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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Driver for Epson RTC-9701JE4 *5 * Copyright (C) 2008 Magnus Damm6 *7 * Based on rtc-max6902.c8 *9 * Copyright (C) 2006 8D Technologies inc.10 * Copyright (C) 2004 Compulab Ltd.11 */12 13#include <linux/module.h>14#include <linux/kernel.h>15#include <linux/platform_device.h>16#include <linux/device.h>17#include <linux/init.h>18#include <linux/rtc.h>19#include <linux/spi/spi.h>20#include <linux/bcd.h>21#include <linux/delay.h>22#include <linux/bitops.h>23 24#define RSECCNT 0x00 /* Second Counter */25#define RMINCNT 0x01 /* Minute Counter */26#define RHRCNT 0x02 /* Hour Counter */27#define RWKCNT 0x03 /* Week Counter */28#define RDAYCNT 0x04 /* Day Counter */29#define RMONCNT 0x05 /* Month Counter */30#define RYRCNT 0x06 /* Year Counter */31#define R100CNT 0x07 /* Y100 Counter */32#define RMINAR 0x08 /* Minute Alarm */33#define RHRAR 0x09 /* Hour Alarm */34#define RWKAR 0x0a /* Week/Day Alarm */35#define RTIMCNT 0x0c /* Interval Timer */36#define REXT 0x0d /* Extension Register */37#define RFLAG 0x0e /* RTC Flag Register */38#define RCR 0x0f /* RTC Control Register */39 40static int write_reg(struct device *dev, int address, unsigned char data)41{42 struct spi_device *spi = to_spi_device(dev);43 unsigned char buf[2];44 45 buf[0] = address & 0x7f;46 buf[1] = data;47 48 return spi_write(spi, buf, ARRAY_SIZE(buf));49}50 51static int read_regs(struct device *dev, unsigned char *regs, int no_regs)52{53 struct spi_device *spi = to_spi_device(dev);54 u8 txbuf[1], rxbuf[1];55 int k, ret;56 57 ret = 0;58 59 for (k = 0; ret == 0 && k < no_regs; k++) {60 txbuf[0] = 0x80 | regs[k];61 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);62 regs[k] = rxbuf[0];63 }64 65 return ret;66}67 68static int r9701_get_datetime(struct device *dev, struct rtc_time *dt)69{70 int ret;71 unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,72 RDAYCNT, RMONCNT, RYRCNT };73 74 ret = read_regs(dev, buf, ARRAY_SIZE(buf));75 if (ret)76 return ret;77 78 dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */79 dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */80 dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */81 82 dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */83 dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */84 dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */85 86 return 0;87}88 89static int r9701_set_datetime(struct device *dev, struct rtc_time *dt)90{91 int ret;92 93 ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));94 ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));95 ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));96 ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));97 ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));98 ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));99 100 return ret;101}102 103static const struct rtc_class_ops r9701_rtc_ops = {104 .read_time = r9701_get_datetime,105 .set_time = r9701_set_datetime,106};107 108static int r9701_probe(struct spi_device *spi)109{110 struct rtc_device *rtc;111 unsigned char tmp;112 int res;113 114 tmp = R100CNT;115 res = read_regs(&spi->dev, &tmp, 1);116 if (res || tmp != 0x20) {117 dev_err(&spi->dev, "cannot read RTC register\n");118 return -ENODEV;119 }120 121 rtc = devm_rtc_allocate_device(&spi->dev);122 if (IS_ERR(rtc))123 return PTR_ERR(rtc);124 125 spi_set_drvdata(spi, rtc);126 rtc->ops = &r9701_rtc_ops;127 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;128 rtc->range_max = RTC_TIMESTAMP_END_2099;129 130 return devm_rtc_register_device(rtc);131}132 133static struct spi_driver r9701_driver = {134 .driver = {135 .name = "rtc-r9701",136 },137 .probe = r9701_probe,138};139 140module_spi_driver(r9701_driver);141 142MODULE_DESCRIPTION("r9701 spi RTC driver");143MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");144MODULE_LICENSE("GPL");145MODULE_ALIAS("spi:rtc-r9701");146