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
20 /* Register offsets for the I2C device. */
21 #define CDNS_I2C_CR_OFFSET 0x00 /* Control Register, RW */
22 #define CDNS_I2C_SR_OFFSET 0x04 /* Status Register, RO */
23 #define CDNS_I2C_ADDR_OFFSET 0x08 /* I2C Address Register, RW */
24 #define CDNS_I2C_DATA_OFFSET 0x0C /* I2C Data Register, RW */
25 #define CDNS_I2C_ISR_OFFSET 0x10 /* IRQ Status Register, RW */
26 #define CDNS_I2C_XFER_SIZE_OFFSET 0x14 /* Transfer Size Register, RW */
27 #define CDNS_I2C_TIME_OUT_OFFSET 0x1C /* Time Out Register, RW */
28 #define CDNS_I2C_IMR_OFFSET 0x20 /* IRQ Mask Register, RO */
29 #define CDNS_I2C_IER_OFFSET 0x24 /* IRQ Enable Register, WO */
30 #define CDNS_I2C_IDR_OFFSET 0x28 /* IRQ Disable Register, WO */
31
32 /* Control Register Bit mask definitions */
33 #define CDNS_I2C_CR_HOLD BIT(4) /* Hold Bus bit */
34 #define CDNS_I2C_CR_ACK_EN BIT(3)
35 #define CDNS_I2C_CR_NEA BIT(2)
36 #define CDNS_I2C_CR_MS BIT(1)
37 /* Read or Write Master transfer 0 = Transmitter, 1 = Receiver */
38 #define CDNS_I2C_CR_RW BIT(0)
39 /* 1 = Auto init FIFO to zeroes */
40 #define CDNS_I2C_CR_CLR_FIFO BIT(6)
41 #define CDNS_I2C_CR_DIVA_SHIFT 14
42 #define CDNS_I2C_CR_DIVA_MASK (3 << CDNS_I2C_CR_DIVA_SHIFT)
43 #define CDNS_I2C_CR_DIVB_SHIFT 8
44 #define CDNS_I2C_CR_DIVB_MASK (0x3f << CDNS_I2C_CR_DIVB_SHIFT)
45
46 #define CDNS_I2C_CR_MASTER_EN_MASK (CDNS_I2C_CR_NEA | \
47 CDNS_I2C_CR_ACK_EN | \
48 CDNS_I2C_CR_MS)
49
50 #define CDNS_I2C_CR_SLAVE_EN_MASK ~CDNS_I2C_CR_MASTER_EN_MASK
51
52 /* Status Register Bit mask definitions */
53 #define CDNS_I2C_SR_BA BIT(8)
54 #define CDNS_I2C_SR_TXDV BIT(6)
55 #define CDNS_I2C_SR_RXDV BIT(5)
56 #define CDNS_I2C_SR_RXRW BIT(3)
57
58 /*
59 * I2C Address Register Bit mask definitions
60 * Normal addressing mode uses [6:0] bits. Extended addressing mode uses [9:0]
61 * bits. A write access to this register always initiates a transfer if the I2C
62 * is in master mode.
63 */
64 #define CDNS_I2C_ADDR_MASK 0x000003FF /* I2C Address Mask */
65
66 /*
67 * I2C Interrupt Registers Bit mask definitions
68 * All the four interrupt registers (Status/Mask/Enable/Disable) have the same
69 * bit definitions.
70 */
71 #define CDNS_I2C_IXR_ARB_LOST BIT(9)
72 #define CDNS_I2C_IXR_RX_UNF BIT(7)
73 #define CDNS_I2C_IXR_TX_OVF BIT(6)
74 #define CDNS_I2C_IXR_RX_OVF BIT(5)
75 #define CDNS_I2C_IXR_SLV_RDY BIT(4)
76 #define CDNS_I2C_IXR_TO BIT(3)
77 #define CDNS_I2C_IXR_NACK BIT(2)
78 #define CDNS_I2C_IXR_DATA BIT(1)
79 #define CDNS_I2C_IXR_COMP BIT(0)
80
81 #define CDNS_I2C_IXR_ALL_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
82 CDNS_I2C_IXR_RX_UNF | \
83 CDNS_I2C_IXR_TX_OVF | \
84 CDNS_I2C_IXR_RX_OVF | \
85 CDNS_I2C_IXR_SLV_RDY | \
86 CDNS_I2C_IXR_TO | \
87 CDNS_I2C_IXR_NACK | \
88 CDNS_I2C_IXR_DATA | \
89 CDNS_I2C_IXR_COMP)
90
91 #define CDNS_I2C_IXR_ERR_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
92 CDNS_I2C_IXR_RX_UNF | \
93 CDNS_I2C_IXR_TX_OVF | \
94 CDNS_I2C_IXR_RX_OVF | \
95 CDNS_I2C_IXR_NACK)
96
97 #define CDNS_I2C_ENABLED_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
98 CDNS_I2C_IXR_RX_UNF | \
99 CDNS_I2C_IXR_TX_OVF | \
100 CDNS_I2C_IXR_RX_OVF | \
101 CDNS_I2C_IXR_NACK | \
102 CDNS_I2C_IXR_DATA | \
103 CDNS_I2C_IXR_COMP)
104
105 #define CDNS_I2C_IXR_SLAVE_INTR_MASK (CDNS_I2C_IXR_RX_UNF | \
106 CDNS_I2C_IXR_TX_OVF | \
107 CDNS_I2C_IXR_RX_OVF | \
108 CDNS_I2C_IXR_TO | \
109 CDNS_I2C_IXR_NACK | \
110 CDNS_I2C_IXR_DATA | \
111 CDNS_I2C_IXR_COMP)
112
113 #define CDNS_I2C_TIMEOUT msecs_to_jiffies(1000)
114 /* timeout for pm runtime autosuspend */
115 #define CNDS_I2C_PM_TIMEOUT 1000 /* ms */
116
117 #define CDNS_I2C_FIFO_DEPTH 16
118 /* FIFO depth at which the DATA interrupt occurs */
119 #define CDNS_I2C_DATA_INTR_DEPTH (CDNS_I2C_FIFO_DEPTH - 2)
120 #define CDNS_I2C_MAX_TRANSFER_SIZE 255
121 /* Transfer size in multiples of data interrupt depth */
122 #define CDNS_I2C_TRANSFER_SIZE (CDNS_I2C_MAX_TRANSFER_SIZE - 3)
123
124 #define DRIVER_NAME "cdns-i2c"
125
126 #define CDNS_I2C_DIVA_MAX 4
127 #define CDNS_I2C_DIVB_MAX 64
128
129 #define CDNS_I2C_TIMEOUT_MAX 0xFF
130
131 #define CDNS_I2C_BROKEN_HOLD_BIT BIT(0)
132 #define CDNS_I2C_POLL_US 100000
133 #define CDNS_I2C_TIMEOUT_US 500000
134
135 #define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset)
136 #define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset)
137
138 #if IS_ENABLED(CONFIG_I2C_SLAVE)
139 /**
140 * enum cdns_i2c_mode - I2C Controller current operating mode
141 *
142 * @CDNS_I2C_MODE_SLAVE: I2C controller operating in slave mode
143 * @CDNS_I2C_MODE_MASTER: I2C Controller operating in master mode
144 */
145 enum cdns_i2c_mode {
146 CDNS_I2C_MODE_SLAVE,
147 CDNS_I2C_MODE_MASTER,
148 };
149
150 /**
151 * enum cdns_i2c_slave_state - Slave state when I2C is operating in slave mode
152 *
153 * @CDNS_I2C_SLAVE_STATE_IDLE: I2C slave idle
154 * @CDNS_I2C_SLAVE_STATE_SEND: I2C slave sending data to master
155 * @CDNS_I2C_SLAVE_STATE_RECV: I2C slave receiving data from master
156 */
157 enum cdns_i2c_slave_state {
158 CDNS_I2C_SLAVE_STATE_IDLE,
159 CDNS_I2C_SLAVE_STATE_SEND,
160 CDNS_I2C_SLAVE_STATE_RECV,
161 };
162 #endif
163
164 /**
165 * struct cdns_i2c - I2C device private data structure
166 *
167 * @dev: Pointer to device structure
168 * @membase: Base address of the I2C device
169 * @adap: I2C adapter instance
170 * @p_msg: Message pointer
171 * @err_status: Error status in Interrupt Status Register
172 * @xfer_done: Transfer complete status
173 * @p_send_buf: Pointer to transmit buffer
174 * @p_recv_buf: Pointer to receive buffer
175 * @send_count: Number of bytes still expected to send
176 * @recv_count: Number of bytes still expected to receive
177 * @curr_recv_count: Number of bytes to be received in current transfer
178 * @irq: IRQ number
179 * @input_clk: Input clock to I2C controller
180 * @i2c_clk: Maximum I2C clock speed
181 * @bus_hold_flag: Flag used in repeated start for clearing HOLD bit
182 * @clk: Pointer to struct clk
183 * @clk_rate_change_nb: Notifier block for clock rate changes
184 * @quirks: flag for broken hold bit usage in r1p10
185 * @ctrl_reg: Cached value of the control register.
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 */
191 struct cdns_i2c {
192 struct device *dev;
193 void __iomem *membase;
194 struct i2c_adapter adap;
195 struct i2c_msg *p_msg;
196 int err_status;
197 struct completion xfer_done;
198 unsigned char *p_send_buf;
199 unsigned char *p_recv_buf;
200 unsigned int send_count;
201 unsigned int recv_count;
202 unsigned int curr_recv_count;
203 int irq;
204 unsigned long input_clk;
205 unsigned int i2c_clk;
206 unsigned int bus_hold_flag;
207 struct clk *clk;
208 struct notifier_block clk_rate_change_nb;
209 u32 quirks;
210 u32 ctrl_reg;
211 struct i2c_bus_recovery_info rinfo;
212 #if IS_ENABLED(CONFIG_I2C_SLAVE)
213 u16 ctrl_reg_diva_divb;
214 struct i2c_client *slave;
215 enum cdns_i2c_mode dev_mode;
216 enum cdns_i2c_slave_state slave_state;
217 #endif
218 };
219
220 struct cdns_platform_data {
221 u32 quirks;
222 };
223
224 #define to_cdns_i2c(_nb) container_of(_nb, struct cdns_i2c, \
225 clk_rate_change_nb)
226
227 /**
228 * cdns_i2c_clear_bus_hold - Clear bus hold bit
229 * @id: Pointer to driver data struct
230 *
231 * Helper to clear the controller's bus hold bit.
232 */
cdns_i2c_clear_bus_hold(struct cdns_i2c * id)233 static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id)
234 {
235 u32 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
236 if (reg & CDNS_I2C_CR_HOLD)
237 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_HOLD, CDNS_I2C_CR_OFFSET);
238 }
239
cdns_is_holdquirk(struct cdns_i2c * id,bool hold_wrkaround)240 static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround)
241 {
242 return (hold_wrkaround &&
243 (id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1));
244 }
245
246 #if IS_ENABLED(CONFIG_I2C_SLAVE)
cdns_i2c_set_mode(enum cdns_i2c_mode mode,struct cdns_i2c * id)247 static void cdns_i2c_set_mode(enum cdns_i2c_mode mode, struct cdns_i2c *id)
248 {
249 /* Disable all interrupts */
250 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET);
251
252 /* Clear FIFO and transfer size */
253 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET);
254
255 /* Update device mode and state */
256 id->dev_mode = mode;
257 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
258
259 switch (mode) {
260 case CDNS_I2C_MODE_MASTER:
261 /* Enable i2c master */
262 cdns_i2c_writereg(id->ctrl_reg_diva_divb |
263 CDNS_I2C_CR_MASTER_EN_MASK,
264 CDNS_I2C_CR_OFFSET);
265 /*
266 * This delay is needed to give the IP some time to switch to
267 * the master mode. With lower values(like 110 us) i2cdetect
268 * will not detect any slave and without this delay, the IP will
269 * trigger a timeout interrupt.
270 */
271 usleep_range(115, 125);
272 break;
273 case CDNS_I2C_MODE_SLAVE:
274 /* Enable i2c slave */
275 cdns_i2c_writereg(id->ctrl_reg_diva_divb &
276 CDNS_I2C_CR_SLAVE_EN_MASK,
277 CDNS_I2C_CR_OFFSET);
278
279 /* Setting slave address */
280 cdns_i2c_writereg(id->slave->addr & CDNS_I2C_ADDR_MASK,
281 CDNS_I2C_ADDR_OFFSET);
282
283 /* Enable slave send/receive interrupts */
284 cdns_i2c_writereg(CDNS_I2C_IXR_SLAVE_INTR_MASK,
285 CDNS_I2C_IER_OFFSET);
286 break;
287 }
288 }
289
cdns_i2c_slave_rcv_data(struct cdns_i2c * id)290 static void cdns_i2c_slave_rcv_data(struct cdns_i2c *id)
291 {
292 u8 bytes;
293 unsigned char data;
294
295 /* Prepare backend for data reception */
296 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) {
297 id->slave_state = CDNS_I2C_SLAVE_STATE_RECV;
298 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_REQUESTED, NULL);
299 }
300
301 /* Fetch number of bytes to receive */
302 bytes = cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
303
304 /* Read data and send to backend */
305 while (bytes--) {
306 data = cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
307 i2c_slave_event(id->slave, I2C_SLAVE_WRITE_RECEIVED, &data);
308 }
309 }
310
cdns_i2c_slave_send_data(struct cdns_i2c * id)311 static void cdns_i2c_slave_send_data(struct cdns_i2c *id)
312 {
313 u8 data;
314
315 /* Prepare backend for data transmission */
316 if (id->slave_state == CDNS_I2C_SLAVE_STATE_IDLE) {
317 id->slave_state = CDNS_I2C_SLAVE_STATE_SEND;
318 i2c_slave_event(id->slave, I2C_SLAVE_READ_REQUESTED, &data);
319 } else {
320 i2c_slave_event(id->slave, I2C_SLAVE_READ_PROCESSED, &data);
321 }
322
323 /* Send data over bus */
324 cdns_i2c_writereg(data, CDNS_I2C_DATA_OFFSET);
325 }
326
327 /**
328 * cdns_i2c_slave_isr - Interrupt handler for the I2C device in slave role
329 * @ptr: Pointer to I2C device private data
330 *
331 * This function handles the data interrupt and transfer complete interrupt of
332 * the I2C device in slave role.
333 *
334 * Return: IRQ_HANDLED always
335 */
cdns_i2c_slave_isr(void * ptr)336 static irqreturn_t cdns_i2c_slave_isr(void *ptr)
337 {
338 struct cdns_i2c *id = ptr;
339 unsigned int isr_status, i2c_status;
340
341 /* Fetch the interrupt status */
342 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
343 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
344
345 /* Ignore masked interrupts */
346 isr_status &= ~cdns_i2c_readreg(CDNS_I2C_IMR_OFFSET);
347
348 /* Fetch transfer mode (send/receive) */
349 i2c_status = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET);
350
351 /* Handle data send/receive */
352 if (i2c_status & CDNS_I2C_SR_RXRW) {
353 /* Send data to master */
354 if (isr_status & CDNS_I2C_IXR_DATA)
355 cdns_i2c_slave_send_data(id);
356
357 if (isr_status & CDNS_I2C_IXR_COMP) {
358 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
359 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL);
360 }
361 } else {
362 /* Receive data from master */
363 if (isr_status & CDNS_I2C_IXR_DATA)
364 cdns_i2c_slave_rcv_data(id);
365
366 if (isr_status & CDNS_I2C_IXR_COMP) {
367 cdns_i2c_slave_rcv_data(id);
368 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
369 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL);
370 }
371 }
372
373 /* Master indicated xfer stop or fifo underflow/overflow */
374 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_RX_OVF |
375 CDNS_I2C_IXR_RX_UNF | CDNS_I2C_IXR_TX_OVF)) {
376 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
377 i2c_slave_event(id->slave, I2C_SLAVE_STOP, NULL);
378 cdns_i2c_writereg(CDNS_I2C_CR_CLR_FIFO, CDNS_I2C_CR_OFFSET);
379 }
380
381 return IRQ_HANDLED;
382 }
383 #endif
384
385 /**
386 * cdns_i2c_master_isr - Interrupt handler for the I2C device in master role
387 * @ptr: Pointer to I2C device private data
388 *
389 * This function handles the data interrupt, transfer complete interrupt and
390 * the error interrupts of the I2C device in master role.
391 *
392 * Return: IRQ_HANDLED always
393 */
cdns_i2c_master_isr(void * ptr)394 static irqreturn_t cdns_i2c_master_isr(void *ptr)
395 {
396 unsigned int isr_status, avail_bytes;
397 unsigned int bytes_to_send;
398 bool updatetx;
399 struct cdns_i2c *id = ptr;
400 /* Signal completion only after everything is updated */
401 int done_flag = 0;
402 irqreturn_t status = IRQ_NONE;
403
404 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
405 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
406 id->err_status = 0;
407
408 /* Handling nack and arbitration lost interrupt */
409 if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) {
410 done_flag = 1;
411 status = IRQ_HANDLED;
412 }
413
414 /*
415 * Check if transfer size register needs to be updated again for a
416 * large data receive operation.
417 */
418 updatetx = id->recv_count > id->curr_recv_count;
419
420 /* When receiving, handle data interrupt and completion interrupt */
421 if (id->p_recv_buf &&
422 ((isr_status & CDNS_I2C_IXR_COMP) ||
423 (isr_status & CDNS_I2C_IXR_DATA))) {
424 /* Read data if receive data valid is set */
425 while (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) &
426 CDNS_I2C_SR_RXDV) {
427 if (id->recv_count > 0) {
428 *(id->p_recv_buf)++ =
429 cdns_i2c_readreg(CDNS_I2C_DATA_OFFSET);
430 id->recv_count--;
431 id->curr_recv_count--;
432
433 /*
434 * Clear hold bit that was set for FIFO control
435 * if RX data left is less than or equal to
436 * FIFO DEPTH unless repeated start is selected
437 */
438 if (id->recv_count <= CDNS_I2C_FIFO_DEPTH &&
439 !id->bus_hold_flag)
440 cdns_i2c_clear_bus_hold(id);
441
442 } else {
443 dev_err(id->adap.dev.parent,
444 "xfer_size reg rollover. xfer aborted!\n");
445 id->err_status |= CDNS_I2C_IXR_TO;
446 break;
447 }
448
449 if (cdns_is_holdquirk(id, updatetx))
450 break;
451 }
452
453 /*
454 * The controller sends NACK to the slave when transfer size
455 * register reaches zero without considering the HOLD bit.
456 * This workaround is implemented for large data transfers to
457 * maintain transfer size non-zero while performing a large
458 * receive operation.
459 */
460 if (cdns_is_holdquirk(id, updatetx)) {
461 /* wait while fifo is full */
462 while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) !=
463 (id->curr_recv_count - CDNS_I2C_FIFO_DEPTH))
464 ;
465
466 /*
467 * Check number of bytes to be received against maximum
468 * transfer size and update register accordingly.
469 */
470 if (((int)(id->recv_count) - CDNS_I2C_FIFO_DEPTH) >
471 CDNS_I2C_TRANSFER_SIZE) {
472 cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE,
473 CDNS_I2C_XFER_SIZE_OFFSET);
474 id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE +
475 CDNS_I2C_FIFO_DEPTH;
476 } else {
477 cdns_i2c_writereg(id->recv_count -
478 CDNS_I2C_FIFO_DEPTH,
479 CDNS_I2C_XFER_SIZE_OFFSET);
480 id->curr_recv_count = id->recv_count;
481 }
482 }
483
484 /* Clear hold (if not repeated start) and signal completion */
485 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->recv_count) {
486 if (!id->bus_hold_flag)
487 cdns_i2c_clear_bus_hold(id);
488 done_flag = 1;
489 }
490
491 status = IRQ_HANDLED;
492 }
493
494 /* When sending, handle transfer complete interrupt */
495 if ((isr_status & CDNS_I2C_IXR_COMP) && !id->p_recv_buf) {
496 /*
497 * If there is more data to be sent, calculate the
498 * space available in FIFO and fill with that many bytes.
499 */
500 if (id->send_count) {
501 avail_bytes = CDNS_I2C_FIFO_DEPTH -
502 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
503 if (id->send_count > avail_bytes)
504 bytes_to_send = avail_bytes;
505 else
506 bytes_to_send = id->send_count;
507
508 while (bytes_to_send--) {
509 cdns_i2c_writereg(
510 (*(id->p_send_buf)++),
511 CDNS_I2C_DATA_OFFSET);
512 id->send_count--;
513 }
514 } else {
515 /*
516 * Signal the completion of transaction and
517 * clear the hold bus bit if there are no
518 * further messages to be processed.
519 */
520 done_flag = 1;
521 }
522 if (!id->send_count && !id->bus_hold_flag)
523 cdns_i2c_clear_bus_hold(id);
524
525 status = IRQ_HANDLED;
526 }
527
528 /* Update the status for errors */
529 id->err_status |= isr_status & CDNS_I2C_IXR_ERR_INTR_MASK;
530 if (id->err_status)
531 status = IRQ_HANDLED;
532
533 if (done_flag)
534 complete(&id->xfer_done);
535
536 return status;
537 }
538
539 /**
540 * cdns_i2c_isr - Interrupt handler for the I2C device
541 * @irq: irq number for the I2C device
542 * @ptr: void pointer to cdns_i2c structure
543 *
544 * This function passes the control to slave/master based on current role of
545 * i2c controller.
546 *
547 * Return: IRQ_HANDLED always
548 */
cdns_i2c_isr(int irq,void * ptr)549 static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
550 {
551 #if IS_ENABLED(CONFIG_I2C_SLAVE)
552 struct cdns_i2c *id = ptr;
553
554 if (id->dev_mode == CDNS_I2C_MODE_SLAVE)
555 return cdns_i2c_slave_isr(ptr);
556 #endif
557 return cdns_i2c_master_isr(ptr);
558 }
559
560 /**
561 * cdns_i2c_mrecv - Prepare and start a master receive operation
562 * @id: pointer to the i2c device structure
563 */
cdns_i2c_mrecv(struct cdns_i2c * id)564 static void cdns_i2c_mrecv(struct cdns_i2c *id)
565 {
566 unsigned int ctrl_reg;
567 unsigned int isr_status;
568 unsigned long flags;
569 bool hold_clear = false;
570 bool irq_save = false;
571
572 u32 addr;
573
574 id->p_recv_buf = id->p_msg->buf;
575 id->recv_count = id->p_msg->len;
576
577 /* Put the controller in master receive mode and clear the FIFO */
578 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
579 ctrl_reg |= CDNS_I2C_CR_RW | CDNS_I2C_CR_CLR_FIFO;
580
581 /*
582 * Receive up to I2C_SMBUS_BLOCK_MAX data bytes, plus one message length
583 * byte, plus one checksum byte if PEC is enabled. p_msg->len will be 2 if
584 * PEC is enabled, otherwise 1.
585 */
586 if (id->p_msg->flags & I2C_M_RECV_LEN)
587 id->recv_count = I2C_SMBUS_BLOCK_MAX + id->p_msg->len;
588
589 id->curr_recv_count = id->recv_count;
590
591 /*
592 * Check for the message size against FIFO depth and set the
593 * 'hold bus' bit if it is greater than FIFO depth.
594 */
595 if (id->recv_count > CDNS_I2C_FIFO_DEPTH)
596 ctrl_reg |= CDNS_I2C_CR_HOLD;
597
598 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
599
600 /* Clear the interrupts in interrupt status register */
601 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
602 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
603
604 /*
605 * The no. of bytes to receive is checked against the limit of
606 * max transfer size. Set transfer size register with no of bytes
607 * receive if it is less than transfer size and transfer size if
608 * it is more. Enable the interrupts.
609 */
610 if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) {
611 cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE,
612 CDNS_I2C_XFER_SIZE_OFFSET);
613 id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
614 } else {
615 cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET);
616 }
617
618 /* Determine hold_clear based on number of bytes to receive and hold flag */
619 if (!id->bus_hold_flag &&
620 ((id->p_msg->flags & I2C_M_RECV_LEN) != I2C_M_RECV_LEN) &&
621 (id->recv_count <= CDNS_I2C_FIFO_DEPTH)) {
622 if (cdns_i2c_readreg(CDNS_I2C_CR_OFFSET) & CDNS_I2C_CR_HOLD) {
623 hold_clear = true;
624 if (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT)
625 irq_save = true;
626 }
627 }
628
629 addr = id->p_msg->addr;
630 addr &= CDNS_I2C_ADDR_MASK;
631
632 if (hold_clear) {
633 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET) & ~CDNS_I2C_CR_HOLD;
634 /*
635 * In case of Xilinx Zynq SOC, clear the HOLD bit before transfer size
636 * register reaches '0'. This is an IP bug which causes transfer size
637 * register overflow to 0xFF. To satisfy this timing requirement,
638 * disable the interrupts on current processor core between register
639 * writes to slave address register and control register.
640 */
641 if (irq_save)
642 local_irq_save(flags);
643
644 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET);
645 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
646 /* Read it back to avoid bufferring and make sure write happens */
647 cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
648
649 if (irq_save)
650 local_irq_restore(flags);
651 } else {
652 cdns_i2c_writereg(addr, CDNS_I2C_ADDR_OFFSET);
653 }
654
655 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET);
656 }
657
658 /**
659 * cdns_i2c_msend - Prepare and start a master send operation
660 * @id: pointer to the i2c device
661 */
cdns_i2c_msend(struct cdns_i2c * id)662 static void cdns_i2c_msend(struct cdns_i2c *id)
663 {
664 unsigned int avail_bytes;
665 unsigned int bytes_to_send;
666 unsigned int ctrl_reg;
667 unsigned int isr_status;
668
669 id->p_recv_buf = NULL;
670 id->p_send_buf = id->p_msg->buf;
671 id->send_count = id->p_msg->len;
672
673 /* Set the controller in Master transmit mode and clear the FIFO. */
674 ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
675 ctrl_reg &= ~CDNS_I2C_CR_RW;
676 ctrl_reg |= CDNS_I2C_CR_CLR_FIFO;
677
678 /*
679 * Check for the message size against FIFO depth and set the
680 * 'hold bus' bit if it is greater than FIFO depth.
681 */
682 if (id->send_count > CDNS_I2C_FIFO_DEPTH)
683 ctrl_reg |= CDNS_I2C_CR_HOLD;
684 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
685
686 /* Clear the interrupts in interrupt status register. */
687 isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
688 cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
689
690 /*
691 * Calculate the space available in FIFO. Check the message length
692 * against the space available, and fill the FIFO accordingly.
693 * Enable the interrupts.
694 */
695 avail_bytes = CDNS_I2C_FIFO_DEPTH -
696 cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET);
697
698 if (id->send_count > avail_bytes)
699 bytes_to_send = avail_bytes;
700 else
701 bytes_to_send = id->send_count;
702
703 while (bytes_to_send--) {
704 cdns_i2c_writereg((*(id->p_send_buf)++), CDNS_I2C_DATA_OFFSET);
705 id->send_count--;
706 }
707
708 /*
709 * Clear the bus hold flag if there is no more data
710 * and if it is the last message.
711 */
712 if (!id->bus_hold_flag && !id->send_count)
713 cdns_i2c_clear_bus_hold(id);
714 /* Set the slave address in address register - triggers operation. */
715 cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK,
716 CDNS_I2C_ADDR_OFFSET);
717
718 cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET);
719 }
720
721 /**
722 * cdns_i2c_master_reset - Reset the interface
723 * @adap: pointer to the i2c adapter driver instance
724 *
725 * This function cleanup the fifos, clear the hold bit and status
726 * and disable the interrupts.
727 */
cdns_i2c_master_reset(struct i2c_adapter * adap)728 static void cdns_i2c_master_reset(struct i2c_adapter *adap)
729 {
730 struct cdns_i2c *id = adap->algo_data;
731 u32 regval;
732
733 /* Disable the interrupts */
734 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK, CDNS_I2C_IDR_OFFSET);
735 /* Clear the hold bit and fifos */
736 regval = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
737 regval &= ~CDNS_I2C_CR_HOLD;
738 regval |= CDNS_I2C_CR_CLR_FIFO;
739 cdns_i2c_writereg(regval, CDNS_I2C_CR_OFFSET);
740 /* Update the transfercount register to zero */
741 cdns_i2c_writereg(0, CDNS_I2C_XFER_SIZE_OFFSET);
742 /* Clear the interrupt status register */
743 regval = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
744 cdns_i2c_writereg(regval, CDNS_I2C_ISR_OFFSET);
745 /* Clear the status register */
746 regval = cdns_i2c_readreg(CDNS_I2C_SR_OFFSET);
747 cdns_i2c_writereg(regval, CDNS_I2C_SR_OFFSET);
748 }
749
cdns_i2c_process_msg(struct cdns_i2c * id,struct i2c_msg * msg,struct i2c_adapter * adap)750 static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg,
751 struct i2c_adapter *adap)
752 {
753 unsigned long time_left, msg_timeout;
754 u32 reg;
755
756 id->p_msg = msg;
757 id->err_status = 0;
758 reinit_completion(&id->xfer_done);
759
760 /* Check for the TEN Bit mode on each msg */
761 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
762 if (msg->flags & I2C_M_TEN) {
763 if (reg & CDNS_I2C_CR_NEA)
764 cdns_i2c_writereg(reg & ~CDNS_I2C_CR_NEA,
765 CDNS_I2C_CR_OFFSET);
766 } else {
767 if (!(reg & CDNS_I2C_CR_NEA))
768 cdns_i2c_writereg(reg | CDNS_I2C_CR_NEA,
769 CDNS_I2C_CR_OFFSET);
770 }
771
772 /* Check for the R/W flag on each msg */
773 if (msg->flags & I2C_M_RD)
774 cdns_i2c_mrecv(id);
775 else
776 cdns_i2c_msend(id);
777
778 /* Minimal time to execute this message */
779 msg_timeout = msecs_to_jiffies((1000 * msg->len * BITS_PER_BYTE) / id->i2c_clk);
780 /* Plus some wiggle room */
781 msg_timeout += msecs_to_jiffies(500);
782
783 if (msg_timeout < adap->timeout)
784 msg_timeout = adap->timeout;
785
786 /* Wait for the signal of completion */
787 time_left = wait_for_completion_timeout(&id->xfer_done, msg_timeout);
788 if (time_left == 0) {
789 cdns_i2c_master_reset(adap);
790 dev_err(id->adap.dev.parent,
791 "timeout waiting on completion\n");
792 return -ETIMEDOUT;
793 }
794
795 cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK,
796 CDNS_I2C_IDR_OFFSET);
797
798 /* If it is bus arbitration error, try again */
799 if (id->err_status & CDNS_I2C_IXR_ARB_LOST)
800 return -EAGAIN;
801
802 if (msg->flags & I2C_M_RECV_LEN)
803 msg->len += min_t(unsigned int, msg->buf[0], I2C_SMBUS_BLOCK_MAX);
804
805 return 0;
806 }
807
808 /**
809 * cdns_i2c_master_xfer - The main i2c transfer function
810 * @adap: pointer to the i2c adapter driver instance
811 * @msgs: pointer to the i2c message structure
812 * @num: the number of messages to transfer
813 *
814 * Initiates the send/recv activity based on the transfer message received.
815 *
816 * Return: number of msgs processed on success, negative error otherwise
817 */
cdns_i2c_master_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)818 static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
819 int num)
820 {
821 int ret, count;
822 u32 reg;
823 struct cdns_i2c *id = adap->algo_data;
824 bool hold_quirk;
825 #if IS_ENABLED(CONFIG_I2C_SLAVE)
826 bool change_role = false;
827 #endif
828
829 ret = pm_runtime_resume_and_get(id->dev);
830 if (ret < 0)
831 return ret;
832
833 #if IS_ENABLED(CONFIG_I2C_SLAVE)
834 /* Check i2c operating mode and switch if possible */
835 if (id->dev_mode == CDNS_I2C_MODE_SLAVE) {
836 if (id->slave_state != CDNS_I2C_SLAVE_STATE_IDLE)
837 return -EAGAIN;
838
839 /* Set mode to master */
840 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id);
841
842 /* Mark flag to change role once xfer is completed */
843 change_role = true;
844 }
845 #endif
846
847 /* Check if the bus is free */
848
849 ret = readl_relaxed_poll_timeout(id->membase + CDNS_I2C_SR_OFFSET,
850 reg,
851 !(reg & CDNS_I2C_SR_BA),
852 CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US);
853 if (ret) {
854 ret = -EAGAIN;
855 if (id->adap.bus_recovery_info)
856 i2c_recover_bus(adap);
857 goto out;
858 }
859
860 hold_quirk = !!(id->quirks & CDNS_I2C_BROKEN_HOLD_BIT);
861 /*
862 * Set the flag to one when multiple messages are to be
863 * processed with a repeated start.
864 */
865 if (num > 1) {
866 /*
867 * This controller does not give completion interrupt after a
868 * master receive message if HOLD bit is set (repeated start),
869 * resulting in SW timeout. Hence, if a receive message is
870 * followed by any other message, an error is returned
871 * indicating that this sequence is not supported.
872 */
873 for (count = 0; (count < num - 1 && hold_quirk); count++) {
874 if (msgs[count].flags & I2C_M_RD) {
875 dev_warn(adap->dev.parent,
876 "Can't do repeated start after a receive message\n");
877 ret = -EOPNOTSUPP;
878 goto out;
879 }
880 }
881 id->bus_hold_flag = 1;
882 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
883 reg |= CDNS_I2C_CR_HOLD;
884 cdns_i2c_writereg(reg, CDNS_I2C_CR_OFFSET);
885 } else {
886 id->bus_hold_flag = 0;
887 }
888
889 /* Process the msg one by one */
890 for (count = 0; count < num; count++, msgs++) {
891 if (count == (num - 1))
892 id->bus_hold_flag = 0;
893
894 ret = cdns_i2c_process_msg(id, msgs, adap);
895 if (ret)
896 goto out;
897
898 /* Report the other error interrupts to application */
899 if (id->err_status) {
900 cdns_i2c_master_reset(adap);
901
902 if (id->err_status & CDNS_I2C_IXR_NACK) {
903 ret = -ENXIO;
904 goto out;
905 }
906 ret = -EIO;
907 goto out;
908 }
909 }
910
911 ret = num;
912
913 out:
914
915 #if IS_ENABLED(CONFIG_I2C_SLAVE)
916 /* Switch i2c mode to slave */
917 if (change_role)
918 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id);
919 #endif
920
921 pm_runtime_mark_last_busy(id->dev);
922 pm_runtime_put_autosuspend(id->dev);
923 return ret;
924 }
925
926 /**
927 * cdns_i2c_func - Returns the supported features of the I2C driver
928 * @adap: pointer to the i2c adapter structure
929 *
930 * Return: 32 bit value, each bit corresponding to a feature
931 */
cdns_i2c_func(struct i2c_adapter * adap)932 static u32 cdns_i2c_func(struct i2c_adapter *adap)
933 {
934 u32 func = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
935 (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
936 I2C_FUNC_SMBUS_BLOCK_DATA;
937
938 #if IS_ENABLED(CONFIG_I2C_SLAVE)
939 func |= I2C_FUNC_SLAVE;
940 #endif
941
942 return func;
943 }
944
945 #if IS_ENABLED(CONFIG_I2C_SLAVE)
cdns_reg_slave(struct i2c_client * slave)946 static int cdns_reg_slave(struct i2c_client *slave)
947 {
948 int ret;
949 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c,
950 adap);
951
952 if (id->slave)
953 return -EBUSY;
954
955 if (slave->flags & I2C_CLIENT_TEN)
956 return -EAFNOSUPPORT;
957
958 ret = pm_runtime_resume_and_get(id->dev);
959 if (ret < 0)
960 return ret;
961
962 /* Store slave information */
963 id->slave = slave;
964
965 /* Enable I2C slave */
966 cdns_i2c_set_mode(CDNS_I2C_MODE_SLAVE, id);
967
968 return 0;
969 }
970
cdns_unreg_slave(struct i2c_client * slave)971 static int cdns_unreg_slave(struct i2c_client *slave)
972 {
973 struct cdns_i2c *id = container_of(slave->adapter, struct cdns_i2c,
974 adap);
975
976 pm_runtime_put(id->dev);
977
978 /* Remove slave information */
979 id->slave = NULL;
980
981 /* Enable I2C master */
982 cdns_i2c_set_mode(CDNS_I2C_MODE_MASTER, id);
983
984 return 0;
985 }
986 #endif
987
988 static const struct i2c_algorithm cdns_i2c_algo = {
989 .master_xfer = cdns_i2c_master_xfer,
990 .functionality = cdns_i2c_func,
991 #if IS_ENABLED(CONFIG_I2C_SLAVE)
992 .reg_slave = cdns_reg_slave,
993 .unreg_slave = cdns_unreg_slave,
994 #endif
995 };
996
997 /**
998 * cdns_i2c_calc_divs - Calculate clock dividers
999 * @f: I2C clock frequency
1000 * @input_clk: Input clock frequency
1001 * @a: First divider (return value)
1002 * @b: Second divider (return value)
1003 *
1004 * f is used as input and output variable. As input it is used as target I2C
1005 * frequency. On function exit f holds the actually resulting I2C frequency.
1006 *
1007 * Return: 0 on success, negative errno otherwise.
1008 */
cdns_i2c_calc_divs(unsigned long * f,unsigned long input_clk,unsigned int * a,unsigned int * b)1009 static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk,
1010 unsigned int *a, unsigned int *b)
1011 {
1012 unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp;
1013 unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0;
1014 unsigned int last_error, current_error;
1015
1016 /* calculate (divisor_a+1) x (divisor_b+1) */
1017 temp = input_clk / (22 * fscl);
1018
1019 /*
1020 * If the calculated value is negative or 0, the fscl input is out of
1021 * range. Return error.
1022 */
1023 if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX)))
1024 return -EINVAL;
1025
1026 last_error = -1;
1027 for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) {
1028 div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1));
1029
1030 if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX))
1031 continue;
1032 div_b--;
1033
1034 actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1));
1035
1036 if (actual_fscl > fscl)
1037 continue;
1038
1039 current_error = ((actual_fscl > fscl) ? (actual_fscl - fscl) :
1040 (fscl - actual_fscl));
1041
1042 if (last_error > current_error) {
1043 calc_div_a = div_a;
1044 calc_div_b = div_b;
1045 best_fscl = actual_fscl;
1046 last_error = current_error;
1047 }
1048 }
1049
1050 *a = calc_div_a;
1051 *b = calc_div_b;
1052 *f = best_fscl;
1053
1054 return 0;
1055 }
1056
1057 /**
1058 * cdns_i2c_setclk - This function sets the serial clock rate for the I2C device
1059 * @clk_in: I2C clock input frequency in Hz
1060 * @id: Pointer to the I2C device structure
1061 *
1062 * The device must be idle rather than busy transferring data before setting
1063 * these device options.
1064 * The data rate is set by values in the control register.
1065 * The formula for determining the correct register values is
1066 * Fscl = Fpclk/(22 x (divisor_a+1) x (divisor_b+1))
1067 * See the hardware data sheet for a full explanation of setting the serial
1068 * clock rate. The clock can not be faster than the input clock divide by 22.
1069 * The two most common clock rates are 100KHz and 400KHz.
1070 *
1071 * Return: 0 on success, negative error otherwise
1072 */
cdns_i2c_setclk(unsigned long clk_in,struct cdns_i2c * id)1073 static int cdns_i2c_setclk(unsigned long clk_in, struct cdns_i2c *id)
1074 {
1075 unsigned int div_a, div_b;
1076 unsigned int ctrl_reg;
1077 int ret = 0;
1078 unsigned long fscl = id->i2c_clk;
1079
1080 ret = cdns_i2c_calc_divs(&fscl, clk_in, &div_a, &div_b);
1081 if (ret)
1082 return ret;
1083
1084 ctrl_reg = id->ctrl_reg;
1085 ctrl_reg &= ~(CDNS_I2C_CR_DIVA_MASK | CDNS_I2C_CR_DIVB_MASK);
1086 ctrl_reg |= ((div_a << CDNS_I2C_CR_DIVA_SHIFT) |
1087 (div_b << CDNS_I2C_CR_DIVB_SHIFT));
1088 id->ctrl_reg = ctrl_reg;
1089 cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
1090 #if IS_ENABLED(CONFIG_I2C_SLAVE)
1091 id->ctrl_reg_diva_divb = ctrl_reg & (CDNS_I2C_CR_DIVA_MASK |
1092 CDNS_I2C_CR_DIVB_MASK);
1093 #endif
1094 return 0;
1095 }
1096
1097 /**
1098 * cdns_i2c_clk_notifier_cb - Clock rate change callback
1099 * @nb: Pointer to notifier block
1100 * @event: Notification reason
1101 * @data: Pointer to notification data object
1102 *
1103 * This function is called when the cdns_i2c input clock frequency changes.
1104 * The callback checks whether a valid bus frequency can be generated after the
1105 * change. If so, the change is acknowledged, otherwise the change is aborted.
1106 * New dividers are written to the HW in the pre- or post change notification
1107 * depending on the scaling direction.
1108 *
1109 * Return: NOTIFY_STOP if the rate change should be aborted, NOTIFY_OK
1110 * to acknowledge the change, NOTIFY_DONE if the notification is
1111 * considered irrelevant.
1112 */
cdns_i2c_clk_notifier_cb(struct notifier_block * nb,unsigned long event,void * data)1113 static int cdns_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
1114 event, void *data)
1115 {
1116 struct clk_notifier_data *ndata = data;
1117 struct cdns_i2c *id = to_cdns_i2c(nb);
1118
1119 if (pm_runtime_suspended(id->dev))
1120 return NOTIFY_OK;
1121
1122 switch (event) {
1123 case PRE_RATE_CHANGE:
1124 {
1125 unsigned long input_clk = ndata->new_rate;
1126 unsigned long fscl = id->i2c_clk;
1127 unsigned int div_a, div_b;
1128 int ret;
1129
1130 ret = cdns_i2c_calc_divs(&fscl, input_clk, &div_a, &div_b);
1131 if (ret) {
1132 dev_warn(id->adap.dev.parent,
1133 "clock rate change rejected\n");
1134 return NOTIFY_STOP;
1135 }
1136
1137 /* scale up */
1138 if (ndata->new_rate > ndata->old_rate)
1139 cdns_i2c_setclk(ndata->new_rate, id);
1140
1141 return NOTIFY_OK;
1142 }
1143 case POST_RATE_CHANGE:
1144 id->input_clk = ndata->new_rate;
1145 /* scale down */
1146 if (ndata->new_rate < ndata->old_rate)
1147 cdns_i2c_setclk(ndata->new_rate, id);
1148 return NOTIFY_OK;
1149 case ABORT_RATE_CHANGE:
1150 /* scale up */
1151 if (ndata->new_rate > ndata->old_rate)
1152 cdns_i2c_setclk(ndata->old_rate, id);
1153 return NOTIFY_OK;
1154 default:
1155 return NOTIFY_DONE;
1156 }
1157 }
1158
1159 /**
1160 * cdns_i2c_runtime_suspend - Runtime suspend method for the driver
1161 * @dev: Address of the platform_device structure
1162 *
1163 * Put the driver into low power mode.
1164 *
1165 * Return: 0 always
1166 */
cdns_i2c_runtime_suspend(struct device * dev)1167 static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev)
1168 {
1169 struct cdns_i2c *xi2c = dev_get_drvdata(dev);
1170
1171 clk_disable(xi2c->clk);
1172
1173 return 0;
1174 }
1175
1176 /**
1177 * cdns_i2c_init - Controller initialisation
1178 * @id: Device private data structure
1179 *
1180 * Initialise the i2c controller.
1181 *
1182 */
cdns_i2c_init(struct cdns_i2c * id)1183 static void cdns_i2c_init(struct cdns_i2c *id)
1184 {
1185 cdns_i2c_writereg(id->ctrl_reg, CDNS_I2C_CR_OFFSET);
1186 /*
1187 * Cadence I2C controller has a bug wherein it generates
1188 * invalid read transaction after HW timeout in master receiver mode.
1189 * HW timeout is not used by this driver and the interrupt is disabled.
1190 * But the feature itself cannot be disabled. Hence maximum value
1191 * is written to this register to reduce the chances of error.
1192 */
1193 cdns_i2c_writereg(CDNS_I2C_TIMEOUT_MAX, CDNS_I2C_TIME_OUT_OFFSET);
1194 }
1195
1196 /**
1197 * cdns_i2c_runtime_resume - Runtime resume
1198 * @dev: Address of the platform_device structure
1199 *
1200 * Runtime resume callback.
1201 *
1202 * Return: 0 on success and error value on error
1203 */
cdns_i2c_runtime_resume(struct device * dev)1204 static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev)
1205 {
1206 struct cdns_i2c *xi2c = dev_get_drvdata(dev);
1207 int ret;
1208
1209 ret = clk_enable(xi2c->clk);
1210 if (ret) {
1211 dev_err(dev, "Cannot enable clock.\n");
1212 return ret;
1213 }
1214 cdns_i2c_init(xi2c);
1215
1216 return 0;
1217 }
1218
1219 static const struct dev_pm_ops cdns_i2c_dev_pm_ops = {
1220 SET_RUNTIME_PM_OPS(cdns_i2c_runtime_suspend,
1221 cdns_i2c_runtime_resume, NULL)
1222 };
1223
1224 static const struct cdns_platform_data r1p10_i2c_def = {
1225 .quirks = CDNS_I2C_BROKEN_HOLD_BIT,
1226 };
1227
1228 static const struct of_device_id cdns_i2c_of_match[] = {
1229 { .compatible = "cdns,i2c-r1p10", .data = &r1p10_i2c_def },
1230 { .compatible = "cdns,i2c-r1p14",},
1231 { /* end of table */ }
1232 };
1233 MODULE_DEVICE_TABLE(of, cdns_i2c_of_match);
1234
1235 /**
1236 * cdns_i2c_probe - Platform registration call
1237 * @pdev: Handle to the platform device structure
1238 *
1239 * This function does all the memory allocation and registration for the i2c
1240 * device. User can modify the address mode to 10 bit address mode using the
1241 * ioctl call with option I2C_TENBIT.
1242 *
1243 * Return: 0 on success, negative error otherwise
1244 */
cdns_i2c_probe(struct platform_device * pdev)1245 static int cdns_i2c_probe(struct platform_device *pdev)
1246 {
1247 struct resource *r_mem;
1248 struct cdns_i2c *id;
1249 int ret;
1250 const struct of_device_id *match;
1251
1252 id = devm_kzalloc(&pdev->dev, sizeof(*id), GFP_KERNEL);
1253 if (!id)
1254 return -ENOMEM;
1255
1256 id->dev = &pdev->dev;
1257 platform_set_drvdata(pdev, id);
1258
1259 match = of_match_node(cdns_i2c_of_match, pdev->dev.of_node);
1260 if (match && match->data) {
1261 const struct cdns_platform_data *data = match->data;
1262 id->quirks = data->quirks;
1263 }
1264
1265 id->rinfo.pinctrl = devm_pinctrl_get(&pdev->dev);
1266 if (IS_ERR(id->rinfo.pinctrl)) {
1267 int err = PTR_ERR(id->rinfo.pinctrl);
1268
1269 dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
1270 if (err != -ENODEV)
1271 return err;
1272 } else {
1273 id->adap.bus_recovery_info = &id->rinfo;
1274 }
1275
1276 id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem);
1277 if (IS_ERR(id->membase))
1278 return PTR_ERR(id->membase);
1279
1280 ret = platform_get_irq(pdev, 0);
1281 if (ret < 0)
1282 return ret;
1283 id->irq = ret;
1284
1285 id->adap.owner = THIS_MODULE;
1286 id->adap.dev.of_node = pdev->dev.of_node;
1287 id->adap.algo = &cdns_i2c_algo;
1288 id->adap.timeout = CDNS_I2C_TIMEOUT;
1289 id->adap.retries = 3; /* Default retry value. */
1290 id->adap.algo_data = id;
1291 id->adap.dev.parent = &pdev->dev;
1292 init_completion(&id->xfer_done);
1293 snprintf(id->adap.name, sizeof(id->adap.name),
1294 "Cadence I2C at %08lx", (unsigned long)r_mem->start);
1295
1296 id->clk = devm_clk_get(&pdev->dev, NULL);
1297 if (IS_ERR(id->clk))
1298 return dev_err_probe(&pdev->dev, PTR_ERR(id->clk),
1299 "input clock not found.\n");
1300
1301 ret = clk_prepare_enable(id->clk);
1302 if (ret)
1303 dev_err(&pdev->dev, "Unable to enable clock.\n");
1304
1305 pm_runtime_set_autosuspend_delay(id->dev, CNDS_I2C_PM_TIMEOUT);
1306 pm_runtime_use_autosuspend(id->dev);
1307 pm_runtime_set_active(id->dev);
1308 pm_runtime_enable(id->dev);
1309
1310 id->clk_rate_change_nb.notifier_call = cdns_i2c_clk_notifier_cb;
1311 if (clk_notifier_register(id->clk, &id->clk_rate_change_nb))
1312 dev_warn(&pdev->dev, "Unable to register clock notifier.\n");
1313 id->input_clk = clk_get_rate(id->clk);
1314
1315 ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
1316 &id->i2c_clk);
1317 if (ret || (id->i2c_clk > I2C_MAX_FAST_MODE_FREQ))
1318 id->i2c_clk = I2C_MAX_STANDARD_MODE_FREQ;
1319
1320 #if IS_ENABLED(CONFIG_I2C_SLAVE)
1321 /* Set initial mode to master */
1322 id->dev_mode = CDNS_I2C_MODE_MASTER;
1323 id->slave_state = CDNS_I2C_SLAVE_STATE_IDLE;
1324 #endif
1325 id->ctrl_reg = CDNS_I2C_CR_ACK_EN | CDNS_I2C_CR_NEA | CDNS_I2C_CR_MS;
1326
1327 ret = cdns_i2c_setclk(id->input_clk, id);
1328 if (ret) {
1329 dev_err(&pdev->dev, "invalid SCL clock: %u Hz\n", id->i2c_clk);
1330 ret = -EINVAL;
1331 goto err_clk_dis;
1332 }
1333
1334 ret = devm_request_irq(&pdev->dev, id->irq, cdns_i2c_isr, 0,
1335 DRIVER_NAME, id);
1336 if (ret) {
1337 dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
1338 goto err_clk_dis;
1339 }
1340 cdns_i2c_init(id);
1341
1342 ret = i2c_add_adapter(&id->adap);
1343 if (ret < 0)
1344 goto err_clk_dis;
1345
1346 dev_info(&pdev->dev, "%u kHz mmio %08lx irq %d\n",
1347 id->i2c_clk / 1000, (unsigned long)r_mem->start, id->irq);
1348
1349 return 0;
1350
1351 err_clk_dis:
1352 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
1353 clk_disable_unprepare(id->clk);
1354 pm_runtime_disable(&pdev->dev);
1355 pm_runtime_set_suspended(&pdev->dev);
1356 return ret;
1357 }
1358
1359 /**
1360 * cdns_i2c_remove - Unregister the device after releasing the resources
1361 * @pdev: Handle to the platform device structure
1362 *
1363 * This function frees all the resources allocated to the device.
1364 *
1365 * Return: 0 always
1366 */
cdns_i2c_remove(struct platform_device * pdev)1367 static int cdns_i2c_remove(struct platform_device *pdev)
1368 {
1369 struct cdns_i2c *id = platform_get_drvdata(pdev);
1370
1371 pm_runtime_disable(&pdev->dev);
1372 pm_runtime_set_suspended(&pdev->dev);
1373 pm_runtime_dont_use_autosuspend(&pdev->dev);
1374
1375 i2c_del_adapter(&id->adap);
1376 clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
1377 clk_disable_unprepare(id->clk);
1378
1379 return 0;
1380 }
1381
1382 static struct platform_driver cdns_i2c_drv = {
1383 .driver = {
1384 .name = DRIVER_NAME,
1385 .of_match_table = cdns_i2c_of_match,
1386 .pm = &cdns_i2c_dev_pm_ops,
1387 },
1388 .probe = cdns_i2c_probe,
1389 .remove = cdns_i2c_remove,
1390 };
1391
1392 module_platform_driver(cdns_i2c_drv);
1393
1394 MODULE_AUTHOR("Xilinx Inc.");
1395 MODULE_DESCRIPTION("Cadence I2C bus driver");
1396 MODULE_LICENSE("GPL");
1397
