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1da177e4 LT |
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 | ||
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/kernel.h> | |
32 | #include <linux/module.h> | |
8b798c4d | 33 | #include <linux/platform_device.h> |
1da177e4 LT |
34 | #include <linux/init.h> |
35 | #include <linux/errno.h> | |
36 | #include <linux/i2c.h> | |
8b798c4d | 37 | #include <linux/slab.h> |
1da177e4 | 38 | |
a294de4e | 39 | #include <asm/mach-au1x00/au1xxx.h> |
1da177e4 LT |
40 | #include <asm/mach-au1x00/au1xxx_psc.h> |
41 | ||
8b798c4d ML |
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 | }; | |
1da177e4 LT |
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 | ||
a202707e | 59 | /* Wait for Tx Buffer Empty |
1da177e4 LT |
60 | */ |
61 | for (i = 0; i < adap->xfer_timeout; i++) { | |
a202707e | 62 | stat = sp->psc_smbstat; |
1da177e4 | 63 | au_sync(); |
a202707e | 64 | if ((stat & PSC_SMBSTAT_TE) != 0) |
1da177e4 | 65 | return 0; |
a202707e | 66 | |
1da177e4 LT |
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 | |
91f27958 | 116 | do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd, int q) |
1da177e4 LT |
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 | */ | |
8859942e | 125 | stat = sp->psc_smbstat; |
1da177e4 LT |
126 | sp->psc_smbevnt = PSC_SMBEVNT_ALLCLR; |
127 | au_sync(); | |
8859942e DP |
128 | |
129 | if (!(stat & PSC_SMBSTAT_TE) || !(stat & PSC_SMBSTAT_RE)) { | |
130 | sp->psc_smbpcr = PSC_SMBPCR_DC; | |
1da177e4 | 131 | au_sync(); |
8859942e DP |
132 | do { |
133 | stat = sp->psc_smbpcr; | |
134 | au_sync(); | |
135 | } while ((stat & PSC_SMBPCR_DC) != 0); | |
136 | udelay(50); | |
137 | } | |
1da177e4 LT |
138 | |
139 | /* Write out the i2c chip address and specify operation | |
140 | */ | |
141 | addr <<= 1; | |
142 | if (rd) | |
143 | addr |= 1; | |
144 | ||
91f27958 ML |
145 | /* zero-byte xfers stop immediately */ |
146 | if (q) | |
147 | addr |= PSC_SMBTXRX_STP; | |
148 | ||
1da177e4 LT |
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; | |
91f27958 | 157 | return (q) ? wait_master_done(adap) : 0; |
1da177e4 LT |
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 | struct i2c_msg *p; | |
273 | int i, err = 0; | |
274 | ||
275 | for (i = 0; !err && i < num; i++) { | |
276 | p = &msgs[i]; | |
91f27958 ML |
277 | err = do_address(adap, p->addr, p->flags & I2C_M_RD, |
278 | (p->len == 0)); | |
1da177e4 LT |
279 | if (err || !p->len) |
280 | continue; | |
281 | if (p->flags & I2C_M_RD) | |
282 | err = i2c_read(adap, p->buf, p->len); | |
283 | else | |
284 | err = i2c_write(adap, p->buf, p->len); | |
285 | } | |
286 | ||
287 | /* Return the number of messages processed, or the error code. | |
288 | */ | |
289 | if (err == 0) | |
290 | err = num; | |
291 | return err; | |
292 | } | |
293 | ||
294 | static u32 | |
295 | au1550_func(struct i2c_adapter *adap) | |
296 | { | |
6ed07134 | 297 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; |
1da177e4 LT |
298 | } |
299 | ||
8f9082c5 | 300 | static const struct i2c_algorithm au1550_algo = { |
1da177e4 LT |
301 | .master_xfer = au1550_xfer, |
302 | .functionality = au1550_func, | |
303 | }; | |
304 | ||
305 | /* | |
306 | * registering functions to load algorithms at runtime | |
307 | * Prior to calling us, the 50MHz clock frequency and routing | |
308 | * must have been set up for the PSC indicated by the adapter. | |
309 | */ | |
8b798c4d ML |
310 | static int __devinit |
311 | i2c_au1550_probe(struct platform_device *pdev) | |
1da177e4 | 312 | { |
8b798c4d ML |
313 | struct i2c_au1550_data *priv; |
314 | volatile psc_smb_t *sp; | |
315 | struct resource *r; | |
316 | u32 stat; | |
317 | int ret; | |
318 | ||
319 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
320 | if (!r) { | |
321 | ret = -ENODEV; | |
322 | goto out; | |
323 | } | |
1da177e4 | 324 | |
8b798c4d ML |
325 | priv = kzalloc(sizeof(struct i2c_au1550_data), GFP_KERNEL); |
326 | if (!priv) { | |
327 | ret = -ENOMEM; | |
328 | goto out; | |
329 | } | |
330 | ||
331 | priv->ioarea = request_mem_region(r->start, r->end - r->start + 1, | |
332 | pdev->name); | |
333 | if (!priv->ioarea) { | |
334 | ret = -EBUSY; | |
335 | goto out_mem; | |
336 | } | |
337 | ||
8e07c2c6 | 338 | priv->psc_base = CKSEG1ADDR(r->start); |
8b798c4d ML |
339 | priv->xfer_timeout = 200; |
340 | priv->ack_timeout = 200; | |
341 | ||
342 | priv->adap.id = I2C_HW_AU1550_PSC; | |
343 | priv->adap.nr = pdev->id; | |
344 | priv->adap.algo = &au1550_algo; | |
345 | priv->adap.algo_data = priv; | |
346 | priv->adap.dev.parent = &pdev->dev; | |
347 | strlcpy(priv->adap.name, "Au1xxx PSC I2C", sizeof(priv->adap.name)); | |
1da177e4 LT |
348 | |
349 | /* Now, set up the PSC for SMBus PIO mode. | |
350 | */ | |
8b798c4d | 351 | sp = (volatile psc_smb_t *)priv->psc_base; |
1da177e4 LT |
352 | sp->psc_ctrl = PSC_CTRL_DISABLE; |
353 | au_sync(); | |
354 | sp->psc_sel = PSC_SEL_PS_SMBUSMODE; | |
355 | sp->psc_smbcfg = 0; | |
356 | au_sync(); | |
357 | sp->psc_ctrl = PSC_CTRL_ENABLE; | |
358 | au_sync(); | |
359 | do { | |
360 | stat = sp->psc_smbstat; | |
361 | au_sync(); | |
362 | } while ((stat & PSC_SMBSTAT_SR) == 0); | |
363 | ||
364 | sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 | | |
365 | PSC_SMBCFG_DD_DISABLE); | |
366 | ||
367 | /* Divide by 8 to get a 6.25 MHz clock. The later protocol | |
368 | * timings are based on this clock. | |
369 | */ | |
370 | sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8); | |
371 | sp->psc_smbmsk = PSC_SMBMSK_ALLMASK; | |
372 | au_sync(); | |
373 | ||
374 | /* Set the protocol timer values. See Table 71 in the | |
375 | * Au1550 Data Book for standard timing values. | |
376 | */ | |
377 | sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \ | |
378 | PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \ | |
379 | PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \ | |
380 | PSC_SMBTMR_SET_CH(15); | |
381 | au_sync(); | |
382 | ||
383 | sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE; | |
384 | do { | |
385 | stat = sp->psc_smbstat; | |
386 | au_sync(); | |
387 | } while ((stat & PSC_SMBSTAT_DR) == 0); | |
388 | ||
8b798c4d ML |
389 | ret = i2c_add_numbered_adapter(&priv->adap); |
390 | if (ret == 0) { | |
391 | platform_set_drvdata(pdev, priv); | |
392 | return 0; | |
393 | } | |
394 | ||
395 | /* disable the PSC */ | |
396 | sp->psc_smbcfg = 0; | |
397 | sp->psc_ctrl = PSC_CTRL_DISABLE; | |
398 | au_sync(); | |
1da177e4 | 399 | |
8b798c4d ML |
400 | release_resource(priv->ioarea); |
401 | kfree(priv->ioarea); | |
402 | out_mem: | |
403 | kfree(priv); | |
404 | out: | |
405 | return ret; | |
406 | } | |
1da177e4 | 407 | |
8b798c4d ML |
408 | static int __devexit |
409 | i2c_au1550_remove(struct platform_device *pdev) | |
1da177e4 | 410 | { |
8b798c4d ML |
411 | struct i2c_au1550_data *priv = platform_get_drvdata(pdev); |
412 | volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base; | |
413 | ||
414 | platform_set_drvdata(pdev, NULL); | |
415 | i2c_del_adapter(&priv->adap); | |
416 | sp->psc_smbcfg = 0; | |
417 | sp->psc_ctrl = PSC_CTRL_DISABLE; | |
418 | au_sync(); | |
419 | release_resource(priv->ioarea); | |
420 | kfree(priv->ioarea); | |
421 | kfree(priv); | |
422 | return 0; | |
1da177e4 LT |
423 | } |
424 | ||
425 | static int | |
8b798c4d | 426 | i2c_au1550_suspend(struct platform_device *pdev, pm_message_t state) |
1da177e4 | 427 | { |
8b798c4d ML |
428 | struct i2c_au1550_data *priv = platform_get_drvdata(pdev); |
429 | volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base; | |
430 | ||
431 | sp->psc_ctrl = PSC_CTRL_SUSPEND; | |
432 | au_sync(); | |
1da177e4 LT |
433 | return 0; |
434 | } | |
435 | ||
436 | static int | |
8b798c4d | 437 | i2c_au1550_resume(struct platform_device *pdev) |
1da177e4 | 438 | { |
8b798c4d ML |
439 | struct i2c_au1550_data *priv = platform_get_drvdata(pdev); |
440 | volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base; | |
441 | ||
442 | sp->psc_ctrl = PSC_CTRL_ENABLE; | |
443 | au_sync(); | |
444 | while (!(sp->psc_smbstat & PSC_SMBSTAT_SR)) | |
445 | au_sync(); | |
1da177e4 LT |
446 | return 0; |
447 | } | |
448 | ||
8b798c4d ML |
449 | static struct platform_driver au1xpsc_smbus_driver = { |
450 | .driver = { | |
451 | .name = "au1xpsc_smbus", | |
452 | .owner = THIS_MODULE, | |
453 | }, | |
454 | .probe = i2c_au1550_probe, | |
455 | .remove = __devexit_p(i2c_au1550_remove), | |
456 | .suspend = i2c_au1550_suspend, | |
457 | .resume = i2c_au1550_resume, | |
1da177e4 LT |
458 | }; |
459 | ||
1da177e4 LT |
460 | static int __init |
461 | i2c_au1550_init(void) | |
462 | { | |
8b798c4d | 463 | return platform_driver_register(&au1xpsc_smbus_driver); |
1da177e4 LT |
464 | } |
465 | ||
466 | static void __exit | |
467 | i2c_au1550_exit(void) | |
468 | { | |
8b798c4d | 469 | platform_driver_unregister(&au1xpsc_smbus_driver); |
1da177e4 LT |
470 | } |
471 | ||
472 | MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC."); | |
473 | MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550"); | |
474 | MODULE_LICENSE("GPL"); | |
add8eda7 | 475 | MODULE_ALIAS("platform:au1xpsc_smbus"); |
1da177e4 LT |
476 | |
477 | module_init (i2c_au1550_init); | |
478 | module_exit (i2c_au1550_exit); |