forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
318 lines
6.5 KiB
318 lines
6.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* drivers/rtc/rtc-pcf8583.c |
|
* |
|
* Copyright (C) 2000 Russell King |
|
* Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix |
|
* |
|
* Driver for PCF8583 RTC & RAM chip |
|
* |
|
* Converted to the generic RTC susbsystem by G. Liakhovetski (2006) |
|
*/ |
|
#include <linux/module.h> |
|
#include <linux/i2c.h> |
|
#include <linux/slab.h> |
|
#include <linux/rtc.h> |
|
#include <linux/init.h> |
|
#include <linux/err.h> |
|
#include <linux/errno.h> |
|
#include <linux/bcd.h> |
|
|
|
struct rtc_mem { |
|
unsigned int loc; |
|
unsigned int nr; |
|
unsigned char *data; |
|
}; |
|
|
|
struct pcf8583 { |
|
struct rtc_device *rtc; |
|
unsigned char ctrl; |
|
}; |
|
|
|
#define CTRL_STOP 0x80 |
|
#define CTRL_HOLD 0x40 |
|
#define CTRL_32KHZ 0x00 |
|
#define CTRL_MASK 0x08 |
|
#define CTRL_ALARMEN 0x04 |
|
#define CTRL_ALARM 0x02 |
|
#define CTRL_TIMER 0x01 |
|
|
|
|
|
static struct i2c_driver pcf8583_driver; |
|
|
|
#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl |
|
#define set_ctrl(x, v) get_ctrl(x) = v |
|
|
|
#define CMOS_YEAR (64 + 128) |
|
#define CMOS_CHECKSUM (63) |
|
|
|
static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt) |
|
{ |
|
unsigned char buf[8], addr[1] = { 1 }; |
|
struct i2c_msg msgs[2] = { |
|
{ |
|
.addr = client->addr, |
|
.flags = 0, |
|
.len = 1, |
|
.buf = addr, |
|
}, { |
|
.addr = client->addr, |
|
.flags = I2C_M_RD, |
|
.len = 6, |
|
.buf = buf, |
|
} |
|
}; |
|
int ret; |
|
|
|
memset(buf, 0, sizeof(buf)); |
|
|
|
ret = i2c_transfer(client->adapter, msgs, 2); |
|
if (ret == 2) { |
|
dt->tm_year = buf[4] >> 6; |
|
dt->tm_wday = buf[5] >> 5; |
|
|
|
buf[4] &= 0x3f; |
|
buf[5] &= 0x1f; |
|
|
|
dt->tm_sec = bcd2bin(buf[1]); |
|
dt->tm_min = bcd2bin(buf[2]); |
|
dt->tm_hour = bcd2bin(buf[3]); |
|
dt->tm_mday = bcd2bin(buf[4]); |
|
dt->tm_mon = bcd2bin(buf[5]) - 1; |
|
} |
|
|
|
return ret == 2 ? 0 : -EIO; |
|
} |
|
|
|
static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo) |
|
{ |
|
unsigned char buf[8]; |
|
int ret, len = 6; |
|
|
|
buf[0] = 0; |
|
buf[1] = get_ctrl(client) | 0x80; |
|
buf[2] = 0; |
|
buf[3] = bin2bcd(dt->tm_sec); |
|
buf[4] = bin2bcd(dt->tm_min); |
|
buf[5] = bin2bcd(dt->tm_hour); |
|
|
|
if (datetoo) { |
|
len = 8; |
|
buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6); |
|
buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5); |
|
} |
|
|
|
ret = i2c_master_send(client, (char *)buf, len); |
|
if (ret != len) |
|
return -EIO; |
|
|
|
buf[1] = get_ctrl(client); |
|
ret = i2c_master_send(client, (char *)buf, 2); |
|
|
|
return ret == 2 ? 0 : -EIO; |
|
} |
|
|
|
static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl) |
|
{ |
|
*ctrl = get_ctrl(client); |
|
return 0; |
|
} |
|
|
|
static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl) |
|
{ |
|
unsigned char buf[2]; |
|
|
|
buf[0] = 0; |
|
buf[1] = *ctrl; |
|
set_ctrl(client, *ctrl); |
|
|
|
return i2c_master_send(client, (char *)buf, 2); |
|
} |
|
|
|
static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem) |
|
{ |
|
unsigned char addr[1]; |
|
struct i2c_msg msgs[2] = { |
|
{ |
|
.addr = client->addr, |
|
.flags = 0, |
|
.len = 1, |
|
.buf = addr, |
|
}, { |
|
.addr = client->addr, |
|
.flags = I2C_M_RD, |
|
.len = mem->nr, |
|
.buf = mem->data, |
|
} |
|
}; |
|
|
|
if (mem->loc < 8) |
|
return -EINVAL; |
|
|
|
addr[0] = mem->loc; |
|
|
|
return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; |
|
} |
|
|
|
static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem) |
|
{ |
|
unsigned char buf[9]; |
|
int ret; |
|
|
|
if (mem->loc < 8 || mem->nr > 8) |
|
return -EINVAL; |
|
|
|
buf[0] = mem->loc; |
|
memcpy(buf + 1, mem->data, mem->nr); |
|
|
|
ret = i2c_master_send(client, buf, mem->nr + 1); |
|
return ret == mem->nr + 1 ? 0 : -EIO; |
|
} |
|
|
|
static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm) |
|
{ |
|
struct i2c_client *client = to_i2c_client(dev); |
|
unsigned char ctrl, year[2]; |
|
struct rtc_mem mem = { |
|
.loc = CMOS_YEAR, |
|
.nr = sizeof(year), |
|
.data = year |
|
}; |
|
int real_year, year_offset, err; |
|
|
|
/* |
|
* Ensure that the RTC is running. |
|
*/ |
|
pcf8583_get_ctrl(client, &ctrl); |
|
if (ctrl & (CTRL_STOP | CTRL_HOLD)) { |
|
unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD); |
|
|
|
dev_warn(dev, "resetting control %02x -> %02x\n", |
|
ctrl, new_ctrl); |
|
|
|
err = pcf8583_set_ctrl(client, &new_ctrl); |
|
if (err < 0) |
|
return err; |
|
} |
|
|
|
if (pcf8583_get_datetime(client, tm) || |
|
pcf8583_read_mem(client, &mem)) |
|
return -EIO; |
|
|
|
real_year = year[0]; |
|
|
|
/* |
|
* The RTC year holds the LSB two bits of the current |
|
* year, which should reflect the LSB two bits of the |
|
* CMOS copy of the year. Any difference indicates |
|
* that we have to correct the CMOS version. |
|
*/ |
|
year_offset = tm->tm_year - (real_year & 3); |
|
if (year_offset < 0) |
|
/* |
|
* RTC year wrapped. Adjust it appropriately. |
|
*/ |
|
year_offset += 4; |
|
|
|
tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900; |
|
|
|
return 0; |
|
} |
|
|
|
static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm) |
|
{ |
|
struct i2c_client *client = to_i2c_client(dev); |
|
unsigned char year[2], chk; |
|
struct rtc_mem cmos_year = { |
|
.loc = CMOS_YEAR, |
|
.nr = sizeof(year), |
|
.data = year |
|
}; |
|
struct rtc_mem cmos_check = { |
|
.loc = CMOS_CHECKSUM, |
|
.nr = 1, |
|
.data = &chk |
|
}; |
|
unsigned int proper_year = tm->tm_year + 1900; |
|
int ret; |
|
|
|
/* |
|
* The RTC's own 2-bit year must reflect the least |
|
* significant two bits of the CMOS year. |
|
*/ |
|
|
|
ret = pcf8583_set_datetime(client, tm, 1); |
|
if (ret) |
|
return ret; |
|
|
|
ret = pcf8583_read_mem(client, &cmos_check); |
|
if (ret) |
|
return ret; |
|
|
|
ret = pcf8583_read_mem(client, &cmos_year); |
|
if (ret) |
|
return ret; |
|
|
|
chk -= year[1] + year[0]; |
|
|
|
year[1] = proper_year / 100; |
|
year[0] = proper_year % 100; |
|
|
|
chk += year[1] + year[0]; |
|
|
|
ret = pcf8583_write_mem(client, &cmos_year); |
|
|
|
if (ret) |
|
return ret; |
|
|
|
ret = pcf8583_write_mem(client, &cmos_check); |
|
|
|
return ret; |
|
} |
|
|
|
static const struct rtc_class_ops pcf8583_rtc_ops = { |
|
.read_time = pcf8583_rtc_read_time, |
|
.set_time = pcf8583_rtc_set_time, |
|
}; |
|
|
|
static int pcf8583_probe(struct i2c_client *client, |
|
const struct i2c_device_id *id) |
|
{ |
|
struct pcf8583 *pcf8583; |
|
|
|
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
|
return -ENODEV; |
|
|
|
pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583), |
|
GFP_KERNEL); |
|
if (!pcf8583) |
|
return -ENOMEM; |
|
|
|
i2c_set_clientdata(client, pcf8583); |
|
|
|
pcf8583->rtc = devm_rtc_device_register(&client->dev, |
|
pcf8583_driver.driver.name, |
|
&pcf8583_rtc_ops, THIS_MODULE); |
|
|
|
return PTR_ERR_OR_ZERO(pcf8583->rtc); |
|
} |
|
|
|
static const struct i2c_device_id pcf8583_id[] = { |
|
{ "pcf8583", 0 }, |
|
{ } |
|
}; |
|
MODULE_DEVICE_TABLE(i2c, pcf8583_id); |
|
|
|
static struct i2c_driver pcf8583_driver = { |
|
.driver = { |
|
.name = "pcf8583", |
|
}, |
|
.probe = pcf8583_probe, |
|
.id_table = pcf8583_id, |
|
}; |
|
|
|
module_i2c_driver(pcf8583_driver); |
|
|
|
MODULE_AUTHOR("Russell King"); |
|
MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); |
|
MODULE_LICENSE("GPL");
|
|
|