tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2014 Uwe Kleine-Koenig for Pengutronix
4 */
5#include <linux/module.h>
6#include <linux/platform_device.h>
7#include <linux/i2c.h>
8#include <linux/io.h>
9#include <linux/interrupt.h>
10#include <linux/err.h>
11#include <linux/clk.h>
12
13#define DRIVER_NAME "efm32-i2c"
14
15#define MASK_VAL(mask, val) ((val << __ffs(mask)) & mask)
16
17#define REG_CTRL 0x00
18#define REG_CTRL_EN 0x00001
19#define REG_CTRL_SLAVE 0x00002
20#define REG_CTRL_AUTOACK 0x00004
21#define REG_CTRL_AUTOSE 0x00008
22#define REG_CTRL_AUTOSN 0x00010
23#define REG_CTRL_ARBDIS 0x00020
24#define REG_CTRL_GCAMEN 0x00040
25#define REG_CTRL_CLHR__MASK 0x00300
26#define REG_CTRL_BITO__MASK 0x03000
27#define REG_CTRL_BITO_OFF 0x00000
28#define REG_CTRL_BITO_40PCC 0x01000
29#define REG_CTRL_BITO_80PCC 0x02000
30#define REG_CTRL_BITO_160PCC 0x03000
31#define REG_CTRL_GIBITO 0x08000
32#define REG_CTRL_CLTO__MASK 0x70000
33#define REG_CTRL_CLTO_OFF 0x00000
34
35#define REG_CMD 0x04
36#define REG_CMD_START 0x00001
37#define REG_CMD_STOP 0x00002
38#define REG_CMD_ACK 0x00004
39#define REG_CMD_NACK 0x00008
40#define REG_CMD_CONT 0x00010
41#define REG_CMD_ABORT 0x00020
42#define REG_CMD_CLEARTX 0x00040
43#define REG_CMD_CLEARPC 0x00080
44
45#define REG_STATE 0x08
46#define REG_STATE_BUSY 0x00001
47#define REG_STATE_MASTER 0x00002
48#define REG_STATE_TRANSMITTER 0x00004
49#define REG_STATE_NACKED 0x00008
50#define REG_STATE_BUSHOLD 0x00010
51#define REG_STATE_STATE__MASK 0x000e0
52#define REG_STATE_STATE_IDLE 0x00000
53#define REG_STATE_STATE_WAIT 0x00020
54#define REG_STATE_STATE_START 0x00040
55#define REG_STATE_STATE_ADDR 0x00060
56#define REG_STATE_STATE_ADDRACK 0x00080
57#define REG_STATE_STATE_DATA 0x000a0
58#define REG_STATE_STATE_DATAACK 0x000c0
59
60#define REG_STATUS 0x0c
61#define REG_STATUS_PSTART 0x00001
62#define REG_STATUS_PSTOP 0x00002
63#define REG_STATUS_PACK 0x00004
64#define REG_STATUS_PNACK 0x00008
65#define REG_STATUS_PCONT 0x00010
66#define REG_STATUS_PABORT 0x00020
67#define REG_STATUS_TXC 0x00040
68#define REG_STATUS_TXBL 0x00080
69#define REG_STATUS_RXDATAV 0x00100
70
71#define REG_CLKDIV 0x10
72#define REG_CLKDIV_DIV__MASK 0x001ff
73#define REG_CLKDIV_DIV(div) MASK_VAL(REG_CLKDIV_DIV__MASK, (div))
74
75#define REG_SADDR 0x14
76#define REG_SADDRMASK 0x18
77#define REG_RXDATA 0x1c
78#define REG_RXDATAP 0x20
79#define REG_TXDATA 0x24
80#define REG_IF 0x28
81#define REG_IF_START 0x00001
82#define REG_IF_RSTART 0x00002
83#define REG_IF_ADDR 0x00004
84#define REG_IF_TXC 0x00008
85#define REG_IF_TXBL 0x00010
86#define REG_IF_RXDATAV 0x00020
87#define REG_IF_ACK 0x00040
88#define REG_IF_NACK 0x00080
89#define REG_IF_MSTOP 0x00100
90#define REG_IF_ARBLOST 0x00200
91#define REG_IF_BUSERR 0x00400
92#define REG_IF_BUSHOLD 0x00800
93#define REG_IF_TXOF 0x01000
94#define REG_IF_RXUF 0x02000
95#define REG_IF_BITO 0x04000
96#define REG_IF_CLTO 0x08000
97#define REG_IF_SSTOP 0x10000
98
99#define REG_IFS 0x2c
100#define REG_IFC 0x30
101#define REG_IFC__MASK 0x1ffcf
102
103#define REG_IEN 0x34
104
105#define REG_ROUTE 0x38
106#define REG_ROUTE_SDAPEN 0x00001
107#define REG_ROUTE_SCLPEN 0x00002
108#define REG_ROUTE_LOCATION__MASK 0x00700
109#define REG_ROUTE_LOCATION(n) MASK_VAL(REG_ROUTE_LOCATION__MASK, (n))
110
111struct efm32_i2c_ddata {
112 struct i2c_adapter adapter;
113
114 struct clk *clk;
115 void __iomem *base;
116 unsigned int irq;
117 u8 location;
118 unsigned long frequency;
119
120 /* transfer data */
121 struct completion done;
122 struct i2c_msg *msgs;
123 size_t num_msgs;
124 size_t current_word, current_msg;
125 int retval;
126};
127
128static u32 efm32_i2c_read32(struct efm32_i2c_ddata *ddata, unsigned offset)
129{
130 return readl(ddata->base + offset);
131}
132
133static void efm32_i2c_write32(struct efm32_i2c_ddata *ddata,
134 unsigned offset, u32 value)
135{
136 writel(value, ddata->base + offset);
137}
138
139static void efm32_i2c_send_next_msg(struct efm32_i2c_ddata *ddata)
140{
141 struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
142
143 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_START);
144 efm32_i2c_write32(ddata, REG_TXDATA, i2c_8bit_addr_from_msg(cur_msg));
145}
146
147static void efm32_i2c_send_next_byte(struct efm32_i2c_ddata *ddata)
148{
149 struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
150
151 if (ddata->current_word >= cur_msg->len) {
152 /* cur_msg completely transferred */
153 ddata->current_word = 0;
154 ddata->current_msg += 1;
155
156 if (ddata->current_msg >= ddata->num_msgs) {
157 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
158 complete(&ddata->done);
159 } else {
160 efm32_i2c_send_next_msg(ddata);
161 }
162 } else {
163 efm32_i2c_write32(ddata, REG_TXDATA,
164 cur_msg->buf[ddata->current_word++]);
165 }
166}
167
168static void efm32_i2c_recv_next_byte(struct efm32_i2c_ddata *ddata)
169{
170 struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
171
172 cur_msg->buf[ddata->current_word] = efm32_i2c_read32(ddata, REG_RXDATA);
173 ddata->current_word += 1;
174 if (ddata->current_word >= cur_msg->len) {
175 /* cur_msg completely transferred */
176 ddata->current_word = 0;
177 ddata->current_msg += 1;
178
179 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_NACK);
180
181 if (ddata->current_msg >= ddata->num_msgs) {
182 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
183 complete(&ddata->done);
184 } else {
185 efm32_i2c_send_next_msg(ddata);
186 }
187 } else {
188 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ACK);
189 }
190}
191
192static irqreturn_t efm32_i2c_irq(int irq, void *dev_id)
193{
194 struct efm32_i2c_ddata *ddata = dev_id;
195 struct i2c_msg *cur_msg = &ddata->msgs[ddata->current_msg];
196 u32 irqflag = efm32_i2c_read32(ddata, REG_IF);
197 u32 state = efm32_i2c_read32(ddata, REG_STATE);
198
199 efm32_i2c_write32(ddata, REG_IFC, irqflag & REG_IFC__MASK);
200
201 switch (state & REG_STATE_STATE__MASK) {
202 case REG_STATE_STATE_IDLE:
203 /* arbitration lost? */
204 ddata->retval = -EAGAIN;
205 complete(&ddata->done);
206 break;
207 case REG_STATE_STATE_WAIT:
208 /*
209 * huh, this shouldn't happen.
210 * Reset hardware state and get out
211 */
212 ddata->retval = -EIO;
213 efm32_i2c_write32(ddata, REG_CMD,
214 REG_CMD_STOP | REG_CMD_ABORT |
215 REG_CMD_CLEARTX | REG_CMD_CLEARPC);
216 complete(&ddata->done);
217 break;
218 case REG_STATE_STATE_START:
219 /* "caller" is expected to send an address */
220 break;
221 case REG_STATE_STATE_ADDR:
222 /* wait for Ack or NAck of slave */
223 break;
224 case REG_STATE_STATE_ADDRACK:
225 if (state & REG_STATE_NACKED) {
226 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
227 ddata->retval = -ENXIO;
228 complete(&ddata->done);
229 } else if (cur_msg->flags & I2C_M_RD) {
230 /* wait for slave to send first data byte */
231 } else {
232 efm32_i2c_send_next_byte(ddata);
233 }
234 break;
235 case REG_STATE_STATE_DATA:
236 if (cur_msg->flags & I2C_M_RD) {
237 efm32_i2c_recv_next_byte(ddata);
238 } else {
239 /* wait for Ack or Nack of slave */
240 }
241 break;
242 case REG_STATE_STATE_DATAACK:
243 if (state & REG_STATE_NACKED) {
244 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_STOP);
245 complete(&ddata->done);
246 } else {
247 efm32_i2c_send_next_byte(ddata);
248 }
249 }
250
251 return IRQ_HANDLED;
252}
253
254static int efm32_i2c_master_xfer(struct i2c_adapter *adap,
255 struct i2c_msg *msgs, int num)
256{
257 struct efm32_i2c_ddata *ddata = i2c_get_adapdata(adap);
258 int ret;
259
260 if (ddata->msgs)
261 return -EBUSY;
262
263 ddata->msgs = msgs;
264 ddata->num_msgs = num;
265 ddata->current_word = 0;
266 ddata->current_msg = 0;
267 ddata->retval = -EIO;
268
269 reinit_completion(&ddata->done);
270
271 dev_dbg(&ddata->adapter.dev, "state: %08x, status: %08x\n",
272 efm32_i2c_read32(ddata, REG_STATE),
273 efm32_i2c_read32(ddata, REG_STATUS));
274
275 efm32_i2c_send_next_msg(ddata);
276
277 wait_for_completion(&ddata->done);
278
279 if (ddata->current_msg >= ddata->num_msgs)
280 ret = ddata->num_msgs;
281 else
282 ret = ddata->retval;
283
284 return ret;
285}
286
287static u32 efm32_i2c_functionality(struct i2c_adapter *adap)
288{
289 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
290}
291
292static const struct i2c_algorithm efm32_i2c_algo = {
293 .master_xfer = efm32_i2c_master_xfer,
294 .functionality = efm32_i2c_functionality,
295};
296
297static u32 efm32_i2c_get_configured_location(struct efm32_i2c_ddata *ddata)
298{
299 u32 reg = efm32_i2c_read32(ddata, REG_ROUTE);
300
301 return (reg & REG_ROUTE_LOCATION__MASK) >>
302 __ffs(REG_ROUTE_LOCATION__MASK);
303}
304
305static int efm32_i2c_probe(struct platform_device *pdev)
306{
307 struct efm32_i2c_ddata *ddata;
308 struct resource *res;
309 unsigned long rate;
310 struct device_node *np = pdev->dev.of_node;
311 u32 location, frequency;
312 int ret;
313 u32 clkdiv;
314
315 ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
316 if (!ddata)
317 return -ENOMEM;
318 platform_set_drvdata(pdev, ddata);
319
320 init_completion(&ddata->done);
321 strlcpy(ddata->adapter.name, pdev->name, sizeof(ddata->adapter.name));
322 ddata->adapter.owner = THIS_MODULE;
323 ddata->adapter.algo = &efm32_i2c_algo;
324 ddata->adapter.dev.parent = &pdev->dev;
325 ddata->adapter.dev.of_node = pdev->dev.of_node;
326 i2c_set_adapdata(&ddata->adapter, ddata);
327
328 ddata->clk = devm_clk_get(&pdev->dev, NULL);
329 if (IS_ERR(ddata->clk)) {
330 ret = PTR_ERR(ddata->clk);
331 dev_err(&pdev->dev, "failed to get clock: %d\n", ret);
332 return ret;
333 }
334
335 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
336 if (!res) {
337 dev_err(&pdev->dev, "failed to determine base address\n");
338 return -ENODEV;
339 }
340
341 if (resource_size(res) < 0x42) {
342 dev_err(&pdev->dev, "memory resource too small\n");
343 return -EINVAL;
344 }
345
346 ddata->base = devm_ioremap_resource(&pdev->dev, res);
347 if (IS_ERR(ddata->base))
348 return PTR_ERR(ddata->base);
349
350 ret = platform_get_irq(pdev, 0);
351 if (ret <= 0) {
352 if (!ret)
353 ret = -EINVAL;
354 return ret;
355 }
356
357 ddata->irq = ret;
358
359 ret = clk_prepare_enable(ddata->clk);
360 if (ret < 0) {
361 dev_err(&pdev->dev, "failed to enable clock (%d)\n", ret);
362 return ret;
363 }
364
365
366 ret = of_property_read_u32(np, "energymicro,location", &location);
367
368 if (ret)
369 /* fall back to wrongly namespaced property */
370 ret = of_property_read_u32(np, "efm32,location", &location);
371
372 if (!ret) {
373 dev_dbg(&pdev->dev, "using location %u\n", location);
374 } else {
375 /* default to location configured in hardware */
376 location = efm32_i2c_get_configured_location(ddata);
377
378 dev_info(&pdev->dev, "fall back to location %u\n", location);
379 }
380
381 ddata->location = location;
382
383 ret = of_property_read_u32(np, "clock-frequency", &frequency);
384 if (!ret) {
385 dev_dbg(&pdev->dev, "using frequency %u\n", frequency);
386 } else {
387 frequency = I2C_MAX_STANDARD_MODE_FREQ;
388 dev_info(&pdev->dev, "defaulting to 100 kHz\n");
389 }
390 ddata->frequency = frequency;
391
392 rate = clk_get_rate(ddata->clk);
393 if (!rate) {
394 dev_err(&pdev->dev, "there is no input clock available\n");
395 ret = -EINVAL;
396 goto err_disable_clk;
397 }
398 clkdiv = DIV_ROUND_UP(rate, 8 * ddata->frequency) - 1;
399 if (clkdiv >= 0x200) {
400 dev_err(&pdev->dev,
401 "input clock too fast (%lu) to divide down to bus freq (%lu)",
402 rate, ddata->frequency);
403 ret = -EINVAL;
404 goto err_disable_clk;
405 }
406
407 dev_dbg(&pdev->dev, "input clock = %lu, bus freq = %lu, clkdiv = %lu\n",
408 rate, ddata->frequency, (unsigned long)clkdiv);
409 efm32_i2c_write32(ddata, REG_CLKDIV, REG_CLKDIV_DIV(clkdiv));
410
411 efm32_i2c_write32(ddata, REG_ROUTE, REG_ROUTE_SDAPEN |
412 REG_ROUTE_SCLPEN |
413 REG_ROUTE_LOCATION(ddata->location));
414
415 efm32_i2c_write32(ddata, REG_CTRL, REG_CTRL_EN |
416 REG_CTRL_BITO_160PCC | 0 * REG_CTRL_GIBITO);
417
418 efm32_i2c_write32(ddata, REG_IFC, REG_IFC__MASK);
419 efm32_i2c_write32(ddata, REG_IEN, REG_IF_TXC | REG_IF_ACK | REG_IF_NACK
420 | REG_IF_ARBLOST | REG_IF_BUSERR | REG_IF_RXDATAV);
421
422 /* to make bus idle */
423 efm32_i2c_write32(ddata, REG_CMD, REG_CMD_ABORT);
424
425 ret = request_irq(ddata->irq, efm32_i2c_irq, 0, DRIVER_NAME, ddata);
426 if (ret < 0) {
427 dev_err(&pdev->dev, "failed to request irq (%d)\n", ret);
428 goto err_disable_clk;
429 }
430
431 ret = i2c_add_adapter(&ddata->adapter);
432 if (ret) {
433 free_irq(ddata->irq, ddata);
434
435err_disable_clk:
436 clk_disable_unprepare(ddata->clk);
437 }
438 return ret;
439}
440
441static int efm32_i2c_remove(struct platform_device *pdev)
442{
443 struct efm32_i2c_ddata *ddata = platform_get_drvdata(pdev);
444
445 i2c_del_adapter(&ddata->adapter);
446 free_irq(ddata->irq, ddata);
447 clk_disable_unprepare(ddata->clk);
448
449 return 0;
450}
451
452static const struct of_device_id efm32_i2c_dt_ids[] = {
453 {
454 .compatible = "energymicro,efm32-i2c",
455 }, {
456 /* sentinel */
457 }
458};
459MODULE_DEVICE_TABLE(of, efm32_i2c_dt_ids);
460
461static struct platform_driver efm32_i2c_driver = {
462 .probe = efm32_i2c_probe,
463 .remove = efm32_i2c_remove,
464
465 .driver = {
466 .name = DRIVER_NAME,
467 .of_match_table = efm32_i2c_dt_ids,
468 },
469};
470module_platform_driver(efm32_i2c_driver);
471
472MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
473MODULE_DESCRIPTION("EFM32 i2c driver");
474MODULE_LICENSE("GPL v2");
475MODULE_ALIAS("platform:" DRIVER_NAME);