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