2 * Driver for TI BQ32000 RTC.
4 * Copyright (C) 2009 Semihalf.
5 * Copyright (C) 2014 Pavel Machek <pavel@denx.de>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * You can get hardware description at
12 * http://www.ti.com/lit/ds/symlink/bq32000.pdf
15 #include <linux/module.h>
16 #include <linux/i2c.h>
17 #include <linux/rtc.h>
18 #include <linux/init.h>
19 #include <linux/errno.h>
20 #include <linux/bcd.h>
22 #define BQ32K_SECONDS 0x00 /* Seconds register address */
23 #define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */
24 #define BQ32K_STOP 0x80 /* Oscillator Stop flat */
26 #define BQ32K_MINUTES 0x01 /* Minutes register address */
27 #define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */
28 #define BQ32K_OF 0x80 /* Oscillator Failure flag */
30 #define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */
31 #define BQ32K_CENT 0x40 /* Century flag */
32 #define BQ32K_CENT_EN 0x80 /* Century flag enable bit */
34 #define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */
35 #define BQ32K_TCH2 0x08 /* Trickle charge enable */
36 #define BQ32K_CFG2 0x09 /* Trickle charger control */
48 static struct i2c_driver bq32k_driver
;
50 static int bq32k_read(struct device
*dev
, void *data
, uint8_t off
, uint8_t len
)
52 struct i2c_client
*client
= to_i2c_client(dev
);
53 struct i2c_msg msgs
[] = {
67 if (i2c_transfer(client
->adapter
, msgs
, 2) == 2)
73 static int bq32k_write(struct device
*dev
, void *data
, uint8_t off
, uint8_t len
)
75 struct i2c_client
*client
= to_i2c_client(dev
);
76 uint8_t buffer
[len
+ 1];
79 memcpy(&buffer
[1], data
, len
);
81 if (i2c_master_send(client
, buffer
, len
+ 1) == len
+ 1)
87 static int bq32k_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
89 struct bq32k_regs regs
;
92 error
= bq32k_read(dev
, ®s
, 0, sizeof(regs
));
96 tm
->tm_sec
= bcd2bin(regs
.seconds
& BQ32K_SECONDS_MASK
);
97 tm
->tm_min
= bcd2bin(regs
.minutes
& BQ32K_SECONDS_MASK
);
98 tm
->tm_hour
= bcd2bin(regs
.cent_hours
& BQ32K_HOURS_MASK
);
99 tm
->tm_mday
= bcd2bin(regs
.date
);
100 tm
->tm_wday
= bcd2bin(regs
.day
) - 1;
101 tm
->tm_mon
= bcd2bin(regs
.month
) - 1;
102 tm
->tm_year
= bcd2bin(regs
.years
) +
103 ((regs
.cent_hours
& BQ32K_CENT
) ? 100 : 0);
105 return rtc_valid_tm(tm
);
108 static int bq32k_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
110 struct bq32k_regs regs
;
112 regs
.seconds
= bin2bcd(tm
->tm_sec
);
113 regs
.minutes
= bin2bcd(tm
->tm_min
);
114 regs
.cent_hours
= bin2bcd(tm
->tm_hour
) | BQ32K_CENT_EN
;
115 regs
.day
= bin2bcd(tm
->tm_wday
+ 1);
116 regs
.date
= bin2bcd(tm
->tm_mday
);
117 regs
.month
= bin2bcd(tm
->tm_mon
+ 1);
119 if (tm
->tm_year
>= 100) {
120 regs
.cent_hours
|= BQ32K_CENT
;
121 regs
.years
= bin2bcd(tm
->tm_year
- 100);
123 regs
.years
= bin2bcd(tm
->tm_year
);
125 return bq32k_write(dev
, ®s
, 0, sizeof(regs
));
128 static const struct rtc_class_ops bq32k_rtc_ops
= {
129 .read_time
= bq32k_rtc_read_time
,
130 .set_time
= bq32k_rtc_set_time
,
133 static int trickle_charger_of_init(struct device
*dev
, struct device_node
*node
)
139 if (of_property_read_u32(node
, "trickle-resistor-ohms" , &ohms
))
145 * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
146 * over diode and 940ohm resistor)
149 if (of_property_read_bool(node
, "trickle-diode-disable")) {
150 dev_err(dev
, "diode and resistor mismatch\n");
159 if (!of_property_read_bool(node
, "trickle-diode-disable")) {
160 dev_err(dev
, "bq32k: diode and resistor mismatch\n");
167 dev_err(dev
, "invalid resistor value (%d)\n", ohms
);
171 error
= bq32k_write(dev
, ®
, BQ32K_CFG2
, 1);
176 error
= bq32k_write(dev
, ®
, BQ32K_TCH2
, 1);
180 dev_info(dev
, "Enabled trickle RTC battery charge.\n");
184 static int bq32k_probe(struct i2c_client
*client
,
185 const struct i2c_device_id
*id
)
187 struct device
*dev
= &client
->dev
;
188 struct rtc_device
*rtc
;
192 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_I2C
))
195 /* Check Oscillator Stop flag */
196 error
= bq32k_read(dev
, ®
, BQ32K_SECONDS
, 1);
197 if (!error
&& (reg
& BQ32K_STOP
)) {
198 dev_warn(dev
, "Oscillator was halted. Restarting...\n");
200 error
= bq32k_write(dev
, ®
, BQ32K_SECONDS
, 1);
205 /* Check Oscillator Failure flag */
206 error
= bq32k_read(dev
, ®
, BQ32K_MINUTES
, 1);
207 if (!error
&& (reg
& BQ32K_OF
)) {
208 dev_warn(dev
, "Oscillator Failure. Check RTC battery.\n");
210 error
= bq32k_write(dev
, ®
, BQ32K_MINUTES
, 1);
215 if (client
->dev
.of_node
)
216 trickle_charger_of_init(dev
, client
->dev
.of_node
);
218 rtc
= devm_rtc_device_register(&client
->dev
, bq32k_driver
.driver
.name
,
219 &bq32k_rtc_ops
, THIS_MODULE
);
223 i2c_set_clientdata(client
, rtc
);
228 static const struct i2c_device_id bq32k_id
[] = {
232 MODULE_DEVICE_TABLE(i2c
, bq32k_id
);
234 static struct i2c_driver bq32k_driver
= {
238 .probe
= bq32k_probe
,
239 .id_table
= bq32k_id
,
242 module_i2c_driver(bq32k_driver
);
244 MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
245 MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
246 MODULE_LICENSE("GPL");