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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 | /* * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC * * Copyright (C) 2008 Mercury IMC Ltd * Written by Mark Jackson <mpfj@mimc.co.uk> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * NOTE: Currently this driver only supports the bare minimum for read * and write the RTC. The extra features provided by the chip family * (alarms, trickle charger, different control registers) are unavailable. */ #include <linux/init.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/rtc.h> #include <linux/spi/spi.h> #include <linux/bcd.h> #include <linux/slab.h> #define DS1390_REG_100THS 0x00 #define DS1390_REG_SECONDS 0x01 #define DS1390_REG_MINUTES 0x02 #define DS1390_REG_HOURS 0x03 #define DS1390_REG_DAY 0x04 #define DS1390_REG_DATE 0x05 #define DS1390_REG_MONTH_CENT 0x06 #define DS1390_REG_YEAR 0x07 #define DS1390_REG_ALARM_100THS 0x08 #define DS1390_REG_ALARM_SECONDS 0x09 #define DS1390_REG_ALARM_MINUTES 0x0A #define DS1390_REG_ALARM_HOURS 0x0B #define DS1390_REG_ALARM_DAY_DATE 0x0C #define DS1390_REG_CONTROL 0x0D #define DS1390_REG_STATUS 0x0E #define DS1390_REG_TRICKLE 0x0F struct ds1390 { struct rtc_device *rtc; u8 txrx_buf[9]; /* cmd + 8 registers */ }; static int ds1390_get_reg(struct device *dev, unsigned char address, unsigned char *data) { struct spi_device *spi = to_spi_device(dev); struct ds1390 *chip = dev_get_drvdata(dev); int status; if (!data) return -EINVAL; /* Clear MSB to indicate read */ chip->txrx_buf[0] = address & 0x7f; /* do the i/o */ status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1); if (status != 0) return status; *data = chip->txrx_buf[1]; return 0; } static int ds1390_read_time(struct device *dev, struct rtc_time *dt) { struct spi_device *spi = to_spi_device(dev); struct ds1390 *chip = dev_get_drvdata(dev); int status; /* build the message */ chip->txrx_buf[0] = DS1390_REG_SECONDS; /* do the i/o */ status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8); if (status != 0) return status; /* The chip sends data in this order: * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */ dt->tm_sec = bcd2bin(chip->txrx_buf[0]); dt->tm_min = bcd2bin(chip->txrx_buf[1]); dt->tm_hour = bcd2bin(chip->txrx_buf[2]); dt->tm_wday = bcd2bin(chip->txrx_buf[3]); dt->tm_mday = bcd2bin(chip->txrx_buf[4]); /* mask off century bit */ dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1; /* adjust for century bit */ dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0); return rtc_valid_tm(dt); } static int ds1390_set_time(struct device *dev, struct rtc_time *dt) { struct spi_device *spi = to_spi_device(dev); struct ds1390 *chip = dev_get_drvdata(dev); /* build the message */ chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80; chip->txrx_buf[1] = bin2bcd(dt->tm_sec); chip->txrx_buf[2] = bin2bcd(dt->tm_min); chip->txrx_buf[3] = bin2bcd(dt->tm_hour); chip->txrx_buf[4] = bin2bcd(dt->tm_wday); chip->txrx_buf[5] = bin2bcd(dt->tm_mday); chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) | ((dt->tm_year > 99) ? 0x80 : 0x00); chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100); /* do the i/o */ return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0); } static const struct rtc_class_ops ds1390_rtc_ops = { .read_time = ds1390_read_time, .set_time = ds1390_set_time, }; static int ds1390_probe(struct spi_device *spi) { unsigned char tmp; struct ds1390 *chip; int res; spi->mode = SPI_MODE_3; spi->bits_per_word = 8; spi_setup(spi); chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL); if (!chip) { dev_err(&spi->dev, "unable to allocate device memory\n"); return -ENOMEM; } spi_set_drvdata(spi, chip); res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp); if (res != 0) { dev_err(&spi->dev, "unable to read device\n"); return res; } chip->rtc = devm_rtc_device_register(&spi->dev, "ds1390", &ds1390_rtc_ops, THIS_MODULE); if (IS_ERR(chip->rtc)) { dev_err(&spi->dev, "unable to register device\n"); res = PTR_ERR(chip->rtc); } return res; } static struct spi_driver ds1390_driver = { .driver = { .name = "rtc-ds1390", .owner = THIS_MODULE, }, .probe = ds1390_probe, }; module_spi_driver(ds1390_driver); MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver"); MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("spi:rtc-ds1390"); |