^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /* drivers/rtc/rtc-max6902.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * Copyright (C) 2006 8D Technologies inc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 2004 Compulab Ltd.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Driver for MAX6902 spi RTC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/platform_device.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/rtc.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/spi/spi.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/bcd.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #define MAX6902_REG_SECONDS 0x01
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #define MAX6902_REG_MINUTES 0x03
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #define MAX6902_REG_HOURS 0x05
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #define MAX6902_REG_DATE 0x07
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #define MAX6902_REG_MONTH 0x09
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #define MAX6902_REG_DAY 0x0B
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) #define MAX6902_REG_YEAR 0x0D
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #define MAX6902_REG_CONTROL 0x0F
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #define MAX6902_REG_CENTURY 0x13
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) static int max6902_set_reg(struct device *dev, unsigned char address,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) unsigned char data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) struct spi_device *spi = to_spi_device(dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) unsigned char buf[2];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) /* MSB must be '0' to write */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) buf[0] = address & 0x7f;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) buf[1] = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) return spi_write_then_read(spi, buf, 2, NULL, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) static int max6902_get_reg(struct device *dev, unsigned char address,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) unsigned char *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) struct spi_device *spi = to_spi_device(dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) /* Set MSB to indicate read */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) *data = address | 0x80;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) return spi_write_then_read(spi, data, 1, data, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) static int max6902_read_time(struct device *dev, struct rtc_time *dt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) int err, century;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) struct spi_device *spi = to_spi_device(dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) unsigned char buf[8];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) buf[0] = 0xbf; /* Burst read */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) err = spi_write_then_read(spi, buf, 1, buf, 8);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) if (err != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) /* The chip sends data in this order:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * Seconds, Minutes, Hours, Date, Month, Day, Year */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) dt->tm_sec = bcd2bin(buf[0]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) dt->tm_min = bcd2bin(buf[1]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) dt->tm_hour = bcd2bin(buf[2]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) dt->tm_mday = bcd2bin(buf[3]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) dt->tm_mon = bcd2bin(buf[4]) - 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) dt->tm_wday = bcd2bin(buf[5]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) dt->tm_year = bcd2bin(buf[6]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) /* Read century */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &buf[0]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) if (err != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) century = bcd2bin(buf[0]) * 100;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) dt->tm_year += century;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) dt->tm_year -= 1900;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) static int max6902_set_time(struct device *dev, struct rtc_time *dt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) dt->tm_year = dt->tm_year + 1900;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) /* Remove write protection */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) max6902_set_reg(dev, MAX6902_REG_CONTROL, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) max6902_set_reg(dev, MAX6902_REG_SECONDS, bin2bcd(dt->tm_sec));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) max6902_set_reg(dev, MAX6902_REG_MINUTES, bin2bcd(dt->tm_min));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) max6902_set_reg(dev, MAX6902_REG_HOURS, bin2bcd(dt->tm_hour));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) max6902_set_reg(dev, MAX6902_REG_DATE, bin2bcd(dt->tm_mday));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) max6902_set_reg(dev, MAX6902_REG_MONTH, bin2bcd(dt->tm_mon + 1));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) max6902_set_reg(dev, MAX6902_REG_DAY, bin2bcd(dt->tm_wday));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) max6902_set_reg(dev, MAX6902_REG_YEAR, bin2bcd(dt->tm_year % 100));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) max6902_set_reg(dev, MAX6902_REG_CENTURY, bin2bcd(dt->tm_year / 100));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) /* Compulab used a delay here. However, the datasheet
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) * does not mention a delay being required anywhere... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) /* delay(2000); */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) /* Write protect */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) max6902_set_reg(dev, MAX6902_REG_CONTROL, 0x80);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) static const struct rtc_class_ops max6902_rtc_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) .read_time = max6902_read_time,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) .set_time = max6902_set_time,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) static int max6902_probe(struct spi_device *spi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) struct rtc_device *rtc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) unsigned char tmp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) int res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) spi->mode = SPI_MODE_3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) spi->bits_per_word = 8;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) spi_setup(spi);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) if (res != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) rtc = devm_rtc_device_register(&spi->dev, "max6902",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) &max6902_rtc_ops, THIS_MODULE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) if (IS_ERR(rtc))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) return PTR_ERR(rtc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) spi_set_drvdata(spi, rtc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) static struct spi_driver max6902_driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) .driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) .name = "rtc-max6902",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) .probe = max6902_probe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) module_spi_driver(max6902_driver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) MODULE_DESCRIPTION("max6902 spi RTC driver");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) MODULE_AUTHOR("Raphael Assenat");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) MODULE_LICENSE("GPL");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) MODULE_ALIAS("spi:rtc-max6902");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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