cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

rtc-ds1672.c (3664B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * An rtc/i2c driver for the Dallas DS1672
      4 * Copyright 2005-06 Tower Technologies
      5 *
      6 * Author: Alessandro Zummo <a.zummo@towertech.it>
      7 */
      8
      9#include <linux/i2c.h>
     10#include <linux/rtc.h>
     11#include <linux/module.h>
     12
     13/* Registers */
     14
     15#define DS1672_REG_CNT_BASE	0
     16#define DS1672_REG_CONTROL	4
     17#define DS1672_REG_TRICKLE	5
     18
     19#define DS1672_REG_CONTROL_EOSC	0x80
     20
     21/*
     22 * In the routines that deal directly with the ds1672 hardware, we use
     23 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
     24 * Time is set to UTC.
     25 */
     26static int ds1672_read_time(struct device *dev, struct rtc_time *tm)
     27{
     28	struct i2c_client *client = to_i2c_client(dev);
     29	unsigned long time;
     30	unsigned char addr = DS1672_REG_CONTROL;
     31	unsigned char buf[4];
     32
     33	struct i2c_msg msgs[] = {
     34		{/* setup read ptr */
     35			.addr = client->addr,
     36			.len = 1,
     37			.buf = &addr
     38		},
     39		{/* read date */
     40			.addr = client->addr,
     41			.flags = I2C_M_RD,
     42			.len = 1,
     43			.buf = buf
     44		},
     45	};
     46
     47	/* read control register */
     48	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
     49		dev_warn(&client->dev, "Unable to read the control register\n");
     50		return -EIO;
     51	}
     52
     53	if (buf[0] & DS1672_REG_CONTROL_EOSC) {
     54		dev_warn(&client->dev, "Oscillator not enabled. Set time to enable.\n");
     55		return -EINVAL;
     56	}
     57
     58	addr = DS1672_REG_CNT_BASE;
     59	msgs[1].len = 4;
     60
     61	/* read date registers */
     62	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
     63		dev_err(&client->dev, "%s: read error\n", __func__);
     64		return -EIO;
     65	}
     66
     67	dev_dbg(&client->dev,
     68		"%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
     69		__func__, buf[0], buf[1], buf[2], buf[3]);
     70
     71	time = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
     72	       (buf[1] << 8) | buf[0];
     73
     74	rtc_time64_to_tm(time, tm);
     75
     76	dev_dbg(&client->dev, "%s: tm is %ptR\n", __func__, tm);
     77
     78	return 0;
     79}
     80
     81static int ds1672_set_time(struct device *dev, struct rtc_time *tm)
     82{
     83	struct i2c_client *client = to_i2c_client(dev);
     84	int xfer;
     85	unsigned char buf[6];
     86	unsigned long secs = rtc_tm_to_time64(tm);
     87
     88	buf[0] = DS1672_REG_CNT_BASE;
     89	buf[1] = secs & 0x000000FF;
     90	buf[2] = (secs & 0x0000FF00) >> 8;
     91	buf[3] = (secs & 0x00FF0000) >> 16;
     92	buf[4] = (secs & 0xFF000000) >> 24;
     93	buf[5] = 0;		/* set control reg to enable counting */
     94
     95	xfer = i2c_master_send(client, buf, 6);
     96	if (xfer != 6) {
     97		dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
     98		return -EIO;
     99	}
    100
    101	return 0;
    102}
    103
    104static const struct rtc_class_ops ds1672_rtc_ops = {
    105	.read_time = ds1672_read_time,
    106	.set_time = ds1672_set_time,
    107};
    108
    109static int ds1672_probe(struct i2c_client *client,
    110			const struct i2c_device_id *id)
    111{
    112	int err = 0;
    113	struct rtc_device *rtc;
    114
    115	dev_dbg(&client->dev, "%s\n", __func__);
    116
    117	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
    118		return -ENODEV;
    119
    120	rtc = devm_rtc_allocate_device(&client->dev);
    121	if (IS_ERR(rtc))
    122		return PTR_ERR(rtc);
    123
    124	rtc->ops = &ds1672_rtc_ops;
    125	rtc->range_max = U32_MAX;
    126
    127	err = devm_rtc_register_device(rtc);
    128	if (err)
    129		return err;
    130
    131	i2c_set_clientdata(client, rtc);
    132
    133	return 0;
    134}
    135
    136static const struct i2c_device_id ds1672_id[] = {
    137	{ "ds1672", 0 },
    138	{ }
    139};
    140MODULE_DEVICE_TABLE(i2c, ds1672_id);
    141
    142static const __maybe_unused struct of_device_id ds1672_of_match[] = {
    143	{ .compatible = "dallas,ds1672" },
    144	{ }
    145};
    146MODULE_DEVICE_TABLE(of, ds1672_of_match);
    147
    148static struct i2c_driver ds1672_driver = {
    149	.driver = {
    150		   .name = "rtc-ds1672",
    151		   .of_match_table = of_match_ptr(ds1672_of_match),
    152	},
    153	.probe = &ds1672_probe,
    154	.id_table = ds1672_id,
    155};
    156
    157module_i2c_driver(ds1672_driver);
    158
    159MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
    160MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
    161MODULE_LICENSE("GPL");