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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * A SPI driver for the Ricoh RS5C348 RTC4 *5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>6 *7 * The board specific init code should provide characteristics of this8 * device:9 * Mode 1 (High-Active, Shift-Then-Sample), High Avtive CS10 */11 12#include <linux/bcd.h>13#include <linux/delay.h>14#include <linux/device.h>15#include <linux/errno.h>16#include <linux/init.h>17#include <linux/kernel.h>18#include <linux/string.h>19#include <linux/slab.h>20#include <linux/rtc.h>21#include <linux/workqueue.h>22#include <linux/spi/spi.h>23#include <linux/module.h>24 25#define RS5C348_REG_SECS 026#define RS5C348_REG_MINS 127#define RS5C348_REG_HOURS 228#define RS5C348_REG_WDAY 329#define RS5C348_REG_DAY 430#define RS5C348_REG_MONTH 531#define RS5C348_REG_YEAR 632#define RS5C348_REG_CTL1 1433#define RS5C348_REG_CTL2 1534 35#define RS5C348_SECS_MASK 0x7f36#define RS5C348_MINS_MASK 0x7f37#define RS5C348_HOURS_MASK 0x3f38#define RS5C348_WDAY_MASK 0x0339#define RS5C348_DAY_MASK 0x3f40#define RS5C348_MONTH_MASK 0x1f41 42#define RS5C348_BIT_PM 0x20 /* REG_HOURS */43#define RS5C348_BIT_Y2K 0x80 /* REG_MONTH */44#define RS5C348_BIT_24H 0x20 /* REG_CTL1 */45#define RS5C348_BIT_XSTP 0x10 /* REG_CTL2 */46#define RS5C348_BIT_VDET 0x40 /* REG_CTL2 */47 48#define RS5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */49#define RS5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */50#define RS5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */51#define RS5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */52 53struct rs5c348_plat_data {54 struct rtc_device *rtc;55 int rtc_24h;56};57 58static int59rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm)60{61 struct spi_device *spi = to_spi_device(dev);62 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev);63 u8 txbuf[5+7], *txp;64 int ret;65 66 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));67 if (ret < 0)68 return ret;69 if (ret & RS5C348_BIT_XSTP) {70 txbuf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2);71 txbuf[1] = 0;72 ret = spi_write_then_read(spi, txbuf, 2, NULL, 0);73 if (ret < 0)74 return ret;75 }76 77 /* Transfer 5 bytes before writing SEC. This gives 31us for carry. */78 txp = txbuf;79 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */80 txbuf[1] = 0; /* dummy */81 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */82 txbuf[3] = 0; /* dummy */83 txbuf[4] = RS5C348_CMD_MW(RS5C348_REG_SECS); /* cmd, sec, ... */84 txp = &txbuf[5];85 txp[RS5C348_REG_SECS] = bin2bcd(tm->tm_sec);86 txp[RS5C348_REG_MINS] = bin2bcd(tm->tm_min);87 if (pdata->rtc_24h) {88 txp[RS5C348_REG_HOURS] = bin2bcd(tm->tm_hour);89 } else {90 /* hour 0 is AM12, noon is PM12 */91 txp[RS5C348_REG_HOURS] = bin2bcd((tm->tm_hour + 11) % 12 + 1) |92 (tm->tm_hour >= 12 ? RS5C348_BIT_PM : 0);93 }94 txp[RS5C348_REG_WDAY] = bin2bcd(tm->tm_wday);95 txp[RS5C348_REG_DAY] = bin2bcd(tm->tm_mday);96 txp[RS5C348_REG_MONTH] = bin2bcd(tm->tm_mon + 1) |97 (tm->tm_year >= 100 ? RS5C348_BIT_Y2K : 0);98 txp[RS5C348_REG_YEAR] = bin2bcd(tm->tm_year % 100);99 /* write in one transfer to avoid data inconsistency */100 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), NULL, 0);101 udelay(62); /* Tcsr 62us */102 return ret;103}104 105static int106rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm)107{108 struct spi_device *spi = to_spi_device(dev);109 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev);110 u8 txbuf[5], rxbuf[7];111 int ret;112 113 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));114 if (ret < 0)115 return ret;116 if (ret & RS5C348_BIT_VDET)117 dev_warn(&spi->dev, "voltage-low detected.\n");118 if (ret & RS5C348_BIT_XSTP) {119 dev_warn(&spi->dev, "oscillator-stop detected.\n");120 return -EINVAL;121 }122 123 /* Transfer 5 byte befores reading SEC. This gives 31us for carry. */124 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */125 txbuf[1] = 0; /* dummy */126 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */127 txbuf[3] = 0; /* dummy */128 txbuf[4] = RS5C348_CMD_MR(RS5C348_REG_SECS); /* cmd, sec, ... */129 130 /* read in one transfer to avoid data inconsistency */131 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),132 rxbuf, sizeof(rxbuf));133 udelay(62); /* Tcsr 62us */134 if (ret < 0)135 return ret;136 137 tm->tm_sec = bcd2bin(rxbuf[RS5C348_REG_SECS] & RS5C348_SECS_MASK);138 tm->tm_min = bcd2bin(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK);139 tm->tm_hour = bcd2bin(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK);140 if (!pdata->rtc_24h) {141 if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM) {142 tm->tm_hour -= 20;143 tm->tm_hour %= 12;144 tm->tm_hour += 12;145 } else146 tm->tm_hour %= 12;147 }148 tm->tm_wday = bcd2bin(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK);149 tm->tm_mday = bcd2bin(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK);150 tm->tm_mon =151 bcd2bin(rxbuf[RS5C348_REG_MONTH] & RS5C348_MONTH_MASK) - 1;152 /* year is 1900 + tm->tm_year */153 tm->tm_year = bcd2bin(rxbuf[RS5C348_REG_YEAR]) +154 ((rxbuf[RS5C348_REG_MONTH] & RS5C348_BIT_Y2K) ? 100 : 0);155 156 return 0;157}158 159static const struct rtc_class_ops rs5c348_rtc_ops = {160 .read_time = rs5c348_rtc_read_time,161 .set_time = rs5c348_rtc_set_time,162};163 164static int rs5c348_probe(struct spi_device *spi)165{166 int ret;167 struct rtc_device *rtc;168 struct rs5c348_plat_data *pdata;169 170 pdata = devm_kzalloc(&spi->dev, sizeof(struct rs5c348_plat_data),171 GFP_KERNEL);172 if (!pdata)173 return -ENOMEM;174 spi->dev.platform_data = pdata;175 176 /* Check D7 of SECOND register */177 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_SECS));178 if (ret < 0 || (ret & 0x80)) {179 dev_err(&spi->dev, "not found.\n");180 return ret;181 }182 183 dev_info(&spi->dev, "spiclk %u KHz.\n",184 (spi->max_speed_hz + 500) / 1000);185 186 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1));187 if (ret < 0)188 return ret;189 if (ret & RS5C348_BIT_24H)190 pdata->rtc_24h = 1;191 192 rtc = devm_rtc_allocate_device(&spi->dev);193 if (IS_ERR(rtc))194 return PTR_ERR(rtc);195 196 pdata->rtc = rtc;197 198 rtc->ops = &rs5c348_rtc_ops;199 200 return devm_rtc_register_device(rtc);201}202 203static struct spi_driver rs5c348_driver = {204 .driver = {205 .name = "rtc-rs5c348",206 },207 .probe = rs5c348_probe,208};209 210module_spi_driver(rs5c348_driver);211 212MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");213MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver");214MODULE_LICENSE("GPL");215MODULE_ALIAS("spi:rtc-rs5c348");216