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a8da7fec WS |
1 | /* |
2 | * Freescale MXS I2C bus driver | |
3 | * | |
4 | * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K. | |
5 | * | |
6 | * based on a (non-working) driver which was: | |
7 | * | |
8 | * Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved. | |
9 | * | |
10 | * TODO: add dma-support if platform-support for it is available | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or | |
15 | * (at your option) any later version. | |
16 | * | |
17 | */ | |
18 | ||
19 | #include <linux/slab.h> | |
20 | #include <linux/device.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/i2c.h> | |
23 | #include <linux/err.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/completion.h> | |
26 | #include <linux/platform_device.h> | |
27 | #include <linux/jiffies.h> | |
28 | #include <linux/io.h> | |
29 | ||
30 | #include <mach/common.h> | |
31 | ||
32 | #define DRIVER_NAME "mxs-i2c" | |
33 | ||
34 | #define MXS_I2C_CTRL0 (0x00) | |
35 | #define MXS_I2C_CTRL0_SET (0x04) | |
36 | ||
37 | #define MXS_I2C_CTRL0_SFTRST 0x80000000 | |
38 | #define MXS_I2C_CTRL0_SEND_NAK_ON_LAST 0x02000000 | |
39 | #define MXS_I2C_CTRL0_RETAIN_CLOCK 0x00200000 | |
40 | #define MXS_I2C_CTRL0_POST_SEND_STOP 0x00100000 | |
41 | #define MXS_I2C_CTRL0_PRE_SEND_START 0x00080000 | |
42 | #define MXS_I2C_CTRL0_MASTER_MODE 0x00020000 | |
43 | #define MXS_I2C_CTRL0_DIRECTION 0x00010000 | |
44 | #define MXS_I2C_CTRL0_XFER_COUNT(v) ((v) & 0x0000FFFF) | |
45 | ||
46 | #define MXS_I2C_CTRL1 (0x40) | |
47 | #define MXS_I2C_CTRL1_SET (0x44) | |
48 | #define MXS_I2C_CTRL1_CLR (0x48) | |
49 | ||
50 | #define MXS_I2C_CTRL1_BUS_FREE_IRQ 0x80 | |
51 | #define MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ 0x40 | |
52 | #define MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ 0x20 | |
53 | #define MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ 0x10 | |
54 | #define MXS_I2C_CTRL1_EARLY_TERM_IRQ 0x08 | |
55 | #define MXS_I2C_CTRL1_MASTER_LOSS_IRQ 0x04 | |
56 | #define MXS_I2C_CTRL1_SLAVE_STOP_IRQ 0x02 | |
57 | #define MXS_I2C_CTRL1_SLAVE_IRQ 0x01 | |
58 | ||
59 | #define MXS_I2C_IRQ_MASK (MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | \ | |
60 | MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ | \ | |
61 | MXS_I2C_CTRL1_EARLY_TERM_IRQ | \ | |
62 | MXS_I2C_CTRL1_MASTER_LOSS_IRQ | \ | |
63 | MXS_I2C_CTRL1_SLAVE_STOP_IRQ | \ | |
64 | MXS_I2C_CTRL1_SLAVE_IRQ) | |
65 | ||
66 | #define MXS_I2C_QUEUECTRL (0x60) | |
67 | #define MXS_I2C_QUEUECTRL_SET (0x64) | |
68 | #define MXS_I2C_QUEUECTRL_CLR (0x68) | |
69 | ||
70 | #define MXS_I2C_QUEUECTRL_QUEUE_RUN 0x20 | |
71 | #define MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE 0x04 | |
72 | ||
73 | #define MXS_I2C_QUEUESTAT (0x70) | |
74 | #define MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY 0x00002000 | |
75 | ||
76 | #define MXS_I2C_QUEUECMD (0x80) | |
77 | ||
78 | #define MXS_I2C_QUEUEDATA (0x90) | |
79 | ||
80 | #define MXS_I2C_DATA (0xa0) | |
81 | ||
82 | ||
83 | #define MXS_CMD_I2C_SELECT (MXS_I2C_CTRL0_RETAIN_CLOCK | \ | |
84 | MXS_I2C_CTRL0_PRE_SEND_START | \ | |
85 | MXS_I2C_CTRL0_MASTER_MODE | \ | |
86 | MXS_I2C_CTRL0_DIRECTION | \ | |
87 | MXS_I2C_CTRL0_XFER_COUNT(1)) | |
88 | ||
89 | #define MXS_CMD_I2C_WRITE (MXS_I2C_CTRL0_PRE_SEND_START | \ | |
90 | MXS_I2C_CTRL0_MASTER_MODE | \ | |
91 | MXS_I2C_CTRL0_DIRECTION) | |
92 | ||
93 | #define MXS_CMD_I2C_READ (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \ | |
94 | MXS_I2C_CTRL0_MASTER_MODE) | |
95 | ||
96 | /** | |
97 | * struct mxs_i2c_dev - per device, private MXS-I2C data | |
98 | * | |
99 | * @dev: driver model device node | |
100 | * @regs: IO registers pointer | |
101 | * @cmd_complete: completion object for transaction wait | |
102 | * @cmd_err: error code for last transaction | |
103 | * @adapter: i2c subsystem adapter node | |
104 | */ | |
105 | struct mxs_i2c_dev { | |
106 | struct device *dev; | |
107 | void __iomem *regs; | |
108 | struct completion cmd_complete; | |
109 | u32 cmd_err; | |
110 | struct i2c_adapter adapter; | |
111 | }; | |
112 | ||
113 | /* | |
114 | * TODO: check if calls to here are really needed. If not, we could get rid of | |
115 | * mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably. | |
116 | */ | |
117 | static void mxs_i2c_reset(struct mxs_i2c_dev *i2c) | |
118 | { | |
119 | mxs_reset_block(i2c->regs); | |
120 | writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET); | |
6b7d815c SH |
121 | writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE, |
122 | i2c->regs + MXS_I2C_QUEUECTRL_SET); | |
a8da7fec WS |
123 | } |
124 | ||
125 | static void mxs_i2c_pioq_setup_read(struct mxs_i2c_dev *i2c, u8 addr, int len, | |
126 | int flags) | |
127 | { | |
128 | u32 data; | |
129 | ||
130 | writel(MXS_CMD_I2C_SELECT, i2c->regs + MXS_I2C_QUEUECMD); | |
131 | ||
132 | data = (addr << 1) | I2C_SMBUS_READ; | |
133 | writel(data, i2c->regs + MXS_I2C_DATA); | |
134 | ||
135 | data = MXS_CMD_I2C_READ | MXS_I2C_CTRL0_XFER_COUNT(len) | flags; | |
136 | writel(data, i2c->regs + MXS_I2C_QUEUECMD); | |
137 | } | |
138 | ||
139 | static void mxs_i2c_pioq_setup_write(struct mxs_i2c_dev *i2c, | |
140 | u8 addr, u8 *buf, int len, int flags) | |
141 | { | |
142 | u32 data; | |
143 | int i, shifts_left; | |
144 | ||
145 | data = MXS_CMD_I2C_WRITE | MXS_I2C_CTRL0_XFER_COUNT(len + 1) | flags; | |
146 | writel(data, i2c->regs + MXS_I2C_QUEUECMD); | |
147 | ||
148 | /* | |
149 | * We have to copy the slave address (u8) and buffer (arbitrary number | |
150 | * of u8) into the data register (u32). To achieve that, the u8 are put | |
151 | * into the MSBs of 'data' which is then shifted for the next u8. When | |
25985edc | 152 | * appropriate, 'data' is written to MXS_I2C_DATA. So, the first u32 |
a8da7fec WS |
153 | * looks like this: |
154 | * | |
155 | * 3 2 1 0 | |
156 | * 10987654|32109876|54321098|76543210 | |
157 | * --------+--------+--------+-------- | |
158 | * buffer+2|buffer+1|buffer+0|slave_addr | |
159 | */ | |
160 | ||
161 | data = ((addr << 1) | I2C_SMBUS_WRITE) << 24; | |
162 | ||
163 | for (i = 0; i < len; i++) { | |
164 | data >>= 8; | |
165 | data |= buf[i] << 24; | |
166 | if ((i & 3) == 2) | |
167 | writel(data, i2c->regs + MXS_I2C_DATA); | |
168 | } | |
169 | ||
170 | /* Write out the remaining bytes if any */ | |
171 | shifts_left = 24 - (i & 3) * 8; | |
172 | if (shifts_left) | |
173 | writel(data >> shifts_left, i2c->regs + MXS_I2C_DATA); | |
174 | } | |
175 | ||
176 | /* | |
177 | * TODO: should be replaceable with a waitqueue and RD_QUEUE_IRQ (setting the | |
178 | * rd_threshold to 1). Couldn't get this to work, though. | |
179 | */ | |
180 | static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c) | |
181 | { | |
182 | unsigned long timeout = jiffies + msecs_to_jiffies(1000); | |
183 | ||
184 | while (readl(i2c->regs + MXS_I2C_QUEUESTAT) | |
185 | & MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY) { | |
186 | if (time_after(jiffies, timeout)) | |
187 | return -ETIMEDOUT; | |
188 | cond_resched(); | |
189 | } | |
190 | ||
191 | return 0; | |
192 | } | |
193 | ||
194 | static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len) | |
195 | { | |
196 | u32 data; | |
197 | int i; | |
198 | ||
199 | for (i = 0; i < len; i++) { | |
200 | if ((i & 3) == 0) { | |
201 | if (mxs_i2c_wait_for_data(i2c)) | |
202 | return -ETIMEDOUT; | |
203 | data = readl(i2c->regs + MXS_I2C_QUEUEDATA); | |
204 | } | |
205 | buf[i] = data & 0xff; | |
206 | data >>= 8; | |
207 | } | |
208 | ||
209 | return 0; | |
210 | } | |
211 | ||
212 | /* | |
213 | * Low level master read/write transaction. | |
214 | */ | |
215 | static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, | |
216 | int stop) | |
217 | { | |
218 | struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap); | |
219 | int ret; | |
220 | int flags; | |
221 | ||
222 | init_completion(&i2c->cmd_complete); | |
223 | ||
224 | dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n", | |
225 | msg->addr, msg->len, msg->flags, stop); | |
226 | ||
227 | if (msg->len == 0) | |
228 | return -EINVAL; | |
229 | ||
230 | flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0; | |
231 | ||
232 | if (msg->flags & I2C_M_RD) | |
233 | mxs_i2c_pioq_setup_read(i2c, msg->addr, msg->len, flags); | |
234 | else | |
235 | mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf, msg->len, | |
236 | flags); | |
237 | ||
238 | writel(MXS_I2C_QUEUECTRL_QUEUE_RUN, | |
239 | i2c->regs + MXS_I2C_QUEUECTRL_SET); | |
240 | ||
241 | ret = wait_for_completion_timeout(&i2c->cmd_complete, | |
242 | msecs_to_jiffies(1000)); | |
243 | if (ret == 0) | |
244 | goto timeout; | |
245 | ||
246 | if ((!i2c->cmd_err) && (msg->flags & I2C_M_RD)) { | |
247 | ret = mxs_i2c_finish_read(i2c, msg->buf, msg->len); | |
248 | if (ret) | |
249 | goto timeout; | |
250 | } | |
251 | ||
252 | if (i2c->cmd_err == -ENXIO) | |
253 | mxs_i2c_reset(i2c); | |
254 | ||
255 | dev_dbg(i2c->dev, "Done with err=%d\n", i2c->cmd_err); | |
256 | ||
257 | return i2c->cmd_err; | |
258 | ||
259 | timeout: | |
260 | dev_dbg(i2c->dev, "Timeout!\n"); | |
261 | mxs_i2c_reset(i2c); | |
262 | return -ETIMEDOUT; | |
263 | } | |
264 | ||
265 | static int mxs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], | |
266 | int num) | |
267 | { | |
268 | int i; | |
269 | int err; | |
270 | ||
271 | for (i = 0; i < num; i++) { | |
272 | err = mxs_i2c_xfer_msg(adap, &msgs[i], i == (num - 1)); | |
273 | if (err) | |
274 | return err; | |
275 | } | |
276 | ||
277 | return num; | |
278 | } | |
279 | ||
280 | static u32 mxs_i2c_func(struct i2c_adapter *adap) | |
281 | { | |
282 | return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); | |
283 | } | |
284 | ||
285 | static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id) | |
286 | { | |
287 | struct mxs_i2c_dev *i2c = dev_id; | |
288 | u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK; | |
289 | ||
290 | if (!stat) | |
291 | return IRQ_NONE; | |
292 | ||
293 | if (stat & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ) | |
294 | i2c->cmd_err = -ENXIO; | |
295 | else if (stat & (MXS_I2C_CTRL1_EARLY_TERM_IRQ | | |
296 | MXS_I2C_CTRL1_MASTER_LOSS_IRQ | | |
297 | MXS_I2C_CTRL1_SLAVE_STOP_IRQ | MXS_I2C_CTRL1_SLAVE_IRQ)) | |
298 | /* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */ | |
299 | i2c->cmd_err = -EIO; | |
300 | else | |
301 | i2c->cmd_err = 0; | |
302 | ||
303 | complete(&i2c->cmd_complete); | |
304 | ||
305 | writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR); | |
306 | return IRQ_HANDLED; | |
307 | } | |
308 | ||
309 | static const struct i2c_algorithm mxs_i2c_algo = { | |
310 | .master_xfer = mxs_i2c_xfer, | |
311 | .functionality = mxs_i2c_func, | |
312 | }; | |
313 | ||
314 | static int __devinit mxs_i2c_probe(struct platform_device *pdev) | |
315 | { | |
316 | struct device *dev = &pdev->dev; | |
317 | struct mxs_i2c_dev *i2c; | |
318 | struct i2c_adapter *adap; | |
319 | struct resource *res; | |
320 | resource_size_t res_size; | |
321 | int err, irq; | |
322 | ||
323 | i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL); | |
324 | if (!i2c) | |
325 | return -ENOMEM; | |
326 | ||
327 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
328 | if (!res) | |
329 | return -ENOENT; | |
330 | ||
331 | res_size = resource_size(res); | |
332 | if (!devm_request_mem_region(dev, res->start, res_size, res->name)) | |
333 | return -EBUSY; | |
334 | ||
335 | i2c->regs = devm_ioremap_nocache(dev, res->start, res_size); | |
336 | if (!i2c->regs) | |
337 | return -EBUSY; | |
338 | ||
339 | irq = platform_get_irq(pdev, 0); | |
340 | if (irq < 0) | |
341 | return irq; | |
342 | ||
343 | err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c); | |
344 | if (err) | |
345 | return err; | |
346 | ||
347 | i2c->dev = dev; | |
348 | platform_set_drvdata(pdev, i2c); | |
349 | ||
350 | /* Do reset to enforce correct startup after pinmuxing */ | |
351 | mxs_i2c_reset(i2c); | |
a8da7fec WS |
352 | |
353 | adap = &i2c->adapter; | |
354 | strlcpy(adap->name, "MXS I2C adapter", sizeof(adap->name)); | |
355 | adap->owner = THIS_MODULE; | |
356 | adap->algo = &mxs_i2c_algo; | |
357 | adap->dev.parent = dev; | |
358 | adap->nr = pdev->id; | |
359 | i2c_set_adapdata(adap, i2c); | |
360 | err = i2c_add_numbered_adapter(adap); | |
361 | if (err) { | |
362 | dev_err(dev, "Failed to add adapter (%d)\n", err); | |
363 | writel(MXS_I2C_CTRL0_SFTRST, | |
364 | i2c->regs + MXS_I2C_CTRL0_SET); | |
365 | return err; | |
366 | } | |
367 | ||
368 | return 0; | |
369 | } | |
370 | ||
371 | static int __devexit mxs_i2c_remove(struct platform_device *pdev) | |
372 | { | |
373 | struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev); | |
374 | int ret; | |
375 | ||
376 | ret = i2c_del_adapter(&i2c->adapter); | |
377 | if (ret) | |
378 | return -EBUSY; | |
379 | ||
380 | writel(MXS_I2C_QUEUECTRL_QUEUE_RUN, | |
381 | i2c->regs + MXS_I2C_QUEUECTRL_CLR); | |
382 | writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET); | |
383 | ||
384 | platform_set_drvdata(pdev, NULL); | |
385 | ||
386 | return 0; | |
387 | } | |
388 | ||
389 | static struct platform_driver mxs_i2c_driver = { | |
390 | .driver = { | |
391 | .name = DRIVER_NAME, | |
392 | .owner = THIS_MODULE, | |
393 | }, | |
394 | .remove = __devexit_p(mxs_i2c_remove), | |
395 | }; | |
396 | ||
397 | static int __init mxs_i2c_init(void) | |
398 | { | |
399 | return platform_driver_probe(&mxs_i2c_driver, mxs_i2c_probe); | |
400 | } | |
401 | subsys_initcall(mxs_i2c_init); | |
402 | ||
403 | static void __exit mxs_i2c_exit(void) | |
404 | { | |
405 | platform_driver_unregister(&mxs_i2c_driver); | |
406 | } | |
407 | module_exit(mxs_i2c_exit); | |
408 | ||
409 | MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>"); | |
410 | MODULE_DESCRIPTION("MXS I2C Bus Driver"); | |
411 | MODULE_LICENSE("GPL"); | |
412 | MODULE_ALIAS("platform:" DRIVER_NAME); |