diff options
Diffstat (limited to 'drivers/rtc/rtc-r9701.c')
| -rw-r--r-- | drivers/rtc/rtc-r9701.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-r9701.c b/drivers/rtc/rtc-r9701.c new file mode 100644 index 00000000000..926e8fda83c --- /dev/null +++ b/drivers/rtc/rtc-r9701.c @@ -0,0 +1,195 @@ +/* drivers/rtc/rtc-r9701.c + * + * Driver for Epson RTC-9701JE + * + * Copyright (C) 2008 Magnus Damm + * + * Based on drivers/rtc/rtc-max6902.c + * + * Copyright (C) 2006 8D Technologies inc. + * Copyright (C) 2004 Compulab Ltd. + * + * 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/module.h> +#include <linux/version.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/device.h> +#include <linux/init.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> +#include <linux/bcd.h> +#include <linux/delay.h> +#include <linux/bitops.h> + +#define RSECCNT 0x00 /* Second Counter */ +#define RMINCNT 0x01 /* Minute Counter */ +#define RHRCNT 0x02 /* Hour Counter */ +#define RWKCNT 0x03 /* Week Counter */ +#define RDAYCNT 0x04 /* Day Counter */ +#define RMONCNT 0x05 /* Month Counter */ +#define RYRCNT 0x06 /* Year Counter */ +#define R100CNT 0x07 /* Y100 Counter */ +#define RMINAR 0x08 /* Minute Alarm */ +#define RHRAR 0x09 /* Hour Alarm */ +#define RWKAR 0x0a /* Week/Day Alarm */ +#define RTIMCNT 0x0c /* Interval Timer */ +#define REXT 0x0d /* Extension Register */ +#define RFLAG 0x0e /* RTC Flag Register */ +#define RCR 0x0f /* RTC Control Register */ + +static int write_reg(struct device *dev, int address, unsigned char data) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[2]; + + buf[0] = address & 0x7f; + buf[1] = data; + + return spi_write(spi, buf, ARRAY_SIZE(buf)); +} + +static int read_regs(struct device *dev, unsigned char *regs, int no_regs) +{ + struct spi_device *spi = to_spi_device(dev); + u8 txbuf[1], rxbuf[1]; + int k, ret; + + ret = 0; + + for (k = 0; ret == 0 && k < no_regs; k++) { + txbuf[0] = 0x80 | regs[k]; + ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); + regs[k] = rxbuf[0]; + } + + return ret; +} + +static int r9701_get_datetime(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned long time; + int ret; + unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT, + RDAYCNT, RMONCNT, RYRCNT }; + + ret = read_regs(&spi->dev, buf, ARRAY_SIZE(buf)); + if (ret) + return ret; + + memset(dt, 0, sizeof(*dt)); + + dt->tm_sec = BCD2BIN(buf[0]); /* RSECCNT */ + dt->tm_min = BCD2BIN(buf[1]); /* RMINCNT */ + dt->tm_hour = BCD2BIN(buf[2]); /* RHRCNT */ + + dt->tm_mday = BCD2BIN(buf[3]); /* RDAYCNT */ + dt->tm_mon = BCD2BIN(buf[4]) - 1; /* RMONCNT */ + dt->tm_year = BCD2BIN(buf[5]) + 100; /* RYRCNT */ + + /* the rtc device may contain illegal values on power up + * according to the data sheet. make sure they are valid. + */ + + ret = rtc_valid_tm(dt); + if (ret) + return ret; + + /* don't bother with yday, wday and isdst. + * let the rtc core calculate them for us. + */ + + rtc_tm_to_time(dt, &time); + rtc_time_to_tm(time, dt); + return 0; +} + +static int r9701_set_datetime(struct device *dev, struct rtc_time *dt) +{ + int ret, year; + + year = dt->tm_year + 1900; + if (year >= 2100 || year < 2000) + return -EINVAL; + + ret = write_reg(dev, RHRCNT, BIN2BCD(dt->tm_hour)); + ret |= write_reg(dev, RMINCNT, BIN2BCD(dt->tm_min)); + ret |= write_reg(dev, RSECCNT, BIN2BCD(dt->tm_sec)); + ret |= write_reg(dev, RDAYCNT, BIN2BCD(dt->tm_mday)); + ret |= write_reg(dev, RMONCNT, BIN2BCD(dt->tm_mon + 1)); + ret |= write_reg(dev, RYRCNT, BIN2BCD(dt->tm_year - 100)); + ret |= write_reg(dev, RWKCNT, 1 << dt->tm_wday); + + return ret; +} + +static const struct rtc_class_ops r9701_rtc_ops = { + .read_time = r9701_get_datetime, + .set_time = r9701_set_datetime, +}; + +static int __devinit r9701_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + unsigned char tmp; + int res; + + rtc = rtc_device_register("r9701", + &spi->dev, &r9701_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + dev_set_drvdata(&spi->dev, rtc); + + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + spi_setup(spi); + + tmp = R100CNT; + res = read_regs(&spi->dev, &tmp, 1); + if (res || tmp != 0x20) { + rtc_device_unregister(rtc); + return res; + } + + return 0; +} + +static int __devexit r9701_remove(struct spi_device *spi) +{ + struct rtc_device *rtc = dev_get_drvdata(&spi->dev); + + rtc_device_unregister(rtc); + return 0; +} + +static struct spi_driver r9701_driver = { + .driver = { + .name = "rtc-r9701", + .bus = &spi_bus_type, + .owner = THIS_MODULE, + }, + .probe = r9701_probe, + .remove = __devexit_p(r9701_remove), +}; + +static __init int r9701_init(void) +{ + return spi_register_driver(&r9701_driver); +} +module_init(r9701_init); + +static __exit void r9701_exit(void) +{ + spi_unregister_driver(&r9701_driver); +} +module_exit(r9701_exit); + +MODULE_DESCRIPTION("r9701 spi RTC driver"); +MODULE_AUTHOR("Magnus Damm <damm@opensource.se>"); +MODULE_LICENSE("GPL"); |