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
|
/*
* Helper module for board specific I2C bus registration
*
* Copyright (C) 2009 Nokia Corporation.
*
* 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.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
*/
#include "common.h"
#include <plat/omap_hwmod.h>
#include <plat/omap_device.h>
#include "mux.h"
#include "i2c.h"
/* In register I2C_CON, Bit 15 is the I2C enable bit */
#define I2C_EN BIT(15)
#define OMAP2_I2C_CON_OFFSET 0x24
#define OMAP4_I2C_CON_OFFSET 0xA4
/* Maximum microseconds to wait for OMAP module to softreset */
#define MAX_MODULE_SOFTRESET_WAIT 10000
#define MAX_OMAP_I2C_HWMOD_NAME_LEN 16
static void __init omap2_i2c_mux_pins(int bus_id)
{
char mux_name[sizeof("i2c2_scl.i2c2_scl")];
/* First I2C bus is not muxable */
if (bus_id == 1)
return;
sprintf(mux_name, "i2c%i_scl.i2c%i_scl", bus_id, bus_id);
omap_mux_init_signal(mux_name, OMAP_PIN_INPUT);
sprintf(mux_name, "i2c%i_sda.i2c%i_sda", bus_id, bus_id);
omap_mux_init_signal(mux_name, OMAP_PIN_INPUT);
}
/**
* omap_i2c_reset - reset the omap i2c module.
* @oh: struct omap_hwmod *
*
* The i2c moudle in omap2, omap3 had a special sequence to reset. The
* sequence is:
* - Disable the I2C.
* - Write to SOFTRESET bit.
* - Enable the I2C.
* - Poll on the RESETDONE bit.
* The sequence is implemented in below function. This is called for 2420,
* 2430 and omap3.
*/
int omap_i2c_reset(struct omap_hwmod *oh)
{
u32 v;
u16 i2c_con;
int c = 0;
if (oh->class->rev == OMAP_I2C_IP_VERSION_2) {
i2c_con = OMAP4_I2C_CON_OFFSET;
} else if (oh->class->rev == OMAP_I2C_IP_VERSION_1) {
i2c_con = OMAP2_I2C_CON_OFFSET;
} else {
WARN(1, "Cannot reset I2C block %s: unsupported revision\n",
oh->name);
return -EINVAL;
}
/* Disable I2C */
v = omap_hwmod_read(oh, i2c_con);
v &= ~I2C_EN;
omap_hwmod_write(v, oh, i2c_con);
/* Write to the SOFTRESET bit */
omap_hwmod_softreset(oh);
/* Enable I2C */
v = omap_hwmod_read(oh, i2c_con);
v |= I2C_EN;
omap_hwmod_write(v, oh, i2c_con);
/* Poll on RESETDONE bit */
omap_test_timeout((omap_hwmod_read(oh,
oh->class->sysc->syss_offs)
& SYSS_RESETDONE_MASK),
MAX_MODULE_SOFTRESET_WAIT, c);
if (c == MAX_MODULE_SOFTRESET_WAIT)
pr_warning("%s: %s: softreset failed (waited %d usec)\n",
__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
else
pr_debug("%s: %s: softreset in %d usec\n", __func__,
oh->name, c);
return 0;
}
static const char name[] = "omap_i2c";
int __init omap_i2c_add_bus(struct omap_i2c_bus_platform_data *i2c_pdata,
int bus_id)
{
int l;
struct omap_hwmod *oh;
struct platform_device *pdev;
char oh_name[MAX_OMAP_I2C_HWMOD_NAME_LEN];
struct omap_i2c_bus_platform_data *pdata;
struct omap_i2c_dev_attr *dev_attr;
omap2_i2c_mux_pins(bus_id);
l = snprintf(oh_name, MAX_OMAP_I2C_HWMOD_NAME_LEN, "i2c%d", bus_id);
WARN(l >= MAX_OMAP_I2C_HWMOD_NAME_LEN,
"String buffer overflow in I2C%d device setup\n", bus_id);
oh = omap_hwmod_lookup(oh_name);
if (!oh) {
pr_err("Could not look up %s\n", oh_name);
return -EEXIST;
}
pdata = i2c_pdata;
/*
* pass the hwmod class's CPU-specific knowledge of I2C IP revision in
* use, and functionality implementation flags, up to the OMAP I2C
* driver via platform data
*/
pdata->rev = oh->class->rev;
dev_attr = (struct omap_i2c_dev_attr *)oh->dev_attr;
pdata->flags = dev_attr->flags;
pdev = omap_device_build(name, bus_id, oh, pdata,
sizeof(struct omap_i2c_bus_platform_data),
NULL, 0, 0);
WARN(IS_ERR(pdev), "Could not build omap_device for %s\n", name);
return PTR_RET(pdev);
}
|
