1/*
2 *  Driver for the Conexant CX25821 PCIe bridge
3 *
4 *  Copyright (C) 2009 Conexant Systems Inc.
5 *  Authors  <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
6 *	Based on Steven Toth <stoth@linuxtv.org> cx23885 driver
7 *
8 *  This program is free software; you can redistribute it and/or modify
9 *  it under the terms of the GNU General Public License as published by
10 *  the Free Software Foundation; either version 2 of the License, or
11 *  (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 *
17 *  GNU General Public License for more details.
18 *
19 *  You should have received a copy of the GNU General Public License
20 *  along with this program; if not, write to the Free Software
21 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23
24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/module.h>
27#include <linux/i2c.h>
28#include "cx25821.h"
29
30static unsigned int i2c_debug;
31module_param(i2c_debug, int, 0644);
32MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
33
34static unsigned int i2c_scan;
35module_param(i2c_scan, int, 0444);
36MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
37
38#define dprintk(level, fmt, arg...)					\
39do {									\
40	if (i2c_debug >= level)						\
41		printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg);	\
42} while (0)
43
44#define I2C_WAIT_DELAY 32
45#define I2C_WAIT_RETRY 64
46
47#define I2C_EXTEND  (1 << 3)
48#define I2C_NOSTOP  (1 << 4)
49
50static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
51{
52	struct cx25821_i2c *bus = i2c_adap->algo_data;
53	struct cx25821_dev *dev = bus->dev;
54	return cx_read(bus->reg_stat) & 0x01;
55}
56
57static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
58{
59	struct cx25821_i2c *bus = i2c_adap->algo_data;
60	struct cx25821_dev *dev = bus->dev;
61	return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
62}
63
64static int i2c_wait_done(struct i2c_adapter *i2c_adap)
65{
66	int count;
67
68	for (count = 0; count < I2C_WAIT_RETRY; count++) {
69		if (!i2c_is_busy(i2c_adap))
70			break;
71		udelay(I2C_WAIT_DELAY);
72	}
73
74	if (I2C_WAIT_RETRY == count)
75		return 0;
76
77	return 1;
78}
79
80static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
81			 const struct i2c_msg *msg, int joined_rlen)
82{
83	struct cx25821_i2c *bus = i2c_adap->algo_data;
84	struct cx25821_dev *dev = bus->dev;
85	u32 wdata, addr, ctrl;
86	int retval, cnt;
87
88	if (joined_rlen)
89		dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
90			msg->len, joined_rlen);
91	else
92		dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);
93
94	/* Deal with i2c probe functions with zero payload */
95	if (msg->len == 0) {
96		cx_write(bus->reg_addr, msg->addr << 25);
97		cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
98
99		if (!i2c_wait_done(i2c_adap))
100			return -EIO;
101
102		if (!i2c_slave_did_ack(i2c_adap))
103			return -EIO;
104
105		dprintk(1, "%s(): returns 0\n", __func__);
106		return 0;
107	}
108
109	/* dev, reg + first byte */
110	addr = (msg->addr << 25) | msg->buf[0];
111	wdata = msg->buf[0];
112
113	ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
114
115	if (msg->len > 1)
116		ctrl |= I2C_NOSTOP | I2C_EXTEND;
117	else if (joined_rlen)
118		ctrl |= I2C_NOSTOP;
119
120	cx_write(bus->reg_addr, addr);
121	cx_write(bus->reg_wdata, wdata);
122	cx_write(bus->reg_ctrl, ctrl);
123
124	retval = i2c_wait_done(i2c_adap);
125	if (retval < 0)
126		goto err;
127
128	if (retval == 0)
129		goto eio;
130
131	if (i2c_debug) {
132		if (!(ctrl & I2C_NOSTOP))
133			printk(" >\n");
134	}
135
136	for (cnt = 1; cnt < msg->len; cnt++) {
137		/* following bytes */
138		wdata = msg->buf[cnt];
139		ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
140
141		if (cnt < msg->len - 1)
142			ctrl |= I2C_NOSTOP | I2C_EXTEND;
143		else if (joined_rlen)
144			ctrl |= I2C_NOSTOP;
145
146		cx_write(bus->reg_addr, addr);
147		cx_write(bus->reg_wdata, wdata);
148		cx_write(bus->reg_ctrl, ctrl);
149
150		retval = i2c_wait_done(i2c_adap);
151		if (retval < 0)
152			goto err;
153
154		if (retval == 0)
155			goto eio;
156
157		if (i2c_debug) {
158			dprintk(1, " %02x", msg->buf[cnt]);
159			if (!(ctrl & I2C_NOSTOP))
160				dprintk(1, " >\n");
161		}
162	}
163
164	return msg->len;
165
166eio:
167	retval = -EIO;
168err:
169	if (i2c_debug)
170		pr_err(" ERR: %d\n", retval);
171	return retval;
172}
173
174static int i2c_readbytes(struct i2c_adapter *i2c_adap,
175			 const struct i2c_msg *msg, int joined)
176{
177	struct cx25821_i2c *bus = i2c_adap->algo_data;
178	struct cx25821_dev *dev = bus->dev;
179	u32 ctrl, cnt;
180	int retval;
181
182	if (i2c_debug && !joined)
183		dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);
184
185	/* Deal with i2c probe functions with zero payload */
186	if (msg->len == 0) {
187		cx_write(bus->reg_addr, msg->addr << 25);
188		cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
189		if (!i2c_wait_done(i2c_adap))
190			return -EIO;
191		if (!i2c_slave_did_ack(i2c_adap))
192			return -EIO;
193
194		dprintk(1, "%s(): returns 0\n", __func__);
195		return 0;
196	}
197
198	if (i2c_debug) {
199		if (joined)
200			dprintk(1, " R");
201		else
202			dprintk(1, " <R %02x", (msg->addr << 1) + 1);
203	}
204
205	for (cnt = 0; cnt < msg->len; cnt++) {
206
207		ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;
208
209		if (cnt < msg->len - 1)
210			ctrl |= I2C_NOSTOP | I2C_EXTEND;
211
212		cx_write(bus->reg_addr, msg->addr << 25);
213		cx_write(bus->reg_ctrl, ctrl);
214
215		retval = i2c_wait_done(i2c_adap);
216		if (retval < 0)
217			goto err;
218		if (retval == 0)
219			goto eio;
220		msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
221
222		if (i2c_debug) {
223			dprintk(1, " %02x", msg->buf[cnt]);
224			if (!(ctrl & I2C_NOSTOP))
225				dprintk(1, " >\n");
226		}
227	}
228
229	return msg->len;
230eio:
231	retval = -EIO;
232err:
233	if (i2c_debug)
234		pr_err(" ERR: %d\n", retval);
235	return retval;
236}
237
238static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
239{
240	struct cx25821_i2c *bus = i2c_adap->algo_data;
241	struct cx25821_dev *dev = bus->dev;
242	int i, retval = 0;
243
244	dprintk(1, "%s(num = %d)\n", __func__, num);
245
246	for (i = 0; i < num; i++) {
247		dprintk(1, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
248			__func__, num, msgs[i].addr, msgs[i].len);
249
250		if (msgs[i].flags & I2C_M_RD) {
251			/* read */
252			retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
253		} else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
254			   msgs[i].addr == msgs[i + 1].addr) {
255			/* write then read from same address */
256			retval = i2c_sendbytes(i2c_adap, &msgs[i],
257					msgs[i + 1].len);
258
259			if (retval < 0)
260				goto err;
261			i++;
262			retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
263		} else {
264			/* write */
265			retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
266		}
267
268		if (retval < 0)
269			goto err;
270	}
271	return num;
272
273err:
274	return retval;
275}
276
277
278static u32 cx25821_functionality(struct i2c_adapter *adap)
279{
280	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WORD_DATA |
281		I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
282}
283
284static struct i2c_algorithm cx25821_i2c_algo_template = {
285	.master_xfer = i2c_xfer,
286	.functionality = cx25821_functionality,
287#ifdef NEED_ALGO_CONTROL
288	.algo_control = dummy_algo_control,
289#endif
290};
291
292static struct i2c_adapter cx25821_i2c_adap_template = {
293	.name = "cx25821",
294	.owner = THIS_MODULE,
295	.algo = &cx25821_i2c_algo_template,
296};
297
298static struct i2c_client cx25821_i2c_client_template = {
299	.name = "cx25821 internal",
300};
301
302/* init + register i2c adapter */
303int cx25821_i2c_register(struct cx25821_i2c *bus)
304{
305	struct cx25821_dev *dev = bus->dev;
306
307	dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);
308
309	bus->i2c_adap = cx25821_i2c_adap_template;
310	bus->i2c_client = cx25821_i2c_client_template;
311	bus->i2c_adap.dev.parent = &dev->pci->dev;
312
313	strlcpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));
314
315	bus->i2c_adap.algo_data = bus;
316	i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
317	i2c_add_adapter(&bus->i2c_adap);
318
319	bus->i2c_client.adapter = &bus->i2c_adap;
320
321	/* set up the I2c */
322	bus->i2c_client.addr = (0x88 >> 1);
323
324	return bus->i2c_rc;
325}
326
327int cx25821_i2c_unregister(struct cx25821_i2c *bus)
328{
329	i2c_del_adapter(&bus->i2c_adap);
330	return 0;
331}
332
333#if 0 /* Currently unused */
334static void cx25821_av_clk(struct cx25821_dev *dev, int enable)
335{
336	/* write 0 to bus 2 addr 0x144 via i2x_xfer() */
337	char buffer[3];
338	struct i2c_msg msg;
339	dprintk(1, "%s(enabled = %d)\n", __func__, enable);
340
341	/* Register 0x144 */
342	buffer[0] = 0x01;
343	buffer[1] = 0x44;
344	if (enable == 1)
345		buffer[2] = 0x05;
346	else
347		buffer[2] = 0x00;
348
349	msg.addr = 0x44;
350	msg.flags = I2C_M_TEN;
351	msg.len = 3;
352	msg.buf = buffer;
353
354	i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
355}
356#endif
357
358int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
359{
360	struct i2c_client *client = &bus->i2c_client;
361	int v = 0;
362	u8 addr[2] = { 0, 0 };
363	u8 buf[4] = { 0, 0, 0, 0 };
364
365	struct i2c_msg msgs[2] = {
366		{
367			.addr = client->addr,
368			.flags = 0,
369			.len = 2,
370			.buf = addr,
371		}, {
372			.addr = client->addr,
373			.flags = I2C_M_RD,
374			.len = 4,
375			.buf = buf,
376		}
377	};
378
379	addr[0] = (reg_addr >> 8);
380	addr[1] = (reg_addr & 0xff);
381	msgs[0].addr = 0x44;
382	msgs[1].addr = 0x44;
383
384	i2c_xfer(client->adapter, msgs, 2);
385
386	v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
387	*value = v;
388
389	return v;
390}
391
392int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
393{
394	struct i2c_client *client = &bus->i2c_client;
395	int retval = 0;
396	u8 buf[6] = { 0, 0, 0, 0, 0, 0 };
397
398	struct i2c_msg msgs[1] = {
399		{
400			.addr = client->addr,
401			.flags = 0,
402			.len = 6,
403			.buf = buf,
404		}
405	};
406
407	buf[0] = reg_addr >> 8;
408	buf[1] = reg_addr & 0xff;
409	buf[5] = (value >> 24) & 0xff;
410	buf[4] = (value >> 16) & 0xff;
411	buf[3] = (value >> 8) & 0xff;
412	buf[2] = value & 0xff;
413	client->flags = 0;
414	msgs[0].addr = 0x44;
415
416	retval = i2c_xfer(client->adapter, msgs, 1);
417
418	return retval;
419}
420