2 * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
3 * Copyright (C) 2004 Arcom Control Systems
4 * Copyright (C) 2008 Pengutronix
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.
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.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/delay.h>
26 #include <linux/jiffies.h>
27 #include <linux/init.h>
28 #include <linux/errno.h>
29 #include <linux/i2c.h>
30 #include <linux/i2c-algo-pca.h>
32 #define DEB1(fmt, args...) do { if (i2c_debug >= 1) \
33 printk(KERN_DEBUG fmt, ## args); } while (0)
34 #define DEB2(fmt, args...) do { if (i2c_debug >= 2) \
35 printk(KERN_DEBUG fmt, ## args); } while (0)
36 #define DEB3(fmt, args...) do { if (i2c_debug >= 3) \
37 printk(KERN_DEBUG fmt, ## args); } while (0)
41 #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
42 #define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
44 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
45 #define pca_clock(adap) adap->i2c_clock
46 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
47 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
48 #define pca_wait(adap) adap->wait_for_completion(adap->data)
50 static void pca_reset(struct i2c_algo_pca_data
*adap
)
52 if (adap
->chip
== I2C_PCA_CHIP_9665
) {
53 /* Ignore the reset function from the module,
54 * we can use the parallel bus reset.
56 pca_outw(adap
, I2C_PCA_INDPTR
, I2C_PCA_IPRESET
);
57 pca_outw(adap
, I2C_PCA_IND
, 0xA5);
58 pca_outw(adap
, I2C_PCA_IND
, 0x5A);
60 adap
->reset_chip(adap
->data
);
65 * Generate a start condition on the i2c bus.
67 * returns after the start condition has occurred
69 static int pca_start(struct i2c_algo_pca_data
*adap
)
71 int sta
= pca_get_con(adap
);
73 sta
|= I2C_PCA_CON_STA
;
74 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_SI
);
75 pca_set_con(adap
, sta
);
76 return pca_wait(adap
);
80 * Generate a repeated start condition on the i2c bus
82 * return after the repeated start condition has occurred
84 static int pca_repeated_start(struct i2c_algo_pca_data
*adap
)
86 int sta
= pca_get_con(adap
);
87 DEB2("=== REPEATED START\n");
88 sta
|= I2C_PCA_CON_STA
;
89 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_SI
);
90 pca_set_con(adap
, sta
);
91 return pca_wait(adap
);
95 * Generate a stop condition on the i2c bus
97 * returns after the stop condition has been generated
99 * STOPs do not generate an interrupt or set the SI flag, since the
100 * part returns the idle state (0xf8). Hence we don't need to
103 static void pca_stop(struct i2c_algo_pca_data
*adap
)
105 int sta
= pca_get_con(adap
);
107 sta
|= I2C_PCA_CON_STO
;
108 sta
&= ~(I2C_PCA_CON_STA
|I2C_PCA_CON_SI
);
109 pca_set_con(adap
, sta
);
113 * Send the slave address and R/W bit
115 * returns after the address has been sent
117 static int pca_address(struct i2c_algo_pca_data
*adap
,
120 int sta
= pca_get_con(adap
);
123 addr
= ((0x7f & msg
->addr
) << 1);
124 if (msg
->flags
& I2C_M_RD
)
126 DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
127 msg
->addr
, msg
->flags
& I2C_M_RD
? 'R' : 'W', addr
);
129 pca_outw(adap
, I2C_PCA_DAT
, addr
);
131 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_STA
|I2C_PCA_CON_SI
);
132 pca_set_con(adap
, sta
);
134 return pca_wait(adap
);
140 * Returns after the byte has been transmitted
142 static int pca_tx_byte(struct i2c_algo_pca_data
*adap
,
145 int sta
= pca_get_con(adap
);
146 DEB2("=== WRITE %#04x\n", b
);
147 pca_outw(adap
, I2C_PCA_DAT
, b
);
149 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_STA
|I2C_PCA_CON_SI
);
150 pca_set_con(adap
, sta
);
152 return pca_wait(adap
);
158 * returns immediately.
160 static void pca_rx_byte(struct i2c_algo_pca_data
*adap
,
163 *b
= pca_inw(adap
, I2C_PCA_DAT
);
164 DEB2("=== READ %#04x %s\n", *b
, ack
? "ACK" : "NACK");
168 * Setup ACK or NACK for next received byte and wait for it to arrive.
170 * Returns after next byte has arrived.
172 static int pca_rx_ack(struct i2c_algo_pca_data
*adap
,
175 int sta
= pca_get_con(adap
);
177 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_STA
|I2C_PCA_CON_SI
|I2C_PCA_CON_AA
);
180 sta
|= I2C_PCA_CON_AA
;
182 pca_set_con(adap
, sta
);
183 return pca_wait(adap
);
186 static int pca_xfer(struct i2c_adapter
*i2c_adap
,
187 struct i2c_msg
*msgs
,
190 struct i2c_algo_pca_data
*adap
= i2c_adap
->algo_data
;
191 struct i2c_msg
*msg
= NULL
;
197 unsigned long timeout
= jiffies
+ i2c_adap
->timeout
;
199 while ((state
= pca_status(adap
)) != 0xf8) {
200 if (time_before(jiffies
, timeout
)) {
203 dev_dbg(&i2c_adap
->dev
, "bus is not idle. status is "
209 DEB1("{{{ XFER %d messages\n", num
);
211 if (i2c_debug
>= 2) {
212 for (curmsg
= 0; curmsg
< num
; curmsg
++) {
216 addr
= (0x7f & msg
->addr
) ;
218 if (msg
->flags
& I2C_M_RD
)
219 printk(KERN_INFO
" [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
220 curmsg
, msg
->len
, addr
, (addr
<< 1) | 1);
222 printk(KERN_INFO
" [%02d] WR %d bytes to %#02x [%#02x%s",
223 curmsg
, msg
->len
, addr
, addr
<< 1,
224 msg
->len
== 0 ? "" : ", ");
225 for (i
= 0; i
< msg
->len
; i
++)
226 printk("%#04x%s", msg
->buf
[i
], i
== msg
->len
- 1 ? "" : ", ");
234 while (curmsg
< num
) {
235 state
= pca_status(adap
);
237 DEB3("STATE is 0x%02x\n", state
);
241 case 0xf8: /* On reset or stop the bus is idle */
242 completed
= pca_start(adap
);
245 case 0x08: /* A START condition has been transmitted */
246 case 0x10: /* A repeated start condition has been transmitted */
247 completed
= pca_address(adap
, msg
);
250 case 0x18: /* SLA+W has been transmitted; ACK has been received */
251 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
252 if (numbytes
< msg
->len
) {
253 completed
= pca_tx_byte(adap
,
258 curmsg
++; numbytes
= 0;
262 completed
= pca_repeated_start(adap
);
265 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
266 DEB2("NOT ACK received after SLA+W\n");
271 case 0x40: /* SLA+R has been transmitted; ACK has been received */
272 completed
= pca_rx_ack(adap
, msg
->len
> 1);
275 case 0x50: /* Data bytes has been received; ACK has been returned */
276 if (numbytes
< msg
->len
) {
277 pca_rx_byte(adap
, &msg
->buf
[numbytes
], 1);
279 completed
= pca_rx_ack(adap
,
280 numbytes
< msg
->len
- 1);
283 curmsg
++; numbytes
= 0;
287 completed
= pca_repeated_start(adap
);
290 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
291 DEB2("NOT ACK received after SLA+R\n");
296 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
297 DEB2("NOT ACK received after data byte\n");
301 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
302 DEB2("Arbitration lost\n");
304 * The PCA9564 data sheet (2006-09-01) says "A
305 * START condition will be transmitted when the
306 * bus becomes free (STOP or SCL and SDA high)"
307 * when the STA bit is set (p. 11).
309 * In case this won't work, try pca_reset()
315 case 0x58: /* Data byte has been received; NOT ACK has been returned */
316 if (numbytes
== msg
->len
- 1) {
317 pca_rx_byte(adap
, &msg
->buf
[numbytes
], 0);
318 curmsg
++; numbytes
= 0;
322 completed
= pca_repeated_start(adap
);
324 DEB2("NOT ACK sent after data byte received. "
325 "Not final byte. numbytes %d. len %d\n",
331 case 0x70: /* Bus error - SDA stuck low */
332 DEB2("BUS ERROR - SDA Stuck low\n");
335 case 0x90: /* Bus error - SCL stuck low */
336 DEB2("BUS ERROR - SCL Stuck low\n");
339 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
340 DEB2("BUS ERROR - Illegal START or STOP\n");
344 dev_err(&i2c_adap
->dev
, "unhandled SIO state 0x%02x\n", state
);
354 DEB1("}}} transferred %d/%d messages. "
355 "status is %#04x. control is %#04x\n",
356 curmsg
, num
, pca_status(adap
),
361 static u32
pca_func(struct i2c_adapter
*adap
)
363 return I2C_FUNC_I2C
| I2C_FUNC_SMBUS_EMUL
;
366 static const struct i2c_algorithm pca_algo
= {
367 .master_xfer
= pca_xfer
,
368 .functionality
= pca_func
,
371 static unsigned int pca_probe_chip(struct i2c_adapter
*adap
)
373 struct i2c_algo_pca_data
*pca_data
= adap
->algo_data
;
374 /* The trick here is to check if there is an indirect register
375 * available. If there is one, we will read the value we first
376 * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
377 * we wrote on I2C_PCA_ADR
379 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_IADR
);
380 pca_outw(pca_data
, I2C_PCA_IND
, 0xAA);
381 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_ITO
);
382 pca_outw(pca_data
, I2C_PCA_IND
, 0x00);
383 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_IADR
);
384 if (pca_inw(pca_data
, I2C_PCA_IND
) == 0xAA) {
385 printk(KERN_INFO
"%s: PCA9665 detected.\n", adap
->name
);
386 pca_data
->chip
= I2C_PCA_CHIP_9665
;
388 printk(KERN_INFO
"%s: PCA9564 detected.\n", adap
->name
);
389 pca_data
->chip
= I2C_PCA_CHIP_9564
;
391 return pca_data
->chip
;
394 static int pca_init(struct i2c_adapter
*adap
)
396 struct i2c_algo_pca_data
*pca_data
= adap
->algo_data
;
398 adap
->algo
= &pca_algo
;
400 if (pca_probe_chip(adap
) == I2C_PCA_CHIP_9564
) {
401 static int freqs
[] = {330, 288, 217, 146, 88, 59, 44, 36};
404 if (pca_data
->i2c_clock
> 7) {
405 switch (pca_data
->i2c_clock
) {
407 pca_data
->i2c_clock
= I2C_PCA_CON_330kHz
;
410 pca_data
->i2c_clock
= I2C_PCA_CON_288kHz
;
413 pca_data
->i2c_clock
= I2C_PCA_CON_217kHz
;
416 pca_data
->i2c_clock
= I2C_PCA_CON_146kHz
;
419 pca_data
->i2c_clock
= I2C_PCA_CON_88kHz
;
422 pca_data
->i2c_clock
= I2C_PCA_CON_59kHz
;
425 pca_data
->i2c_clock
= I2C_PCA_CON_44kHz
;
428 pca_data
->i2c_clock
= I2C_PCA_CON_36kHz
;
432 "%s: Invalid I2C clock speed selected."
433 " Using default 59kHz.\n", adap
->name
);
434 pca_data
->i2c_clock
= I2C_PCA_CON_59kHz
;
437 printk(KERN_WARNING
"%s: "
438 "Choosing the clock frequency based on "
439 "index is deprecated."
440 " Use the nominal frequency.\n", adap
->name
);
445 clock
= pca_clock(pca_data
);
446 printk(KERN_INFO
"%s: Clock frequency is %dkHz\n",
447 adap
->name
, freqs
[clock
]);
449 pca_set_con(pca_data
, I2C_PCA_CON_ENSIO
| clock
);
454 /* Values can be found on PCA9665 datasheet section 7.3.2.6 */
455 int min_tlow
, min_thi
;
456 /* These values are the maximum raise and fall values allowed
457 * by the I2C operation mode (Standard, Fast or Fast+)
458 * They are used (added) below to calculate the clock dividers
459 * of PCA9665. Note that they are slightly different of the
460 * real maximum, to allow the change on mode exactly on the
461 * maximum clock rate for each mode
465 if (pca_data
->i2c_clock
> 1265800) {
466 printk(KERN_WARNING
"%s: I2C clock speed too high."
467 " Using 1265.8kHz.\n", adap
->name
);
468 pca_data
->i2c_clock
= 1265800;
471 if (pca_data
->i2c_clock
< 60300) {
472 printk(KERN_WARNING
"%s: I2C clock speed too low."
473 " Using 60.3kHz.\n", adap
->name
);
474 pca_data
->i2c_clock
= 60300;
477 /* To avoid integer overflow, use clock/100 for calculations */
478 clock
= pca_clock(pca_data
) / 100;
480 if (pca_data
->i2c_clock
> 1000000) {
481 mode
= I2C_PCA_MODE_TURBO
;
484 raise_fall_time
= 22; /* Raise 11e-8s, Fall 11e-8s */
485 } else if (pca_data
->i2c_clock
> 400000) {
486 mode
= I2C_PCA_MODE_FASTP
;
489 raise_fall_time
= 22; /* Raise 11e-8s, Fall 11e-8s */
490 } else if (pca_data
->i2c_clock
> 100000) {
491 mode
= I2C_PCA_MODE_FAST
;
494 raise_fall_time
= 58; /* Raise 29e-8s, Fall 29e-8s */
496 mode
= I2C_PCA_MODE_STD
;
499 raise_fall_time
= 127; /* Raise 29e-8s, Fall 98e-8s */
502 /* The minimum clock that respects the thi/tlow = 134/157 is
503 * 64800 Hz. Below that, we have to fix the tlow to 255 and
504 * calculate the thi factor.
508 thi
= 1000000 - clock
* raise_fall_time
;
509 thi
/= (I2C_PCA_OSC_PER
* clock
) - tlow
;
511 tlow
= (1000000 - clock
* raise_fall_time
) * min_tlow
;
512 tlow
/= I2C_PCA_OSC_PER
* clock
* (min_thi
+ min_tlow
);
513 thi
= tlow
* min_thi
/ min_tlow
;
519 "%s: Clock frequency is %dHz\n", adap
->name
, clock
* 100);
521 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_IMODE
);
522 pca_outw(pca_data
, I2C_PCA_IND
, mode
);
523 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_ISCLL
);
524 pca_outw(pca_data
, I2C_PCA_IND
, tlow
);
525 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_ISCLH
);
526 pca_outw(pca_data
, I2C_PCA_IND
, thi
);
528 pca_set_con(pca_data
, I2C_PCA_CON_ENSIO
);
530 udelay(500); /* 500 us for oscilator to stabilise */
536 * registering functions to load algorithms at runtime
538 int i2c_pca_add_bus(struct i2c_adapter
*adap
)
542 rval
= pca_init(adap
);
546 return i2c_add_adapter(adap
);
548 EXPORT_SYMBOL(i2c_pca_add_bus
);
550 int i2c_pca_add_numbered_bus(struct i2c_adapter
*adap
)
554 rval
= pca_init(adap
);
558 return i2c_add_numbered_adapter(adap
);
560 EXPORT_SYMBOL(i2c_pca_add_numbered_bus
);
562 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
563 "Wolfram Sang <w.sang@pengutronix.de>");
564 MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
565 MODULE_LICENSE("GPL");
567 module_param(i2c_debug
, int, 0);