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 
16 static unsigned int i2c_debug;
17 module_param(i2c_debug, int, 0644);
18 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
19 
20 static unsigned int i2c_scan;
21 module_param(i2c_scan, int, 0444);
22 MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
23 
24 #define dprintk(level, fmt, arg...)					\
25 do {									\
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 
i2c_slave_did_ack(struct i2c_adapter * i2c_adap)36 static 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 
i2c_is_busy(struct i2c_adapter * i2c_adap)43 static 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 
i2c_wait_done(struct i2c_adapter * i2c_adap)50 static 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 
i2c_sendbytes(struct i2c_adapter * i2c_adap,const struct i2c_msg * msg,int joined_rlen)66 static 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 
152 eio:
153 	retval = -EIO;
154 err:
155 	if (i2c_debug)
156 		pr_err(" ERR: %d\n", retval);
157 	return retval;
158 }
159 
i2c_readbytes(struct i2c_adapter * i2c_adap,const struct i2c_msg * msg,int joined)160 static 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;
216 eio:
217 	retval = -EIO;
218 err:
219 	if (i2c_debug)
220 		pr_err(" ERR: %d\n", retval);
221 	return retval;
222 }
223 
i2c_xfer(struct i2c_adapter * i2c_adap,struct i2c_msg * msgs,int num)224 static 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 
259 err:
260 	return retval;
261 }
262 
263 
cx25821_functionality(struct i2c_adapter * adap)264 static 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 
270 static 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 
278 static const struct i2c_adapter cx25821_i2c_adap_template = {
279 	.name = "cx25821",
280 	.owner = THIS_MODULE,
281 	.algo = &cx25821_i2c_algo_template,
282 };
283 
284 static const struct i2c_client cx25821_i2c_client_template = {
285 	.name = "cx25821 internal",
286 };
287 
288 /* init + register i2c adapter */
cx25821_i2c_register(struct cx25821_i2c * bus)289 int 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 
cx25821_i2c_unregister(struct cx25821_i2c * bus)313 int 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 */
320 static 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 
cx25821_i2c_read(struct cx25821_i2c * bus,u16 reg_addr,int * value)344 int 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 
cx25821_i2c_write(struct cx25821_i2c * bus,u16 reg_addr,int value)378 int 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