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Date: Thu, 20 Mar 2014 21:55:33 +0530 From: RAGHAVENDRA GANIGA <ravi23ganiga@...il.com> To: a.zummo@...ertech.it, linux-kernel@...r.kernel.org, rtc-linux@...glegroups.com Subject: [PATCH] rtc: add support for maxim dallas rtc ds1347 >From 64f99d0497c6de5157bc4931b47aadc266f5961e Mon Sep 17 00:00:00 2001 From: Raghavendra Ganiga <ravi23ganiga@...il.com> Date: Thu, 20 Mar 2014 00:53:30 +0530 Subject: [PATCH] rtc: add support for maxim dallas rtc ds1347 This is a patch to add support for maxim dallas rtc ds1347 Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@...il.com> --- drivers/rtc/Kconfig | 12 ++++ drivers/rtc/Makefile | 1 + drivers/rtc/rtc-ds1347.c | 175 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 188 insertions(+) create mode 100644 drivers/rtc/rtc-ds1347.c diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index db933de..2e565f8 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -573,6 +573,18 @@ config RTC_DRV_DS1305 This driver can also be built as a module. If so, the module will be called rtc-ds1305. +config RTC_DRV_DS1347 + tristate "Dallas/Maxim DS1347" + help + If you say yes here you get support for the + Dallas/Maxim DS1347 chips. + + This driver only supports the RTC feature, and not other chip + features such as alarms. + + This driver can also be built as a module. If so, the module + will be called rtc-ds1347. + config RTC_DRV_DS1390 tristate "Dallas/Maxim DS1390/93/94" help diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index b427bf7..40a0991 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -40,6 +40,7 @@ obj-$(CONFIG_RTC_DRV_DS1286) += rtc-ds1286.o obj-$(CONFIG_RTC_DRV_DS1302) += rtc-ds1302.o obj-$(CONFIG_RTC_DRV_DS1305) += rtc-ds1305.o obj-$(CONFIG_RTC_DRV_DS1307) += rtc-ds1307.o +obj-$(CONFIG_RTC_DRV_DS1347) += rtc-ds1347.o obj-$(CONFIG_RTC_DRV_DS1374) += rtc-ds1374.o obj-$(CONFIG_RTC_DRV_DS1390) += rtc-ds1390.o obj-$(CONFIG_RTC_DRV_DS1511) += rtc-ds1511.o diff --git a/drivers/rtc/rtc-ds1347.c b/drivers/rtc/rtc-ds1347.c new file mode 100644 index 0000000..3c9a934 --- /dev/null +++ b/drivers/rtc/rtc-ds1347.c @@ -0,0 +1,175 @@ +/* rtc-ds1347.c + * + * Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible + * Real Time Clock + * + * Author : Raghavendra Chandra Ganiga <ravi23ganiga@...il.com> + * + * 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/init.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/spi/spi.h> +#include <linux/bcd.h> + +/*Registers in ds1347 rtc*/ + +#define DS1347_SECONDS_REG 0x01 +#define DS1347_MINUTES_REG 0x03 +#define DS1347_HOURS_REG 0x05 +#define DS1347_DATE_REG 0x07 +#define DS1347_MONTH_REG 0x09 +#define DS1347_DAY_REG 0x0B +#define DS1347_YEAR_REG 0x0D +#define DS1347_CONTROL_REG 0x0F +#define DS1347_STATUS_REG 0x17 +#define DS1347_CLOCK_BURST 0x3F + + + +static int ds1347_read_reg(struct device *dev, unsigned char address, + unsigned char *data) +{ + struct spi_device *spi = to_spi_device(dev); + + *data = address | 0x80; + + return spi_write_then_read(spi, data, 1, data, 1); +} + +static int ds1347_write_reg(struct device *dev, unsigned char 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_then_read(spi, buf, 2, NULL, 0); +} + +static int ds1347_read_time(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + int err; + unsigned char buf[8]; + + buf[0] = DS1347_CLOCK_BURST | 0x80; + + err = spi_write_then_read(spi, buf, 1, buf, 8); + if (err) + return err; + + dt->tm_sec = bcd2bin(buf[0]); + dt->tm_min = bcd2bin(buf[1]); + dt->tm_hour = bcd2bin(buf[2] & 0x3F); + dt->tm_mday = bcd2bin(buf[3]); + dt->tm_mon = bcd2bin(buf[4]) - 1; + dt->tm_wday = bcd2bin(buf[5]) - 1; + dt->tm_year = bcd2bin(buf[6]) + 100; + + return rtc_valid_tm(dt); +} + +static int ds1347_set_time(struct device *dev, struct rtc_time *dt) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[9]; + + buf[0] = DS1347_CLOCK_BURST & 0x7F; + buf[1] = bin2bcd(dt->tm_sec); + buf[2] = bin2bcd(dt->tm_min); + buf[3] = (bin2bcd(dt->tm_hour) & 0x3F); + buf[4] = bin2bcd(dt->tm_mday); + buf[5] = bin2bcd(dt->tm_mon + 1); + buf[6] = bin2bcd(dt->tm_wday + 1); + + /*year in linux is from 1900 i.e in range of 100 + in rtc it is from 00 to 99 so subtract + the linux year by 100*/ + if (dt->tm_year >= 100) + dt->tm_year -= 100; + + buf[7] = bin2bcd(dt->tm_year); + buf[8] = bin2bcd(0x00); + + /*write the rtc settings*/ + return spi_write_then_read(spi, buf, 9, NULL, 0); +} + + + +static const struct rtc_class_ops ds1347_rtc_ops = { + .read_time = ds1347_read_time, + .set_time = ds1347_set_time, +}; + +static int ds1347_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + unsigned char data; + int res; + + /*spi setup with ds1347 in mode 3 and bits per word as 8*/ + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + spi_setup(spi); + + /*RTC Settings*/ + + /*check if spi read is successfull*/ + res = ds1347_read_reg(&spi->dev, DS1347_SECONDS_REG, &data); + if (res) + return res; + + /*Disable the write protect of rtc*/ + ds1347_read_reg(&spi->dev, DS1347_CONTROL_REG, &data); + data = data & ~(1<<7); + ds1347_write_reg(&spi->dev, DS1347_CONTROL_REG, data); + + /*Enable the oscillator , disable the oscillator stop flag, + and glitch filter to reduce current consumption*/ + ds1347_read_reg(&spi->dev, DS1347_STATUS_REG, &data); + data = data & 0x1B; + ds1347_write_reg(&spi->dev, DS1347_STATUS_REG, data); + + /*display the settings*/ + ds1347_read_reg(&spi->dev, DS1347_CONTROL_REG, &data); + dev_info(&spi->dev, "DS1347 RTC CTRL Reg = 0x%02x\n", data); + + ds1347_read_reg(&spi->dev, DS1347_STATUS_REG, &data); + dev_info(&spi->dev, "DS1347 RTC Status Reg = 0x%02x\n", data); + + rtc = devm_rtc_device_register(&spi->dev, "ds1347", + &ds1347_rtc_ops, THIS_MODULE); + + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + spi_set_drvdata(spi, rtc); + + return 0; +} + +static struct spi_driver ds1347_driver = { + .driver = { + .name = "ds1347", + .owner = THIS_MODULE, + }, + .probe = ds1347_probe, +}; + +module_spi_driver(ds1347_driver); + +MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER"); +MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@...il.com>"); +MODULE_LICENSE("GPL"); + -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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