diff options
Diffstat (limited to 'drivers/rtc/rtc-rx4581.c')
| -rw-r--r-- | drivers/rtc/rtc-rx4581.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rx4581.c b/drivers/rtc/rtc-rx4581.c new file mode 100644 index 000000000..c092e0452 --- /dev/null +++ b/drivers/rtc/rtc-rx4581.c @@ -0,0 +1,292 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* drivers/rtc/rtc-rx4581.c + * + * written by Torben Hohn <torbenh@linutronix.de> + * + * Based on: + * drivers/rtc/rtc-max6902.c + * + * Copyright (C) 2006 8D Technologies inc. + * Copyright (C) 2004 Compulab Ltd. + * + * Driver for MAX6902 spi RTC + * + * and based on: + * drivers/rtc/rtc-rx8581.c + * + * An I2C driver for the Epson RX8581 RTC + * + * Author: Martyn Welch <martyn.welch@ge.com> + * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. + * + * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) + * Copyright 2005-06 Tower Technologies + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/init.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> +#include <linux/bcd.h> + +#define RX4581_REG_SC 0x00 /* Second in BCD */ +#define RX4581_REG_MN 0x01 /* Minute in BCD */ +#define RX4581_REG_HR 0x02 /* Hour in BCD */ +#define RX4581_REG_DW 0x03 /* Day of Week */ +#define RX4581_REG_DM 0x04 /* Day of Month in BCD */ +#define RX4581_REG_MO 0x05 /* Month in BCD */ +#define RX4581_REG_YR 0x06 /* Year in BCD */ +#define RX4581_REG_RAM 0x07 /* RAM */ +#define RX4581_REG_AMN 0x08 /* Alarm Min in BCD*/ +#define RX4581_REG_AHR 0x09 /* Alarm Hour in BCD */ +#define RX4581_REG_ADM 0x0A +#define RX4581_REG_ADW 0x0A +#define RX4581_REG_TMR0 0x0B +#define RX4581_REG_TMR1 0x0C +#define RX4581_REG_EXT 0x0D /* Extension Register */ +#define RX4581_REG_FLAG 0x0E /* Flag Register */ +#define RX4581_REG_CTRL 0x0F /* Control Register */ + + +/* Flag Register bit definitions */ +#define RX4581_FLAG_UF 0x20 /* Update */ +#define RX4581_FLAG_TF 0x10 /* Timer */ +#define RX4581_FLAG_AF 0x08 /* Alarm */ +#define RX4581_FLAG_VLF 0x02 /* Voltage Low */ + +/* Control Register bit definitions */ +#define RX4581_CTRL_UIE 0x20 /* Update Interrupt Enable */ +#define RX4581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ +#define RX4581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ +#define RX4581_CTRL_STOP 0x02 /* STOP bit */ +#define RX4581_CTRL_RESET 0x01 /* RESET bit */ + +static int rx4581_set_reg(struct device *dev, unsigned char address, + unsigned char data) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[2]; + + /* high nibble must be '0' to write */ + buf[0] = address & 0x0f; + buf[1] = data; + + return spi_write_then_read(spi, buf, 2, NULL, 0); +} + +static int rx4581_get_reg(struct device *dev, unsigned char address, + unsigned char *data) +{ + struct spi_device *spi = to_spi_device(dev); + + /* Set MSB to indicate read */ + *data = address | 0x80; + + return spi_write_then_read(spi, data, 1, data, 1); +} + +/* + * In the routines that deal directly with the rx8581 hardware, we use + * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. + */ +static int rx4581_get_datetime(struct device *dev, struct rtc_time *tm) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char date[7]; + unsigned char data; + int err; + + /* First we ensure that the "update flag" is not set, we read the + * time and date then re-read the "update flag". If the update flag + * has been set, we know that the time has changed during the read so + * we repeat the whole process again. + */ + err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); + if (err != 0) { + dev_err(dev, "Unable to read device flags\n"); + return -EIO; + } + + do { + /* If update flag set, clear it */ + if (data & RX4581_FLAG_UF) { + err = rx4581_set_reg(dev, + RX4581_REG_FLAG, (data & ~RX4581_FLAG_UF)); + if (err != 0) { + dev_err(dev, "Unable to write device " + "flags\n"); + return -EIO; + } + } + + /* Now read time and date */ + date[0] = 0x80; + err = spi_write_then_read(spi, date, 1, date, 7); + if (err < 0) { + dev_err(dev, "Unable to read date\n"); + return -EIO; + } + + /* Check flag register */ + err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); + if (err != 0) { + dev_err(dev, "Unable to read device flags\n"); + return -EIO; + } + } while (data & RX4581_FLAG_UF); + + if (data & RX4581_FLAG_VLF) + dev_info(dev, + "low voltage detected, date/time is not reliable.\n"); + + dev_dbg(dev, + "%s: raw data is sec=%02x, min=%02x, hr=%02x, " + "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", + __func__, + date[0], date[1], date[2], date[3], date[4], date[5], date[6]); + + tm->tm_sec = bcd2bin(date[RX4581_REG_SC] & 0x7F); + tm->tm_min = bcd2bin(date[RX4581_REG_MN] & 0x7F); + tm->tm_hour = bcd2bin(date[RX4581_REG_HR] & 0x3F); /* rtc hr 0-23 */ + tm->tm_wday = ilog2(date[RX4581_REG_DW] & 0x7F); + tm->tm_mday = bcd2bin(date[RX4581_REG_DM] & 0x3F); + tm->tm_mon = bcd2bin(date[RX4581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ + tm->tm_year = bcd2bin(date[RX4581_REG_YR]); + if (tm->tm_year < 70) + tm->tm_year += 100; /* assume we are in 1970...2069 */ + + + dev_dbg(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); + + return 0; +} + +static int rx4581_set_datetime(struct device *dev, struct rtc_time *tm) +{ + struct spi_device *spi = to_spi_device(dev); + int err; + unsigned char buf[8], data; + + dev_dbg(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); + + buf[0] = 0x00; + /* hours, minutes and seconds */ + buf[RX4581_REG_SC+1] = bin2bcd(tm->tm_sec); + buf[RX4581_REG_MN+1] = bin2bcd(tm->tm_min); + buf[RX4581_REG_HR+1] = bin2bcd(tm->tm_hour); + + buf[RX4581_REG_DM+1] = bin2bcd(tm->tm_mday); + + /* month, 1 - 12 */ + buf[RX4581_REG_MO+1] = bin2bcd(tm->tm_mon + 1); + + /* year and century */ + buf[RX4581_REG_YR+1] = bin2bcd(tm->tm_year % 100); + buf[RX4581_REG_DW+1] = (0x1 << tm->tm_wday); + + /* Stop the clock */ + err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); + if (err != 0) { + dev_err(dev, "Unable to read control register\n"); + return -EIO; + } + + err = rx4581_set_reg(dev, RX4581_REG_CTRL, + (data | RX4581_CTRL_STOP)); + if (err != 0) { + dev_err(dev, "Unable to write control register\n"); + return -EIO; + } + + /* write register's data */ + err = spi_write_then_read(spi, buf, 8, NULL, 0); + if (err != 0) { + dev_err(dev, "Unable to write to date registers\n"); + return -EIO; + } + + /* get VLF and clear it */ + err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data); + if (err != 0) { + dev_err(dev, "Unable to read flag register\n"); + return -EIO; + } + + err = rx4581_set_reg(dev, RX4581_REG_FLAG, + (data & ~(RX4581_FLAG_VLF))); + if (err != 0) { + dev_err(dev, "Unable to write flag register\n"); + return -EIO; + } + + /* Restart the clock */ + err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data); + if (err != 0) { + dev_err(dev, "Unable to read control register\n"); + return -EIO; + } + + err = rx4581_set_reg(dev, RX4581_REG_CTRL, + (data & ~(RX4581_CTRL_STOP))); + if (err != 0) { + dev_err(dev, "Unable to write control register\n"); + return -EIO; + } + + return 0; +} + +static const struct rtc_class_ops rx4581_rtc_ops = { + .read_time = rx4581_get_datetime, + .set_time = rx4581_set_datetime, +}; + +static int rx4581_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + unsigned char tmp; + int res; + + res = rx4581_get_reg(&spi->dev, RX4581_REG_SC, &tmp); + if (res != 0) + return res; + + rtc = devm_rtc_device_register(&spi->dev, "rx4581", + &rx4581_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + spi_set_drvdata(spi, rtc); + return 0; +} + +static const struct spi_device_id rx4581_id[] = { + { "rx4581", 0 }, + { } +}; +MODULE_DEVICE_TABLE(spi, rx4581_id); + +static struct spi_driver rx4581_driver = { + .driver = { + .name = "rtc-rx4581", + }, + .probe = rx4581_probe, + .id_table = rx4581_id, +}; + +module_spi_driver(rx4581_driver); + +MODULE_DESCRIPTION("rx4581 spi RTC driver"); +MODULE_AUTHOR("Torben Hohn"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("spi:rtc-rx4581"); |