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u-boot/drivers/rtc/s35392a.c
Nandor Han da5337a61c rtc: add support for s35392a 
Add support for S35392A RTC. The driver supports both U-Boot driver
models.

Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Cc: Heiko Schocher <hs@denx.de>
2017-11-20 09:58:31 +01:00

366 lines
7.8 KiB
C
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/*
* SII Semiconductor Corporation S35392A RTC driver.
*
* Copyright (c) 2017, General Electric Company
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* SPDX-License-Identifier: GPL-2.0
*/
#include <command.h>
#include <common.h>
#include <dm.h>
#include <i2c.h>
#include <linux/bitrev.h>
#include <rtc.h>
#define S35390A_CMD_STATUS1 0x30
#define S35390A_CMD_STATUS2 0x31
#define S35390A_CMD_TIME1 0x32
#define S35390A_CMD_TIME2 0x33
#define S35390A_CMD_INT2_REG1 0x35
#define S35390A_BYTE_YEAR 0
#define S35390A_BYTE_MONTH 1
#define S35390A_BYTE_DAY 2
#define S35390A_BYTE_WDAY 3
#define S35390A_BYTE_HOURS 4
#define S35390A_BYTE_MINS 5
#define S35390A_BYTE_SECS 6
/* flags for STATUS1 */
#define S35390A_FLAG_POC 0x01
#define S35390A_FLAG_BLD 0x02
#define S35390A_FLAG_INT2 0x04
#define S35390A_FLAG_24H 0x40
#define S35390A_FLAG_RESET 0x80
/*
* If either BLD or POC is set, then the chip has lost power long enough for
* the time value to become invalid.
*/
#define S35390A_LOW_VOLTAGE (S35390A_FLAG_POC | S35390A_FLAG_BLD)
/*---------------------------------------------------------------------*/
#undef DEBUG_RTC
#ifdef DEBUG_RTC
#define DEBUGR(fmt, args...) printf(fmt, ##args)
#else
#define DEBUGR(fmt, args...)
#endif
/*---------------------------------------------------------------------*/
#ifdef CONFIG_DM_RTC
#define DEV_TYPE struct udevice
#else
/* Local udevice */
struct ludevice {
u8 chip;
};
#define DEV_TYPE struct ludevice
struct ludevice dev;
#endif
#define msleep(a) udelay(a * 1000)
int lowvoltage;
static int s35392a_rtc_reset(DEV_TYPE *dev);
static int s35392a_rtc_read(DEV_TYPE *dev, u8 reg, u8 *buf, int len)
{
int ret;
#ifdef CONFIG_DM_RTC
/* TODO: we need to tweak the chip address to reg */
ret = dm_i2c_read(dev, 0, buf, len);
#else
(void)dev;
ret = i2c_read(reg, 0, -1, buf, len);
#endif
return ret;
}
static int s35392a_rtc_write(DEV_TYPE *dev, u8 reg, u8 *buf, int len)
{
int ret;
#ifdef CONFIG_DM_RTC
/* TODO: we need to tweak the chip address to reg */
ret = dm_i2c_write(dev, 0, buf, 1);
#else
(void)dev;
ret = i2c_write(reg, 0, 0, buf, len);
#endif
return ret;
}
static int s35392a_rtc_read8(DEV_TYPE *dev, unsigned int reg)
{
u8 val;
int ret;
ret = s35392a_rtc_read(dev, reg, &val, sizeof(val));
return ret < 0 ? ret : val;
}
static int s35392a_rtc_write8(DEV_TYPE *dev, unsigned int reg, int val)
{
int ret;
u8 lval = val;
ret = s35392a_rtc_write(dev, reg, &lval, sizeof(lval));
return ret < 0 ? ret : 0;
}
static int validate_time(const struct rtc_time *tm)
{
if ((tm->tm_year < 2000) || (tm->tm_year > 2099))
return -EINVAL;
if ((tm->tm_mon < 1) || (tm->tm_mon > 12))
return -EINVAL;
if ((tm->tm_mday < 1) || (tm->tm_mday > 31))
return -EINVAL;
if ((tm->tm_wday < 0) || (tm->tm_wday > 6))
return -EINVAL;
if ((tm->tm_hour < 0) || (tm->tm_hour > 23))
return -EINVAL;
if ((tm->tm_min < 0) || (tm->tm_min > 59))
return -EINVAL;
if ((tm->tm_sec < 0) || (tm->tm_sec > 59))
return -EINVAL;
return 0;
}
void s35392a_rtc_init(DEV_TYPE *dev)
{
int status;
status = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
if (status < 0)
goto error;
DEBUGR("init: S35390A_CMD_STATUS1: 0x%x\n", status);
lowvoltage = status & S35390A_LOW_VOLTAGE ? 1 : 0;
if (status & S35390A_FLAG_POC)
/*
* Do not communicate for 0.5 seconds since the power-on
* detection circuit is in operation.
*/
msleep(500);
else if (!lowvoltage)
/*
* If both POC and BLD are unset everything is fine.
*/
return;
if (lowvoltage)
printf("RTC low voltage detected\n");
if (!s35392a_rtc_reset(dev))
return;
error:
printf("Error RTC init.\n");
}
/* Get the current time from the RTC */
static int s35392a_rtc_get(DEV_TYPE *dev, struct rtc_time *tm)
{
u8 date[7];
int ret, i;
if (lowvoltage) {
DEBUGR("RTC low voltage detected\n");
return -EINVAL;
}
ret = s35392a_rtc_read(dev, S35390A_CMD_TIME1, date, sizeof(date));
if (ret < 0) {
DEBUGR("Error reading date from RTC\n");
return -EIO;
}
/* This chip returns the bits of each byte in reverse order */
for (i = 0; i < 7; ++i)
date[i] = bitrev8(date[i]);
tm->tm_sec = bcd2bin(date[S35390A_BYTE_SECS]);
tm->tm_min = bcd2bin(date[S35390A_BYTE_MINS]);
tm->tm_hour = bcd2bin(date[S35390A_BYTE_HOURS] & ~S35390A_FLAG_24H);
tm->tm_wday = bcd2bin(date[S35390A_BYTE_WDAY]);
tm->tm_mday = bcd2bin(date[S35390A_BYTE_DAY]);
tm->tm_mon = bcd2bin(date[S35390A_BYTE_MONTH]);
tm->tm_year = bcd2bin(date[S35390A_BYTE_YEAR]) + 2000;
DEBUGR("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
return 0;
}
/* Set the RTC */
static int s35392a_rtc_set(DEV_TYPE *dev, const struct rtc_time *tm)
{
int i, ret;
int status;
u8 date[7];
DEBUGR("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
ret = validate_time(tm);
if (ret < 0)
return -EINVAL;
/* We support only 24h mode */
ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
if (ret < 0)
return -EIO;
status = ret;
ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1,
status | S35390A_FLAG_24H);
if (ret < 0)
return -EIO;
date[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 2000);
date[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon);
date[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
date[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
date[S35390A_BYTE_HOURS] = bin2bcd(tm->tm_hour);
date[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
date[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
/* This chip expects the bits of each byte to be in reverse order */
for (i = 0; i < 7; ++i)
date[i] = bitrev8(date[i]);
ret = s35392a_rtc_write(dev, S35390A_CMD_TIME1, date, sizeof(date));
if (ret < 0) {
DEBUGR("Error writing date to RTC\n");
return -EIO;
}
/* Now we have time. Reset the low voltage status */
lowvoltage = 0;
return 0;
}
/* Reset the RTC. */
static int s35392a_rtc_reset(DEV_TYPE *dev)
{
int buf;
int ret;
unsigned int initcount = 0;
buf = S35390A_FLAG_RESET;
initialize:
ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1, buf);
if (ret < 0)
return -EIO;
ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
if (ret < 0)
return -EIO;
buf = ret;
if (!lowvoltage)
lowvoltage = buf & S35390A_LOW_VOLTAGE ? 1 : 0;
if (buf & S35390A_LOW_VOLTAGE) {
/* Try up to five times to reset the chip */
if (initcount < 5) {
++initcount;
goto initialize;
} else {
return -EIO;
}
}
return 0;
}
#ifndef CONFIG_DM_RTC
int rtc_get(struct rtc_time *tm)
{
return s35392a_rtc_get(&dev, tm);
}
int rtc_set(struct rtc_time *tm)
{
return s35392a_rtc_set(&dev, tm);
}
void rtc_reset(void)
{
s35392a_rtc_reset(&dev);
}
void rtc_init(void)
{
s35392a_rtc_init(&dev);
}
#else
static int s35392a_probe(struct udevice *dev)
{
s35392a_rtc_init(dev);
return 0;
}
static const struct rtc_ops s35392a_rtc_ops = {
.get = s35392a_rtc_get,
.set = s35392a_rtc_set,
.read8 = s35392a_rtc_read8,
.write8 = s35392a_rtc_write8,
.reset = s35392a_rtc_reset,
};
static const struct udevice_id s35392a_rtc_ids[] = {
{ .compatible = "sii,s35392a-rtc" },
{ }
};
U_BOOT_DRIVER(s35392a_rtc) = {
.name = "s35392a_rtc",
.id = UCLASS_RTC,
.probe = s35392a_probe,
.of_match = s35392a_rtc_ids,
.ops = &s35392a_rtc_ops,
};
#endif
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