2 * An I2C driver for the NXP PCF2127 RTC
3 * Copyright 2013 Til-Technologies
5 * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
7 * based on the other drivers in this same directory.
9 * http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
16 #include <linux/i2c.h>
17 #include <linux/bcd.h>
18 #include <linux/rtc.h>
19 #include <linux/slab.h>
20 #include <linux/module.h>
23 #define DRV_VERSION "0.0.1"
25 #define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */
26 #define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */
27 #define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */
28 #define PCF2127_REG_SC (0x03) /* datetime */
29 #define PCF2127_REG_MN (0x04)
30 #define PCF2127_REG_HR (0x05)
31 #define PCF2127_REG_DM (0x06)
32 #define PCF2127_REG_DW (0x07)
33 #define PCF2127_REG_MO (0x08)
34 #define PCF2127_REG_YR (0x09)
36 #define PCF2127_OSF BIT(7) /* Oscillator Fail flag */
38 static struct i2c_driver pcf2127_driver
;
41 struct rtc_device
*rtc
;
42 int voltage_low
; /* indicates if a low_voltage was detected */
43 int oscillator_failed
; /* OSF was detected and date is unreliable */
47 * In the routines that deal directly with the pcf2127 hardware, we use
48 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
50 static int pcf2127_get_datetime(struct i2c_client
*client
, struct rtc_time
*tm
)
52 struct pcf2127
*pcf2127
= i2c_get_clientdata(client
);
53 unsigned char buf
[10] = { PCF2127_REG_CTRL1
};
56 if (i2c_master_send(client
, buf
, 1) != 1 ||
57 i2c_master_recv(client
, buf
, sizeof(buf
)) != sizeof(buf
)) {
58 dev_err(&client
->dev
, "%s: read error\n", __func__
);
62 if (buf
[PCF2127_REG_CTRL3
] & 0x04) {
63 pcf2127
->voltage_low
= 1;
64 dev_info(&client
->dev
,
65 "low voltage detected, check/replace RTC battery.\n");
68 if (buf
[PCF2127_REG_SC
] & PCF2127_OSF
) {
70 * no need clear the flag here,
71 * it will be cleared once the new date is saved
73 pcf2127
->oscillator_failed
= 1;
74 dev_warn(&client
->dev
,
75 "oscillator stop detected, date/time is not reliable\n");
80 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "
81 "sec=%02x, min=%02x, hr=%02x, "
82 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
84 buf
[0], buf
[1], buf
[2],
85 buf
[3], buf
[4], buf
[5],
86 buf
[6], buf
[7], buf
[8], buf
[9]);
89 tm
->tm_sec
= bcd2bin(buf
[PCF2127_REG_SC
] & 0x7F);
90 tm
->tm_min
= bcd2bin(buf
[PCF2127_REG_MN
] & 0x7F);
91 tm
->tm_hour
= bcd2bin(buf
[PCF2127_REG_HR
] & 0x3F); /* rtc hr 0-23 */
92 tm
->tm_mday
= bcd2bin(buf
[PCF2127_REG_DM
] & 0x3F);
93 tm
->tm_wday
= buf
[PCF2127_REG_DW
] & 0x07;
94 tm
->tm_mon
= bcd2bin(buf
[PCF2127_REG_MO
] & 0x1F) - 1; /* rtc mn 1-12 */
95 tm
->tm_year
= bcd2bin(buf
[PCF2127_REG_YR
]);
97 tm
->tm_year
+= 100; /* assume we are in 1970...2069 */
99 dev_dbg(&client
->dev
, "%s: tm is secs=%d, mins=%d, hours=%d, "
100 "mday=%d, mon=%d, year=%d, wday=%d\n",
102 tm
->tm_sec
, tm
->tm_min
, tm
->tm_hour
,
103 tm
->tm_mday
, tm
->tm_mon
, tm
->tm_year
, tm
->tm_wday
);
105 return rtc_valid_tm(tm
);
108 static int pcf2127_set_datetime(struct i2c_client
*client
, struct rtc_time
*tm
)
110 struct pcf2127
*pcf2127
= i2c_get_clientdata(client
);
111 unsigned char buf
[8];
114 dev_dbg(&client
->dev
, "%s: secs=%d, mins=%d, hours=%d, "
115 "mday=%d, mon=%d, year=%d, wday=%d\n",
117 tm
->tm_sec
, tm
->tm_min
, tm
->tm_hour
,
118 tm
->tm_mday
, tm
->tm_mon
, tm
->tm_year
, tm
->tm_wday
);
120 /* start register address */
121 buf
[i
++] = PCF2127_REG_SC
;
123 /* hours, minutes and seconds */
124 buf
[i
++] = bin2bcd(tm
->tm_sec
); /* this will also clear OSF flag */
125 buf
[i
++] = bin2bcd(tm
->tm_min
);
126 buf
[i
++] = bin2bcd(tm
->tm_hour
);
127 buf
[i
++] = bin2bcd(tm
->tm_mday
);
128 buf
[i
++] = tm
->tm_wday
& 0x07;
131 buf
[i
++] = bin2bcd(tm
->tm_mon
+ 1);
134 buf
[i
++] = bin2bcd(tm
->tm_year
% 100);
136 /* write register's data */
137 err
= i2c_master_send(client
, buf
, i
);
139 dev_err(&client
->dev
,
140 "%s: err=%d", __func__
, err
);
144 /* clear OSF flag in client data */
145 pcf2127
->oscillator_failed
= 0;
150 #ifdef CONFIG_RTC_INTF_DEV
151 static int pcf2127_rtc_ioctl(struct device
*dev
,
152 unsigned int cmd
, unsigned long arg
)
154 struct pcf2127
*pcf2127
= i2c_get_clientdata(to_i2c_client(dev
));
158 if (pcf2127
->voltage_low
)
159 dev_info(dev
, "low voltage detected, check/replace battery\n");
160 if (pcf2127
->oscillator_failed
)
161 dev_info(dev
, "oscillator stop detected, date/time is not reliable\n");
163 if (copy_to_user((void __user
*)arg
, &pcf2127
->voltage_low
,
172 #define pcf2127_rtc_ioctl NULL
175 static int pcf2127_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
177 return pcf2127_get_datetime(to_i2c_client(dev
), tm
);
180 static int pcf2127_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
182 return pcf2127_set_datetime(to_i2c_client(dev
), tm
);
185 static const struct rtc_class_ops pcf2127_rtc_ops
= {
186 .ioctl
= pcf2127_rtc_ioctl
,
187 .read_time
= pcf2127_rtc_read_time
,
188 .set_time
= pcf2127_rtc_set_time
,
191 static int pcf2127_probe(struct i2c_client
*client
,
192 const struct i2c_device_id
*id
)
194 struct pcf2127
*pcf2127
;
196 dev_dbg(&client
->dev
, "%s\n", __func__
);
198 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_I2C
))
201 pcf2127
= devm_kzalloc(&client
->dev
, sizeof(struct pcf2127
),
206 dev_info(&client
->dev
, "chip found, driver version " DRV_VERSION
"\n");
208 i2c_set_clientdata(client
, pcf2127
);
210 pcf2127
->rtc
= devm_rtc_device_register(&client
->dev
,
211 pcf2127_driver
.driver
.name
,
212 &pcf2127_rtc_ops
, THIS_MODULE
);
214 return PTR_ERR_OR_ZERO(pcf2127
->rtc
);
217 static const struct i2c_device_id pcf2127_id
[] = {
221 MODULE_DEVICE_TABLE(i2c
, pcf2127_id
);
224 static const struct of_device_id pcf2127_of_match
[] = {
225 { .compatible
= "nxp,pcf2127" },
228 MODULE_DEVICE_TABLE(of
, pcf2127_of_match
);
231 static struct i2c_driver pcf2127_driver
= {
233 .name
= "rtc-pcf2127",
234 .of_match_table
= of_match_ptr(pcf2127_of_match
),
236 .probe
= pcf2127_probe
,
237 .id_table
= pcf2127_id
,
240 module_i2c_driver(pcf2127_driver
);
242 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
243 MODULE_DESCRIPTION("NXP PCF2127 RTC driver");
244 MODULE_LICENSE("GPL");
245 MODULE_VERSION(DRV_VERSION
);