1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
7 #include <linux/mod_devicetable.h>
8 #include <linux/module.h>
9 #include <linux/platform_device.h>
10 #include <linux/regmap.h>
11 #include <linux/mfd/syscon.h>
13 #define GXP_MAX_I2C_ENGINE 10
14 static const char * const gxp_i2c_name[] = {
15 "gxp-i2c0", "gxp-i2c1", "gxp-i2c2", "gxp-i2c3",
16 "gxp-i2c4", "gxp-i2c5", "gxp-i2c6", "gxp-i2c7",
17 "gxp-i2c8", "gxp-i2c9" };
19 /* GXP I2C Global interrupt status/enable register*/
20 #define GXP_I2CINTSTAT 0x00
21 #define GXP_I2CINTEN 0x04
23 /* GXP I2C registers */
24 #define GXP_I2CSTAT 0x00
25 #define MASK_STOP_EVENT 0x20
28 #define GXP_I2CEVTERR 0x01
29 #define MASK_SLAVE_CMD_EVENT 0x01
30 #define MASK_SLAVE_DATA_EVENT 0x02
31 #define MASK_MASTER_EVENT 0x10
32 #define GXP_I2CSNPDAT 0x02
33 #define GXP_I2CMCMD 0x04
34 #define GXP_I2CSCMD 0x06
35 #define GXP_I2CSNPAA 0x09
36 #define GXP_I2CADVFEAT 0x0A
37 #define GXP_I2COWNADR 0x0B
38 #define GXP_I2CFREQDIV 0x0C
39 #define GXP_I2CFLTFAIR 0x0D
40 #define GXP_I2CTMOEDG 0x0E
41 #define GXP_I2CCYCTIM 0x0F
44 #define SNOOP_EVT_CLR 0x80
45 #define SLAVE_EVT_CLR 0x40
46 #define SNOOP_EVT_MASK 0x20
47 #define SLAVE_EVT_MASK 0x10
48 #define SLAVE_ACK_ENAB 0x08
49 #define SLAVE_EVT_STALL 0x01
52 #define MASTER_EVT_CLR 0x80
53 #define MASTER_ACK_ENAB 0x08
56 #define START_CMD 0x01
59 #define GXP_DATA_EDGE_RST_CTRL 0x0a /* 30ns */
62 #define FILTER_CNT 0x30
63 #define FAIRNESS_CNT 0x02
76 struct gxp_i2c_drvdata {
82 struct completion completion;
83 struct i2c_adapter adapter;
84 struct i2c_msg *curr_msg;
90 struct i2c_client *slave;
91 unsigned char stopped;
94 static struct regmap *i2cg_map;
96 static void gxp_i2c_start(struct gxp_i2c_drvdata *drvdata)
100 drvdata->buf = drvdata->curr_msg->buf;
101 drvdata->buf_remaining = drvdata->curr_msg->len;
103 /* Note: Address in struct i2c_msg is 7 bits */
104 value = drvdata->curr_msg->addr << 9;
107 value |= drvdata->curr_msg->flags & I2C_M_RD ? RW_CMD | START_CMD : START_CMD;
109 drvdata->state = GXP_I2C_ADDR_PHASE;
110 writew(value, drvdata->base + GXP_I2CMCMD);
113 static int gxp_i2c_master_xfer(struct i2c_adapter *adapter,
114 struct i2c_msg *msgs, int num)
117 struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(adapter);
118 unsigned long time_left;
120 drvdata->msgs_remaining = num;
121 drvdata->curr_msg = msgs;
122 drvdata->msgs_num = num;
123 reinit_completion(&drvdata->completion);
125 gxp_i2c_start(drvdata);
127 time_left = wait_for_completion_timeout(&drvdata->completion,
129 ret = num - drvdata->msgs_remaining;
133 if (drvdata->state == GXP_I2C_ADDR_NACK)
136 if (drvdata->state == GXP_I2C_DATA_NACK)
142 static u32 gxp_i2c_func(struct i2c_adapter *adap)
144 if (IS_ENABLED(CONFIG_I2C_SLAVE))
145 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE;
147 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
150 #if IS_ENABLED(CONFIG_I2C_SLAVE)
151 static int gxp_i2c_reg_slave(struct i2c_client *slave)
153 struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter);
158 if (slave->flags & I2C_CLIENT_TEN)
159 return -EAFNOSUPPORT;
161 drvdata->slave = slave;
163 writeb(slave->addr << 1, drvdata->base + GXP_I2COWNADR);
164 writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK | SLAVE_ACK_ENAB |
165 SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
170 static int gxp_i2c_unreg_slave(struct i2c_client *slave)
172 struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter);
174 WARN_ON(!drvdata->slave);
176 writeb(0x00, drvdata->base + GXP_I2COWNADR);
177 writeb(SNOOP_EVT_CLR | SLAVE_EVT_CLR | SNOOP_EVT_MASK |
178 SLAVE_EVT_MASK, drvdata->base + GXP_I2CSCMD);
180 drvdata->slave = NULL;
186 static const struct i2c_algorithm gxp_i2c_algo = {
187 .master_xfer = gxp_i2c_master_xfer,
188 .functionality = gxp_i2c_func,
189 #if IS_ENABLED(CONFIG_I2C_SLAVE)
190 .reg_slave = gxp_i2c_reg_slave,
191 .unreg_slave = gxp_i2c_unreg_slave,
195 static void gxp_i2c_stop(struct gxp_i2c_drvdata *drvdata)
197 /* Clear event and send stop */
198 writeb(MASTER_EVT_CLR | STOP_CMD, drvdata->base + GXP_I2CMCMD);
200 complete(&drvdata->completion);
203 static void gxp_i2c_restart(struct gxp_i2c_drvdata *drvdata)
207 drvdata->buf = drvdata->curr_msg->buf;
208 drvdata->buf_remaining = drvdata->curr_msg->len;
210 value = drvdata->curr_msg->addr << 9;
212 if (drvdata->curr_msg->flags & I2C_M_RD) {
213 /* Read and clear master event */
214 value |= MASTER_EVT_CLR | RW_CMD | START_CMD;
216 /* Write and clear master event */
217 value |= MASTER_EVT_CLR | START_CMD;
220 drvdata->state = GXP_I2C_ADDR_PHASE;
222 writew(value, drvdata->base + GXP_I2CMCMD);
225 static void gxp_i2c_chk_addr_ack(struct gxp_i2c_drvdata *drvdata)
229 value = readb(drvdata->base + GXP_I2CSTAT);
230 if (!(value & MASK_ACK)) {
231 /* Got no ack, stop */
232 drvdata->state = GXP_I2C_ADDR_NACK;
233 gxp_i2c_stop(drvdata);
237 if (drvdata->curr_msg->flags & I2C_M_RD) {
238 /* Start to read data from slave */
239 if (drvdata->buf_remaining == 0) {
240 /* No more data to read, stop */
241 drvdata->msgs_remaining--;
242 drvdata->state = GXP_I2C_COMP;
243 gxp_i2c_stop(drvdata);
246 drvdata->state = GXP_I2C_RDATA_PHASE;
248 if (drvdata->buf_remaining == 1) {
249 /* The last data, do not ack */
250 writeb(MASTER_EVT_CLR | RW_CMD,
251 drvdata->base + GXP_I2CMCMD);
253 /* Read data and ack it */
254 writeb(MASTER_EVT_CLR | MASTER_ACK_ENAB |
255 RW_CMD, drvdata->base + GXP_I2CMCMD);
258 /* Start to write first data to slave */
259 if (drvdata->buf_remaining == 0) {
260 /* No more data to write, stop */
261 drvdata->msgs_remaining--;
262 drvdata->state = GXP_I2C_COMP;
263 gxp_i2c_stop(drvdata);
266 value = *drvdata->buf;
268 /* Clear master event */
269 value |= MASTER_EVT_CLR;
271 drvdata->buf_remaining--;
272 drvdata->state = GXP_I2C_WDATA_PHASE;
273 writew(value, drvdata->base + GXP_I2CMCMD);
277 static void gxp_i2c_ack_data(struct gxp_i2c_drvdata *drvdata)
281 /* Store the data returned */
282 value = readb(drvdata->base + GXP_I2CSNPDAT);
283 *drvdata->buf = value;
285 drvdata->buf_remaining--;
287 if (drvdata->buf_remaining == 0) {
288 /* No more data, this message is completed. */
289 drvdata->msgs_remaining--;
291 if (drvdata->msgs_remaining == 0) {
292 /* No more messages, stop */
293 drvdata->state = GXP_I2C_COMP;
294 gxp_i2c_stop(drvdata);
297 /* Move to next message and start transfer */
299 gxp_i2c_restart(drvdata);
303 /* Ack the slave to make it send next byte */
304 drvdata->state = GXP_I2C_RDATA_PHASE;
305 if (drvdata->buf_remaining == 1) {
306 /* The last data, do not ack */
307 writeb(MASTER_EVT_CLR | RW_CMD,
308 drvdata->base + GXP_I2CMCMD);
310 /* Read data and ack it */
311 writeb(MASTER_EVT_CLR | MASTER_ACK_ENAB |
312 RW_CMD, drvdata->base + GXP_I2CMCMD);
316 static void gxp_i2c_chk_data_ack(struct gxp_i2c_drvdata *drvdata)
320 value = readb(drvdata->base + GXP_I2CSTAT);
321 if (!(value & MASK_ACK)) {
322 /* Received No ack, stop */
323 drvdata->state = GXP_I2C_DATA_NACK;
324 gxp_i2c_stop(drvdata);
328 /* Got ack, check if there is more data to write */
329 if (drvdata->buf_remaining == 0) {
330 /* No more data, this message is completed */
331 drvdata->msgs_remaining--;
333 if (drvdata->msgs_remaining == 0) {
334 /* No more messages, stop */
335 drvdata->state = GXP_I2C_COMP;
336 gxp_i2c_stop(drvdata);
339 /* Move to next message and start transfer */
341 gxp_i2c_restart(drvdata);
345 /* Write data to slave */
346 value = *drvdata->buf;
349 /* Clear master event */
350 value |= MASTER_EVT_CLR;
352 drvdata->buf_remaining--;
353 drvdata->state = GXP_I2C_WDATA_PHASE;
354 writew(value, drvdata->base + GXP_I2CMCMD);
357 static bool gxp_i2c_slave_irq_handler(struct gxp_i2c_drvdata *drvdata)
363 value = readb(drvdata->base + GXP_I2CEVTERR);
365 /* Received start or stop event */
366 if (value & MASK_SLAVE_CMD_EVENT) {
367 value = readb(drvdata->base + GXP_I2CSTAT);
368 /* Master sent stop */
369 if (value & MASK_STOP_EVENT) {
370 if (drvdata->stopped == 0)
371 i2c_slave_event(drvdata->slave, I2C_SLAVE_STOP, &buf);
372 writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
373 SLAVE_ACK_ENAB | SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
374 drvdata->stopped = 1;
376 /* Master sent start and wants to read */
377 drvdata->stopped = 0;
378 if (value & MASK_RW) {
379 i2c_slave_event(drvdata->slave,
380 I2C_SLAVE_READ_REQUESTED, &buf);
381 value = buf << 8 | (SLAVE_EVT_CLR | SNOOP_EVT_MASK |
383 writew(value, drvdata->base + GXP_I2CSCMD);
385 /* Master wants to write to us */
386 ret = i2c_slave_event(drvdata->slave,
387 I2C_SLAVE_WRITE_REQUESTED, &buf);
389 /* Ack next byte from master */
390 writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
391 SLAVE_ACK_ENAB | SLAVE_EVT_STALL,
392 drvdata->base + GXP_I2CSCMD);
394 /* Nack next byte from master */
395 writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
396 SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
400 } else if (value & MASK_SLAVE_DATA_EVENT) {
401 value = readb(drvdata->base + GXP_I2CSTAT);
402 /* Master wants to read */
403 if (value & MASK_RW) {
404 /* Master wants another byte */
405 if (value & MASK_ACK) {
406 i2c_slave_event(drvdata->slave,
407 I2C_SLAVE_READ_PROCESSED, &buf);
408 value = buf << 8 | (SLAVE_EVT_CLR | SNOOP_EVT_MASK |
410 writew(value, drvdata->base + GXP_I2CSCMD);
412 /* No more bytes needed */
413 writew(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
414 SLAVE_ACK_ENAB | SLAVE_EVT_STALL,
415 drvdata->base + GXP_I2CSCMD);
418 /* Master wants to write to us */
419 value = readb(drvdata->base + GXP_I2CSNPDAT);
420 buf = (uint8_t)value;
421 ret = i2c_slave_event(drvdata->slave,
422 I2C_SLAVE_WRITE_RECEIVED, &buf);
424 /* Ack next byte from master */
425 writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
426 SLAVE_ACK_ENAB | SLAVE_EVT_STALL,
427 drvdata->base + GXP_I2CSCMD);
429 /* Nack next byte from master */
430 writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
431 SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
441 static irqreturn_t gxp_i2c_irq_handler(int irq, void *_drvdata)
443 struct gxp_i2c_drvdata *drvdata = (struct gxp_i2c_drvdata *)_drvdata;
446 /* Check if the interrupt is for the current engine */
447 regmap_read(i2cg_map, GXP_I2CINTSTAT, &value);
448 if (!(value & BIT(drvdata->engine)))
451 value = readb(drvdata->base + GXP_I2CEVTERR);
454 if (value & ~(MASK_MASTER_EVENT | MASK_SLAVE_CMD_EVENT |
455 MASK_SLAVE_DATA_EVENT)) {
456 /* Clear all events */
457 writeb(0x00, drvdata->base + GXP_I2CEVTERR);
458 drvdata->state = GXP_I2C_ERROR;
459 gxp_i2c_stop(drvdata);
463 if (IS_ENABLED(CONFIG_I2C_SLAVE)) {
465 if (value & (MASK_SLAVE_CMD_EVENT | MASK_SLAVE_DATA_EVENT)) {
466 if (gxp_i2c_slave_irq_handler(drvdata))
473 switch (drvdata->state) {
474 case GXP_I2C_ADDR_PHASE:
475 gxp_i2c_chk_addr_ack(drvdata);
478 case GXP_I2C_RDATA_PHASE:
479 gxp_i2c_ack_data(drvdata);
482 case GXP_I2C_WDATA_PHASE:
483 gxp_i2c_chk_data_ack(drvdata);
490 static void gxp_i2c_init(struct gxp_i2c_drvdata *drvdata)
492 drvdata->state = GXP_I2C_IDLE;
493 writeb(2000000 / drvdata->t.bus_freq_hz,
494 drvdata->base + GXP_I2CFREQDIV);
495 writeb(FILTER_CNT | FAIRNESS_CNT,
496 drvdata->base + GXP_I2CFLTFAIR);
497 writeb(GXP_DATA_EDGE_RST_CTRL, drvdata->base + GXP_I2CTMOEDG);
498 writeb(0x00, drvdata->base + GXP_I2CCYCTIM);
499 writeb(0x00, drvdata->base + GXP_I2CSNPAA);
500 writeb(0x00, drvdata->base + GXP_I2CADVFEAT);
501 writeb(SNOOP_EVT_CLR | SLAVE_EVT_CLR | SNOOP_EVT_MASK |
502 SLAVE_EVT_MASK, drvdata->base + GXP_I2CSCMD);
503 writeb(MASTER_EVT_CLR, drvdata->base + GXP_I2CMCMD);
504 writeb(0x00, drvdata->base + GXP_I2CEVTERR);
505 writeb(0x00, drvdata->base + GXP_I2COWNADR);
508 static int gxp_i2c_probe(struct platform_device *pdev)
510 struct gxp_i2c_drvdata *drvdata;
512 struct i2c_adapter *adapter;
515 i2cg_map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
517 if (IS_ERR(i2cg_map)) {
518 return dev_err_probe(&pdev->dev, PTR_ERR(i2cg_map),
519 "failed to map i2cg_handle\n");
522 /* Disable interrupt */
523 regmap_update_bits(i2cg_map, GXP_I2CINTEN, 0x00000FFF, 0);
526 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata),
531 platform_set_drvdata(pdev, drvdata);
532 drvdata->dev = &pdev->dev;
533 init_completion(&drvdata->completion);
535 drvdata->base = devm_platform_ioremap_resource(pdev, 0);
536 if (IS_ERR(drvdata->base))
537 return PTR_ERR(drvdata->base);
539 /* Use physical memory address to determine which I2C engine this is. */
540 drvdata->engine = ((size_t)drvdata->base & 0xf00) >> 8;
542 if (drvdata->engine >= GXP_MAX_I2C_ENGINE) {
543 return dev_err_probe(&pdev->dev, -EINVAL, "i2c engine% is unsupported\n",
547 rc = platform_get_irq(pdev, 0);
552 rc = devm_request_irq(&pdev->dev, drvdata->irq, gxp_i2c_irq_handler,
553 IRQF_SHARED, gxp_i2c_name[drvdata->engine], drvdata);
555 return dev_err_probe(&pdev->dev, rc, "irq request failed\n");
557 i2c_parse_fw_timings(&pdev->dev, &drvdata->t, true);
559 gxp_i2c_init(drvdata);
561 /* Enable interrupt */
562 regmap_update_bits(i2cg_map, GXP_I2CINTEN, BIT(drvdata->engine),
563 BIT(drvdata->engine));
565 adapter = &drvdata->adapter;
566 i2c_set_adapdata(adapter, drvdata);
568 adapter->owner = THIS_MODULE;
569 strscpy(adapter->name, "HPE GXP I2C adapter", sizeof(adapter->name));
570 adapter->algo = &gxp_i2c_algo;
571 adapter->dev.parent = &pdev->dev;
572 adapter->dev.of_node = pdev->dev.of_node;
574 rc = i2c_add_adapter(adapter);
576 return dev_err_probe(&pdev->dev, rc, "i2c add adapter failed\n");
581 static void gxp_i2c_remove(struct platform_device *pdev)
583 struct gxp_i2c_drvdata *drvdata = platform_get_drvdata(pdev);
585 /* Disable interrupt */
586 regmap_update_bits(i2cg_map, GXP_I2CINTEN, BIT(drvdata->engine), 0);
587 i2c_del_adapter(&drvdata->adapter);
590 static const struct of_device_id gxp_i2c_of_match[] = {
591 { .compatible = "hpe,gxp-i2c" },
594 MODULE_DEVICE_TABLE(of, gxp_i2c_of_match);
596 static struct platform_driver gxp_i2c_driver = {
597 .probe = gxp_i2c_probe,
598 .remove_new = gxp_i2c_remove,
601 .of_match_table = gxp_i2c_of_match,
604 module_platform_driver(gxp_i2c_driver);
606 MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");
607 MODULE_DESCRIPTION("HPE GXP I2C bus driver");
608 MODULE_LICENSE("GPL");