Merge remote-tracking branch 'spi/fix/core' into spi-linus
[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / i2c / busses / i2c-wmt.c
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, wait_result;
132         int xfer_len = 0;
133
134         if (!(pmsg->flags & I2C_M_NOSTART)) {
135                 ret = wmt_i2c_wait_bus_not_busy(i2c_dev);
136                 if (ret < 0)
137                         return ret;
138         }
139
140         if (pmsg->len == 0) {
141                 /*
142                  * We still need to run through the while (..) once, so
143                  * start at -1 and break out early from the loop
144                  */
145                 xfer_len = -1;
146                 writew(0, i2c_dev->base + REG_CDR);
147         } else {
148                 writew(pmsg->buf[0] & 0xFF, i2c_dev->base + REG_CDR);
149         }
150
151         if (!(pmsg->flags & I2C_M_NOSTART)) {
152                 val = readw(i2c_dev->base + REG_CR);
153                 val &= ~CR_TX_END;
154                 writew(val, i2c_dev->base + REG_CR);
155
156                 val = readw(i2c_dev->base + REG_CR);
157                 val |= CR_CPU_RDY;
158                 writew(val, i2c_dev->base + REG_CR);
159         }
160
161         reinit_completion(&i2c_dev->complete);
162
163         if (i2c_dev->mode == I2C_MODE_STANDARD)
164                 tcr_val = TCR_STANDARD_MODE;
165         else
166                 tcr_val = TCR_FAST_MODE;
167
168         tcr_val |= (TCR_MASTER_WRITE | (pmsg->addr & TCR_SLAVE_ADDR_MASK));
169
170         writew(tcr_val, i2c_dev->base + REG_TCR);
171
172         if (pmsg->flags & I2C_M_NOSTART) {
173                 val = readw(i2c_dev->base + REG_CR);
174                 val |= CR_CPU_RDY;
175                 writew(val, i2c_dev->base + REG_CR);
176         }
177
178         while (xfer_len < pmsg->len) {
179                 wait_result = wait_for_completion_timeout(&i2c_dev->complete,
180                                                           500 * HZ / 1000);
181
182                 if (wait_result == 0)
183                         return -ETIMEDOUT;
184
185                 ret = wmt_check_status(i2c_dev);
186                 if (ret)
187                         return ret;
188
189                 xfer_len++;
190
191                 val = readw(i2c_dev->base + REG_CSR);
192                 if ((val & CSR_RCV_ACK_MASK) == CSR_RCV_NOT_ACK) {
193                         dev_dbg(i2c_dev->dev, "write RCV NACK error\n");
194                         return -EIO;
195                 }
196
197                 if (pmsg->len == 0) {
198                         val = CR_TX_END | CR_CPU_RDY | CR_ENABLE;
199                         writew(val, i2c_dev->base + REG_CR);
200                         break;
201                 }
202
203                 if (xfer_len == pmsg->len) {
204                         if (last != 1)
205                                 writew(CR_ENABLE, i2c_dev->base + REG_CR);
206                 } else {
207                         writew(pmsg->buf[xfer_len] & 0xFF, i2c_dev->base +
208                                                                 REG_CDR);
209                         writew(CR_CPU_RDY | CR_ENABLE, i2c_dev->base + REG_CR);
210                 }
211         }
212
213         return 0;
214 }
215
216 static int wmt_i2c_read(struct i2c_adapter *adap, struct i2c_msg *pmsg,
217                         int last)
218 {
219         struct wmt_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
220         u16 val, tcr_val;
221         int ret, wait_result;
222         u32 xfer_len = 0;
223
224         if (!(pmsg->flags & I2C_M_NOSTART)) {
225                 ret = wmt_i2c_wait_bus_not_busy(i2c_dev);
226                 if (ret < 0)
227                         return ret;
228         }
229
230         val = readw(i2c_dev->base + REG_CR);
231         val &= ~CR_TX_END;
232         writew(val, i2c_dev->base + REG_CR);
233
234         val = readw(i2c_dev->base + REG_CR);
235         val &= ~CR_TX_NEXT_NO_ACK;
236         writew(val, i2c_dev->base + REG_CR);
237
238         if (!(pmsg->flags & I2C_M_NOSTART)) {
239                 val = readw(i2c_dev->base + REG_CR);
240                 val |= CR_CPU_RDY;
241                 writew(val, i2c_dev->base + REG_CR);
242         }
243
244         if (pmsg->len == 1) {
245                 val = readw(i2c_dev->base + REG_CR);
246                 val |= CR_TX_NEXT_NO_ACK;
247                 writew(val, i2c_dev->base + REG_CR);
248         }
249
250         reinit_completion(&i2c_dev->complete);
251
252         if (i2c_dev->mode == I2C_MODE_STANDARD)
253                 tcr_val = TCR_STANDARD_MODE;
254         else
255                 tcr_val = TCR_FAST_MODE;
256
257         tcr_val |= TCR_MASTER_READ | (pmsg->addr & TCR_SLAVE_ADDR_MASK);
258
259         writew(tcr_val, i2c_dev->base + REG_TCR);
260
261         if (pmsg->flags & I2C_M_NOSTART) {
262                 val = readw(i2c_dev->base + REG_CR);
263                 val |= CR_CPU_RDY;
264                 writew(val, i2c_dev->base + REG_CR);
265         }
266
267         while (xfer_len < pmsg->len) {
268                 wait_result = wait_for_completion_timeout(&i2c_dev->complete,
269                                                           500 * HZ / 1000);
270
271                 if (!wait_result)
272                         return -ETIMEDOUT;
273
274                 ret = wmt_check_status(i2c_dev);
275                 if (ret)
276                         return ret;
277
278                 pmsg->buf[xfer_len] = readw(i2c_dev->base + REG_CDR) >> 8;
279                 xfer_len++;
280
281                 if (xfer_len == pmsg->len - 1) {
282                         val = readw(i2c_dev->base + REG_CR);
283                         val |= (CR_TX_NEXT_NO_ACK | CR_CPU_RDY);
284                         writew(val, i2c_dev->base + REG_CR);
285                 } else {
286                         val = readw(i2c_dev->base + REG_CR);
287                         val |= CR_CPU_RDY;
288                         writew(val, i2c_dev->base + REG_CR);
289                 }
290         }
291
292         return 0;
293 }
294
295 static int wmt_i2c_xfer(struct i2c_adapter *adap,
296                         struct i2c_msg msgs[],
297                         int num)
298 {
299         struct i2c_msg *pmsg;
300         int i, is_last;
301         int ret = 0;
302
303         for (i = 0; ret >= 0 && i < num; i++) {
304                 is_last = ((i + 1) == num);
305
306                 pmsg = &msgs[i];
307                 if (pmsg->flags & I2C_M_RD)
308                         ret = wmt_i2c_read(adap, pmsg, is_last);
309                 else
310                         ret = wmt_i2c_write(adap, pmsg, is_last);
311         }
312
313         return (ret < 0) ? ret : i;
314 }
315
316 static u32 wmt_i2c_func(struct i2c_adapter *adap)
317 {
318         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART;
319 }
320
321 static const struct i2c_algorithm wmt_i2c_algo = {
322         .master_xfer    = wmt_i2c_xfer,
323         .functionality  = wmt_i2c_func,
324 };
325
326 static irqreturn_t wmt_i2c_isr(int irq, void *data)
327 {
328         struct wmt_i2c_dev *i2c_dev = data;
329
330         /* save the status and write-clear it */
331         i2c_dev->cmd_status = readw(i2c_dev->base + REG_ISR);
332         writew(i2c_dev->cmd_status, i2c_dev->base + REG_ISR);
333
334         complete(&i2c_dev->complete);
335
336         return IRQ_HANDLED;
337 }
338
339 static int wmt_i2c_reset_hardware(struct wmt_i2c_dev *i2c_dev)
340 {
341         int err;
342
343         err = clk_prepare_enable(i2c_dev->clk);
344         if (err) {
345                 dev_err(i2c_dev->dev, "failed to enable clock\n");
346                 return err;
347         }
348
349         err = clk_set_rate(i2c_dev->clk, 20000000);
350         if (err) {
351                 dev_err(i2c_dev->dev, "failed to set clock = 20Mhz\n");
352                 clk_disable_unprepare(i2c_dev->clk);
353                 return err;
354         }
355
356         writew(0, i2c_dev->base + REG_CR);
357         writew(MCR_APB_166M, i2c_dev->base + REG_MCR);
358         writew(ISR_WRITE_ALL, i2c_dev->base + REG_ISR);
359         writew(IMR_ENABLE_ALL, i2c_dev->base + REG_IMR);
360         writew(CR_ENABLE, i2c_dev->base + REG_CR);
361         readw(i2c_dev->base + REG_CSR);         /* read clear */
362         writew(ISR_WRITE_ALL, i2c_dev->base + REG_ISR);
363
364         if (i2c_dev->mode == I2C_MODE_STANDARD)
365                 writew(SCL_TIMEOUT(128) | TR_STD, i2c_dev->base + REG_TR);
366         else
367                 writew(SCL_TIMEOUT(128) | TR_HS, i2c_dev->base + REG_TR);
368
369         return 0;
370 }
371
372 static int wmt_i2c_probe(struct platform_device *pdev)
373 {
374         struct device_node *np = pdev->dev.of_node;
375         struct wmt_i2c_dev *i2c_dev;
376         struct i2c_adapter *adap;
377         struct resource *res;
378         int err;
379         u32 clk_rate;
380
381         i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
382         if (!i2c_dev) {
383                 dev_err(&pdev->dev, "device memory allocation failed\n");
384                 return -ENOMEM;
385         }
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                 dev_err(&pdev->dev, "failed to add adapter\n");
437                 return err;
438         }
439
440         platform_set_drvdata(pdev, i2c_dev);
441
442         return 0;
443 }
444
445 static int wmt_i2c_remove(struct platform_device *pdev)
446 {
447         struct wmt_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
448
449         /* Disable interrupts, clock and delete adapter */
450         writew(0, i2c_dev->base + REG_IMR);
451         clk_disable_unprepare(i2c_dev->clk);
452         i2c_del_adapter(&i2c_dev->adapter);
453
454         return 0;
455 }
456
457 static struct of_device_id wmt_i2c_dt_ids[] = {
458         { .compatible = "wm,wm8505-i2c" },
459         { /* Sentinel */ },
460 };
461
462 static struct platform_driver wmt_i2c_driver = {
463         .probe          = wmt_i2c_probe,
464         .remove         = wmt_i2c_remove,
465         .driver         = {
466                 .name   = "wmt-i2c",
467                 .owner  = THIS_MODULE,
468                 .of_match_table = wmt_i2c_dt_ids,
469         },
470 };
471
472 module_platform_driver(wmt_i2c_driver);
473
474 MODULE_DESCRIPTION("Wondermedia I2C master-mode bus adapter");
475 MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>");
476 MODULE_LICENSE("GPL");
477 MODULE_DEVICE_TABLE(of, wmt_i2c_dt_ids);