]> git.openfabrics.org - ~shefty/rdma-dev.git/blob - drivers/i2c/busses/i2c-mxs.c
Merge branch 'i2c-embedded/for-3.3' of git://git.pengutronix.de/git/wsa/linux-2.6
[~shefty/rdma-dev.git] / drivers / i2c / busses / i2c-mxs.c
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 #define MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK  0x0000001F
76
77 #define MXS_I2C_QUEUECMD        (0x80)
78
79 #define MXS_I2C_QUEUEDATA       (0x90)
80
81 #define MXS_I2C_DATA            (0xa0)
82
83
84 #define MXS_CMD_I2C_SELECT      (MXS_I2C_CTRL0_RETAIN_CLOCK |   \
85                                  MXS_I2C_CTRL0_PRE_SEND_START | \
86                                  MXS_I2C_CTRL0_MASTER_MODE |    \
87                                  MXS_I2C_CTRL0_DIRECTION |      \
88                                  MXS_I2C_CTRL0_XFER_COUNT(1))
89
90 #define MXS_CMD_I2C_WRITE       (MXS_I2C_CTRL0_PRE_SEND_START | \
91                                  MXS_I2C_CTRL0_MASTER_MODE |    \
92                                  MXS_I2C_CTRL0_DIRECTION)
93
94 #define MXS_CMD_I2C_READ        (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
95                                  MXS_I2C_CTRL0_MASTER_MODE)
96
97 /**
98  * struct mxs_i2c_dev - per device, private MXS-I2C data
99  *
100  * @dev: driver model device node
101  * @regs: IO registers pointer
102  * @cmd_complete: completion object for transaction wait
103  * @cmd_err: error code for last transaction
104  * @adapter: i2c subsystem adapter node
105  */
106 struct mxs_i2c_dev {
107         struct device *dev;
108         void __iomem *regs;
109         struct completion cmd_complete;
110         u32 cmd_err;
111         struct i2c_adapter adapter;
112 };
113
114 /*
115  * TODO: check if calls to here are really needed. If not, we could get rid of
116  * mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably.
117  */
118 static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
119 {
120         mxs_reset_block(i2c->regs);
121         writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
122         writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
123                         i2c->regs + MXS_I2C_QUEUECTRL_SET);
124 }
125
126 static void mxs_i2c_pioq_setup_read(struct mxs_i2c_dev *i2c, u8 addr, int len,
127                                         int flags)
128 {
129         u32 data;
130
131         writel(MXS_CMD_I2C_SELECT, i2c->regs + MXS_I2C_QUEUECMD);
132
133         data = (addr << 1) | I2C_SMBUS_READ;
134         writel(data, i2c->regs + MXS_I2C_DATA);
135
136         data = MXS_CMD_I2C_READ | MXS_I2C_CTRL0_XFER_COUNT(len) | flags;
137         writel(data, i2c->regs + MXS_I2C_QUEUECMD);
138 }
139
140 static void mxs_i2c_pioq_setup_write(struct mxs_i2c_dev *i2c,
141                                     u8 addr, u8 *buf, int len, int flags)
142 {
143         u32 data;
144         int i, shifts_left;
145
146         data = MXS_CMD_I2C_WRITE | MXS_I2C_CTRL0_XFER_COUNT(len + 1) | flags;
147         writel(data, i2c->regs + MXS_I2C_QUEUECMD);
148
149         /*
150          * We have to copy the slave address (u8) and buffer (arbitrary number
151          * of u8) into the data register (u32). To achieve that, the u8 are put
152          * into the MSBs of 'data' which is then shifted for the next u8. When
153          * appropriate, 'data' is written to MXS_I2C_DATA. So, the first u32
154          * looks like this:
155          *
156          *  3          2          1          0
157          * 10987654|32109876|54321098|76543210
158          * --------+--------+--------+--------
159          * buffer+2|buffer+1|buffer+0|slave_addr
160          */
161
162         data = ((addr << 1) | I2C_SMBUS_WRITE) << 24;
163
164         for (i = 0; i < len; i++) {
165                 data >>= 8;
166                 data |= buf[i] << 24;
167                 if ((i & 3) == 2)
168                         writel(data, i2c->regs + MXS_I2C_DATA);
169         }
170
171         /* Write out the remaining bytes if any */
172         shifts_left = 24 - (i & 3) * 8;
173         if (shifts_left)
174                 writel(data >> shifts_left, i2c->regs + MXS_I2C_DATA);
175 }
176
177 /*
178  * TODO: should be replaceable with a waitqueue and RD_QUEUE_IRQ (setting the
179  * rd_threshold to 1). Couldn't get this to work, though.
180  */
181 static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c)
182 {
183         unsigned long timeout = jiffies + msecs_to_jiffies(1000);
184
185         while (readl(i2c->regs + MXS_I2C_QUEUESTAT)
186                         & MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY) {
187                         if (time_after(jiffies, timeout))
188                                 return -ETIMEDOUT;
189                         cond_resched();
190         }
191
192         return 0;
193 }
194
195 static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len)
196 {
197         u32 data;
198         int i;
199
200         for (i = 0; i < len; i++) {
201                 if ((i & 3) == 0) {
202                         if (mxs_i2c_wait_for_data(i2c))
203                                 return -ETIMEDOUT;
204                         data = readl(i2c->regs + MXS_I2C_QUEUEDATA);
205                 }
206                 buf[i] = data & 0xff;
207                 data >>= 8;
208         }
209
210         return 0;
211 }
212
213 /*
214  * Low level master read/write transaction.
215  */
216 static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
217                                 int stop)
218 {
219         struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
220         int ret;
221         int flags;
222
223         dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
224                 msg->addr, msg->len, msg->flags, stop);
225
226         if (msg->len == 0)
227                 return -EINVAL;
228
229         init_completion(&i2c->cmd_complete);
230
231         flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
232
233         if (msg->flags & I2C_M_RD)
234                 mxs_i2c_pioq_setup_read(i2c, msg->addr, msg->len, flags);
235         else
236                 mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf, msg->len,
237                                         flags);
238
239         writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
240                         i2c->regs + MXS_I2C_QUEUECTRL_SET);
241
242         ret = wait_for_completion_timeout(&i2c->cmd_complete,
243                                                 msecs_to_jiffies(1000));
244         if (ret == 0)
245                 goto timeout;
246
247         if ((!i2c->cmd_err) && (msg->flags & I2C_M_RD)) {
248                 ret = mxs_i2c_finish_read(i2c, msg->buf, msg->len);
249                 if (ret)
250                         goto timeout;
251         }
252
253         if (i2c->cmd_err == -ENXIO)
254                 mxs_i2c_reset(i2c);
255
256         dev_dbg(i2c->dev, "Done with err=%d\n", i2c->cmd_err);
257
258         return i2c->cmd_err;
259
260 timeout:
261         dev_dbg(i2c->dev, "Timeout!\n");
262         mxs_i2c_reset(i2c);
263         return -ETIMEDOUT;
264 }
265
266 static int mxs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
267                         int num)
268 {
269         int i;
270         int err;
271
272         for (i = 0; i < num; i++) {
273                 err = mxs_i2c_xfer_msg(adap, &msgs[i], i == (num - 1));
274                 if (err)
275                         return err;
276         }
277
278         return num;
279 }
280
281 static u32 mxs_i2c_func(struct i2c_adapter *adap)
282 {
283         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
284 }
285
286 static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
287 {
288         struct mxs_i2c_dev *i2c = dev_id;
289         u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK;
290         bool is_last_cmd;
291
292         if (!stat)
293                 return IRQ_NONE;
294
295         if (stat & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
296                 i2c->cmd_err = -ENXIO;
297         else if (stat & (MXS_I2C_CTRL1_EARLY_TERM_IRQ |
298                     MXS_I2C_CTRL1_MASTER_LOSS_IRQ |
299                     MXS_I2C_CTRL1_SLAVE_STOP_IRQ | MXS_I2C_CTRL1_SLAVE_IRQ))
300                 /* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */
301                 i2c->cmd_err = -EIO;
302         else
303                 i2c->cmd_err = 0;
304
305         is_last_cmd = (readl(i2c->regs + MXS_I2C_QUEUESTAT) &
306                 MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK) == 0;
307
308         if (is_last_cmd || i2c->cmd_err)
309                 complete(&i2c->cmd_complete);
310
311         writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
312
313         return IRQ_HANDLED;
314 }
315
316 static const struct i2c_algorithm mxs_i2c_algo = {
317         .master_xfer = mxs_i2c_xfer,
318         .functionality = mxs_i2c_func,
319 };
320
321 static int __devinit mxs_i2c_probe(struct platform_device *pdev)
322 {
323         struct device *dev = &pdev->dev;
324         struct mxs_i2c_dev *i2c;
325         struct i2c_adapter *adap;
326         struct resource *res;
327         resource_size_t res_size;
328         int err, irq;
329
330         i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL);
331         if (!i2c)
332                 return -ENOMEM;
333
334         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
335         if (!res)
336                 return -ENOENT;
337
338         res_size = resource_size(res);
339         if (!devm_request_mem_region(dev, res->start, res_size, res->name))
340                 return -EBUSY;
341
342         i2c->regs = devm_ioremap_nocache(dev, res->start, res_size);
343         if (!i2c->regs)
344                 return -EBUSY;
345
346         irq = platform_get_irq(pdev, 0);
347         if (irq < 0)
348                 return irq;
349
350         err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c);
351         if (err)
352                 return err;
353
354         i2c->dev = dev;
355         platform_set_drvdata(pdev, i2c);
356
357         /* Do reset to enforce correct startup after pinmuxing */
358         mxs_i2c_reset(i2c);
359
360         adap = &i2c->adapter;
361         strlcpy(adap->name, "MXS I2C adapter", sizeof(adap->name));
362         adap->owner = THIS_MODULE;
363         adap->algo = &mxs_i2c_algo;
364         adap->dev.parent = dev;
365         adap->nr = pdev->id;
366         i2c_set_adapdata(adap, i2c);
367         err = i2c_add_numbered_adapter(adap);
368         if (err) {
369                 dev_err(dev, "Failed to add adapter (%d)\n", err);
370                 writel(MXS_I2C_CTRL0_SFTRST,
371                                 i2c->regs + MXS_I2C_CTRL0_SET);
372                 return err;
373         }
374
375         return 0;
376 }
377
378 static int __devexit mxs_i2c_remove(struct platform_device *pdev)
379 {
380         struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev);
381         int ret;
382
383         ret = i2c_del_adapter(&i2c->adapter);
384         if (ret)
385                 return -EBUSY;
386
387         writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
388                         i2c->regs + MXS_I2C_QUEUECTRL_CLR);
389         writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
390
391         platform_set_drvdata(pdev, NULL);
392
393         return 0;
394 }
395
396 static struct platform_driver mxs_i2c_driver = {
397         .driver = {
398                    .name = DRIVER_NAME,
399                    .owner = THIS_MODULE,
400                    },
401         .remove = __devexit_p(mxs_i2c_remove),
402 };
403
404 static int __init mxs_i2c_init(void)
405 {
406         return platform_driver_probe(&mxs_i2c_driver, mxs_i2c_probe);
407 }
408 subsys_initcall(mxs_i2c_init);
409
410 static void __exit mxs_i2c_exit(void)
411 {
412         platform_driver_unregister(&mxs_i2c_driver);
413 }
414 module_exit(mxs_i2c_exit);
415
416 MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
417 MODULE_DESCRIPTION("MXS I2C Bus Driver");
418 MODULE_LICENSE("GPL");
419 MODULE_ALIAS("platform:" DRIVER_NAME);