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e6e5dd35 RJ |
1 | /* |
2 | * Copyright (C) 2014 Broadcom Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License as | |
6 | * published by the Free Software Foundation version 2. | |
7 | * | |
8 | * This program is distributed "as is" WITHOUT ANY WARRANTY of any | |
9 | * kind, whether express or implied; without even the implied warranty | |
10 | * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | */ | |
13 | ||
14 | #include <linux/delay.h> | |
15 | #include <linux/i2c.h> | |
16 | #include <linux/interrupt.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/platform_device.h> | |
21 | #include <linux/slab.h> | |
22 | ||
23 | #define CFG_OFFSET 0x00 | |
24 | #define CFG_RESET_SHIFT 31 | |
25 | #define CFG_EN_SHIFT 30 | |
26 | #define CFG_M_RETRY_CNT_SHIFT 16 | |
27 | #define CFG_M_RETRY_CNT_MASK 0x0f | |
28 | ||
29 | #define TIM_CFG_OFFSET 0x04 | |
30 | #define TIM_CFG_MODE_400_SHIFT 31 | |
31 | ||
32 | #define M_FIFO_CTRL_OFFSET 0x0c | |
33 | #define M_FIFO_RX_FLUSH_SHIFT 31 | |
34 | #define M_FIFO_TX_FLUSH_SHIFT 30 | |
35 | #define M_FIFO_RX_CNT_SHIFT 16 | |
36 | #define M_FIFO_RX_CNT_MASK 0x7f | |
37 | #define M_FIFO_RX_THLD_SHIFT 8 | |
38 | #define M_FIFO_RX_THLD_MASK 0x3f | |
39 | ||
40 | #define M_CMD_OFFSET 0x30 | |
41 | #define M_CMD_START_BUSY_SHIFT 31 | |
42 | #define M_CMD_STATUS_SHIFT 25 | |
43 | #define M_CMD_STATUS_MASK 0x07 | |
44 | #define M_CMD_STATUS_SUCCESS 0x0 | |
45 | #define M_CMD_STATUS_LOST_ARB 0x1 | |
46 | #define M_CMD_STATUS_NACK_ADDR 0x2 | |
47 | #define M_CMD_STATUS_NACK_DATA 0x3 | |
48 | #define M_CMD_STATUS_TIMEOUT 0x4 | |
49 | #define M_CMD_PROTOCOL_SHIFT 9 | |
50 | #define M_CMD_PROTOCOL_MASK 0xf | |
51 | #define M_CMD_PROTOCOL_BLK_WR 0x7 | |
52 | #define M_CMD_PROTOCOL_BLK_RD 0x8 | |
53 | #define M_CMD_PEC_SHIFT 8 | |
54 | #define M_CMD_RD_CNT_SHIFT 0 | |
55 | #define M_CMD_RD_CNT_MASK 0xff | |
56 | ||
57 | #define IE_OFFSET 0x38 | |
58 | #define IE_M_RX_FIFO_FULL_SHIFT 31 | |
59 | #define IE_M_RX_THLD_SHIFT 30 | |
60 | #define IE_M_START_BUSY_SHIFT 28 | |
61 | ||
62 | #define IS_OFFSET 0x3c | |
63 | #define IS_M_RX_FIFO_FULL_SHIFT 31 | |
64 | #define IS_M_RX_THLD_SHIFT 30 | |
65 | #define IS_M_START_BUSY_SHIFT 28 | |
66 | ||
67 | #define M_TX_OFFSET 0x40 | |
68 | #define M_TX_WR_STATUS_SHIFT 31 | |
69 | #define M_TX_DATA_SHIFT 0 | |
70 | #define M_TX_DATA_MASK 0xff | |
71 | ||
72 | #define M_RX_OFFSET 0x44 | |
73 | #define M_RX_STATUS_SHIFT 30 | |
74 | #define M_RX_STATUS_MASK 0x03 | |
75 | #define M_RX_PEC_ERR_SHIFT 29 | |
76 | #define M_RX_DATA_SHIFT 0 | |
77 | #define M_RX_DATA_MASK 0xff | |
78 | ||
79 | #define I2C_TIMEOUT_MESC 100 | |
80 | #define M_TX_RX_FIFO_SIZE 64 | |
81 | ||
82 | enum bus_speed_index { | |
83 | I2C_SPD_100K = 0, | |
84 | I2C_SPD_400K, | |
85 | }; | |
86 | ||
87 | struct bcm_iproc_i2c_dev { | |
88 | struct device *device; | |
89 | int irq; | |
90 | ||
91 | void __iomem *base; | |
92 | ||
93 | struct i2c_adapter adapter; | |
94 | ||
95 | struct completion done; | |
96 | int xfer_is_done; | |
97 | }; | |
98 | ||
99 | /* | |
100 | * Can be expanded in the future if more interrupt status bits are utilized | |
101 | */ | |
102 | #define ISR_MASK (1 << IS_M_START_BUSY_SHIFT) | |
103 | ||
104 | static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) | |
105 | { | |
106 | struct bcm_iproc_i2c_dev *iproc_i2c = data; | |
107 | u32 status = readl(iproc_i2c->base + IS_OFFSET); | |
108 | ||
109 | status &= ISR_MASK; | |
110 | ||
111 | if (!status) | |
112 | return IRQ_NONE; | |
113 | ||
114 | writel(status, iproc_i2c->base + IS_OFFSET); | |
115 | iproc_i2c->xfer_is_done = 1; | |
116 | complete_all(&iproc_i2c->done); | |
117 | ||
118 | return IRQ_HANDLED; | |
119 | } | |
120 | ||
121 | static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *iproc_i2c, | |
122 | struct i2c_msg *msg) | |
123 | { | |
124 | u32 val; | |
125 | ||
126 | val = readl(iproc_i2c->base + M_CMD_OFFSET); | |
127 | val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK; | |
128 | ||
129 | switch (val) { | |
130 | case M_CMD_STATUS_SUCCESS: | |
131 | return 0; | |
132 | ||
133 | case M_CMD_STATUS_LOST_ARB: | |
134 | dev_dbg(iproc_i2c->device, "lost bus arbitration\n"); | |
135 | return -EAGAIN; | |
136 | ||
137 | case M_CMD_STATUS_NACK_ADDR: | |
138 | dev_dbg(iproc_i2c->device, "NAK addr:0x%02x\n", msg->addr); | |
139 | return -ENXIO; | |
140 | ||
141 | case M_CMD_STATUS_NACK_DATA: | |
142 | dev_dbg(iproc_i2c->device, "NAK data\n"); | |
143 | return -ENXIO; | |
144 | ||
145 | case M_CMD_STATUS_TIMEOUT: | |
146 | dev_dbg(iproc_i2c->device, "bus timeout\n"); | |
147 | return -ETIMEDOUT; | |
148 | ||
149 | default: | |
150 | dev_dbg(iproc_i2c->device, "unknown error code=%d\n", val); | |
151 | return -EIO; | |
152 | } | |
153 | } | |
154 | ||
155 | static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, | |
156 | struct i2c_msg *msg) | |
157 | { | |
158 | int ret, i; | |
159 | u8 addr; | |
160 | u32 val; | |
161 | unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MESC); | |
162 | ||
163 | /* need to reserve one byte in the FIFO for the slave address */ | |
164 | if (msg->len > M_TX_RX_FIFO_SIZE - 1) { | |
165 | dev_err(iproc_i2c->device, | |
166 | "only support data length up to %u bytes\n", | |
167 | M_TX_RX_FIFO_SIZE - 1); | |
168 | return -EOPNOTSUPP; | |
169 | } | |
170 | ||
171 | /* check if bus is busy */ | |
172 | if (!!(readl(iproc_i2c->base + M_CMD_OFFSET) & | |
173 | BIT(M_CMD_START_BUSY_SHIFT))) { | |
174 | dev_warn(iproc_i2c->device, "bus is busy\n"); | |
175 | return -EBUSY; | |
176 | } | |
177 | ||
178 | /* format and load slave address into the TX FIFO */ | |
179 | addr = msg->addr << 1 | (msg->flags & I2C_M_RD ? 1 : 0); | |
180 | writel(addr, iproc_i2c->base + M_TX_OFFSET); | |
181 | ||
182 | /* for a write transaction, load data into the TX FIFO */ | |
183 | if (!(msg->flags & I2C_M_RD)) { | |
184 | for (i = 0; i < msg->len; i++) { | |
185 | val = msg->buf[i]; | |
186 | ||
187 | /* mark the last byte */ | |
188 | if (i == msg->len - 1) | |
189 | val |= 1 << M_TX_WR_STATUS_SHIFT; | |
190 | ||
191 | writel(val, iproc_i2c->base + M_TX_OFFSET); | |
192 | } | |
193 | } | |
194 | ||
195 | /* mark as incomplete before starting the transaction */ | |
196 | reinit_completion(&iproc_i2c->done); | |
197 | iproc_i2c->xfer_is_done = 0; | |
198 | ||
199 | /* | |
200 | * Enable the "start busy" interrupt, which will be triggered after the | |
201 | * transaction is done, i.e., the internal start_busy bit, transitions | |
202 | * from 1 to 0. | |
203 | */ | |
204 | writel(1 << IE_M_START_BUSY_SHIFT, iproc_i2c->base + IE_OFFSET); | |
205 | ||
206 | /* | |
207 | * Now we can activate the transfer. For a read operation, specify the | |
208 | * number of bytes to read | |
209 | */ | |
210 | val = 1 << M_CMD_START_BUSY_SHIFT; | |
211 | if (msg->flags & I2C_M_RD) { | |
212 | val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | | |
213 | (msg->len << M_CMD_RD_CNT_SHIFT); | |
214 | } else { | |
215 | val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT); | |
216 | } | |
217 | writel(val, iproc_i2c->base + M_CMD_OFFSET); | |
218 | ||
219 | time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left); | |
220 | ||
221 | /* disable all interrupts */ | |
222 | writel(0, iproc_i2c->base + IE_OFFSET); | |
223 | /* read it back to flush the write */ | |
224 | readl(iproc_i2c->base + IE_OFFSET); | |
225 | ||
226 | /* make sure the interrupt handler isn't running */ | |
227 | synchronize_irq(iproc_i2c->irq); | |
228 | ||
229 | if (!time_left && !iproc_i2c->xfer_is_done) { | |
230 | dev_err(iproc_i2c->device, "transaction timed out\n"); | |
231 | ||
232 | /* flush FIFOs */ | |
233 | val = (1 << M_FIFO_RX_FLUSH_SHIFT) | | |
234 | (1 << M_FIFO_TX_FLUSH_SHIFT); | |
235 | writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET); | |
236 | return -ETIMEDOUT; | |
237 | } | |
238 | ||
239 | ret = bcm_iproc_i2c_check_status(iproc_i2c, msg); | |
240 | if (ret) { | |
241 | /* flush both TX/RX FIFOs */ | |
242 | val = (1 << M_FIFO_RX_FLUSH_SHIFT) | | |
243 | (1 << M_FIFO_TX_FLUSH_SHIFT); | |
244 | writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET); | |
245 | return ret; | |
246 | } | |
247 | ||
248 | /* | |
249 | * For a read operation, we now need to load the data from FIFO | |
250 | * into the memory buffer | |
251 | */ | |
252 | if (msg->flags & I2C_M_RD) { | |
253 | for (i = 0; i < msg->len; i++) { | |
254 | msg->buf[i] = (readl(iproc_i2c->base + M_RX_OFFSET) >> | |
255 | M_RX_DATA_SHIFT) & M_RX_DATA_MASK; | |
256 | } | |
257 | } | |
258 | ||
259 | return 0; | |
260 | } | |
261 | ||
262 | static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter, | |
263 | struct i2c_msg msgs[], int num) | |
264 | { | |
265 | struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adapter); | |
266 | int ret, i; | |
267 | ||
268 | /* go through all messages */ | |
269 | for (i = 0; i < num; i++) { | |
270 | ret = bcm_iproc_i2c_xfer_single_msg(iproc_i2c, &msgs[i]); | |
271 | if (ret) { | |
272 | dev_dbg(iproc_i2c->device, "xfer failed\n"); | |
273 | return ret; | |
274 | } | |
275 | } | |
276 | ||
277 | return num; | |
278 | } | |
279 | ||
280 | static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap) | |
281 | { | |
282 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; | |
283 | } | |
284 | ||
285 | static const struct i2c_algorithm bcm_iproc_algo = { | |
286 | .master_xfer = bcm_iproc_i2c_xfer, | |
287 | .functionality = bcm_iproc_i2c_functionality, | |
288 | }; | |
289 | ||
290 | static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c) | |
291 | { | |
292 | unsigned int bus_speed; | |
293 | u32 val; | |
294 | int ret = of_property_read_u32(iproc_i2c->device->of_node, | |
295 | "clock-frequency", &bus_speed); | |
296 | if (ret < 0) { | |
297 | dev_info(iproc_i2c->device, | |
298 | "unable to interpret clock-frequency DT property\n"); | |
299 | bus_speed = 100000; | |
300 | } | |
301 | ||
302 | if (bus_speed < 100000) { | |
303 | dev_err(iproc_i2c->device, "%d Hz bus speed not supported\n", | |
304 | bus_speed); | |
305 | dev_err(iproc_i2c->device, | |
306 | "valid speeds are 100khz and 400khz\n"); | |
307 | return -EINVAL; | |
308 | } else if (bus_speed < 400000) { | |
309 | bus_speed = 100000; | |
310 | } else { | |
311 | bus_speed = 400000; | |
312 | } | |
313 | ||
314 | val = readl(iproc_i2c->base + TIM_CFG_OFFSET); | |
315 | val &= ~(1 << TIM_CFG_MODE_400_SHIFT); | |
316 | val |= (bus_speed == 400000) << TIM_CFG_MODE_400_SHIFT; | |
317 | writel(val, iproc_i2c->base + TIM_CFG_OFFSET); | |
318 | ||
319 | dev_info(iproc_i2c->device, "bus set to %u Hz\n", bus_speed); | |
320 | ||
321 | return 0; | |
322 | } | |
323 | ||
324 | static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *iproc_i2c) | |
325 | { | |
326 | u32 val; | |
327 | ||
328 | /* put controller in reset */ | |
329 | val = readl(iproc_i2c->base + CFG_OFFSET); | |
330 | val |= 1 << CFG_RESET_SHIFT; | |
331 | val &= ~(1 << CFG_EN_SHIFT); | |
332 | writel(val, iproc_i2c->base + CFG_OFFSET); | |
333 | ||
334 | /* wait 100 usec per spec */ | |
335 | udelay(100); | |
336 | ||
337 | /* bring controller out of reset */ | |
338 | val &= ~(1 << CFG_RESET_SHIFT); | |
339 | writel(val, iproc_i2c->base + CFG_OFFSET); | |
340 | ||
341 | /* flush TX/RX FIFOs and set RX FIFO threshold to zero */ | |
342 | val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); | |
343 | writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET); | |
344 | ||
345 | /* disable all interrupts */ | |
346 | writel(0, iproc_i2c->base + IE_OFFSET); | |
347 | ||
348 | /* clear all pending interrupts */ | |
349 | writel(0xffffffff, iproc_i2c->base + IS_OFFSET); | |
350 | ||
351 | return 0; | |
352 | } | |
353 | ||
354 | static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c, | |
355 | bool enable) | |
356 | { | |
357 | u32 val; | |
358 | ||
359 | val = readl(iproc_i2c->base + CFG_OFFSET); | |
360 | if (enable) | |
361 | val |= BIT(CFG_EN_SHIFT); | |
362 | else | |
363 | val &= ~BIT(CFG_EN_SHIFT); | |
364 | writel(val, iproc_i2c->base + CFG_OFFSET); | |
365 | } | |
366 | ||
367 | static int bcm_iproc_i2c_probe(struct platform_device *pdev) | |
368 | { | |
369 | int irq, ret = 0; | |
370 | struct bcm_iproc_i2c_dev *iproc_i2c; | |
371 | struct i2c_adapter *adap; | |
372 | struct resource *res; | |
373 | ||
374 | iproc_i2c = devm_kzalloc(&pdev->dev, sizeof(*iproc_i2c), | |
375 | GFP_KERNEL); | |
376 | if (!iproc_i2c) | |
377 | return -ENOMEM; | |
378 | ||
379 | platform_set_drvdata(pdev, iproc_i2c); | |
380 | iproc_i2c->device = &pdev->dev; | |
381 | init_completion(&iproc_i2c->done); | |
382 | ||
383 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
384 | iproc_i2c->base = devm_ioremap_resource(iproc_i2c->device, res); | |
385 | if (IS_ERR(iproc_i2c->base)) | |
386 | return PTR_ERR(iproc_i2c->base); | |
387 | ||
388 | ret = bcm_iproc_i2c_init(iproc_i2c); | |
389 | if (ret) | |
390 | return ret; | |
391 | ||
392 | ret = bcm_iproc_i2c_cfg_speed(iproc_i2c); | |
393 | if (ret) | |
394 | return ret; | |
395 | ||
396 | irq = platform_get_irq(pdev, 0); | |
397 | if (irq <= 0) { | |
398 | dev_err(iproc_i2c->device, "no irq resource\n"); | |
399 | return irq; | |
400 | } | |
401 | iproc_i2c->irq = irq; | |
402 | ||
403 | ret = devm_request_irq(iproc_i2c->device, irq, bcm_iproc_i2c_isr, 0, | |
404 | pdev->name, iproc_i2c); | |
405 | if (ret < 0) { | |
406 | dev_err(iproc_i2c->device, "unable to request irq %i\n", irq); | |
407 | return ret; | |
408 | } | |
409 | ||
410 | bcm_iproc_i2c_enable_disable(iproc_i2c, true); | |
411 | ||
412 | adap = &iproc_i2c->adapter; | |
413 | i2c_set_adapdata(adap, iproc_i2c); | |
414 | strlcpy(adap->name, "Broadcom iProc I2C adapter", sizeof(adap->name)); | |
415 | adap->algo = &bcm_iproc_algo; | |
416 | adap->dev.parent = &pdev->dev; | |
417 | adap->dev.of_node = pdev->dev.of_node; | |
418 | ||
419 | ret = i2c_add_adapter(adap); | |
420 | if (ret) { | |
421 | dev_err(iproc_i2c->device, "failed to add adapter\n"); | |
422 | return ret; | |
423 | } | |
424 | ||
425 | return 0; | |
426 | } | |
427 | ||
428 | static int bcm_iproc_i2c_remove(struct platform_device *pdev) | |
429 | { | |
430 | struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev); | |
431 | ||
432 | /* make sure there's no pending interrupt when we remove the adapter */ | |
433 | writel(0, iproc_i2c->base + IE_OFFSET); | |
434 | readl(iproc_i2c->base + IE_OFFSET); | |
435 | synchronize_irq(iproc_i2c->irq); | |
436 | ||
437 | i2c_del_adapter(&iproc_i2c->adapter); | |
438 | bcm_iproc_i2c_enable_disable(iproc_i2c, false); | |
439 | ||
440 | return 0; | |
441 | } | |
442 | ||
443 | static const struct of_device_id bcm_iproc_i2c_of_match[] = { | |
444 | { .compatible = "brcm,iproc-i2c" }, | |
445 | { /* sentinel */ } | |
446 | }; | |
447 | MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match); | |
448 | ||
449 | static struct platform_driver bcm_iproc_i2c_driver = { | |
450 | .driver = { | |
451 | .name = "bcm-iproc-i2c", | |
452 | .of_match_table = bcm_iproc_i2c_of_match, | |
453 | }, | |
454 | .probe = bcm_iproc_i2c_probe, | |
455 | .remove = bcm_iproc_i2c_remove, | |
456 | }; | |
457 | module_platform_driver(bcm_iproc_i2c_driver); | |
458 | ||
459 | MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>"); | |
460 | MODULE_DESCRIPTION("Broadcom iProc I2C Driver"); | |
461 | MODULE_LICENSE("GPL v2"); |