diff options
Diffstat (limited to 'drivers/rtc/rtc-pcf2127.c')
| -rw-r--r-- | drivers/rtc/rtc-pcf2127.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c new file mode 100644 index 0000000..205b9f7 --- /dev/null +++ b/drivers/rtc/rtc-pcf2127.c @@ -0,0 +1,241 @@ +/* + * An I2C driver for the NXP PCF2127 RTC + * Copyright 2013 Til-Technologies + * + * Author: Renaud Cerrato <r.cerrato@til-technologies.fr> + * + * based on the other drivers in this same directory. + * + * http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf + * + * 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/slab.h> +#include <linux/module.h> +#include <linux/of.h> + +#define DRV_VERSION "0.0.1" + +#define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */ +#define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */ +#define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */ +#define PCF2127_REG_SC (0x03) /* datetime */ +#define PCF2127_REG_MN (0x04) +#define PCF2127_REG_HR (0x05) +#define PCF2127_REG_DM (0x06) +#define PCF2127_REG_DW (0x07) +#define PCF2127_REG_MO (0x08) +#define PCF2127_REG_YR (0x09) + +static struct i2c_driver pcf2127_driver; + +struct pcf2127 { + struct rtc_device *rtc; + int voltage_low; /* indicates if a low_voltage was detected */ +}; + +/* + * In the routines that deal directly with the pcf2127 hardware, we use + * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. + */ +static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) +{ + struct pcf2127 *pcf2127 = i2c_get_clientdata(client); + unsigned char buf[10] = { PCF2127_REG_CTRL1 }; + + /* read registers */ + if (i2c_master_send(client, buf, 1) != 1 || + i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) { + dev_err(&client->dev, "%s: read error\n", __func__); + return -EIO; + } + + if (buf[PCF2127_REG_CTRL3] & 0x04) { + pcf2127->voltage_low = 1; + dev_info(&client->dev, + "low voltage detected, date/time is not reliable.\n"); + } + + dev_dbg(&client->dev, + "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, " + "sec=%02x, min=%02x, hr=%02x, " + "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", + __func__, + buf[0], buf[1], buf[2], + buf[3], buf[4], buf[5], + buf[6], buf[7], buf[8], buf[9]); + + + tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F); + tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F); + tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */ + tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F); + tm->tm_wday = buf[PCF2127_REG_DW] & 0x07; + tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ + tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]); + if (tm->tm_year < 70) + tm->tm_year += 100; /* assume we are in 1970...2069 */ + + dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " + "mday=%d, mon=%d, year=%d, wday=%d\n", + __func__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); + + /* 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 pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) +{ + unsigned char buf[8]; + int i = 0, err; + + dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " + "mday=%d, mon=%d, year=%d, wday=%d\n", + __func__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); + + /* start register address */ + buf[i++] = PCF2127_REG_SC; + + /* hours, minutes and seconds */ + buf[i++] = bin2bcd(tm->tm_sec); + buf[i++] = bin2bcd(tm->tm_min); + buf[i++] = bin2bcd(tm->tm_hour); + buf[i++] = bin2bcd(tm->tm_mday); + buf[i++] = tm->tm_wday & 0x07; + + /* month, 1 - 12 */ + buf[i++] = bin2bcd(tm->tm_mon + 1); + + /* year */ + buf[i++] = bin2bcd(tm->tm_year % 100); + + /* write register's data */ + err = i2c_master_send(client, buf, i); + if (err != i) { + dev_err(&client->dev, + "%s: err=%d", __func__, err); + return -EIO; + } + + return 0; +} + +#ifdef CONFIG_RTC_INTF_DEV +static int pcf2127_rtc_ioctl(struct device *dev, + unsigned int cmd, unsigned long arg) +{ + struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev)); + + switch (cmd) { + case RTC_VL_READ: + if (pcf2127->voltage_low) + dev_info(dev, "low voltage detected, date/time is not reliable.\n"); + + if (copy_to_user((void __user *)arg, &pcf2127->voltage_low, + sizeof(int))) + return -EFAULT; + return 0; + default: + return -ENOIOCTLCMD; + } +} +#else +#define pcf2127_rtc_ioctl NULL +#endif + +static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + return pcf2127_get_datetime(to_i2c_client(dev), tm); +} + +static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + return pcf2127_set_datetime(to_i2c_client(dev), tm); +} + +static const struct rtc_class_ops pcf2127_rtc_ops = { + .ioctl = pcf2127_rtc_ioctl, + .read_time = pcf2127_rtc_read_time, + .set_time = pcf2127_rtc_set_time, +}; + +static int pcf2127_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct pcf2127 *pcf2127; + + dev_dbg(&client->dev, "%s\n", __func__); + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -ENODEV; + + pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127), + GFP_KERNEL); + if (!pcf2127) + return -ENOMEM; + + dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); + + i2c_set_clientdata(client, pcf2127); + + pcf2127->rtc = devm_rtc_device_register(&client->dev, + pcf2127_driver.driver.name, + &pcf2127_rtc_ops, THIS_MODULE); + + if (IS_ERR(pcf2127->rtc)) + return PTR_ERR(pcf2127->rtc); + + return 0; +} + +static int pcf2127_remove(struct i2c_client *client) +{ + return 0; +} + +static const struct i2c_device_id pcf2127_id[] = { + { "pcf2127", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, pcf2127_id); + +#ifdef CONFIG_OF +static const struct of_device_id pcf2127_of_match[] = { + { .compatible = "nxp,pcf2127" }, + {} +}; +MODULE_DEVICE_TABLE(of, pcf2127_of_match); +#endif + +static struct i2c_driver pcf2127_driver = { + .driver = { + .name = "rtc-pcf2127", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(pcf2127_of_match), + }, + .probe = pcf2127_probe, + .remove = pcf2127_remove, + .id_table = pcf2127_id, +}; + +module_i2c_driver(pcf2127_driver); + +MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>"); +MODULE_DESCRIPTION("NXP PCF2127 RTC driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); |
