summaryrefslogtreecommitdiffstats
path: root/package/ucmb/src/ucmb.c
blob: 4807f95ce33a41cb0b3d1f55bbe79c98ec601875 (plain)
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
/*
 * Microcontroller Message Bus
 *
 * Copyright (c) 2009 Michael Buesch <mb@bu3sch.de>
 *
 * Licensed under the GNU/GPL. See COPYING for details.
 */

#include "ucmb.h"

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_gpio.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/gfp.h>


#define PFX	"ucmb: "


MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Microcontroller Message Bus");
MODULE_AUTHOR("Michael Buesch");


struct ucmb {
	/* Misc character device driver */
	struct miscdevice mdev;
	struct file_operations mdev_fops;

	/* SPI driver */
	struct spi_device *sdev;

	/* SPI-GPIO driver */
	struct spi_gpio_platform_data spi_gpio_pdata;
	struct platform_device spi_gpio_pdev;
};

static int ucmb_spi_busnum_count = 1337;


static struct ucmb_platform_data ucmb_list[] = {
	{ //FIXME don't define it here.
		.name		= "ucmb",
		.gpio_sck	= 0,
		.gpio_miso	= 1,
		.gpio_mosi	= 2,
	},
};


static int __devinit ucmb_spi_probe(struct spi_device *sdev)
{
	return 0;
}

static int __devexit ucmb_spi_remove(struct spi_device *sdev)
{
	return 0;
}

static struct spi_driver ucmb_spi_driver = {
	.driver		= {
		.name	= "ucmb",
		.bus	= &spi_bus_type,
		.owner	= THIS_MODULE,
	},
	.probe		= ucmb_spi_probe,
	.remove		= __devexit_p(ucmb_spi_remove),
};

static inline struct ucmb * filp_to_ucmb(struct file *filp)
{
	return container_of(filp->f_op, struct ucmb, mdev_fops);
}

/* FIXME offp */
static ssize_t ucmb_read(struct file *filp, char __user *user_buf,
			 size_t size, loff_t *offp)
{
	struct ucmb *ucmb = filp_to_ucmb(filp);
	u8 *buf;
	int err;

	err = -E2BIG;
	if (size > PAGE_SIZE)
		goto out;

	err = -ENOMEM;
	buf = (char *)__get_free_page(GFP_KERNEL);
	if (!buf)
		goto out;

	err = spi_read(ucmb->sdev, buf, size);
	if (err)
		goto out_free;

	err = -EFAULT;
	if (copy_to_user(user_buf, buf, size))
		goto out_free;

	err = 0;

out_free:
	__free_page((unsigned long)buf);
out:
	return err ? err : size;
}

/* FIXME offp */
static ssize_t ucmb_write(struct file *filp, const char __user *user_buf,
			  size_t size, loff_t *offp)
{
	struct ucmb *ucmb = filp_to_ucmb(filp);
	u8 *buf;
	int err;

	err = -ENOMEM;
	buf = (char *)__get_free_page(GFP_KERNEL);
	if (!buf)
		goto out;

	size = min(PAGE_SIZE, size);
	err = -EFAULT;
	if (copy_from_user(buf, user_buf, size))
		goto out_free;

	err = spi_write(ucmb->sdev, buf, size);

out_free:
	__free_page((unsigned long)buf);
out:
	return err ? err : size;
}

static int __devinit ucmb_probe(struct platform_device *pdev)
{
	struct ucmb_platform_data *pdata;
	struct ucmb *ucmb;
	int err;
	const int bus_num = ucmb_spi_busnum_count++;
	struct spi_bitbang *bb;

	pdata = pdev->dev.platform_data;
	if (!pdata)
		return -ENXIO;

	ucmb = kzalloc(sizeof(struct ucmb), GFP_KERNEL);
	if (!ucmb)
		return -ENOMEM;

	/* Create the SPI GPIO bus master. */

#ifdef CONFIG_SPI_GPIO_MODULE
	err = request_module("spi_gpio");
	if (err)
		printk(KERN_WARNING PFX "Failed to request spi_gpio module\n");
#endif /* CONFIG_SPI_GPIO_MODULE */

	ucmb->spi_gpio_pdata.sck = pdata->gpio_sck;
	ucmb->spi_gpio_pdata.mosi = pdata->gpio_mosi;
	ucmb->spi_gpio_pdata.miso = pdata->gpio_miso;
	ucmb->spi_gpio_pdata.num_chipselect = 1;

	ucmb->spi_gpio_pdev.name = "spi_gpio";
	ucmb->spi_gpio_pdev.id = bus_num;
	ucmb->spi_gpio_pdev.dev.platform_data = &ucmb->spi_gpio_pdata;

	err = platform_device_register(&ucmb->spi_gpio_pdev);
	if (err) {
		printk(KERN_ERR PFX "Failed to register SPI-GPIO platform device\n");
		goto err_free_ucmb;
	}
	bb = platform_get_drvdata(&ucmb->spi_gpio_pdev);
	if (!bb || !bb->master) {
		printk(KERN_ERR PFX "No bitbanged master device found.\n");
		goto err_unreg_spi_gpio_pdev;
	}

	/* Create the SPI device. */

	ucmb->sdev = spi_alloc_device(bb->master);
	if (!ucmb->sdev) {
		printk(KERN_ERR PFX "Failed to allocate SPI device\n");
		goto err_unreg_spi_gpio_pdev;
	}
	ucmb->sdev->max_speed_hz = 5000000;
	ucmb->sdev->chip_select = 0;
	ucmb->sdev->mode = SPI_MODE_0;
	strlcpy(ucmb->sdev->modalias, "ucmb", /* We are the SPI driver. */
		sizeof(ucmb->sdev->modalias));
	ucmb->sdev->controller_data = (void *)SPI_GPIO_NO_CHIPSELECT;
	err = spi_add_device(ucmb->sdev);
	if (err) {
		printk(KERN_ERR PFX "Failed to add SPI device\n");
		goto err_free_spi_device;
	}

	/* Create the Misc char device. */

	ucmb->mdev.minor = MISC_DYNAMIC_MINOR;
	ucmb->mdev.name = pdata->name;
	ucmb->mdev.parent = &pdev->dev;
	ucmb->mdev_fops.read = ucmb_read;
	ucmb->mdev_fops.write = ucmb_write;
	ucmb->mdev.fops = &ucmb->mdev_fops;

	err = misc_register(&ucmb->mdev);
	if (err) {
		printk(KERN_ERR PFX "Failed to register miscdev %s\n",
		       ucmb->mdev.name);
		goto err_unreg_spi_device;
	}

	platform_set_drvdata(pdev, ucmb);

	printk(KERN_INFO PFX "Registered message bus \"%s\"\n", pdata->name);

	return 0;

err_unreg_spi_device:
	spi_unregister_device(ucmb->sdev);
err_free_spi_device:
	spi_dev_put(ucmb->sdev);
err_unreg_spi_gpio_pdev:
	platform_device_unregister(&ucmb->spi_gpio_pdev);
err_free_ucmb:
	kfree(ucmb);

	return err;
}

static int __devexit ucmb_remove(struct platform_device *pdev)
{
	struct ucmb *ucmb = platform_get_drvdata(pdev);
	int err;

	err = misc_deregister(&ucmb->mdev);
	if (err) {
		printk(KERN_ERR PFX "Failed to unregister miscdev %s\n",
		       ucmb->mdev.name);
	}
	spi_unregister_device(ucmb->sdev);
	spi_dev_put(ucmb->sdev);
	platform_device_unregister(&ucmb->spi_gpio_pdev);

	kfree(ucmb);
	platform_set_drvdata(pdev, NULL);

	return 0;
}

static struct platform_driver ucmb_driver = {
	.driver		= {
		.name	= "ucmb",
		.owner	= THIS_MODULE,
	},
	.probe		= ucmb_probe,
	.remove		= __devexit_p(ucmb_probe),
};

static int ucmb_modinit(void)
{
	struct ucmb_platform_data *pdata;
	struct platform_device *pdev;
	int err, i;

	printk(KERN_INFO "Microcontroller message bus driver\n");

	err = platform_driver_register(&ucmb_driver);
	if (err) {
		printk(KERN_ERR PFX "Failed to register platform driver\n");
		return err;
	}
	err = spi_register_driver(&ucmb_spi_driver);
	if (err) {
		printk(KERN_ERR PFX "Failed to register SPI driver\n");
		platform_driver_unregister(&ucmb_driver);
		return err;
	}

	for (i = 0; i < ARRAY_SIZE(ucmb_list); i++) {
		pdata = &ucmb_list[i];

		pdev = platform_device_alloc("ucmb", i);
		if (!pdev) {
			printk(KERN_ERR PFX "Failed to allocate platform device.\n");
			break;
		}
		err = platform_device_add_data(pdev, pdata, sizeof(*pdata));
		if (err) {
			printk(KERN_ERR PFX "Failed to add platform data.\n");
			platform_device_put(pdev);
			break;
		}
		err = platform_device_add(pdev);
		if (err) {
			printk(KERN_ERR PFX "Failed to register platform device.\n");
			platform_device_put(pdev);
			break;
		}
		pdata->pdev = pdev;
	}

	return 0;
}
module_init(ucmb_modinit);

static void ucmb_modexit(void)
{
	struct ucmb_platform_data *pdata;
	int i;

	for (i = 0; i < ARRAY_SIZE(ucmb_list); i++) {
		pdata = &ucmb_list[i];

		if (pdata->pdev) {
			platform_device_unregister(pdata->pdev);
			platform_device_put(pdata->pdev);
		}
	}
	spi_unregister_driver(&ucmb_spi_driver);
	platform_driver_unregister(&ucmb_driver);
}
module_exit(ucmb_modexit);