1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
|
/*
* Copyright (C) 2007-2010 Freescale Semiconductor, Inc. All Rights Reserved.
*/
/*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/slab.h>
#include <asm/io.h>
#include <linux/pm.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include "i2c_slave_device.h"
#include "mxc_i2c_slave.h"
#include "mxc_i2c_slave_reg.h"
struct mxc_i2c_slave_clk {
int reg_value;
int div;
};
static const struct mxc_i2c_slave_clk i2c_clk_table[] = {
{0x20, 22}, {0x21, 24}, {0x22, 26}, {0x23, 28},
{0, 30}, {1, 32}, {0x24, 32}, {2, 36},
{0x25, 36}, {0x26, 40}, {3, 42}, {0x27, 44},
{4, 48}, {0x28, 48}, {5, 52}, {0x29, 56},
{6, 60}, {0x2A, 64}, {7, 72}, {0x2B, 72},
{8, 80}, {0x2C, 80}, {9, 88}, {0x2D, 96},
{0xA, 104}, {0x2E, 112}, {0xB, 128}, {0x2F, 128},
{0xC, 144}, {0xD, 160}, {0x30, 160}, {0xE, 192},
{0x31, 192}, {0x32, 224}, {0xF, 240}, {0x33, 256},
{0x10, 288}, {0x11, 320}, {0x34, 320}, {0x12, 384},
{0x35, 384}, {0x36, 448}, {0x13, 480}, {0x37, 512},
{0x14, 576}, {0x15, 640}, {0x38, 640}, {0x16, 768},
{0x39, 768}, {0x3A, 896}, {0x17, 960}, {0x3B, 1024},
{0x18, 1152}, {0x19, 1280}, {0x3C, 1280}, {0x1A, 1536},
{0x3D, 1536}, {0x3E, 1792}, {0x1B, 1920}, {0x3F, 2048},
{0x1C, 2304}, {0x1D, 2560}, {0x1E, 3072}, {0x1F, 3840},
{0, 0}
};
extern void gpio_i2c_active(int i2c_num);
extern void gpio_i2c_inactive(int i2c_num);
static irqreturn_t interrupt_handler(int irq, void *dev_id)
{
u16 status, ctl;
int num;
u16 data;
struct mxc_i2c_slave_device *mxc_i2c =
(struct mxc_i2c_slave_device *)dev_id;
status = readw(mxc_i2c->reg_base + MXC_I2SR);
ctl = readw(mxc_i2c->reg_base + MXC_I2CR);
dev_dbg(mxc_i2c->dev->dev, "status=%x, ctl=%x\n", status, ctl);
if (status & MXC_I2SR_IAAS) {
if (status & MXC_I2SR_SRW) {
/*slave send */
num =
i2c_slave_device_consume(mxc_i2c->dev, 1,
(u8 *) &data);
if (num < 1) {
/*FIXME:not ready to send data */
printk(KERN_ERR
" i2c-slave:%s:data not ready\n",
__func__);
} else {
ctl |= MXC_I2CR_MTX;
writew(ctl, mxc_i2c->reg_base + MXC_I2CR);
/*send data */
writew(data, mxc_i2c->reg_base + MXC_I2DR);
}
} else {
/*slave receive */
ctl &= ~MXC_I2CR_MTX;
writew(ctl, mxc_i2c->reg_base + MXC_I2CR);
/*dummy read */
data = readw(mxc_i2c->reg_base + MXC_I2DR);
}
} else {
/*slave send */
if (ctl & MXC_I2CR_MTX) {
if (!(status & MXC_I2SR_RXAK)) { /*ACK received */
num =
i2c_slave_device_consume(mxc_i2c->dev, 1,
(u8 *) &data);
if (num < 1) {
/*FIXME:not ready to send data */
printk(KERN_ERR
" i2c-slave:%s:data not ready\n",
__func__);
} else {
ctl |= MXC_I2CR_MTX;
writew(ctl,
mxc_i2c->reg_base + MXC_I2CR);
writew(data,
mxc_i2c->reg_base + MXC_I2DR);
}
} else {
/*no ACK. */
/*dummy read */
ctl &= ~MXC_I2CR_MTX;
writew(ctl, mxc_i2c->reg_base + MXC_I2CR);
data = readw(mxc_i2c->reg_base + MXC_I2DR);
}
} else { /*read */
ctl &= ~MXC_I2CR_MTX;
writew(ctl, mxc_i2c->reg_base + MXC_I2CR);
/*read */
data = readw(mxc_i2c->reg_base + MXC_I2DR);
i2c_slave_device_produce(mxc_i2c->dev, 1,
(u8 *) &data);
}
}
writew(0x0, mxc_i2c->reg_base + MXC_I2SR);
return IRQ_HANDLED;
}
static int start(i2c_slave_device_t *device)
{
volatile unsigned int cr;
unsigned int addr;
struct mxc_i2c_slave_device *mxc_dev;
mxc_dev = (struct mxc_i2c_slave_device *)device->private_data;
if (!mxc_dev) {
dev_err(device->dev, "%s: get mxc_dev error\n", __func__);
return -ENODEV;
}
clk_enable(mxc_dev->clk);
/* Set the frequency divider */
writew(mxc_dev->clkdiv, mxc_dev->reg_base + MXC_IFDR);
/* Set the Slave bit */
cr = readw(mxc_dev->reg_base + MXC_I2CR);
cr &= (!MXC_I2CR_MSTA);
writew(cr, mxc_dev->reg_base + MXC_I2CR);
/*Set Slave Address */
addr = mxc_dev->dev->address << 1;
writew(addr, mxc_dev->reg_base + MXC_IADR);
/* Clear the status register */
writew(0x0, mxc_dev->reg_base + MXC_I2SR);
/* Enable I2C and its interrupts */
writew(MXC_I2CR_IEN, mxc_dev->reg_base + MXC_I2CR);
writew(MXC_I2CR_IEN | MXC_I2CR_IIEN, mxc_dev->reg_base + MXC_I2CR);
return 0;
}
static int stop(i2c_slave_device_t *device)
{
struct mxc_i2c_slave_device *mxc_dev;
mxc_dev = (struct mxc_i2c_slave_device *)device->private_data;
writew(0x0, mxc_dev->reg_base + MXC_I2CR);
clk_disable(mxc_dev->clk);
return 0;
}
static int mxc_i2c_slave_probe(struct platform_device *pdev)
{
int i;
u32 clk_freq;
struct resource *res;
struct mxc_i2c_slave_device *mxc_dev;
mxc_dev = kzalloc(sizeof(struct mxc_i2c_slave_device), GFP_KERNEL);
if (!mxc_dev) {
goto error0;
}
mxc_dev->dev = i2c_slave_device_alloc();
if (mxc_dev->dev == 0) {
dev_err(&pdev->dev, "%s: i2c_slave_device_alloc error\n",
__func__);
goto error1;
}
i2c_slave_device_set_address(mxc_dev->dev, MXC_I2C_SLAVE_ADDRESS);
i2c_slave_device_set_freq(mxc_dev->dev, MXC_I2C_SLAVE_FREQ);
i2c_slave_device_set_name(mxc_dev->dev, MXC_I2C_SLAVE_NAME);
mxc_dev->dev->start = start;
mxc_dev->dev->stop = stop;
mxc_dev->dev->private_data = mxc_dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&pdev->dev, "%s: get resource error\n", __func__);
goto error2;
}
mxc_dev->reg_base = ioremap(res->start, res->end - res->start + 1);
mxc_dev->irq = platform_get_irq(pdev, 0);
if (mxc_dev->irq < 0) {
dev_err(&pdev->dev, "%s: get irq error\n", __func__);
goto error3;
}
if (request_irq(mxc_dev->irq, interrupt_handler,
0, mxc_dev->dev->name, mxc_dev) < 0) {
dev_err(&pdev->dev, "%s: request_irq error\n", __func__);
goto error3;
}
/*i2c id on soc */
mxc_dev->id = pdev->id;
gpio_i2c_active(mxc_dev->id);
/*clock */
mxc_dev->clk = clk_get(&pdev->dev, "i2c_clk");
clk_freq = clk_get_rate(mxc_dev->clk);
mxc_dev->clkdiv = -1;
if (mxc_dev->dev->scl_freq) {
/* Calculate divider and round up any fractional part */
int div = (clk_freq + mxc_dev->dev->scl_freq - 1) /
mxc_dev->dev->scl_freq;
for (i = 0; i2c_clk_table[i].div != 0; i++) {
if (i2c_clk_table[i].div >= div) {
mxc_dev->clkdiv = i2c_clk_table[i].reg_value;
break;
}
}
}
if (mxc_dev->clkdiv == -1) {
i--;
mxc_dev->clkdiv = 0x1F; /* Use max divider */
}
dev_dbg(&pdev->dev,
"i2c slave speed is %d/%d = %d bps, reg val = 0x%02X\n",
clk_freq, i2c_clk_table[i].div, clk_freq / i2c_clk_table[i].div,
mxc_dev->clkdiv);
if (i2c_slave_device_register(mxc_dev->dev) < 0) {
dev_err(&pdev->dev, "%s: i2c_slave_device_register error\n",
__func__);
goto error4;
}
platform_set_drvdata(pdev, (void *)mxc_dev);
/*start(mxc_dev->dev); */
return 0;
error4:
free_irq(mxc_dev->irq, mxc_dev);
error3:
iounmap(mxc_dev->reg_base);
error2:
i2c_slave_device_free(mxc_dev->dev);
error1:
kfree(mxc_dev);
error0:
return -ENODEV;
}
static int mxc_i2c_slave_remove(struct platform_device *pdev)
{
struct mxc_i2c_slave_device *mxc_dev;
mxc_dev = (struct mxc_i2c_slave_device *)platform_get_drvdata(pdev);
i2c_slave_device_unregister(mxc_dev->dev);
free_irq(mxc_dev->irq, mxc_dev);
iounmap(mxc_dev->reg_base);
kfree((void *)mxc_dev);
return 0;
}
static int mxc_i2c_slave_suspend(struct platform_device *pdev,
pm_message_t state)
{
return 0;
}
static int mxc_i2c_slave_resume(struct platform_device *pdev)
{
return 0;
}
static struct platform_driver mxci2c_slave_driver = {
.driver = {
.name = "mxc_i2c_slave",
.owner = THIS_MODULE,
},
.probe = mxc_i2c_slave_probe,
.remove = mxc_i2c_slave_remove,
.suspend = mxc_i2c_slave_suspend,
.resume = mxc_i2c_slave_resume,
};
static int __init mxc_i2c_slave_init(void)
{
/* Register the device driver structure. */
return platform_driver_register(&mxci2c_slave_driver);
}
/*!
* This function is used to cleanup all resources before the driver exits.
*/
static void __exit mxc_i2c_slave_exit(void)
{
platform_driver_unregister(&mxci2c_slave_driver);
}
module_init(mxc_i2c_slave_init);
module_exit(mxc_i2c_slave_exit);
MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("MXC I2C Slave Driver");
MODULE_LICENSE("GPL");
|
