1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Driver for the Conexant CX25821 PCIe bridge
4 *
5 *  Copyright (C) 2009 Conexant Systems Inc.
6 *  Authors  <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
7 *	Based on Steven Toth <stoth@linuxtv.org> cx23885 driver
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/module.h>
13#include <linux/i2c.h>
14#include "cx25821.h"
15
16static unsigned int i2c_debug;
17module_param(i2c_debug, int, 0644);
18MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
19
20static unsigned int i2c_scan;
21module_param(i2c_scan, int, 0444);
22MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
23
24#define dprintk(level, fmt, arg...)					\
25do {									\
26	if (i2c_debug >= level)						\
27		printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg);	\
28} while (0)
29
30#define I2C_WAIT_DELAY 32
31#define I2C_WAIT_RETRY 64
32
33#define I2C_EXTEND  (1 << 3)
34#define I2C_NOSTOP  (1 << 4)
35
36static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
37{
38	struct cx25821_i2c *bus = i2c_adap->algo_data;
39	struct cx25821_dev *dev = bus->dev;
40	return cx_read(bus->reg_stat) & 0x01;
41}
42
43static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
44{
45	struct cx25821_i2c *bus = i2c_adap->algo_data;
46	struct cx25821_dev *dev = bus->dev;
47	return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
48}
49
50static int i2c_wait_done(struct i2c_adapter *i2c_adap)
51{
52	int count;
53
54	for (count = 0; count < I2C_WAIT_RETRY; count++) {
55		if (!i2c_is_busy(i2c_adap))
56			break;
57		udelay(I2C_WAIT_DELAY);
58	}
59
60	if (I2C_WAIT_RETRY == count)
61		return 0;
62
63	return 1;
64}
65
66static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
67			 const struct i2c_msg *msg, int joined_rlen)
68{
69	struct cx25821_i2c *bus = i2c_adap->algo_data;
70	struct cx25821_dev *dev = bus->dev;
71	u32 wdata, addr, ctrl;
72	int retval, cnt;
73
74	if (joined_rlen)
75		dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
76			msg->len, joined_rlen);
77	else
78		dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);
79
80	/* Deal with i2c probe functions with zero payload */
81	if (msg->len == 0) {
82		cx_write(bus->reg_addr, msg->addr << 25);
83		cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
84
85		if (!i2c_wait_done(i2c_adap))
86			return -EIO;
87
88		if (!i2c_slave_did_ack(i2c_adap))
89			return -EIO;
90
91		dprintk(1, "%s(): returns 0\n", __func__);
92		return 0;
93	}
94
95	/* dev, reg + first byte */
96	addr = (msg->addr << 25) | msg->buf[0];
97	wdata = msg->buf[0];
98
99	ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
100
101	if (msg->len > 1)
102		ctrl |= I2C_NOSTOP | I2C_EXTEND;
103	else if (joined_rlen)
104		ctrl |= I2C_NOSTOP;
105
106	cx_write(bus->reg_addr, addr);
107	cx_write(bus->reg_wdata, wdata);
108	cx_write(bus->reg_ctrl, ctrl);
109
110	retval = i2c_wait_done(i2c_adap);
111	if (retval < 0)
112		goto err;
113
114	if (retval == 0)
115		goto eio;
116
117	if (i2c_debug) {
118		if (!(ctrl & I2C_NOSTOP))
119			printk(" >\n");
120	}
121
122	for (cnt = 1; cnt < msg->len; cnt++) {
123		/* following bytes */
124		wdata = msg->buf[cnt];
125		ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
126
127		if (cnt < msg->len - 1)
128			ctrl |= I2C_NOSTOP | I2C_EXTEND;
129		else if (joined_rlen)
130			ctrl |= I2C_NOSTOP;
131
132		cx_write(bus->reg_addr, addr);
133		cx_write(bus->reg_wdata, wdata);
134		cx_write(bus->reg_ctrl, ctrl);
135
136		retval = i2c_wait_done(i2c_adap);
137		if (retval < 0)
138			goto err;
139
140		if (retval == 0)
141			goto eio;
142
143		if (i2c_debug) {
144			dprintk(1, " %02x", msg->buf[cnt]);
145			if (!(ctrl & I2C_NOSTOP))
146				dprintk(1, " >\n");
147		}
148	}
149
150	return msg->len;
151
152eio:
153	retval = -EIO;
154err:
155	if (i2c_debug)
156		pr_err(" ERR: %d\n", retval);
157	return retval;
158}
159
160static int i2c_readbytes(struct i2c_adapter *i2c_adap,
161			 const struct i2c_msg *msg, int joined)
162{
163	struct cx25821_i2c *bus = i2c_adap->algo_data;
164	struct cx25821_dev *dev = bus->dev;
165	u32 ctrl, cnt;
166	int retval;
167
168	if (i2c_debug && !joined)
169		dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);
170
171	/* Deal with i2c probe functions with zero payload */
172	if (msg->len == 0) {
173		cx_write(bus->reg_addr, msg->addr << 25);
174		cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
175		if (!i2c_wait_done(i2c_adap))
176			return -EIO;
177		if (!i2c_slave_did_ack(i2c_adap))
178			return -EIO;
179
180		dprintk(1, "%s(): returns 0\n", __func__);
181		return 0;
182	}
183
184	if (i2c_debug) {
185		if (joined)
186			dprintk(1, " R");
187		else
188			dprintk(1, " <R %02x", (msg->addr << 1) + 1);
189	}
190
191	for (cnt = 0; cnt < msg->len; cnt++) {
192
193		ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;
194
195		if (cnt < msg->len - 1)
196			ctrl |= I2C_NOSTOP | I2C_EXTEND;
197
198		cx_write(bus->reg_addr, msg->addr << 25);
199		cx_write(bus->reg_ctrl, ctrl);
200
201		retval = i2c_wait_done(i2c_adap);
202		if (retval < 0)
203			goto err;
204		if (retval == 0)
205			goto eio;
206		msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
207
208		if (i2c_debug) {
209			dprintk(1, " %02x", msg->buf[cnt]);
210			if (!(ctrl & I2C_NOSTOP))
211				dprintk(1, " >\n");
212		}
213	}
214
215	return msg->len;
216eio:
217	retval = -EIO;
218err:
219	if (i2c_debug)
220		pr_err(" ERR: %d\n", retval);
221	return retval;
222}
223
224static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
225{
226	struct cx25821_i2c *bus = i2c_adap->algo_data;
227	struct cx25821_dev *dev = bus->dev;
228	int i, retval = 0;
229
230	dprintk(1, "%s(num = %d)\n", __func__, num);
231
232	for (i = 0; i < num; i++) {
233		dprintk(1, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
234			__func__, num, msgs[i].addr, msgs[i].len);
235
236		if (msgs[i].flags & I2C_M_RD) {
237			/* read */
238			retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
239		} else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
240			   msgs[i].addr == msgs[i + 1].addr) {
241			/* write then read from same address */
242			retval = i2c_sendbytes(i2c_adap, &msgs[i],
243					msgs[i + 1].len);
244
245			if (retval < 0)
246				goto err;
247			i++;
248			retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
249		} else {
250			/* write */
251			retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
252		}
253
254		if (retval < 0)
255			goto err;
256	}
257	return num;
258
259err:
260	return retval;
261}
262
263
264static u32 cx25821_functionality(struct i2c_adapter *adap)
265{
266	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WORD_DATA |
267		I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
268}
269
270static const struct i2c_algorithm cx25821_i2c_algo_template = {
271	.master_xfer = i2c_xfer,
272	.functionality = cx25821_functionality,
273#ifdef NEED_ALGO_CONTROL
274	.algo_control = dummy_algo_control,
275#endif
276};
277
278static const struct i2c_adapter cx25821_i2c_adap_template = {
279	.name = "cx25821",
280	.owner = THIS_MODULE,
281	.algo = &cx25821_i2c_algo_template,
282};
283
284static const struct i2c_client cx25821_i2c_client_template = {
285	.name = "cx25821 internal",
286};
287
288/* init + register i2c adapter */
289int cx25821_i2c_register(struct cx25821_i2c *bus)
290{
291	struct cx25821_dev *dev = bus->dev;
292
293	dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);
294
295	bus->i2c_adap = cx25821_i2c_adap_template;
296	bus->i2c_client = cx25821_i2c_client_template;
297	bus->i2c_adap.dev.parent = &dev->pci->dev;
298
299	strscpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));
300
301	bus->i2c_adap.algo_data = bus;
302	i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
303	i2c_add_adapter(&bus->i2c_adap);
304
305	bus->i2c_client.adapter = &bus->i2c_adap;
306
307	/* set up the I2c */
308	bus->i2c_client.addr = (0x88 >> 1);
309
310	return bus->i2c_rc;
311}
312
313int cx25821_i2c_unregister(struct cx25821_i2c *bus)
314{
315	i2c_del_adapter(&bus->i2c_adap);
316	return 0;
317}
318
319#if 0 /* Currently unused */
320static void cx25821_av_clk(struct cx25821_dev *dev, int enable)
321{
322	/* write 0 to bus 2 addr 0x144 via i2x_xfer() */
323	char buffer[3];
324	struct i2c_msg msg;
325	dprintk(1, "%s(enabled = %d)\n", __func__, enable);
326
327	/* Register 0x144 */
328	buffer[0] = 0x01;
329	buffer[1] = 0x44;
330	if (enable == 1)
331		buffer[2] = 0x05;
332	else
333		buffer[2] = 0x00;
334
335	msg.addr = 0x44;
336	msg.flags = I2C_M_TEN;
337	msg.len = 3;
338	msg.buf = buffer;
339
340	i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
341}
342#endif
343
344int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
345{
346	struct i2c_client *client = &bus->i2c_client;
347	int v = 0;
348	u8 addr[2] = { 0, 0 };
349	u8 buf[4] = { 0, 0, 0, 0 };
350
351	struct i2c_msg msgs[2] = {
352		{
353			.addr = client->addr,
354			.flags = 0,
355			.len = 2,
356			.buf = addr,
357		}, {
358			.addr = client->addr,
359			.flags = I2C_M_RD,
360			.len = 4,
361			.buf = buf,
362		}
363	};
364
365	addr[0] = (reg_addr >> 8);
366	addr[1] = (reg_addr & 0xff);
367	msgs[0].addr = 0x44;
368	msgs[1].addr = 0x44;
369
370	i2c_xfer(client->adapter, msgs, 2);
371
372	v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
373	*value = v;
374
375	return v;
376}
377
378int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
379{
380	struct i2c_client *client = &bus->i2c_client;
381	int retval = 0;
382	u8 buf[6] = { 0, 0, 0, 0, 0, 0 };
383
384	struct i2c_msg msgs[1] = {
385		{
386			.addr = client->addr,
387			.flags = 0,
388			.len = 6,
389			.buf = buf,
390		}
391	};
392
393	buf[0] = reg_addr >> 8;
394	buf[1] = reg_addr & 0xff;
395	buf[5] = (value >> 24) & 0xff;
396	buf[4] = (value >> 16) & 0xff;
397	buf[3] = (value >> 8) & 0xff;
398	buf[2] = value & 0xff;
399	client->flags = 0;
400	msgs[0].addr = 0x44;
401
402	retval = i2c_xfer(client->adapter, msgs, 1);
403
404	return retval;
405}
406