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/drivers/media/common/saa7146_i2c.c

https://bitbucket.org/ndreys/linux-sunxi
C | 421 lines | 265 code | 70 blank | 86 comment | 75 complexity | abbb325be8735aa3a28f50fd494a4d9c MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1#include <media/saa7146_vv.h>
  2
  3static u32 saa7146_i2c_func(struct i2c_adapter *adapter)
  4{
  5//fm	DEB_I2C(("'%s'.\n", adapter->name));
  6
  7	return	  I2C_FUNC_I2C
  8		| I2C_FUNC_SMBUS_QUICK
  9		| I2C_FUNC_SMBUS_READ_BYTE	| I2C_FUNC_SMBUS_WRITE_BYTE
 10		| I2C_FUNC_SMBUS_READ_BYTE_DATA | I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
 11}
 12
 13/* this function returns the status-register of our i2c-device */
 14static inline u32 saa7146_i2c_status(struct saa7146_dev *dev)
 15{
 16	u32 iicsta = saa7146_read(dev, I2C_STATUS);
 17/*
 18	DEB_I2C(("status: 0x%08x\n",iicsta));
 19*/
 20	return iicsta;
 21}
 22
 23/* this function runs through the i2c-messages and prepares the data to be
 24   sent through the saa7146. have a look at the specifications p. 122 ff
 25   to understand this. it returns the number of u32s to send, or -1
 26   in case of an error. */
 27static int saa7146_i2c_msg_prepare(const struct i2c_msg *m, int num, __le32 *op)
 28{
 29	int h1, h2;
 30	int i, j, addr;
 31	int mem = 0, op_count = 0;
 32
 33	/* first determine size of needed memory */
 34	for(i = 0; i < num; i++) {
 35		mem += m[i].len + 1;
 36	}
 37
 38	/* worst case: we need one u32 for three bytes to be send
 39	   plus one extra byte to address the device */
 40	mem = 1 + ((mem-1) / 3);
 41
 42	/* we assume that op points to a memory of at least SAA7146_I2C_MEM bytes
 43	   size. if we exceed this limit... */
 44	if ( (4*mem) > SAA7146_I2C_MEM ) {
 45//fm		DEB_I2C(("cannot prepare i2c-message.\n"));
 46		return -ENOMEM;
 47	}
 48
 49	/* be careful: clear out the i2c-mem first */
 50	memset(op,0,sizeof(__le32)*mem);
 51
 52	/* loop through all messages */
 53	for(i = 0; i < num; i++) {
 54
 55		/* insert the address of the i2c-slave.
 56		   note: we get 7 bit i2c-addresses,
 57		   so we have to perform a translation */
 58		addr = (m[i].addr*2) + ( (0 != (m[i].flags & I2C_M_RD)) ? 1 : 0);
 59		h1 = op_count/3; h2 = op_count%3;
 60		op[h1] |= cpu_to_le32(	    (u8)addr << ((3-h2)*8));
 61		op[h1] |= cpu_to_le32(SAA7146_I2C_START << ((3-h2)*2));
 62		op_count++;
 63
 64		/* loop through all bytes of message i */
 65		for(j = 0; j < m[i].len; j++) {
 66			/* insert the data bytes */
 67			h1 = op_count/3; h2 = op_count%3;
 68			op[h1] |= cpu_to_le32( (u32)((u8)m[i].buf[j]) << ((3-h2)*8));
 69			op[h1] |= cpu_to_le32(       SAA7146_I2C_CONT << ((3-h2)*2));
 70			op_count++;
 71		}
 72
 73	}
 74
 75	/* have a look at the last byte inserted:
 76	  if it was: ...CONT change it to ...STOP */
 77	h1 = (op_count-1)/3; h2 = (op_count-1)%3;
 78	if ( SAA7146_I2C_CONT == (0x3 & (le32_to_cpu(op[h1]) >> ((3-h2)*2))) ) {
 79		op[h1] &= ~cpu_to_le32(0x2 << ((3-h2)*2));
 80		op[h1] |= cpu_to_le32(SAA7146_I2C_STOP << ((3-h2)*2));
 81	}
 82
 83	/* return the number of u32s to send */
 84	return mem;
 85}
 86
 87/* this functions loops through all i2c-messages. normally, it should determine
 88   which bytes were read through the adapter and write them back to the corresponding
 89   i2c-message. but instead, we simply write back all bytes.
 90   fixme: this could be improved. */
 91static int saa7146_i2c_msg_cleanup(const struct i2c_msg *m, int num, __le32 *op)
 92{
 93	int i, j;
 94	int op_count = 0;
 95
 96	/* loop through all messages */
 97	for(i = 0; i < num; i++) {
 98
 99		op_count++;
100
101		/* loop through all bytes of message i */
102		for(j = 0; j < m[i].len; j++) {
103			/* write back all bytes that could have been read */
104			m[i].buf[j] = (le32_to_cpu(op[op_count/3]) >> ((3-(op_count%3))*8));
105			op_count++;
106		}
107	}
108
109	return 0;
110}
111
112/* this functions resets the i2c-device and returns 0 if everything was fine, otherwise -1 */
113static int saa7146_i2c_reset(struct saa7146_dev *dev)
114{
115	/* get current status */
116	u32 status = saa7146_i2c_status(dev);
117
118	/* clear registers for sure */
119	saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
120	saa7146_write(dev, I2C_TRANSFER, 0);
121
122	/* check if any operation is still in progress */
123	if ( 0 != ( status & SAA7146_I2C_BUSY) ) {
124
125		/* yes, kill ongoing operation */
126		DEB_I2C(("busy_state detected.\n"));
127
128		/* set "ABORT-OPERATION"-bit (bit 7)*/
129		saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
130		saa7146_write(dev, MC2, (MASK_00 | MASK_16));
131		msleep(SAA7146_I2C_DELAY);
132
133		/* clear all error-bits pending; this is needed because p.123, note 1 */
134		saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
135		saa7146_write(dev, MC2, (MASK_00 | MASK_16));
136		msleep(SAA7146_I2C_DELAY);
137	}
138
139	/* check if any error is (still) present. (this can be necessary because p.123, note 1) */
140	status = saa7146_i2c_status(dev);
141
142	if ( dev->i2c_bitrate != status ) {
143
144		DEB_I2C(("error_state detected. status:0x%08x\n",status));
145
146		/* Repeat the abort operation. This seems to be necessary
147		   after serious protocol errors caused by e.g. the SAA7740 */
148		saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07));
149		saa7146_write(dev, MC2, (MASK_00 | MASK_16));
150		msleep(SAA7146_I2C_DELAY);
151
152		/* clear all error-bits pending */
153		saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
154		saa7146_write(dev, MC2, (MASK_00 | MASK_16));
155		msleep(SAA7146_I2C_DELAY);
156
157		/* the data sheet says it might be necessary to clear the status
158		   twice after an abort */
159		saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate);
160		saa7146_write(dev, MC2, (MASK_00 | MASK_16));
161		msleep(SAA7146_I2C_DELAY);
162	}
163
164	/* if any error is still present, a fatal error has occurred ... */
165	status = saa7146_i2c_status(dev);
166	if ( dev->i2c_bitrate != status ) {
167		DEB_I2C(("fatal error. status:0x%08x\n",status));
168		return -1;
169	}
170
171	return 0;
172}
173
174/* this functions writes out the data-byte 'dword' to the i2c-device.
175   it returns 0 if ok, -1 if the transfer failed, -2 if the transfer
176   failed badly (e.g. address error) */
177static int saa7146_i2c_writeout(struct saa7146_dev *dev, __le32 *dword, int short_delay)
178{
179	u32 status = 0, mc2 = 0;
180	int trial = 0;
181	unsigned long timeout;
182
183	/* write out i2c-command */
184	DEB_I2C(("before: 0x%08x (status: 0x%08x), %d\n",*dword,saa7146_read(dev, I2C_STATUS), dev->i2c_op));
185
186	if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) {
187
188		saa7146_write(dev, I2C_STATUS,	 dev->i2c_bitrate);
189		saa7146_write(dev, I2C_TRANSFER, le32_to_cpu(*dword));
190
191		dev->i2c_op = 1;
192		SAA7146_ISR_CLEAR(dev, MASK_16|MASK_17);
193		SAA7146_IER_ENABLE(dev, MASK_16|MASK_17);
194		saa7146_write(dev, MC2, (MASK_00 | MASK_16));
195
196		timeout = HZ/100 + 1; /* 10ms */
197		timeout = wait_event_interruptible_timeout(dev->i2c_wq, dev->i2c_op == 0, timeout);
198		if (timeout == -ERESTARTSYS || dev->i2c_op) {
199			SAA7146_IER_DISABLE(dev, MASK_16|MASK_17);
200			SAA7146_ISR_CLEAR(dev, MASK_16|MASK_17);
201			if (timeout == -ERESTARTSYS)
202				/* a signal arrived */
203				return -ERESTARTSYS;
204
205			printk(KERN_WARNING "%s %s [irq]: timed out waiting for end of xfer\n",
206				dev->name, __func__);
207			return -EIO;
208		}
209		status = saa7146_read(dev, I2C_STATUS);
210	} else {
211		saa7146_write(dev, I2C_STATUS,	 dev->i2c_bitrate);
212		saa7146_write(dev, I2C_TRANSFER, le32_to_cpu(*dword));
213		saa7146_write(dev, MC2, (MASK_00 | MASK_16));
214
215		/* do not poll for i2c-status before upload is complete */
216		timeout = jiffies + HZ/100 + 1; /* 10ms */
217		while(1) {
218			mc2 = (saa7146_read(dev, MC2) & 0x1);
219			if( 0 != mc2 ) {
220				break;
221			}
222			if (time_after(jiffies,timeout)) {
223				printk(KERN_WARNING "%s %s: timed out waiting for MC2\n",
224					dev->name, __func__);
225				return -EIO;
226			}
227		}
228		/* wait until we get a transfer done or error */
229		timeout = jiffies + HZ/100 + 1; /* 10ms */
230		/* first read usually delivers bogus results... */
231		saa7146_i2c_status(dev);
232		while(1) {
233			status = saa7146_i2c_status(dev);
234			if ((status & 0x3) != 1)
235				break;
236			if (time_after(jiffies,timeout)) {
237				/* this is normal when probing the bus
238				 * (no answer from nonexisistant device...)
239				 */
240				printk(KERN_WARNING "%s %s [poll]: timed out waiting for end of xfer\n",
241					dev->name, __func__);
242				return -EIO;
243			}
244			if (++trial < 50 && short_delay)
245				udelay(10);
246			else
247				msleep(1);
248		}
249	}
250
251	/* give a detailed status report */
252	if ( 0 != (status & (SAA7146_I2C_SPERR | SAA7146_I2C_APERR |
253			     SAA7146_I2C_DTERR | SAA7146_I2C_DRERR |
254			     SAA7146_I2C_AL    | SAA7146_I2C_ERR   |
255			     SAA7146_I2C_BUSY)) ) {
256
257		if ( 0 == (status & SAA7146_I2C_ERR) ||
258		     0 == (status & SAA7146_I2C_BUSY) ) {
259			/* it may take some time until ERR goes high - ignore */
260			DEB_I2C(("unexpected i2c status %04x\n", status));
261		}
262		if( 0 != (status & SAA7146_I2C_SPERR) ) {
263			DEB_I2C(("error due to invalid start/stop condition.\n"));
264		}
265		if( 0 != (status & SAA7146_I2C_DTERR) ) {
266			DEB_I2C(("error in data transmission.\n"));
267		}
268		if( 0 != (status & SAA7146_I2C_DRERR) ) {
269			DEB_I2C(("error when receiving data.\n"));
270		}
271		if( 0 != (status & SAA7146_I2C_AL) ) {
272			DEB_I2C(("error because arbitration lost.\n"));
273		}
274
275		/* we handle address-errors here */
276		if( 0 != (status & SAA7146_I2C_APERR) ) {
277			DEB_I2C(("error in address phase.\n"));
278			return -EREMOTEIO;
279		}
280
281		return -EIO;
282	}
283
284	/* read back data, just in case we were reading ... */
285	*dword = cpu_to_le32(saa7146_read(dev, I2C_TRANSFER));
286
287	DEB_I2C(("after: 0x%08x\n",*dword));
288	return 0;
289}
290
291static int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries)
292{
293	int i = 0, count = 0;
294	__le32 *buffer = dev->d_i2c.cpu_addr;
295	int err = 0;
296	int short_delay = 0;
297
298	if (mutex_lock_interruptible(&dev->i2c_lock))
299		return -ERESTARTSYS;
300
301	for(i=0;i<num;i++) {
302		DEB_I2C(("msg:%d/%d\n",i+1,num));
303	}
304
305	/* prepare the message(s), get number of u32s to transfer */
306	count = saa7146_i2c_msg_prepare(msgs, num, buffer);
307	if ( 0 > count ) {
308		err = -1;
309		goto out;
310	}
311
312	if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) )
313		short_delay = 1;
314
315	do {
316		/* reset the i2c-device if necessary */
317		err = saa7146_i2c_reset(dev);
318		if ( 0 > err ) {
319			DEB_I2C(("could not reset i2c-device.\n"));
320			goto out;
321		}
322
323		/* write out the u32s one after another */
324		for(i = 0; i < count; i++) {
325			err = saa7146_i2c_writeout(dev, &buffer[i], short_delay);
326			if ( 0 != err) {
327				/* this one is unsatisfying: some i2c slaves on some
328				   dvb cards don't acknowledge correctly, so the saa7146
329				   thinks that an address error occurred. in that case, the
330				   transaction should be retrying, even if an address error
331				   occurred. analog saa7146 based cards extensively rely on
332				   i2c address probing, however, and address errors indicate that a
333				   device is really *not* there. retrying in that case
334				   increases the time the device needs to probe greatly, so
335				   it should be avoided. So we bail out in irq mode after an
336				   address error and trust the saa7146 address error detection. */
337				if (-EREMOTEIO == err && 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags))
338					goto out;
339				DEB_I2C(("error while sending message(s). starting again.\n"));
340				break;
341			}
342		}
343		if( 0 == err ) {
344			err = num;
345			break;
346		}
347
348		/* delay a bit before retrying */
349		msleep(10);
350
351	} while (err != num && retries--);
352
353	/* quit if any error occurred */
354	if (err != num)
355		goto out;
356
357	/* if any things had to be read, get the results */
358	if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) {
359		DEB_I2C(("could not cleanup i2c-message.\n"));
360		err = -1;
361		goto out;
362	}
363
364	/* return the number of delivered messages */
365	DEB_I2C(("transmission successful. (msg:%d).\n",err));
366out:
367	/* another bug in revision 0: the i2c-registers get uploaded randomly by other
368	   uploads, so we better clear them out before continuing */
369	if( 0 == dev->revision ) {
370		__le32 zero = 0;
371		saa7146_i2c_reset(dev);
372		if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) {
373			INFO(("revision 0 error. this should never happen.\n"));
374		}
375	}
376
377	mutex_unlock(&dev->i2c_lock);
378	return err;
379}
380
381/* utility functions */
382static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num)
383{
384	struct v4l2_device *v4l2_dev = i2c_get_adapdata(adapter);
385	struct saa7146_dev *dev = to_saa7146_dev(v4l2_dev);
386
387	/* use helper function to transfer data */
388	return saa7146_i2c_transfer(dev, msg, num, adapter->retries);
389}
390
391
392/*****************************************************************************/
393/* i2c-adapter helper functions                                              */
394
395/* exported algorithm data */
396static struct i2c_algorithm saa7146_algo = {
397	.master_xfer	= saa7146_i2c_xfer,
398	.functionality	= saa7146_i2c_func,
399};
400
401int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate)
402{
403	DEB_EE(("bitrate: 0x%08x\n",bitrate));
404
405	/* enable i2c-port pins */
406	saa7146_write(dev, MC1, (MASK_08 | MASK_24));
407
408	dev->i2c_bitrate = bitrate;
409	saa7146_i2c_reset(dev);
410
411	if (i2c_adapter) {
412		i2c_set_adapdata(i2c_adapter, &dev->v4l2_dev);
413		i2c_adapter->dev.parent    = &dev->pci->dev;
414		i2c_adapter->algo	   = &saa7146_algo;
415		i2c_adapter->algo_data     = NULL;
416		i2c_adapter->timeout = SAA7146_I2C_TIMEOUT;
417		i2c_adapter->retries = SAA7146_I2C_RETRIES;
418	}
419
420	return 0;
421}