Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 * An rtc/i2c driver for the Dallas DS1672
 * Copyright 2005-06 Tower Technologies
 *
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 */
 
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/module.h>
 
/* Registers */
 
#define DS1672_REG_CNT_BASE	0
#define DS1672_REG_CONTROL	4
#define DS1672_REG_TRICKLE	5
 
#define DS1672_REG_CONTROL_EOSC	0x80
 
/*
 * In the routines that deal directly with the ds1672 hardware, we use
 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
 * Time is set to UTC.
 */
static int ds1672_read_time(struct device *dev, struct rtc_time *tm)
{
<------>struct i2c_client *client = to_i2c_client(dev);
<------>unsigned long time;
<------>unsigned char addr = DS1672_REG_CONTROL;
<------>unsigned char buf[4];
 
<------>struct i2c_msg msgs[] = {
<------><------>{/* setup read ptr */
<------><------><------>.addr = client->addr,
<------><------><------>.len = 1,
<------><------><------>.buf = &addr
<------><------>},
<------><------>{/* read date */
<------><------><------>.addr = client->addr,
<------><------><------>.flags = I2C_M_RD,
<------><------><------>.len = 1,
<------><------><------>.buf = buf
<------><------>},
<------>};
 
<------>/* read control register */
<------>if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
<------><------>dev_warn(&client->dev, "Unable to read the control register\n");
<------><------>return -EIO;
<------>}
 
<------>if (buf[0] & DS1672_REG_CONTROL_EOSC) {
<------><------>dev_warn(&client->dev, "Oscillator not enabled. Set time to enable.\n");
<------><------>return -EINVAL;
<------>}
 
<------>addr = DS1672_REG_CNT_BASE;
<------>msgs[1].len = 4;
 
<------>/* read date registers */
<------>if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
<------><------>dev_err(&client->dev, "%s: read error\n", __func__);
<------><------>return -EIO;
<------>}
 
<------>dev_dbg(&client->dev,
<------><------>"%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
<------><------>__func__, buf[0], buf[1], buf[2], buf[3]);
 
<------>time = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
<------>       (buf[1] << 8) | buf[0];
 
<------>rtc_time64_to_tm(time, tm);
 
<------>dev_dbg(&client->dev, "%s: tm is %ptR\n", __func__, tm);
 
<------>return 0;
}
 
static int ds1672_set_time(struct device *dev, struct rtc_time *tm)
{
<------>struct i2c_client *client = to_i2c_client(dev);
<------>int xfer;
<------>unsigned char buf[6];
<------>unsigned long secs = rtc_tm_to_time64(tm);
 
<------>buf[0] = DS1672_REG_CNT_BASE;
<------>buf[1] = secs & 0x000000FF;
<------>buf[2] = (secs & 0x0000FF00) >> 8;
<------>buf[3] = (secs & 0x00FF0000) >> 16;
<------>buf[4] = (secs & 0xFF000000) >> 24;
<------>buf[5] = 0;		/* set control reg to enable counting */
 
<------>xfer = i2c_master_send(client, buf, 6);
<------>if (xfer != 6) {
<------><------>dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
<------><------>return -EIO;
<------>}
 
<------>return 0;
}
 
static const struct rtc_class_ops ds1672_rtc_ops = {
<------>.read_time = ds1672_read_time,
<------>.set_time = ds1672_set_time,
};
 
static int ds1672_probe(struct i2c_client *client,
<------><------><------>const struct i2c_device_id *id)
{
<------>int err = 0;
<------>struct rtc_device *rtc;
 
<------>dev_dbg(&client->dev, "%s\n", __func__);
 
<------>if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
<------><------>return -ENODEV;
 
<------>rtc = devm_rtc_allocate_device(&client->dev);
<------>if (IS_ERR(rtc))
<------><------>return PTR_ERR(rtc);
 
<------>rtc->ops = &ds1672_rtc_ops;
<------>rtc->range_max = U32_MAX;
 
<------>err = rtc_register_device(rtc);
<------>if (err)
<------><------>return err;
 
<------>i2c_set_clientdata(client, rtc);
 
<------>return 0;
}
 
static const struct i2c_device_id ds1672_id[] = {
<------>{ "ds1672", 0 },
<------>{ }
};
MODULE_DEVICE_TABLE(i2c, ds1672_id);
 
static const struct of_device_id ds1672_of_match[] = {
<------>{ .compatible = "dallas,ds1672" },
<------>{ }
};
MODULE_DEVICE_TABLE(of, ds1672_of_match);
 
static struct i2c_driver ds1672_driver = {
<------>.driver = {
<------><------>   .name = "rtc-ds1672",
<------><------>   .of_match_table = of_match_ptr(ds1672_of_match),
<------>},
<------>.probe = &ds1672_probe,
<------>.id_table = ds1672_id,
};
 
module_i2c_driver(ds1672_driver);
 
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
MODULE_LICENSE("GPL");