1 /*
2  * X-Gene SLIMpro I2C Driver
3  *
4  * Copyright (c) 2014, Applied Micro Circuits Corporation
5  * Author: Feng Kan <fkan@apm.com>
6  * Author: Hieu Le <hnle@apm.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, see <http://www.gnu.org/licenses/>.
20  *
21  * This driver provides support for X-Gene SLIMpro I2C device access
22  * using the APM X-Gene SLIMpro mailbox driver.
23  *
24  */
25 #include <linux/acpi.h>
26 #include <linux/dma-mapping.h>
27 #include <linux/i2c.h>
28 #include <linux/interrupt.h>
29 #include <linux/mailbox_client.h>
30 #include <linux/module.h>
31 #include <linux/of.h>
32 #include <linux/platform_device.h>
33 #include <linux/version.h>
34 
35 #define MAILBOX_OP_TIMEOUT		1000	/* Operation time out in ms */
36 #define MAILBOX_I2C_INDEX		0
37 #define SLIMPRO_IIC_BUS			1	/* Use I2C bus 1 only */
38 
39 #define SMBUS_CMD_LEN			1
40 #define BYTE_DATA			1
41 #define WORD_DATA			2
42 #define BLOCK_DATA			3
43 
44 #define SLIMPRO_IIC_I2C_PROTOCOL	0
45 #define SLIMPRO_IIC_SMB_PROTOCOL	1
46 
47 #define SLIMPRO_IIC_READ		0
48 #define SLIMPRO_IIC_WRITE		1
49 
50 #define IIC_SMB_WITHOUT_DATA_LEN	0
51 #define IIC_SMB_WITH_DATA_LEN		1
52 
53 #define SLIMPRO_DEBUG_MSG		0
54 #define SLIMPRO_MSG_TYPE_SHIFT		28
55 #define SLIMPRO_DBG_SUBTYPE_I2C1READ	4
56 #define SLIMPRO_DBGMSG_TYPE_SHIFT	24
57 #define SLIMPRO_DBGMSG_TYPE_MASK	0x0F000000U
58 #define SLIMPRO_IIC_DEV_SHIFT		23
59 #define SLIMPRO_IIC_DEV_MASK		0x00800000U
60 #define SLIMPRO_IIC_DEVID_SHIFT		13
61 #define SLIMPRO_IIC_DEVID_MASK		0x007FE000U
62 #define SLIMPRO_IIC_RW_SHIFT		12
63 #define SLIMPRO_IIC_RW_MASK		0x00001000U
64 #define SLIMPRO_IIC_PROTO_SHIFT		11
65 #define SLIMPRO_IIC_PROTO_MASK		0x00000800U
66 #define SLIMPRO_IIC_ADDRLEN_SHIFT	8
67 #define SLIMPRO_IIC_ADDRLEN_MASK	0x00000700U
68 #define SLIMPRO_IIC_DATALEN_SHIFT	0
69 #define SLIMPRO_IIC_DATALEN_MASK	0x000000FFU
70 
71 /*
72  * SLIMpro I2C message encode
73  *
74  * dev		- Controller number (0-based)
75  * chip		- I2C chip address
76  * op		- SLIMPRO_IIC_READ or SLIMPRO_IIC_WRITE
77  * proto	- SLIMPRO_IIC_SMB_PROTOCOL or SLIMPRO_IIC_I2C_PROTOCOL
78  * addrlen	- Length of the address field
79  * datalen	- Length of the data field
80  */
81 #define SLIMPRO_IIC_ENCODE_MSG(dev, chip, op, proto, addrlen, datalen) \
82 	((SLIMPRO_DEBUG_MSG << SLIMPRO_MSG_TYPE_SHIFT) | \
83 	((SLIMPRO_DBG_SUBTYPE_I2C1READ << SLIMPRO_DBGMSG_TYPE_SHIFT) & \
84 	SLIMPRO_DBGMSG_TYPE_MASK) | \
85 	((dev << SLIMPRO_IIC_DEV_SHIFT) & SLIMPRO_IIC_DEV_MASK) | \
86 	((chip << SLIMPRO_IIC_DEVID_SHIFT) & SLIMPRO_IIC_DEVID_MASK) | \
87 	((op << SLIMPRO_IIC_RW_SHIFT) & SLIMPRO_IIC_RW_MASK) | \
88 	((proto << SLIMPRO_IIC_PROTO_SHIFT) & SLIMPRO_IIC_PROTO_MASK) | \
89 	((addrlen << SLIMPRO_IIC_ADDRLEN_SHIFT) & SLIMPRO_IIC_ADDRLEN_MASK) | \
90 	((datalen << SLIMPRO_IIC_DATALEN_SHIFT) & SLIMPRO_IIC_DATALEN_MASK))
91 
92 /*
93  * Encode for upper address for block data
94  */
95 #define SLIMPRO_IIC_ENCODE_FLAG_BUFADDR			0x80000000
96 #define SLIMPRO_IIC_ENCODE_FLAG_WITH_DATA_LEN(a)	((u32) (((a) << 30) \
97 								& 0x40000000))
98 #define SLIMPRO_IIC_ENCODE_UPPER_BUFADDR(a)		((u32) (((a) >> 12) \
99 								& 0x3FF00000))
100 #define SLIMPRO_IIC_ENCODE_ADDR(a)			((a) & 0x000FFFFF)
101 
102 struct slimpro_i2c_dev {
103 	struct i2c_adapter adapter;
104 	struct device *dev;
105 	struct mbox_chan *mbox_chan;
106 	struct mbox_client mbox_client;
107 	struct completion rd_complete;
108 	u8 dma_buffer[I2C_SMBUS_BLOCK_MAX];
109 	u32 *resp_msg;
110 };
111 
112 #define to_slimpro_i2c_dev(cl)	\
113 		container_of(cl, struct slimpro_i2c_dev, mbox_client)
114 
115 static void slimpro_i2c_rx_cb(struct mbox_client *cl, void *mssg)
116 {
117 	struct slimpro_i2c_dev *ctx = to_slimpro_i2c_dev(cl);
118 
119 	/*
120 	 * Response message format:
121 	 * mssg[0] is the return code of the operation
122 	 * mssg[1] is the first data word
123 	 * mssg[2] is NOT used
124 	 */
125 	if (ctx->resp_msg)
126 		*ctx->resp_msg = ((u32 *)mssg)[1];
127 
128 	if (ctx->mbox_client.tx_block)
129 		complete(&ctx->rd_complete);
130 }
131 
132 static int start_i2c_msg_xfer(struct slimpro_i2c_dev *ctx)
133 {
134 	if (ctx->mbox_client.tx_block) {
135 		if (!wait_for_completion_timeout(&ctx->rd_complete,
136 						 msecs_to_jiffies(MAILBOX_OP_TIMEOUT)))
137 			return -ETIMEDOUT;
138 	}
139 
140 	/* Check of invalid data or no device */
141 	if (*ctx->resp_msg == 0xffffffff)
142 		return -ENODEV;
143 
144 	return 0;
145 }
146 
147 static int slimpro_i2c_rd(struct slimpro_i2c_dev *ctx, u32 chip,
148 			  u32 addr, u32 addrlen, u32 protocol,
149 			  u32 readlen, u32 *data)
150 {
151 	u32 msg[3];
152 	int rc;
153 
154 	msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip,
155 					SLIMPRO_IIC_READ, protocol, addrlen, readlen);
156 	msg[1] = SLIMPRO_IIC_ENCODE_ADDR(addr);
157 	msg[2] = 0;
158 	ctx->resp_msg = data;
159 	rc = mbox_send_message(ctx->mbox_chan, &msg);
160 	if (rc < 0)
161 		goto err;
162 
163 	rc = start_i2c_msg_xfer(ctx);
164 err:
165 	ctx->resp_msg = NULL;
166 	return rc;
167 }
168 
169 static int slimpro_i2c_wr(struct slimpro_i2c_dev *ctx, u32 chip,
170 			  u32 addr, u32 addrlen, u32 protocol, u32 writelen,
171 			  u32 data)
172 {
173 	u32 msg[3];
174 	int rc;
175 
176 	msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip,
177 					SLIMPRO_IIC_WRITE, protocol, addrlen, writelen);
178 	msg[1] = SLIMPRO_IIC_ENCODE_ADDR(addr);
179 	msg[2] = data;
180 	ctx->resp_msg = msg;
181 
182 	rc = mbox_send_message(ctx->mbox_chan, &msg);
183 	if (rc < 0)
184 		goto err;
185 
186 	rc = start_i2c_msg_xfer(ctx);
187 err:
188 	ctx->resp_msg = NULL;
189 	return rc;
190 }
191 
192 static int slimpro_i2c_blkrd(struct slimpro_i2c_dev *ctx, u32 chip, u32 addr,
193 			     u32 addrlen, u32 protocol, u32 readlen,
194 			     u32 with_data_len, void *data)
195 {
196 	dma_addr_t paddr;
197 	u32 msg[3];
198 	int rc;
199 
200 	paddr = dma_map_single(ctx->dev, ctx->dma_buffer, readlen, DMA_FROM_DEVICE);
201 	if (dma_mapping_error(ctx->dev, paddr)) {
202 		dev_err(&ctx->adapter.dev, "Error in mapping dma buffer %p\n",
203 			ctx->dma_buffer);
204 		rc = -ENOMEM;
205 		goto err;
206 	}
207 
208 	msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip, SLIMPRO_IIC_READ,
209 					protocol, addrlen, readlen);
210 	msg[1] = SLIMPRO_IIC_ENCODE_FLAG_BUFADDR |
211 		 SLIMPRO_IIC_ENCODE_FLAG_WITH_DATA_LEN(with_data_len) |
212 		 SLIMPRO_IIC_ENCODE_UPPER_BUFADDR(paddr) |
213 		 SLIMPRO_IIC_ENCODE_ADDR(addr);
214 	msg[2] = (u32)paddr;
215 	ctx->resp_msg = msg;
216 
217 	rc = mbox_send_message(ctx->mbox_chan, &msg);
218 	if (rc < 0)
219 		goto err_unmap;
220 
221 	rc = start_i2c_msg_xfer(ctx);
222 
223 	/* Copy to destination */
224 	memcpy(data, ctx->dma_buffer, readlen);
225 
226 err_unmap:
227 	dma_unmap_single(ctx->dev, paddr, readlen, DMA_FROM_DEVICE);
228 err:
229 	ctx->resp_msg = NULL;
230 	return rc;
231 }
232 
233 static int slimpro_i2c_blkwr(struct slimpro_i2c_dev *ctx, u32 chip,
234 			     u32 addr, u32 addrlen, u32 protocol, u32 writelen,
235 			     void *data)
236 {
237 	dma_addr_t paddr;
238 	u32 msg[3];
239 	int rc;
240 
241 	memcpy(ctx->dma_buffer, data, writelen);
242 	paddr = dma_map_single(ctx->dev, ctx->dma_buffer, writelen,
243 			       DMA_TO_DEVICE);
244 	if (dma_mapping_error(ctx->dev, paddr)) {
245 		dev_err(&ctx->adapter.dev, "Error in mapping dma buffer %p\n",
246 			ctx->dma_buffer);
247 		rc = -ENOMEM;
248 		goto err;
249 	}
250 
251 	msg[0] = SLIMPRO_IIC_ENCODE_MSG(SLIMPRO_IIC_BUS, chip, SLIMPRO_IIC_WRITE,
252 					protocol, addrlen, writelen);
253 	msg[1] = SLIMPRO_IIC_ENCODE_FLAG_BUFADDR |
254 		 SLIMPRO_IIC_ENCODE_UPPER_BUFADDR(paddr) |
255 		 SLIMPRO_IIC_ENCODE_ADDR(addr);
256 	msg[2] = (u32)paddr;
257 	ctx->resp_msg = msg;
258 
259 	if (ctx->mbox_client.tx_block)
260 		reinit_completion(&ctx->rd_complete);
261 
262 	rc = mbox_send_message(ctx->mbox_chan, &msg);
263 	if (rc < 0)
264 		goto err_unmap;
265 
266 	rc = start_i2c_msg_xfer(ctx);
267 
268 err_unmap:
269 	dma_unmap_single(ctx->dev, paddr, writelen, DMA_TO_DEVICE);
270 err:
271 	ctx->resp_msg = NULL;
272 	return rc;
273 }
274 
275 static int xgene_slimpro_i2c_xfer(struct i2c_adapter *adap, u16 addr,
276 				  unsigned short flags, char read_write,
277 				  u8 command, int size,
278 				  union i2c_smbus_data *data)
279 {
280 	struct slimpro_i2c_dev *ctx = i2c_get_adapdata(adap);
281 	int ret = -EOPNOTSUPP;
282 	u32 val;
283 
284 	switch (size) {
285 	case I2C_SMBUS_BYTE:
286 		if (read_write == I2C_SMBUS_READ) {
287 			ret = slimpro_i2c_rd(ctx, addr, 0, 0,
288 					     SLIMPRO_IIC_SMB_PROTOCOL,
289 					     BYTE_DATA, &val);
290 			data->byte = val;
291 		} else {
292 			ret = slimpro_i2c_wr(ctx, addr, command, SMBUS_CMD_LEN,
293 					     SLIMPRO_IIC_SMB_PROTOCOL,
294 					     0, 0);
295 		}
296 		break;
297 	case I2C_SMBUS_BYTE_DATA:
298 		if (read_write == I2C_SMBUS_READ) {
299 			ret = slimpro_i2c_rd(ctx, addr, command, SMBUS_CMD_LEN,
300 					     SLIMPRO_IIC_SMB_PROTOCOL,
301 					     BYTE_DATA, &val);
302 			data->byte = val;
303 		} else {
304 			val = data->byte;
305 			ret = slimpro_i2c_wr(ctx, addr, command, SMBUS_CMD_LEN,
306 					     SLIMPRO_IIC_SMB_PROTOCOL,
307 					     BYTE_DATA, val);
308 		}
309 		break;
310 	case I2C_SMBUS_WORD_DATA:
311 		if (read_write == I2C_SMBUS_READ) {
312 			ret = slimpro_i2c_rd(ctx, addr, command, SMBUS_CMD_LEN,
313 					     SLIMPRO_IIC_SMB_PROTOCOL,
314 					     WORD_DATA, &val);
315 			data->word = val;
316 		} else {
317 			val = data->word;
318 			ret = slimpro_i2c_wr(ctx, addr, command, SMBUS_CMD_LEN,
319 					     SLIMPRO_IIC_SMB_PROTOCOL,
320 					     WORD_DATA, val);
321 		}
322 		break;
323 	case I2C_SMBUS_BLOCK_DATA:
324 		if (read_write == I2C_SMBUS_READ) {
325 			ret = slimpro_i2c_blkrd(ctx, addr, command,
326 						SMBUS_CMD_LEN,
327 						SLIMPRO_IIC_SMB_PROTOCOL,
328 						I2C_SMBUS_BLOCK_MAX + 1,
329 						IIC_SMB_WITH_DATA_LEN,
330 						&data->block[0]);
331 
332 		} else {
333 			ret = slimpro_i2c_blkwr(ctx, addr, command,
334 						SMBUS_CMD_LEN,
335 						SLIMPRO_IIC_SMB_PROTOCOL,
336 						data->block[0] + 1,
337 						&data->block[0]);
338 		}
339 		break;
340 	case I2C_SMBUS_I2C_BLOCK_DATA:
341 		if (read_write == I2C_SMBUS_READ) {
342 			ret = slimpro_i2c_blkrd(ctx, addr,
343 						command,
344 						SMBUS_CMD_LEN,
345 						SLIMPRO_IIC_I2C_PROTOCOL,
346 						I2C_SMBUS_BLOCK_MAX,
347 						IIC_SMB_WITHOUT_DATA_LEN,
348 						&data->block[1]);
349 		} else {
350 			ret = slimpro_i2c_blkwr(ctx, addr, command,
351 						SMBUS_CMD_LEN,
352 						SLIMPRO_IIC_I2C_PROTOCOL,
353 						data->block[0],
354 						&data->block[1]);
355 		}
356 		break;
357 	default:
358 		break;
359 	}
360 	return ret;
361 }
362 
363 /*
364 * Return list of supported functionality.
365 */
366 static u32 xgene_slimpro_i2c_func(struct i2c_adapter *adapter)
367 {
368 	return I2C_FUNC_SMBUS_BYTE |
369 		I2C_FUNC_SMBUS_BYTE_DATA |
370 		I2C_FUNC_SMBUS_WORD_DATA |
371 		I2C_FUNC_SMBUS_BLOCK_DATA |
372 		I2C_FUNC_SMBUS_I2C_BLOCK;
373 }
374 
375 static struct i2c_algorithm xgene_slimpro_i2c_algorithm = {
376 	.smbus_xfer = xgene_slimpro_i2c_xfer,
377 	.functionality = xgene_slimpro_i2c_func,
378 };
379 
380 static int xgene_slimpro_i2c_probe(struct platform_device *pdev)
381 {
382 	struct slimpro_i2c_dev *ctx;
383 	struct i2c_adapter *adapter;
384 	struct mbox_client *cl;
385 	int rc;
386 
387 	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
388 	if (!ctx)
389 		return -ENOMEM;
390 
391 	ctx->dev = &pdev->dev;
392 	platform_set_drvdata(pdev, ctx);
393 	cl = &ctx->mbox_client;
394 
395 	/* Request mailbox channel */
396 	cl->dev = &pdev->dev;
397 	cl->rx_callback = slimpro_i2c_rx_cb;
398 	cl->tx_block = true;
399 	init_completion(&ctx->rd_complete);
400 	cl->tx_tout = MAILBOX_OP_TIMEOUT;
401 	cl->knows_txdone = false;
402 	ctx->mbox_chan = mbox_request_channel(cl, MAILBOX_I2C_INDEX);
403 	if (IS_ERR(ctx->mbox_chan)) {
404 		dev_err(&pdev->dev, "i2c mailbox channel request failed\n");
405 		return PTR_ERR(ctx->mbox_chan);
406 	}
407 
408 	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
409 	if (rc)
410 		dev_warn(&pdev->dev, "Unable to set dma mask\n");
411 
412 	/* Setup I2C adapter */
413 	adapter = &ctx->adapter;
414 	snprintf(adapter->name, sizeof(adapter->name), "MAILBOX I2C");
415 	adapter->algo = &xgene_slimpro_i2c_algorithm;
416 	adapter->class = I2C_CLASS_HWMON;
417 	adapter->dev.parent = &pdev->dev;
418 	i2c_set_adapdata(adapter, ctx);
419 	rc = i2c_add_adapter(adapter);
420 	if (rc) {
421 		dev_err(&pdev->dev, "Adapter registeration failed\n");
422 		mbox_free_channel(ctx->mbox_chan);
423 		return rc;
424 	}
425 
426 	dev_info(&pdev->dev, "Mailbox I2C Adapter registered\n");
427 	return 0;
428 }
429 
430 static int xgene_slimpro_i2c_remove(struct platform_device *pdev)
431 {
432 	struct slimpro_i2c_dev *ctx = platform_get_drvdata(pdev);
433 
434 	i2c_del_adapter(&ctx->adapter);
435 
436 	mbox_free_channel(ctx->mbox_chan);
437 
438 	return 0;
439 }
440 
441 static const struct of_device_id xgene_slimpro_i2c_dt_ids[] = {
442 	{.compatible = "apm,xgene-slimpro-i2c" },
443 	{},
444 };
445 MODULE_DEVICE_TABLE(of, xgene_slimpro_i2c_dt_ids);
446 
447 #ifdef CONFIG_ACPI
448 static const struct acpi_device_id xgene_slimpro_i2c_acpi_ids[] = {
449 	{"APMC0D40", 0},
450 	{}
451 };
452 MODULE_DEVICE_TABLE(acpi, xgene_slimpro_i2c_acpi_ids);
453 #endif
454 
455 static struct platform_driver xgene_slimpro_i2c_driver = {
456 	.probe	= xgene_slimpro_i2c_probe,
457 	.remove	= xgene_slimpro_i2c_remove,
458 	.driver	= {
459 		.name	= "xgene-slimpro-i2c",
460 		.of_match_table = of_match_ptr(xgene_slimpro_i2c_dt_ids),
461 		.acpi_match_table = ACPI_PTR(xgene_slimpro_i2c_acpi_ids)
462 	},
463 };
464 
465 module_platform_driver(xgene_slimpro_i2c_driver);
466 
467 MODULE_DESCRIPTION("APM X-Gene SLIMpro I2C driver");
468 MODULE_AUTHOR("Feng Kan <fkan@apm.com>");
469 MODULE_AUTHOR("Hieu Le <hnle@apm.com>");
470 MODULE_LICENSE("GPL");
471