i2c: xtensa s6000 i2c driver
[pandora-kernel.git] / drivers / i2c / busses / i2c-s6000.c
1 /*
2  * drivers/i2c/busses/i2c-s6000.c
3  *
4  * Description: Driver for S6000 Family I2C Interface
5  * Copyright (c) 2008 emlix GmbH
6  * Author:      Oskar Schirmer <os@emlix.com>
7  *
8  * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
9  * Copyright (c) 2005-2007 Analog Devices, Inc.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
24  */
25
26 #include <linux/clk.h>
27 #include <linux/err.h>
28 #include <linux/module.h>
29 #include <linux/kernel.h>
30 #include <linux/init.h>
31 #include <linux/delay.h>
32 #include <linux/i2c.h>
33 #include <linux/i2c/s6000.h>
34 #include <linux/timer.h>
35 #include <linux/spinlock.h>
36 #include <linux/completion.h>
37 #include <linux/interrupt.h>
38 #include <linux/platform_device.h>
39
40 #include <asm/io.h>
41 #include "i2c-s6000.h"
42
43 #define DRV_NAME "i2c-s6000"
44
45 #define POLL_TIMEOUT    (2 * HZ)
46
47 struct s6i2c_if {
48         u8 __iomem              *reg; /* memory mapped registers */
49         int                     irq;
50         spinlock_t              lock;
51         struct i2c_msg          *msgs; /* messages currently handled */
52         int                     msgs_num; /* nb of msgs to do */
53         int                     msgs_push; /* nb of msgs read/written */
54         int                     msgs_done; /* nb of msgs finally handled */
55         unsigned                push; /* nb of bytes read/written in msg */
56         unsigned                done; /* nb of bytes finally handled */
57         int                     timeout_count; /* timeout retries left */
58         struct timer_list       timeout_timer;
59         struct i2c_adapter      adap;
60         struct completion       complete;
61         struct clk              *clk;
62         struct resource         *res;
63 };
64
65 static inline u16 i2c_rd16(struct s6i2c_if *iface, unsigned n)
66 {
67         return readw(iface->reg + (n));
68 }
69
70 static inline void i2c_wr16(struct s6i2c_if *iface, unsigned n, u16 v)
71 {
72         writew(v, iface->reg + (n));
73 }
74
75 static inline u32 i2c_rd32(struct s6i2c_if *iface, unsigned n)
76 {
77         return readl(iface->reg + (n));
78 }
79
80 static inline void i2c_wr32(struct s6i2c_if *iface, unsigned n, u32 v)
81 {
82         writel(v, iface->reg + (n));
83 }
84
85 static struct s6i2c_if s6i2c_if;
86
87 static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
88 {
89         if (i2c_rd16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
90                 i2c_rd16(iface, S6_I2C_CLRTXABRT);
91                 i2c_wr16(iface, S6_I2C_INTRMASK, 0);
92                 complete(&iface->complete);
93                 return;
94         }
95         if (iface->msgs_done >= iface->msgs_num) {
96                 dev_err(&iface->adap.dev, "s6i2c: spurious I2C irq: %04x\n",
97                         i2c_rd16(iface, S6_I2C_INTRSTAT));
98                 i2c_wr16(iface, S6_I2C_INTRMASK, 0);
99                 return;
100         }
101         while ((iface->msgs_push < iface->msgs_num)
102             && (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
103                 struct i2c_msg *m = &iface->msgs[iface->msgs_push];
104                 if (!(m->flags & I2C_M_RD))
105                         i2c_wr16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
106                 else
107                         i2c_wr16(iface, S6_I2C_DATACMD,
108                                  1 << S6_I2C_DATACMD_READ);
109                 if (++iface->push >= m->len) {
110                         iface->push = 0;
111                         iface->msgs_push += 1;
112                 }
113         }
114         do {
115                 struct i2c_msg *m = &iface->msgs[iface->msgs_done];
116                 if (!(m->flags & I2C_M_RD)) {
117                         if (iface->msgs_done < iface->msgs_push)
118                                 iface->msgs_done += 1;
119                         else
120                                 break;
121                 } else if (i2c_rd16(iface, S6_I2C_STATUS)
122                                 & (1 << S6_I2C_STATUS_RFNE)) {
123                         m->buf[iface->done] = i2c_rd16(iface, S6_I2C_DATACMD);
124                         if (++iface->done >= m->len) {
125                                 iface->done = 0;
126                                 iface->msgs_done += 1;
127                         }
128                 } else{
129                         break;
130                 }
131         } while (iface->msgs_done < iface->msgs_num);
132         if (iface->msgs_done >= iface->msgs_num) {
133                 i2c_wr16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
134                 complete(&iface->complete);
135         } else if (iface->msgs_push >= iface->msgs_num) {
136                 i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
137                                                  (1 << S6_I2C_INTR_RXFULL));
138         } else {
139                 i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
140                                                  (1 << S6_I2C_INTR_TXEMPTY) |
141                                                  (1 << S6_I2C_INTR_RXFULL));
142         }
143 }
144
145 static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
146 {
147         struct s6i2c_if *iface = dev_id;
148         if (!(i2c_rd16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
149                                               | (1 << S6_I2C_INTR_RXOVER)
150                                               | (1 << S6_I2C_INTR_RXFULL)
151                                               | (1 << S6_I2C_INTR_TXOVER)
152                                               | (1 << S6_I2C_INTR_TXEMPTY)
153                                               | (1 << S6_I2C_INTR_RDREQ)
154                                               | (1 << S6_I2C_INTR_TXABRT)
155                                               | (1 << S6_I2C_INTR_RXDONE)
156                                               | (1 << S6_I2C_INTR_ACTIVITY)
157                                               | (1 << S6_I2C_INTR_STOPDET)
158                                               | (1 << S6_I2C_INTR_STARTDET)
159                                               | (1 << S6_I2C_INTR_GENCALL))))
160                 return IRQ_NONE;
161
162         spin_lock(&iface->lock);
163         del_timer(&iface->timeout_timer);
164         s6i2c_handle_interrupt(iface);
165         spin_unlock(&iface->lock);
166         return IRQ_HANDLED;
167 }
168
169 static void s6i2c_timeout(unsigned long data)
170 {
171         struct s6i2c_if *iface = (struct s6i2c_if *)data;
172         unsigned long flags;
173
174         spin_lock_irqsave(&iface->lock, flags);
175         s6i2c_handle_interrupt(iface);
176         if (--iface->timeout_count > 0) {
177                 iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
178                 add_timer(&iface->timeout_timer);
179         } else {
180                 complete(&iface->complete);
181                 i2c_wr16(iface, S6_I2C_INTRMASK, 0);
182         }
183         spin_unlock_irqrestore(&iface->lock, flags);
184 }
185
186 static int s6i2c_master_xfer(struct i2c_adapter *adap,
187                                 struct i2c_msg *msgs, int num)
188 {
189         struct s6i2c_if *iface = adap->algo_data;
190         int i;
191         if (num == 0)
192                 return 0;
193         if (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
194                 yield();
195         i2c_wr16(iface, S6_I2C_INTRMASK, 0);
196         i2c_rd16(iface, S6_I2C_CLRINTR);
197         for (i = 0; i < num; i++) {
198                 if (msgs[i].flags & I2C_M_TEN) {
199                         dev_err(&adap->dev,
200                                 "s6i2c: 10 bits addr not supported\n");
201                         return -EINVAL;
202                 }
203                 if (msgs[i].len == 0) {
204                         dev_err(&adap->dev,
205                                 "s6i2c: zero length message not supported\n");
206                         return -EINVAL;
207                 }
208                 if (msgs[i].addr != msgs[0].addr) {
209                         dev_err(&adap->dev,
210                                 "s6i2c: multiple xfer cannot change target\n");
211                         return -EINVAL;
212                 }
213         }
214
215         iface->msgs = msgs;
216         iface->msgs_num = num;
217         iface->msgs_push = 0;
218         iface->msgs_done = 0;
219         iface->push = 0;
220         iface->done = 0;
221         iface->timeout_count = 10;
222         i2c_wr16(iface, S6_I2C_TAR, msgs[0].addr);
223         i2c_wr16(iface, S6_I2C_ENABLE, 1);
224         i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
225                                          (1 << S6_I2C_INTR_TXABRT));
226
227         iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
228         add_timer(&iface->timeout_timer);
229         wait_for_completion(&iface->complete);
230         del_timer_sync(&iface->timeout_timer);
231         while (i2c_rd32(iface, S6_I2C_TXFLR) > 0)
232                 schedule();
233         while (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
234                 schedule();
235
236         i2c_wr16(iface, S6_I2C_INTRMASK, 0);
237         i2c_wr16(iface, S6_I2C_ENABLE, 0);
238         return iface->msgs_done;
239 }
240
241 static u32 s6i2c_functionality(struct i2c_adapter *adap)
242 {
243         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
244 }
245
246 static struct i2c_algorithm s6i2c_algorithm = {
247         .master_xfer   = s6i2c_master_xfer,
248         .functionality = s6i2c_functionality,
249 };
250
251 static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
252 {
253         u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000;
254         if (dividend > 0xffff)
255                 return 0xffff;
256         return dividend;
257 }
258
259 static int __devinit s6i2c_probe(struct platform_device *dev)
260 {
261         struct s6i2c_if *iface = &s6i2c_if;
262         struct i2c_adapter *p_adap;
263         const char *clock;
264         int bus_num, rc;
265         spin_lock_init(&iface->lock);
266         init_completion(&iface->complete);
267         iface->irq = platform_get_irq(dev, 0);
268         if (iface->irq < 0) {
269                 rc = iface->irq;
270                 goto err_out;
271         }
272         iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
273         if (!iface->res) {
274                 rc = -ENXIO;
275                 goto err_out;
276         }
277         iface->res = request_mem_region(iface->res->start,
278                                         resource_size(iface->res),
279                                         dev->dev.bus_id);
280         if (!iface->res) {
281                 rc = -EBUSY;
282                 goto err_out;
283         }
284         iface->reg = ioremap_nocache(iface->res->start,
285                                      resource_size(iface->res));
286         if (!iface->reg) {
287                 rc = -ENOMEM;
288                 goto err_reg;
289         }
290
291         clock = 0;
292         bus_num = -1;
293         if (dev->dev.platform_data) {
294                 struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
295                 bus_num = pdata->bus_num;
296                 clock = pdata->clock;
297         }
298         iface->clk = clk_get(&dev->dev, clock);
299         if (IS_ERR(iface->clk)) {
300                 rc = PTR_ERR(iface->clk);
301                 goto err_map;
302         }
303         rc = clk_enable(iface->clk);
304         if (rc < 0)
305                 goto err_clk_put;
306         init_timer(&iface->timeout_timer);
307         iface->timeout_timer.function = s6i2c_timeout;
308         iface->timeout_timer.data = (unsigned long)iface;
309
310         p_adap = &iface->adap;
311         strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
312         p_adap->algo = &s6i2c_algorithm;
313         p_adap->algo_data = iface;
314         p_adap->nr = bus_num;
315         p_adap->class = 0;
316         p_adap->dev.parent = &dev->dev;
317         i2c_wr16(iface, S6_I2C_INTRMASK, 0);
318         rc = request_irq(iface->irq, s6i2c_interrupt_entry,
319                          IRQF_SHARED, dev->name, iface);
320         if (rc) {
321                 dev_err(&p_adap->dev, "s6i2c: cant get IRQ %d\n", iface->irq);
322                 goto err_clk_dis;
323         }
324
325         i2c_wr16(iface, S6_I2C_ENABLE, 0);
326         udelay(1);
327         i2c_wr32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
328         i2c_wr16(iface, S6_I2C_CLRTXABRT, 1);
329         i2c_wr16(iface, S6_I2C_CON,
330                         (1 << S6_I2C_CON_MASTER) |
331                         (S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
332                         (0 << S6_I2C_CON_10BITSLAVE) |
333                         (0 << S6_I2C_CON_10BITMASTER) |
334                         (1 << S6_I2C_CON_RESTARTENA) |
335                         (1 << S6_I2C_CON_SLAVEDISABLE));
336         i2c_wr16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
337         i2c_wr16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
338         i2c_wr16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
339         i2c_wr16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
340         i2c_wr16(iface, S6_I2C_RXTL, 0);
341         i2c_wr16(iface, S6_I2C_TXTL, 0);
342
343         platform_set_drvdata(dev, iface);
344         if (bus_num < 0)
345                 rc = i2c_add_adapter(p_adap);
346         else
347                 rc = i2c_add_numbered_adapter(p_adap);
348         if (rc)
349                 goto err_irq_free;
350         return 0;
351
352 err_irq_free:
353         free_irq(iface->irq, iface);
354 err_clk_dis:
355         clk_disable(iface->clk);
356 err_clk_put:
357         clk_put(iface->clk);
358 err_map:
359         iounmap(iface->reg);
360 err_reg:
361         release_mem_region(iface->res->start,
362                            resource_size(iface->res));
363 err_out:
364         return rc;
365 }
366
367 static int __devexit s6i2c_remove(struct platform_device *pdev)
368 {
369         struct s6i2c_if *iface = platform_get_drvdata(pdev);
370         i2c_wr16(iface, S6_I2C_ENABLE, 0);
371         platform_set_drvdata(pdev, NULL);
372         i2c_del_adapter(&iface->adap);
373         free_irq(iface->irq, iface);
374         clk_disable(iface->clk);
375         clk_put(iface->clk);
376         iounmap(iface->reg);
377         release_mem_region(iface->res->start,
378                            resource_size(iface->res));
379         return 0;
380 }
381
382 static struct platform_driver s6i2c_driver = {
383         .probe          = s6i2c_probe,
384         .remove         = __devexit_p(s6i2c_remove),
385         .driver         = {
386                 .name   = DRV_NAME,
387                 .owner  = THIS_MODULE,
388         },
389 };
390
391 static int __init s6i2c_init(void)
392 {
393         pr_info("I2C: S6000 I2C driver\n");
394         return platform_driver_register(&s6i2c_driver);
395 }
396
397 static void __exit s6i2c_exit(void)
398 {
399         platform_driver_unregister(&s6i2c_driver);
400 }
401
402 MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
403 MODULE_LICENSE("GPL");
404 MODULE_ALIAS("platform:" DRV_NAME);
405
406 subsys_initcall(s6i2c_init);
407 module_exit(s6i2c_exit);