2 * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
3 * Copyright (C) 2004 Arcom Control Systems
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/delay.h>
24 #include <linux/slab.h>
25 #include <linux/init.h>
26 #include <linux/errno.h>
27 #include <linux/i2c.h>
28 #include <linux/i2c-algo-pca.h>
29 #include "i2c-algo-pca.h"
31 #define DRIVER "i2c-algo-pca"
33 #define DEB1(fmt, args...) do { if (i2c_debug>=1) printk(fmt, ## args); } while(0)
34 #define DEB2(fmt, args...) do { if (i2c_debug>=2) printk(fmt, ## args); } while(0)
35 #define DEB3(fmt, args...) do { if (i2c_debug>=3) printk(fmt, ## args); } while(0)
39 #define pca_outw(adap, reg, val) adap->write_byte(adap, reg, val)
40 #define pca_inw(adap, reg) adap->read_byte(adap, reg)
42 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
43 #define pca_clock(adap) adap->get_clock(adap)
44 #define pca_own(adap) adap->get_own(adap)
45 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
46 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
47 #define pca_wait(adap) adap->wait_for_interrupt(adap)
50 * Generate a start condition on the i2c bus.
52 * returns after the start condition has occurred
54 static void 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);
65 * Generate a repeated start condition on the i2c bus
67 * return after the repeated start condition has occurred
69 static void 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);
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 void pca_address(struct i2c_algo_pca_data *adap,
105 int sta = pca_get_con(adap);
108 addr = ( (0x7f & msg->addr) << 1 );
109 if (msg->flags & I2C_M_RD )
111 DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
112 msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
114 pca_outw(adap, I2C_PCA_DAT, addr);
116 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
117 pca_set_con(adap, sta);
125 * Returns after the byte has been transmitted
127 static void pca_tx_byte(struct i2c_algo_pca_data *adap,
130 int sta = pca_get_con(adap);
131 DEB2("=== WRITE %#04x\n", b);
132 pca_outw(adap, I2C_PCA_DAT, b);
134 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
135 pca_set_con(adap, sta);
143 * returns immediately.
145 static void pca_rx_byte(struct i2c_algo_pca_data *adap,
148 *b = pca_inw(adap, I2C_PCA_DAT);
149 DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
153 * Setup ACK or NACK for next received byte and wait for it to arrive.
155 * Returns after next byte has arrived.
157 static void pca_rx_ack(struct i2c_algo_pca_data *adap,
160 int sta = pca_get_con(adap);
162 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
165 sta |= I2C_PCA_CON_AA;
167 pca_set_con(adap, sta);
172 * Reset the i2c bus / SIO
174 static void pca_reset(struct i2c_algo_pca_data *adap)
176 /* apparently only an external reset will do it. not a lot can be done */
177 printk(KERN_ERR DRIVER ": Haven't figured out how to do a reset yet\n");
180 static int pca_xfer(struct i2c_adapter *i2c_adap,
181 struct i2c_msg *msgs,
184 struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
185 struct i2c_msg *msg = NULL;
192 while ((state = pca_status(adap)) != 0xf8 && timeout--) {
196 dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
200 DEB1("{{{ XFER %d messages\n", num);
203 for (curmsg = 0; curmsg < num; curmsg++) {
207 addr = (0x7f & msg->addr) ;
209 if (msg->flags & I2C_M_RD )
210 printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
211 curmsg, msg->len, addr, (addr<<1) | 1);
213 printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s",
214 curmsg, msg->len, addr, addr<<1,
215 msg->len == 0 ? "" : ", ");
216 for(i=0; i < msg->len; i++)
217 printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
225 while (curmsg < num) {
226 state = pca_status(adap);
228 DEB3("STATE is 0x%02x\n", state);
232 case 0xf8: /* On reset or stop the bus is idle */
236 case 0x08: /* A START condition has been transmitted */
237 case 0x10: /* A repeated start condition has been transmitted */
238 pca_address(adap, msg);
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) {
244 pca_tx_byte(adap, msg->buf[numbytes]);
248 curmsg++; numbytes = 0;
252 pca_repeated_start(adap);
255 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
256 DEB2("NOT ACK received after SLA+W\n");
260 case 0x40: /* SLA+R has been transmitted; ACK has been received */
261 pca_rx_ack(adap, msg->len > 1);
264 case 0x50: /* Data bytes has been received; ACK has been returned */
265 if (numbytes < msg->len) {
266 pca_rx_byte(adap, &msg->buf[numbytes], 1);
268 pca_rx_ack(adap, numbytes < msg->len - 1);
271 curmsg++; numbytes = 0;
275 pca_repeated_start(adap);
278 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
279 DEB2("NOT ACK received after SLA+R\n");
283 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
284 DEB2("NOT ACK received after data byte\n");
287 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
288 DEB2("Arbitration lost\n");
291 case 0x58: /* Data byte has been received; NOT ACK has been returned */
292 if ( numbytes == msg->len - 1 ) {
293 pca_rx_byte(adap, &msg->buf[numbytes], 0);
294 curmsg++; numbytes = 0;
298 pca_repeated_start(adap);
300 DEB2("NOT ACK sent after data byte received. "
301 "Not final byte. numbytes %d. len %d\n",
307 case 0x70: /* Bus error - SDA stuck low */
308 DEB2("BUS ERROR - SDA Stuck low\n");
311 case 0x90: /* Bus error - SCL stuck low */
312 DEB2("BUS ERROR - SCL Stuck low\n");
315 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
316 DEB2("BUS ERROR - Illegal START or STOP\n");
320 printk(KERN_ERR DRIVER ": unhandled SIO state 0x%02x\n", state);
328 DEB1(KERN_CRIT "}}} transfered %d/%d messages. "
329 "status is %#04x. control is %#04x\n",
330 curmsg, num, pca_status(adap),
335 static u32 pca_func(struct i2c_adapter *adap)
337 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
340 static int pca_init(struct i2c_algo_pca_data *adap)
342 static int freqs[] = {330,288,217,146,88,59,44,36};
346 clock = pca_clock(adap);
347 DEB1(KERN_INFO DRIVER ": own address is %#04x\n", own);
348 DEB1(KERN_INFO DRIVER ": clock freqeuncy is %dkHz\n", freqs[clock]);
350 pca_outw(adap, I2C_PCA_ADR, own << 1);
352 pca_set_con(adap, I2C_PCA_CON_ENSIO | clock);
353 udelay(500); /* 500 us for oscilator to stabilise */
358 static const struct i2c_algorithm pca_algo = {
359 .master_xfer = pca_xfer,
360 .functionality = pca_func,
364 * registering functions to load algorithms at runtime
366 int i2c_pca_add_bus(struct i2c_adapter *adap)
368 struct i2c_algo_pca_data *pca_adap = adap->algo_data;
371 /* register new adapter to i2c module... */
372 adap->algo = &pca_algo;
374 adap->timeout = 100; /* default values, should */
375 adap->retries = 3; /* be replaced by defines */
377 if ((rval = pca_init(pca_adap)))
380 rval = i2c_add_adapter(adap);
384 EXPORT_SYMBOL(i2c_pca_add_bus);
386 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
387 MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
388 MODULE_LICENSE("GPL");
390 module_param(i2c_debug, int, 0);