rtc-bq32k.c
4.43 KB
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
/*
* Driver for TI BQ32000 RTC.
*
* Copyright (C) 2009 Semihalf.
*
* 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.
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/bcd.h>
#define BQ32K_SECONDS 0x00 /* Seconds register address */
#define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */
#define BQ32K_STOP 0x80 /* Oscillator Stop flat */
#define BQ32K_MINUTES 0x01 /* Minutes register address */
#define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */
#define BQ32K_OF 0x80 /* Oscillator Failure flag */
#define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */
#define BQ32K_CENT 0x40 /* Century flag */
#define BQ32K_CENT_EN 0x80 /* Century flag enable bit */
struct bq32k_regs {
uint8_t seconds;
uint8_t minutes;
uint8_t cent_hours;
uint8_t day;
uint8_t date;
uint8_t month;
uint8_t years;
};
static struct i2c_driver bq32k_driver;
static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = &off,
}, {
.addr = client->addr,
.flags = I2C_M_RD,
.len = len,
.buf = data,
}
};
if (i2c_transfer(client->adapter, msgs, 2) == 2)
return 0;
return -EIO;
}
static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
{
struct i2c_client *client = to_i2c_client(dev);
uint8_t buffer[len + 1];
buffer[0] = off;
memcpy(&buffer[1], data, len);
if (i2c_master_send(client, buffer, len + 1) == len + 1)
return 0;
return -EIO;
}
static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct bq32k_regs regs;
int error;
error = bq32k_read(dev, ®s, 0, sizeof(regs));
if (error)
return error;
tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
tm->tm_min = bcd2bin(regs.minutes & BQ32K_SECONDS_MASK);
tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
tm->tm_mday = bcd2bin(regs.date);
tm->tm_wday = bcd2bin(regs.day) - 1;
tm->tm_mon = bcd2bin(regs.month) - 1;
tm->tm_year = bcd2bin(regs.years) +
((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
return rtc_valid_tm(tm);
}
static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct bq32k_regs regs;
regs.seconds = bin2bcd(tm->tm_sec);
regs.minutes = bin2bcd(tm->tm_min);
regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
regs.day = bin2bcd(tm->tm_wday + 1);
regs.date = bin2bcd(tm->tm_mday);
regs.month = bin2bcd(tm->tm_mon + 1);
if (tm->tm_year >= 100) {
regs.cent_hours |= BQ32K_CENT;
regs.years = bin2bcd(tm->tm_year - 100);
} else
regs.years = bin2bcd(tm->tm_year);
return bq32k_write(dev, ®s, 0, sizeof(regs));
}
static const struct rtc_class_ops bq32k_rtc_ops = {
.read_time = bq32k_rtc_read_time,
.set_time = bq32k_rtc_set_time,
};
static int bq32k_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct rtc_device *rtc;
uint8_t reg;
int error;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
/* Check Oscillator Stop flag */
error = bq32k_read(dev, ®, BQ32K_SECONDS, 1);
if (!error && (reg & BQ32K_STOP)) {
dev_warn(dev, "Oscillator was halted. Restarting...\n");
reg &= ~BQ32K_STOP;
error = bq32k_write(dev, ®, BQ32K_SECONDS, 1);
}
if (error)
return error;
/* Check Oscillator Failure flag */
error = bq32k_read(dev, ®, BQ32K_MINUTES, 1);
if (!error && (reg & BQ32K_OF)) {
dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
reg &= ~BQ32K_OF;
error = bq32k_write(dev, ®, BQ32K_MINUTES, 1);
}
if (error)
return error;
rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
&bq32k_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
i2c_set_clientdata(client, rtc);
return 0;
}
static const struct i2c_device_id bq32k_id[] = {
{ "bq32000", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, bq32k_id);
static struct i2c_driver bq32k_driver = {
.driver = {
.name = "bq32k",
.owner = THIS_MODULE,
},
.probe = bq32k_probe,
.id_table = bq32k_id,
};
module_i2c_driver(bq32k_driver);
MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
MODULE_LICENSE("GPL");