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1 | /* | |
2 | * Wondermedia I2C Master Mode Driver | |
3 | * | |
4 | * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz> | |
5 | * | |
6 | * Derived from GPLv2+ licensed source: | |
7 | * - Copyright (C) 2008 WonderMedia Technologies, Inc. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2, or | |
11 | * (at your option) any later version. as published by the Free Software | |
12 | * Foundation | |
13 | */ | |
14 | ||
15 | #include <linux/clk.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/i2c.h> | |
19 | #include <linux/interrupt.h> | |
20 | #include <linux/io.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/of.h> | |
23 | #include <linux/of_address.h> | |
24 | #include <linux/of_irq.h> | |
25 | #include <linux/platform_device.h> | |
26 | ||
27 | #define REG_CR 0x00 | |
28 | #define REG_TCR 0x02 | |
29 | #define REG_CSR 0x04 | |
30 | #define REG_ISR 0x06 | |
31 | #define REG_IMR 0x08 | |
32 | #define REG_CDR 0x0A | |
33 | #define REG_TR 0x0C | |
34 | #define REG_MCR 0x0E | |
35 | #define REG_SLAVE_CR 0x10 | |
36 | #define REG_SLAVE_SR 0x12 | |
37 | #define REG_SLAVE_ISR 0x14 | |
38 | #define REG_SLAVE_IMR 0x16 | |
39 | #define REG_SLAVE_DR 0x18 | |
40 | #define REG_SLAVE_TR 0x1A | |
41 | ||
42 | /* REG_CR Bit fields */ | |
43 | #define CR_TX_NEXT_ACK 0x0000 | |
44 | #define CR_ENABLE 0x0001 | |
45 | #define CR_TX_NEXT_NO_ACK 0x0002 | |
46 | #define CR_TX_END 0x0004 | |
47 | #define CR_CPU_RDY 0x0008 | |
48 | #define SLAV_MODE_SEL 0x8000 | |
49 | ||
50 | /* REG_TCR Bit fields */ | |
51 | #define TCR_STANDARD_MODE 0x0000 | |
52 | #define TCR_MASTER_WRITE 0x0000 | |
53 | #define TCR_HS_MODE 0x2000 | |
54 | #define TCR_MASTER_READ 0x4000 | |
55 | #define TCR_FAST_MODE 0x8000 | |
56 | #define TCR_SLAVE_ADDR_MASK 0x007F | |
57 | ||
58 | /* REG_ISR Bit fields */ | |
59 | #define ISR_NACK_ADDR 0x0001 | |
60 | #define ISR_BYTE_END 0x0002 | |
61 | #define ISR_SCL_TIMEOUT 0x0004 | |
62 | #define ISR_WRITE_ALL 0x0007 | |
63 | ||
64 | /* REG_IMR Bit fields */ | |
65 | #define IMR_ENABLE_ALL 0x0007 | |
66 | ||
67 | /* REG_CSR Bit fields */ | |
68 | #define CSR_RCV_NOT_ACK 0x0001 | |
69 | #define CSR_RCV_ACK_MASK 0x0001 | |
70 | #define CSR_READY_MASK 0x0002 | |
71 | ||
72 | /* REG_TR */ | |
73 | #define SCL_TIMEOUT(x) (((x) & 0xFF) << 8) | |
74 | #define TR_STD 0x0064 | |
75 | #define TR_HS 0x0019 | |
76 | ||
77 | /* REG_MCR */ | |
78 | #define MCR_APB_96M 7 | |
79 | #define MCR_APB_166M 12 | |
80 | ||
81 | #define I2C_MODE_STANDARD 0 | |
82 | #define I2C_MODE_FAST 1 | |
83 | ||
84 | #define WMT_I2C_TIMEOUT (msecs_to_jiffies(1000)) | |
85 | ||
86 | struct wmt_i2c_dev { | |
87 | struct i2c_adapter adapter; | |
88 | struct completion complete; | |
89 | struct device *dev; | |
90 | void __iomem *base; | |
91 | struct clk *clk; | |
92 | int mode; | |
93 | int irq; | |
94 | u16 cmd_status; | |
95 | }; | |
96 | ||
97 | static int wmt_i2c_wait_bus_not_busy(struct wmt_i2c_dev *i2c_dev) | |
98 | { | |
99 | unsigned long timeout; | |
100 | ||
101 | timeout = jiffies + WMT_I2C_TIMEOUT; | |
102 | while (!(readw(i2c_dev->base + REG_CSR) & CSR_READY_MASK)) { | |
103 | if (time_after(jiffies, timeout)) { | |
104 | dev_warn(i2c_dev->dev, "timeout waiting for bus ready\n"); | |
105 | return -EBUSY; | |
106 | } | |
107 | msleep(20); | |
108 | } | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
113 | static int wmt_check_status(struct wmt_i2c_dev *i2c_dev) | |
114 | { | |
115 | int ret = 0; | |
116 | ||
117 | if (i2c_dev->cmd_status & ISR_NACK_ADDR) | |
118 | ret = -EIO; | |
119 | ||
120 | if (i2c_dev->cmd_status & ISR_SCL_TIMEOUT) | |
121 | ret = -ETIMEDOUT; | |
122 | ||
123 | return ret; | |
124 | } | |
125 | ||
126 | static int wmt_i2c_write(struct i2c_adapter *adap, struct i2c_msg *pmsg, | |
127 | int last) | |
128 | { | |
129 | struct wmt_i2c_dev *i2c_dev = i2c_get_adapdata(adap); | |
130 | u16 val, tcr_val; | |
131 | int ret; | |
132 | unsigned long wait_result; | |
133 | int xfer_len = 0; | |
134 | ||
135 | if (!(pmsg->flags & I2C_M_NOSTART)) { | |
136 | ret = wmt_i2c_wait_bus_not_busy(i2c_dev); | |
137 | if (ret < 0) | |
138 | return ret; | |
139 | } | |
140 | ||
141 | if (pmsg->len == 0) { | |
142 | /* | |
143 | * We still need to run through the while (..) once, so | |
144 | * start at -1 and break out early from the loop | |
145 | */ | |
146 | xfer_len = -1; | |
147 | writew(0, i2c_dev->base + REG_CDR); | |
148 | } else { | |
149 | writew(pmsg->buf[0] & 0xFF, i2c_dev->base + REG_CDR); | |
150 | } | |
151 | ||
152 | if (!(pmsg->flags & I2C_M_NOSTART)) { | |
153 | val = readw(i2c_dev->base + REG_CR); | |
154 | val &= ~CR_TX_END; | |
155 | writew(val, i2c_dev->base + REG_CR); | |
156 | ||
157 | val = readw(i2c_dev->base + REG_CR); | |
158 | val |= CR_CPU_RDY; | |
159 | writew(val, i2c_dev->base + REG_CR); | |
160 | } | |
161 | ||
162 | reinit_completion(&i2c_dev->complete); | |
163 | ||
164 | if (i2c_dev->mode == I2C_MODE_STANDARD) | |
165 | tcr_val = TCR_STANDARD_MODE; | |
166 | else | |
167 | tcr_val = TCR_FAST_MODE; | |
168 | ||
169 | tcr_val |= (TCR_MASTER_WRITE | (pmsg->addr & TCR_SLAVE_ADDR_MASK)); | |
170 | ||
171 | writew(tcr_val, i2c_dev->base + REG_TCR); | |
172 | ||
173 | if (pmsg->flags & I2C_M_NOSTART) { | |
174 | val = readw(i2c_dev->base + REG_CR); | |
175 | val |= CR_CPU_RDY; | |
176 | writew(val, i2c_dev->base + REG_CR); | |
177 | } | |
178 | ||
179 | while (xfer_len < pmsg->len) { | |
180 | wait_result = wait_for_completion_timeout(&i2c_dev->complete, | |
181 | msecs_to_jiffies(500)); | |
182 | ||
183 | if (wait_result == 0) | |
184 | return -ETIMEDOUT; | |
185 | ||
186 | ret = wmt_check_status(i2c_dev); | |
187 | if (ret) | |
188 | return ret; | |
189 | ||
190 | xfer_len++; | |
191 | ||
192 | val = readw(i2c_dev->base + REG_CSR); | |
193 | if ((val & CSR_RCV_ACK_MASK) == CSR_RCV_NOT_ACK) { | |
194 | dev_dbg(i2c_dev->dev, "write RCV NACK error\n"); | |
195 | return -EIO; | |
196 | } | |
197 | ||
198 | if (pmsg->len == 0) { | |
199 | val = CR_TX_END | CR_CPU_RDY | CR_ENABLE; | |
200 | writew(val, i2c_dev->base + REG_CR); | |
201 | break; | |
202 | } | |
203 | ||
204 | if (xfer_len == pmsg->len) { | |
205 | if (last != 1) | |
206 | writew(CR_ENABLE, i2c_dev->base + REG_CR); | |
207 | } else { | |
208 | writew(pmsg->buf[xfer_len] & 0xFF, i2c_dev->base + | |
209 | REG_CDR); | |
210 | writew(CR_CPU_RDY | CR_ENABLE, i2c_dev->base + REG_CR); | |
211 | } | |
212 | } | |
213 | ||
214 | return 0; | |
215 | } | |
216 | ||
217 | static int wmt_i2c_read(struct i2c_adapter *adap, struct i2c_msg *pmsg, | |
218 | int last) | |
219 | { | |
220 | struct wmt_i2c_dev *i2c_dev = i2c_get_adapdata(adap); | |
221 | u16 val, tcr_val; | |
222 | int ret; | |
223 | unsigned long wait_result; | |
224 | u32 xfer_len = 0; | |
225 | ||
226 | if (!(pmsg->flags & I2C_M_NOSTART)) { | |
227 | ret = wmt_i2c_wait_bus_not_busy(i2c_dev); | |
228 | if (ret < 0) | |
229 | return ret; | |
230 | } | |
231 | ||
232 | val = readw(i2c_dev->base + REG_CR); | |
233 | val &= ~CR_TX_END; | |
234 | writew(val, i2c_dev->base + REG_CR); | |
235 | ||
236 | val = readw(i2c_dev->base + REG_CR); | |
237 | val &= ~CR_TX_NEXT_NO_ACK; | |
238 | writew(val, i2c_dev->base + REG_CR); | |
239 | ||
240 | if (!(pmsg->flags & I2C_M_NOSTART)) { | |
241 | val = readw(i2c_dev->base + REG_CR); | |
242 | val |= CR_CPU_RDY; | |
243 | writew(val, i2c_dev->base + REG_CR); | |
244 | } | |
245 | ||
246 | if (pmsg->len == 1) { | |
247 | val = readw(i2c_dev->base + REG_CR); | |
248 | val |= CR_TX_NEXT_NO_ACK; | |
249 | writew(val, i2c_dev->base + REG_CR); | |
250 | } | |
251 | ||
252 | reinit_completion(&i2c_dev->complete); | |
253 | ||
254 | if (i2c_dev->mode == I2C_MODE_STANDARD) | |
255 | tcr_val = TCR_STANDARD_MODE; | |
256 | else | |
257 | tcr_val = TCR_FAST_MODE; | |
258 | ||
259 | tcr_val |= TCR_MASTER_READ | (pmsg->addr & TCR_SLAVE_ADDR_MASK); | |
260 | ||
261 | writew(tcr_val, i2c_dev->base + REG_TCR); | |
262 | ||
263 | if (pmsg->flags & I2C_M_NOSTART) { | |
264 | val = readw(i2c_dev->base + REG_CR); | |
265 | val |= CR_CPU_RDY; | |
266 | writew(val, i2c_dev->base + REG_CR); | |
267 | } | |
268 | ||
269 | while (xfer_len < pmsg->len) { | |
270 | wait_result = wait_for_completion_timeout(&i2c_dev->complete, | |
271 | msecs_to_jiffies(500)); | |
272 | ||
273 | if (!wait_result) | |
274 | return -ETIMEDOUT; | |
275 | ||
276 | ret = wmt_check_status(i2c_dev); | |
277 | if (ret) | |
278 | return ret; | |
279 | ||
280 | pmsg->buf[xfer_len] = readw(i2c_dev->base + REG_CDR) >> 8; | |
281 | xfer_len++; | |
282 | ||
283 | if (xfer_len == pmsg->len - 1) { | |
284 | val = readw(i2c_dev->base + REG_CR); | |
285 | val |= (CR_TX_NEXT_NO_ACK | CR_CPU_RDY); | |
286 | writew(val, i2c_dev->base + REG_CR); | |
287 | } else { | |
288 | val = readw(i2c_dev->base + REG_CR); | |
289 | val |= CR_CPU_RDY; | |
290 | writew(val, i2c_dev->base + REG_CR); | |
291 | } | |
292 | } | |
293 | ||
294 | return 0; | |
295 | } | |
296 | ||
297 | static int wmt_i2c_xfer(struct i2c_adapter *adap, | |
298 | struct i2c_msg msgs[], | |
299 | int num) | |
300 | { | |
301 | struct i2c_msg *pmsg; | |
302 | int i, is_last; | |
303 | int ret = 0; | |
304 | ||
305 | for (i = 0; ret >= 0 && i < num; i++) { | |
306 | is_last = ((i + 1) == num); | |
307 | ||
308 | pmsg = &msgs[i]; | |
309 | if (pmsg->flags & I2C_M_RD) | |
310 | ret = wmt_i2c_read(adap, pmsg, is_last); | |
311 | else | |
312 | ret = wmt_i2c_write(adap, pmsg, is_last); | |
313 | } | |
314 | ||
315 | return (ret < 0) ? ret : i; | |
316 | } | |
317 | ||
318 | static u32 wmt_i2c_func(struct i2c_adapter *adap) | |
319 | { | |
320 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART; | |
321 | } | |
322 | ||
323 | static const struct i2c_algorithm wmt_i2c_algo = { | |
324 | .master_xfer = wmt_i2c_xfer, | |
325 | .functionality = wmt_i2c_func, | |
326 | }; | |
327 | ||
328 | static irqreturn_t wmt_i2c_isr(int irq, void *data) | |
329 | { | |
330 | struct wmt_i2c_dev *i2c_dev = data; | |
331 | ||
332 | /* save the status and write-clear it */ | |
333 | i2c_dev->cmd_status = readw(i2c_dev->base + REG_ISR); | |
334 | writew(i2c_dev->cmd_status, i2c_dev->base + REG_ISR); | |
335 | ||
336 | complete(&i2c_dev->complete); | |
337 | ||
338 | return IRQ_HANDLED; | |
339 | } | |
340 | ||
341 | static int wmt_i2c_reset_hardware(struct wmt_i2c_dev *i2c_dev) | |
342 | { | |
343 | int err; | |
344 | ||
345 | err = clk_prepare_enable(i2c_dev->clk); | |
346 | if (err) { | |
347 | dev_err(i2c_dev->dev, "failed to enable clock\n"); | |
348 | return err; | |
349 | } | |
350 | ||
351 | err = clk_set_rate(i2c_dev->clk, 20000000); | |
352 | if (err) { | |
353 | dev_err(i2c_dev->dev, "failed to set clock = 20Mhz\n"); | |
354 | clk_disable_unprepare(i2c_dev->clk); | |
355 | return err; | |
356 | } | |
357 | ||
358 | writew(0, i2c_dev->base + REG_CR); | |
359 | writew(MCR_APB_166M, i2c_dev->base + REG_MCR); | |
360 | writew(ISR_WRITE_ALL, i2c_dev->base + REG_ISR); | |
361 | writew(IMR_ENABLE_ALL, i2c_dev->base + REG_IMR); | |
362 | writew(CR_ENABLE, i2c_dev->base + REG_CR); | |
363 | readw(i2c_dev->base + REG_CSR); /* read clear */ | |
364 | writew(ISR_WRITE_ALL, i2c_dev->base + REG_ISR); | |
365 | ||
366 | if (i2c_dev->mode == I2C_MODE_STANDARD) | |
367 | writew(SCL_TIMEOUT(128) | TR_STD, i2c_dev->base + REG_TR); | |
368 | else | |
369 | writew(SCL_TIMEOUT(128) | TR_HS, i2c_dev->base + REG_TR); | |
370 | ||
371 | return 0; | |
372 | } | |
373 | ||
374 | static int wmt_i2c_probe(struct platform_device *pdev) | |
375 | { | |
376 | struct device_node *np = pdev->dev.of_node; | |
377 | struct wmt_i2c_dev *i2c_dev; | |
378 | struct i2c_adapter *adap; | |
379 | struct resource *res; | |
380 | int err; | |
381 | u32 clk_rate; | |
382 | ||
383 | i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); | |
384 | if (!i2c_dev) | |
385 | return -ENOMEM; | |
386 | ||
387 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
388 | i2c_dev->base = devm_ioremap_resource(&pdev->dev, res); | |
389 | if (IS_ERR(i2c_dev->base)) | |
390 | return PTR_ERR(i2c_dev->base); | |
391 | ||
392 | i2c_dev->irq = irq_of_parse_and_map(np, 0); | |
393 | if (!i2c_dev->irq) { | |
394 | dev_err(&pdev->dev, "irq missing or invalid\n"); | |
395 | return -EINVAL; | |
396 | } | |
397 | ||
398 | i2c_dev->clk = of_clk_get(np, 0); | |
399 | if (IS_ERR(i2c_dev->clk)) { | |
400 | dev_err(&pdev->dev, "unable to request clock\n"); | |
401 | return PTR_ERR(i2c_dev->clk); | |
402 | } | |
403 | ||
404 | i2c_dev->mode = I2C_MODE_STANDARD; | |
405 | err = of_property_read_u32(np, "clock-frequency", &clk_rate); | |
406 | if ((!err) && (clk_rate == 400000)) | |
407 | i2c_dev->mode = I2C_MODE_FAST; | |
408 | ||
409 | i2c_dev->dev = &pdev->dev; | |
410 | ||
411 | err = devm_request_irq(&pdev->dev, i2c_dev->irq, wmt_i2c_isr, 0, | |
412 | "i2c", i2c_dev); | |
413 | if (err) { | |
414 | dev_err(&pdev->dev, "failed to request irq %i\n", i2c_dev->irq); | |
415 | return err; | |
416 | } | |
417 | ||
418 | adap = &i2c_dev->adapter; | |
419 | i2c_set_adapdata(adap, i2c_dev); | |
420 | strlcpy(adap->name, "WMT I2C adapter", sizeof(adap->name)); | |
421 | adap->owner = THIS_MODULE; | |
422 | adap->algo = &wmt_i2c_algo; | |
423 | adap->dev.parent = &pdev->dev; | |
424 | adap->dev.of_node = pdev->dev.of_node; | |
425 | ||
426 | init_completion(&i2c_dev->complete); | |
427 | ||
428 | err = wmt_i2c_reset_hardware(i2c_dev); | |
429 | if (err) { | |
430 | dev_err(&pdev->dev, "error initializing hardware\n"); | |
431 | return err; | |
432 | } | |
433 | ||
434 | err = i2c_add_adapter(adap); | |
435 | if (err) | |
436 | return err; | |
437 | ||
438 | platform_set_drvdata(pdev, i2c_dev); | |
439 | ||
440 | return 0; | |
441 | } | |
442 | ||
443 | static int wmt_i2c_remove(struct platform_device *pdev) | |
444 | { | |
445 | struct wmt_i2c_dev *i2c_dev = platform_get_drvdata(pdev); | |
446 | ||
447 | /* Disable interrupts, clock and delete adapter */ | |
448 | writew(0, i2c_dev->base + REG_IMR); | |
449 | clk_disable_unprepare(i2c_dev->clk); | |
450 | i2c_del_adapter(&i2c_dev->adapter); | |
451 | ||
452 | return 0; | |
453 | } | |
454 | ||
455 | static const struct of_device_id wmt_i2c_dt_ids[] = { | |
456 | { .compatible = "wm,wm8505-i2c" }, | |
457 | { /* Sentinel */ }, | |
458 | }; | |
459 | ||
460 | static struct platform_driver wmt_i2c_driver = { | |
461 | .probe = wmt_i2c_probe, | |
462 | .remove = wmt_i2c_remove, | |
463 | .driver = { | |
464 | .name = "wmt-i2c", | |
465 | .of_match_table = wmt_i2c_dt_ids, | |
466 | }, | |
467 | }; | |
468 | ||
469 | module_platform_driver(wmt_i2c_driver); | |
470 | ||
471 | MODULE_DESCRIPTION("Wondermedia I2C master-mode bus adapter"); | |
472 | MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>"); | |
473 | MODULE_LICENSE("GPL"); | |
474 | MODULE_DEVICE_TABLE(of, wmt_i2c_dt_ids); |