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1da177e4 LT |
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 | * | |
44bbe87e | 52 | * returns after the start condition has occurred |
1da177e4 LT |
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 | /* | |
46b615f4 | 65 | * Generate a repeated start condition on the i2c bus |
1da177e4 | 66 | * |
44bbe87e | 67 | * return after the repeated start condition has occurred |
1da177e4 LT |
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 | |
46b615f4 | 85 | * part returns the idle state (0xf8). Hence we don't need to |
1da177e4 LT |
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 |