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1// SPDX-License-Identifier: GPL-2.0-only2/* drivers/rtc/rtc-rx4581.c3 *4 * written by Torben Hohn <torbenh@linutronix.de>5 *6 * Based on:7 * drivers/rtc/rtc-max6902.c8 *9 * Copyright (C) 2006 8D Technologies inc.10 * Copyright (C) 2004 Compulab Ltd.11 *12 * Driver for MAX6902 spi RTC13 *14 * and based on:15 * drivers/rtc/rtc-rx8581.c16 *17 * An I2C driver for the Epson RX8581 RTC18 *19 * Author: Martyn Welch <martyn.welch@ge.com>20 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.21 *22 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)23 * Copyright 2005-06 Tower Technologies24 */25 26#include <linux/module.h>27#include <linux/kernel.h>28#include <linux/platform_device.h>29#include <linux/init.h>30#include <linux/rtc.h>31#include <linux/spi/spi.h>32#include <linux/bcd.h>33 34#define RX4581_REG_SC 0x00 /* Second in BCD */35#define RX4581_REG_MN 0x01 /* Minute in BCD */36#define RX4581_REG_HR 0x02 /* Hour in BCD */37#define RX4581_REG_DW 0x03 /* Day of Week */38#define RX4581_REG_DM 0x04 /* Day of Month in BCD */39#define RX4581_REG_MO 0x05 /* Month in BCD */40#define RX4581_REG_YR 0x06 /* Year in BCD */41#define RX4581_REG_RAM 0x07 /* RAM */42#define RX4581_REG_AMN 0x08 /* Alarm Min in BCD*/43#define RX4581_REG_AHR 0x09 /* Alarm Hour in BCD */44#define RX4581_REG_ADM 0x0A45#define RX4581_REG_ADW 0x0A46#define RX4581_REG_TMR0 0x0B47#define RX4581_REG_TMR1 0x0C48#define RX4581_REG_EXT 0x0D /* Extension Register */49#define RX4581_REG_FLAG 0x0E /* Flag Register */50#define RX4581_REG_CTRL 0x0F /* Control Register */51 52 53/* Flag Register bit definitions */54#define RX4581_FLAG_UF 0x20 /* Update */55#define RX4581_FLAG_TF 0x10 /* Timer */56#define RX4581_FLAG_AF 0x08 /* Alarm */57#define RX4581_FLAG_VLF 0x02 /* Voltage Low */58 59/* Control Register bit definitions */60#define RX4581_CTRL_UIE 0x20 /* Update Interrupt Enable */61#define RX4581_CTRL_TIE 0x10 /* Timer Interrupt Enable */62#define RX4581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */63#define RX4581_CTRL_STOP 0x02 /* STOP bit */64#define RX4581_CTRL_RESET 0x01 /* RESET bit */65 66static int rx4581_set_reg(struct device *dev, unsigned char address,67 unsigned char data)68{69 struct spi_device *spi = to_spi_device(dev);70 unsigned char buf[2];71 72 /* high nibble must be '0' to write */73 buf[0] = address & 0x0f;74 buf[1] = data;75 76 return spi_write_then_read(spi, buf, 2, NULL, 0);77}78 79static int rx4581_get_reg(struct device *dev, unsigned char address,80 unsigned char *data)81{82 struct spi_device *spi = to_spi_device(dev);83 84 /* Set MSB to indicate read */85 *data = address | 0x80;86 87 return spi_write_then_read(spi, data, 1, data, 1);88}89 90/*91 * In the routines that deal directly with the rx8581 hardware, we use92 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.93 */94static int rx4581_get_datetime(struct device *dev, struct rtc_time *tm)95{96 struct spi_device *spi = to_spi_device(dev);97 unsigned char date[7];98 unsigned char data;99 int err;100 101 /* First we ensure that the "update flag" is not set, we read the102 * time and date then re-read the "update flag". If the update flag103 * has been set, we know that the time has changed during the read so104 * we repeat the whole process again.105 */106 err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);107 if (err != 0) {108 dev_err(dev, "Unable to read device flags\n");109 return -EIO;110 }111 112 do {113 /* If update flag set, clear it */114 if (data & RX4581_FLAG_UF) {115 err = rx4581_set_reg(dev,116 RX4581_REG_FLAG, (data & ~RX4581_FLAG_UF));117 if (err != 0) {118 dev_err(dev, "Unable to write device "119 "flags\n");120 return -EIO;121 }122 }123 124 /* Now read time and date */125 date[0] = 0x80;126 err = spi_write_then_read(spi, date, 1, date, 7);127 if (err < 0) {128 dev_err(dev, "Unable to read date\n");129 return -EIO;130 }131 132 /* Check flag register */133 err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);134 if (err != 0) {135 dev_err(dev, "Unable to read device flags\n");136 return -EIO;137 }138 } while (data & RX4581_FLAG_UF);139 140 if (data & RX4581_FLAG_VLF)141 dev_info(dev,142 "low voltage detected, date/time is not reliable.\n");143 144 dev_dbg(dev,145 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "146 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n",147 __func__,148 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);149 150 tm->tm_sec = bcd2bin(date[RX4581_REG_SC] & 0x7F);151 tm->tm_min = bcd2bin(date[RX4581_REG_MN] & 0x7F);152 tm->tm_hour = bcd2bin(date[RX4581_REG_HR] & 0x3F); /* rtc hr 0-23 */153 tm->tm_wday = ilog2(date[RX4581_REG_DW] & 0x7F);154 tm->tm_mday = bcd2bin(date[RX4581_REG_DM] & 0x3F);155 tm->tm_mon = bcd2bin(date[RX4581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */156 tm->tm_year = bcd2bin(date[RX4581_REG_YR]);157 if (tm->tm_year < 70)158 tm->tm_year += 100; /* assume we are in 1970...2069 */159 160 161 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "162 "mday=%d, mon=%d, year=%d, wday=%d\n",163 __func__,164 tm->tm_sec, tm->tm_min, tm->tm_hour,165 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);166 167 return 0;168}169 170static int rx4581_set_datetime(struct device *dev, struct rtc_time *tm)171{172 struct spi_device *spi = to_spi_device(dev);173 int err;174 unsigned char buf[8], data;175 176 dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "177 "mday=%d, mon=%d, year=%d, wday=%d\n",178 __func__,179 tm->tm_sec, tm->tm_min, tm->tm_hour,180 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);181 182 buf[0] = 0x00;183 /* hours, minutes and seconds */184 buf[RX4581_REG_SC+1] = bin2bcd(tm->tm_sec);185 buf[RX4581_REG_MN+1] = bin2bcd(tm->tm_min);186 buf[RX4581_REG_HR+1] = bin2bcd(tm->tm_hour);187 188 buf[RX4581_REG_DM+1] = bin2bcd(tm->tm_mday);189 190 /* month, 1 - 12 */191 buf[RX4581_REG_MO+1] = bin2bcd(tm->tm_mon + 1);192 193 /* year and century */194 buf[RX4581_REG_YR+1] = bin2bcd(tm->tm_year % 100);195 buf[RX4581_REG_DW+1] = (0x1 << tm->tm_wday);196 197 /* Stop the clock */198 err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data);199 if (err != 0) {200 dev_err(dev, "Unable to read control register\n");201 return -EIO;202 }203 204 err = rx4581_set_reg(dev, RX4581_REG_CTRL,205 (data | RX4581_CTRL_STOP));206 if (err != 0) {207 dev_err(dev, "Unable to write control register\n");208 return -EIO;209 }210 211 /* write register's data */212 err = spi_write_then_read(spi, buf, 8, NULL, 0);213 if (err != 0) {214 dev_err(dev, "Unable to write to date registers\n");215 return -EIO;216 }217 218 /* get VLF and clear it */219 err = rx4581_get_reg(dev, RX4581_REG_FLAG, &data);220 if (err != 0) {221 dev_err(dev, "Unable to read flag register\n");222 return -EIO;223 }224 225 err = rx4581_set_reg(dev, RX4581_REG_FLAG,226 (data & ~(RX4581_FLAG_VLF)));227 if (err != 0) {228 dev_err(dev, "Unable to write flag register\n");229 return -EIO;230 }231 232 /* Restart the clock */233 err = rx4581_get_reg(dev, RX4581_REG_CTRL, &data);234 if (err != 0) {235 dev_err(dev, "Unable to read control register\n");236 return -EIO;237 }238 239 err = rx4581_set_reg(dev, RX4581_REG_CTRL,240 (data & ~(RX4581_CTRL_STOP)));241 if (err != 0) {242 dev_err(dev, "Unable to write control register\n");243 return -EIO;244 }245 246 return 0;247}248 249static const struct rtc_class_ops rx4581_rtc_ops = {250 .read_time = rx4581_get_datetime,251 .set_time = rx4581_set_datetime,252};253 254static int rx4581_probe(struct spi_device *spi)255{256 struct rtc_device *rtc;257 unsigned char tmp;258 int res;259 260 res = rx4581_get_reg(&spi->dev, RX4581_REG_SC, &tmp);261 if (res != 0)262 return res;263 264 rtc = devm_rtc_device_register(&spi->dev, "rx4581",265 &rx4581_rtc_ops, THIS_MODULE);266 if (IS_ERR(rtc))267 return PTR_ERR(rtc);268 269 spi_set_drvdata(spi, rtc);270 return 0;271}272 273static const struct spi_device_id rx4581_id[] = {274 { "rx4581", 0 },275 { }276};277MODULE_DEVICE_TABLE(spi, rx4581_id);278 279static struct spi_driver rx4581_driver = {280 .driver = {281 .name = "rtc-rx4581",282 },283 .probe = rx4581_probe,284 .id_table = rx4581_id,285};286 287module_spi_driver(rx4581_driver);288 289MODULE_DESCRIPTION("rx4581 spi RTC driver");290MODULE_AUTHOR("Torben Hohn");291MODULE_LICENSE("GPL");292MODULE_ALIAS("spi:rtc-rx4581");293