1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Nano River Technologies viperboard i2c controller driver
4 *
5 * (C) 2012 by Lemonage GmbH
6 * Author: Lars Poeschel <poeschel@lemonage.de>
7 * All rights reserved.
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/errno.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/string_choices.h>
15 #include <linux/types.h>
16 #include <linux/mutex.h>
17 #include <linux/platform_device.h>
18
19 #include <linux/usb.h>
20 #include <linux/i2c.h>
21
22 #include <linux/mfd/viperboard.h>
23
24 struct vprbrd_i2c {
25 struct i2c_adapter i2c;
26 u8 bus_freq_param;
27 };
28
29 /* i2c bus frequency module parameter */
30 static u8 i2c_bus_param;
31 static unsigned int i2c_bus_freq = 100;
32 module_param(i2c_bus_freq, int, 0);
33 MODULE_PARM_DESC(i2c_bus_freq,
34 "i2c bus frequency in khz (default is 100) valid values: 10, 100, 200, 400, 1000, 3000, 6000");
35
vprbrd_i2c_status(struct i2c_adapter * i2c,struct vprbrd_i2c_status * status,bool prev_error)36 static int vprbrd_i2c_status(struct i2c_adapter *i2c,
37 struct vprbrd_i2c_status *status, bool prev_error)
38 {
39 u16 bytes_xfer;
40 int ret;
41 struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
42
43 /* check for protocol error */
44 bytes_xfer = sizeof(struct vprbrd_i2c_status);
45
46 ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
47 VPRBRD_USB_REQUEST_I2C, VPRBRD_USB_TYPE_IN, 0x0000, 0x0000,
48 status, bytes_xfer, VPRBRD_USB_TIMEOUT_MS);
49
50 if (ret != bytes_xfer)
51 prev_error = true;
52
53 if (prev_error) {
54 dev_err(&i2c->dev, "failure in usb communication\n");
55 return -EREMOTEIO;
56 }
57
58 dev_dbg(&i2c->dev, " status = %d\n", status->status);
59 if (status->status != 0x00) {
60 dev_err(&i2c->dev, "failure: i2c protocol error\n");
61 return -EPROTO;
62 }
63 return 0;
64 }
65
vprbrd_i2c_receive(struct usb_device * usb_dev,struct vprbrd_i2c_read_msg * rmsg,int bytes_xfer)66 static int vprbrd_i2c_receive(struct usb_device *usb_dev,
67 struct vprbrd_i2c_read_msg *rmsg, int bytes_xfer)
68 {
69 int ret, bytes_actual;
70 int error = 0;
71
72 /* send the read request */
73 ret = usb_bulk_msg(usb_dev,
74 usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), rmsg,
75 sizeof(struct vprbrd_i2c_read_hdr), &bytes_actual,
76 VPRBRD_USB_TIMEOUT_MS);
77
78 if ((ret < 0)
79 || (bytes_actual != sizeof(struct vprbrd_i2c_read_hdr))) {
80 dev_err(&usb_dev->dev, "failure transmitting usb\n");
81 error = -EREMOTEIO;
82 }
83
84 /* read the actual data */
85 ret = usb_bulk_msg(usb_dev,
86 usb_rcvbulkpipe(usb_dev, VPRBRD_EP_IN), rmsg,
87 bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);
88
89 if ((ret < 0) || (bytes_xfer != bytes_actual)) {
90 dev_err(&usb_dev->dev, "failure receiving usb\n");
91 error = -EREMOTEIO;
92 }
93 return error;
94 }
95
vprbrd_i2c_addr(struct usb_device * usb_dev,struct vprbrd_i2c_addr_msg * amsg)96 static int vprbrd_i2c_addr(struct usb_device *usb_dev,
97 struct vprbrd_i2c_addr_msg *amsg)
98 {
99 int ret, bytes_actual;
100
101 ret = usb_bulk_msg(usb_dev,
102 usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), amsg,
103 sizeof(struct vprbrd_i2c_addr_msg), &bytes_actual,
104 VPRBRD_USB_TIMEOUT_MS);
105
106 if ((ret < 0) ||
107 (sizeof(struct vprbrd_i2c_addr_msg) != bytes_actual)) {
108 dev_err(&usb_dev->dev, "failure transmitting usb\n");
109 return -EREMOTEIO;
110 }
111 return 0;
112 }
113
vprbrd_i2c_read(struct vprbrd * vb,struct i2c_msg * msg)114 static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)
115 {
116 int ret;
117 u16 remain_len, len1, len2, start = 0x0000;
118 struct vprbrd_i2c_read_msg *rmsg =
119 (struct vprbrd_i2c_read_msg *)vb->buf;
120
121 remain_len = msg->len;
122 rmsg->header.cmd = VPRBRD_I2C_CMD_READ;
123 while (remain_len > 0) {
124 rmsg->header.addr = cpu_to_le16(start + 0x4000);
125 if (remain_len <= 255) {
126 len1 = remain_len;
127 len2 = 0x00;
128 rmsg->header.len0 = remain_len;
129 rmsg->header.len1 = 0x00;
130 rmsg->header.len2 = 0x00;
131 rmsg->header.len3 = 0x00;
132 rmsg->header.len4 = 0x00;
133 rmsg->header.len5 = 0x00;
134 remain_len = 0;
135 } else if (remain_len <= 510) {
136 len1 = remain_len;
137 len2 = 0x00;
138 rmsg->header.len0 = remain_len - 255;
139 rmsg->header.len1 = 0xff;
140 rmsg->header.len2 = 0x00;
141 rmsg->header.len3 = 0x00;
142 rmsg->header.len4 = 0x00;
143 rmsg->header.len5 = 0x00;
144 remain_len = 0;
145 } else if (remain_len <= 512) {
146 len1 = remain_len;
147 len2 = 0x00;
148 rmsg->header.len0 = remain_len - 510;
149 rmsg->header.len1 = 0xff;
150 rmsg->header.len2 = 0xff;
151 rmsg->header.len3 = 0x00;
152 rmsg->header.len4 = 0x00;
153 rmsg->header.len5 = 0x00;
154 remain_len = 0;
155 } else if (remain_len <= 767) {
156 len1 = 512;
157 len2 = remain_len - 512;
158 rmsg->header.len0 = 0x02;
159 rmsg->header.len1 = 0xff;
160 rmsg->header.len2 = 0xff;
161 rmsg->header.len3 = remain_len - 512;
162 rmsg->header.len4 = 0x00;
163 rmsg->header.len5 = 0x00;
164 remain_len = 0;
165 } else if (remain_len <= 1022) {
166 len1 = 512;
167 len2 = remain_len - 512;
168 rmsg->header.len0 = 0x02;
169 rmsg->header.len1 = 0xff;
170 rmsg->header.len2 = 0xff;
171 rmsg->header.len3 = remain_len - 767;
172 rmsg->header.len4 = 0xff;
173 rmsg->header.len5 = 0x00;
174 remain_len = 0;
175 } else if (remain_len <= 1024) {
176 len1 = 512;
177 len2 = remain_len - 512;
178 rmsg->header.len0 = 0x02;
179 rmsg->header.len1 = 0xff;
180 rmsg->header.len2 = 0xff;
181 rmsg->header.len3 = remain_len - 1022;
182 rmsg->header.len4 = 0xff;
183 rmsg->header.len5 = 0xff;
184 remain_len = 0;
185 } else {
186 len1 = 512;
187 len2 = 512;
188 rmsg->header.len0 = 0x02;
189 rmsg->header.len1 = 0xff;
190 rmsg->header.len2 = 0xff;
191 rmsg->header.len3 = 0x02;
192 rmsg->header.len4 = 0xff;
193 rmsg->header.len5 = 0xff;
194 remain_len -= 1024;
195 start += 1024;
196 }
197 rmsg->header.tf1 = cpu_to_le16(len1);
198 rmsg->header.tf2 = cpu_to_le16(len2);
199
200 /* first read transfer */
201 ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);
202 if (ret < 0)
203 return ret;
204 /* copy the received data */
205 memcpy(msg->buf + start, rmsg, len1);
206
207 /* second read transfer if neccessary */
208 if (len2 > 0) {
209 ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);
210 if (ret < 0)
211 return ret;
212 /* copy the received data */
213 memcpy(msg->buf + start + 512, rmsg, len2);
214 }
215 }
216 return 0;
217 }
218
vprbrd_i2c_write(struct vprbrd * vb,struct i2c_msg * msg)219 static int vprbrd_i2c_write(struct vprbrd *vb, struct i2c_msg *msg)
220 {
221 int ret, bytes_actual;
222 u16 remain_len, bytes_xfer,
223 start = 0x0000;
224 struct vprbrd_i2c_write_msg *wmsg =
225 (struct vprbrd_i2c_write_msg *)vb->buf;
226
227 remain_len = msg->len;
228 wmsg->header.cmd = VPRBRD_I2C_CMD_WRITE;
229 wmsg->header.last = 0x00;
230 wmsg->header.chan = 0x00;
231 wmsg->header.spi = 0x0000;
232 while (remain_len > 0) {
233 wmsg->header.addr = cpu_to_le16(start + 0x4000);
234 if (remain_len > 503) {
235 wmsg->header.len1 = 0xff;
236 wmsg->header.len2 = 0xf8;
237 remain_len -= 503;
238 bytes_xfer = 503 + sizeof(struct vprbrd_i2c_write_hdr);
239 start += 503;
240 } else if (remain_len > 255) {
241 wmsg->header.len1 = 0xff;
242 wmsg->header.len2 = (remain_len - 255);
243 bytes_xfer = remain_len +
244 sizeof(struct vprbrd_i2c_write_hdr);
245 remain_len = 0;
246 } else {
247 wmsg->header.len1 = remain_len;
248 wmsg->header.len2 = 0x00;
249 bytes_xfer = remain_len +
250 sizeof(struct vprbrd_i2c_write_hdr);
251 remain_len = 0;
252 }
253 memcpy(wmsg->data, msg->buf + start,
254 bytes_xfer - sizeof(struct vprbrd_i2c_write_hdr));
255
256 ret = usb_bulk_msg(vb->usb_dev,
257 usb_sndbulkpipe(vb->usb_dev,
258 VPRBRD_EP_OUT), wmsg,
259 bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);
260 if ((ret < 0) || (bytes_xfer != bytes_actual))
261 return -EREMOTEIO;
262 }
263 return 0;
264 }
265
vprbrd_i2c_xfer(struct i2c_adapter * i2c,struct i2c_msg * msgs,int num)266 static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,
267 int num)
268 {
269 struct i2c_msg *pmsg;
270 int i, ret,
271 error = 0;
272 struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
273 struct vprbrd_i2c_addr_msg *amsg =
274 (struct vprbrd_i2c_addr_msg *)vb->buf;
275 struct vprbrd_i2c_status *smsg = (struct vprbrd_i2c_status *)vb->buf;
276
277 for (i = 0 ; i < num ; i++) {
278 pmsg = &msgs[i];
279
280 dev_dbg(&i2c->dev,
281 " %d: %s (flags %d) %d bytes to 0x%02x\n",
282 i, str_read_write(pmsg->flags & I2C_M_RD),
283 pmsg->flags, pmsg->len, pmsg->addr);
284
285 mutex_lock(&vb->lock);
286 /* directly send the message */
287 if (pmsg->flags & I2C_M_RD) {
288 /* read data */
289 amsg->cmd = VPRBRD_I2C_CMD_ADDR;
290 amsg->unknown2 = 0x00;
291 amsg->unknown3 = 0x00;
292 amsg->addr = pmsg->addr;
293 amsg->unknown1 = 0x01;
294 amsg->len = cpu_to_le16(pmsg->len);
295 /* send the addr and len, we're interested to board */
296 ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
297 if (ret < 0)
298 error = ret;
299
300 ret = vprbrd_i2c_read(vb, pmsg);
301 if (ret < 0)
302 error = ret;
303
304 ret = vprbrd_i2c_status(i2c, smsg, error);
305 if (ret < 0)
306 error = ret;
307 /* in case of protocol error, return the error */
308 if (error < 0)
309 goto error;
310 } else {
311 /* write data */
312 ret = vprbrd_i2c_write(vb, pmsg);
313
314 amsg->cmd = VPRBRD_I2C_CMD_ADDR;
315 amsg->unknown2 = 0x00;
316 amsg->unknown3 = 0x00;
317 amsg->addr = pmsg->addr;
318 amsg->unknown1 = 0x00;
319 amsg->len = cpu_to_le16(pmsg->len);
320 /* send the addr, the data goes to to board */
321 ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
322 if (ret < 0)
323 error = ret;
324
325 ret = vprbrd_i2c_status(i2c, smsg, error);
326 if (ret < 0)
327 error = ret;
328
329 if (error < 0)
330 goto error;
331 }
332 mutex_unlock(&vb->lock);
333 }
334 return num;
335 error:
336 mutex_unlock(&vb->lock);
337 return error;
338 }
339
vprbrd_i2c_func(struct i2c_adapter * i2c)340 static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)
341 {
342 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
343 }
344
345 /* This is the actual algorithm we define */
346 static const struct i2c_algorithm vprbrd_algorithm = {
347 .xfer = vprbrd_i2c_xfer,
348 .functionality = vprbrd_i2c_func,
349 };
350
351 static const struct i2c_adapter_quirks vprbrd_quirks = {
352 .max_read_len = 2048,
353 .max_write_len = 2048,
354 };
355
vprbrd_i2c_probe(struct platform_device * pdev)356 static int vprbrd_i2c_probe(struct platform_device *pdev)
357 {
358 struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
359 struct vprbrd_i2c *vb_i2c;
360 int ret;
361 int pipe;
362
363 vb_i2c = devm_kzalloc(&pdev->dev, sizeof(*vb_i2c), GFP_KERNEL);
364 if (vb_i2c == NULL)
365 return -ENOMEM;
366
367 /* setup i2c adapter description */
368 vb_i2c->i2c.owner = THIS_MODULE;
369 vb_i2c->i2c.class = I2C_CLASS_HWMON;
370 vb_i2c->i2c.algo = &vprbrd_algorithm;
371 vb_i2c->i2c.quirks = &vprbrd_quirks;
372 vb_i2c->i2c.algo_data = vb;
373 /* save the param in usb capabable memory */
374 vb_i2c->bus_freq_param = i2c_bus_param;
375
376 snprintf(vb_i2c->i2c.name, sizeof(vb_i2c->i2c.name),
377 "viperboard at bus %03d device %03d",
378 vb->usb_dev->bus->busnum, vb->usb_dev->devnum);
379
380 /* setting the bus frequency */
381 if ((i2c_bus_param <= VPRBRD_I2C_FREQ_10KHZ)
382 && (i2c_bus_param >= VPRBRD_I2C_FREQ_6MHZ)) {
383 pipe = usb_sndctrlpipe(vb->usb_dev, 0);
384 ret = usb_control_msg(vb->usb_dev, pipe,
385 VPRBRD_USB_REQUEST_I2C_FREQ, VPRBRD_USB_TYPE_OUT,
386 0x0000, 0x0000, &vb_i2c->bus_freq_param, 1,
387 VPRBRD_USB_TIMEOUT_MS);
388 if (ret != 1)
389 return dev_err_probe(&pdev->dev, -EIO,
390 "failure setting i2c_bus_freq to %d\n",
391 i2c_bus_freq);
392 } else {
393 return dev_err_probe(&pdev->dev, -EIO,
394 "invalid i2c_bus_freq setting:%d\n", i2c_bus_freq);
395 }
396
397 vb_i2c->i2c.dev.parent = &pdev->dev;
398
399 /* attach to i2c layer */
400 i2c_add_adapter(&vb_i2c->i2c);
401
402 platform_set_drvdata(pdev, vb_i2c);
403
404 return 0;
405 }
406
vprbrd_i2c_remove(struct platform_device * pdev)407 static void vprbrd_i2c_remove(struct platform_device *pdev)
408 {
409 struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);
410
411 i2c_del_adapter(&vb_i2c->i2c);
412 }
413
414 static struct platform_driver vprbrd_i2c_driver = {
415 .driver.name = "viperboard-i2c",
416 .probe = vprbrd_i2c_probe,
417 .remove = vprbrd_i2c_remove,
418 };
419
vprbrd_i2c_init(void)420 static int __init vprbrd_i2c_init(void)
421 {
422 switch (i2c_bus_freq) {
423 case 6000:
424 i2c_bus_param = VPRBRD_I2C_FREQ_6MHZ;
425 break;
426 case 3000:
427 i2c_bus_param = VPRBRD_I2C_FREQ_3MHZ;
428 break;
429 case 1000:
430 i2c_bus_param = VPRBRD_I2C_FREQ_1MHZ;
431 break;
432 case 400:
433 i2c_bus_param = VPRBRD_I2C_FREQ_400KHZ;
434 break;
435 case 200:
436 i2c_bus_param = VPRBRD_I2C_FREQ_200KHZ;
437 break;
438 case 100:
439 i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
440 break;
441 case 10:
442 i2c_bus_param = VPRBRD_I2C_FREQ_10KHZ;
443 break;
444 default:
445 pr_warn("invalid i2c_bus_freq (%d)\n", i2c_bus_freq);
446 i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
447 }
448
449 return platform_driver_register(&vprbrd_i2c_driver);
450 }
451 subsys_initcall(vprbrd_i2c_init);
452
vprbrd_i2c_exit(void)453 static void __exit vprbrd_i2c_exit(void)
454 {
455 platform_driver_unregister(&vprbrd_i2c_driver);
456 }
457 module_exit(vprbrd_i2c_exit);
458
459 MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
460 MODULE_DESCRIPTION("I2C controller driver for Nano River Techs Viperboard");
461 MODULE_LICENSE("GPL");
462 MODULE_ALIAS("platform:viperboard-i2c");
463