Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
3d438291 | 2 | * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters |
1da177e4 | 3 | * Copyright (C) 2004 Arcom Control Systems |
c01b0831 | 4 | * Copyright (C) 2008 Pengutronix |
1da177e4 LT |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
1da177e4 LT |
15 | */ |
16 | ||
17 | #include <linux/kernel.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/moduleparam.h> | |
20 | #include <linux/delay.h> | |
8e99ada8 | 21 | #include <linux/jiffies.h> |
1da177e4 LT |
22 | #include <linux/errno.h> |
23 | #include <linux/i2c.h> | |
24 | #include <linux/i2c-algo-pca.h> | |
1da177e4 | 25 | |
bac3e7c2 FS |
26 | #define DEB1(fmt, args...) do { if (i2c_debug >= 1) \ |
27 | printk(KERN_DEBUG fmt, ## args); } while (0) | |
28 | #define DEB2(fmt, args...) do { if (i2c_debug >= 2) \ | |
29 | printk(KERN_DEBUG fmt, ## args); } while (0) | |
30 | #define DEB3(fmt, args...) do { if (i2c_debug >= 3) \ | |
31 | printk(KERN_DEBUG fmt, ## args); } while (0) | |
1da177e4 | 32 | |
60507095 | 33 | static int i2c_debug; |
1da177e4 | 34 | |
c01b0831 WS |
35 | #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val) |
36 | #define pca_inw(adap, reg) adap->read_byte(adap->data, reg) | |
1da177e4 LT |
37 | |
38 | #define pca_status(adap) pca_inw(adap, I2C_PCA_STA) | |
c01b0831 | 39 | #define pca_clock(adap) adap->i2c_clock |
1da177e4 LT |
40 | #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val) |
41 | #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON) | |
c01b0831 | 42 | #define pca_wait(adap) adap->wait_for_completion(adap->data) |
1da177e4 | 43 | |
a76e7c68 | 44 | static void pca_reset(struct i2c_algo_pca_data *adap) |
eff9ec95 | 45 | { |
a76e7c68 TK |
46 | if (adap->chip == I2C_PCA_CHIP_9665) { |
47 | /* Ignore the reset function from the module, | |
48 | * we can use the parallel bus reset. | |
49 | */ | |
50 | pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET); | |
51 | pca_outw(adap, I2C_PCA_IND, 0xA5); | |
52 | pca_outw(adap, I2C_PCA_IND, 0x5A); | |
53 | } else { | |
54 | adap->reset_chip(adap->data); | |
55 | } | |
eff9ec95 MAC |
56 | } |
57 | ||
1da177e4 LT |
58 | /* |
59 | * Generate a start condition on the i2c bus. | |
60 | * | |
44bbe87e | 61 | * returns after the start condition has occurred |
1da177e4 | 62 | */ |
2378bc09 | 63 | static int pca_start(struct i2c_algo_pca_data *adap) |
1da177e4 LT |
64 | { |
65 | int sta = pca_get_con(adap); | |
66 | DEB2("=== START\n"); | |
67 | sta |= I2C_PCA_CON_STA; | |
68 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); | |
69 | pca_set_con(adap, sta); | |
2378bc09 | 70 | return pca_wait(adap); |
1da177e4 LT |
71 | } |
72 | ||
73 | /* | |
46b615f4 | 74 | * Generate a repeated start condition on the i2c bus |
1da177e4 | 75 | * |
44bbe87e | 76 | * return after the repeated start condition has occurred |
1da177e4 | 77 | */ |
2378bc09 | 78 | static int pca_repeated_start(struct i2c_algo_pca_data *adap) |
1da177e4 LT |
79 | { |
80 | int sta = pca_get_con(adap); | |
81 | DEB2("=== REPEATED START\n"); | |
82 | sta |= I2C_PCA_CON_STA; | |
83 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); | |
84 | pca_set_con(adap, sta); | |
2378bc09 | 85 | return pca_wait(adap); |
1da177e4 LT |
86 | } |
87 | ||
88 | /* | |
89 | * Generate a stop condition on the i2c bus | |
90 | * | |
91 | * returns after the stop condition has been generated | |
92 | * | |
93 | * STOPs do not generate an interrupt or set the SI flag, since the | |
46b615f4 | 94 | * part returns the idle state (0xf8). Hence we don't need to |
1da177e4 LT |
95 | * pca_wait here. |
96 | */ | |
97 | static void pca_stop(struct i2c_algo_pca_data *adap) | |
98 | { | |
99 | int sta = pca_get_con(adap); | |
100 | DEB2("=== STOP\n"); | |
101 | sta |= I2C_PCA_CON_STO; | |
102 | sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI); | |
103 | pca_set_con(adap, sta); | |
104 | } | |
105 | ||
106 | /* | |
107 | * Send the slave address and R/W bit | |
108 | * | |
109 | * returns after the address has been sent | |
110 | */ | |
2378bc09 | 111 | static int pca_address(struct i2c_algo_pca_data *adap, |
2086ca48 | 112 | struct i2c_msg *msg) |
1da177e4 LT |
113 | { |
114 | int sta = pca_get_con(adap); | |
ac6d5298 | 115 | int addr = i2c_8bit_addr_from_msg(msg); |
1da177e4 | 116 | |
3d438291 | 117 | DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n", |
1da177e4 | 118 | msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr); |
3d438291 | 119 | |
1da177e4 LT |
120 | pca_outw(adap, I2C_PCA_DAT, addr); |
121 | ||
122 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); | |
123 | pca_set_con(adap, sta); | |
124 | ||
2378bc09 | 125 | return pca_wait(adap); |
1da177e4 LT |
126 | } |
127 | ||
128 | /* | |
129 | * Transmit a byte. | |
130 | * | |
131 | * Returns after the byte has been transmitted | |
132 | */ | |
2378bc09 | 133 | static int pca_tx_byte(struct i2c_algo_pca_data *adap, |
2086ca48 | 134 | __u8 b) |
1da177e4 LT |
135 | { |
136 | int sta = pca_get_con(adap); | |
137 | DEB2("=== WRITE %#04x\n", b); | |
138 | pca_outw(adap, I2C_PCA_DAT, b); | |
139 | ||
140 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); | |
141 | pca_set_con(adap, sta); | |
142 | ||
2378bc09 | 143 | return pca_wait(adap); |
1da177e4 LT |
144 | } |
145 | ||
146 | /* | |
147 | * Receive a byte | |
148 | * | |
149 | * returns immediately. | |
150 | */ | |
3d438291 | 151 | static void pca_rx_byte(struct i2c_algo_pca_data *adap, |
1da177e4 LT |
152 | __u8 *b, int ack) |
153 | { | |
154 | *b = pca_inw(adap, I2C_PCA_DAT); | |
155 | DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK"); | |
156 | } | |
157 | ||
3d438291 | 158 | /* |
1da177e4 LT |
159 | * Setup ACK or NACK for next received byte and wait for it to arrive. |
160 | * | |
161 | * Returns after next byte has arrived. | |
162 | */ | |
2378bc09 | 163 | static int pca_rx_ack(struct i2c_algo_pca_data *adap, |
2086ca48 | 164 | int ack) |
1da177e4 LT |
165 | { |
166 | int sta = pca_get_con(adap); | |
167 | ||
168 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA); | |
169 | ||
2086ca48 | 170 | if (ack) |
1da177e4 LT |
171 | sta |= I2C_PCA_CON_AA; |
172 | ||
173 | pca_set_con(adap, sta); | |
2378bc09 | 174 | return pca_wait(adap); |
1da177e4 LT |
175 | } |
176 | ||
1da177e4 | 177 | static int pca_xfer(struct i2c_adapter *i2c_adap, |
2086ca48 FH |
178 | struct i2c_msg *msgs, |
179 | int num) | |
1da177e4 | 180 | { |
2086ca48 FH |
181 | struct i2c_algo_pca_data *adap = i2c_adap->algo_data; |
182 | struct i2c_msg *msg = NULL; | |
183 | int curmsg; | |
1da177e4 LT |
184 | int numbytes = 0; |
185 | int state; | |
186 | int ret; | |
2378bc09 | 187 | int completed = 1; |
8e99ada8 WS |
188 | unsigned long timeout = jiffies + i2c_adap->timeout; |
189 | ||
c454dee2 | 190 | while ((state = pca_status(adap)) != 0xf8) { |
8e99ada8 WS |
191 | if (time_before(jiffies, timeout)) { |
192 | msleep(10); | |
193 | } else { | |
194 | dev_dbg(&i2c_adap->dev, "bus is not idle. status is " | |
195 | "%#04x\n", state); | |
4403988a | 196 | return -EBUSY; |
8e99ada8 | 197 | } |
1da177e4 LT |
198 | } |
199 | ||
200 | DEB1("{{{ XFER %d messages\n", num); | |
201 | ||
2086ca48 | 202 | if (i2c_debug >= 2) { |
1da177e4 LT |
203 | for (curmsg = 0; curmsg < num; curmsg++) { |
204 | int addr, i; | |
205 | msg = &msgs[curmsg]; | |
3d438291 | 206 | |
1da177e4 | 207 | addr = (0x7f & msg->addr) ; |
3d438291 | 208 | |
2086ca48 | 209 | if (msg->flags & I2C_M_RD) |
3d438291 | 210 | printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n", |
2086ca48 | 211 | curmsg, msg->len, addr, (addr << 1) | 1); |
1da177e4 | 212 | else { |
3d438291 | 213 | printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s", |
2086ca48 | 214 | curmsg, msg->len, addr, addr << 1, |
1da177e4 | 215 | msg->len == 0 ? "" : ", "); |
2086ca48 | 216 | for (i = 0; i < msg->len; i++) |
1da177e4 LT |
217 | printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", "); |
218 | printk("]\n"); | |
219 | } | |
220 | } | |
221 | } | |
222 | ||
223 | curmsg = 0; | |
4403988a | 224 | ret = -EIO; |
1da177e4 LT |
225 | while (curmsg < num) { |
226 | state = pca_status(adap); | |
227 | ||
228 | DEB3("STATE is 0x%02x\n", state); | |
229 | msg = &msgs[curmsg]; | |
230 | ||
231 | switch (state) { | |
232 | case 0xf8: /* On reset or stop the bus is idle */ | |
2378bc09 | 233 | completed = pca_start(adap); |
1da177e4 LT |
234 | break; |
235 | ||
236 | case 0x08: /* A START condition has been transmitted */ | |
237 | case 0x10: /* A repeated start condition has been transmitted */ | |
2378bc09 | 238 | completed = pca_address(adap, msg); |
1da177e4 | 239 | break; |
3d438291 | 240 | |
1da177e4 LT |
241 | case 0x18: /* SLA+W has been transmitted; ACK has been received */ |
242 | case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */ | |
243 | if (numbytes < msg->len) { | |
2378bc09 WS |
244 | completed = pca_tx_byte(adap, |
245 | msg->buf[numbytes]); | |
1da177e4 LT |
246 | numbytes++; |
247 | break; | |
248 | } | |
249 | curmsg++; numbytes = 0; | |
250 | if (curmsg == num) | |
251 | pca_stop(adap); | |
252 | else | |
2378bc09 | 253 | completed = pca_repeated_start(adap); |
1da177e4 LT |
254 | break; |
255 | ||
256 | case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */ | |
257 | DEB2("NOT ACK received after SLA+W\n"); | |
258 | pca_stop(adap); | |
4403988a | 259 | ret = -ENXIO; |
1da177e4 LT |
260 | goto out; |
261 | ||
262 | case 0x40: /* SLA+R has been transmitted; ACK has been received */ | |
2378bc09 | 263 | completed = pca_rx_ack(adap, msg->len > 1); |
1da177e4 LT |
264 | break; |
265 | ||
266 | case 0x50: /* Data bytes has been received; ACK has been returned */ | |
267 | if (numbytes < msg->len) { | |
268 | pca_rx_byte(adap, &msg->buf[numbytes], 1); | |
269 | numbytes++; | |
2378bc09 WS |
270 | completed = pca_rx_ack(adap, |
271 | numbytes < msg->len - 1); | |
1da177e4 LT |
272 | break; |
273 | } | |
274 | curmsg++; numbytes = 0; | |
275 | if (curmsg == num) | |
276 | pca_stop(adap); | |
277 | else | |
2378bc09 | 278 | completed = pca_repeated_start(adap); |
1da177e4 LT |
279 | break; |
280 | ||
281 | case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */ | |
282 | DEB2("NOT ACK received after SLA+R\n"); | |
283 | pca_stop(adap); | |
4403988a | 284 | ret = -ENXIO; |
1da177e4 LT |
285 | goto out; |
286 | ||
287 | case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ | |
288 | DEB2("NOT ACK received after data byte\n"); | |
2196d1cf | 289 | pca_stop(adap); |
1da177e4 LT |
290 | goto out; |
291 | ||
292 | case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ | |
293 | DEB2("Arbitration lost\n"); | |
2196d1cf EB |
294 | /* |
295 | * The PCA9564 data sheet (2006-09-01) says "A | |
296 | * START condition will be transmitted when the | |
297 | * bus becomes free (STOP or SCL and SDA high)" | |
298 | * when the STA bit is set (p. 11). | |
299 | * | |
300 | * In case this won't work, try pca_reset() | |
301 | * instead. | |
302 | */ | |
303 | pca_start(adap); | |
1da177e4 | 304 | goto out; |
3d438291 | 305 | |
1da177e4 | 306 | case 0x58: /* Data byte has been received; NOT ACK has been returned */ |
2086ca48 | 307 | if (numbytes == msg->len - 1) { |
1da177e4 LT |
308 | pca_rx_byte(adap, &msg->buf[numbytes], 0); |
309 | curmsg++; numbytes = 0; | |
310 | if (curmsg == num) | |
311 | pca_stop(adap); | |
312 | else | |
2378bc09 | 313 | completed = pca_repeated_start(adap); |
1da177e4 LT |
314 | } else { |
315 | DEB2("NOT ACK sent after data byte received. " | |
316 | "Not final byte. numbytes %d. len %d\n", | |
317 | numbytes, msg->len); | |
318 | pca_stop(adap); | |
319 | goto out; | |
320 | } | |
321 | break; | |
322 | case 0x70: /* Bus error - SDA stuck low */ | |
323 | DEB2("BUS ERROR - SDA Stuck low\n"); | |
324 | pca_reset(adap); | |
325 | goto out; | |
326 | case 0x90: /* Bus error - SCL stuck low */ | |
327 | DEB2("BUS ERROR - SCL Stuck low\n"); | |
328 | pca_reset(adap); | |
329 | goto out; | |
330 | case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */ | |
331 | DEB2("BUS ERROR - Illegal START or STOP\n"); | |
332 | pca_reset(adap); | |
333 | goto out; | |
334 | default: | |
c01b0831 | 335 | dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state); |
1da177e4 LT |
336 | break; |
337 | } | |
3d438291 | 338 | |
2378bc09 WS |
339 | if (!completed) |
340 | goto out; | |
1da177e4 LT |
341 | } |
342 | ||
343 | ret = curmsg; | |
344 | out: | |
25985edc | 345 | DEB1("}}} transferred %d/%d messages. " |
3d438291 | 346 | "status is %#04x. control is %#04x\n", |
1da177e4 LT |
347 | curmsg, num, pca_status(adap), |
348 | pca_get_con(adap)); | |
349 | return ret; | |
350 | } | |
351 | ||
352 | static u32 pca_func(struct i2c_adapter *adap) | |
353 | { | |
2086ca48 | 354 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; |
1da177e4 LT |
355 | } |
356 | ||
c01b0831 WS |
357 | static const struct i2c_algorithm pca_algo = { |
358 | .master_xfer = pca_xfer, | |
359 | .functionality = pca_func, | |
360 | }; | |
361 | ||
eff9ec95 | 362 | static unsigned int pca_probe_chip(struct i2c_adapter *adap) |
1da177e4 | 363 | { |
c01b0831 | 364 | struct i2c_algo_pca_data *pca_data = adap->algo_data; |
eff9ec95 MAC |
365 | /* The trick here is to check if there is an indirect register |
366 | * available. If there is one, we will read the value we first | |
367 | * wrote on I2C_PCA_IADR. Otherwise, we will read the last value | |
368 | * we wrote on I2C_PCA_ADR | |
369 | */ | |
370 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); | |
371 | pca_outw(pca_data, I2C_PCA_IND, 0xAA); | |
372 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO); | |
373 | pca_outw(pca_data, I2C_PCA_IND, 0x00); | |
374 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); | |
375 | if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) { | |
376 | printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name); | |
a76e7c68 | 377 | pca_data->chip = I2C_PCA_CHIP_9665; |
eff9ec95 MAC |
378 | } else { |
379 | printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name); | |
a76e7c68 | 380 | pca_data->chip = I2C_PCA_CHIP_9564; |
c01b0831 | 381 | } |
a76e7c68 | 382 | return pca_data->chip; |
eff9ec95 MAC |
383 | } |
384 | ||
385 | static int pca_init(struct i2c_adapter *adap) | |
386 | { | |
387 | struct i2c_algo_pca_data *pca_data = adap->algo_data; | |
c01b0831 WS |
388 | |
389 | adap->algo = &pca_algo; | |
1da177e4 | 390 | |
eff9ec95 MAC |
391 | if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) { |
392 | static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36}; | |
393 | int clock; | |
394 | ||
395 | if (pca_data->i2c_clock > 7) { | |
396 | switch (pca_data->i2c_clock) { | |
397 | case 330000: | |
398 | pca_data->i2c_clock = I2C_PCA_CON_330kHz; | |
399 | break; | |
400 | case 288000: | |
401 | pca_data->i2c_clock = I2C_PCA_CON_288kHz; | |
402 | break; | |
403 | case 217000: | |
404 | pca_data->i2c_clock = I2C_PCA_CON_217kHz; | |
405 | break; | |
406 | case 146000: | |
407 | pca_data->i2c_clock = I2C_PCA_CON_146kHz; | |
408 | break; | |
409 | case 88000: | |
410 | pca_data->i2c_clock = I2C_PCA_CON_88kHz; | |
411 | break; | |
412 | case 59000: | |
413 | pca_data->i2c_clock = I2C_PCA_CON_59kHz; | |
414 | break; | |
415 | case 44000: | |
416 | pca_data->i2c_clock = I2C_PCA_CON_44kHz; | |
417 | break; | |
418 | case 36000: | |
419 | pca_data->i2c_clock = I2C_PCA_CON_36kHz; | |
420 | break; | |
421 | default: | |
422 | printk(KERN_WARNING | |
423 | "%s: Invalid I2C clock speed selected." | |
424 | " Using default 59kHz.\n", adap->name); | |
425 | pca_data->i2c_clock = I2C_PCA_CON_59kHz; | |
426 | } | |
427 | } else { | |
428 | printk(KERN_WARNING "%s: " | |
429 | "Choosing the clock frequency based on " | |
430 | "index is deprecated." | |
431 | " Use the nominal frequency.\n", adap->name); | |
432 | } | |
433 | ||
434 | pca_reset(pca_data); | |
435 | ||
436 | clock = pca_clock(pca_data); | |
437 | printk(KERN_INFO "%s: Clock frequency is %dkHz\n", | |
438 | adap->name, freqs[clock]); | |
439 | ||
440 | pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock); | |
441 | } else { | |
442 | int clock; | |
443 | int mode; | |
444 | int tlow, thi; | |
445 | /* Values can be found on PCA9665 datasheet section 7.3.2.6 */ | |
446 | int min_tlow, min_thi; | |
447 | /* These values are the maximum raise and fall values allowed | |
448 | * by the I2C operation mode (Standard, Fast or Fast+) | |
449 | * They are used (added) below to calculate the clock dividers | |
450 | * of PCA9665. Note that they are slightly different of the | |
451 | * real maximum, to allow the change on mode exactly on the | |
452 | * maximum clock rate for each mode | |
453 | */ | |
454 | int raise_fall_time; | |
455 | ||
eff9ec95 MAC |
456 | if (pca_data->i2c_clock > 1265800) { |
457 | printk(KERN_WARNING "%s: I2C clock speed too high." | |
458 | " Using 1265.8kHz.\n", adap->name); | |
459 | pca_data->i2c_clock = 1265800; | |
460 | } | |
461 | ||
462 | if (pca_data->i2c_clock < 60300) { | |
463 | printk(KERN_WARNING "%s: I2C clock speed too low." | |
464 | " Using 60.3kHz.\n", adap->name); | |
465 | pca_data->i2c_clock = 60300; | |
466 | } | |
467 | ||
468 | /* To avoid integer overflow, use clock/100 for calculations */ | |
469 | clock = pca_clock(pca_data) / 100; | |
470 | ||
5f71a3ef | 471 | if (pca_data->i2c_clock > 1000000) { |
eff9ec95 MAC |
472 | mode = I2C_PCA_MODE_TURBO; |
473 | min_tlow = 14; | |
474 | min_thi = 5; | |
475 | raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ | |
5f71a3ef | 476 | } else if (pca_data->i2c_clock > 400000) { |
eff9ec95 MAC |
477 | mode = I2C_PCA_MODE_FASTP; |
478 | min_tlow = 17; | |
479 | min_thi = 9; | |
480 | raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ | |
5f71a3ef | 481 | } else if (pca_data->i2c_clock > 100000) { |
eff9ec95 MAC |
482 | mode = I2C_PCA_MODE_FAST; |
483 | min_tlow = 44; | |
484 | min_thi = 20; | |
485 | raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */ | |
486 | } else { | |
487 | mode = I2C_PCA_MODE_STD; | |
488 | min_tlow = 157; | |
489 | min_thi = 134; | |
490 | raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */ | |
491 | } | |
492 | ||
493 | /* The minimum clock that respects the thi/tlow = 134/157 is | |
494 | * 64800 Hz. Below that, we have to fix the tlow to 255 and | |
495 | * calculate the thi factor. | |
496 | */ | |
497 | if (clock < 648) { | |
498 | tlow = 255; | |
499 | thi = 1000000 - clock * raise_fall_time; | |
500 | thi /= (I2C_PCA_OSC_PER * clock) - tlow; | |
501 | } else { | |
502 | tlow = (1000000 - clock * raise_fall_time) * min_tlow; | |
503 | tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow); | |
504 | thi = tlow * min_thi / min_tlow; | |
505 | } | |
506 | ||
507 | pca_reset(pca_data); | |
1da177e4 | 508 | |
eff9ec95 MAC |
509 | printk(KERN_INFO |
510 | "%s: Clock frequency is %dHz\n", adap->name, clock * 100); | |
1da177e4 | 511 | |
eff9ec95 MAC |
512 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE); |
513 | pca_outw(pca_data, I2C_PCA_IND, mode); | |
514 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL); | |
515 | pca_outw(pca_data, I2C_PCA_IND, tlow); | |
516 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH); | |
517 | pca_outw(pca_data, I2C_PCA_IND, thi); | |
518 | ||
519 | pca_set_con(pca_data, I2C_PCA_CON_ENSIO); | |
520 | } | |
0e6dd6a2 | 521 | udelay(500); /* 500 us for oscillator to stabilise */ |
1da177e4 LT |
522 | |
523 | return 0; | |
524 | } | |
525 | ||
3d438291 WS |
526 | /* |
527 | * registering functions to load algorithms at runtime | |
1da177e4 LT |
528 | */ |
529 | int i2c_pca_add_bus(struct i2c_adapter *adap) | |
530 | { | |
1da177e4 LT |
531 | int rval; |
532 | ||
c01b0831 WS |
533 | rval = pca_init(adap); |
534 | if (rval) | |
535 | return rval; | |
1da177e4 | 536 | |
c01b0831 WS |
537 | return i2c_add_adapter(adap); |
538 | } | |
539 | EXPORT_SYMBOL(i2c_pca_add_bus); | |
1da177e4 | 540 | |
c01b0831 WS |
541 | int i2c_pca_add_numbered_bus(struct i2c_adapter *adap) |
542 | { | |
543 | int rval; | |
1da177e4 | 544 | |
c01b0831 WS |
545 | rval = pca_init(adap); |
546 | if (rval) | |
547 | return rval; | |
1da177e4 | 548 | |
c01b0831 | 549 | return i2c_add_numbered_adapter(adap); |
1da177e4 | 550 | } |
c01b0831 | 551 | EXPORT_SYMBOL(i2c_pca_add_numbered_bus); |
1da177e4 | 552 | |
c01b0831 WS |
553 | MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, " |
554 | "Wolfram Sang <w.sang@pengutronix.de>"); | |
eff9ec95 | 555 | MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm"); |
1da177e4 LT |
556 | MODULE_LICENSE("GPL"); |
557 | ||
558 | module_param(i2c_debug, int, 0); |