1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Nano River Technologies viperboard i2c master 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/types.h>
15#include <linux/mutex.h>
16#include <linux/platform_device.h>
17
18#include <linux/usb.h>
19#include <linux/i2c.h>
20
21#include <linux/mfd/viperboard.h>
22
23struct vprbrd_i2c {
24	struct i2c_adapter i2c;
25	u8 bus_freq_param;
26};
27
28/* i2c bus frequency module parameter */
29static u8 i2c_bus_param;
30static unsigned int i2c_bus_freq = 100;
31module_param(i2c_bus_freq, int, 0);
32MODULE_PARM_DESC(i2c_bus_freq,
33	"i2c bus frequency in khz (default is 100) valid values: 10, 100, 200, 400, 1000, 3000, 6000");
34
35static int vprbrd_i2c_status(struct i2c_adapter *i2c,
36	struct vprbrd_i2c_status *status, bool prev_error)
37{
38	u16 bytes_xfer;
39	int ret;
40	struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
41
42	/* check for protocol error */
43	bytes_xfer = sizeof(struct vprbrd_i2c_status);
44
45	ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
46		VPRBRD_USB_REQUEST_I2C, VPRBRD_USB_TYPE_IN, 0x0000, 0x0000,
47		status, bytes_xfer, VPRBRD_USB_TIMEOUT_MS);
48
49	if (ret != bytes_xfer)
50		prev_error = true;
51
52	if (prev_error) {
53		dev_err(&i2c->dev, "failure in usb communication\n");
54		return -EREMOTEIO;
55	}
56
57	dev_dbg(&i2c->dev, "  status = %d\n", status->status);
58	if (status->status != 0x00) {
59		dev_err(&i2c->dev, "failure: i2c protocol error\n");
60		return -EPROTO;
61	}
62	return 0;
63}
64
65static int vprbrd_i2c_receive(struct usb_device *usb_dev,
66	struct vprbrd_i2c_read_msg *rmsg, int bytes_xfer)
67{
68	int ret, bytes_actual;
69	int error = 0;
70
71	/* send the read request */
72	ret = usb_bulk_msg(usb_dev,
73		usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), rmsg,
74		sizeof(struct vprbrd_i2c_read_hdr), &bytes_actual,
75		VPRBRD_USB_TIMEOUT_MS);
76
77	if ((ret < 0)
78		|| (bytes_actual != sizeof(struct vprbrd_i2c_read_hdr))) {
79		dev_err(&usb_dev->dev, "failure transmitting usb\n");
80		error = -EREMOTEIO;
81	}
82
83	/* read the actual data */
84	ret = usb_bulk_msg(usb_dev,
85		usb_rcvbulkpipe(usb_dev, VPRBRD_EP_IN), rmsg,
86		bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);
87
88	if ((ret < 0) || (bytes_xfer != bytes_actual)) {
89		dev_err(&usb_dev->dev, "failure receiving usb\n");
90		error = -EREMOTEIO;
91	}
92	return error;
93}
94
95static int vprbrd_i2c_addr(struct usb_device *usb_dev,
96	struct vprbrd_i2c_addr_msg *amsg)
97{
98	int ret, bytes_actual;
99
100	ret = usb_bulk_msg(usb_dev,
101		usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), amsg,
102		sizeof(struct vprbrd_i2c_addr_msg), &bytes_actual,
103		VPRBRD_USB_TIMEOUT_MS);
104
105	if ((ret < 0) ||
106			(sizeof(struct vprbrd_i2c_addr_msg) != bytes_actual)) {
107		dev_err(&usb_dev->dev, "failure transmitting usb\n");
108		return -EREMOTEIO;
109	}
110	return 0;
111}
112
113static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)
114{
115	int ret;
116	u16 remain_len, len1, len2, start = 0x0000;
117	struct vprbrd_i2c_read_msg *rmsg =
118		(struct vprbrd_i2c_read_msg *)vb->buf;
119
120	remain_len = msg->len;
121	rmsg->header.cmd = VPRBRD_I2C_CMD_READ;
122	while (remain_len > 0) {
123		rmsg->header.addr = cpu_to_le16(start + 0x4000);
124		if (remain_len <= 255) {
125			len1 = remain_len;
126			len2 = 0x00;
127			rmsg->header.len0 = remain_len;
128			rmsg->header.len1 = 0x00;
129			rmsg->header.len2 = 0x00;
130			rmsg->header.len3 = 0x00;
131			rmsg->header.len4 = 0x00;
132			rmsg->header.len5 = 0x00;
133			remain_len = 0;
134		} else if (remain_len <= 510) {
135			len1 = remain_len;
136			len2 = 0x00;
137			rmsg->header.len0 = remain_len - 255;
138			rmsg->header.len1 = 0xff;
139			rmsg->header.len2 = 0x00;
140			rmsg->header.len3 = 0x00;
141			rmsg->header.len4 = 0x00;
142			rmsg->header.len5 = 0x00;
143			remain_len = 0;
144		} else if (remain_len <= 512) {
145			len1 = remain_len;
146			len2 = 0x00;
147			rmsg->header.len0 = remain_len - 510;
148			rmsg->header.len1 = 0xff;
149			rmsg->header.len2 = 0xff;
150			rmsg->header.len3 = 0x00;
151			rmsg->header.len4 = 0x00;
152			rmsg->header.len5 = 0x00;
153			remain_len = 0;
154		} else if (remain_len <= 767) {
155			len1 = 512;
156			len2 = remain_len - 512;
157			rmsg->header.len0 = 0x02;
158			rmsg->header.len1 = 0xff;
159			rmsg->header.len2 = 0xff;
160			rmsg->header.len3 = remain_len - 512;
161			rmsg->header.len4 = 0x00;
162			rmsg->header.len5 = 0x00;
163			remain_len = 0;
164		} else if (remain_len <= 1022) {
165			len1 = 512;
166			len2 = remain_len - 512;
167			rmsg->header.len0 = 0x02;
168			rmsg->header.len1 = 0xff;
169			rmsg->header.len2 = 0xff;
170			rmsg->header.len3 = remain_len - 767;
171			rmsg->header.len4 = 0xff;
172			rmsg->header.len5 = 0x00;
173			remain_len = 0;
174		} else if (remain_len <= 1024) {
175			len1 = 512;
176			len2 = remain_len - 512;
177			rmsg->header.len0 = 0x02;
178			rmsg->header.len1 = 0xff;
179			rmsg->header.len2 = 0xff;
180			rmsg->header.len3 = remain_len - 1022;
181			rmsg->header.len4 = 0xff;
182			rmsg->header.len5 = 0xff;
183			remain_len = 0;
184		} else {
185			len1 = 512;
186			len2 = 512;
187			rmsg->header.len0 = 0x02;
188			rmsg->header.len1 = 0xff;
189			rmsg->header.len2 = 0xff;
190			rmsg->header.len3 = 0x02;
191			rmsg->header.len4 = 0xff;
192			rmsg->header.len5 = 0xff;
193			remain_len -= 1024;
194			start += 1024;
195		}
196		rmsg->header.tf1 = cpu_to_le16(len1);
197		rmsg->header.tf2 = cpu_to_le16(len2);
198
199		/* first read transfer */
200		ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);
201		if (ret < 0)
202			return ret;
203		/* copy the received data */
204		memcpy(msg->buf + start, rmsg, len1);
205
206		/* second read transfer if neccessary */
207		if (len2 > 0) {
208			ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);
209			if (ret < 0)
210				return ret;
211			/* copy the received data */
212			memcpy(msg->buf + start + 512, rmsg, len2);
213		}
214	}
215	return 0;
216}
217
218static int vprbrd_i2c_write(struct vprbrd *vb, struct i2c_msg *msg)
219{
220	int ret, bytes_actual;
221	u16 remain_len, bytes_xfer,
222		start = 0x0000;
223	struct vprbrd_i2c_write_msg *wmsg =
224		(struct vprbrd_i2c_write_msg *)vb->buf;
225
226	remain_len = msg->len;
227	wmsg->header.cmd = VPRBRD_I2C_CMD_WRITE;
228	wmsg->header.last = 0x00;
229	wmsg->header.chan = 0x00;
230	wmsg->header.spi = 0x0000;
231	while (remain_len > 0) {
232		wmsg->header.addr = cpu_to_le16(start + 0x4000);
233		if (remain_len > 503) {
234			wmsg->header.len1 = 0xff;
235			wmsg->header.len2 = 0xf8;
236			remain_len -= 503;
237			bytes_xfer = 503 + sizeof(struct vprbrd_i2c_write_hdr);
238			start += 503;
239		} else if (remain_len > 255) {
240			wmsg->header.len1 = 0xff;
241			wmsg->header.len2 = (remain_len - 255);
242			bytes_xfer = remain_len +
243				sizeof(struct vprbrd_i2c_write_hdr);
244			remain_len = 0;
245		} else {
246			wmsg->header.len1 = remain_len;
247			wmsg->header.len2 = 0x00;
248			bytes_xfer = remain_len +
249				sizeof(struct vprbrd_i2c_write_hdr);
250			remain_len = 0;
251		}
252		memcpy(wmsg->data, msg->buf + start,
253			bytes_xfer - sizeof(struct vprbrd_i2c_write_hdr));
254
255		ret = usb_bulk_msg(vb->usb_dev,
256			usb_sndbulkpipe(vb->usb_dev,
257			VPRBRD_EP_OUT), wmsg,
258			bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);
259		if ((ret < 0) || (bytes_xfer != bytes_actual))
260			return -EREMOTEIO;
261	}
262	return 0;
263}
264
265static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,
266		int num)
267{
268	struct i2c_msg *pmsg;
269	int i, ret,
270		error = 0;
271	struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
272	struct vprbrd_i2c_addr_msg *amsg =
273		(struct vprbrd_i2c_addr_msg *)vb->buf;
274	struct vprbrd_i2c_status *smsg = (struct vprbrd_i2c_status *)vb->buf;
275
276	dev_dbg(&i2c->dev, "master xfer %d messages:\n", num);
277
278	for (i = 0 ; i < num ; i++) {
279		pmsg = &msgs[i];
280
281		dev_dbg(&i2c->dev,
282			"  %d: %s (flags %d) %d bytes to 0x%02x\n",
283			i, pmsg->flags & I2C_M_RD ? "read" : "write",
284			pmsg->flags, pmsg->len, pmsg->addr);
285
286		mutex_lock(&vb->lock);
287		/* directly send the message */
288		if (pmsg->flags & I2C_M_RD) {
289			/* read data */
290			amsg->cmd = VPRBRD_I2C_CMD_ADDR;
291			amsg->unknown2 = 0x00;
292			amsg->unknown3 = 0x00;
293			amsg->addr = pmsg->addr;
294			amsg->unknown1 = 0x01;
295			amsg->len = cpu_to_le16(pmsg->len);
296			/* send the addr and len, we're interested to board */
297			ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
298			if (ret < 0)
299				error = ret;
300
301			ret = vprbrd_i2c_read(vb, pmsg);
302			if (ret < 0)
303				error = ret;
304
305			ret = vprbrd_i2c_status(i2c, smsg, error);
306			if (ret < 0)
307				error = ret;
308			/* in case of protocol error, return the error */
309			if (error < 0)
310				goto error;
311		} else {
312			/* write data */
313			ret = vprbrd_i2c_write(vb, pmsg);
314
315			amsg->cmd = VPRBRD_I2C_CMD_ADDR;
316			amsg->unknown2 = 0x00;
317			amsg->unknown3 = 0x00;
318			amsg->addr = pmsg->addr;
319			amsg->unknown1 = 0x00;
320			amsg->len = cpu_to_le16(pmsg->len);
321			/* send the addr, the data goes to to board */
322			ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
323			if (ret < 0)
324				error = ret;
325
326			ret = vprbrd_i2c_status(i2c, smsg, error);
327			if (ret < 0)
328				error = ret;
329
330			if (error < 0)
331				goto error;
332		}
333		mutex_unlock(&vb->lock);
334	}
335	return num;
336error:
337	mutex_unlock(&vb->lock);
338	return error;
339}
340
341static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)
342{
343	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
344}
345
346/* This is the actual algorithm we define */
347static const struct i2c_algorithm vprbrd_algorithm = {
348	.master_xfer	= vprbrd_i2c_xfer,
349	.functionality	= vprbrd_i2c_func,
350};
351
352static const struct i2c_adapter_quirks vprbrd_quirks = {
353	.max_read_len = 2048,
354	.max_write_len = 2048,
355};
356
357static int vprbrd_i2c_probe(struct platform_device *pdev)
358{
359	struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
360	struct vprbrd_i2c *vb_i2c;
361	int ret;
362	int pipe;
363
364	vb_i2c = devm_kzalloc(&pdev->dev, sizeof(*vb_i2c), GFP_KERNEL);
365	if (vb_i2c == NULL)
366		return -ENOMEM;
367
368	/* setup i2c adapter description */
369	vb_i2c->i2c.owner = THIS_MODULE;
370	vb_i2c->i2c.class = I2C_CLASS_HWMON;
371	vb_i2c->i2c.algo = &vprbrd_algorithm;
372	vb_i2c->i2c.quirks = &vprbrd_quirks;
373	vb_i2c->i2c.algo_data = vb;
374	/* save the param in usb capabable memory */
375	vb_i2c->bus_freq_param = i2c_bus_param;
376
377	snprintf(vb_i2c->i2c.name, sizeof(vb_i2c->i2c.name),
378		 "viperboard at bus %03d device %03d",
379		 vb->usb_dev->bus->busnum, vb->usb_dev->devnum);
380
381	/* setting the bus frequency */
382	if ((i2c_bus_param <= VPRBRD_I2C_FREQ_10KHZ)
383		&& (i2c_bus_param >= VPRBRD_I2C_FREQ_6MHZ)) {
384		pipe = usb_sndctrlpipe(vb->usb_dev, 0);
385		ret = usb_control_msg(vb->usb_dev, pipe,
386			VPRBRD_USB_REQUEST_I2C_FREQ, VPRBRD_USB_TYPE_OUT,
387			0x0000, 0x0000, &vb_i2c->bus_freq_param, 1,
388			VPRBRD_USB_TIMEOUT_MS);
389		if (ret != 1) {
390			dev_err(&pdev->dev, "failure setting i2c_bus_freq to %d\n",
391				i2c_bus_freq);
392			return -EIO;
393		}
394	} else {
395		dev_err(&pdev->dev,
396			"invalid i2c_bus_freq setting:%d\n", i2c_bus_freq);
397		return -EIO;
398	}
399
400	vb_i2c->i2c.dev.parent = &pdev->dev;
401
402	/* attach to i2c layer */
403	i2c_add_adapter(&vb_i2c->i2c);
404
405	platform_set_drvdata(pdev, vb_i2c);
406
407	return 0;
408}
409
410static void vprbrd_i2c_remove(struct platform_device *pdev)
411{
412	struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);
413
414	i2c_del_adapter(&vb_i2c->i2c);
415}
416
417static struct platform_driver vprbrd_i2c_driver = {
418	.driver.name	= "viperboard-i2c",
419	.driver.owner	= THIS_MODULE,
420	.probe		= vprbrd_i2c_probe,
421	.remove_new	= vprbrd_i2c_remove,
422};
423
424static int __init vprbrd_i2c_init(void)
425{
426	switch (i2c_bus_freq) {
427	case 6000:
428		i2c_bus_param = VPRBRD_I2C_FREQ_6MHZ;
429		break;
430	case 3000:
431		i2c_bus_param = VPRBRD_I2C_FREQ_3MHZ;
432		break;
433	case 1000:
434		i2c_bus_param = VPRBRD_I2C_FREQ_1MHZ;
435		break;
436	case 400:
437		i2c_bus_param = VPRBRD_I2C_FREQ_400KHZ;
438		break;
439	case 200:
440		i2c_bus_param = VPRBRD_I2C_FREQ_200KHZ;
441		break;
442	case 100:
443		i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
444		break;
445	case 10:
446		i2c_bus_param = VPRBRD_I2C_FREQ_10KHZ;
447		break;
448	default:
449		pr_warn("invalid i2c_bus_freq (%d)\n", i2c_bus_freq);
450		i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
451	}
452
453	return platform_driver_register(&vprbrd_i2c_driver);
454}
455subsys_initcall(vprbrd_i2c_init);
456
457static void __exit vprbrd_i2c_exit(void)
458{
459	platform_driver_unregister(&vprbrd_i2c_driver);
460}
461module_exit(vprbrd_i2c_exit);
462
463MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
464MODULE_DESCRIPTION("I2C master driver for Nano River Techs Viperboard");
465MODULE_LICENSE("GPL");
466MODULE_ALIAS("platform:viperboard-i2c");
467