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![Piotr Ziecik](/assets/img/avatar_default.png)
This patch adds basic support for Texas Instruments BQ32000 I2C RTC. Only time reading/writing is implemented. Advanced features, such as trickle charger and crystal calibration are not supported. Signed-off-by: Piotr Ziecik <kosmo@semihalf.com> Signed-off-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
204 lines
4.8 KiB
C
204 lines
4.8 KiB
C
/*
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* Driver for TI BQ32000 RTC.
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*
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* Copyright (C) 2009 Semihalf.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/rtc.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/bcd.h>
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#define BQ32K_SECONDS 0x00 /* Seconds register address */
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#define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */
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#define BQ32K_STOP 0x80 /* Oscillator Stop flat */
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#define BQ32K_MINUTES 0x01 /* Minutes register address */
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#define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */
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#define BQ32K_OF 0x80 /* Oscillator Failure flag */
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#define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */
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#define BQ32K_CENT 0x40 /* Century flag */
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#define BQ32K_CENT_EN 0x80 /* Century flag enable bit */
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struct bq32k_regs {
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uint8_t seconds;
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uint8_t minutes;
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uint8_t cent_hours;
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uint8_t day;
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uint8_t date;
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uint8_t month;
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uint8_t years;
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};
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static struct i2c_driver bq32k_driver;
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static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct i2c_msg msgs[] = {
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{
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.addr = client->addr,
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.flags = 0,
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.len = 1,
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.buf = &off,
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}, {
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.addr = client->addr,
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.flags = I2C_M_RD,
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.len = len,
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.buf = data,
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}
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};
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if (i2c_transfer(client->adapter, msgs, 2) == 2)
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return 0;
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return -EIO;
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}
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static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
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{
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struct i2c_client *client = to_i2c_client(dev);
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uint8_t buffer[len + 1];
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buffer[0] = off;
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memcpy(&buffer[1], data, len);
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if (i2c_master_send(client, buffer, len + 1) == len + 1)
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return 0;
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return -EIO;
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}
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static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct bq32k_regs regs;
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int error;
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error = bq32k_read(dev, ®s, 0, sizeof(regs));
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if (error)
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return error;
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tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
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tm->tm_min = bcd2bin(regs.minutes & BQ32K_SECONDS_MASK);
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tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
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tm->tm_mday = bcd2bin(regs.date);
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tm->tm_wday = bcd2bin(regs.day) - 1;
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tm->tm_mon = bcd2bin(regs.month) - 1;
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tm->tm_year = bcd2bin(regs.years) +
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((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
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return rtc_valid_tm(tm);
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}
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static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct bq32k_regs regs;
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regs.seconds = bin2bcd(tm->tm_sec);
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regs.minutes = bin2bcd(tm->tm_min);
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regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
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regs.day = bin2bcd(tm->tm_wday + 1);
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regs.date = bin2bcd(tm->tm_mday);
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regs.month = bin2bcd(tm->tm_mon + 1);
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if (tm->tm_year >= 100) {
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regs.cent_hours |= BQ32K_CENT;
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regs.years = bin2bcd(tm->tm_year - 100);
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} else
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regs.years = bin2bcd(tm->tm_year);
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return bq32k_write(dev, ®s, 0, sizeof(regs));
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}
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static const struct rtc_class_ops bq32k_rtc_ops = {
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.read_time = bq32k_rtc_read_time,
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.set_time = bq32k_rtc_set_time,
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};
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static int bq32k_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct rtc_device *rtc;
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uint8_t reg;
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int error;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -ENODEV;
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/* Check Oscillator Stop flag */
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error = bq32k_read(dev, ®, BQ32K_SECONDS, 1);
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if (!error && (reg & BQ32K_STOP)) {
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dev_warn(dev, "Oscillator was halted. Restarting...\n");
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reg &= ~BQ32K_STOP;
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error = bq32k_write(dev, ®, BQ32K_SECONDS, 1);
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}
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if (error)
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return error;
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/* Check Oscillator Failure flag */
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error = bq32k_read(dev, ®, BQ32K_MINUTES, 1);
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if (!error && (reg & BQ32K_OF)) {
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dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
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reg &= ~BQ32K_OF;
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error = bq32k_write(dev, ®, BQ32K_MINUTES, 1);
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}
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if (error)
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return error;
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rtc = rtc_device_register(bq32k_driver.driver.name, &client->dev,
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&bq32k_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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i2c_set_clientdata(client, rtc);
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return 0;
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}
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static int __devexit bq32k_remove(struct i2c_client *client)
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{
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struct rtc_device *rtc = i2c_get_clientdata(client);
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rtc_device_unregister(rtc);
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return 0;
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}
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static const struct i2c_device_id bq32k_id[] = {
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{ "bq32000", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, bq32k_id);
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static struct i2c_driver bq32k_driver = {
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.driver = {
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.name = "bq32k",
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.owner = THIS_MODULE,
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},
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.probe = bq32k_probe,
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.remove = __devexit_p(bq32k_remove),
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.id_table = bq32k_id,
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};
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static __init int bq32k_init(void)
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{
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return i2c_add_driver(&bq32k_driver);
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}
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module_init(bq32k_init);
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static __exit void bq32k_exit(void)
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{
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i2c_del_driver(&bq32k_driver);
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}
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module_exit(bq32k_exit);
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MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
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MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
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MODULE_LICENSE("GPL");
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