cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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rtc-em3027.c (3747B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * An rtc/i2c driver for the EM Microelectronic EM3027
      4 * Copyright 2011 CompuLab, Ltd.
      5 *
      6 * Author: Mike Rapoport <mike@compulab.co.il>
      7 *
      8 * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
      9 */
     10
     11#include <linux/i2c.h>
     12#include <linux/rtc.h>
     13#include <linux/bcd.h>
     14#include <linux/module.h>
     15#include <linux/of.h>
     16
     17/* Registers */
     18#define EM3027_REG_ON_OFF_CTRL	0x00
     19#define EM3027_REG_IRQ_CTRL	0x01
     20#define EM3027_REG_IRQ_FLAGS	0x02
     21#define EM3027_REG_STATUS	0x03
     22#define EM3027_REG_RST_CTRL	0x04
     23
     24#define EM3027_REG_WATCH_SEC	0x08
     25#define EM3027_REG_WATCH_MIN	0x09
     26#define EM3027_REG_WATCH_HOUR	0x0a
     27#define EM3027_REG_WATCH_DATE	0x0b
     28#define EM3027_REG_WATCH_DAY	0x0c
     29#define EM3027_REG_WATCH_MON	0x0d
     30#define EM3027_REG_WATCH_YEAR	0x0e
     31
     32#define EM3027_REG_ALARM_SEC	0x10
     33#define EM3027_REG_ALARM_MIN	0x11
     34#define EM3027_REG_ALARM_HOUR	0x12
     35#define EM3027_REG_ALARM_DATE	0x13
     36#define EM3027_REG_ALARM_DAY	0x14
     37#define EM3027_REG_ALARM_MON	0x15
     38#define EM3027_REG_ALARM_YEAR	0x16
     39
     40static struct i2c_driver em3027_driver;
     41
     42static int em3027_get_time(struct device *dev, struct rtc_time *tm)
     43{
     44	struct i2c_client *client = to_i2c_client(dev);
     45
     46	unsigned char addr = EM3027_REG_WATCH_SEC;
     47	unsigned char buf[7];
     48
     49	struct i2c_msg msgs[] = {
     50		{/* setup read addr */
     51			.addr = client->addr,
     52			.len = 1,
     53			.buf = &addr
     54		},
     55		{/* read time/date */
     56			.addr = client->addr,
     57			.flags = I2C_M_RD,
     58			.len = 7,
     59			.buf = buf
     60		},
     61	};
     62
     63	/* read time/date registers */
     64	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
     65		dev_err(&client->dev, "%s: read error\n", __func__);
     66		return -EIO;
     67	}
     68
     69	tm->tm_sec	= bcd2bin(buf[0]);
     70	tm->tm_min	= bcd2bin(buf[1]);
     71	tm->tm_hour	= bcd2bin(buf[2]);
     72	tm->tm_mday	= bcd2bin(buf[3]);
     73	tm->tm_wday	= bcd2bin(buf[4]);
     74	tm->tm_mon	= bcd2bin(buf[5]) - 1;
     75	tm->tm_year	= bcd2bin(buf[6]) + 100;
     76
     77	return 0;
     78}
     79
     80static int em3027_set_time(struct device *dev, struct rtc_time *tm)
     81{
     82	struct i2c_client *client = to_i2c_client(dev);
     83	unsigned char buf[8];
     84
     85	struct i2c_msg msg = {
     86		.addr = client->addr,
     87		.len = 8,
     88		.buf = buf,	/* write time/date */
     89	};
     90
     91	buf[0] = EM3027_REG_WATCH_SEC;
     92	buf[1] = bin2bcd(tm->tm_sec);
     93	buf[2] = bin2bcd(tm->tm_min);
     94	buf[3] = bin2bcd(tm->tm_hour);
     95	buf[4] = bin2bcd(tm->tm_mday);
     96	buf[5] = bin2bcd(tm->tm_wday);
     97	buf[6] = bin2bcd(tm->tm_mon + 1);
     98	buf[7] = bin2bcd(tm->tm_year % 100);
     99
    100	/* write time/date registers */
    101	if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
    102		dev_err(&client->dev, "%s: write error\n", __func__);
    103		return -EIO;
    104	}
    105
    106	return 0;
    107}
    108
    109static const struct rtc_class_ops em3027_rtc_ops = {
    110	.read_time = em3027_get_time,
    111	.set_time = em3027_set_time,
    112};
    113
    114static int em3027_probe(struct i2c_client *client,
    115			const struct i2c_device_id *id)
    116{
    117	struct rtc_device *rtc;
    118
    119	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
    120		return -ENODEV;
    121
    122	rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,
    123				  &em3027_rtc_ops, THIS_MODULE);
    124	if (IS_ERR(rtc))
    125		return PTR_ERR(rtc);
    126
    127	i2c_set_clientdata(client, rtc);
    128
    129	return 0;
    130}
    131
    132static const struct i2c_device_id em3027_id[] = {
    133	{ "em3027", 0 },
    134	{ }
    135};
    136MODULE_DEVICE_TABLE(i2c, em3027_id);
    137
    138#ifdef CONFIG_OF
    139static const struct of_device_id em3027_of_match[] = {
    140	{ .compatible = "emmicro,em3027", },
    141	{}
    142};
    143MODULE_DEVICE_TABLE(of, em3027_of_match);
    144#endif
    145
    146static struct i2c_driver em3027_driver = {
    147	.driver = {
    148		   .name = "rtc-em3027",
    149		   .of_match_table = of_match_ptr(em3027_of_match),
    150	},
    151	.probe = &em3027_probe,
    152	.id_table = em3027_id,
    153};
    154
    155module_i2c_driver(em3027_driver);
    156
    157MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
    158MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
    159MODULE_LICENSE("GPL");