to_send--) {
706 cdns_i2c_writereg((*(id->p_send_buf)++), CDNS_I2C_DATA_OFFSET);
707 id->send_count--;
708 }
709
710 /*
711 * Clear the bus hold flag if there is no more data
712 * and if it is the last message.
713 */
714 if (!id->bus_hold_flag && !id->send_count)
715 cdns_i2c_clear_bus_hold(id);
716 /* Set the slave address in address register - triggers operation. */
717 cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK,
718 CDNS_I2C_ADDR_OFFSET);
719
720 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET);
721 }
722
723 /**
724 * cdns_i2c_master_reset - Reset the interface
725 * @adap: pointer to the i2c adapter driver instance
726 *
727 * This function cleanup the fifos, clear the hold bit and status
728 * and disable the interrupts.
729 */
cdns_i2c_master_reset(struct i2c_adapter * adap)730 static void cdns_i2c_master_reset(struct i2c_adapter *adap)
731 {
732 struct cdns_i2c *id = adap->algo_data;
733 u32 regval;
734
735 /* Disable the interrupts */
736 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET);
737 /* Clear the hold bit and fifos */
738 regval = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
739 regval &= ~CDNS_I2C_CR_HOLD;
740 regval |= CDNS_I2C_CR_CLR_FIFO;
741 cdns_i2c_writereg(regval, CDNS_I2C_CR_OFFSET);
742 /* Update the transfercount register to zero */
743 cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET);
744 /* Clear the interrupt status register */
745 regval = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
746 cdns_i2c_writereg(regval, CDNS_I2C_ISR_OFFSET);
747 /* Clear the status register */
748 regval = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET);
749 cdns_i2c_writereg(regval, CDNS_I2C_SR_OFFSET);
750 }
751
cdns_i2c_process_msg(struct cdns_i2c * id,struct i2c_msg * msg,struct i2c_adapter * adap)752 static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg,
753 struct i2c_adapter *adap)
754 {
755 unsigned long time_left, msg_timeout;
756 u32 reg;
757
758 id->p_msg = msg;
759 id->err_status = 0;
760 reinit_completion(&id->xfer_done);
761
762 /* Check for the TEN Bit mode on each msg */
763 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
764 if (msg->flags & I2C_M_TEN) {
765 if (reg & CDNS_I2C_CR_NEA)
766 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_NEA,
767 CDNS_I2C_CR_OFFSET);
768 } else {
769 if (!(reg & CDNS_I2C_CR_NEA))
770 cdns_i2c_writereg(reg | CDNS_I2C_CR_NEA,
771 CDNS_I2C_CR_OFFSET);
772 }
773
774 /* Check for the R/W flag on each msg */
775 if (msg->flags & I2C_M_RD)
776 cdns_i2c_mrecv(id);
777 else
778 cdns_i2c_msend(id);
779
780 /* Minimal time to execute this message */
781 msg_timeout = msecs_to_jiffies((1000 * msg->len * BITS_PER_BYTE) / id->i2c_clk);
782 /* Plus some wiggle room */
783 msg_timeout += msecs_to_jiffies(500);
784
785 if (msg_timeout < adap->timeout)
786 msg_timeout = adap->timeout;
787
788 /* Wait for the signal of completion */
789 time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout);
790 if (time_left == 0) {
791 cdns_i2c_master_reset(adap);
792 dev_err(id->adap.dev.parent,
793 "timeout waiting on completion\n");
794 return -ETIMEDOUT;
795 }
796
797 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK,
798 CDNS_I2C_IDR_OFFSET);
799
800 /* If it is bus arbitration error, try again */
801 if (id->err_status & CDNS_I2C_IXR_ARB_LOST)
802 return -EAGAIN;
803
804 if (msg->flags & I2C_M_RECV_LEN)
805 msg->len += min_t(unsigned int, msg->buf[0], I2C_SMBUS_BLOCK_MAX);
806
807 return 0;
808 }
809
810 /**
811 * cdns_i2c_master_xfer - The main i2c transfer function
812 * @adap: pointer to the i2c adapter driver instance
813 * @msgs: pointer to the i2c message structure
814 * @num: the number of messages to transfer
815 *
816 * Initiates the send/recv activity based on the transfer message received.
817 *
818 * Return: number of msgs processed on success, negative error otherwise
819 */
cdns_i2c_master_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)820 static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
821 int num)
822 {
823 int ret, count;
824 u32 reg;
825 struct cdns_i2c *id = adap->algo_data;
826 bool hold_quirk;
827 #if IS_ENABLED(CONFIG_I2C_SLAVE)
828 bool change_role = false;
829 #endif
830
831 ret = pm_runtime_resume_and_get(id->dev);
832 if (ret < 0)
833 return ret;
834
835 #if IS_ENABLED(CONFIG_I2C_SLAVE)
836 /* Check i2c operating mode and switch if possible */
837 if (id->dev_mode == CDNS_I2C_MODE_SLAVE) {
838 if (id->slave_state != CDNS_I2C_SLAVE_STATE_IDLE) {
839 ret = -EAGAIN;
840 goto out;
841 }
842
843 /* Set mode to master */
844 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id);
845
846 /* Mark flag to change role once xfer is completed */
847 change_role = true;
848 }
849 #endif
850
851 /* Check if the bus is free */
852
853 ret = readl_relaxed_poll_timeout(id->membase + CDNS_I2C_SR_OFFSET,
854 reg,
855 !(reg & CDNS_I2C_SR_BA),
856 CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US);
857 if (ret) {
858 ret = -EAGAIN;
859 if (id->adap.bus_recovery_info)
860 i2c_recover_bus(adap);
861 goto out;
862 }
863
864 hold_quirk = !!(id->quirks & CDNS_I2C_BROKEN_HOLD_BIT);
865 /*
866 * Set the flag to one when multiple messages are to be
867 * processed with a repeated start.
868 */
869 if (num > 1) {
870 /*
871 * This controller does not give completion interrupt after a
872 * master receive message if HOLD bit is set (repeated start),
873 * resulting in SW timeout. Hence, if a receive message is
874 * followed by any other message, an error is returned
875 * indicating that this sequence is not supported.
876 */
877 for (count = 0; (count < num - 1 && hold_quirk); count++) {
878 if (msgs[count].flags & I2C_M_RD) {
879 dev_warn(adap->dev.parent,
880 "Can't do repeated start after a receive message\n");
881 ret = -EOPNOTSUPP;
882 goto out;
883 }
884 }
885 id->bus_hold_flag = 1;
886 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
887 reg |= CDNS_I2C_CR_HOLD;
888 cdns_i2c_writereg(reg, CDNS_I2C_CR_OFFSET);
889 } else {
890 id->bus_hold_flag = 0;
891 }
892
893 /* Process the msg one by one */
894 for (count = 0; count < num; count++, msgs++) {
895 if (count == (num - 1))
896 id->bus_hold_flag = 0;
897
898 ret = cdns_i2c_process_msg(id, msgs, adap);
899 if (ret)
900 goto out;
901
902 /* Report the other error interrupts to application */
903 if (id->err_status) {
904 cdns_i2c_master_reset(adap);
905
906 if (id->err_status & CDNS_I2C_IXR_NACK) {
907 ret = -ENXIO;
908 goto out;
909 }
910 ret = -EIO;
911 goto out;
912 }
913 }
914
915 ret = num;
916
917 out:
918
919 #if IS_ENABLED(CONFIG_I2C_SLAVE)
920 /* Switch i2c mode to slave */
921 if (change_role)
922 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id);
923 #endif
924
925 pm_runtime_mark_last_busy(id->dev);
926 pm_runtime_put_autosuspend(id->dev);
927 return ret;
928 }
929
930 /**
931 * cdns_i2c_func - Returns the supported features of the I2C driver
932 * @adap: pointer to the i2c adapter structure
933 *
934 * Return: 32 bit value, each bit corresponding to a feature
935 */
cdns_i2c_func(struct i2c_adapter * adap)936 static u32 cdns_i2c_func(struct i2c_adapter *adap)
937 {
938 u32 func = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
939 (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
940 I2C_FUNC_SMBUS_BLOCK_DATA;
941
942 #if IS_ENABLED(CONFIG_I2C_SLAVE)
943 func |= I2C_FUNC_SLAVE;
944 #endif
945
946 return func;
947 }
948
949 #if IS_ENABLED(CONFIG_I2C_SLAVE)
cdns_reg_slave(struct i2c_client * slave)950 static int cdns_reg_slave(struct i2c_client *slave)
951 {
952 int ret;
953 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c,
954 adap);
955
956 if (id->slave)
957 return -EBUSY;
958
959 if (slave->flags & I2C_CLIENT_TEN)
960 return -EAFNOSUPPORT;
961
962 ret = pm_runtime_resume_and_get(id->dev);
963 if (ret < 0)
964 return ret;
965
966 /* Store slave information */
967 id->slave = slave;
968
969 /* Enable I2C slave */
970 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id);
971
972 return 0;
973 }
974
cdns_unreg_slave(struct i2c_client * slave)975 static int cdns_unreg_slave(struct i2c_client *slave)
976 {
977 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c,
978 adap);
979
980 pm_runtime_put(id->dev);
981
982 /* Remove slave information */
983 id->slave = NULL;
984
985 /* Enable I2C master */
986 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id);
987
988 return 0;
989 }
990 #endif
991
992 static const struct i2c_algorithm cdns_i2c_algo = {
993 .master_xfer = cdns_i2c_master_xfer,
994 .functionality = cdns_i2c_func,
995 #if IS_ENABLED(CONFIG_I2C_SLAVE)
996 .reg_slave = cdns_reg_slave,
997 .unreg_slave = cdns_unreg_slave,
998 #endif
999 };
1000
1001 /**
1002 * cdns_i2c_calc_divs - Calculate clock dividers
1003 * @f: I2C clock frequency
1004 * @input_clk: Input clock frequency
1005 * @a: First divider (return value)
1006 * @b: Second divider (return value)
1007 *
1008 * f is used as input and output variable. As input it is used as target I2C
1009 * frequency. On function exit f holds the actually resulting I2C frequency.
1010 *
1011 * Return: 0 on success, negative errno otherwise.
1012 */
cdns_i2c_calc_divs(unsigned long * f,unsigned long input_clk,unsigned int * a,unsigned int * b)1013 static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk,
1014 unsigned int *a, unsigned int *b)
1015 {
1016 unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp;
1017 unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0;
1018 unsigned int last_error, current_error;
1019
1020 /* calculate (divisor_a+1) x (divisor_b+1) */
1021 temp = input_clk / (22 * fscl);
1022
1023 /*
1024 * If the calculated value is negative or 0, the fscl input is out of
1025 * range. Return error.
1026 */
1027 if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX)))
1028 return -EINVAL;
1029
1030 last_error = -1;
1031 for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) {
1032 div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1));
1033
1034 if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX))
1035 continue;
1036 div_b--;
1037
1038 actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1));
1039
1040 if (actual_fscl > fscl)
1041 continue;
1042
1043 current_error = fscl - actual_fscl;
1044
1045 if (last_error > current_error) {
1046 calc_div_a = div_a;
1047 calc_div_b = div_b;
1048 best_fscl = actual_fscl;
1049 last_error = current_error;
1050 }
1051 }
1052
1053 *a = calc_div_a;
1054 *b = calc_div_b;
1055 *f = best_fscl;
1056
1057 return 0;
1058 }
1059
1060 /**
1061 * cdns_i2c_setclk - This function sets the serial clock rate for the I2C device
1062 * @clk_in: I2C clock input frequency in Hz
1063 * @id: Pointer to the I2C device structure
1064 *
1065 * The device must be idle rather than busy transferring data before setting
1066 * these device options.
1067 * The data rate is set by values in the control register.
1068 * The formula for determining the correct register values is
1069 * Fscl = Fpclk/(22 x (divisor_a+1) x (divisor_b+1))
1070 * See the hardware data sheet for a full explanation of setting the serial
1071 * clock rate. The clock can not be faster than the input clock divide by 22.
1072 * The two most common clock rates are 100KHz and 400KHz.
1073 *
1074 * Return: 0 on success, negative error otherwise
1075 */
cdns_i2c_setclk(unsigned long clk_in,struct cdns_i2c * id)1076 static int cdns_i2c_setclk(unsigned long clk_in, struct cdns_i2c *id)
1077 {
1078 unsigned int div_a, div_b;
1079 unsigned int ctrl_reg;
1080 int ret = 0;
1081 unsigned long fscl = id->i2c_clk;
1082
1083 ret = cdns_i2c_calc_divs(&fscl, clk_in, &div_a, &div_b);
1084 if (ret)
1085 return ret;
1086
1087 ctrl_reg = id->ctrl_reg;
1088 ctrl_reg &= ~(CDNS_I2C_CR_DIVA_MASK | CDNS_I2C_CR_DIVB_MASK);
1089 ctrl_reg |= ((div_a << CDNS_I2C_CR_DIVA_SHIFT) |
1090 (div_b << CDNS_I2C_CR_DIVB_SHIFT));
1091 id->ctrl_reg = ctrl_reg;
1092 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
1093 #if IS_ENABLED(CONFIG_I2C_SLAVE)
1094 id->ctrl_reg_diva_divb = ctrl_reg & (CDNS_I2C_CR_DIVA_MASK |
1095 CDNS_I2C_CR_DIVB_MASK);
1096 #endif
1097 return 0;
1098 }
1099
1100 /**
1101 * cdns_i2c_clk_notifier_cb - Clock rate change callback
1102 * @nb: Pointer to notifier block
1103 * @event: Notification reason
1104 * @data: Pointer to notification data object
1105 *
1106 * This function is called when the cdns_i2c input clock frequency changes.
1107 * The callback checks whether a valid bus frequency can be generated after the
1108 * change. If so, the change is acknowledged, otherwise the change is aborted.
1109 * New dividers are written to the HW in the pre- or post change notification
1110 * depending on the scaling direction.
1111 *
1112 * Return: NOTIFY_STOP if the rate change should be aborted, NOTIFY_OK
1113 * to acknowledge the change, NOTIFY_DONE if the notification is
1114 * considered irrelevant.
1115 */
cdns_i2c_clk_notifier_cb(struct notifier_block * nb,unsigned long event,void * data)1116 static int cdns_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
1117 event, void *data)
1118 {
1119 struct clk_notifier_data *ndata = data;
1120 struct cdns_i2c *id = to_cdns_i2c(nb);
1121
1122 if (pm_runtime_suspended(id->dev))
1123 return NOTIFY_OK;
1124
1125 switch (event) {
1126 case PRE_RATE_CHANGE:
1127 {
1128 unsigned long input_clk = ndata->new_rate;
1129 unsigned long fscl = id->i2c_clk;
1130 unsigned int div_a, div_b;
1131 int ret;
1132
1133 ret = cdns_i2c_calc_divs(&fscl, input_clk, &div_a, &div_b);
1134 if (ret) {
1135 dev_warn(id->adap.dev.parent,
1136 "clock rate change rejected\n");
1137 return NOTIFY_STOP;
1138 }
1139
1140 /* scale up */
1141 if (ndata->new_rate > ndata->old_rate)
1142 cdns_i2c_setclk(ndata->new_rate, id);
1143
1144 return NOTIFY_OK;
1145 }
1146 case POST_RATE_CHANGE:
1147 id->input_clk = ndata->new_rate;
1148 /* scale down */
1149 if (ndata->new_rate < ndata->old_rate)
1150 cdns_i2c_setclk(ndata->new_rate, id);
1151 return NOTIFY_OK;
1152 case ABORT_RATE_CHANGE:
1153 /* scale up */
1154 if (ndata->new_rate > ndata->old_rate)
1155 cdns_i2c_setclk(ndata->old_rate, id);
1156 return NOTIFY_OK;
1157 default:
1158 return NOTIFY_DONE;
1159 }
1160 }
1161
1162 /**
1163 * cdns_i2c_runtime_suspend - Runtime suspend method for the driver
1164 * @dev: Address of the platform_device structure
1165 *
1166 * Put the driver into low power mode.
1167 *
1168 * Return: 0 always
1169 */
cdns_i2c_runtime_suspend(struct device * dev)1170 static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev)
1171 {
1172 struct cdns_i2c *xi2c = dev_get_drvdata(dev);
1173
1174 clk_disable(xi2c->clk);
1175
1176 return 0;
1177 }
1178
1179 /**
1180 * cdns_i2c_init - Controller initialisation
1181 * @id: Device private data structure
1182 *
1183 * Initialise the i2c controller.
1184 *
1185 */
cdns_i2c_init(struct cdns_i2c * id)1186 static void cdns_i2c_init(struct cdns_i2c *id)
1187 {
1188 cdns_i2c_writereg(id->ctrl_reg, CDNS_I2C_CR_OFFSET);
1189 /*
1190 * Cadence I2C controller has a bug wherein it generates
1191 * invalid read transaction after HW timeout in master receiver mode.
1192 * HW timeout is not used by this driver and the interrupt is disabled.
1193 * But the feature itself cannot be disabled. Hence maximum value
1194 * is written to this register to reduce the chances of error.
1195 */
1196 cdns_i2c_writereg(CDNS_I2C_TIMEOUT_MAX, CDNS_I2C_TIME_OUT_OFFSET);
1197 }
1198
1199 /**
1200 * cdns_i2c_runtime_resume - Runtime resume
1201 * @dev: Address of the platform_device structure
1202 *
1203 * Runtime resume callback.
1204 *
1205 * Return: 0 on success and error value on error
1206 */
cdns_i2c_runtime_resume(struct device * dev)1207 static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev)
1208 {
1209 struct cdns_i2c *xi2c = dev_get_drvdata(dev);
1210 int ret;
1211
1212 ret = clk_enable(xi2c->clk);
1213 if (ret) {
1214 dev_err(dev, "Cannot enable clock.\n");
1215 return ret;
1216 }
1217 cdns_i2c_init(xi2c);
1218
1219 return 0;
1220 }
1221
1222 static const struct dev_pm_ops cdns_i2c_dev_pm_ops = {
1223 SET_RUNTIME_PM_OPS(cdns_i2c_runtime_suspend,
1224 cdns_i2c_runtime_resume, NULL)
1225 };
1226
1227 static const struct cdns_platform_data r1p10_i2c_def = {
1228 .quirks = CDNS_I2C_BROKEN_HOLD_BIT,
1229 };
1230
1231 static const struct of_device_id cdns_i2c_of_match[] = {
1232 { .compatible = "cdns,i2c-r1p10", .data = &r1p10_i2c_def },
1233 { .compatible = "cdns,i2c-r1p14",},
1234 { /* end of table */ }
1235 };
1236 MODULE_DEVICE_TABLE(of, cdns_i2c_of_match);
1237
1238 /**
1239 * cdns_i2c_detect_transfer_size - Detect the maximum transfer size supported
1240 * @id: Device private data structure
1241 *
1242 * Detect the maximum transfer size that is supported by this instance of the
1243 * Cadence I2C controller.
1244 */
cdns_i2c_detect_transfer_size(struct cdns_i2c * id)1245 static void cdns_i2c_detect_transfer_size(struct cdns_i2c *id)
1246 {
1247 u32 val;
1248
1249 /*
1250 * Writing to the transfer size register is only possible if these two bits
1251 * are set in the control register.
1252 */
1253 cdns_i2c_writereg(CDNS_I2C_CR_MS | CDNS_I2C_CR_RW, CDNS_I2C_CR_OFFSET);
1254
1255 /*
1256 * The number of writable bits of the transfer size register can be between
1257 * 4 and 8. This is a controlled through a synthesis parameter of the IP
1258 * core and can vary from instance to instance. The unused MSBs always read
1259 * back as 0. Writing 0xff and then reading the value back will report the
1260 * maximum supported transfer size.
1261 */
1262 cdns_i2c_writereg(CDNS_I2C_MAX_TRANSFER_SIZE, CDNS_I2C_XFER_SIZE_OFFSET);
1263 val = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
1264 id->transfer_size = CDNS_I2C_TRANSFER_SIZE(val);
1265 cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET);
1266 cdns_i2c_writereg(0, CDNS_I2C_CR_OFFSET);
1267 }
1268
1269 /**
1270 * cdns_i2c_probe - Platform registration call
1271 * @pdev: Handle to the platform device structure
1272 *
1273 * This function does all the memory allocation and registration for the i2c
1274 * device. User can modify the address mode to 10 bit address mode using the
1275 * ioctl call with option I2C_TENBIT.
1276 *
1277 * Return: 0 on success, negative error otherwise
1278 */
cdns_i2c_probe(struct platform_device * pdev)1279 static int cdns_i2c_probe(struct platform_device *pdev)
1280 {
1281 struct resource *r_mem;
1282 struct cdns_i2c *id;
1283 int ret, irq;
1284 const struct of_device_id *match;
1285
1286 id = devm_kzalloc(&pdev->dev, sizeof(*id), GFP_KERNEL);
1287 if (!id)
1288 return -ENOMEM;
1289
1290 id->dev = &pdev->dev;
1291 platform_set_drvdata(pdev, id);
1292
1293 match = of_match_node(cdns_i2c_of_match, pdev->dev.of_node);
1294 if (match && match->data) {
1295 const struct cdns_platform_data *data = match->data;
1296 id->quirks = data->quirks;
1297 }
1298
1299 id->rinfo.pinctrl = devm_pinctrl_get(&pdev->dev);
1300 if (IS_ERR(id->rinfo.pinctrl)) {
1301 int err = PTR_ERR(id->rinfo.pinctrl);
1302
1303 dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
1304 if (err != -ENODEV)
1305 return err;
1306 } else {
1307 id->adap.bus_recovery_info = &id->rinfo;
1308 }
1309
1310 id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem);
1311 if (IS_ERR(id->membase))
1312 return PTR_ERR(id->membase);
1313
1314 irq = platform_get_irq(pdev, 0);
1315 if (irq < 0)
1316 return irq;
1317
1318 id->adap.owner = THIS_MODULE;
1319 id->adap.dev.of_node = pdev->dev.of_node;
1320 id->adap.algo = &cdns_i2c_algo;
1321 id->adap.timeout = CDNS_I2C_TIMEOUT;
1322 id->adap.retries = 3; /* Default retry value. */
1323 id->adap.algo_data = id;
1324 id->adap.dev.parent = &pdev->dev;
1325 init_completion(&id->xfer_done);
1326 snprintf(id->adap.name, sizeof(id->adap.name),
1327 "Cadence I2C at %08lx", (unsigned long)r_mem->start);
1328
1329 id->clk = devm_clk_get(&pdev->dev, NULL);
1330 if (IS_ERR(id->clk))
1331 return dev_err_probe(&pdev->dev, PTR_ERR(id->clk),
1332 "input clock not found.\n");
1333
1334 id->reset = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
1335 if (IS_ERR(id->reset))
1336 return dev_err_probe(&pdev->dev, PTR_ERR(id->reset),
1337 "Failed to request reset.\n");
1338
1339 ret = clk_prepare_enable(id->clk);
1340 if (ret)
1341 dev_err(&pdev->dev, "Unable to enable clock.\n");
1342
1343 ret = reset_control_deassert(id->reset);
1344 if (ret) {
1345 dev_err_probe(&pdev->dev, ret,
1346 "Failed to de-assert reset.\n");
1347 goto err_clk_dis;
1348 }
1349
1350 pm_runtime_set_autosuspend_delay(id->dev, CNDS_I2C_PM_TIMEOUT);
1351 pm_runtime_use_autosuspend(id->dev);
1352 pm_runtime_set_active(id->dev);
1353 pm_runtime_enable(id->dev);
1354
1355 id->clk_rate_change_nb.notifier_call = cdns_i2c_clk_notifier_cb;
1356 if (clk_notifier_register(id->clk, &id->clk_rate_change_nb))
1357 dev_warn(&pdev->dev, "Unable to register clock notifier.\n");
1358 id->input_clk = clk_get_rate(id->clk);
1359
1360 ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
1361 &id->i2c_clk);
1362 if (ret || (id->i2c_clk > I2C_MAX_FAST_MODE_FREQ))
1363 id->i2c_clk = I2C_MAX_STANDARD_MODE_FREQ;
1364
1365 #if IS_ENABLED(CONFIG_I2C_SLAVE)
1366 /* Set initial mode to master */
1367 id->dev_mode = CDNS_I2C_MODE_MASTER;
1368 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
1369 #endif
1370 id->ctrl_reg = CDNS_I2C_CR_ACK_EN | CDNS_I2C_CR_NEA | CDNS_I2C_CR_MS;
1371
1372 id->fifo_depth = CDNS_I2C_FIFO_DEPTH_DEFAULT;
1373 of_property_read_u32(pdev->dev.of_node, "fifo-depth", &id->fifo_depth);
1374
1375 cdns_i2c_detect_transfer_size(id);
1376
1377 ret = cdns_i2c_setclk(id->input_clk, id);
1378 if (ret) {
1379 dev_err(&pdev->dev, "invalid SCL clock: %u Hz\n", id->i2c_clk);
1380 ret = -EINVAL;
1381 goto err_clk_notifier_unregister;
1382 }
1383
1384 ret = devm_request_irq(&pdev->dev, irq, cdns_i2c_isr, 0,
1385 DRIVER_NAME, id);
1386 if (ret) {
1387 dev_err(&pdev->dev, "cannot get irq %d\n", irq);
1388 goto err_clk_notifier_unregister;
1389 }
1390 cdns_i2c_init(id);
1391
1392 ret = i2c_add_adapter(&id->adap);
1393 if (ret < 0)
1394 goto err_clk_notifier_unregister;
1395
1396 dev_info(&pdev->dev, "%u kHz mmio %08lx irq %d\n",
1397 id->i2c_clk / 1000, (unsigned long)r_mem->start, irq);
1398
1399 return 0;
1400
1401 err_clk_notifier_unregister:
1402 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
1403 reset_control_assert(id->reset);
1404 err_clk_dis:
1405 clk_disable_unprepare(id->clk);
1406 pm_runtime_disable(&pdev->dev);
1407 pm_runtime_set_suspended(&pdev->dev);
1408 return ret;
1409 }
1410
1411 /**
1412 * cdns_i2c_remove - Unregister the device after releasing the resources
1413 * @pdev: Handle to the platform device structure
1414 *
1415 * This function frees all the resources allocated to the device.
1416 *
1417 * Return: 0 always
1418 */
cdns_i2c_remove(struct platform_device * pdev)1419 static void cdns_i2c_remove(struct platform_device *pdev)
1420 {
1421 struct cdns_i2c *id = platform_get_drvdata(pdev);
1422
1423 pm_runtime_disable(&pdev->dev);
1424 pm_runtime_set_suspended(&pdev->dev);
1425 pm_runtime_dont_use_autosuspend(&pdev->dev);
1426
1427 i2c_del_adapter(&id->adap);
1428 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
1429 reset_control_assert(id->reset);
1430 clk_disable_unprepare(id->clk);
1431 }
1432
1433 static struct platform_driver cdns_i2c_drv = {
1434 .driver = {
1435 .name = DRIVER_NAME,
1436 .of_match_table = cdns_i2c_of_match,
1437 .pm = &cdns_i2c_dev_pm_ops,
1438 },
1439 .probe = cdns_i2c_probe,
1440 .remove_new = cdns_i2c_remove,
1441 };
1442
1443 module_platform_driver(cdns_i2c_drv);
1444
1445 MODULE_AUTHOR("Xilinx Inc.");
1446 MODULE_DESCRIPTION("Cadence I2C bus driver");
1447 MODULE_LICENSE("GPL");
1448