rtc: add EM3027 rtc driver (ae3551f9) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/rtc/Kconfig

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		@@ -361,6 +361,15 @@ config RTC_DRV_RX8025
		This driver can also be built as a module. If so, the module
		will be called rtc-rx8025.

		config RTC_DRV_EM3027
		tristate "EM Microelectronic EM3027"
		help
		If you say yes here you get support for the EM
		Microelectronic EM3027 RTC chips.

		This driver can also be built as a module. If so, the module
		will be called rtc-em3027.

		endif # I2C

		comment "SPI RTC drivers"

drivers/rtc/Makefile

+1 −0

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		@@ -44,6 +44,7 @@ obj-$(CONFIG_RTC_DRV_DS1742) += rtc-ds1742.o
		obj-$(CONFIG_RTC_DRV_DS3232) += rtc-ds3232.o
		obj-$(CONFIG_RTC_DRV_DS3234) += rtc-ds3234.o
		obj-$(CONFIG_RTC_DRV_EFI) += rtc-efi.o
		obj-$(CONFIG_RTC_DRV_EM3027) += rtc-em3027.o
		obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
		obj-$(CONFIG_RTC_DRV_FM3130) += rtc-fm3130.o
		obj-$(CONFIG_RTC_DRV_GENERIC) += rtc-generic.o

drivers/rtc/rtc-em3027.c

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+161 −0

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		/*
		* An rtc/i2c driver for the EM Microelectronic EM3027
		* Copyright 2011 CompuLab, Ltd.
		*
		* Author: Mike Rapoport <mike@compulab.co.il>
		*
		* Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
		*
		* 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/rtc.h>
		#include <linux/bcd.h>

		/* Registers */
		#define EM3027_REG_ON_OFF_CTRL 0x00
		#define EM3027_REG_IRQ_CTRL 0x01
		#define EM3027_REG_IRQ_FLAGS 0x02
		#define EM3027_REG_STATUS 0x03
		#define EM3027_REG_RST_CTRL 0x04

		#define EM3027_REG_WATCH_SEC 0x08
		#define EM3027_REG_WATCH_MIN 0x09
		#define EM3027_REG_WATCH_HOUR 0x0a
		#define EM3027_REG_WATCH_DATE 0x0b
		#define EM3027_REG_WATCH_DAY 0x0c
		#define EM3027_REG_WATCH_MON 0x0d
		#define EM3027_REG_WATCH_YEAR 0x0e

		#define EM3027_REG_ALARM_SEC 0x10
		#define EM3027_REG_ALARM_MIN 0x11
		#define EM3027_REG_ALARM_HOUR 0x12
		#define EM3027_REG_ALARM_DATE 0x13
		#define EM3027_REG_ALARM_DAY 0x14
		#define EM3027_REG_ALARM_MON 0x15
		#define EM3027_REG_ALARM_YEAR 0x16

		static struct i2c_driver em3027_driver;

		static int em3027_get_time(struct device dev, struct rtc_time tm)
		{
		struct i2c_client *client = to_i2c_client(dev);

		unsigned char addr = EM3027_REG_WATCH_SEC;
		unsigned char buf[7];

		struct i2c_msg msgs[] = {
		{client->addr, 0, 1, &addr}, /* setup read addr */
		{client->addr, I2C_M_RD, 7, buf}, /* read time/date */
		};

		/* read time/date registers */
		if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
		dev_err(&client->dev, "%s: read error\n", __func__);
		return -EIO;
		}

		tm->tm_sec = bcd2bin(buf[0]);
		tm->tm_min = bcd2bin(buf[1]);
		tm->tm_hour = bcd2bin(buf[2]);
		tm->tm_mday = bcd2bin(buf[3]);
		tm->tm_wday = bcd2bin(buf[4]);
		tm->tm_mon = bcd2bin(buf[5]);
		tm->tm_year = bcd2bin(buf[6]) + 100;

		return 0;
		}

		static int em3027_set_time(struct device dev, struct rtc_time tm)
		{
		struct i2c_client *client = to_i2c_client(dev);
		unsigned char buf[8];

		struct i2c_msg msg = {
		client->addr, 0, 8, buf, /* write time/date */
		};

		buf[0] = EM3027_REG_WATCH_SEC;
		buf[1] = bin2bcd(tm->tm_sec);
		buf[2] = bin2bcd(tm->tm_min);
		buf[3] = bin2bcd(tm->tm_hour);
		buf[4] = bin2bcd(tm->tm_mday);
		buf[5] = bin2bcd(tm->tm_wday);
		buf[6] = bin2bcd(tm->tm_mon);
		buf[7] = bin2bcd(tm->tm_year % 100);

		/* write time/date registers */
		if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
		dev_err(&client->dev, "%s: write error\n", __func__);
		return -EIO;
		}

		return 0;
		}

		static const struct rtc_class_ops em3027_rtc_ops = {
		.read_time = em3027_get_time,
		.set_time = em3027_set_time,
		};

		static int em3027_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
		{
		struct rtc_device *rtc;

		if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

		rtc = rtc_device_register(em3027_driver.driver.name, &client->dev,
		&em3027_rtc_ops, THIS_MODULE);
		if (IS_ERR(rtc))
		return PTR_ERR(rtc);

		i2c_set_clientdata(client, rtc);

		return 0;
		}

		static int em3027_remove(struct i2c_client *client)
		{
		struct rtc_device *rtc = i2c_get_clientdata(client);

		if (rtc)
		rtc_device_unregister(rtc);

		return 0;
		}

		static struct i2c_device_id em3027_id[] = {
		{ "em3027", 0 },
		{ }
		};

		static struct i2c_driver em3027_driver = {
		.driver = {
		.name = "rtc-em3027",
		},
		.probe = &em3027_probe,
		.remove = &em3027_remove,
		.id_table = em3027_id,
		};

		static int __init em3027_init(void)
		{
		return i2c_add_driver(&em3027_driver);
		}

		static void __exit em3027_exit(void)
		{
		i2c_del_driver(&em3027_driver);
		}

		MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
		MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
		MODULE_LICENSE("GPL");

		module_init(em3027_init);
		module_exit(em3027_exit);