diff options
Diffstat (limited to 'drivers/rtc/rtc-pcf85063.c')
| -rw-r--r-- | drivers/rtc/rtc-pcf85063.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c new file mode 100644 index 000000000000..6a12bf62c504 --- /dev/null +++ b/drivers/rtc/rtc-pcf85063.c @@ -0,0 +1,204 @@ +/* + * An I2C driver for the PCF85063 RTC + * Copyright 2014 Rose Technology + * + * Author: Søren Andersen <san@rosetechnology.dk> + * Maintainers: http://www.nslu2-linux.org/ + * + * based on the other drivers in this same directory. + * + * 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/i2c.h> +#include <linux/bcd.h> +#include <linux/rtc.h> +#include <linux/module.h> + +#define DRV_VERSION "0.0.1" + +#define PCF85063_REG_CTRL1 0x00 /* status */ +#define PCF85063_REG_CTRL2 0x01 + +#define PCF85063_REG_SC 0x04 /* datetime */ +#define PCF85063_REG_MN 0x05 +#define PCF85063_REG_HR 0x06 +#define PCF85063_REG_DM 0x07 +#define PCF85063_REG_DW 0x08 +#define PCF85063_REG_MO 0x09 +#define PCF85063_REG_YR 0x0A + +#define PCF85063_MO_C 0x80 /* century */ + +static struct i2c_driver pcf85063_driver; + +struct pcf85063 { + struct rtc_device *rtc; + int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ + int voltage_low; /* indicates if a low_voltage was detected */ +}; + +/* + * In the routines that deal directly with the pcf85063 hardware, we use + * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. + */ +static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm) +{ + struct pcf85063 *pcf85063 = i2c_get_clientdata(client); + unsigned char buf[13] = { PCF85063_REG_CTRL1 }; + struct i2c_msg msgs[] = { + {/* setup read ptr */ + .addr = client->addr, + .len = 1, + .buf = buf + }, + {/* read status + date */ + .addr = client->addr, + .flags = I2C_M_RD, + .len = 13, + .buf = buf + }, + }; + + /* read registers */ + if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { + dev_err(&client->dev, "%s: read error\n", __func__); + return -EIO; + } + + tm->tm_sec = bcd2bin(buf[PCF85063_REG_SC] & 0x7F); + tm->tm_min = bcd2bin(buf[PCF85063_REG_MN] & 0x7F); + tm->tm_hour = bcd2bin(buf[PCF85063_REG_HR] & 0x3F); /* rtc hr 0-23 */ + tm->tm_mday = bcd2bin(buf[PCF85063_REG_DM] & 0x3F); + tm->tm_wday = buf[PCF85063_REG_DW] & 0x07; + tm->tm_mon = bcd2bin(buf[PCF85063_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ + tm->tm_year = bcd2bin(buf[PCF85063_REG_YR]); + if (tm->tm_year < 70) + tm->tm_year += 100; /* assume we are in 1970...2069 */ + /* detect the polarity heuristically. see note above. */ + pcf85063->c_polarity = (buf[PCF85063_REG_MO] & PCF85063_MO_C) ? + (tm->tm_year >= 100) : (tm->tm_year < 100); + + /* the clock can give out invalid datetime, but we cannot return + * -EINVAL otherwise hwclock will refuse to set the time on bootup. + */ + if (rtc_valid_tm(tm) < 0) + dev_err(&client->dev, "retrieved date/time is not valid.\n"); + + return 0; +} + +static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm) +{ + int i = 0, err = 0; + unsigned char buf[11]; + + /* Control & status */ + buf[PCF85063_REG_CTRL1] = 0; + buf[PCF85063_REG_CTRL2] = 5; + + /* hours, minutes and seconds */ + buf[PCF85063_REG_SC] = bin2bcd(tm->tm_sec) & 0x7F; + + buf[PCF85063_REG_MN] = bin2bcd(tm->tm_min); + buf[PCF85063_REG_HR] = bin2bcd(tm->tm_hour); + + /* Day of month, 1 - 31 */ + buf[PCF85063_REG_DM] = bin2bcd(tm->tm_mday); + + /* Day, 0 - 6 */ + buf[PCF85063_REG_DW] = tm->tm_wday & 0x07; + + /* month, 1 - 12 */ + buf[PCF85063_REG_MO] = bin2bcd(tm->tm_mon + 1); + + /* year and century */ + buf[PCF85063_REG_YR] = bin2bcd(tm->tm_year % 100); + + /* write register's data */ + for (i = 0; i < sizeof(buf); i++) { + unsigned char data[2] = { i, buf[i] }; + + err = i2c_master_send(client, data, sizeof(data)); + if (err != sizeof(data)) { + dev_err(&client->dev, "%s: err=%d addr=%02x, data=%02x\n", + __func__, err, data[0], data[1]); + return -EIO; + } + } + + return 0; +} + +static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + return pcf85063_get_datetime(to_i2c_client(dev), tm); +} + +static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + return pcf85063_set_datetime(to_i2c_client(dev), tm); +} + +static const struct rtc_class_ops pcf85063_rtc_ops = { + .read_time = pcf85063_rtc_read_time, + .set_time = pcf85063_rtc_set_time +}; + +static int pcf85063_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct pcf85063 *pcf85063; + + dev_dbg(&client->dev, "%s\n", __func__); + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -ENODEV; + + pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063), + GFP_KERNEL); + if (!pcf85063) + return -ENOMEM; + + dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); + + i2c_set_clientdata(client, pcf85063); + + pcf85063->rtc = devm_rtc_device_register(&client->dev, + pcf85063_driver.driver.name, + &pcf85063_rtc_ops, THIS_MODULE); + + return PTR_ERR_OR_ZERO(pcf85063->rtc); +} + +static const struct i2c_device_id pcf85063_id[] = { + { "pcf85063", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, pcf85063_id); + +#ifdef CONFIG_OF +static const struct of_device_id pcf85063_of_match[] = { + { .compatible = "nxp,pcf85063" }, + {} +}; +MODULE_DEVICE_TABLE(of, pcf85063_of_match); +#endif + +static struct i2c_driver pcf85063_driver = { + .driver = { + .name = "rtc-pcf85063", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(pcf85063_of_match), + }, + .probe = pcf85063_probe, + .id_table = pcf85063_id, +}; + +module_i2c_driver(pcf85063_driver); + +MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>"); +MODULE_DESCRIPTION("PCF85063 RTC driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); |