1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (c) 2016, Google Inc
4 *
5 * (C) Copyright 2002
6 * David Mueller, ELSOFT AG, d.mueller@elsoft.ch
7 */
8
9 #include <common.h>
10 #include <dm.h>
11 #include <i2c.h>
12 #include <asm/arch/clk.h>
13 #include <asm/arch/cpu.h>
14 #include <asm/arch/pinmux.h>
15 #include "s3c24x0_i2c.h"
16
17 DECLARE_GLOBAL_DATA_PTR;
18
19 /* HSI2C-specific register description */
20
21 /* I2C_CTL Register bits */
22 #define HSI2C_FUNC_MODE_I2C (1u << 0)
23 #define HSI2C_MASTER (1u << 3)
24 #define HSI2C_RXCHON (1u << 6) /* Write/Send */
25 #define HSI2C_TXCHON (1u << 7) /* Read/Receive */
26 #define HSI2C_SW_RST (1u << 31)
27
28 /* I2C_FIFO_CTL Register bits */
29 #define HSI2C_RXFIFO_EN (1u << 0)
30 #define HSI2C_TXFIFO_EN (1u << 1)
31 #define HSI2C_TXFIFO_TRIGGER_LEVEL (0x20 << 16)
32 #define HSI2C_RXFIFO_TRIGGER_LEVEL (0x20 << 4)
33
34 /* I2C_TRAILING_CTL Register bits */
35 #define HSI2C_TRAILING_COUNT (0xff)
36
37 /* I2C_INT_EN Register bits */
38 #define HSI2C_TX_UNDERRUN_EN (1u << 2)
39 #define HSI2C_TX_OVERRUN_EN (1u << 3)
40 #define HSI2C_RX_UNDERRUN_EN (1u << 4)
41 #define HSI2C_RX_OVERRUN_EN (1u << 5)
42 #define HSI2C_INT_TRAILING_EN (1u << 6)
43 #define HSI2C_INT_I2C_EN (1u << 9)
44
45 #define HSI2C_INT_ERROR_MASK (HSI2C_TX_UNDERRUN_EN |\
46 HSI2C_TX_OVERRUN_EN |\
47 HSI2C_RX_UNDERRUN_EN |\
48 HSI2C_RX_OVERRUN_EN |\
49 HSI2C_INT_TRAILING_EN)
50
51 /* I2C_CONF Register bits */
52 #define HSI2C_AUTO_MODE (1u << 31)
53 #define HSI2C_10BIT_ADDR_MODE (1u << 30)
54 #define HSI2C_HS_MODE (1u << 29)
55
56 /* I2C_AUTO_CONF Register bits */
57 #define HSI2C_READ_WRITE (1u << 16)
58 #define HSI2C_STOP_AFTER_TRANS (1u << 17)
59 #define HSI2C_MASTER_RUN (1u << 31)
60
61 /* I2C_TIMEOUT Register bits */
62 #define HSI2C_TIMEOUT_EN (1u << 31)
63
64 /* I2C_TRANS_STATUS register bits */
65 #define HSI2C_MASTER_BUSY (1u << 17)
66 #define HSI2C_SLAVE_BUSY (1u << 16)
67 #define HSI2C_TIMEOUT_AUTO (1u << 4)
68 #define HSI2C_NO_DEV (1u << 3)
69 #define HSI2C_NO_DEV_ACK (1u << 2)
70 #define HSI2C_TRANS_ABORT (1u << 1)
71 #define HSI2C_TRANS_SUCCESS (1u << 0)
72 #define HSI2C_TRANS_ERROR_MASK (HSI2C_TIMEOUT_AUTO |\
73 HSI2C_NO_DEV | HSI2C_NO_DEV_ACK |\
74 HSI2C_TRANS_ABORT)
75 #define HSI2C_TRANS_FINISHED_MASK (HSI2C_TRANS_ERROR_MASK | HSI2C_TRANS_SUCCESS)
76
77
78 /* I2C_FIFO_STAT Register bits */
79 #define HSI2C_RX_FIFO_EMPTY (1u << 24)
80 #define HSI2C_RX_FIFO_FULL (1u << 23)
81 #define HSI2C_TX_FIFO_EMPTY (1u << 8)
82 #define HSI2C_TX_FIFO_FULL (1u << 7)
83 #define HSI2C_RX_FIFO_LEVEL(x) (((x) >> 16) & 0x7f)
84 #define HSI2C_TX_FIFO_LEVEL(x) ((x) & 0x7f)
85
86 #define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10)
87
88 #define HSI2C_TIMEOUT_US 10000 /* 10 ms, finer granularity */
89
90 /*
91 * Wait for transfer completion.
92 *
93 * This function reads the interrupt status register waiting for the INT_I2C
94 * bit to be set, which indicates copletion of a transaction.
95 *
96 * @param i2c: pointer to the appropriate register bank
97 *
98 * @return: I2C_OK in case of successful completion, I2C_NOK_TIMEOUT in case
99 * the status bits do not get set in time, or an approrpiate error
100 * value in case of transfer errors.
101 */
hsi2c_wait_for_trx(struct exynos5_hsi2c * i2c)102 static int hsi2c_wait_for_trx(struct exynos5_hsi2c *i2c)
103 {
104 int i = HSI2C_TIMEOUT_US;
105
106 while (i-- > 0) {
107 u32 int_status = readl(&i2c->usi_int_stat);
108
109 if (int_status & HSI2C_INT_I2C_EN) {
110 u32 trans_status = readl(&i2c->usi_trans_status);
111
112 /* Deassert pending interrupt. */
113 writel(int_status, &i2c->usi_int_stat);
114
115 if (trans_status & HSI2C_NO_DEV_ACK) {
116 debug("%s: no ACK from device\n", __func__);
117 return I2C_NACK;
118 }
119 if (trans_status & HSI2C_NO_DEV) {
120 debug("%s: no device\n", __func__);
121 return I2C_NOK;
122 }
123 if (trans_status & HSI2C_TRANS_ABORT) {
124 debug("%s: arbitration lost\n", __func__);
125 return I2C_NOK_LA;
126 }
127 if (trans_status & HSI2C_TIMEOUT_AUTO) {
128 debug("%s: device timed out\n", __func__);
129 return I2C_NOK_TOUT;
130 }
131 return I2C_OK;
132 }
133 udelay(1);
134 }
135 debug("%s: transaction timeout!\n", __func__);
136 return I2C_NOK_TOUT;
137 }
138
hsi2c_get_clk_details(struct s3c24x0_i2c_bus * i2c_bus)139 static int hsi2c_get_clk_details(struct s3c24x0_i2c_bus *i2c_bus)
140 {
141 struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
142 ulong clkin;
143 unsigned int op_clk = i2c_bus->clock_frequency;
144 unsigned int i = 0, utemp0 = 0, utemp1 = 0;
145 unsigned int t_ftl_cycle;
146
147 #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
148 clkin = get_i2c_clk();
149 #else
150 clkin = get_PCLK();
151 #endif
152 /* FPCLK / FI2C =
153 * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE
154 * uTemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2)
155 * uTemp1 = (TSCLK_L + TSCLK_H + 2)
156 * uTemp2 = TSCLK_L + TSCLK_H
157 */
158 t_ftl_cycle = (readl(&hsregs->usi_conf) >> 16) & 0x7;
159 utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle;
160
161 /* CLK_DIV max is 256 */
162 for (i = 0; i < 256; i++) {
163 utemp1 = utemp0 / (i + 1);
164 if ((utemp1 < 512) && (utemp1 > 4)) {
165 i2c_bus->clk_cycle = utemp1 - 2;
166 i2c_bus->clk_div = i;
167 return 0;
168 }
169 }
170 return -EINVAL;
171 }
172
hsi2c_ch_init(struct s3c24x0_i2c_bus * i2c_bus)173 static void hsi2c_ch_init(struct s3c24x0_i2c_bus *i2c_bus)
174 {
175 struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
176 unsigned int t_sr_release;
177 unsigned int n_clkdiv;
178 unsigned int t_start_su, t_start_hd;
179 unsigned int t_stop_su;
180 unsigned int t_data_su, t_data_hd;
181 unsigned int t_scl_l, t_scl_h;
182 u32 i2c_timing_s1;
183 u32 i2c_timing_s2;
184 u32 i2c_timing_s3;
185 u32 i2c_timing_sla;
186
187 n_clkdiv = i2c_bus->clk_div;
188 t_scl_l = i2c_bus->clk_cycle / 2;
189 t_scl_h = i2c_bus->clk_cycle / 2;
190 t_start_su = t_scl_l;
191 t_start_hd = t_scl_l;
192 t_stop_su = t_scl_l;
193 t_data_su = t_scl_l / 2;
194 t_data_hd = t_scl_l / 2;
195 t_sr_release = i2c_bus->clk_cycle;
196
197 i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8;
198 i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0;
199 i2c_timing_s3 = n_clkdiv << 16 | t_sr_release << 0;
200 i2c_timing_sla = t_data_hd << 0;
201
202 writel(HSI2C_TRAILING_COUNT, &hsregs->usi_trailing_ctl);
203
204 /* Clear to enable Timeout */
205 clrsetbits_le32(&hsregs->usi_timeout, HSI2C_TIMEOUT_EN, 0);
206
207 /* set AUTO mode */
208 writel(readl(&hsregs->usi_conf) | HSI2C_AUTO_MODE, &hsregs->usi_conf);
209
210 /* Enable completion conditions' reporting. */
211 writel(HSI2C_INT_I2C_EN, &hsregs->usi_int_en);
212
213 /* Enable FIFOs */
214 writel(HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN, &hsregs->usi_fifo_ctl);
215
216 /* Currently operating in Fast speed mode. */
217 writel(i2c_timing_s1, &hsregs->usi_timing_fs1);
218 writel(i2c_timing_s2, &hsregs->usi_timing_fs2);
219 writel(i2c_timing_s3, &hsregs->usi_timing_fs3);
220 writel(i2c_timing_sla, &hsregs->usi_timing_sla);
221 }
222
223 /* SW reset for the high speed bus */
exynos5_i2c_reset(struct s3c24x0_i2c_bus * i2c_bus)224 static void exynos5_i2c_reset(struct s3c24x0_i2c_bus *i2c_bus)
225 {
226 struct exynos5_hsi2c *i2c = i2c_bus->hsregs;
227 u32 i2c_ctl;
228
229 /* Set and clear the bit for reset */
230 i2c_ctl = readl(&i2c->usi_ctl);
231 i2c_ctl |= HSI2C_SW_RST;
232 writel(i2c_ctl, &i2c->usi_ctl);
233
234 i2c_ctl = readl(&i2c->usi_ctl);
235 i2c_ctl &= ~HSI2C_SW_RST;
236 writel(i2c_ctl, &i2c->usi_ctl);
237
238 /* Initialize the configure registers */
239 hsi2c_ch_init(i2c_bus);
240 }
241
242 /*
243 * Poll the appropriate bit of the fifo status register until the interface is
244 * ready to process the next byte or timeout expires.
245 *
246 * In addition to the FIFO status register this function also polls the
247 * interrupt status register to be able to detect unexpected transaction
248 * completion.
249 *
250 * When FIFO is ready to process the next byte, this function returns I2C_OK.
251 * If in course of polling the INT_I2C assertion is detected, the function
252 * returns I2C_NOK. If timeout happens before any of the above conditions is
253 * met - the function returns I2C_NOK_TOUT;
254
255 * @param i2c: pointer to the appropriate i2c register bank.
256 * @param rx_transfer: set to True if the receive transaction is in progress.
257 * @return: as described above.
258 */
hsi2c_poll_fifo(struct exynos5_hsi2c * i2c,bool rx_transfer)259 static unsigned hsi2c_poll_fifo(struct exynos5_hsi2c *i2c, bool rx_transfer)
260 {
261 u32 fifo_bit = rx_transfer ? HSI2C_RX_FIFO_EMPTY : HSI2C_TX_FIFO_FULL;
262 int i = HSI2C_TIMEOUT_US;
263
264 while (readl(&i2c->usi_fifo_stat) & fifo_bit) {
265 if (readl(&i2c->usi_int_stat) & HSI2C_INT_I2C_EN) {
266 /*
267 * There is a chance that assertion of
268 * HSI2C_INT_I2C_EN and deassertion of
269 * HSI2C_RX_FIFO_EMPTY happen simultaneously. Let's
270 * give FIFO status priority and check it one more
271 * time before reporting interrupt. The interrupt will
272 * be reported next time this function is called.
273 */
274 if (rx_transfer &&
275 !(readl(&i2c->usi_fifo_stat) & fifo_bit))
276 break;
277 return I2C_NOK;
278 }
279 if (!i--) {
280 debug("%s: FIFO polling timeout!\n", __func__);
281 return I2C_NOK_TOUT;
282 }
283 udelay(1);
284 }
285 return I2C_OK;
286 }
287
288 /*
289 * Preapre hsi2c transaction, either read or write.
290 *
291 * Set up transfer as described in section 27.5.1.2 'I2C Channel Auto Mode' of
292 * the 5420 UM.
293 *
294 * @param i2c: pointer to the appropriate i2c register bank.
295 * @param chip: slave address on the i2c bus (with read/write bit exlcuded)
296 * @param len: number of bytes expected to be sent or received
297 * @param rx_transfer: set to true for receive transactions
298 * @param: issue_stop: set to true if i2c stop condition should be generated
299 * after this transaction.
300 * @return: I2C_NOK_TOUT in case the bus remained busy for HSI2C_TIMEOUT_US,
301 * I2C_OK otherwise.
302 */
hsi2c_prepare_transaction(struct exynos5_hsi2c * i2c,u8 chip,u16 len,bool rx_transfer,bool issue_stop)303 static int hsi2c_prepare_transaction(struct exynos5_hsi2c *i2c,
304 u8 chip,
305 u16 len,
306 bool rx_transfer,
307 bool issue_stop)
308 {
309 u32 conf;
310
311 conf = len | HSI2C_MASTER_RUN;
312
313 if (issue_stop)
314 conf |= HSI2C_STOP_AFTER_TRANS;
315
316 /* Clear to enable Timeout */
317 writel(readl(&i2c->usi_timeout) & ~HSI2C_TIMEOUT_EN, &i2c->usi_timeout);
318
319 /* Set slave address */
320 writel(HSI2C_SLV_ADDR_MAS(chip), &i2c->i2c_addr);
321
322 if (rx_transfer) {
323 /* i2c master, read transaction */
324 writel((HSI2C_RXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
325 &i2c->usi_ctl);
326
327 /* read up to len bytes, stop after transaction is finished */
328 writel(conf | HSI2C_READ_WRITE, &i2c->usi_auto_conf);
329 } else {
330 /* i2c master, write transaction */
331 writel((HSI2C_TXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
332 &i2c->usi_ctl);
333
334 /* write up to len bytes, stop after transaction is finished */
335 writel(conf, &i2c->usi_auto_conf);
336 }
337
338 /* Reset all pending interrupt status bits we care about, if any */
339 writel(HSI2C_INT_I2C_EN, &i2c->usi_int_stat);
340
341 return I2C_OK;
342 }
343
344 /*
345 * Wait while i2c bus is settling down (mostly stop gets completed).
346 */
hsi2c_wait_while_busy(struct exynos5_hsi2c * i2c)347 static int hsi2c_wait_while_busy(struct exynos5_hsi2c *i2c)
348 {
349 int i = HSI2C_TIMEOUT_US;
350
351 while (readl(&i2c->usi_trans_status) & HSI2C_MASTER_BUSY) {
352 if (!i--) {
353 debug("%s: bus busy\n", __func__);
354 return I2C_NOK_TOUT;
355 }
356 udelay(1);
357 }
358 return I2C_OK;
359 }
360
hsi2c_write(struct exynos5_hsi2c * i2c,unsigned char chip,unsigned char addr[],unsigned char alen,unsigned char data[],unsigned short len,bool issue_stop)361 static int hsi2c_write(struct exynos5_hsi2c *i2c,
362 unsigned char chip,
363 unsigned char addr[],
364 unsigned char alen,
365 unsigned char data[],
366 unsigned short len,
367 bool issue_stop)
368 {
369 int i, rv = 0;
370
371 if (!(len + alen)) {
372 /* Writes of zero length not supported in auto mode. */
373 debug("%s: zero length writes not supported\n", __func__);
374 return I2C_NOK;
375 }
376
377 rv = hsi2c_prepare_transaction
378 (i2c, chip, len + alen, false, issue_stop);
379 if (rv != I2C_OK)
380 return rv;
381
382 /* Move address, if any, and the data, if any, into the FIFO. */
383 for (i = 0; i < alen; i++) {
384 rv = hsi2c_poll_fifo(i2c, false);
385 if (rv != I2C_OK) {
386 debug("%s: address write failed\n", __func__);
387 goto write_error;
388 }
389 writel(addr[i], &i2c->usi_txdata);
390 }
391
392 for (i = 0; i < len; i++) {
393 rv = hsi2c_poll_fifo(i2c, false);
394 if (rv != I2C_OK) {
395 debug("%s: data write failed\n", __func__);
396 goto write_error;
397 }
398 writel(data[i], &i2c->usi_txdata);
399 }
400
401 rv = hsi2c_wait_for_trx(i2c);
402
403 write_error:
404 if (issue_stop) {
405 int tmp_ret = hsi2c_wait_while_busy(i2c);
406 if (rv == I2C_OK)
407 rv = tmp_ret;
408 }
409
410 writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
411 return rv;
412 }
413
hsi2c_read(struct exynos5_hsi2c * i2c,unsigned char chip,unsigned char addr[],unsigned char alen,unsigned char data[],unsigned short len)414 static int hsi2c_read(struct exynos5_hsi2c *i2c,
415 unsigned char chip,
416 unsigned char addr[],
417 unsigned char alen,
418 unsigned char data[],
419 unsigned short len)
420 {
421 int i, rv, tmp_ret;
422 bool drop_data = false;
423
424 if (!len) {
425 /* Reads of zero length not supported in auto mode. */
426 debug("%s: zero length read adjusted\n", __func__);
427 drop_data = true;
428 len = 1;
429 }
430
431 if (alen) {
432 /* Internal register adress needs to be written first. */
433 rv = hsi2c_write(i2c, chip, addr, alen, NULL, 0, false);
434 if (rv != I2C_OK)
435 return rv;
436 }
437
438 rv = hsi2c_prepare_transaction(i2c, chip, len, true, true);
439
440 if (rv != I2C_OK)
441 return rv;
442
443 for (i = 0; i < len; i++) {
444 rv = hsi2c_poll_fifo(i2c, true);
445 if (rv != I2C_OK)
446 goto read_err;
447 if (drop_data)
448 continue;
449 data[i] = readl(&i2c->usi_rxdata);
450 }
451
452 rv = hsi2c_wait_for_trx(i2c);
453
454 read_err:
455 tmp_ret = hsi2c_wait_while_busy(i2c);
456 if (rv == I2C_OK)
457 rv = tmp_ret;
458
459 writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
460 return rv;
461 }
462
exynos_hs_i2c_xfer(struct udevice * dev,struct i2c_msg * msg,int nmsgs)463 static int exynos_hs_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
464 int nmsgs)
465 {
466 struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
467 struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
468 int ret;
469
470 for (; nmsgs > 0; nmsgs--, msg++) {
471 if (msg->flags & I2C_M_RD) {
472 ret = hsi2c_read(hsregs, msg->addr, 0, 0, msg->buf,
473 msg->len);
474 } else {
475 ret = hsi2c_write(hsregs, msg->addr, 0, 0, msg->buf,
476 msg->len, true);
477 }
478 if (ret) {
479 exynos5_i2c_reset(i2c_bus);
480 return -EREMOTEIO;
481 }
482 }
483
484 return 0;
485 }
486
s3c24x0_i2c_set_bus_speed(struct udevice * dev,unsigned int speed)487 static int s3c24x0_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
488 {
489 struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
490
491 i2c_bus->clock_frequency = speed;
492
493 if (hsi2c_get_clk_details(i2c_bus))
494 return -EFAULT;
495 hsi2c_ch_init(i2c_bus);
496
497 return 0;
498 }
499
s3c24x0_i2c_probe(struct udevice * dev,uint chip,uint chip_flags)500 static int s3c24x0_i2c_probe(struct udevice *dev, uint chip, uint chip_flags)
501 {
502 struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
503 uchar buf[1];
504 int ret;
505
506 buf[0] = 0;
507
508 /*
509 * What is needed is to send the chip address and verify that the
510 * address was <ACK>ed (i.e. there was a chip at that address which
511 * drove the data line low).
512 */
513 ret = hsi2c_read(i2c_bus->hsregs, chip, 0, 0, buf, 1);
514
515 return ret != I2C_OK;
516 }
517
s3c_i2c_ofdata_to_platdata(struct udevice * dev)518 static int s3c_i2c_ofdata_to_platdata(struct udevice *dev)
519 {
520 const void *blob = gd->fdt_blob;
521 struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
522 int node;
523
524 node = dev_of_offset(dev);
525
526 i2c_bus->hsregs = (struct exynos5_hsi2c *)devfdt_get_addr(dev);
527
528 i2c_bus->id = pinmux_decode_periph_id(blob, node);
529
530 i2c_bus->clock_frequency = fdtdec_get_int(blob, node,
531 "clock-frequency", 100000);
532 i2c_bus->node = node;
533 i2c_bus->bus_num = dev->seq;
534
535 exynos_pinmux_config(i2c_bus->id, PINMUX_FLAG_HS_MODE);
536
537 i2c_bus->active = true;
538
539 return 0;
540 }
541
542 static const struct dm_i2c_ops exynos_hs_i2c_ops = {
543 .xfer = exynos_hs_i2c_xfer,
544 .probe_chip = s3c24x0_i2c_probe,
545 .set_bus_speed = s3c24x0_i2c_set_bus_speed,
546 };
547
548 static const struct udevice_id exynos_hs_i2c_ids[] = {
549 { .compatible = "samsung,exynos5-hsi2c" },
550 { }
551 };
552
553 U_BOOT_DRIVER(hs_i2c) = {
554 .name = "i2c_s3c_hs",
555 .id = UCLASS_I2C,
556 .of_match = exynos_hs_i2c_ids,
557 .ofdata_to_platdata = s3c_i2c_ofdata_to_platdata,
558 .priv_auto_alloc_size = sizeof(struct s3c24x0_i2c_bus),
559 .ops = &exynos_hs_i2c_ops,
560 };
561