Merge branch 'linus' into x86/memtest
[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 };
33
34 /* registers */
35 #define OCI2C_PRELOW            0
36 #define OCI2C_PREHIGH           1
37 #define OCI2C_CONTROL           2
38 #define OCI2C_DATA              3
39 #define OCI2C_CMD               4 /* write only */
40 #define OCI2C_STATUS            4 /* read only, same address as OCI2C_CMD */
41
42 #define OCI2C_CTRL_IEN          0x40
43 #define OCI2C_CTRL_EN           0x80
44
45 #define OCI2C_CMD_START         0x91
46 #define OCI2C_CMD_STOP          0x41
47 #define OCI2C_CMD_READ          0x21
48 #define OCI2C_CMD_WRITE         0x11
49 #define OCI2C_CMD_READ_ACK      0x21
50 #define OCI2C_CMD_READ_NACK     0x29
51 #define OCI2C_CMD_IACK          0x01
52
53 #define OCI2C_STAT_IF           0x01
54 #define OCI2C_STAT_TIP          0x02
55 #define OCI2C_STAT_ARBLOST      0x20
56 #define OCI2C_STAT_BUSY         0x40
57 #define OCI2C_STAT_NACK         0x80
58
59 #define STATE_DONE              0
60 #define STATE_START             1
61 #define STATE_WRITE             2
62 #define STATE_READ              3
63 #define STATE_ERROR             4
64
65 static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
66 {
67         iowrite8(value, i2c->base + reg * i2c->regstep);
68 }
69
70 static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
71 {
72         return ioread8(i2c->base + reg * i2c->regstep);
73 }
74
75 static void ocores_process(struct ocores_i2c *i2c)
76 {
77         struct i2c_msg *msg = i2c->msg;
78         u8 stat = oc_getreg(i2c, OCI2C_STATUS);
79
80         if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
81                 /* stop has been sent */
82                 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
83                 wake_up(&i2c->wait);
84                 return;
85         }
86
87         /* error? */
88         if (stat & OCI2C_STAT_ARBLOST) {
89                 i2c->state = STATE_ERROR;
90                 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
91                 return;
92         }
93
94         if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
95                 i2c->state =
96                         (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
97
98                 if (stat & OCI2C_STAT_NACK) {
99                         i2c->state = STATE_ERROR;
100                         oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
101                         return;
102                 }
103         } else
104                 msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
105
106         /* end of msg? */
107         if (i2c->pos == msg->len) {
108                 i2c->nmsgs--;
109                 i2c->msg++;
110                 i2c->pos = 0;
111                 msg = i2c->msg;
112
113                 if (i2c->nmsgs) {       /* end? */
114                         /* send start? */
115                         if (!(msg->flags & I2C_M_NOSTART)) {
116                                 u8 addr = (msg->addr << 1);
117
118                                 if (msg->flags & I2C_M_RD)
119                                         addr |= 1;
120
121                                 i2c->state = STATE_START;
122
123                                 oc_setreg(i2c, OCI2C_DATA, addr);
124                                 oc_setreg(i2c, OCI2C_CMD,  OCI2C_CMD_START);
125                                 return;
126                         } else
127                                 i2c->state = (msg->flags & I2C_M_RD)
128                                         ? STATE_READ : STATE_WRITE;
129                 } else {
130                         i2c->state = STATE_DONE;
131                         oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
132                         return;
133                 }
134         }
135
136         if (i2c->state == STATE_READ) {
137                 oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
138                           OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
139         } else {
140                 oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
141                 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
142         }
143 }
144
145 static irqreturn_t ocores_isr(int irq, void *dev_id)
146 {
147         struct ocores_i2c *i2c = dev_id;
148
149         ocores_process(i2c);
150
151         return IRQ_HANDLED;
152 }
153
154 static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
155 {
156         struct ocores_i2c *i2c = i2c_get_adapdata(adap);
157
158         i2c->msg = msgs;
159         i2c->pos = 0;
160         i2c->nmsgs = num;
161         i2c->state = STATE_START;
162
163         oc_setreg(i2c, OCI2C_DATA,
164                         (i2c->msg->addr << 1) |
165                         ((i2c->msg->flags & I2C_M_RD) ? 1:0));
166
167         oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
168
169         if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
170                                (i2c->state == STATE_DONE), HZ))
171                 return (i2c->state == STATE_DONE) ? num : -EIO;
172         else
173                 return -ETIMEDOUT;
174 }
175
176 static void ocores_init(struct ocores_i2c *i2c,
177                         struct ocores_i2c_platform_data *pdata)
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 = (pdata->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,
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         ocores_init(i2c, pdata);
252
253         init_waitqueue_head(&i2c->wait);
254         ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c);
255         if (ret) {
256                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
257                 goto request_irq_failed;
258         }
259
260         /* hook up driver to tree */
261         platform_set_drvdata(pdev, i2c);
262         i2c->adap = ocores_adapter;
263         i2c_set_adapdata(&i2c->adap, i2c);
264         i2c->adap.dev.parent = &pdev->dev;
265
266         /* add i2c adapter to i2c tree */
267         ret = i2c_add_adapter(&i2c->adap);
268         if (ret) {
269                 dev_err(&pdev->dev, "Failed to add adapter\n");
270                 goto add_adapter_failed;
271         }
272
273         return 0;
274
275 add_adapter_failed:
276         free_irq(res2->start, i2c);
277 request_irq_failed:
278         iounmap(i2c->base);
279 map_failed:
280         release_mem_region(res->start, res->end - res->start + 1);
281 request_mem_failed:
282         kfree(i2c);
283
284         return ret;
285 }
286
287 static int __devexit ocores_i2c_remove(struct platform_device* pdev)
288 {
289         struct ocores_i2c *i2c = platform_get_drvdata(pdev);
290         struct resource *res;
291
292         /* disable i2c logic */
293         oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
294                   & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
295
296         /* remove adapter & data */
297         i2c_del_adapter(&i2c->adap);
298         platform_set_drvdata(pdev, NULL);
299
300         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
301         if (res)
302                 free_irq(res->start, i2c);
303
304         iounmap(i2c->base);
305
306         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
307         if (res)
308                 release_mem_region(res->start, res->end - res->start + 1);
309
310         kfree(i2c);
311
312         return 0;
313 }
314
315 /* work with hotplug and coldplug */
316 MODULE_ALIAS("platform:ocores-i2c");
317
318 static struct platform_driver ocores_i2c_driver = {
319         .probe  = ocores_i2c_probe,
320         .remove = __devexit_p(ocores_i2c_remove),
321         .driver = {
322                 .owner = THIS_MODULE,
323                 .name = "ocores-i2c",
324         },
325 };
326
327 static int __init ocores_i2c_init(void)
328 {
329         return platform_driver_register(&ocores_i2c_driver);
330 }
331
332 static void __exit ocores_i2c_exit(void)
333 {
334         platform_driver_unregister(&ocores_i2c_driver);
335 }
336
337 module_init(ocores_i2c_init);
338 module_exit(ocores_i2c_exit);
339
340 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
341 MODULE_DESCRIPTION("OpenCores I2C bus driver");
342 MODULE_LICENSE("GPL");