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x86/boot: Rename overlapping memcpy() to memmove()
[linux/fpc-iii.git] / drivers / i2c / busses / i2c-axxia.c
blobc335cc7852f94ef0b08525901c03eb8b38ec76ae
1 /*
2 * This driver implements I2C master functionality using the LSI API2C
3 * controller.
4 *
5 * NOTE: The controller has a limitation in that it can only do transfers of
6 * maximum 255 bytes at a time. If a larger transfer is attempted, error code
7 * (-EINVAL) is returned.
8 *
9 * This software is licensed under the terms of the GNU General Public
10 * License version 2, as published by the Free Software Foundation, and
11 * may be copied, distributed, and modified under those terms.
12 */
13 #include <linux/clk.h>
14 #include <linux/clkdev.h>
15 #include <linux/err.h>
16 #include <linux/i2c.h>
17 #include <linux/init.h>
18 #include <linux/interrupt.h>
19 #include <linux/module.h>
20 #include <linux/io.h>
21 #include <linux/kernel.h>
22 #include <linux/platform_device.h>
23
24 #define SCL_WAIT_TIMEOUT_NS 25000000
25 #define I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
26 #define I2C_STOP_TIMEOUT (msecs_to_jiffies(100))
27 #define FIFO_SIZE 8
28
29 #define GLOBAL_CONTROL 0x00
30 #define GLOBAL_MST_EN BIT(0)
31 #define GLOBAL_SLV_EN BIT(1)
32 #define GLOBAL_IBML_EN BIT(2)
33 #define INTERRUPT_STATUS 0x04
34 #define INTERRUPT_ENABLE 0x08
35 #define INT_SLV BIT(1)
36 #define INT_MST BIT(0)
37 #define WAIT_TIMER_CONTROL 0x0c
38 #define WT_EN BIT(15)
39 #define WT_VALUE(_x) ((_x) & 0x7fff)
40 #define IBML_TIMEOUT 0x10
41 #define IBML_LOW_MEXT 0x14
42 #define IBML_LOW_SEXT 0x18
43 #define TIMER_CLOCK_DIV 0x1c
44 #define I2C_BUS_MONITOR 0x20
45 #define BM_SDAC BIT(3)
46 #define BM_SCLC BIT(2)
47 #define BM_SDAS BIT(1)
48 #define BM_SCLS BIT(0)
49 #define SOFT_RESET 0x24
50 #define MST_COMMAND 0x28
51 #define CMD_BUSY (1<<3)
52 #define CMD_MANUAL (0x00 | CMD_BUSY)
53 #define CMD_AUTO (0x01 | CMD_BUSY)
54 #define MST_RX_XFER 0x2c
55 #define MST_TX_XFER 0x30
56 #define MST_ADDR_1 0x34
57 #define MST_ADDR_2 0x38
58 #define MST_DATA 0x3c
59 #define MST_TX_FIFO 0x40
60 #define MST_RX_FIFO 0x44
61 #define MST_INT_ENABLE 0x48
62 #define MST_INT_STATUS 0x4c
63 #define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */
64 #define MST_STATUS_TFL (1 << 12) /* TX FIFO service */
65 #define MST_STATUS_SNS (1 << 11) /* Manual mode done */
66 #define MST_STATUS_SS (1 << 10) /* Automatic mode done */
67 #define MST_STATUS_SCC (1 << 9) /* Stop complete */
68 #define MST_STATUS_IP (1 << 8) /* Invalid parameter */
69 #define MST_STATUS_TSS (1 << 7) /* Timeout */
70 #define MST_STATUS_AL (1 << 6) /* Arbitration lost */
71 #define MST_STATUS_ND (1 << 5) /* NAK on data phase */
72 #define MST_STATUS_NA (1 << 4) /* NAK on address phase */
73 #define MST_STATUS_NAK (MST_STATUS_NA | \
74 MST_STATUS_ND)
75 #define MST_STATUS_ERR (MST_STATUS_NAK | \
76 MST_STATUS_AL | \
77 MST_STATUS_IP | \
78 MST_STATUS_TSS)
79 #define MST_TX_BYTES_XFRD 0x50
80 #define MST_RX_BYTES_XFRD 0x54
81 #define SCL_HIGH_PERIOD 0x80
82 #define SCL_LOW_PERIOD 0x84
83 #define SPIKE_FLTR_LEN 0x88
84 #define SDA_SETUP_TIME 0x8c
85 #define SDA_HOLD_TIME 0x90
86
87 /**
88 * axxia_i2c_dev - I2C device context
89 * @base: pointer to register struct
90 * @msg: pointer to current message
91 * @msg_xfrd: number of bytes transferred in msg
92 * @msg_err: error code for completed message
93 * @msg_complete: xfer completion object
94 * @dev: device reference
95 * @adapter: core i2c abstraction
96 * @i2c_clk: clock reference for i2c input clock
97 * @bus_clk_rate: current i2c bus clock rate
98 */
99 struct axxia_i2c_dev {
100 void __iomem *base;
101 struct i2c_msg *msg;
102 size_t msg_xfrd;
103 int msg_err;
104 struct completion msg_complete;
105 struct device *dev;
106 struct i2c_adapter adapter;
107 struct clk *i2c_clk;
108 u32 bus_clk_rate;
109 };
110
111 static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
112 {
113 u32 int_en;
114
115 int_en = readl(idev->base + MST_INT_ENABLE);
116 writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
117 }
118
119 static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
120 {
121 u32 int_en;
122
123 int_en = readl(idev->base + MST_INT_ENABLE);
124 writel(int_en | mask, idev->base + MST_INT_ENABLE);
125 }
126
127 /**
128 * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
129 */
130 static u32 ns_to_clk(u64 ns, u32 clk_mhz)
131 {
132 return div_u64(ns * clk_mhz, 1000);
133 }
134
135 static int axxia_i2c_init(struct axxia_i2c_dev *idev)
136 {
137 u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
138 u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
139 u32 t_setup;
140 u32 t_high, t_low;
141 u32 tmo_clk;
142 u32 prescale;
143 unsigned long timeout;
144
145 dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
146 idev->bus_clk_rate, clk_mhz, divisor);
147
148 /* Reset controller */
149 writel(0x01, idev->base + SOFT_RESET);
150 timeout = jiffies + msecs_to_jiffies(100);
151 while (readl(idev->base + SOFT_RESET) & 1) {
152 if (time_after(jiffies, timeout)) {
153 dev_warn(idev->dev, "Soft reset failed\n");
154 break;
155 }
156 }
157
158 /* Enable Master Mode */
159 writel(0x1, idev->base + GLOBAL_CONTROL);
160
161 if (idev->bus_clk_rate <= 100000) {
162 /* Standard mode SCL 50/50, tSU:DAT = 250 ns */
163 t_high = divisor * 1 / 2;
164 t_low = divisor * 1 / 2;
165 t_setup = ns_to_clk(250, clk_mhz);
166 } else {
167 /* Fast mode SCL 33/66, tSU:DAT = 100 ns */
168 t_high = divisor * 1 / 3;
169 t_low = divisor * 2 / 3;
170 t_setup = ns_to_clk(100, clk_mhz);
171 }
172
173 /* SCL High Time */
174 writel(t_high, idev->base + SCL_HIGH_PERIOD);
175 /* SCL Low Time */
176 writel(t_low, idev->base + SCL_LOW_PERIOD);
177 /* SDA Setup Time */
178 writel(t_setup, idev->base + SDA_SETUP_TIME);
179 /* SDA Hold Time, 300ns */
180 writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
181 /* Filter <50ns spikes */
182 writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
183
184 /* Configure Time-Out Registers */
185 tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
186
187 /* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
188 for (prescale = 0; prescale < 15; ++prescale) {
189 if (tmo_clk <= 0x7fff)
190 break;
191 tmo_clk >>= 1;
192 }
193 if (tmo_clk > 0x7fff)
194 tmo_clk = 0x7fff;
195
196 /* Prescale divider (log2) */
197 writel(prescale, idev->base + TIMER_CLOCK_DIV);
198 /* Timeout in divided clocks */
199 writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
200
201 /* Mask all master interrupt bits */
202 i2c_int_disable(idev, ~0);
203
204 /* Interrupt enable */
205 writel(0x01, idev->base + INTERRUPT_ENABLE);
206
207 return 0;
208 }
209
210 static int i2c_m_rd(const struct i2c_msg *msg)
211 {
212 return (msg->flags & I2C_M_RD) != 0;
213 }
214
215 static int i2c_m_ten(const struct i2c_msg *msg)
216 {
217 return (msg->flags & I2C_M_TEN) != 0;
218 }
219
220 static int i2c_m_recv_len(const struct i2c_msg *msg)
221 {
222 return (msg->flags & I2C_M_RECV_LEN) != 0;
223 }
224
225 /**
226 * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
227 * transfer length if this is the first byte of such a transfer.
228 */
229 static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
230 {
231 struct i2c_msg *msg = idev->msg;
232 size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
233 int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd);
234
235 while (bytes_to_transfer-- > 0) {
236 int c = readl(idev->base + MST_DATA);
237
238 if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) {
239 /*
240 * Check length byte for SMBus block read
241 */
242 if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
243 idev->msg_err = -EPROTO;
244 i2c_int_disable(idev, ~0);
245 complete(&idev->msg_complete);
246 break;
247 }
248 msg->len = 1 + c;
249 writel(msg->len, idev->base + MST_RX_XFER);
250 }
251 msg->buf[idev->msg_xfrd++] = c;
252 }
253
254 return 0;
255 }
256
257 /**
258 * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
259 * @return: Number of bytes left to transfer.
260 */
261 static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
262 {
263 struct i2c_msg *msg = idev->msg;
264 size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
265 int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
266 int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
267
268 while (bytes_to_transfer-- > 0)
269 writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
270
271 return ret;
272 }
273
274 static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
275 {
276 struct axxia_i2c_dev *idev = _dev;
277 u32 status;
278
279 if (!(readl(idev->base + INTERRUPT_STATUS) & INT_MST))
280 return IRQ_NONE;
281
282 /* Read interrupt status bits */
283 status = readl(idev->base + MST_INT_STATUS);
284
285 if (!idev->msg) {
286 dev_warn(idev->dev, "unexpected interrupt\n");
287 goto out;
288 }
289
290 /* RX FIFO needs service? */
291 if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
292 axxia_i2c_empty_rx_fifo(idev);
293
294 /* TX FIFO needs service? */
295 if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
296 if (axxia_i2c_fill_tx_fifo(idev) == 0)
297 i2c_int_disable(idev, MST_STATUS_TFL);
298 }
299
300 if (status & MST_STATUS_SCC) {
301 /* Stop completed */
302 i2c_int_disable(idev, ~0);
303 complete(&idev->msg_complete);
304 } else if (status & MST_STATUS_SNS) {
305 /* Transfer done */
306 i2c_int_disable(idev, ~0);
307 if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
308 axxia_i2c_empty_rx_fifo(idev);
309 complete(&idev->msg_complete);
310 } else if (unlikely(status & MST_STATUS_ERR)) {
311 /* Transfer error */
312 i2c_int_disable(idev, ~0);
313 if (status & MST_STATUS_AL)
314 idev->msg_err = -EAGAIN;
315 else if (status & MST_STATUS_NAK)
316 idev->msg_err = -ENXIO;
317 else
318 idev->msg_err = -EIO;
319 dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
320 status,
321 idev->msg->addr,
322 readl(idev->base + MST_RX_BYTES_XFRD),
323 readl(idev->base + MST_RX_XFER),
324 readl(idev->base + MST_TX_BYTES_XFRD),
325 readl(idev->base + MST_TX_XFER));
326 complete(&idev->msg_complete);
327 }
328
329 out:
330 /* Clear interrupt */
331 writel(INT_MST, idev->base + INTERRUPT_STATUS);
332
333 return IRQ_HANDLED;
334 }
335
336 static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
337 {
338 u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS;
339 u32 rx_xfer, tx_xfer;
340 u32 addr_1, addr_2;
341 unsigned long time_left;
342
343 idev->msg = msg;
344 idev->msg_xfrd = 0;
345 idev->msg_err = 0;
346 reinit_completion(&idev->msg_complete);
347
348 if (i2c_m_ten(msg)) {
349 /* 10-bit address
350 * addr_1: 5'b11110 | addr[9:8] | (R/nW)
351 * addr_2: addr[7:0]
352 */
353 addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
354 addr_2 = msg->addr & 0xFF;
355 } else {
356 /* 7-bit address
357 * addr_1: addr[6:0] | (R/nW)
358 * addr_2: dont care
359 */
360 addr_1 = (msg->addr << 1) & 0xFF;
361 addr_2 = 0;
362 }
363
364 if (i2c_m_rd(msg)) {
365 /* I2C read transfer */
366 rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
367 tx_xfer = 0;
368 addr_1 |= 1; /* Set the R/nW bit of the address */
369 } else {
370 /* I2C write transfer */
371 rx_xfer = 0;
372 tx_xfer = msg->len;
373 }
374
375 writel(rx_xfer, idev->base + MST_RX_XFER);
376 writel(tx_xfer, idev->base + MST_TX_XFER);
377 writel(addr_1, idev->base + MST_ADDR_1);
378 writel(addr_2, idev->base + MST_ADDR_2);
379
380 if (i2c_m_rd(msg))
381 int_mask |= MST_STATUS_RFL;
382 else if (axxia_i2c_fill_tx_fifo(idev) != 0)
383 int_mask |= MST_STATUS_TFL;
384
385 /* Start manual mode */
386 writel(CMD_MANUAL, idev->base + MST_COMMAND);
387
388 i2c_int_enable(idev, int_mask);
389
390 time_left = wait_for_completion_timeout(&idev->msg_complete,
391 I2C_XFER_TIMEOUT);
392
393 i2c_int_disable(idev, int_mask);
394
395 if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
396 dev_warn(idev->dev, "busy after xfer\n");
397
398 if (time_left == 0)
399 idev->msg_err = -ETIMEDOUT;
400
401 if (idev->msg_err == -ETIMEDOUT)
402 i2c_recover_bus(&idev->adapter);
403
404 if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
405 axxia_i2c_init(idev);
406
407 return idev->msg_err;
408 }
409
410 static int axxia_i2c_stop(struct axxia_i2c_dev *idev)
411 {
412 u32 int_mask = MST_STATUS_ERR | MST_STATUS_SCC;
413 unsigned long time_left;
414
415 reinit_completion(&idev->msg_complete);
416
417 /* Issue stop */
418 writel(0xb, idev->base + MST_COMMAND);
419 i2c_int_enable(idev, int_mask);
420 time_left = wait_for_completion_timeout(&idev->msg_complete,
421 I2C_STOP_TIMEOUT);
422 i2c_int_disable(idev, int_mask);
423 if (time_left == 0)
424 return -ETIMEDOUT;
425
426 if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
427 dev_warn(idev->dev, "busy after stop\n");
428
429 return 0;
430 }
431
432 static int
433 axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
434 {
435 struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
436 int i;
437 int ret = 0;
438
439 for (i = 0; ret == 0 && i < num; ++i)
440 ret = axxia_i2c_xfer_msg(idev, &msgs[i]);
441
442 axxia_i2c_stop(idev);
443
444 return ret ? : i;
445 }
446
447 static int axxia_i2c_get_scl(struct i2c_adapter *adap)
448 {
449 struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
450
451 return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SCLS);
452 }
453
454 static void axxia_i2c_set_scl(struct i2c_adapter *adap, int val)
455 {
456 struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
457 u32 tmp;
458
459 /* Preserve SDA Control */
460 tmp = readl(idev->base + I2C_BUS_MONITOR) & BM_SDAC;
461 if (!val)
462 tmp |= BM_SCLC;
463 writel(tmp, idev->base + I2C_BUS_MONITOR);
464 }
465
466 static int axxia_i2c_get_sda(struct i2c_adapter *adap)
467 {
468 struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
469
470 return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SDAS);
471 }
472
473 static struct i2c_bus_recovery_info axxia_i2c_recovery_info = {
474 .recover_bus = i2c_generic_scl_recovery,
475 .get_scl = axxia_i2c_get_scl,
476 .set_scl = axxia_i2c_set_scl,
477 .get_sda = axxia_i2c_get_sda,
478 };
479
480 static u32 axxia_i2c_func(struct i2c_adapter *adap)
481 {
482 u32 caps = (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
483 I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
484 return caps;
485 }
486
487 static const struct i2c_algorithm axxia_i2c_algo = {
488 .master_xfer = axxia_i2c_xfer,
489 .functionality = axxia_i2c_func,
490 };
491
492 static struct i2c_adapter_quirks axxia_i2c_quirks = {
493 .max_read_len = 255,
494 .max_write_len = 255,
495 };
496
497 static int axxia_i2c_probe(struct platform_device *pdev)
498 {
499 struct device_node *np = pdev->dev.of_node;
500 struct axxia_i2c_dev *idev = NULL;
501 struct resource *res;
502 void __iomem *base;
503 int irq;
504 int ret = 0;
505
506 idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
507 if (!idev)
508 return -ENOMEM;
509
510 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
511 base = devm_ioremap_resource(&pdev->dev, res);
512 if (IS_ERR(base))
513 return PTR_ERR(base);
514
515 irq = platform_get_irq(pdev, 0);
516 if (irq < 0) {
517 dev_err(&pdev->dev, "missing interrupt resource\n");
518 return irq;
519 }
520
521 idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
522 if (IS_ERR(idev->i2c_clk)) {
523 dev_err(&pdev->dev, "missing clock\n");
524 return PTR_ERR(idev->i2c_clk);
525 }
526
527 idev->base = base;
528 idev->dev = &pdev->dev;
529 init_completion(&idev->msg_complete);
530
531 of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
532 if (idev->bus_clk_rate == 0)
533 idev->bus_clk_rate = 100000; /* default clock rate */
534
535 ret = axxia_i2c_init(idev);
536 if (ret) {
537 dev_err(&pdev->dev, "failed to initialize\n");
538 return ret;
539 }
540
541 ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0,
542 pdev->name, idev);
543 if (ret) {
544 dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq);
545 return ret;
546 }
547
548 clk_prepare_enable(idev->i2c_clk);
549
550 i2c_set_adapdata(&idev->adapter, idev);
551 strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
552 idev->adapter.owner = THIS_MODULE;
553 idev->adapter.algo = &axxia_i2c_algo;
554 idev->adapter.bus_recovery_info = &axxia_i2c_recovery_info;
555 idev->adapter.quirks = &axxia_i2c_quirks;
556 idev->adapter.dev.parent = &pdev->dev;
557 idev->adapter.dev.of_node = pdev->dev.of_node;
558
559 platform_set_drvdata(pdev, idev);
560
561 ret = i2c_add_adapter(&idev->adapter);
562 if (ret) {
563 dev_err(&pdev->dev, "failed to add adapter\n");
564 return ret;
565 }
566
567 return 0;
568 }
569
570 static int axxia_i2c_remove(struct platform_device *pdev)
571 {
572 struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
573
574 clk_disable_unprepare(idev->i2c_clk);
575 i2c_del_adapter(&idev->adapter);
576
577 return 0;
578 }
579
580 /* Match table for of_platform binding */
581 static const struct of_device_id axxia_i2c_of_match[] = {
582 { .compatible = "lsi,api2c", },
583 {},
584 };
585
586 MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
587
588 static struct platform_driver axxia_i2c_driver = {
589 .probe = axxia_i2c_probe,
590 .remove = axxia_i2c_remove,
591 .driver = {
592 .name = "axxia-i2c",
593 .of_match_table = axxia_i2c_of_match,
594 },
595 };
596
597 module_platform_driver(axxia_i2c_driver);
598
599 MODULE_DESCRIPTION("Axxia I2C Bus driver");
600 MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
601 MODULE_LICENSE("GPL v2");
Linux with added FPC-III support