1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (C) 2015 Moritz Fischer <moritz.fischer@ettus.com>
4 * IP from Cadence (ID T-CS-PE-0007-100, Version R1p10f2)
6 * This file is based on: drivers/i2c/zynq_i2c.c,
7 * with added driver-model support and code cleanup.
13 #include <linux/bitops.h>
14 #include <linux/delay.h>
15 #include <linux/types.h>
17 #include <linux/errno.h>
18 #include <dm/device_compat.h>
26 /* i2c register set */
27 struct cdns_i2c_regs {
38 u32 interrupt_disable;
41 /* Control register fields */
42 #define CDNS_I2C_CONTROL_RW 0x00000001
43 #define CDNS_I2C_CONTROL_MS 0x00000002
44 #define CDNS_I2C_CONTROL_NEA 0x00000004
45 #define CDNS_I2C_CONTROL_ACKEN 0x00000008
46 #define CDNS_I2C_CONTROL_HOLD 0x00000010
47 #define CDNS_I2C_CONTROL_SLVMON 0x00000020
48 #define CDNS_I2C_CONTROL_CLR_FIFO 0x00000040
49 #define CDNS_I2C_CONTROL_DIV_B_SHIFT 8
50 #define CDNS_I2C_CONTROL_DIV_B_MASK 0x00003F00
51 #define CDNS_I2C_CONTROL_DIV_A_SHIFT 14
52 #define CDNS_I2C_CONTROL_DIV_A_MASK 0x0000C000
54 /* Status register values */
55 #define CDNS_I2C_STATUS_RXDV 0x00000020
56 #define CDNS_I2C_STATUS_TXDV 0x00000040
57 #define CDNS_I2C_STATUS_RXOVF 0x00000080
58 #define CDNS_I2C_STATUS_BA 0x00000100
60 /* Interrupt register fields */
61 #define CDNS_I2C_INTERRUPT_COMP 0x00000001
62 #define CDNS_I2C_INTERRUPT_DATA 0x00000002
63 #define CDNS_I2C_INTERRUPT_NACK 0x00000004
64 #define CDNS_I2C_INTERRUPT_TO 0x00000008
65 #define CDNS_I2C_INTERRUPT_SLVRDY 0x00000010
66 #define CDNS_I2C_INTERRUPT_RXOVF 0x00000020
67 #define CDNS_I2C_INTERRUPT_TXOVF 0x00000040
68 #define CDNS_I2C_INTERRUPT_RXUNF 0x00000080
69 #define CDNS_I2C_INTERRUPT_ARBLOST 0x00000200
71 #define CDNS_I2C_INTERRUPTS_MASK (CDNS_I2C_INTERRUPT_COMP | \
72 CDNS_I2C_INTERRUPT_DATA | \
73 CDNS_I2C_INTERRUPT_NACK | \
74 CDNS_I2C_INTERRUPT_TO | \
75 CDNS_I2C_INTERRUPT_SLVRDY | \
76 CDNS_I2C_INTERRUPT_RXOVF | \
77 CDNS_I2C_INTERRUPT_TXOVF | \
78 CDNS_I2C_INTERRUPT_RXUNF | \
79 CDNS_I2C_INTERRUPT_ARBLOST)
81 #define CDNS_I2C_FIFO_DEPTH 16
82 #define CDNS_I2C_TRANSFER_SIZE_MAX 255 /* Controller transfer limit */
83 #define CDNS_I2C_TRANSFER_SIZE (CDNS_I2C_TRANSFER_SIZE_MAX - 3)
85 #define CDNS_I2C_BROKEN_HOLD_BIT BIT(0)
87 #define CDNS_I2C_ARB_LOST_MAX_RETRIES 10
90 static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c)
94 int_status = readl(&cdns_i2c->interrupt_status);
96 status = readl(&cdns_i2c->status);
97 if (int_status || status) {
99 if (int_status & CDNS_I2C_INTERRUPT_COMP)
101 if (int_status & CDNS_I2C_INTERRUPT_DATA)
103 if (int_status & CDNS_I2C_INTERRUPT_NACK)
105 if (int_status & CDNS_I2C_INTERRUPT_TO)
107 if (int_status & CDNS_I2C_INTERRUPT_SLVRDY)
109 if (int_status & CDNS_I2C_INTERRUPT_RXOVF)
111 if (int_status & CDNS_I2C_INTERRUPT_TXOVF)
113 if (int_status & CDNS_I2C_INTERRUPT_RXUNF)
115 if (int_status & CDNS_I2C_INTERRUPT_ARBLOST)
117 if (status & CDNS_I2C_STATUS_RXDV)
119 if (status & CDNS_I2C_STATUS_TXDV)
121 if (status & CDNS_I2C_STATUS_RXOVF)
123 if (status & CDNS_I2C_STATUS_BA)
125 debug("TS%d ", readl(&cdns_i2c->transfer_size));
131 struct i2c_cdns_bus {
133 unsigned int input_freq;
134 struct cdns_i2c_regs __iomem *regs; /* register base */
140 struct cdns_i2c_platform_data {
144 /* Wait for an interrupt */
145 static u32 cdns_i2c_wait(struct cdns_i2c_regs *cdns_i2c, u32 mask)
147 int timeout, int_status;
149 for (timeout = 0; timeout < 100; timeout++) {
150 int_status = readl(&cdns_i2c->interrupt_status);
151 if (int_status & mask)
156 /* Clear interrupt status flags */
157 writel(int_status & mask, &cdns_i2c->interrupt_status);
159 return int_status & mask;
162 #define CDNS_I2C_DIVA_MAX 4
163 #define CDNS_I2C_DIVB_MAX 64
165 static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk,
166 unsigned int *a, unsigned int *b)
168 unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp;
169 unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0;
170 unsigned int last_error, current_error;
172 /* calculate (divisor_a+1) x (divisor_b+1) */
173 temp = input_clk / (22 * fscl);
176 * If the calculated value is negative or 0CDNS_I2C_DIVA_MAX,
177 * the fscl input is out of range. Return error.
179 if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX)))
183 for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) {
184 div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1));
186 if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX))
190 actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1));
192 if (actual_fscl > fscl)
195 current_error = ((actual_fscl > fscl) ? (actual_fscl - fscl) :
196 (fscl - actual_fscl));
198 if (last_error > current_error) {
201 best_fscl = actual_fscl;
202 last_error = current_error;
213 static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
215 struct i2c_cdns_bus *bus = dev_get_priv(dev);
216 u32 div_a = 0, div_b = 0;
217 unsigned long speed_p = speed;
220 if (speed > I2C_SPEED_FAST_RATE) {
221 debug("%s, failed to set clock speed to %u\n", __func__,
226 ret = cdns_i2c_calc_divs(&speed_p, bus->input_freq, &div_a, &div_b);
230 debug("%s: div_a: %d, div_b: %d, input freq: %d, speed: %d/%ld\n",
231 __func__, div_a, div_b, bus->input_freq, speed, speed_p);
233 writel((div_b << CDNS_I2C_CONTROL_DIV_B_SHIFT) |
234 (div_a << CDNS_I2C_CONTROL_DIV_A_SHIFT), &bus->regs->control);
236 /* Enable master mode, ack, and 7-bit addressing */
237 setbits_le32(&bus->regs->control, CDNS_I2C_CONTROL_MS |
238 CDNS_I2C_CONTROL_ACKEN | CDNS_I2C_CONTROL_NEA);
243 static inline u32 is_arbitration_lost(struct cdns_i2c_regs *regs)
245 return (readl(®s->interrupt_status) & CDNS_I2C_INTERRUPT_ARBLOST);
248 static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
252 struct cdns_i2c_regs *regs = i2c_bus->regs;
256 /* Set the controller in Master transmit mode and clear FIFO */
257 setbits_le32(®s->control, CDNS_I2C_CONTROL_CLR_FIFO);
258 clrbits_le32(®s->control, CDNS_I2C_CONTROL_RW);
261 * For sequential data load hold the bus.
264 setbits_le32(®s->control, CDNS_I2C_CONTROL_HOLD);
266 /* Clear the interrupts in status register */
267 writel(CDNS_I2C_INTERRUPTS_MASK, ®s->interrupt_status);
269 /* In case of Probe (i.e no data), start the transfer */
271 writel(addr, ®s->address);
273 while (len-- && !is_arbitration_lost(regs)) {
274 writel(*(cur_data++), ®s->data);
275 /* Trigger write only after loading data */
277 writel(addr, ®s->address);
280 if (len && readl(®s->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
281 ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
282 CDNS_I2C_INTERRUPT_ARBLOST);
283 if (ret & CDNS_I2C_INTERRUPT_ARBLOST)
285 if (ret & CDNS_I2C_INTERRUPT_COMP)
287 /* Release the bus */
288 clrbits_le32(®s->control,
289 CDNS_I2C_CONTROL_HOLD);
294 if (len && is_arbitration_lost(regs))
297 /* All done... release the bus */
298 if (!i2c_bus->hold_flag)
299 clrbits_le32(®s->control, CDNS_I2C_CONTROL_HOLD);
301 /* Wait for the address and data to be sent */
302 ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
303 CDNS_I2C_INTERRUPT_ARBLOST);
304 if (!(ret & (CDNS_I2C_INTERRUPT_ARBLOST |
305 CDNS_I2C_INTERRUPT_COMP)))
307 if (ret & CDNS_I2C_INTERRUPT_ARBLOST)
313 static inline bool cdns_is_hold_quirk(int hold_quirk, int curr_recv_count)
315 return hold_quirk && (curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1);
318 static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
322 struct cdns_i2c_regs *regs = i2c_bus->regs;
324 int updatetx, hold_quirk;
327 curr_recv_count = recv_count;
329 /* Check for the message size against the FIFO depth */
330 if (recv_count > CDNS_I2C_FIFO_DEPTH)
331 setbits_le32(®s->control, CDNS_I2C_CONTROL_HOLD);
333 setbits_le32(®s->control, CDNS_I2C_CONTROL_CLR_FIFO |
334 CDNS_I2C_CONTROL_RW);
336 if (recv_count > CDNS_I2C_TRANSFER_SIZE) {
337 curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
338 writel(curr_recv_count, ®s->transfer_size);
340 writel(recv_count, ®s->transfer_size);
343 /* Start reading data */
344 writel(addr, ®s->address);
346 updatetx = recv_count > curr_recv_count;
348 hold_quirk = (i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT) && updatetx;
350 while (recv_count && !is_arbitration_lost(regs)) {
351 while (readl(®s->status) & CDNS_I2C_STATUS_RXDV) {
352 if (recv_count < CDNS_I2C_FIFO_DEPTH &&
353 !i2c_bus->hold_flag) {
354 clrbits_le32(®s->control,
355 CDNS_I2C_CONTROL_HOLD);
357 *(cur_data)++ = readl(®s->data);
361 if (cdns_is_hold_quirk(hold_quirk, curr_recv_count))
365 if (cdns_is_hold_quirk(hold_quirk, curr_recv_count)) {
366 /* wait while fifo is full */
367 while (readl(®s->transfer_size) !=
368 (curr_recv_count - CDNS_I2C_FIFO_DEPTH))
371 * Check number of bytes to be received against maximum
372 * transfer size and update register accordingly.
374 if ((recv_count - CDNS_I2C_FIFO_DEPTH) >
375 CDNS_I2C_TRANSFER_SIZE) {
376 writel(CDNS_I2C_TRANSFER_SIZE,
377 ®s->transfer_size);
378 curr_recv_count = CDNS_I2C_TRANSFER_SIZE +
381 writel(recv_count - CDNS_I2C_FIFO_DEPTH,
382 ®s->transfer_size);
383 curr_recv_count = recv_count;
385 } else if (recv_count && !hold_quirk && !curr_recv_count) {
386 if (recv_count > CDNS_I2C_TRANSFER_SIZE) {
387 writel(CDNS_I2C_TRANSFER_SIZE,
388 ®s->transfer_size);
389 curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
391 writel(recv_count, ®s->transfer_size);
392 curr_recv_count = recv_count;
394 writel(addr, ®s->address);
398 /* Wait for the address and data to be sent */
399 ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
400 CDNS_I2C_INTERRUPT_ARBLOST);
401 if (!(ret & (CDNS_I2C_INTERRUPT_ARBLOST |
402 CDNS_I2C_INTERRUPT_COMP)))
404 if (ret & CDNS_I2C_INTERRUPT_ARBLOST)
410 static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
413 struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
417 struct i2c_msg *message = msg;
418 int num_msgs = nmsgs;
420 hold_quirk = !!(i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT);
424 * This controller does not give completion interrupt after a
425 * master receive message if HOLD bit is set (repeated start),
426 * resulting in SW timeout. Hence, if a receive message is
427 * followed by any other message, an error is returned
428 * indicating that this sequence is not supported.
430 for (count = 0; (count < nmsgs - 1) && hold_quirk; count++) {
431 if (msg[count].flags & I2C_M_RD) {
432 printf("Can't do repeated start after a receive message\n");
437 i2c_bus->hold_flag = 1;
438 setbits_le32(&i2c_bus->regs->control, CDNS_I2C_CONTROL_HOLD);
440 i2c_bus->hold_flag = 0;
443 debug("i2c_xfer: %d messages\n", nmsgs);
444 for (u8 retry = 0; retry < CDNS_I2C_ARB_LOST_MAX_RETRIES &&
445 nmsgs > 0; nmsgs--, msg++) {
446 debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
447 if (msg->flags & I2C_M_RD) {
448 ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf,
451 ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf,
454 if (ret == -EAGAIN) {
458 printf("%s,arbitration lost, retrying:%d\n", __func__,
464 debug("i2c_write: error sending\n");
472 static int cdns_i2c_of_to_plat(struct udevice *dev)
474 struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
475 struct cdns_i2c_platform_data *pdata =
476 (struct cdns_i2c_platform_data *)dev_get_driver_data(dev);
480 i2c_bus->regs = (struct cdns_i2c_regs *)dev_read_addr(dev);
485 i2c_bus->quirks = pdata->quirks;
487 ret = clk_get_by_index(dev, 0, &clk);
491 i2c_bus->input_freq = clk_get_rate(&clk);
493 ret = clk_enable(&clk);
495 dev_err(dev, "failed to enable clock\n");
502 static const struct dm_i2c_ops cdns_i2c_ops = {
503 .xfer = cdns_i2c_xfer,
504 .set_bus_speed = cdns_i2c_set_bus_speed,
507 static const struct cdns_i2c_platform_data r1p10_i2c_def = {
508 .quirks = CDNS_I2C_BROKEN_HOLD_BIT,
511 static const struct udevice_id cdns_i2c_of_match[] = {
512 { .compatible = "cdns,i2c-r1p10", .data = (ulong)&r1p10_i2c_def },
513 { .compatible = "cdns,i2c-r1p14" },
514 { /* end of table */ }
517 U_BOOT_DRIVER(cdns_i2c) = {
520 .of_match = cdns_i2c_of_match,
521 .of_to_plat = cdns_i2c_of_to_plat,
522 .priv_auto = sizeof(struct i2c_cdns_bus),
523 .ops = &cdns_i2c_ops,