Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / drivers / i2c / busses / i2c-au1550.c
1 /*
2  * i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface
3  * Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
4  *
5  * 2.6 port by Matt Porter <mporter@kernel.crashing.org>
6  *
7  * The documentation describes this as an SMBus controller, but it doesn't
8  * understand any of the SMBus protocol in hardware.  It's really an I2C
9  * controller that could emulate most of the SMBus in software.
10  *
11  * This is just a skeleton adapter to use with the Au1550 PSC
12  * algorithm.  It was developed for the Pb1550, but will work with
13  * any Au1550 board that has a similar PSC configuration.
14  *
15  * This program is free software; you can redistribute it and/or
16  * modify it under the terms of the GNU General Public License
17  * as published by the Free Software Foundation; either version 2
18  * of the License, or (at your option) any later version.
19  *
20  * This program is distributed in the hope that it will be useful,
21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
23  * GNU General Public License for more details.
24  *
25  * You should have received a copy of the GNU General Public License
26  * along with this program; if not, write to the Free Software
27  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
28  */
29
30 #include <linux/delay.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/platform_device.h>
34 #include <linux/init.h>
35 #include <linux/errno.h>
36 #include <linux/i2c.h>
37 #include <linux/slab.h>
38
39 #include <asm/mach-au1x00/au1xxx.h>
40 #include <asm/mach-au1x00/au1xxx_psc.h>
41
42 struct i2c_au1550_data {
43         u32     psc_base;
44         int     xfer_timeout;
45         int     ack_timeout;
46         struct i2c_adapter adap;
47         struct resource *ioarea;
48 };
49
50 static int
51 wait_xfer_done(struct i2c_au1550_data *adap)
52 {
53         u32     stat;
54         int     i;
55         volatile psc_smb_t      *sp;
56
57         sp = (volatile psc_smb_t *)(adap->psc_base);
58
59         /* Wait for Tx Buffer Empty
60         */
61         for (i = 0; i < adap->xfer_timeout; i++) {
62                 stat = sp->psc_smbstat;
63                 au_sync();
64                 if ((stat & PSC_SMBSTAT_TE) != 0)
65                         return 0;
66
67                 udelay(1);
68         }
69
70         return -ETIMEDOUT;
71 }
72
73 static int
74 wait_ack(struct i2c_au1550_data *adap)
75 {
76         u32     stat;
77         volatile psc_smb_t      *sp;
78
79         if (wait_xfer_done(adap))
80                 return -ETIMEDOUT;
81
82         sp = (volatile psc_smb_t *)(adap->psc_base);
83
84         stat = sp->psc_smbevnt;
85         au_sync();
86
87         if ((stat & (PSC_SMBEVNT_DN | PSC_SMBEVNT_AN | PSC_SMBEVNT_AL)) != 0)
88                 return -ETIMEDOUT;
89
90         return 0;
91 }
92
93 static int
94 wait_master_done(struct i2c_au1550_data *adap)
95 {
96         u32     stat;
97         int     i;
98         volatile psc_smb_t      *sp;
99
100         sp = (volatile psc_smb_t *)(adap->psc_base);
101
102         /* Wait for Master Done.
103         */
104         for (i = 0; i < adap->xfer_timeout; i++) {
105                 stat = sp->psc_smbevnt;
106                 au_sync();
107                 if ((stat & PSC_SMBEVNT_MD) != 0)
108                         return 0;
109                 udelay(1);
110         }
111
112         return -ETIMEDOUT;
113 }
114
115 static int
116 do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd, int q)
117 {
118         volatile psc_smb_t      *sp;
119         u32                     stat;
120
121         sp = (volatile psc_smb_t *)(adap->psc_base);
122
123         /* Reset the FIFOs, clear events.
124         */
125         stat = sp->psc_smbstat;
126         sp->psc_smbevnt = PSC_SMBEVNT_ALLCLR;
127         au_sync();
128
129         if (!(stat & PSC_SMBSTAT_TE) || !(stat & PSC_SMBSTAT_RE)) {
130                 sp->psc_smbpcr = PSC_SMBPCR_DC;
131                 au_sync();
132                 do {
133                         stat = sp->psc_smbpcr;
134                         au_sync();
135                 } while ((stat & PSC_SMBPCR_DC) != 0);
136                 udelay(50);
137         }
138
139         /* Write out the i2c chip address and specify operation
140         */
141         addr <<= 1;
142         if (rd)
143                 addr |= 1;
144
145         /* zero-byte xfers stop immediately */
146         if (q)
147                 addr |= PSC_SMBTXRX_STP;
148
149         /* Put byte into fifo, start up master.
150         */
151         sp->psc_smbtxrx = addr;
152         au_sync();
153         sp->psc_smbpcr = PSC_SMBPCR_MS;
154         au_sync();
155         if (wait_ack(adap))
156                 return -EIO;
157         return (q) ? wait_master_done(adap) : 0;
158 }
159
160 static u32
161 wait_for_rx_byte(struct i2c_au1550_data *adap, u32 *ret_data)
162 {
163         int     j;
164         u32     data, stat;
165         volatile psc_smb_t      *sp;
166
167         if (wait_xfer_done(adap))
168                 return -EIO;
169
170         sp = (volatile psc_smb_t *)(adap->psc_base);
171
172         j =  adap->xfer_timeout * 100;
173         do {
174                 j--;
175                 if (j <= 0)
176                         return -EIO;
177
178                 stat = sp->psc_smbstat;
179                 au_sync();
180                 if ((stat & PSC_SMBSTAT_RE) == 0)
181                         j = 0;
182                 else
183                         udelay(1);
184         } while (j > 0);
185         data = sp->psc_smbtxrx;
186         au_sync();
187         *ret_data = data;
188
189         return 0;
190 }
191
192 static int
193 i2c_read(struct i2c_au1550_data *adap, unsigned char *buf,
194                     unsigned int len)
195 {
196         int     i;
197         u32     data;
198         volatile psc_smb_t      *sp;
199
200         if (len == 0)
201                 return 0;
202
203         /* A read is performed by stuffing the transmit fifo with
204          * zero bytes for timing, waiting for bytes to appear in the
205          * receive fifo, then reading the bytes.
206          */
207
208         sp = (volatile psc_smb_t *)(adap->psc_base);
209
210         i = 0;
211         while (i < (len-1)) {
212                 sp->psc_smbtxrx = 0;
213                 au_sync();
214                 if (wait_for_rx_byte(adap, &data))
215                         return -EIO;
216
217                 buf[i] = data;
218                 i++;
219         }
220
221         /* The last byte has to indicate transfer done.
222         */
223         sp->psc_smbtxrx = PSC_SMBTXRX_STP;
224         au_sync();
225         if (wait_master_done(adap))
226                 return -EIO;
227
228         data = sp->psc_smbtxrx;
229         au_sync();
230         buf[i] = data;
231         return 0;
232 }
233
234 static int
235 i2c_write(struct i2c_au1550_data *adap, unsigned char *buf,
236                      unsigned int len)
237 {
238         int     i;
239         u32     data;
240         volatile psc_smb_t      *sp;
241
242         if (len == 0)
243                 return 0;
244
245         sp = (volatile psc_smb_t *)(adap->psc_base);
246
247         i = 0;
248         while (i < (len-1)) {
249                 data = buf[i];
250                 sp->psc_smbtxrx = data;
251                 au_sync();
252                 if (wait_ack(adap))
253                         return -EIO;
254                 i++;
255         }
256
257         /* The last byte has to indicate transfer done.
258         */
259         data = buf[i];
260         data |= PSC_SMBTXRX_STP;
261         sp->psc_smbtxrx = data;
262         au_sync();
263         if (wait_master_done(adap))
264                 return -EIO;
265         return 0;
266 }
267
268 static int
269 au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
270 {
271         struct i2c_au1550_data *adap = i2c_adap->algo_data;
272         volatile psc_smb_t *sp = (volatile psc_smb_t *)adap->psc_base;
273         struct i2c_msg *p;
274         int i, err = 0;
275
276         sp->psc_ctrl = PSC_CTRL_ENABLE;
277         au_sync();
278
279         for (i = 0; !err && i < num; i++) {
280                 p = &msgs[i];
281                 err = do_address(adap, p->addr, p->flags & I2C_M_RD,
282                                  (p->len == 0));
283                 if (err || !p->len)
284                         continue;
285                 if (p->flags & I2C_M_RD)
286                         err = i2c_read(adap, p->buf, p->len);
287                 else
288                         err = i2c_write(adap, p->buf, p->len);
289         }
290
291         /* Return the number of messages processed, or the error code.
292         */
293         if (err == 0)
294                 err = num;
295
296         sp->psc_ctrl = PSC_CTRL_SUSPEND;
297         au_sync();
298
299         return err;
300 }
301
302 static u32
303 au1550_func(struct i2c_adapter *adap)
304 {
305         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
306 }
307
308 static const struct i2c_algorithm au1550_algo = {
309         .master_xfer    = au1550_xfer,
310         .functionality  = au1550_func,
311 };
312
313 static void i2c_au1550_setup(struct i2c_au1550_data *priv)
314 {
315         volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
316         u32 stat;
317
318         sp->psc_ctrl = PSC_CTRL_DISABLE;
319         au_sync();
320         sp->psc_sel = PSC_SEL_PS_SMBUSMODE;
321         sp->psc_smbcfg = 0;
322         au_sync();
323         sp->psc_ctrl = PSC_CTRL_ENABLE;
324         au_sync();
325         do {
326                 stat = sp->psc_smbstat;
327                 au_sync();
328         } while ((stat & PSC_SMBSTAT_SR) == 0);
329
330         sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 |
331                                 PSC_SMBCFG_DD_DISABLE);
332
333         /* Divide by 8 to get a 6.25 MHz clock.  The later protocol
334          * timings are based on this clock.
335          */
336         sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
337         sp->psc_smbmsk = PSC_SMBMSK_ALLMASK;
338         au_sync();
339
340         /* Set the protocol timer values.  See Table 71 in the
341          * Au1550 Data Book for standard timing values.
342          */
343         sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \
344                 PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \
345                 PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \
346                 PSC_SMBTMR_SET_CH(15);
347         au_sync();
348
349         sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE;
350         do {
351                 stat = sp->psc_smbstat;
352                 au_sync();
353         } while ((stat & PSC_SMBSTAT_SR) == 0);
354
355         sp->psc_ctrl = PSC_CTRL_SUSPEND;
356         au_sync();
357 }
358
359 static void i2c_au1550_disable(struct i2c_au1550_data *priv)
360 {
361         volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
362
363         sp->psc_smbcfg = 0;
364         sp->psc_ctrl = PSC_CTRL_DISABLE;
365         au_sync();
366 }
367
368 /*
369  * registering functions to load algorithms at runtime
370  * Prior to calling us, the 50MHz clock frequency and routing
371  * must have been set up for the PSC indicated by the adapter.
372  */
373 static int __devinit
374 i2c_au1550_probe(struct platform_device *pdev)
375 {
376         struct i2c_au1550_data *priv;
377         struct resource *r;
378         int ret;
379
380         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
381         if (!r) {
382                 ret = -ENODEV;
383                 goto out;
384         }
385
386         priv = kzalloc(sizeof(struct i2c_au1550_data), GFP_KERNEL);
387         if (!priv) {
388                 ret = -ENOMEM;
389                 goto out;
390         }
391
392         priv->ioarea = request_mem_region(r->start, r->end - r->start + 1,
393                                           pdev->name);
394         if (!priv->ioarea) {
395                 ret = -EBUSY;
396                 goto out_mem;
397         }
398
399         priv->psc_base = CKSEG1ADDR(r->start);
400         priv->xfer_timeout = 200;
401         priv->ack_timeout = 200;
402
403         priv->adap.id = I2C_HW_AU1550_PSC;
404         priv->adap.nr = pdev->id;
405         priv->adap.algo = &au1550_algo;
406         priv->adap.algo_data = priv;
407         priv->adap.dev.parent = &pdev->dev;
408         strlcpy(priv->adap.name, "Au1xxx PSC I2C", sizeof(priv->adap.name));
409
410         /* Now, set up the PSC for SMBus PIO mode.
411         */
412         i2c_au1550_setup(priv);
413
414         ret = i2c_add_numbered_adapter(&priv->adap);
415         if (ret == 0) {
416                 platform_set_drvdata(pdev, priv);
417                 return 0;
418         }
419
420         i2c_au1550_disable(priv);
421
422         release_resource(priv->ioarea);
423         kfree(priv->ioarea);
424 out_mem:
425         kfree(priv);
426 out:
427         return ret;
428 }
429
430 static int __devexit
431 i2c_au1550_remove(struct platform_device *pdev)
432 {
433         struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
434
435         platform_set_drvdata(pdev, NULL);
436         i2c_del_adapter(&priv->adap);
437         i2c_au1550_disable(priv);
438         release_resource(priv->ioarea);
439         kfree(priv->ioarea);
440         kfree(priv);
441         return 0;
442 }
443
444 #ifdef CONFIG_PM
445 static int
446 i2c_au1550_suspend(struct platform_device *pdev, pm_message_t state)
447 {
448         struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
449
450         i2c_au1550_disable(priv);
451
452         return 0;
453 }
454
455 static int
456 i2c_au1550_resume(struct platform_device *pdev)
457 {
458         struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
459
460         i2c_au1550_setup(priv);
461
462         return 0;
463 }
464 #else
465 #define i2c_au1550_suspend      NULL
466 #define i2c_au1550_resume       NULL
467 #endif
468
469 static struct platform_driver au1xpsc_smbus_driver = {
470         .driver = {
471                 .name   = "au1xpsc_smbus",
472                 .owner  = THIS_MODULE,
473         },
474         .probe          = i2c_au1550_probe,
475         .remove         = __devexit_p(i2c_au1550_remove),
476         .suspend        = i2c_au1550_suspend,
477         .resume         = i2c_au1550_resume,
478 };
479
480 static int __init
481 i2c_au1550_init(void)
482 {
483         return platform_driver_register(&au1xpsc_smbus_driver);
484 }
485
486 static void __exit
487 i2c_au1550_exit(void)
488 {
489         platform_driver_unregister(&au1xpsc_smbus_driver);
490 }
491
492 MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC.");
493 MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550");
494 MODULE_LICENSE("GPL");
495 MODULE_ALIAS("platform:au1xpsc_smbus");
496
497 module_init (i2c_au1550_init);
498 module_exit (i2c_au1550_exit);