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/drivers/i2c/algos/i2c-algo-pca.c

https://bitbucket.org/evzijst/gittest
C | 399 lines | 272 code | 61 blank | 66 comment | 28 complexity | f1ecf5547218fb05b7250b47fb571336 MD5 | raw file
  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
 37static 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 */
 54static 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 */
 69static 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 */
 88static 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 */
102static 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 */
127static 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 */
145static 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 */
157static 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 */
174static 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
180static 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
333static u32 pca_func(struct i2c_adapter *adap)
334{
335        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
336}
337
338static 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 �s for oscilator to stabilise */
352
353	return 0;
354}
355
356static 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 */
366int 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
387int i2c_pca_del_bus(struct i2c_adapter *adap)
388{
389	return i2c_del_adapter(adap);
390}
391
392EXPORT_SYMBOL(i2c_pca_add_bus);
393EXPORT_SYMBOL(i2c_pca_del_bus);
394
395MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
396MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
397MODULE_LICENSE("GPL");
398
399module_param(i2c_debug, int, 0);