summaryrefslogtreecommitdiff
path: root/package/kernel/i2c-gpio-custom/src/i2c-gpio-custom.c
blob: 921d290d5206cd1198255a1391f2b4fbd2a1c58b (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
/*
 *  Custom GPIO-based I2C driver
 *
 *  Copyright (C) 2007-2008 Gabor Juhos <juhosg@openwrt.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 * ---------------------------------------------------------------------------
 *
 *  The behaviour of this driver can be altered by setting some parameters
 *  from the insmod command line.
 *
 *  The following parameters are adjustable:
 *
 *	bus0	These four arguments can be arrays of
 *	bus1	1-8 unsigned integers as follows:
 *	bus2
 *	bus3	<id>,<sda>,<scl>,<udelay>,<timeout>,<sda_od>,<scl_od>,<scl_oo>
 *
 *  where:
 *
 *  <id>	ID to used as device_id for the corresponding bus (required)
 *  <sda>	GPIO pin ID to used for SDA (required)
 *  <scl>	GPIO pin ID to used for SCL (required)
 *  <udelay>	signal toggle delay.
 *  <timeout>	clock stretching timeout.
 *  <sda_od>	SDA is configured as open drain.
 *  <scl_od>	SCL is configured as open drain.
 *  <scl_oo>	SCL output drivers cannot be turned off.
 *
 *  See include/i2c-gpio.h for more information about the parameters.
 *
 *  If this driver is built into the kernel, you can use the following kernel
 *  command line parameters, with the same values as the corresponding module
 *  parameters listed above:
 *
 *	i2c-gpio-custom.bus0
 *	i2c-gpio-custom.bus1
 *	i2c-gpio-custom.bus2
 *	i2c-gpio-custom.bus3
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>

#include <linux/i2c-gpio.h>

#define DRV_NAME	"i2c-gpio-custom"
#define DRV_DESC	"Custom GPIO-based I2C driver"
#define DRV_VERSION	"0.1.1"

#define PFX		DRV_NAME ": "

#define BUS_PARAM_ID		0
#define BUS_PARAM_SDA		1
#define BUS_PARAM_SCL		2
#define BUS_PARAM_UDELAY	3
#define BUS_PARAM_TIMEOUT	4
#define BUS_PARAM_SDA_OD	5
#define BUS_PARAM_SCL_OD	6
#define BUS_PARAM_SCL_OO	7

#define BUS_PARAM_REQUIRED	3
#define BUS_PARAM_COUNT		8
#define BUS_COUNT_MAX		4

static unsigned int bus0[BUS_PARAM_COUNT] __initdata;
static unsigned int bus1[BUS_PARAM_COUNT] __initdata;
static unsigned int bus2[BUS_PARAM_COUNT] __initdata;
static unsigned int bus3[BUS_PARAM_COUNT] __initdata;

static unsigned int bus_nump[BUS_COUNT_MAX] __initdata;

#define BUS_PARM_DESC \
	" config -> id,sda,scl[,udelay,timeout,sda_od,scl_od,scl_oo]"

module_param_array(bus0, uint, &bus_nump[0], 0);
MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC);
module_param_array(bus1, uint, &bus_nump[1], 0);
MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC);
module_param_array(bus2, uint, &bus_nump[2], 0);
MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC);
module_param_array(bus3, uint, &bus_nump[3], 0);
MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC);

static struct platform_device *devices[BUS_COUNT_MAX];
static unsigned int nr_devices;

static void i2c_gpio_custom_cleanup(void)
{
	int i;

	for (i = 0; i < nr_devices; i++)
		if (devices[i])
			platform_device_put(devices[i]);
}

static int __init i2c_gpio_custom_add_one(unsigned int id, unsigned int *params)
{
	struct platform_device *pdev;
	struct i2c_gpio_platform_data pdata;
	int err;

	if (!bus_nump[id])
		return 0;

	if (bus_nump[id] < BUS_PARAM_REQUIRED) {
		printk(KERN_ERR PFX "not enough parameters for bus%d\n", id);
		err = -EINVAL;
		goto err;
	}

	pdev = platform_device_alloc("i2c-gpio", params[BUS_PARAM_ID]);
	if (!pdev) {
		err = -ENOMEM;
		goto err;
	}

	pdata.sda_pin = params[BUS_PARAM_SDA];
	pdata.scl_pin = params[BUS_PARAM_SCL];
	pdata.udelay = params[BUS_PARAM_UDELAY];
	pdata.timeout = params[BUS_PARAM_TIMEOUT];
	pdata.sda_is_open_drain = params[BUS_PARAM_SDA_OD] != 0;
	pdata.scl_is_open_drain = params[BUS_PARAM_SCL_OD] != 0;
	pdata.scl_is_output_only = params[BUS_PARAM_SCL_OO] != 0;

	err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
	if (err)
		goto err_put;

	err = platform_device_add(pdev);
	if (err)
		goto err_put;

	devices[nr_devices++] = pdev;
	return 0;

err_put:
	platform_device_put(pdev);
err:
	return err;
}

static int __init i2c_gpio_custom_probe(void)
{
	int err;

	printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");

	err = i2c_gpio_custom_add_one(0, bus0);
	if (err)
		goto err;

	err = i2c_gpio_custom_add_one(1, bus1);
	if (err)
		goto err;

	err = i2c_gpio_custom_add_one(2, bus2);
	if (err)
		goto err;

	err = i2c_gpio_custom_add_one(3, bus3);
	if (err)
		goto err;

	if (!nr_devices) {
		printk(KERN_ERR PFX "no bus parameter(s) specified\n");
		err = -ENODEV;
		goto err;
	}

	return 0;

err:
	i2c_gpio_custom_cleanup();
	return err;
}

#ifdef MODULE
static int __init i2c_gpio_custom_init(void)
{
	return i2c_gpio_custom_probe();
}
module_init(i2c_gpio_custom_init);

static void __exit i2c_gpio_custom_exit(void)
{
	i2c_gpio_custom_cleanup();
}
module_exit(i2c_gpio_custom_exit);
#else
subsys_initcall(i2c_gpio_custom_probe);
#endif /* MODULE*/

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org >");
MODULE_DESCRIPTION(DRV_DESC);
MODULE_VERSION(DRV_VERSION);