1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Driver for the Auvitek AU0828 USB bridge
4  *
5  *  Copyright (c) 2008 Steven Toth <stoth@linuxtv.org>
6  */
7 
8 #include "au0828.h"
9 
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/init.h>
13 #include <linux/delay.h>
14 #include <linux/io.h>
15 
16 #include "media/tuner.h"
17 #include <media/v4l2-common.h>
18 
19 static int i2c_scan;
20 module_param(i2c_scan, int, 0444);
21 MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
22 
23 #define I2C_WAIT_DELAY 25
24 #define I2C_WAIT_RETRY 1000
25 
26 static inline int i2c_slave_did_read_ack(struct i2c_adapter *i2c_adap)
27 {
28 	struct au0828_dev *dev = i2c_adap->algo_data;
29 	return au0828_read(dev, AU0828_I2C_STATUS_201) &
30 		AU0828_I2C_STATUS_NO_READ_ACK ? 0 : 1;
31 }
32 
33 static int i2c_wait_read_ack(struct i2c_adapter *i2c_adap)
34 {
35 	int count;
36 
37 	for (count = 0; count < I2C_WAIT_RETRY; count++) {
38 		if (!i2c_slave_did_read_ack(i2c_adap))
39 			break;
40 		udelay(I2C_WAIT_DELAY);
41 	}
42 
43 	if (I2C_WAIT_RETRY == count)
44 		return 0;
45 
46 	return 1;
47 }
48 
49 static inline int i2c_is_read_busy(struct i2c_adapter *i2c_adap)
50 {
51 	struct au0828_dev *dev = i2c_adap->algo_data;
52 	return au0828_read(dev, AU0828_I2C_STATUS_201) &
53 		AU0828_I2C_STATUS_READ_DONE ? 0 : 1;
54 }
55 
56 static int i2c_wait_read_done(struct i2c_adapter *i2c_adap)
57 {
58 	int count;
59 
60 	for (count = 0; count < I2C_WAIT_RETRY; count++) {
61 		if (!i2c_is_read_busy(i2c_adap))
62 			break;
63 		udelay(I2C_WAIT_DELAY);
64 	}
65 
66 	if (I2C_WAIT_RETRY == count)
67 		return 0;
68 
69 	return 1;
70 }
71 
72 static inline int i2c_is_write_done(struct i2c_adapter *i2c_adap)
73 {
74 	struct au0828_dev *dev = i2c_adap->algo_data;
75 	return au0828_read(dev, AU0828_I2C_STATUS_201) &
76 		AU0828_I2C_STATUS_WRITE_DONE ? 1 : 0;
77 }
78 
79 static int i2c_wait_write_done(struct i2c_adapter *i2c_adap)
80 {
81 	int count;
82 
83 	for (count = 0; count < I2C_WAIT_RETRY; count++) {
84 		if (i2c_is_write_done(i2c_adap))
85 			break;
86 		udelay(I2C_WAIT_DELAY);
87 	}
88 
89 	if (I2C_WAIT_RETRY == count)
90 		return 0;
91 
92 	return 1;
93 }
94 
95 static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
96 {
97 	struct au0828_dev *dev = i2c_adap->algo_data;
98 	return au0828_read(dev, AU0828_I2C_STATUS_201) &
99 		AU0828_I2C_STATUS_BUSY ? 1 : 0;
100 }
101 
102 static int i2c_wait_done(struct i2c_adapter *i2c_adap)
103 {
104 	int count;
105 
106 	for (count = 0; count < I2C_WAIT_RETRY; count++) {
107 		if (!i2c_is_busy(i2c_adap))
108 			break;
109 		udelay(I2C_WAIT_DELAY);
110 	}
111 
112 	if (I2C_WAIT_RETRY == count)
113 		return 0;
114 
115 	return 1;
116 }
117 
118 /* FIXME: Implement join handling correctly */
119 static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
120 	const struct i2c_msg *msg, int joined_rlen)
121 {
122 	int i, strobe = 0;
123 	struct au0828_dev *dev = i2c_adap->algo_data;
124 	u8 i2c_speed = dev->board.i2c_clk_divider;
125 
126 	dprintk(4, "%s()\n", __func__);
127 
128 	au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
129 
130 	if (((dev->board.tuner_type == TUNER_XC5000) ||
131 	     (dev->board.tuner_type == TUNER_XC5000C)) &&
132 	    (dev->board.tuner_addr == msg->addr)) {
133 		/*
134 		 * Due to I2C clock stretch, we need to use a lower speed
135 		 * on xc5000 for commands. However, firmware transfer can
136 		 * speed up to 400 KHz.
137 		 */
138 		if (msg->len == 64)
139 			i2c_speed = AU0828_I2C_CLK_250KHZ;
140 		else
141 			i2c_speed = AU0828_I2C_CLK_20KHZ;
142 	}
143 	/* Set the I2C clock */
144 	au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202, i2c_speed);
145 
146 	/* Hardware needs 8 bit addresses */
147 	au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
148 
149 	dprintk(4, "SEND: %02x\n", msg->addr);
150 
151 	/* Deal with i2c_scan */
152 	if (msg->len == 0) {
153 		/* The analog tuner detection code makes use of the SMBUS_QUICK
154 		   message (which involves a zero length i2c write).  To avoid
155 		   checking the status register when we didn't strobe out any
156 		   actual bytes to the bus, just do a read check.  This is
157 		   consistent with how I saw i2c device checking done in the
158 		   USB trace of the Windows driver */
159 		au0828_write(dev, AU0828_I2C_TRIGGER_200,
160 			     AU0828_I2C_TRIGGER_READ);
161 
162 		if (!i2c_wait_done(i2c_adap))
163 			return -EIO;
164 
165 		if (i2c_wait_read_ack(i2c_adap))
166 			return -EIO;
167 
168 		return 0;
169 	}
170 
171 	for (i = 0; i < msg->len;) {
172 
173 		dprintk(4, " %02x\n", msg->buf[i]);
174 
175 		au0828_write(dev, AU0828_I2C_WRITE_FIFO_205, msg->buf[i]);
176 
177 		strobe++;
178 		i++;
179 
180 		if ((strobe >= 4) || (i >= msg->len)) {
181 
182 			/* Strobe the byte into the bus */
183 			if (i < msg->len)
184 				au0828_write(dev, AU0828_I2C_TRIGGER_200,
185 					     AU0828_I2C_TRIGGER_WRITE |
186 					     AU0828_I2C_TRIGGER_HOLD);
187 			else
188 				au0828_write(dev, AU0828_I2C_TRIGGER_200,
189 					     AU0828_I2C_TRIGGER_WRITE);
190 
191 			/* Reset strobe trigger */
192 			strobe = 0;
193 
194 			if (!i2c_wait_write_done(i2c_adap))
195 				return -EIO;
196 
197 		}
198 
199 	}
200 	if (!i2c_wait_done(i2c_adap))
201 		return -EIO;
202 
203 	dprintk(4, "\n");
204 
205 	return msg->len;
206 }
207 
208 /* FIXME: Implement join handling correctly */
209 static int i2c_readbytes(struct i2c_adapter *i2c_adap,
210 	const struct i2c_msg *msg, int joined)
211 {
212 	struct au0828_dev *dev = i2c_adap->algo_data;
213 	u8 i2c_speed = dev->board.i2c_clk_divider;
214 	int i;
215 
216 	dprintk(4, "%s()\n", __func__);
217 
218 	au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
219 
220 	/*
221 	 * Due to xc5000c clock stretch, we cannot use full speed at
222 	 * readings from xc5000, as otherwise they'll fail.
223 	 */
224 	if (((dev->board.tuner_type == TUNER_XC5000) ||
225 	     (dev->board.tuner_type == TUNER_XC5000C)) &&
226 	    (dev->board.tuner_addr == msg->addr))
227 		i2c_speed = AU0828_I2C_CLK_20KHZ;
228 
229 	/* Set the I2C clock */
230 	au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202, i2c_speed);
231 
232 	/* Hardware needs 8 bit addresses */
233 	au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
234 
235 	dprintk(4, " RECV:\n");
236 
237 	/* Deal with i2c_scan */
238 	if (msg->len == 0) {
239 		au0828_write(dev, AU0828_I2C_TRIGGER_200,
240 			     AU0828_I2C_TRIGGER_READ);
241 
242 		if (i2c_wait_read_ack(i2c_adap))
243 			return -EIO;
244 		return 0;
245 	}
246 
247 	for (i = 0; i < msg->len;) {
248 
249 		i++;
250 
251 		if (i < msg->len)
252 			au0828_write(dev, AU0828_I2C_TRIGGER_200,
253 				     AU0828_I2C_TRIGGER_READ |
254 				     AU0828_I2C_TRIGGER_HOLD);
255 		else
256 			au0828_write(dev, AU0828_I2C_TRIGGER_200,
257 				     AU0828_I2C_TRIGGER_READ);
258 
259 		if (!i2c_wait_read_done(i2c_adap))
260 			return -EIO;
261 
262 		msg->buf[i-1] = au0828_read(dev, AU0828_I2C_READ_FIFO_209) &
263 			0xff;
264 
265 		dprintk(4, " %02x\n", msg->buf[i-1]);
266 	}
267 	if (!i2c_wait_done(i2c_adap))
268 		return -EIO;
269 
270 	dprintk(4, "\n");
271 
272 	return msg->len;
273 }
274 
275 static int i2c_xfer(struct i2c_adapter *i2c_adap,
276 		    struct i2c_msg *msgs, int num)
277 {
278 	int i, retval = 0;
279 
280 	dprintk(4, "%s(num = %d)\n", __func__, num);
281 
282 	for (i = 0; i < num; i++) {
283 		dprintk(4, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
284 			__func__, num, msgs[i].addr, msgs[i].len);
285 		if (msgs[i].flags & I2C_M_RD) {
286 			/* read */
287 			retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
288 		} else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
289 			   msgs[i].addr == msgs[i + 1].addr) {
290 			/* write then read from same address */
291 			retval = i2c_sendbytes(i2c_adap, &msgs[i],
292 					       msgs[i + 1].len);
293 			if (retval < 0)
294 				goto err;
295 			i++;
296 			retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
297 		} else {
298 			/* write */
299 			retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
300 		}
301 		if (retval < 0)
302 			goto err;
303 	}
304 	return num;
305 
306 err:
307 	return retval;
308 }
309 
310 static u32 au0828_functionality(struct i2c_adapter *adap)
311 {
312 	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
313 }
314 
315 static const struct i2c_algorithm au0828_i2c_algo_template = {
316 	.master_xfer	= i2c_xfer,
317 	.functionality	= au0828_functionality,
318 };
319 
320 /* ----------------------------------------------------------------------- */
321 
322 static const struct i2c_adapter au0828_i2c_adap_template = {
323 	.name              = KBUILD_MODNAME,
324 	.owner             = THIS_MODULE,
325 	.algo              = &au0828_i2c_algo_template,
326 };
327 
328 static const struct i2c_client au0828_i2c_client_template = {
329 	.name	= "au0828 internal",
330 };
331 
332 static char *i2c_devs[128] = {
333 	[0x8e >> 1] = "au8522",
334 	[0xa0 >> 1] = "eeprom",
335 	[0xc2 >> 1] = "tuner/xc5000",
336 };
337 
338 static void do_i2c_scan(char *name, struct i2c_client *c)
339 {
340 	unsigned char buf;
341 	int i, rc;
342 
343 	for (i = 0; i < 128; i++) {
344 		c->addr = i;
345 		rc = i2c_master_recv(c, &buf, 0);
346 		if (rc < 0)
347 			continue;
348 		pr_info("%s: i2c scan: found device @ 0x%x  [%s]\n",
349 		       name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
350 	}
351 }
352 
353 /* init + register i2c adapter */
354 int au0828_i2c_register(struct au0828_dev *dev)
355 {
356 	dprintk(1, "%s()\n", __func__);
357 
358 	dev->i2c_adap = au0828_i2c_adap_template;
359 	dev->i2c_algo = au0828_i2c_algo_template;
360 	dev->i2c_client = au0828_i2c_client_template;
361 
362 	dev->i2c_adap.dev.parent = &dev->usbdev->dev;
363 
364 	strscpy(dev->i2c_adap.name, KBUILD_MODNAME,
365 		sizeof(dev->i2c_adap.name));
366 
367 	dev->i2c_adap.algo = &dev->i2c_algo;
368 	dev->i2c_adap.algo_data = dev;
369 #ifdef CONFIG_VIDEO_AU0828_V4L2
370 	i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
371 #else
372 	i2c_set_adapdata(&dev->i2c_adap, dev);
373 #endif
374 	i2c_add_adapter(&dev->i2c_adap);
375 
376 	dev->i2c_client.adapter = &dev->i2c_adap;
377 
378 	if (0 == dev->i2c_rc) {
379 		pr_info("i2c bus registered\n");
380 		if (i2c_scan)
381 			do_i2c_scan(KBUILD_MODNAME, &dev->i2c_client);
382 	} else
383 		pr_info("i2c bus register FAILED\n");
384 
385 	return dev->i2c_rc;
386 }
387 
388 int au0828_i2c_unregister(struct au0828_dev *dev)
389 {
390 	i2c_del_adapter(&dev->i2c_adap);
391 	return 0;
392 }
393 
394