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b486ddbc OS |
1 | /* |
2 | * drivers/i2c/busses/i2c-s6000.c | |
3 | * | |
4 | * Description: Driver for S6000 Family I2C Interface | |
5 | * Copyright (c) 2008 emlix GmbH | |
85338488 | 6 | * Author: Oskar Schirmer <oskar@scara.com> |
b486ddbc OS |
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> | |
21782180 | 39 | #include <linux/io.h> |
b486ddbc | 40 | |
b486ddbc OS |
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 | ||
0b255e92 | 251 | static u16 nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns) |
b486ddbc OS |
252 | { |
253 | u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000; | |
254 | if (dividend > 0xffff) | |
255 | return 0xffff; | |
256 | return dividend; | |
257 | } | |
258 | ||
0b255e92 | 259 | static int s6i2c_probe(struct platform_device *dev) |
b486ddbc OS |
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) { | |
25985edc | 321 | dev_err(&p_adap->dev, "s6i2c: can't get IRQ %d\n", iface->irq); |
b486ddbc OS |
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); | |
488bf314 | 344 | rc = i2c_add_numbered_adapter(p_adap); |
b486ddbc OS |
345 | if (rc) |
346 | goto err_irq_free; | |
347 | return 0; | |
348 | ||
349 | err_irq_free: | |
350 | free_irq(iface->irq, iface); | |
351 | err_clk_dis: | |
352 | clk_disable(iface->clk); | |
353 | err_clk_put: | |
354 | clk_put(iface->clk); | |
355 | err_map: | |
356 | iounmap(iface->reg); | |
357 | err_reg: | |
358 | release_mem_region(iface->res->start, | |
359 | resource_size(iface->res)); | |
360 | err_out: | |
361 | return rc; | |
362 | } | |
363 | ||
0b255e92 | 364 | static int s6i2c_remove(struct platform_device *pdev) |
b486ddbc OS |
365 | { |
366 | struct s6i2c_if *iface = platform_get_drvdata(pdev); | |
367 | i2c_wr16(iface, S6_I2C_ENABLE, 0); | |
b486ddbc OS |
368 | i2c_del_adapter(&iface->adap); |
369 | free_irq(iface->irq, iface); | |
370 | clk_disable(iface->clk); | |
371 | clk_put(iface->clk); | |
372 | iounmap(iface->reg); | |
373 | release_mem_region(iface->res->start, | |
374 | resource_size(iface->res)); | |
375 | return 0; | |
376 | } | |
377 | ||
378 | static struct platform_driver s6i2c_driver = { | |
379 | .probe = s6i2c_probe, | |
0b255e92 | 380 | .remove = s6i2c_remove, |
b486ddbc OS |
381 | .driver = { |
382 | .name = DRV_NAME, | |
383 | .owner = THIS_MODULE, | |
384 | }, | |
385 | }; | |
386 | ||
387 | static int __init s6i2c_init(void) | |
388 | { | |
389 | pr_info("I2C: S6000 I2C driver\n"); | |
390 | return platform_driver_register(&s6i2c_driver); | |
391 | } | |
392 | ||
393 | static void __exit s6i2c_exit(void) | |
394 | { | |
395 | platform_driver_unregister(&s6i2c_driver); | |
396 | } | |
397 | ||
398 | MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C"); | |
399 | MODULE_LICENSE("GPL"); | |
400 | MODULE_ALIAS("platform:" DRV_NAME); | |
401 | ||
402 | subsys_initcall(s6i2c_init); | |
403 | module_exit(s6i2c_exit); |