Merge branch 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze
[linux-2.6] / drivers / i2c / busses / i2c-ocores.c
1 /*
2  * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
3  * (http://www.opencores.org/projects.cgi/web/i2c/overview).
4  *
5  * Peter Korsgaard <jacmet@sunsite.dk>
6  *
7  * This file is licensed under the terms of the GNU General Public License
8  * version 2.  This program is licensed "as is" without any warranty of any
9  * kind, whether express or implied.
10  */
11
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/errno.h>
16 #include <linux/platform_device.h>
17 #include <linux/i2c.h>
18 #include <linux/interrupt.h>
19 #include <linux/wait.h>
20 #include <linux/i2c-ocores.h>
21 #include <asm/io.h>
22
23 struct ocores_i2c {
24         void __iomem *base;
25         int regstep;
26         wait_queue_head_t wait;
27         struct i2c_adapter adap;
28         struct i2c_msg *msg;
29         int pos;
30         int nmsgs;
31         int state; /* see STATE_ */
32         int clock_khz;
33 };
34
35 /* registers */
36 #define OCI2C_PRELOW            0
37 #define OCI2C_PREHIGH           1
38 #define OCI2C_CONTROL           2
39 #define OCI2C_DATA              3
40 #define OCI2C_CMD               4 /* write only */
41 #define OCI2C_STATUS            4 /* read only, same address as OCI2C_CMD */
42
43 #define OCI2C_CTRL_IEN          0x40
44 #define OCI2C_CTRL_EN           0x80
45
46 #define OCI2C_CMD_START         0x91
47 #define OCI2C_CMD_STOP          0x41
48 #define OCI2C_CMD_READ          0x21
49 #define OCI2C_CMD_WRITE         0x11
50 #define OCI2C_CMD_READ_ACK      0x21
51 #define OCI2C_CMD_READ_NACK     0x29
52 #define OCI2C_CMD_IACK          0x01
53
54 #define OCI2C_STAT_IF           0x01
55 #define OCI2C_STAT_TIP          0x02
56 #define OCI2C_STAT_ARBLOST      0x20
57 #define OCI2C_STAT_BUSY         0x40
58 #define OCI2C_STAT_NACK         0x80
59
60 #define STATE_DONE              0
61 #define STATE_START             1
62 #define STATE_WRITE             2
63 #define STATE_READ              3
64 #define STATE_ERROR             4
65
66 static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
67 {
68         iowrite8(value, i2c->base + reg * i2c->regstep);
69 }
70
71 static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
72 {
73         return ioread8(i2c->base + reg * i2c->regstep);
74 }
75
76 static void ocores_process(struct ocores_i2c *i2c)
77 {
78         struct i2c_msg *msg = i2c->msg;
79         u8 stat = oc_getreg(i2c, OCI2C_STATUS);
80
81         if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
82                 /* stop has been sent */
83                 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
84                 wake_up(&i2c->wait);
85                 return;
86         }
87
88         /* error? */
89         if (stat & OCI2C_STAT_ARBLOST) {
90                 i2c->state = STATE_ERROR;
91                 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
92                 return;
93         }
94
95         if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
96                 i2c->state =
97                         (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
98
99                 if (stat & OCI2C_STAT_NACK) {
100                         i2c->state = STATE_ERROR;
101                         oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
102                         return;
103                 }
104         } else
105                 msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
106
107         /* end of msg? */
108         if (i2c->pos == msg->len) {
109                 i2c->nmsgs--;
110                 i2c->msg++;
111                 i2c->pos = 0;
112                 msg = i2c->msg;
113
114                 if (i2c->nmsgs) {       /* end? */
115                         /* send start? */
116                         if (!(msg->flags & I2C_M_NOSTART)) {
117                                 u8 addr = (msg->addr << 1);
118
119                                 if (msg->flags & I2C_M_RD)
120                                         addr |= 1;
121
122                                 i2c->state = STATE_START;
123
124                                 oc_setreg(i2c, OCI2C_DATA, addr);
125                                 oc_setreg(i2c, OCI2C_CMD,  OCI2C_CMD_START);
126                                 return;
127                         } else
128                                 i2c->state = (msg->flags & I2C_M_RD)
129                                         ? STATE_READ : STATE_WRITE;
130                 } else {
131                         i2c->state = STATE_DONE;
132                         oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
133                         return;
134                 }
135         }
136
137         if (i2c->state == STATE_READ) {
138                 oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
139                           OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
140         } else {
141                 oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
142                 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
143         }
144 }
145
146 static irqreturn_t ocores_isr(int irq, void *dev_id)
147 {
148         struct ocores_i2c *i2c = dev_id;
149
150         ocores_process(i2c);
151
152         return IRQ_HANDLED;
153 }
154
155 static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
156 {
157         struct ocores_i2c *i2c = i2c_get_adapdata(adap);
158
159         i2c->msg = msgs;
160         i2c->pos = 0;
161         i2c->nmsgs = num;
162         i2c->state = STATE_START;
163
164         oc_setreg(i2c, OCI2C_DATA,
165                         (i2c->msg->addr << 1) |
166                         ((i2c->msg->flags & I2C_M_RD) ? 1:0));
167
168         oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
169
170         if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
171                                (i2c->state == STATE_DONE), HZ))
172                 return (i2c->state == STATE_DONE) ? num : -EIO;
173         else
174                 return -ETIMEDOUT;
175 }
176
177 static void ocores_init(struct ocores_i2c *i2c)
178 {
179         int prescale;
180         u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
181
182         /* make sure the device is disabled */
183         oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
184
185         prescale = (i2c->clock_khz / (5*100)) - 1;
186         oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
187         oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);
188
189         /* Init the device */
190         oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
191         oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);
192 }
193
194
195 static u32 ocores_func(struct i2c_adapter *adap)
196 {
197         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
198 }
199
200 static const struct i2c_algorithm ocores_algorithm = {
201         .master_xfer    = ocores_xfer,
202         .functionality  = ocores_func,
203 };
204
205 static struct i2c_adapter ocores_adapter = {
206         .owner          = THIS_MODULE,
207         .name           = "i2c-ocores",
208         .class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
209         .algo           = &ocores_algorithm,
210 };
211
212
213 static int __devinit ocores_i2c_probe(struct platform_device *pdev)
214 {
215         struct ocores_i2c *i2c;
216         struct ocores_i2c_platform_data *pdata;
217         struct resource *res, *res2;
218         int ret;
219
220         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
221         if (!res)
222                 return -ENODEV;
223
224         res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
225         if (!res2)
226                 return -ENODEV;
227
228         pdata = (struct ocores_i2c_platform_data*) pdev->dev.platform_data;
229         if (!pdata)
230                 return -ENODEV;
231
232         i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
233         if (!i2c)
234                 return -ENOMEM;
235
236         if (!request_mem_region(res->start, res->end - res->start + 1,
237                                 pdev->name)) {
238                 dev_err(&pdev->dev, "Memory region busy\n");
239                 ret = -EBUSY;
240                 goto request_mem_failed;
241         }
242
243         i2c->base = ioremap(res->start, res->end - res->start + 1);
244         if (!i2c->base) {
245                 dev_err(&pdev->dev, "Unable to map registers\n");
246                 ret = -EIO;
247                 goto map_failed;
248         }
249
250         i2c->regstep = pdata->regstep;
251         i2c->clock_khz = pdata->clock_khz;
252         ocores_init(i2c);
253
254         init_waitqueue_head(&i2c->wait);
255         ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c);
256         if (ret) {
257                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
258                 goto request_irq_failed;
259         }
260
261         /* hook up driver to tree */
262         platform_set_drvdata(pdev, i2c);
263         i2c->adap = ocores_adapter;
264         i2c_set_adapdata(&i2c->adap, i2c);
265         i2c->adap.dev.parent = &pdev->dev;
266
267         /* add i2c adapter to i2c tree */
268         ret = i2c_add_adapter(&i2c->adap);
269         if (ret) {
270                 dev_err(&pdev->dev, "Failed to add adapter\n");
271                 goto add_adapter_failed;
272         }
273
274         return 0;
275
276 add_adapter_failed:
277         free_irq(res2->start, i2c);
278 request_irq_failed:
279         iounmap(i2c->base);
280 map_failed:
281         release_mem_region(res->start, res->end - res->start + 1);
282 request_mem_failed:
283         kfree(i2c);
284
285         return ret;
286 }
287
288 static int __devexit ocores_i2c_remove(struct platform_device* pdev)
289 {
290         struct ocores_i2c *i2c = platform_get_drvdata(pdev);
291         struct resource *res;
292
293         /* disable i2c logic */
294         oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
295                   & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
296
297         /* remove adapter & data */
298         i2c_del_adapter(&i2c->adap);
299         platform_set_drvdata(pdev, NULL);
300
301         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
302         if (res)
303                 free_irq(res->start, i2c);
304
305         iounmap(i2c->base);
306
307         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
308         if (res)
309                 release_mem_region(res->start, res->end - res->start + 1);
310
311         kfree(i2c);
312
313         return 0;
314 }
315
316 #ifdef CONFIG_PM
317 static int ocores_i2c_suspend(struct platform_device *pdev, pm_message_t state)
318 {
319         struct ocores_i2c *i2c = platform_get_drvdata(pdev);
320         u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
321
322         /* make sure the device is disabled */
323         oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
324
325         return 0;
326 }
327
328 static int ocores_i2c_resume(struct platform_device *pdev)
329 {
330         struct ocores_i2c *i2c = platform_get_drvdata(pdev);
331
332         ocores_init(i2c);
333
334         return 0;
335 }
336 #else
337 #define ocores_i2c_suspend      NULL
338 #define ocores_i2c_resume       NULL
339 #endif
340
341 /* work with hotplug and coldplug */
342 MODULE_ALIAS("platform:ocores-i2c");
343
344 static struct platform_driver ocores_i2c_driver = {
345         .probe   = ocores_i2c_probe,
346         .remove  = __devexit_p(ocores_i2c_remove),
347         .suspend = ocores_i2c_suspend,
348         .resume  = ocores_i2c_resume,
349         .driver  = {
350                 .owner = THIS_MODULE,
351                 .name = "ocores-i2c",
352         },
353 };
354
355 static int __init ocores_i2c_init(void)
356 {
357         return platform_driver_register(&ocores_i2c_driver);
358 }
359
360 static void __exit ocores_i2c_exit(void)
361 {
362         platform_driver_unregister(&ocores_i2c_driver);
363 }
364
365 module_init(ocores_i2c_init);
366 module_exit(ocores_i2c_exit);
367
368 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
369 MODULE_DESCRIPTION("OpenCores I2C bus driver");
370 MODULE_LICENSE("GPL");