1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2617b26a0SRaghavendra Ganiga /* rtc-ds1347.c 3617b26a0SRaghavendra Ganiga * 4617b26a0SRaghavendra Ganiga * Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible 5617b26a0SRaghavendra Ganiga * Real Time Clock 6617b26a0SRaghavendra Ganiga * 7617b26a0SRaghavendra Ganiga * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com> 8617b26a0SRaghavendra Ganiga */ 9617b26a0SRaghavendra Ganiga 10617b26a0SRaghavendra Ganiga #include <linux/init.h> 11617b26a0SRaghavendra Ganiga #include <linux/module.h> 12617b26a0SRaghavendra Ganiga #include <linux/device.h> 13617b26a0SRaghavendra Ganiga #include <linux/platform_device.h> 14617b26a0SRaghavendra Ganiga #include <linux/rtc.h> 15617b26a0SRaghavendra Ganiga #include <linux/spi/spi.h> 16617b26a0SRaghavendra Ganiga #include <linux/bcd.h> 17ee85bb5bSRaghavendra Ganiga #include <linux/regmap.h> 18617b26a0SRaghavendra Ganiga 19617b26a0SRaghavendra Ganiga /* Registers in ds1347 rtc */ 20617b26a0SRaghavendra Ganiga 21617b26a0SRaghavendra Ganiga #define DS1347_SECONDS_REG 0x01 22617b26a0SRaghavendra Ganiga #define DS1347_MINUTES_REG 0x03 23617b26a0SRaghavendra Ganiga #define DS1347_HOURS_REG 0x05 24617b26a0SRaghavendra Ganiga #define DS1347_DATE_REG 0x07 25617b26a0SRaghavendra Ganiga #define DS1347_MONTH_REG 0x09 26617b26a0SRaghavendra Ganiga #define DS1347_DAY_REG 0x0B 27617b26a0SRaghavendra Ganiga #define DS1347_YEAR_REG 0x0D 28617b26a0SRaghavendra Ganiga #define DS1347_CONTROL_REG 0x0F 29147dae76SAlexandre Belloni #define DS1347_CENTURY_REG 0x13 30617b26a0SRaghavendra Ganiga #define DS1347_STATUS_REG 0x17 31617b26a0SRaghavendra Ganiga #define DS1347_CLOCK_BURST 0x3F 32617b26a0SRaghavendra Ganiga 33860c45b5SAlexandre Belloni #define DS1347_WP_BIT BIT(7) 34860c45b5SAlexandre Belloni 35d9dcfa5fSAlexandre Belloni #define DS1347_NEOSC_BIT BIT(7) 36d9dcfa5fSAlexandre Belloni #define DS1347_OSF_BIT BIT(2) 37d9dcfa5fSAlexandre Belloni 38ee85bb5bSRaghavendra Ganiga static const struct regmap_range ds1347_ranges[] = { 39617b26a0SRaghavendra Ganiga { 40ee85bb5bSRaghavendra Ganiga .range_min = DS1347_SECONDS_REG, 41ee85bb5bSRaghavendra Ganiga .range_max = DS1347_STATUS_REG, 42ee85bb5bSRaghavendra Ganiga }, 43ee85bb5bSRaghavendra Ganiga }; 44617b26a0SRaghavendra Ganiga 45ee85bb5bSRaghavendra Ganiga static const struct regmap_access_table ds1347_access_table = { 46ee85bb5bSRaghavendra Ganiga .yes_ranges = ds1347_ranges, 47ee85bb5bSRaghavendra Ganiga .n_yes_ranges = ARRAY_SIZE(ds1347_ranges), 48ee85bb5bSRaghavendra Ganiga }; 49617b26a0SRaghavendra Ganiga 50617b26a0SRaghavendra Ganiga static int ds1347_read_time(struct device *dev, struct rtc_time *dt) 51617b26a0SRaghavendra Ganiga { 52ff7f9e05SAlexandre Belloni struct regmap *map = dev_get_drvdata(dev); 53147dae76SAlexandre Belloni unsigned int status, century, secs; 54617b26a0SRaghavendra Ganiga unsigned char buf[8]; 55147dae76SAlexandre Belloni int err; 56617b26a0SRaghavendra Ganiga 57d9dcfa5fSAlexandre Belloni err = regmap_read(map, DS1347_STATUS_REG, &status); 58d9dcfa5fSAlexandre Belloni if (err) 59d9dcfa5fSAlexandre Belloni return err; 60d9dcfa5fSAlexandre Belloni 61d9dcfa5fSAlexandre Belloni if (status & DS1347_OSF_BIT) 62d9dcfa5fSAlexandre Belloni return -EINVAL; 63d9dcfa5fSAlexandre Belloni 64147dae76SAlexandre Belloni do { 65ee85bb5bSRaghavendra Ganiga err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8); 66617b26a0SRaghavendra Ganiga if (err) 67617b26a0SRaghavendra Ganiga return err; 68617b26a0SRaghavendra Ganiga 69147dae76SAlexandre Belloni err = regmap_read(map, DS1347_CENTURY_REG, ¢ury); 70147dae76SAlexandre Belloni if (err) 71147dae76SAlexandre Belloni return err; 72147dae76SAlexandre Belloni 73147dae76SAlexandre Belloni err = regmap_read(map, DS1347_SECONDS_REG, &secs); 74147dae76SAlexandre Belloni if (err) 75147dae76SAlexandre Belloni return err; 76147dae76SAlexandre Belloni } while (buf[0] != secs); 77147dae76SAlexandre Belloni 78617b26a0SRaghavendra Ganiga dt->tm_sec = bcd2bin(buf[0]); 79088443c7SAlexandre Belloni dt->tm_min = bcd2bin(buf[1] & 0x7f); 80617b26a0SRaghavendra Ganiga dt->tm_hour = bcd2bin(buf[2] & 0x3F); 81617b26a0SRaghavendra Ganiga dt->tm_mday = bcd2bin(buf[3]); 82617b26a0SRaghavendra Ganiga dt->tm_mon = bcd2bin(buf[4]) - 1; 83617b26a0SRaghavendra Ganiga dt->tm_wday = bcd2bin(buf[5]) - 1; 84147dae76SAlexandre Belloni dt->tm_year = (bcd2bin(century) * 100) + bcd2bin(buf[6]) - 1900; 85617b26a0SRaghavendra Ganiga 8622652ba7SAlexandre Belloni return 0; 87617b26a0SRaghavendra Ganiga } 88617b26a0SRaghavendra Ganiga 89617b26a0SRaghavendra Ganiga static int ds1347_set_time(struct device *dev, struct rtc_time *dt) 90617b26a0SRaghavendra Ganiga { 91ff7f9e05SAlexandre Belloni struct regmap *map = dev_get_drvdata(dev); 92147dae76SAlexandre Belloni unsigned int century; 93ee85bb5bSRaghavendra Ganiga unsigned char buf[8]; 94d9dcfa5fSAlexandre Belloni int err; 95d9dcfa5fSAlexandre Belloni 96d9dcfa5fSAlexandre Belloni err = regmap_update_bits(map, DS1347_STATUS_REG, 97d9dcfa5fSAlexandre Belloni DS1347_NEOSC_BIT, DS1347_NEOSC_BIT); 98d9dcfa5fSAlexandre Belloni if (err) 99d9dcfa5fSAlexandre Belloni return err; 100617b26a0SRaghavendra Ganiga 101ee85bb5bSRaghavendra Ganiga buf[0] = bin2bcd(dt->tm_sec); 102ee85bb5bSRaghavendra Ganiga buf[1] = bin2bcd(dt->tm_min); 103ee85bb5bSRaghavendra Ganiga buf[2] = (bin2bcd(dt->tm_hour) & 0x3F); 104ee85bb5bSRaghavendra Ganiga buf[3] = bin2bcd(dt->tm_mday); 105ee85bb5bSRaghavendra Ganiga buf[4] = bin2bcd(dt->tm_mon + 1); 106ee85bb5bSRaghavendra Ganiga buf[5] = bin2bcd(dt->tm_wday + 1); 107147dae76SAlexandre Belloni buf[6] = bin2bcd(dt->tm_year % 100); 108ee85bb5bSRaghavendra Ganiga buf[7] = bin2bcd(0x00); 109617b26a0SRaghavendra Ganiga 110d9dcfa5fSAlexandre Belloni err = regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8); 111d9dcfa5fSAlexandre Belloni if (err) 112d9dcfa5fSAlexandre Belloni return err; 113d9dcfa5fSAlexandre Belloni 114147dae76SAlexandre Belloni century = (dt->tm_year / 100) + 19; 115147dae76SAlexandre Belloni err = regmap_write(map, DS1347_CENTURY_REG, century); 116147dae76SAlexandre Belloni if (err) 117147dae76SAlexandre Belloni return err; 118147dae76SAlexandre Belloni 119d9dcfa5fSAlexandre Belloni return regmap_update_bits(map, DS1347_STATUS_REG, 120d9dcfa5fSAlexandre Belloni DS1347_NEOSC_BIT | DS1347_OSF_BIT, 0); 121617b26a0SRaghavendra Ganiga } 122617b26a0SRaghavendra Ganiga 123617b26a0SRaghavendra Ganiga static const struct rtc_class_ops ds1347_rtc_ops = { 124617b26a0SRaghavendra Ganiga .read_time = ds1347_read_time, 125617b26a0SRaghavendra Ganiga .set_time = ds1347_set_time, 126617b26a0SRaghavendra Ganiga }; 127617b26a0SRaghavendra Ganiga 128617b26a0SRaghavendra Ganiga static int ds1347_probe(struct spi_device *spi) 129617b26a0SRaghavendra Ganiga { 130617b26a0SRaghavendra Ganiga struct rtc_device *rtc; 131ee85bb5bSRaghavendra Ganiga struct regmap_config config; 132ee85bb5bSRaghavendra Ganiga struct regmap *map; 133860c45b5SAlexandre Belloni int err; 134617b26a0SRaghavendra Ganiga 135ee85bb5bSRaghavendra Ganiga memset(&config, 0, sizeof(config)); 136ee85bb5bSRaghavendra Ganiga config.reg_bits = 8; 137ee85bb5bSRaghavendra Ganiga config.val_bits = 8; 138ee85bb5bSRaghavendra Ganiga config.read_flag_mask = 0x80; 139ee85bb5bSRaghavendra Ganiga config.max_register = 0x3F; 140ee85bb5bSRaghavendra Ganiga config.wr_table = &ds1347_access_table; 141ee85bb5bSRaghavendra Ganiga 142617b26a0SRaghavendra Ganiga /* spi setup with ds1347 in mode 3 and bits per word as 8 */ 143617b26a0SRaghavendra Ganiga spi->mode = SPI_MODE_3; 144617b26a0SRaghavendra Ganiga spi->bits_per_word = 8; 145617b26a0SRaghavendra Ganiga spi_setup(spi); 146617b26a0SRaghavendra Ganiga 147ee85bb5bSRaghavendra Ganiga map = devm_regmap_init_spi(spi, &config); 148ee85bb5bSRaghavendra Ganiga 149ee85bb5bSRaghavendra Ganiga if (IS_ERR(map)) { 150ee85bb5bSRaghavendra Ganiga dev_err(&spi->dev, "ds1347 regmap init spi failed\n"); 151ee85bb5bSRaghavendra Ganiga return PTR_ERR(map); 152ee85bb5bSRaghavendra Ganiga } 153ee85bb5bSRaghavendra Ganiga 154ee85bb5bSRaghavendra Ganiga spi_set_drvdata(spi, map); 155ee85bb5bSRaghavendra Ganiga 156617b26a0SRaghavendra Ganiga /* Disable the write protect of rtc */ 157860c45b5SAlexandre Belloni err = regmap_update_bits(map, DS1347_CONTROL_REG, DS1347_WP_BIT, 0); 158860c45b5SAlexandre Belloni if (err) 159860c45b5SAlexandre Belloni return err; 160617b26a0SRaghavendra Ganiga 161554692d5SAlexandre Belloni rtc = devm_rtc_allocate_device(&spi->dev); 162617b26a0SRaghavendra Ganiga if (IS_ERR(rtc)) 163617b26a0SRaghavendra Ganiga return PTR_ERR(rtc); 164617b26a0SRaghavendra Ganiga 165554692d5SAlexandre Belloni rtc->ops = &ds1347_rtc_ops; 1663ce20a23SAlexandre Belloni rtc->range_min = RTC_TIMESTAMP_BEGIN_0000; 1673ce20a23SAlexandre Belloni rtc->range_max = RTC_TIMESTAMP_END_9999; 168554692d5SAlexandre Belloni 169554692d5SAlexandre Belloni return rtc_register_device(rtc); 170617b26a0SRaghavendra Ganiga } 171617b26a0SRaghavendra Ganiga 172617b26a0SRaghavendra Ganiga static struct spi_driver ds1347_driver = { 173617b26a0SRaghavendra Ganiga .driver = { 174617b26a0SRaghavendra Ganiga .name = "ds1347", 175617b26a0SRaghavendra Ganiga }, 176617b26a0SRaghavendra Ganiga .probe = ds1347_probe, 177617b26a0SRaghavendra Ganiga }; 178617b26a0SRaghavendra Ganiga 179617b26a0SRaghavendra Ganiga module_spi_driver(ds1347_driver); 180617b26a0SRaghavendra Ganiga 181617b26a0SRaghavendra Ganiga MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER"); 182617b26a0SRaghavendra Ganiga MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@gmail.com>"); 183617b26a0SRaghavendra Ganiga MODULE_LICENSE("GPL v2"); 184