1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
4 * Copyright (C) 2004 Arcom Control Systems
5 * Copyright (C) 2008 Pengutronix
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/delay.h>
12 #include <linux/jiffies.h>
13 #include <linux/errno.h>
14 #include <linux/i2c.h>
15 #include <linux/i2c-algo-pca.h>
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)
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)
29 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
30 #define pca_clock(adap) adap->i2c_clock
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)
33 #define pca_wait(adap) adap->wait_for_completion(adap->data)
35 static void pca_reset(struct i2c_algo_pca_data
*adap
)
37 if (adap
->chip
== I2C_PCA_CHIP_9665
) {
38 /* Ignore the reset function from the module,
39 * we can use the parallel bus reset.
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);
45 adap
->reset_chip(adap
->data
);
50 * Generate a start condition on the i2c bus.
52 * returns after the start condition has occurred
54 static int pca_start(struct i2c_algo_pca_data
*adap
)
56 int sta
= pca_get_con(adap
);
58 sta
|= I2C_PCA_CON_STA
;
59 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_SI
);
60 pca_set_con(adap
, sta
);
61 return pca_wait(adap
);
65 * Generate a repeated start condition on the i2c bus
67 * return after the repeated start condition has occurred
69 static int pca_repeated_start(struct i2c_algo_pca_data
*adap
)
71 int sta
= pca_get_con(adap
);
72 DEB2("=== REPEATED START\n");
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 stop condition on the i2c bus
82 * returns after the stop condition has been generated
84 * STOPs do not generate an interrupt or set the SI flag, since the
85 * part returns the idle state (0xf8). Hence we don't need to
88 static void pca_stop(struct i2c_algo_pca_data
*adap
)
90 int sta
= pca_get_con(adap
);
92 sta
|= I2C_PCA_CON_STO
;
93 sta
&= ~(I2C_PCA_CON_STA
|I2C_PCA_CON_SI
);
94 pca_set_con(adap
, sta
);
98 * Send the slave address and R/W bit
100 * returns after the address has been sent
102 static int pca_address(struct i2c_algo_pca_data
*adap
,
105 int sta
= pca_get_con(adap
);
106 int addr
= i2c_8bit_addr_from_msg(msg
);
108 DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
109 msg
->addr
, msg
->flags
& I2C_M_RD
? 'R' : 'W', addr
);
111 pca_outw(adap
, I2C_PCA_DAT
, addr
);
113 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_STA
|I2C_PCA_CON_SI
);
114 pca_set_con(adap
, sta
);
116 return pca_wait(adap
);
122 * Returns after the byte has been transmitted
124 static int pca_tx_byte(struct i2c_algo_pca_data
*adap
,
127 int sta
= pca_get_con(adap
);
128 DEB2("=== WRITE %#04x\n", b
);
129 pca_outw(adap
, I2C_PCA_DAT
, b
);
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 immediately.
142 static void pca_rx_byte(struct i2c_algo_pca_data
*adap
,
145 *b
= pca_inw(adap
, I2C_PCA_DAT
);
146 DEB2("=== READ %#04x %s\n", *b
, ack
? "ACK" : "NACK");
150 * Setup ACK or NACK for next received byte and wait for it to arrive.
152 * Returns after next byte has arrived.
154 static int pca_rx_ack(struct i2c_algo_pca_data
*adap
,
157 int sta
= pca_get_con(adap
);
159 sta
&= ~(I2C_PCA_CON_STO
|I2C_PCA_CON_STA
|I2C_PCA_CON_SI
|I2C_PCA_CON_AA
);
162 sta
|= I2C_PCA_CON_AA
;
164 pca_set_con(adap
, sta
);
165 return pca_wait(adap
);
168 static int pca_xfer(struct i2c_adapter
*i2c_adap
,
169 struct i2c_msg
*msgs
,
172 struct i2c_algo_pca_data
*adap
= i2c_adap
->algo_data
;
173 struct i2c_msg
*msg
= NULL
;
179 unsigned long timeout
= jiffies
+ i2c_adap
->timeout
;
181 while ((state
= pca_status(adap
)) != 0xf8) {
182 if (time_before(jiffies
, timeout
)) {
185 dev_dbg(&i2c_adap
->dev
, "bus is not idle. status is "
191 DEB1("{{{ XFER %d messages\n", num
);
193 if (i2c_debug
>= 2) {
194 for (curmsg
= 0; curmsg
< num
; curmsg
++) {
198 addr
= (0x7f & msg
->addr
) ;
200 if (msg
->flags
& I2C_M_RD
)
201 printk(KERN_INFO
" [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
202 curmsg
, msg
->len
, addr
, (addr
<< 1) | 1);
204 printk(KERN_INFO
" [%02d] WR %d bytes to %#02x [%#02x%s",
205 curmsg
, msg
->len
, addr
, addr
<< 1,
206 msg
->len
== 0 ? "" : ", ");
207 for (i
= 0; i
< msg
->len
; i
++)
208 printk("%#04x%s", msg
->buf
[i
], i
== msg
->len
- 1 ? "" : ", ");
216 while (curmsg
< num
) {
217 state
= pca_status(adap
);
219 DEB3("STATE is 0x%02x\n", state
);
223 case 0xf8: /* On reset or stop the bus is idle */
224 completed
= pca_start(adap
);
227 case 0x08: /* A START condition has been transmitted */
228 case 0x10: /* A repeated start condition has been transmitted */
229 completed
= pca_address(adap
, msg
);
232 case 0x18: /* SLA+W has been transmitted; ACK has been received */
233 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
234 if (numbytes
< msg
->len
) {
235 completed
= pca_tx_byte(adap
,
240 curmsg
++; numbytes
= 0;
244 completed
= pca_repeated_start(adap
);
247 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
248 DEB2("NOT ACK received after SLA+W\n");
253 case 0x40: /* SLA+R has been transmitted; ACK has been received */
254 completed
= pca_rx_ack(adap
, msg
->len
> 1);
257 case 0x50: /* Data bytes has been received; ACK has been returned */
258 if (numbytes
< msg
->len
) {
259 pca_rx_byte(adap
, &msg
->buf
[numbytes
], 1);
261 completed
= pca_rx_ack(adap
,
262 numbytes
< msg
->len
- 1);
265 curmsg
++; numbytes
= 0;
269 completed
= pca_repeated_start(adap
);
272 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
273 DEB2("NOT ACK received after SLA+R\n");
278 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
279 DEB2("NOT ACK received after data byte\n");
283 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
284 DEB2("Arbitration lost\n");
286 * The PCA9564 data sheet (2006-09-01) says "A
287 * START condition will be transmitted when the
288 * bus becomes free (STOP or SCL and SDA high)"
289 * when the STA bit is set (p. 11).
291 * In case this won't work, try pca_reset()
297 case 0x58: /* Data byte has been received; NOT ACK has been returned */
298 if (numbytes
== msg
->len
- 1) {
299 pca_rx_byte(adap
, &msg
->buf
[numbytes
], 0);
300 curmsg
++; numbytes
= 0;
304 completed
= pca_repeated_start(adap
);
306 DEB2("NOT ACK sent after data byte received. "
307 "Not final byte. numbytes %d. len %d\n",
313 case 0x70: /* Bus error - SDA stuck low */
314 DEB2("BUS ERROR - SDA Stuck low\n");
317 case 0x90: /* Bus error - SCL stuck low */
318 DEB2("BUS ERROR - SCL Stuck low\n");
321 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
322 DEB2("BUS ERROR - Illegal START or STOP\n");
326 dev_err(&i2c_adap
->dev
, "unhandled SIO state 0x%02x\n", state
);
336 DEB1("}}} transferred %d/%d messages. "
337 "status is %#04x. control is %#04x\n",
338 curmsg
, num
, pca_status(adap
),
343 static u32
pca_func(struct i2c_adapter
*adap
)
345 return I2C_FUNC_I2C
| I2C_FUNC_SMBUS_EMUL
;
348 static const struct i2c_algorithm pca_algo
= {
349 .master_xfer
= pca_xfer
,
350 .functionality
= pca_func
,
353 static unsigned int pca_probe_chip(struct i2c_adapter
*adap
)
355 struct i2c_algo_pca_data
*pca_data
= adap
->algo_data
;
356 /* The trick here is to check if there is an indirect register
357 * available. If there is one, we will read the value we first
358 * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
359 * we wrote on I2C_PCA_ADR
361 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_IADR
);
362 pca_outw(pca_data
, I2C_PCA_IND
, 0xAA);
363 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_ITO
);
364 pca_outw(pca_data
, I2C_PCA_IND
, 0x00);
365 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_IADR
);
366 if (pca_inw(pca_data
, I2C_PCA_IND
) == 0xAA) {
367 printk(KERN_INFO
"%s: PCA9665 detected.\n", adap
->name
);
368 pca_data
->chip
= I2C_PCA_CHIP_9665
;
370 printk(KERN_INFO
"%s: PCA9564 detected.\n", adap
->name
);
371 pca_data
->chip
= I2C_PCA_CHIP_9564
;
373 return pca_data
->chip
;
376 static int pca_init(struct i2c_adapter
*adap
)
378 struct i2c_algo_pca_data
*pca_data
= adap
->algo_data
;
380 adap
->algo
= &pca_algo
;
382 if (pca_probe_chip(adap
) == I2C_PCA_CHIP_9564
) {
383 static int freqs
[] = {330, 288, 217, 146, 88, 59, 44, 36};
386 if (pca_data
->i2c_clock
> 7) {
387 switch (pca_data
->i2c_clock
) {
389 pca_data
->i2c_clock
= I2C_PCA_CON_330kHz
;
392 pca_data
->i2c_clock
= I2C_PCA_CON_288kHz
;
395 pca_data
->i2c_clock
= I2C_PCA_CON_217kHz
;
398 pca_data
->i2c_clock
= I2C_PCA_CON_146kHz
;
401 pca_data
->i2c_clock
= I2C_PCA_CON_88kHz
;
404 pca_data
->i2c_clock
= I2C_PCA_CON_59kHz
;
407 pca_data
->i2c_clock
= I2C_PCA_CON_44kHz
;
410 pca_data
->i2c_clock
= I2C_PCA_CON_36kHz
;
414 "%s: Invalid I2C clock speed selected."
415 " Using default 59kHz.\n", adap
->name
);
416 pca_data
->i2c_clock
= I2C_PCA_CON_59kHz
;
419 printk(KERN_WARNING
"%s: "
420 "Choosing the clock frequency based on "
421 "index is deprecated."
422 " Use the nominal frequency.\n", adap
->name
);
427 clock
= pca_clock(pca_data
);
428 printk(KERN_INFO
"%s: Clock frequency is %dkHz\n",
429 adap
->name
, freqs
[clock
]);
431 pca_set_con(pca_data
, I2C_PCA_CON_ENSIO
| clock
);
436 /* Values can be found on PCA9665 datasheet section 7.3.2.6 */
437 int min_tlow
, min_thi
;
438 /* These values are the maximum raise and fall values allowed
439 * by the I2C operation mode (Standard, Fast or Fast+)
440 * They are used (added) below to calculate the clock dividers
441 * of PCA9665. Note that they are slightly different of the
442 * real maximum, to allow the change on mode exactly on the
443 * maximum clock rate for each mode
447 if (pca_data
->i2c_clock
> 1265800) {
448 printk(KERN_WARNING
"%s: I2C clock speed too high."
449 " Using 1265.8kHz.\n", adap
->name
);
450 pca_data
->i2c_clock
= 1265800;
453 if (pca_data
->i2c_clock
< 60300) {
454 printk(KERN_WARNING
"%s: I2C clock speed too low."
455 " Using 60.3kHz.\n", adap
->name
);
456 pca_data
->i2c_clock
= 60300;
459 /* To avoid integer overflow, use clock/100 for calculations */
460 clock
= pca_clock(pca_data
) / 100;
462 if (pca_data
->i2c_clock
> I2C_MAX_FAST_MODE_PLUS_FREQ
) {
463 mode
= I2C_PCA_MODE_TURBO
;
466 raise_fall_time
= 22; /* Raise 11e-8s, Fall 11e-8s */
467 } else if (pca_data
->i2c_clock
> I2C_MAX_FAST_MODE_FREQ
) {
468 mode
= I2C_PCA_MODE_FASTP
;
471 raise_fall_time
= 22; /* Raise 11e-8s, Fall 11e-8s */
472 } else if (pca_data
->i2c_clock
> I2C_MAX_STANDARD_MODE_FREQ
) {
473 mode
= I2C_PCA_MODE_FAST
;
476 raise_fall_time
= 58; /* Raise 29e-8s, Fall 29e-8s */
478 mode
= I2C_PCA_MODE_STD
;
481 raise_fall_time
= 127; /* Raise 29e-8s, Fall 98e-8s */
484 /* The minimum clock that respects the thi/tlow = 134/157 is
485 * 64800 Hz. Below that, we have to fix the tlow to 255 and
486 * calculate the thi factor.
490 thi
= 1000000 - clock
* raise_fall_time
;
491 thi
/= (I2C_PCA_OSC_PER
* clock
) - tlow
;
493 tlow
= (1000000 - clock
* raise_fall_time
) * min_tlow
;
494 tlow
/= I2C_PCA_OSC_PER
* clock
* (min_thi
+ min_tlow
);
495 thi
= tlow
* min_thi
/ min_tlow
;
501 "%s: Clock frequency is %dHz\n", adap
->name
, clock
* 100);
503 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_IMODE
);
504 pca_outw(pca_data
, I2C_PCA_IND
, mode
);
505 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_ISCLL
);
506 pca_outw(pca_data
, I2C_PCA_IND
, tlow
);
507 pca_outw(pca_data
, I2C_PCA_INDPTR
, I2C_PCA_ISCLH
);
508 pca_outw(pca_data
, I2C_PCA_IND
, thi
);
510 pca_set_con(pca_data
, I2C_PCA_CON_ENSIO
);
512 udelay(500); /* 500 us for oscillator to stabilise */
518 * registering functions to load algorithms at runtime
520 int i2c_pca_add_bus(struct i2c_adapter
*adap
)
524 rval
= pca_init(adap
);
528 return i2c_add_adapter(adap
);
530 EXPORT_SYMBOL(i2c_pca_add_bus
);
532 int i2c_pca_add_numbered_bus(struct i2c_adapter
*adap
)
536 rval
= pca_init(adap
);
540 return i2c_add_numbered_adapter(adap
);
542 EXPORT_SYMBOL(i2c_pca_add_numbered_bus
);
544 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
545 "Wolfram Sang <kernel@pengutronix.de>");
546 MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
547 MODULE_LICENSE("GPL");
549 module_param(i2c_debug
, int, 0);