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8#include <linux/delay.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/spinlock.h>
12#include <linux/platform_device.h>
13#include <linux/init.h>
14#include <linux/errno.h>
15#include <linux/i2c.h>
16#include <linux/slab.h>
17
18#define PIC32_I2CxCON 0x0000
19#define PIC32_I2CxCONCLR 0x0004
20#define PIC32_I2CxCONSET 0x0008
21#define PIC32_I2CxCONINV 0x000C
22#define I2CCON_ON (1<<15)
23#define I2CCON_FRZ (1<<14)
24#define I2CCON_SIDL (1<<13)
25#define I2CCON_SCLREL (1<<12)
26#define I2CCON_STRICT (1<<11)
27#define I2CCON_A10M (1<<10)
28#define I2CCON_DISSLW (1<<9)
29#define I2CCON_SMEN (1<<8)
30#define I2CCON_GCEN (1<<7)
31#define I2CCON_STREN (1<<6)
32#define I2CCON_ACKDT (1<<5)
33#define I2CCON_ACKEN (1<<4)
34#define I2CCON_RCEN (1<<3)
35#define I2CCON_PEN (1<<2)
36#define I2CCON_RSEN (1<<1)
37#define I2CCON_SEN (1<<0)
38
39#define PIC32_I2CxSTAT 0x0010
40#define PIC32_I2CxSTATCLR 0x0014
41#define PIC32_I2CxSTATSET 0x0018
42#define PIC32_I2CxSTATINV 0x001C
43#define I2CSTAT_ACKSTAT (1<<15)
44#define I2CSTAT_TRSTAT (1<<14)
45#define I2CSTAT_BCL (1<<10)
46#define I2CSTAT_GCSTAT (1<<9)
47#define I2CSTAT_ADD10 (1<<8)
48#define I2CSTAT_IWCOL (1<<7)
49#define I2CSTAT_I2COV (1<<6)
50#define I2CSTAT_DA (1<<5)
51#define I2CSTAT_P (1<<4)
52#define I2CSTAT_S (1<<3)
53#define I2CSTAT_RW (1<<2)
54#define I2CSTAT_RBF (1<<1)
55#define I2CSTAT_TBF (1<<0)
56
57#define PIC32_I2CxADD 0x0020
58#define PIC32_I2CxADDCLR 0x0024
59#define PIC32_I2CxADDSET 0x0028
60#define PIC32_I2CxADDINV 0x002C
61#define PIC32_I2CxMSK 0x0030
62#define PIC32_I2CxMSKCLR 0x0034
63#define PIC32_I2CxMSKSET 0x0038
64#define PIC32_I2CxMSKINV 0x003C
65#define PIC32_I2CxBRG 0x0040
66#define PIC32_I2CxBRGCLR 0x0044
67#define PIC32_I2CxBRGSET 0x0048
68#define PIC32_I2CxBRGINV 0x004C
69#define PIC32_I2CxTRN 0x0050
70#define PIC32_I2CxTRNCLR 0x0054
71#define PIC32_I2CxTRNSET 0x0058
72#define PIC32_I2CxTRNINV 0x005C
73#define PIC32_I2CxRCV 0x0060
74
75struct i2c_platform_data {
76 u32 base;
77 struct i2c_adapter adap;
78 u32 xfer_timeout;
79 u32 ack_timeout;
80 u32 ctl_timeout;
81};
82
83extern u32 pic32_bus_readl(u32 reg);
84extern void pic32_bus_writel(u32 val, u32 reg);
85
86static inline void
87StartI2C(struct i2c_platform_data *adap)
88{
89 pr_debug("StartI2C\n");
90 pic32_bus_writel(I2CCON_SEN, adap->base + PIC32_I2CxCONSET);
91}
92
93static inline void
94StopI2C(struct i2c_platform_data *adap)
95{
96 pr_debug("StopI2C\n");
97 pic32_bus_writel(I2CCON_PEN, adap->base + PIC32_I2CxCONSET);
98}
99
100static inline void
101AckI2C(struct i2c_platform_data *adap)
102{
103 pr_debug("AckI2C\n");
104 pic32_bus_writel(I2CCON_ACKDT, adap->base + PIC32_I2CxCONCLR);
105 pic32_bus_writel(I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
106}
107
108static inline void
109NotAckI2C(struct i2c_platform_data *adap)
110{
111 pr_debug("NakI2C\n");
112 pic32_bus_writel(I2CCON_ACKDT, adap->base + PIC32_I2CxCONSET);
113 pic32_bus_writel(I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
114}
115
116static inline int
117IdleI2C(struct i2c_platform_data *adap)
118{
119 int i;
120
121 pr_debug("IdleI2C\n");
122 for (i = 0; i < adap->ctl_timeout; i++) {
123 if (((pic32_bus_readl(adap->base + PIC32_I2CxCON) &
124 (I2CCON_ACKEN | I2CCON_RCEN | I2CCON_PEN | I2CCON_RSEN |
125 I2CCON_SEN)) == 0) &&
126 ((pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
127 (I2CSTAT_TRSTAT)) == 0))
128 return 0;
129 udelay(1);
130 }
131 return -ETIMEDOUT;
132}
133
134static inline u32
135MasterWriteI2C(struct i2c_platform_data *adap, u32 byte)
136{
137 pr_debug("MasterWriteI2C\n");
138
139 pic32_bus_writel(byte, adap->base + PIC32_I2CxTRN);
140
141 return pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & I2CSTAT_IWCOL;
142}
143
144static inline u32
145MasterReadI2C(struct i2c_platform_data *adap)
146{
147 pr_debug("MasterReadI2C\n");
148
149 pic32_bus_writel(I2CCON_RCEN, adap->base + PIC32_I2CxCONSET);
150
151 while (pic32_bus_readl(adap->base + PIC32_I2CxCON) & I2CCON_RCEN)
152 ;
153
154 pic32_bus_writel(I2CSTAT_I2COV, adap->base + PIC32_I2CxSTATCLR);
155
156 return pic32_bus_readl(adap->base + PIC32_I2CxRCV);
157}
158
159static int
160do_address(struct i2c_platform_data *adap, unsigned int addr, int rd)
161{
162 pr_debug("doaddress\n");
163
164 IdleI2C(adap);
165 StartI2C(adap);
166 IdleI2C(adap);
167
168 addr <<= 1;
169 if (rd)
170 addr |= 1;
171
172 if (MasterWriteI2C(adap, addr))
173 return -EIO;
174 IdleI2C(adap);
175 if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & I2CSTAT_ACKSTAT)
176 return -EIO;
177 return 0;
178}
179
180static int
181i2c_read(struct i2c_platform_data *adap, unsigned char *buf,
182 unsigned int len)
183{
184 int i;
185 u32 data;
186
187 pr_debug("i2c_read\n");
188
189 i = 0;
190 while (i < len) {
191 data = MasterReadI2C(adap);
192 buf[i++] = data;
193 if (i < len)
194 AckI2C(adap);
195 else
196 NotAckI2C(adap);
197 }
198
199 StopI2C(adap);
200 IdleI2C(adap);
201 return 0;
202}
203
204static int
205i2c_write(struct i2c_platform_data *adap, unsigned char *buf,
206 unsigned int len)
207{
208 int i;
209 u32 data;
210
211 pr_debug("i2c_write\n");
212
213 i = 0;
214 while (i < len) {
215 data = buf[i];
216 if (MasterWriteI2C(adap, data))
217 return -EIO;
218 IdleI2C(adap);
219 if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
220 I2CSTAT_ACKSTAT)
221 return -EIO;
222 i++;
223 }
224
225 StopI2C(adap);
226 IdleI2C(adap);
227 return 0;
228}
229
230static int
231platform_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
232{
233 struct i2c_platform_data *adap = i2c_adap->algo_data;
234 struct i2c_msg *p;
235 int i, err = 0;
236
237 pr_debug("platform_xfer\n");
238 for (i = 0; i < num; i++) {
239#define __BUFSIZE 80
240 int ii;
241 static char buf[__BUFSIZE];
242 char *b = buf;
243
244 p = &msgs[i];
245 b += sprintf(buf, " [%d bytes]", p->len);
246 if ((p->flags & I2C_M_RD) == 0) {
247 for (ii = 0; ii < p->len; ii++) {
248 if (b < &buf[__BUFSIZE-4]) {
249 b += sprintf(b, " %02x", p->buf[ii]);
250 } else {
251 strcat(b, "...");
252 break;
253 }
254 }
255 }
256 pr_debug("xfer%d: DevAddr: %04x Op:%s Data:%s\n", i, p->addr,
257 (p->flags & I2C_M_RD) ? "Rd" : "Wr", buf);
258 }
259
260
261 for (i = 0; !err && i < num; i++) {
262 p = &msgs[i];
263 err = do_address(adap, p->addr, p->flags & I2C_M_RD);
264 if (err || !p->len)
265 continue;
266 if (p->flags & I2C_M_RD)
267 err = i2c_read(adap, p->buf, p->len);
268 else
269 err = i2c_write(adap, p->buf, p->len);
270 }
271
272
273 if (err == 0)
274 err = num;
275
276 return err;
277}
278
279static u32
280platform_func(struct i2c_adapter *adap)
281{
282 pr_debug("platform_algo\n");
283 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
284}
285
286static const struct i2c_algorithm platform_algo = {
287 .master_xfer = platform_xfer,
288 .functionality = platform_func,
289};
290
291static void i2c_platform_setup(struct i2c_platform_data *priv)
292{
293 pr_debug("i2c_platform_setup\n");
294
295 pic32_bus_writel(500, priv->base + PIC32_I2CxBRG);
296 pic32_bus_writel(I2CCON_ON, priv->base + PIC32_I2CxCONCLR);
297 pic32_bus_writel(I2CCON_ON, priv->base + PIC32_I2CxCONSET);
298 pic32_bus_writel((I2CSTAT_BCL | I2CSTAT_IWCOL),
299 (priv->base + PIC32_I2CxSTATCLR));
300}
301
302static void i2c_platform_disable(struct i2c_platform_data *priv)
303{
304 pr_debug("i2c_platform_disable\n");
305}
306
307static int i2c_platform_probe(struct platform_device *pdev)
308{
309 struct i2c_platform_data *priv;
310 struct resource *r;
311 int ret;
312
313 pr_debug("i2c_platform_probe\n");
314 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
315 if (!r) {
316 ret = -ENODEV;
317 goto out;
318 }
319
320 priv = kzalloc(sizeof(struct i2c_platform_data), GFP_KERNEL);
321 if (!priv) {
322 ret = -ENOMEM;
323 goto out;
324 }
325
326
327#if 0
328 priv->base = bus_request_region(r->start, resource_size(r),
329 pdev->name);
330#else
331 priv->base = r->start;
332#endif
333 if (!priv->base) {
334 ret = -EBUSY;
335 goto out_mem;
336 }
337
338 priv->xfer_timeout = 200;
339 priv->ack_timeout = 200;
340 priv->ctl_timeout = 200;
341
342 priv->adap.nr = pdev->id;
343 priv->adap.algo = &platform_algo;
344 priv->adap.algo_data = priv;
345 priv->adap.dev.parent = &pdev->dev;
346 strlcpy(priv->adap.name, "PIC32 I2C", sizeof(priv->adap.name));
347
348 i2c_platform_setup(priv);
349
350 ret = i2c_add_numbered_adapter(&priv->adap);
351 if (ret == 0) {
352 platform_set_drvdata(pdev, priv);
353 return 0;
354 }
355
356 i2c_platform_disable(priv);
357
358out_mem:
359 kfree(priv);
360out:
361 return ret;
362}
363
364static int i2c_platform_remove(struct platform_device *pdev)
365{
366 struct i2c_platform_data *priv = platform_get_drvdata(pdev);
367
368 pr_debug("i2c_platform_remove\n");
369 platform_set_drvdata(pdev, NULL);
370 i2c_del_adapter(&priv->adap);
371 i2c_platform_disable(priv);
372 kfree(priv);
373 return 0;
374}
375
376#ifdef CONFIG_PM
377static int
378i2c_platform_suspend(struct platform_device *pdev, pm_message_t state)
379{
380 struct i2c_platform_data *priv = platform_get_drvdata(pdev);
381
382 dev_dbg(&pdev->dev, "i2c_platform_disable\n");
383 i2c_platform_disable(priv);
384
385 return 0;
386}
387
388static int
389i2c_platform_resume(struct platform_device *pdev)
390{
391 struct i2c_platform_data *priv = platform_get_drvdata(pdev);
392
393 dev_dbg(&pdev->dev, "i2c_platform_setup\n");
394 i2c_platform_setup(priv);
395
396 return 0;
397}
398#else
399#define i2c_platform_suspend NULL
400#define i2c_platform_resume NULL
401#endif
402
403static struct platform_driver i2c_platform_driver = {
404 .driver = {
405 .name = "i2c_pic32",
406 .owner = THIS_MODULE,
407 },
408 .probe = i2c_platform_probe,
409 .remove = i2c_platform_remove,
410 .suspend = i2c_platform_suspend,
411 .resume = i2c_platform_resume,
412};
413
414static int __init
415i2c_platform_init(void)
416{
417 pr_debug("i2c_platform_init\n");
418 return platform_driver_register(&i2c_platform_driver);
419}
420
421static void __exit
422i2c_platform_exit(void)
423{
424 pr_debug("i2c_platform_exit\n");
425 platform_driver_unregister(&i2c_platform_driver);
426}
427
428MODULE_AUTHOR("Chris Dearman, MIPS Technologies INC.");
429MODULE_DESCRIPTION("PIC32 I2C driver");
430MODULE_LICENSE("GPL");
431
432module_init(i2c_platform_init);
433module_exit(i2c_platform_exit);
434
