?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Linux-2.6.12-rc2
[linux-2.6/kvm.git] / drivers / i2c / algos / i2c-algo-pca.c
blobc3d912cbbbc339435cc1a57aa2c29b5e6bbbb210
1 /*
2 * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
3 * Copyright (C) 2004 Arcom Control Systems
4 *
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.
9 *
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.
14 *
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.
18 */
19
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"
30
31 #define DRIVER "i2c-algo-pca"
32
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)
36
37 static int i2c_debug=0;
38
39 #define pca_outw(adap, reg, val) adap->write_byte(adap, reg, val)
40 #define pca_inw(adap, reg) adap->read_byte(adap, reg)
41
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)
48
49 /*
50 * Generate a start condition on the i2c bus.
51 *
52 * returns after the start condition has occured
53 */
54 static void pca_start(struct i2c_algo_pca_data *adap)
55 {
56 int sta = pca_get_con(adap);
57 DEB2("=== START\n");
58 sta |= I2C_PCA_CON_STA;
59 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
60 pca_set_con(adap, sta);
61 pca_wait(adap);
62 }
63
64 /*
65 * Generate a repeated start condition on the i2c bus
66 *
67 * return after the repeated start condition has occured
68 */
69 static void pca_repeated_start(struct i2c_algo_pca_data *adap)
70 {
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 pca_wait(adap);
77 }
78
79 /*
80 * Generate a stop condition on the i2c bus
81 *
82 * returns after the stop condition has been generated
83 *
84 * STOPs do not generate an interrupt or set the SI flag, since the
85 * part returns the the idle state (0xf8). Hence we don't need to
86 * pca_wait here.
87 */
88 static void pca_stop(struct i2c_algo_pca_data *adap)
89 {
90 int sta = pca_get_con(adap);
91 DEB2("=== STOP\n");
92 sta |= I2C_PCA_CON_STO;
93 sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
94 pca_set_con(adap, sta);
95 }
96
97 /*
98 * Send the slave address and R/W bit
99 *
100 * returns after the address has been sent
101 */
102 static void pca_address(struct i2c_algo_pca_data *adap,
103 struct i2c_msg *msg)
104 {
105 int sta = pca_get_con(adap);
106 int addr;
107
108 addr = ( (0x7f & msg->addr) << 1 );
109 if (msg->flags & I2C_M_RD )
110 addr |= 1;
111 DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
112 msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
113
114 pca_outw(adap, I2C_PCA_DAT, addr);
115
116 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
117 pca_set_con(adap, sta);
118
119 pca_wait(adap);
120 }
121
122 /*
123 * Transmit a byte.
124 *
125 * Returns after the byte has been transmitted
126 */
127 static void pca_tx_byte(struct i2c_algo_pca_data *adap,
128 __u8 b)
129 {
130 int sta = pca_get_con(adap);
131 DEB2("=== WRITE %#04x\n", b);
132 pca_outw(adap, I2C_PCA_DAT, b);
133
134 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
135 pca_set_con(adap, sta);
136
137 pca_wait(adap);
138 }
139
140 /*
141 * Receive a byte
142 *
143 * returns immediately.
144 */
145 static void pca_rx_byte(struct i2c_algo_pca_data *adap,
146 __u8 *b, int ack)
147 {
148 *b = pca_inw(adap, I2C_PCA_DAT);
149 DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
150 }
151
152 /*
153 * Setup ACK or NACK for next received byte and wait for it to arrive.
154 *
155 * Returns after next byte has arrived.
156 */
157 static void pca_rx_ack(struct i2c_algo_pca_data *adap,
158 int ack)
159 {
160 int sta = pca_get_con(adap);
161
162 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
163
164 if ( ack )
165 sta |= I2C_PCA_CON_AA;
166
167 pca_set_con(adap, sta);
168 pca_wait(adap);
169 }
170
171 /*
172 * Reset the i2c bus / SIO
173 */
174 static void pca_reset(struct i2c_algo_pca_data *adap)
175 {
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");
178 }
179
180 static int pca_xfer(struct i2c_adapter *i2c_adap,
181 struct i2c_msg *msgs,
182 int num)
183 {
184 struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
185 struct i2c_msg *msg = NULL;
186 int curmsg;
187 int numbytes = 0;
188 int state;
189 int ret;
190
191 state = pca_status(adap);
192 if ( state != 0xF8 ) {
193 dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state );
194 /* FIXME: what to do. Force stop ? */
195 return -EREMOTEIO;
196 }
197
198 DEB1("{{{ XFER %d messages\n", num);
199
200 if (i2c_debug>=2) {
201 for (curmsg = 0; curmsg < num; curmsg++) {
202 int addr, i;
203 msg = &msgs[curmsg];
204
205 addr = (0x7f & msg->addr) ;
206
207 if (msg->flags & I2C_M_RD )
208 printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
209 curmsg, msg->len, addr, (addr<<1) | 1);
210 else {
211 printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s",
212 curmsg, msg->len, addr, addr<<1,
213 msg->len == 0 ? "" : ", ");
214 for(i=0; i < msg->len; i++)
215 printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
216 printk("]\n");
217 }
218 }
219 }
220
221 curmsg = 0;
222 ret = -EREMOTEIO;
223 while (curmsg < num) {
224 state = pca_status(adap);
225
226 DEB3("STATE is 0x%02x\n", state);
227 msg = &msgs[curmsg];
228
229 switch (state) {
230 case 0xf8: /* On reset or stop the bus is idle */
231 pca_start(adap);
232 break;
233
234 case 0x08: /* A START condition has been transmitted */
235 case 0x10: /* A repeated start condition has been transmitted */
236 pca_address(adap, msg);
237 break;
238
239 case 0x18: /* SLA+W has been transmitted; ACK has been received */
240 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
241 if (numbytes < msg->len) {
242 pca_tx_byte(adap, msg->buf[numbytes]);
243 numbytes++;
244 break;
245 }
246 curmsg++; numbytes = 0;
247 if (curmsg == num)
248 pca_stop(adap);
249 else
250 pca_repeated_start(adap);
251 break;
252
253 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
254 DEB2("NOT ACK received after SLA+W\n");
255 pca_stop(adap);
256 goto out;
257
258 case 0x40: /* SLA+R has been transmitted; ACK has been received */
259 pca_rx_ack(adap, msg->len > 1);
260 break;
261
262 case 0x50: /* Data bytes has been received; ACK has been returned */
263 if (numbytes < msg->len) {
264 pca_rx_byte(adap, &msg->buf[numbytes], 1);
265 numbytes++;
266 pca_rx_ack(adap, numbytes < msg->len - 1);
267 break;
268 }
269 curmsg++; numbytes = 0;
270 if (curmsg == num)
271 pca_stop(adap);
272 else
273 pca_repeated_start(adap);
274 break;
275
276 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
277 DEB2("NOT ACK received after SLA+R\n");
278 pca_stop(adap);
279 goto out;
280
281 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
282 DEB2("NOT ACK received after data byte\n");
283 goto out;
284
285 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
286 DEB2("Arbitration lost\n");
287 goto out;
288
289 case 0x58: /* Data byte has been received; NOT ACK has been returned */
290 if ( numbytes == msg->len - 1 ) {
291 pca_rx_byte(adap, &msg->buf[numbytes], 0);
292 curmsg++; numbytes = 0;
293 if (curmsg == num)
294 pca_stop(adap);
295 else
296 pca_repeated_start(adap);
297 } else {
298 DEB2("NOT ACK sent after data byte received. "
299 "Not final byte. numbytes %d. len %d\n",
300 numbytes, msg->len);
301 pca_stop(adap);
302 goto out;
303 }
304 break;
305 case 0x70: /* Bus error - SDA stuck low */
306 DEB2("BUS ERROR - SDA Stuck low\n");
307 pca_reset(adap);
308 goto out;
309 case 0x90: /* Bus error - SCL stuck low */
310 DEB2("BUS ERROR - SCL Stuck low\n");
311 pca_reset(adap);
312 goto out;
313 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
314 DEB2("BUS ERROR - Illegal START or STOP\n");
315 pca_reset(adap);
316 goto out;
317 default:
318 printk(KERN_ERR DRIVER ": unhandled SIO state 0x%02x\n", state);
319 break;
320 }
321
322 }
323
324 ret = curmsg;
325 out:
326 DEB1(KERN_CRIT "}}} transfered %d/%d messages. "
327 "status is %#04x. control is %#04x\n",
328 curmsg, num, pca_status(adap),
329 pca_get_con(adap));
330 return ret;
331 }
332
333 static u32 pca_func(struct i2c_adapter *adap)
334 {
335 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
336 }
337
338 static int pca_init(struct i2c_algo_pca_data *adap)
339 {
340 static int freqs[] = {330,288,217,146,88,59,44,36};
341 int own, clock;
342
343 own = pca_own(adap);
344 clock = pca_clock(adap);
345 DEB1(KERN_INFO DRIVER ": own address is %#04x\n", own);
346 DEB1(KERN_INFO DRIVER ": clock freqeuncy is %dkHz\n", freqs[clock]);
347
348 pca_outw(adap, I2C_PCA_ADR, own << 1);
349
350 pca_set_con(adap, I2C_PCA_CON_ENSIO | clock);
351 udelay(500); /* 500 µs for oscilator to stabilise */
352
353 return 0;
354 }
355
356 static struct i2c_algorithm pca_algo = {
357 .name = "PCA9564 algorithm",
358 .id = I2C_ALGO_PCA,
359 .master_xfer = pca_xfer,
360 .functionality = pca_func,
361 };
362
363 /*
364 * registering functions to load algorithms at runtime
365 */
366 int i2c_pca_add_bus(struct i2c_adapter *adap)
367 {
368 struct i2c_algo_pca_data *pca_adap = adap->algo_data;
369 int rval;
370
371 /* register new adapter to i2c module... */
372
373 adap->id |= pca_algo.id;
374 adap->algo = &pca_algo;
375
376 adap->timeout = 100; /* default values, should */
377 adap->retries = 3; /* be replaced by defines */
378
379 rval = pca_init(pca_adap);
380
381 if (!rval)
382 i2c_add_adapter(adap);
383
384 return rval;
385 }
386
387 int i2c_pca_del_bus(struct i2c_adapter *adap)
388 {
389 return i2c_del_adapter(adap);
390 }
391
392 EXPORT_SYMBOL(i2c_pca_add_bus);
393 EXPORT_SYMBOL(i2c_pca_del_bus);
394
395 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
396 MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
397 MODULE_LICENSE("GPL");
398
399 module_param(i2c_debug, int, 0);
kernel-based virtual machine