u-boot/drivers/rtc/isl1208.c
Trent Piepho 4a094725b4 rtc: Add read8 and write8 support to isl1208 driver
This can be used for device register access from board code.

This allows access to capabilities in the RTC chip not abstracted in
U-Boot's RTC class.  E.g., device NVRAM or a tamper detection circuit.

Cc: Klaus Goger <klaus.goger@theobroma-systems.com>
Cc: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Trent Piepho <tpiepho@impinj.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
2018-10-08 14:45:02 -04:00

197 lines
4.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2008
* Tor Krill, Excito Elektronik i Skåne , tor@excito.com
*
* Modelled after the ds1337 driver
*/
/*
* Date & Time support (no alarms) for Intersil
* ISL1208 Real Time Clock (RTC).
*/
#include <common.h>
#include <command.h>
#include <dm.h>
#include <rtc.h>
#include <i2c.h>
/*---------------------------------------------------------------------*/
#ifdef DEBUG_RTC
#define DEBUGR(fmt,args...) printf(fmt ,##args)
#else
#define DEBUGR(fmt,args...)
#endif
/*---------------------------------------------------------------------*/
/*
* RTC register addresses
*/
#define RTC_SEC_REG_ADDR 0x0
#define RTC_MIN_REG_ADDR 0x1
#define RTC_HR_REG_ADDR 0x2
#define RTC_DATE_REG_ADDR 0x3
#define RTC_MON_REG_ADDR 0x4
#define RTC_YR_REG_ADDR 0x5
#define RTC_DAY_REG_ADDR 0x6
#define RTC_STAT_REG_ADDR 0x7
/*
* RTC control register bits
*/
/*
* RTC status register bits
*/
#define RTC_STAT_BIT_ARST 0x80 /* AUTO RESET ENABLE BIT */
#define RTC_STAT_BIT_XTOSCB 0x40 /* CRYSTAL OSCILLATOR ENABLE BIT */
#define RTC_STAT_BIT_WRTC 0x10 /* WRITE RTC ENABLE BIT */
#define RTC_STAT_BIT_ALM 0x04 /* ALARM BIT */
#define RTC_STAT_BIT_BAT 0x02 /* BATTERY BIT */
#define RTC_STAT_BIT_RTCF 0x01 /* REAL TIME CLOCK FAIL BIT */
/*
* Read an RTC register
*/
static int isl1208_rtc_read8(struct udevice *dev, unsigned int reg)
{
return dm_i2c_reg_read(dev, reg);
}
/*
* Write an RTC register
*/
static int isl1208_rtc_write8(struct udevice *dev, unsigned int reg, int val)
{
return dm_i2c_reg_write(dev, reg, val);
}
/*
* Get the current time from the RTC
*/
static int isl1208_rtc_get(struct udevice *dev, struct rtc_time *tmp)
{
int ret;
uchar buf[8], val;
ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
if (ret < 0)
return ret;
if (buf[RTC_STAT_REG_ADDR] & RTC_STAT_BIT_RTCF) {
printf ("### Warning: RTC oscillator has stopped\n");
ret = dm_i2c_read(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
if (ret < 0)
return ret;
val = val & ~(RTC_STAT_BIT_BAT | RTC_STAT_BIT_RTCF);
ret = dm_i2c_write(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
if (ret < 0)
return ret;
}
tmp->tm_sec = bcd2bin(buf[RTC_SEC_REG_ADDR] & 0x7F);
tmp->tm_min = bcd2bin(buf[RTC_MIN_REG_ADDR] & 0x7F);
tmp->tm_hour = bcd2bin(buf[RTC_HR_REG_ADDR] & 0x3F);
tmp->tm_mday = bcd2bin(buf[RTC_DATE_REG_ADDR] & 0x3F);
tmp->tm_mon = bcd2bin(buf[RTC_MON_REG_ADDR] & 0x1F);
tmp->tm_year = bcd2bin(buf[RTC_YR_REG_ADDR]) + 2000;
tmp->tm_wday = bcd2bin(buf[RTC_DAY_REG_ADDR] & 0x07);
tmp->tm_yday = 0;
tmp->tm_isdst= 0;
DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
return 0;
}
/*
* Set the RTC
*/
static int isl1208_rtc_set(struct udevice *dev, const struct rtc_time *tmp)
{
int ret;
uchar val, buf[7];
DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
if (tmp->tm_year < 2000 || tmp->tm_year > 2099)
printf("WARNING: year should be between 2000 and 2099!\n");
/* enable write */
ret = dm_i2c_read(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
if (ret < 0)
return ret;
val = val | RTC_STAT_BIT_WRTC;
ret = dm_i2c_write(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
if (ret < 0)
return ret;
buf[RTC_YR_REG_ADDR] = bin2bcd(tmp->tm_year % 100);
buf[RTC_MON_REG_ADDR] = bin2bcd(tmp->tm_mon);
buf[RTC_DAY_REG_ADDR] = bin2bcd(tmp->tm_wday);
buf[RTC_DATE_REG_ADDR] = bin2bcd(tmp->tm_mday);
buf[RTC_HR_REG_ADDR] = bin2bcd(tmp->tm_hour) | 0x80; /* 24h clock */
buf[RTC_MIN_REG_ADDR] = bin2bcd(tmp->tm_min);
buf[RTC_SEC_REG_ADDR] = bin2bcd(tmp->tm_sec);
ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
if (ret < 0)
return ret;
/* disable write */
ret = dm_i2c_read(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
if (ret < 0)
return ret;
val = val & ~RTC_STAT_BIT_WRTC;
ret = dm_i2c_write(dev, RTC_STAT_REG_ADDR, &val, sizeof(val));
if (ret < 0)
return ret;
return 0;
}
static int isl1208_rtc_reset(struct udevice *dev)
{
return 0;
}
static int isl1208_probe(struct udevice *dev)
{
i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
DM_I2C_CHIP_WR_ADDRESS);
return 0;
}
static const struct rtc_ops isl1208_rtc_ops = {
.get = isl1208_rtc_get,
.set = isl1208_rtc_set,
.reset = isl1208_rtc_reset,
.read8 = isl1208_rtc_read8,
.write8 = isl1208_rtc_write8,
};
static const struct udevice_id isl1208_rtc_ids[] = {
{ .compatible = "isil,isl1208" },
{ }
};
U_BOOT_DRIVER(rtc_isl1208) = {
.name = "rtc-isl1208",
.id = UCLASS_RTC,
.probe = isl1208_probe,
.of_match = isl1208_rtc_ids,
.ops = &isl1208_rtc_ops,
};