i2c-viperboard.c

  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
 24struct vprbrd_i2c {
 25	struct i2c_adapter i2c;
 26	u8 bus_freq_param;
 27};
 28
 29/* i2c bus frequency module parameter */
 30static u8 i2c_bus_param;
 31static unsigned int i2c_bus_freq = 100;
 32module_param(i2c_bus_freq, int, 0);
 33MODULE_PARM_DESC(i2c_bus_freq,
 34	"i2c bus frequency in khz (default is 100) valid values: 10, 100, 200, 400, 1000, 3000, 6000");
 35
 36static 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
 66static 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
 96static 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
114static 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 necessary */
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
219static 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
266static 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;
335error:
336	mutex_unlock(&vb->lock);
337	return error;
338}
339
340static 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 */
346static const struct i2c_algorithm vprbrd_algorithm = {
347	.xfer = vprbrd_i2c_xfer,
348	.functionality = vprbrd_i2c_func,
349};
350
351static const struct i2c_adapter_quirks vprbrd_quirks = {
352	.max_read_len = 2048,
353	.max_write_len = 2048,
354};
355
356static 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
407static 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
414static struct platform_driver vprbrd_i2c_driver = {
415	.driver.name	= "viperboard-i2c",
416	.probe		= vprbrd_i2c_probe,
417	.remove		= vprbrd_i2c_remove,
418};
419
420static 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}
451subsys_initcall(vprbrd_i2c_init);
452
453static void __exit vprbrd_i2c_exit(void)
454{
455	platform_driver_unregister(&vprbrd_i2c_driver);
456}
457module_exit(vprbrd_i2c_exit);
458
459MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
460MODULE_DESCRIPTION("I2C controller driver for Nano River Techs Viperboard");
461MODULE_LICENSE("GPL");
462MODULE_ALIAS("platform:viperboard-i2c");