Commit | Line | Data |
---|---|---|
c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 | 2 | /* |
3d438291 | 3 | * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters |
1da177e4 | 4 | * Copyright (C) 2004 Arcom Control Systems |
c01b0831 | 5 | * Copyright (C) 2008 Pengutronix |
1da177e4 LT |
6 | */ |
7 | ||
8 | #include <linux/kernel.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/moduleparam.h> | |
11 | #include <linux/delay.h> | |
8e99ada8 | 12 | #include <linux/jiffies.h> |
1da177e4 LT |
13 | #include <linux/errno.h> |
14 | #include <linux/i2c.h> | |
15 | #include <linux/i2c-algo-pca.h> | |
1da177e4 | 16 | |
bac3e7c2 FS |
17 | #define DEB1(fmt, args...) do { if (i2c_debug >= 1) \ |
18 | printk(KERN_DEBUG fmt, ## args); } while (0) | |
19 | #define DEB2(fmt, args...) do { if (i2c_debug >= 2) \ | |
20 | printk(KERN_DEBUG fmt, ## args); } while (0) | |
21 | #define DEB3(fmt, args...) do { if (i2c_debug >= 3) \ | |
22 | printk(KERN_DEBUG fmt, ## args); } while (0) | |
1da177e4 | 23 | |
60507095 | 24 | static int i2c_debug; |
1da177e4 | 25 | |
c01b0831 WS |
26 | #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val) |
27 | #define pca_inw(adap, reg) adap->read_byte(adap->data, reg) | |
1da177e4 LT |
28 | |
29 | #define pca_status(adap) pca_inw(adap, I2C_PCA_STA) | |
c01b0831 | 30 | #define pca_clock(adap) adap->i2c_clock |
1da177e4 LT |
31 | #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val) |
32 | #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON) | |
c01b0831 | 33 | #define pca_wait(adap) adap->wait_for_completion(adap->data) |
1da177e4 | 34 | |
a76e7c68 | 35 | static void pca_reset(struct i2c_algo_pca_data *adap) |
eff9ec95 | 36 | { |
a76e7c68 TK |
37 | if (adap->chip == I2C_PCA_CHIP_9665) { |
38 | /* Ignore the reset function from the module, | |
39 | * we can use the parallel bus reset. | |
40 | */ | |
41 | pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET); | |
42 | pca_outw(adap, I2C_PCA_IND, 0xA5); | |
43 | pca_outw(adap, I2C_PCA_IND, 0x5A); | |
0a355aeb EN |
44 | |
45 | /* | |
46 | * After a reset we need to re-apply any configuration | |
47 | * (calculated in pca_init) to get the bus in a working state. | |
48 | */ | |
49 | pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IMODE); | |
50 | pca_outw(adap, I2C_PCA_IND, adap->bus_settings.mode); | |
51 | pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLL); | |
52 | pca_outw(adap, I2C_PCA_IND, adap->bus_settings.tlow); | |
53 | pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLH); | |
54 | pca_outw(adap, I2C_PCA_IND, adap->bus_settings.thi); | |
55 | ||
56 | pca_set_con(adap, I2C_PCA_CON_ENSIO); | |
a76e7c68 TK |
57 | } else { |
58 | adap->reset_chip(adap->data); | |
0a355aeb | 59 | pca_set_con(adap, I2C_PCA_CON_ENSIO | adap->bus_settings.clock_freq); |
a76e7c68 | 60 | } |
eff9ec95 MAC |
61 | } |
62 | ||
1da177e4 LT |
63 | /* |
64 | * Generate a start condition on the i2c bus. | |
65 | * | |
44bbe87e | 66 | * returns after the start condition has occurred |
1da177e4 | 67 | */ |
2378bc09 | 68 | static int pca_start(struct i2c_algo_pca_data *adap) |
1da177e4 LT |
69 | { |
70 | int sta = pca_get_con(adap); | |
71 | DEB2("=== START\n"); | |
72 | sta |= I2C_PCA_CON_STA; | |
73 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); | |
74 | pca_set_con(adap, sta); | |
2378bc09 | 75 | return pca_wait(adap); |
1da177e4 LT |
76 | } |
77 | ||
78 | /* | |
46b615f4 | 79 | * Generate a repeated start condition on the i2c bus |
1da177e4 | 80 | * |
44bbe87e | 81 | * return after the repeated start condition has occurred |
1da177e4 | 82 | */ |
2378bc09 | 83 | static int pca_repeated_start(struct i2c_algo_pca_data *adap) |
1da177e4 LT |
84 | { |
85 | int sta = pca_get_con(adap); | |
86 | DEB2("=== REPEATED START\n"); | |
87 | sta |= I2C_PCA_CON_STA; | |
88 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); | |
89 | pca_set_con(adap, sta); | |
2378bc09 | 90 | return pca_wait(adap); |
1da177e4 LT |
91 | } |
92 | ||
93 | /* | |
94 | * Generate a stop condition on the i2c bus | |
95 | * | |
96 | * returns after the stop condition has been generated | |
97 | * | |
98 | * STOPs do not generate an interrupt or set the SI flag, since the | |
46b615f4 | 99 | * part returns the idle state (0xf8). Hence we don't need to |
1da177e4 LT |
100 | * pca_wait here. |
101 | */ | |
102 | static void pca_stop(struct i2c_algo_pca_data *adap) | |
103 | { | |
104 | int sta = pca_get_con(adap); | |
105 | DEB2("=== STOP\n"); | |
106 | sta |= I2C_PCA_CON_STO; | |
107 | sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI); | |
108 | pca_set_con(adap, sta); | |
109 | } | |
110 | ||
111 | /* | |
112 | * Send the slave address and R/W bit | |
113 | * | |
114 | * returns after the address has been sent | |
115 | */ | |
2378bc09 | 116 | static int pca_address(struct i2c_algo_pca_data *adap, |
2086ca48 | 117 | struct i2c_msg *msg) |
1da177e4 LT |
118 | { |
119 | int sta = pca_get_con(adap); | |
ac6d5298 | 120 | int addr = i2c_8bit_addr_from_msg(msg); |
1da177e4 | 121 | |
3d438291 | 122 | DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n", |
1da177e4 | 123 | msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr); |
3d438291 | 124 | |
1da177e4 LT |
125 | pca_outw(adap, I2C_PCA_DAT, addr); |
126 | ||
127 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); | |
128 | pca_set_con(adap, sta); | |
129 | ||
2378bc09 | 130 | return pca_wait(adap); |
1da177e4 LT |
131 | } |
132 | ||
133 | /* | |
134 | * Transmit a byte. | |
135 | * | |
136 | * Returns after the byte has been transmitted | |
137 | */ | |
2378bc09 | 138 | static int pca_tx_byte(struct i2c_algo_pca_data *adap, |
2086ca48 | 139 | __u8 b) |
1da177e4 LT |
140 | { |
141 | int sta = pca_get_con(adap); | |
142 | DEB2("=== WRITE %#04x\n", b); | |
143 | pca_outw(adap, I2C_PCA_DAT, b); | |
144 | ||
145 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); | |
146 | pca_set_con(adap, sta); | |
147 | ||
2378bc09 | 148 | return pca_wait(adap); |
1da177e4 LT |
149 | } |
150 | ||
151 | /* | |
152 | * Receive a byte | |
153 | * | |
154 | * returns immediately. | |
155 | */ | |
3d438291 | 156 | static void pca_rx_byte(struct i2c_algo_pca_data *adap, |
1da177e4 LT |
157 | __u8 *b, int ack) |
158 | { | |
159 | *b = pca_inw(adap, I2C_PCA_DAT); | |
160 | DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK"); | |
161 | } | |
162 | ||
3d438291 | 163 | /* |
1da177e4 LT |
164 | * Setup ACK or NACK for next received byte and wait for it to arrive. |
165 | * | |
166 | * Returns after next byte has arrived. | |
167 | */ | |
2378bc09 | 168 | static int pca_rx_ack(struct i2c_algo_pca_data *adap, |
2086ca48 | 169 | int ack) |
1da177e4 LT |
170 | { |
171 | int sta = pca_get_con(adap); | |
172 | ||
173 | sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA); | |
174 | ||
2086ca48 | 175 | if (ack) |
1da177e4 LT |
176 | sta |= I2C_PCA_CON_AA; |
177 | ||
178 | pca_set_con(adap, sta); | |
2378bc09 | 179 | return pca_wait(adap); |
1da177e4 LT |
180 | } |
181 | ||
1da177e4 | 182 | static int pca_xfer(struct i2c_adapter *i2c_adap, |
2086ca48 FH |
183 | struct i2c_msg *msgs, |
184 | int num) | |
1da177e4 | 185 | { |
2086ca48 FH |
186 | struct i2c_algo_pca_data *adap = i2c_adap->algo_data; |
187 | struct i2c_msg *msg = NULL; | |
188 | int curmsg; | |
1da177e4 LT |
189 | int numbytes = 0; |
190 | int state; | |
191 | int ret; | |
2378bc09 | 192 | int completed = 1; |
8e99ada8 WS |
193 | unsigned long timeout = jiffies + i2c_adap->timeout; |
194 | ||
c454dee2 | 195 | while ((state = pca_status(adap)) != 0xf8) { |
8e99ada8 WS |
196 | if (time_before(jiffies, timeout)) { |
197 | msleep(10); | |
198 | } else { | |
199 | dev_dbg(&i2c_adap->dev, "bus is not idle. status is " | |
200 | "%#04x\n", state); | |
4403988a | 201 | return -EBUSY; |
8e99ada8 | 202 | } |
1da177e4 LT |
203 | } |
204 | ||
205 | DEB1("{{{ XFER %d messages\n", num); | |
206 | ||
2086ca48 | 207 | if (i2c_debug >= 2) { |
1da177e4 LT |
208 | for (curmsg = 0; curmsg < num; curmsg++) { |
209 | int addr, i; | |
210 | msg = &msgs[curmsg]; | |
3d438291 | 211 | |
1da177e4 | 212 | addr = (0x7f & msg->addr) ; |
3d438291 | 213 | |
2086ca48 | 214 | if (msg->flags & I2C_M_RD) |
3d438291 | 215 | printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n", |
2086ca48 | 216 | curmsg, msg->len, addr, (addr << 1) | 1); |
1da177e4 | 217 | else { |
3d438291 | 218 | printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s", |
2086ca48 | 219 | curmsg, msg->len, addr, addr << 1, |
1da177e4 | 220 | msg->len == 0 ? "" : ", "); |
2086ca48 | 221 | for (i = 0; i < msg->len; i++) |
1da177e4 LT |
222 | printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", "); |
223 | printk("]\n"); | |
224 | } | |
225 | } | |
226 | } | |
227 | ||
228 | curmsg = 0; | |
4403988a | 229 | ret = -EIO; |
1da177e4 LT |
230 | while (curmsg < num) { |
231 | state = pca_status(adap); | |
232 | ||
233 | DEB3("STATE is 0x%02x\n", state); | |
234 | msg = &msgs[curmsg]; | |
235 | ||
236 | switch (state) { | |
237 | case 0xf8: /* On reset or stop the bus is idle */ | |
2378bc09 | 238 | completed = pca_start(adap); |
1da177e4 LT |
239 | break; |
240 | ||
241 | case 0x08: /* A START condition has been transmitted */ | |
242 | case 0x10: /* A repeated start condition has been transmitted */ | |
2378bc09 | 243 | completed = pca_address(adap, msg); |
1da177e4 | 244 | break; |
3d438291 | 245 | |
1da177e4 LT |
246 | case 0x18: /* SLA+W has been transmitted; ACK has been received */ |
247 | case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */ | |
248 | if (numbytes < msg->len) { | |
2378bc09 WS |
249 | completed = pca_tx_byte(adap, |
250 | msg->buf[numbytes]); | |
1da177e4 LT |
251 | numbytes++; |
252 | break; | |
253 | } | |
254 | curmsg++; numbytes = 0; | |
255 | if (curmsg == num) | |
256 | pca_stop(adap); | |
257 | else | |
2378bc09 | 258 | completed = pca_repeated_start(adap); |
1da177e4 LT |
259 | break; |
260 | ||
261 | case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */ | |
262 | DEB2("NOT ACK received after SLA+W\n"); | |
263 | pca_stop(adap); | |
4403988a | 264 | ret = -ENXIO; |
1da177e4 LT |
265 | goto out; |
266 | ||
267 | case 0x40: /* SLA+R has been transmitted; ACK has been received */ | |
2378bc09 | 268 | completed = pca_rx_ack(adap, msg->len > 1); |
1da177e4 LT |
269 | break; |
270 | ||
271 | case 0x50: /* Data bytes has been received; ACK has been returned */ | |
272 | if (numbytes < msg->len) { | |
273 | pca_rx_byte(adap, &msg->buf[numbytes], 1); | |
274 | numbytes++; | |
2378bc09 WS |
275 | completed = pca_rx_ack(adap, |
276 | numbytes < msg->len - 1); | |
1da177e4 LT |
277 | break; |
278 | } | |
279 | curmsg++; numbytes = 0; | |
280 | if (curmsg == num) | |
281 | pca_stop(adap); | |
282 | else | |
2378bc09 | 283 | completed = pca_repeated_start(adap); |
1da177e4 LT |
284 | break; |
285 | ||
286 | case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */ | |
287 | DEB2("NOT ACK received after SLA+R\n"); | |
288 | pca_stop(adap); | |
4403988a | 289 | ret = -ENXIO; |
1da177e4 LT |
290 | goto out; |
291 | ||
292 | case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ | |
293 | DEB2("NOT ACK received after data byte\n"); | |
2196d1cf | 294 | pca_stop(adap); |
1da177e4 LT |
295 | goto out; |
296 | ||
297 | case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ | |
298 | DEB2("Arbitration lost\n"); | |
2196d1cf EB |
299 | /* |
300 | * The PCA9564 data sheet (2006-09-01) says "A | |
301 | * START condition will be transmitted when the | |
302 | * bus becomes free (STOP or SCL and SDA high)" | |
303 | * when the STA bit is set (p. 11). | |
304 | * | |
305 | * In case this won't work, try pca_reset() | |
306 | * instead. | |
307 | */ | |
308 | pca_start(adap); | |
1da177e4 | 309 | goto out; |
3d438291 | 310 | |
1da177e4 | 311 | case 0x58: /* Data byte has been received; NOT ACK has been returned */ |
2086ca48 | 312 | if (numbytes == msg->len - 1) { |
1da177e4 LT |
313 | pca_rx_byte(adap, &msg->buf[numbytes], 0); |
314 | curmsg++; numbytes = 0; | |
315 | if (curmsg == num) | |
316 | pca_stop(adap); | |
317 | else | |
2378bc09 | 318 | completed = pca_repeated_start(adap); |
1da177e4 LT |
319 | } else { |
320 | DEB2("NOT ACK sent after data byte received. " | |
321 | "Not final byte. numbytes %d. len %d\n", | |
322 | numbytes, msg->len); | |
323 | pca_stop(adap); | |
324 | goto out; | |
325 | } | |
326 | break; | |
327 | case 0x70: /* Bus error - SDA stuck low */ | |
328 | DEB2("BUS ERROR - SDA Stuck low\n"); | |
329 | pca_reset(adap); | |
330 | goto out; | |
cd217f23 CP |
331 | case 0x78: /* Bus error - SCL stuck low (PCA9665) */ |
332 | case 0x90: /* Bus error - SCL stuck low (PCA9564) */ | |
1da177e4 LT |
333 | DEB2("BUS ERROR - SCL Stuck low\n"); |
334 | pca_reset(adap); | |
335 | goto out; | |
336 | case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */ | |
337 | DEB2("BUS ERROR - Illegal START or STOP\n"); | |
338 | pca_reset(adap); | |
339 | goto out; | |
340 | default: | |
c01b0831 | 341 | dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state); |
1da177e4 LT |
342 | break; |
343 | } | |
3d438291 | 344 | |
2378bc09 WS |
345 | if (!completed) |
346 | goto out; | |
1da177e4 LT |
347 | } |
348 | ||
349 | ret = curmsg; | |
350 | out: | |
25985edc | 351 | DEB1("}}} transferred %d/%d messages. " |
3d438291 | 352 | "status is %#04x. control is %#04x\n", |
1da177e4 LT |
353 | curmsg, num, pca_status(adap), |
354 | pca_get_con(adap)); | |
355 | return ret; | |
356 | } | |
357 | ||
358 | static u32 pca_func(struct i2c_adapter *adap) | |
359 | { | |
2086ca48 | 360 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; |
1da177e4 LT |
361 | } |
362 | ||
c01b0831 WS |
363 | static const struct i2c_algorithm pca_algo = { |
364 | .master_xfer = pca_xfer, | |
365 | .functionality = pca_func, | |
366 | }; | |
367 | ||
eff9ec95 | 368 | static unsigned int pca_probe_chip(struct i2c_adapter *adap) |
1da177e4 | 369 | { |
c01b0831 | 370 | struct i2c_algo_pca_data *pca_data = adap->algo_data; |
eff9ec95 MAC |
371 | /* The trick here is to check if there is an indirect register |
372 | * available. If there is one, we will read the value we first | |
373 | * wrote on I2C_PCA_IADR. Otherwise, we will read the last value | |
374 | * we wrote on I2C_PCA_ADR | |
375 | */ | |
376 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); | |
377 | pca_outw(pca_data, I2C_PCA_IND, 0xAA); | |
378 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO); | |
379 | pca_outw(pca_data, I2C_PCA_IND, 0x00); | |
380 | pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); | |
381 | if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) { | |
382 | printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name); | |
a76e7c68 | 383 | pca_data->chip = I2C_PCA_CHIP_9665; |
eff9ec95 MAC |
384 | } else { |
385 | printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name); | |
a76e7c68 | 386 | pca_data->chip = I2C_PCA_CHIP_9564; |
c01b0831 | 387 | } |
a76e7c68 | 388 | return pca_data->chip; |
eff9ec95 MAC |
389 | } |
390 | ||
391 | static int pca_init(struct i2c_adapter *adap) | |
392 | { | |
393 | struct i2c_algo_pca_data *pca_data = adap->algo_data; | |
c01b0831 WS |
394 | |
395 | adap->algo = &pca_algo; | |
1da177e4 | 396 | |
eff9ec95 MAC |
397 | if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) { |
398 | static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36}; | |
399 | int clock; | |
400 | ||
401 | if (pca_data->i2c_clock > 7) { | |
402 | switch (pca_data->i2c_clock) { | |
403 | case 330000: | |
404 | pca_data->i2c_clock = I2C_PCA_CON_330kHz; | |
405 | break; | |
406 | case 288000: | |
407 | pca_data->i2c_clock = I2C_PCA_CON_288kHz; | |
408 | break; | |
409 | case 217000: | |
410 | pca_data->i2c_clock = I2C_PCA_CON_217kHz; | |
411 | break; | |
412 | case 146000: | |
413 | pca_data->i2c_clock = I2C_PCA_CON_146kHz; | |
414 | break; | |
415 | case 88000: | |
416 | pca_data->i2c_clock = I2C_PCA_CON_88kHz; | |
417 | break; | |
418 | case 59000: | |
419 | pca_data->i2c_clock = I2C_PCA_CON_59kHz; | |
420 | break; | |
421 | case 44000: | |
422 | pca_data->i2c_clock = I2C_PCA_CON_44kHz; | |
423 | break; | |
424 | case 36000: | |
425 | pca_data->i2c_clock = I2C_PCA_CON_36kHz; | |
426 | break; | |
427 | default: | |
428 | printk(KERN_WARNING | |
429 | "%s: Invalid I2C clock speed selected." | |
430 | " Using default 59kHz.\n", adap->name); | |
431 | pca_data->i2c_clock = I2C_PCA_CON_59kHz; | |
432 | } | |
433 | } else { | |
434 | printk(KERN_WARNING "%s: " | |
435 | "Choosing the clock frequency based on " | |
436 | "index is deprecated." | |
437 | " Use the nominal frequency.\n", adap->name); | |
438 | } | |
439 | ||
eff9ec95 MAC |
440 | clock = pca_clock(pca_data); |
441 | printk(KERN_INFO "%s: Clock frequency is %dkHz\n", | |
442 | adap->name, freqs[clock]); | |
443 | ||
0a355aeb EN |
444 | /* Store settings as these will be needed when the PCA chip is reset */ |
445 | pca_data->bus_settings.clock_freq = clock; | |
446 | ||
447 | pca_reset(pca_data); | |
eff9ec95 MAC |
448 | } else { |
449 | int clock; | |
450 | int mode; | |
451 | int tlow, thi; | |
452 | /* Values can be found on PCA9665 datasheet section 7.3.2.6 */ | |
453 | int min_tlow, min_thi; | |
454 | /* These values are the maximum raise and fall values allowed | |
455 | * by the I2C operation mode (Standard, Fast or Fast+) | |
456 | * They are used (added) below to calculate the clock dividers | |
457 | * of PCA9665. Note that they are slightly different of the | |
458 | * real maximum, to allow the change on mode exactly on the | |
459 | * maximum clock rate for each mode | |
460 | */ | |
461 | int raise_fall_time; | |
462 | ||
eff9ec95 MAC |
463 | if (pca_data->i2c_clock > 1265800) { |
464 | printk(KERN_WARNING "%s: I2C clock speed too high." | |
465 | " Using 1265.8kHz.\n", adap->name); | |
466 | pca_data->i2c_clock = 1265800; | |
467 | } | |
468 | ||
469 | if (pca_data->i2c_clock < 60300) { | |
470 | printk(KERN_WARNING "%s: I2C clock speed too low." | |
471 | " Using 60.3kHz.\n", adap->name); | |
472 | pca_data->i2c_clock = 60300; | |
473 | } | |
474 | ||
475 | /* To avoid integer overflow, use clock/100 for calculations */ | |
476 | clock = pca_clock(pca_data) / 100; | |
477 | ||
7b8c4c0b | 478 | if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_PLUS_FREQ) { |
eff9ec95 MAC |
479 | mode = I2C_PCA_MODE_TURBO; |
480 | min_tlow = 14; | |
481 | min_thi = 5; | |
482 | raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ | |
7b8c4c0b | 483 | } else if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_FREQ) { |
eff9ec95 MAC |
484 | mode = I2C_PCA_MODE_FASTP; |
485 | min_tlow = 17; | |
486 | min_thi = 9; | |
487 | raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ | |
7b8c4c0b | 488 | } else if (pca_data->i2c_clock > I2C_MAX_STANDARD_MODE_FREQ) { |
eff9ec95 MAC |
489 | mode = I2C_PCA_MODE_FAST; |
490 | min_tlow = 44; | |
491 | min_thi = 20; | |
492 | raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */ | |
493 | } else { | |
494 | mode = I2C_PCA_MODE_STD; | |
495 | min_tlow = 157; | |
496 | min_thi = 134; | |
497 | raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */ | |
498 | } | |
499 | ||
500 | /* The minimum clock that respects the thi/tlow = 134/157 is | |
501 | * 64800 Hz. Below that, we have to fix the tlow to 255 and | |
502 | * calculate the thi factor. | |
503 | */ | |
504 | if (clock < 648) { | |
505 | tlow = 255; | |
506 | thi = 1000000 - clock * raise_fall_time; | |
507 | thi /= (I2C_PCA_OSC_PER * clock) - tlow; | |
508 | } else { | |
509 | tlow = (1000000 - clock * raise_fall_time) * min_tlow; | |
510 | tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow); | |
511 | thi = tlow * min_thi / min_tlow; | |
512 | } | |
513 | ||
0a355aeb EN |
514 | /* Store settings as these will be needed when the PCA chip is reset */ |
515 | pca_data->bus_settings.mode = mode; | |
516 | pca_data->bus_settings.tlow = tlow; | |
517 | pca_data->bus_settings.thi = thi; | |
518 | ||
eff9ec95 | 519 | pca_reset(pca_data); |
1da177e4 | 520 | |
eff9ec95 MAC |
521 | printk(KERN_INFO |
522 | "%s: Clock frequency is %dHz\n", adap->name, clock * 100); | |
eff9ec95 | 523 | } |
0e6dd6a2 | 524 | udelay(500); /* 500 us for oscillator to stabilise */ |
1da177e4 LT |
525 | |
526 | return 0; | |
527 | } | |
528 | ||
3d438291 WS |
529 | /* |
530 | * registering functions to load algorithms at runtime | |
1da177e4 LT |
531 | */ |
532 | int i2c_pca_add_bus(struct i2c_adapter *adap) | |
533 | { | |
1da177e4 LT |
534 | int rval; |
535 | ||
c01b0831 WS |
536 | rval = pca_init(adap); |
537 | if (rval) | |
538 | return rval; | |
1da177e4 | 539 | |
c01b0831 WS |
540 | return i2c_add_adapter(adap); |
541 | } | |
542 | EXPORT_SYMBOL(i2c_pca_add_bus); | |
1da177e4 | 543 | |
c01b0831 WS |
544 | int i2c_pca_add_numbered_bus(struct i2c_adapter *adap) |
545 | { | |
546 | int rval; | |
1da177e4 | 547 | |
c01b0831 WS |
548 | rval = pca_init(adap); |
549 | if (rval) | |
550 | return rval; | |
1da177e4 | 551 | |
c01b0831 | 552 | return i2c_add_numbered_adapter(adap); |
1da177e4 | 553 | } |
c01b0831 | 554 | EXPORT_SYMBOL(i2c_pca_add_numbered_bus); |
1da177e4 | 555 | |
f80531c8 JN |
556 | MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>"); |
557 | MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>"); | |
eff9ec95 | 558 | MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm"); |
1da177e4 LT |
559 | MODULE_LICENSE("GPL"); |
560 | ||
561 | module_param(i2c_debug, int, 0); |