1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
5 * Copyright (C) 2016-2020 Mellanox Technologies
8 #include <linux/delay.h>
10 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/platform_data/mlxreg.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
19 #define MLXPLAT_CPLD_LPC_I2C_BASE_ADDR 0x2000
20 #define MLXCPLD_I2C_DEVICE_NAME "i2c_mlxcpld"
21 #define MLXCPLD_I2C_VALID_FLAG (I2C_M_RECV_LEN | I2C_M_RD)
22 #define MLXCPLD_I2C_BUS_NUM 1
23 #define MLXCPLD_I2C_DATA_REG_SZ 36
24 #define MLXCPLD_I2C_DATA_SZ_BIT BIT(5)
25 #define MLXCPLD_I2C_DATA_SZ_MASK GENMASK(6, 5)
26 #define MLXCPLD_I2C_SMBUS_BLK_BIT BIT(7)
27 #define MLXCPLD_I2C_MAX_ADDR_LEN 4
28 #define MLXCPLD_I2C_RETR_NUM 2
29 #define MLXCPLD_I2C_XFER_TO 500000 /* usec */
30 #define MLXCPLD_I2C_POLL_TIME 400 /* usec */
32 /* LPC I2C registers */
33 #define MLXCPLD_LPCI2C_CPBLTY_REG 0x0
34 #define MLXCPLD_LPCI2C_CTRL_REG 0x1
35 #define MLXCPLD_LPCI2C_HALF_CYC_REG 0x4
36 #define MLXCPLD_LPCI2C_I2C_HOLD_REG 0x5
37 #define MLXCPLD_LPCI2C_CMD_REG 0x6
38 #define MLXCPLD_LPCI2C_NUM_DAT_REG 0x7
39 #define MLXCPLD_LPCI2C_NUM_ADDR_REG 0x8
40 #define MLXCPLD_LPCI2C_STATUS_REG 0x9
41 #define MLXCPLD_LPCI2C_DATA_REG 0xa
43 /* LPC I2C masks and parametres */
44 #define MLXCPLD_LPCI2C_RST_SEL_MASK 0x1
45 #define MLXCPLD_LPCI2C_TRANS_END 0x1
46 #define MLXCPLD_LPCI2C_STATUS_NACK 0x10
47 #define MLXCPLD_LPCI2C_NO_IND 0
48 #define MLXCPLD_LPCI2C_ACK_IND 1
49 #define MLXCPLD_LPCI2C_NACK_IND 2
51 #define MLXCPLD_I2C_FREQ_1000KHZ_SET 0x04
52 #define MLXCPLD_I2C_FREQ_400KHZ_SET 0x0c
53 #define MLXCPLD_I2C_FREQ_100KHZ_SET 0x42
55 enum mlxcpld_i2c_frequency {
56 MLXCPLD_I2C_FREQ_1000KHZ = 1,
57 MLXCPLD_I2C_FREQ_400KHZ = 2,
58 MLXCPLD_I2C_FREQ_100KHZ = 3,
61 struct mlxcpld_i2c_curr_xfer {
69 struct mlxcpld_i2c_priv {
70 struct i2c_adapter adap;
73 struct mlxcpld_i2c_curr_xfer xfer;
78 static void mlxcpld_i2c_lpc_write_buf(u8 *data, u8 len, u32 addr)
82 for (i = 0; i < len - len % 4; i += 4)
83 outl(*(u32 *)(data + i), addr + i);
85 outb(*(data + i), addr + i);
88 static void mlxcpld_i2c_lpc_read_buf(u8 *data, u8 len, u32 addr)
92 for (i = 0; i < len - len % 4; i += 4)
93 *(u32 *)(data + i) = inl(addr + i);
95 *(data + i) = inb(addr + i);
98 static void mlxcpld_i2c_read_comm(struct mlxcpld_i2c_priv *priv, u8 offs,
101 u32 addr = priv->base_addr + offs;
108 *((u16 *)data) = inw(addr);
111 *((u16 *)data) = inw(addr);
112 *(data + 2) = inb(addr + 2);
115 *((u32 *)data) = inl(addr);
118 mlxcpld_i2c_lpc_read_buf(data, datalen, addr);
123 static void mlxcpld_i2c_write_comm(struct mlxcpld_i2c_priv *priv, u8 offs,
124 u8 *data, u8 datalen)
126 u32 addr = priv->base_addr + offs;
133 outw(*((u16 *)data), addr);
136 outw(*((u16 *)data), addr);
137 outb(*(data + 2), addr + 2);
140 outl(*((u32 *)data), addr);
143 mlxcpld_i2c_lpc_write_buf(data, datalen, addr);
149 * Check validity of received i2c messages parameters.
150 * Returns 0 if OK, other - in case of invalid parameters.
152 static int mlxcpld_i2c_check_msg_params(struct mlxcpld_i2c_priv *priv,
153 struct i2c_msg *msgs, int num)
158 dev_err(priv->dev, "Incorrect 0 num of messages\n");
162 if (unlikely(msgs[0].addr > 0x7f)) {
163 dev_err(priv->dev, "Invalid address 0x%03x\n",
168 for (i = 0; i < num; ++i) {
169 if (unlikely(!msgs[i].buf)) {
170 dev_err(priv->dev, "Invalid buf in msg[%d]\n",
174 if (unlikely(msgs[0].addr != msgs[i].addr)) {
175 dev_err(priv->dev, "Invalid addr in msg[%d]\n",
185 * Check if transfer is completed and status of operation.
186 * Returns 0 - transfer completed (both ACK or NACK),
187 * negative - transfer isn't finished.
189 static int mlxcpld_i2c_check_status(struct mlxcpld_i2c_priv *priv, int *status)
193 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1);
195 if (val & MLXCPLD_LPCI2C_TRANS_END) {
196 if (val & MLXCPLD_LPCI2C_STATUS_NACK)
198 * The slave is unable to accept the data. No such
199 * slave, command not understood, or unable to accept
202 *status = MLXCPLD_LPCI2C_NACK_IND;
204 *status = MLXCPLD_LPCI2C_ACK_IND;
207 *status = MLXCPLD_LPCI2C_NO_IND;
212 static void mlxcpld_i2c_set_transf_data(struct mlxcpld_i2c_priv *priv,
213 struct i2c_msg *msgs, int num,
216 priv->xfer.msg = msgs;
217 priv->xfer.msg_num = num;
220 * All upper layers currently are never use transfer with more than
221 * 2 messages. Actually, it's also not so relevant in Mellanox systems
222 * because of HW limitation. Max size of transfer is not more than 32
223 * or 68 bytes in the current x86 LPCI2C bridge.
225 priv->xfer.cmd = msgs[num - 1].flags & I2C_M_RD;
227 if (priv->xfer.cmd == I2C_M_RD && comm_len != msgs[0].len) {
228 priv->xfer.addr_width = msgs[0].len;
229 priv->xfer.data_len = comm_len - priv->xfer.addr_width;
231 priv->xfer.addr_width = 0;
232 priv->xfer.data_len = comm_len;
236 /* Reset CPLD LPCI2C block */
237 static void mlxcpld_i2c_reset(struct mlxcpld_i2c_priv *priv)
241 mutex_lock(&priv->lock);
243 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1);
244 val &= ~MLXCPLD_LPCI2C_RST_SEL_MASK;
245 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1);
247 mutex_unlock(&priv->lock);
250 /* Make sure the CPLD is ready to start transmitting. */
251 static int mlxcpld_i2c_check_busy(struct mlxcpld_i2c_priv *priv)
255 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1);
257 if (val & MLXCPLD_LPCI2C_TRANS_END)
263 static int mlxcpld_i2c_wait_for_free(struct mlxcpld_i2c_priv *priv)
268 if (!mlxcpld_i2c_check_busy(priv))
270 usleep_range(MLXCPLD_I2C_POLL_TIME / 2, MLXCPLD_I2C_POLL_TIME);
271 timeout += MLXCPLD_I2C_POLL_TIME;
272 } while (timeout <= MLXCPLD_I2C_XFER_TO);
274 if (timeout > MLXCPLD_I2C_XFER_TO)
281 * Wait for master transfer to complete.
282 * It puts current process to sleep until we get interrupt or timeout expires.
283 * Returns the number of transferred or read bytes or error (<0).
285 static int mlxcpld_i2c_wait_for_tc(struct mlxcpld_i2c_priv *priv)
287 int status, i, timeout = 0;
291 usleep_range(MLXCPLD_I2C_POLL_TIME / 2, MLXCPLD_I2C_POLL_TIME);
292 if (!mlxcpld_i2c_check_status(priv, &status))
294 timeout += MLXCPLD_I2C_POLL_TIME;
295 } while (status == 0 && timeout < MLXCPLD_I2C_XFER_TO);
298 case MLXCPLD_LPCI2C_NO_IND:
301 case MLXCPLD_LPCI2C_ACK_IND:
302 if (priv->xfer.cmd != I2C_M_RD)
303 return (priv->xfer.addr_width + priv->xfer.data_len);
305 if (priv->xfer.msg_num == 1)
310 if (!priv->xfer.msg[i].buf)
314 * Actual read data len will be always the same as
315 * requested len. 0xff (line pull-up) will be returned
316 * if slave has no data to return. Thus don't read
317 * MLXCPLD_LPCI2C_NUM_DAT_REG reg from CPLD. Only in case of
318 * SMBus block read transaction data len can be different,
321 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_NUM_ADDR_REG, &val,
323 if (priv->smbus_block && (val & MLXCPLD_I2C_SMBUS_BLK_BIT)) {
324 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_NUM_DAT_REG,
326 if (unlikely(datalen > I2C_SMBUS_BLOCK_MAX)) {
327 dev_err(priv->dev, "Incorrect smbus block read message len\n");
331 datalen = priv->xfer.data_len;
334 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_DATA_REG,
335 priv->xfer.msg[i].buf, datalen);
339 case MLXCPLD_LPCI2C_NACK_IND:
347 static void mlxcpld_i2c_xfer_msg(struct mlxcpld_i2c_priv *priv)
352 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_DAT_REG,
353 &priv->xfer.data_len, 1);
355 val = priv->xfer.addr_width;
356 /* Notify HW about SMBus block read transaction */
357 if (priv->smbus_block && priv->xfer.msg_num >= 2 &&
358 priv->xfer.msg[1].len == 1 &&
359 (priv->xfer.msg[1].flags & I2C_M_RECV_LEN) &&
360 (priv->xfer.msg[1].flags & I2C_M_RD))
361 val |= MLXCPLD_I2C_SMBUS_BLK_BIT;
363 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_ADDR_REG, &val, 1);
365 for (i = 0; i < priv->xfer.msg_num; i++) {
366 if ((priv->xfer.msg[i].flags & I2C_M_RD) != I2C_M_RD) {
367 /* Don't write to CPLD buffer in read transaction */
368 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_DATA_REG +
369 len, priv->xfer.msg[i].buf,
370 priv->xfer.msg[i].len);
371 len += priv->xfer.msg[i].len;
376 * Set target slave address with command for master transfer.
377 * It should be latest executed function before CPLD transaction.
379 cmd = (priv->xfer.msg[0].addr << 1) | priv->xfer.cmd;
380 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CMD_REG, &cmd, 1);
384 * Generic lpc-i2c transfer.
385 * Returns the number of processed messages or error (<0).
387 static int mlxcpld_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
390 struct mlxcpld_i2c_priv *priv = i2c_get_adapdata(adap);
394 err = mlxcpld_i2c_check_msg_params(priv, msgs, num);
396 dev_err(priv->dev, "Incorrect message\n");
400 for (i = 0; i < num; ++i)
401 comm_len += msgs[i].len;
403 /* Check bus state */
404 if (mlxcpld_i2c_wait_for_free(priv)) {
405 dev_err(priv->dev, "LPCI2C bridge is busy\n");
408 * Usually it means something serious has happened.
409 * We can not have unfinished previous transfer
410 * so it doesn't make any sense to try to stop it.
411 * Probably we were not able to recover from the
413 * The only reasonable thing - is soft reset.
415 mlxcpld_i2c_reset(priv);
416 if (mlxcpld_i2c_check_busy(priv)) {
417 dev_err(priv->dev, "LPCI2C bridge is busy after reset\n");
422 mlxcpld_i2c_set_transf_data(priv, msgs, num, comm_len);
424 mutex_lock(&priv->lock);
426 /* Do real transfer. Can't fail */
427 mlxcpld_i2c_xfer_msg(priv);
429 /* Wait for transaction complete */
430 err = mlxcpld_i2c_wait_for_tc(priv);
432 mutex_unlock(&priv->lock);
434 return err < 0 ? err : num;
437 static u32 mlxcpld_i2c_func(struct i2c_adapter *adap)
439 struct mlxcpld_i2c_priv *priv = i2c_get_adapdata(adap);
441 if (priv->smbus_block)
442 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
443 I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_BLOCK_DATA;
445 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
446 I2C_FUNC_SMBUS_I2C_BLOCK;
449 static const struct i2c_algorithm mlxcpld_i2c_algo = {
450 .master_xfer = mlxcpld_i2c_xfer,
451 .functionality = mlxcpld_i2c_func
454 static const struct i2c_adapter_quirks mlxcpld_i2c_quirks = {
455 .flags = I2C_AQ_COMB_WRITE_THEN_READ,
456 .max_read_len = MLXCPLD_I2C_DATA_REG_SZ - MLXCPLD_I2C_MAX_ADDR_LEN,
457 .max_write_len = MLXCPLD_I2C_DATA_REG_SZ,
458 .max_comb_1st_msg_len = 4,
461 static const struct i2c_adapter_quirks mlxcpld_i2c_quirks_ext = {
462 .flags = I2C_AQ_COMB_WRITE_THEN_READ,
463 .max_read_len = MLXCPLD_I2C_DATA_REG_SZ * 2 - MLXCPLD_I2C_MAX_ADDR_LEN,
464 .max_write_len = MLXCPLD_I2C_DATA_REG_SZ * 2,
465 .max_comb_1st_msg_len = 4,
468 static struct i2c_adapter mlxcpld_i2c_adapter = {
469 .owner = THIS_MODULE,
470 .name = "i2c-mlxcpld",
471 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
472 .algo = &mlxcpld_i2c_algo,
473 .quirks = &mlxcpld_i2c_quirks,
474 .retries = MLXCPLD_I2C_RETR_NUM,
475 .nr = MLXCPLD_I2C_BUS_NUM,
479 mlxcpld_i2c_set_frequency(struct mlxcpld_i2c_priv *priv,
480 struct mlxreg_core_hotplug_platform_data *pdata)
482 struct mlxreg_core_item *item = pdata->items;
483 struct mlxreg_core_data *data;
491 /* Read frequency setting. */
493 err = regmap_read(pdata->regmap, data->reg, ®val);
497 /* Set frequency only if it is not 100KHz, which is default. */
498 switch ((regval & data->mask) >> data->bit) {
499 case MLXCPLD_I2C_FREQ_1000KHZ:
500 freq = MLXCPLD_I2C_FREQ_1000KHZ_SET;
502 case MLXCPLD_I2C_FREQ_400KHZ:
503 freq = MLXCPLD_I2C_FREQ_400KHZ_SET;
509 mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_HALF_CYC_REG, &freq, 1);
514 static int mlxcpld_i2c_probe(struct platform_device *pdev)
516 struct mlxreg_core_hotplug_platform_data *pdata;
517 struct mlxcpld_i2c_priv *priv;
521 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
525 mutex_init(&priv->lock);
526 platform_set_drvdata(pdev, priv);
528 priv->dev = &pdev->dev;
529 priv->base_addr = MLXPLAT_CPLD_LPC_I2C_BASE_ADDR;
531 /* Set I2C bus frequency if platform data provides this info. */
532 pdata = dev_get_platdata(&pdev->dev);
534 err = mlxcpld_i2c_set_frequency(priv, pdata);
536 goto mlxcpld_i2_probe_failed;
539 /* Register with i2c layer */
540 mlxcpld_i2c_adapter.timeout = usecs_to_jiffies(MLXCPLD_I2C_XFER_TO);
541 /* Read capability register */
542 mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_CPBLTY_REG, &val, 1);
543 /* Check support for extended transaction length */
544 if ((val & MLXCPLD_I2C_DATA_SZ_MASK) == MLXCPLD_I2C_DATA_SZ_BIT)
545 mlxcpld_i2c_adapter.quirks = &mlxcpld_i2c_quirks_ext;
546 /* Check support for smbus block transaction */
547 if (val & MLXCPLD_I2C_SMBUS_BLK_BIT)
548 priv->smbus_block = true;
550 mlxcpld_i2c_adapter.nr = pdev->id;
551 priv->adap = mlxcpld_i2c_adapter;
552 priv->adap.dev.parent = &pdev->dev;
553 i2c_set_adapdata(&priv->adap, priv);
555 err = i2c_add_numbered_adapter(&priv->adap);
557 goto mlxcpld_i2_probe_failed;
561 mlxcpld_i2_probe_failed:
562 mutex_destroy(&priv->lock);
566 static int mlxcpld_i2c_remove(struct platform_device *pdev)
568 struct mlxcpld_i2c_priv *priv = platform_get_drvdata(pdev);
570 i2c_del_adapter(&priv->adap);
571 mutex_destroy(&priv->lock);
576 static struct platform_driver mlxcpld_i2c_driver = {
577 .probe = mlxcpld_i2c_probe,
578 .remove = mlxcpld_i2c_remove,
580 .name = MLXCPLD_I2C_DEVICE_NAME,
584 module_platform_driver(mlxcpld_i2c_driver);
586 MODULE_AUTHOR("Michael Shych <michaels@mellanox.com>");
587 MODULE_DESCRIPTION("Mellanox I2C-CPLD controller driver");
588 MODULE_LICENSE("Dual BSD/GPL");
589 MODULE_ALIAS("platform:i2c-mlxcpld");