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[mirror_ubuntu-artful-kernel.git] / drivers / i2c / busses / i2c-ocores.c
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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
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12#include <linux/kernel.h>
13#include <linux/module.h>
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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>
5a0e3ad6 21#include <linux/slab.h>
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22#include <asm/io.h>
23
24struct ocores_i2c {
25 void __iomem *base;
26 int regstep;
27 wait_queue_head_t wait;
28 struct i2c_adapter adap;
29 struct i2c_msg *msg;
30 int pos;
31 int nmsgs;
32 int state; /* see STATE_ */
2373c180 33 int clock_khz;
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34};
35
36/* registers */
37#define OCI2C_PRELOW 0
38#define OCI2C_PREHIGH 1
39#define OCI2C_CONTROL 2
40#define OCI2C_DATA 3
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41#define OCI2C_CMD 4 /* write only */
42#define OCI2C_STATUS 4 /* read only, same address as OCI2C_CMD */
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43
44#define OCI2C_CTRL_IEN 0x40
45#define OCI2C_CTRL_EN 0x80
46
47#define OCI2C_CMD_START 0x91
48#define OCI2C_CMD_STOP 0x41
49#define OCI2C_CMD_READ 0x21
50#define OCI2C_CMD_WRITE 0x11
51#define OCI2C_CMD_READ_ACK 0x21
52#define OCI2C_CMD_READ_NACK 0x29
53#define OCI2C_CMD_IACK 0x01
54
55#define OCI2C_STAT_IF 0x01
56#define OCI2C_STAT_TIP 0x02
57#define OCI2C_STAT_ARBLOST 0x20
58#define OCI2C_STAT_BUSY 0x40
59#define OCI2C_STAT_NACK 0x80
60
61#define STATE_DONE 0
62#define STATE_START 1
63#define STATE_WRITE 2
64#define STATE_READ 3
65#define STATE_ERROR 4
66
67static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
68{
69 iowrite8(value, i2c->base + reg * i2c->regstep);
70}
71
72static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
73{
74 return ioread8(i2c->base + reg * i2c->regstep);
75}
76
77static void ocores_process(struct ocores_i2c *i2c)
78{
79 struct i2c_msg *msg = i2c->msg;
80 u8 stat = oc_getreg(i2c, OCI2C_STATUS);
81
82 if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
83 /* stop has been sent */
84 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
85 wake_up(&i2c->wait);
86 return;
87 }
88
89 /* error? */
90 if (stat & OCI2C_STAT_ARBLOST) {
91 i2c->state = STATE_ERROR;
92 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
93 return;
94 }
95
96 if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
97 i2c->state =
98 (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
99
100 if (stat & OCI2C_STAT_NACK) {
101 i2c->state = STATE_ERROR;
102 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
103 return;
104 }
105 } else
106 msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
107
108 /* end of msg? */
109 if (i2c->pos == msg->len) {
110 i2c->nmsgs--;
111 i2c->msg++;
112 i2c->pos = 0;
113 msg = i2c->msg;
114
115 if (i2c->nmsgs) { /* end? */
116 /* send start? */
117 if (!(msg->flags & I2C_M_NOSTART)) {
118 u8 addr = (msg->addr << 1);
119
120 if (msg->flags & I2C_M_RD)
121 addr |= 1;
122
123 i2c->state = STATE_START;
124
125 oc_setreg(i2c, OCI2C_DATA, addr);
126 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
127 return;
128 } else
129 i2c->state = (msg->flags & I2C_M_RD)
130 ? STATE_READ : STATE_WRITE;
131 } else {
132 i2c->state = STATE_DONE;
133 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
134 return;
135 }
136 }
137
138 if (i2c->state == STATE_READ) {
139 oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
140 OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
141 } else {
142 oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
143 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
144 }
145}
146
7d12e780 147static irqreturn_t ocores_isr(int irq, void *dev_id)
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148{
149 struct ocores_i2c *i2c = dev_id;
150
151 ocores_process(i2c);
152
153 return IRQ_HANDLED;
154}
155
156static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
157{
158 struct ocores_i2c *i2c = i2c_get_adapdata(adap);
159
160 i2c->msg = msgs;
161 i2c->pos = 0;
162 i2c->nmsgs = num;
163 i2c->state = STATE_START;
164
165 oc_setreg(i2c, OCI2C_DATA,
166 (i2c->msg->addr << 1) |
167 ((i2c->msg->flags & I2C_M_RD) ? 1:0));
168
169 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
170
171 if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
172 (i2c->state == STATE_DONE), HZ))
173 return (i2c->state == STATE_DONE) ? num : -EIO;
174 else
175 return -ETIMEDOUT;
176}
177
2373c180 178static void ocores_init(struct ocores_i2c *i2c)
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179{
180 int prescale;
181 u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
182
183 /* make sure the device is disabled */
184 oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
185
2373c180 186 prescale = (i2c->clock_khz / (5*100)) - 1;
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187 oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
188 oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);
189
190 /* Init the device */
191 oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
192 oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);
193}
194
195
196static u32 ocores_func(struct i2c_adapter *adap)
197{
198 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
199}
200
8f9082c5 201static const struct i2c_algorithm ocores_algorithm = {
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202 .master_xfer = ocores_xfer,
203 .functionality = ocores_func,
204};
205
206static struct i2c_adapter ocores_adapter = {
207 .owner = THIS_MODULE,
208 .name = "i2c-ocores",
3401b2ff 209 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
18f98b1e 210 .algo = &ocores_algorithm,
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211};
212
213
214static int __devinit ocores_i2c_probe(struct platform_device *pdev)
215{
216 struct ocores_i2c *i2c;
217 struct ocores_i2c_platform_data *pdata;
218 struct resource *res, *res2;
219 int ret;
dd14be4c 220 int i;
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221
222 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
223 if (!res)
224 return -ENODEV;
225
226 res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
227 if (!res2)
228 return -ENODEV;
229
230 pdata = (struct ocores_i2c_platform_data*) pdev->dev.platform_data;
231 if (!pdata)
232 return -ENODEV;
233
234 i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
235 if (!i2c)
236 return -ENOMEM;
237
c6ffddea 238 if (!request_mem_region(res->start, resource_size(res),
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239 pdev->name)) {
240 dev_err(&pdev->dev, "Memory region busy\n");
241 ret = -EBUSY;
242 goto request_mem_failed;
243 }
244
c6ffddea 245 i2c->base = ioremap(res->start, resource_size(res));
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246 if (!i2c->base) {
247 dev_err(&pdev->dev, "Unable to map registers\n");
248 ret = -EIO;
249 goto map_failed;
250 }
251
252 i2c->regstep = pdata->regstep;
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253 i2c->clock_khz = pdata->clock_khz;
254 ocores_init(i2c);
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255
256 init_waitqueue_head(&i2c->wait);
257 ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c);
258 if (ret) {
259 dev_err(&pdev->dev, "Cannot claim IRQ\n");
260 goto request_irq_failed;
261 }
262
263 /* hook up driver to tree */
264 platform_set_drvdata(pdev, i2c);
265 i2c->adap = ocores_adapter;
266 i2c_set_adapdata(&i2c->adap, i2c);
267 i2c->adap.dev.parent = &pdev->dev;
268
269 /* add i2c adapter to i2c tree */
270 ret = i2c_add_adapter(&i2c->adap);
271 if (ret) {
272 dev_err(&pdev->dev, "Failed to add adapter\n");
273 goto add_adapter_failed;
274 }
275
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276 /* add in known devices to the bus */
277 for (i = 0; i < pdata->num_devices; i++)
278 i2c_new_device(&i2c->adap, pdata->devices + i);
279
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280 return 0;
281
282add_adapter_failed:
283 free_irq(res2->start, i2c);
284request_irq_failed:
285 iounmap(i2c->base);
286map_failed:
c6ffddea 287 release_mem_region(res->start, resource_size(res));
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288request_mem_failed:
289 kfree(i2c);
290
291 return ret;
292}
293
294static int __devexit ocores_i2c_remove(struct platform_device* pdev)
295{
296 struct ocores_i2c *i2c = platform_get_drvdata(pdev);
297 struct resource *res;
298
299 /* disable i2c logic */
300 oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
301 & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
302
303 /* remove adapter & data */
304 i2c_del_adapter(&i2c->adap);
305 platform_set_drvdata(pdev, NULL);
306
307 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
308 if (res)
309 free_irq(res->start, i2c);
310
311 iounmap(i2c->base);
312
313 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
314 if (res)
c6ffddea 315 release_mem_region(res->start, resource_size(res));
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316
317 kfree(i2c);
318
319 return 0;
320}
321
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322#ifdef CONFIG_PM
323static int ocores_i2c_suspend(struct platform_device *pdev, pm_message_t state)
324{
325 struct ocores_i2c *i2c = platform_get_drvdata(pdev);
326 u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
327
328 /* make sure the device is disabled */
329 oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
330
331 return 0;
332}
333
334static int ocores_i2c_resume(struct platform_device *pdev)
335{
336 struct ocores_i2c *i2c = platform_get_drvdata(pdev);
337
338 ocores_init(i2c);
339
340 return 0;
341}
342#else
343#define ocores_i2c_suspend NULL
344#define ocores_i2c_resume NULL
345#endif
346
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347/* work with hotplug and coldplug */
348MODULE_ALIAS("platform:ocores-i2c");
349
18f98b1e 350static struct platform_driver ocores_i2c_driver = {
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351 .probe = ocores_i2c_probe,
352 .remove = __devexit_p(ocores_i2c_remove),
353 .suspend = ocores_i2c_suspend,
354 .resume = ocores_i2c_resume,
355 .driver = {
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356 .owner = THIS_MODULE,
357 .name = "ocores-i2c",
358 },
359};
360
361static int __init ocores_i2c_init(void)
362{
363 return platform_driver_register(&ocores_i2c_driver);
364}
365
366static void __exit ocores_i2c_exit(void)
367{
368 platform_driver_unregister(&ocores_i2c_driver);
369}
370
371module_init(ocores_i2c_init);
372module_exit(ocores_i2c_exit);
373
374MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
375MODULE_DESCRIPTION("OpenCores I2C bus driver");
376MODULE_LICENSE("GPL");