// SPDX-License-Identifier: GPL-2.0-only /* * Driver for the Epson RTC module RX-6110 SA * * Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de> * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved. */ #include <linux/bcd.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of_gpio.h> #include <linux/regmap.h> #include <linux/rtc.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/spi/spi.h> /* RX-6110 Register definitions */ #define RX6110_REG_SEC 0x10 #define RX6110_REG_MIN 0x11 #define RX6110_REG_HOUR 0x12 #define RX6110_REG_WDAY 0x13 #define RX6110_REG_MDAY 0x14 #define RX6110_REG_MONTH 0x15 #define RX6110_REG_YEAR 0x16 #define RX6110_REG_RES1 0x17 #define RX6110_REG_ALMIN 0x18 #define RX6110_REG_ALHOUR 0x19 #define RX6110_REG_ALWDAY 0x1A #define RX6110_REG_TCOUNT0 0x1B #define RX6110_REG_TCOUNT1 0x1C #define RX6110_REG_EXT 0x1D #define RX6110_REG_FLAG 0x1E #define RX6110_REG_CTRL 0x1F #define RX6110_REG_USER0 0x20 #define RX6110_REG_USER1 0x21 #define RX6110_REG_USER2 0x22 #define RX6110_REG_USER3 0x23 #define RX6110_REG_USER4 0x24 #define RX6110_REG_USER5 0x25 #define RX6110_REG_USER6 0x26 #define RX6110_REG_USER7 0x27 #define RX6110_REG_USER8 0x28 #define RX6110_REG_USER9 0x29 #define RX6110_REG_USERA 0x2A #define RX6110_REG_USERB 0x2B #define RX6110_REG_USERC 0x2C #define RX6110_REG_USERD 0x2D #define RX6110_REG_USERE 0x2E #define RX6110_REG_USERF 0x2F #define RX6110_REG_RES2 0x30 #define RX6110_REG_RES3 0x31 #define RX6110_REG_IRQ 0x32 #define RX6110_BIT_ALARM_EN BIT(7) /* Extension Register (1Dh) bit positions */ #define RX6110_BIT_EXT_TSEL0 BIT(0) #define RX6110_BIT_EXT_TSEL1 BIT(1) #define RX6110_BIT_EXT_TSEL2 BIT(2) #define RX6110_BIT_EXT_WADA BIT(3) #define RX6110_BIT_EXT_TE BIT(4) #define RX6110_BIT_EXT_USEL BIT(5) #define RX6110_BIT_EXT_FSEL0 BIT(6) #define RX6110_BIT_EXT_FSEL1 BIT(7) /* Flag Register (1Eh) bit positions */ #define RX6110_BIT_FLAG_VLF BIT(1) #define RX6110_BIT_FLAG_AF BIT(3) #define RX6110_BIT_FLAG_TF BIT(4) #define RX6110_BIT_FLAG_UF BIT(5) /* Control Register (1Fh) bit positions */ #define RX6110_BIT_CTRL_TBKE BIT(0) #define RX6110_BIT_CTRL_TBKON BIT(1) #define RX6110_BIT_CTRL_TSTP BIT(2) #define RX6110_BIT_CTRL_AIE BIT(3) #define RX6110_BIT_CTRL_TIE BIT(4) #define RX6110_BIT_CTRL_UIE BIT(5) #define RX6110_BIT_CTRL_STOP BIT(6) #define RX6110_BIT_CTRL_TEST BIT(7) enum { RTC_SEC = 0, RTC_MIN, RTC_HOUR, RTC_WDAY, RTC_MDAY, RTC_MONTH, RTC_YEAR, RTC_NR_TIME }; #define RX6110_DRIVER_NAME "rx6110" struct rx6110_data { struct rtc_device *rtc; struct regmap *regmap; }; /** * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding * * @tm: holds date and time * @data: holds the encoding in rx6110 native form */ static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data) { pr_debug("%s: date %ptRr\n", __func__, tm); /* * The year in the RTC is a value between 0 and 99. * Assume that this represents the current century * and disregard all other values. */ if (tm->tm_year < 100 || tm->tm_year >= 200) return -EINVAL; data[RTC_SEC] = bin2bcd(tm->tm_sec); data[RTC_MIN] = bin2bcd(tm->tm_min); data[RTC_HOUR] = bin2bcd(tm->tm_hour); data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday)); data[RTC_MDAY] = bin2bcd(tm->tm_mday); data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1); data[RTC_YEAR] = bin2bcd(tm->tm_year % 100); return 0; } /** * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time * * @data: holds the encoding in rx6110 native form * @tm: holds date and time */ static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm) { tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f); tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f); /* only 24-hour clock */ tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f); tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f); tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f); tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1; tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100; pr_debug("%s: date %ptRr\n", __func__, tm); /* * The year in the RTC is a value between 0 and 99. * Assume that this represents the current century * and disregard all other values. */ if (tm->tm_year < 100 || tm->tm_year >= 200) return -EINVAL; return 0; } /** * rx6110_set_time - set the current time in the rx6110 registers * * @dev: the rtc device in use * @tm: holds date and time * * BUG: The HW assumes every year that is a multiple of 4 to be a leap * year. Next time this is wrong is 2100, which will not be a leap year * * Note: If STOP is not set/cleared, the clock will start when the seconds * register is written * */ static int rx6110_set_time(struct device *dev, struct rtc_time *tm) { struct rx6110_data *rx6110 = dev_get_drvdata(dev); u8 data[RTC_NR_TIME]; int ret; ret = rx6110_rtc_tm_to_data(tm, data); if (ret < 0) return ret; /* set STOP bit before changing clock/calendar */ ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP); if (ret) return ret; ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data, RTC_NR_TIME); if (ret) return ret; /* The time in the RTC is valid. Be sure to have VLF cleared. */ ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, RX6110_BIT_FLAG_VLF, 0); if (ret) return ret; /* clear STOP bit after changing clock/calendar */ ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, RX6110_BIT_CTRL_STOP, 0); return ret; } /** * rx6110_get_time - get the current time from the rx6110 registers * @dev: the rtc device in use * @tm: holds date and time */ static int rx6110_get_time(struct device *dev, struct rtc_time *tm) { struct rx6110_data *rx6110 = dev_get_drvdata(dev); u8 data[RTC_NR_TIME]; int flags; int ret; ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); if (ret) return -EINVAL; /* check for VLF Flag (set at power-on) */ if ((flags & RX6110_BIT_FLAG_VLF)) { dev_warn(dev, "Voltage low, data is invalid.\n"); return -EINVAL; } /* read registers to date */ ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data, RTC_NR_TIME); if (ret) return ret; ret = rx6110_data_to_rtc_tm(data, tm); if (ret) return ret; dev_dbg(dev, "%s: date %ptRr\n", __func__, tm); return 0; } static const struct reg_sequence rx6110_default_regs[] = { { RX6110_REG_RES1, 0xB8 }, { RX6110_REG_RES2, 0x00 }, { RX6110_REG_RES3, 0x10 }, { RX6110_REG_IRQ, 0x00 }, { RX6110_REG_ALMIN, 0x00 }, { RX6110_REG_ALHOUR, 0x00 }, { RX6110_REG_ALWDAY, 0x00 }, }; /** * rx6110_init - initialize the rx6110 registers * * @rx6110: pointer to the rx6110 struct in use * */ static int rx6110_init(struct rx6110_data *rx6110) { struct rtc_device *rtc = rx6110->rtc; int flags; int ret; ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT, RX6110_BIT_EXT_TE, 0); if (ret) return ret; ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs, ARRAY_SIZE(rx6110_default_regs)); if (ret) return ret; ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); if (ret) return ret; /* check for VLF Flag (set at power-on) */ if ((flags & RX6110_BIT_FLAG_VLF)) dev_warn(&rtc->dev, "Voltage low, data loss detected.\n"); /* check for Alarm Flag */ if (flags & RX6110_BIT_FLAG_AF) dev_warn(&rtc->dev, "An alarm may have been missed.\n"); /* check for Periodic Timer Flag */ if (flags & RX6110_BIT_FLAG_TF) dev_warn(&rtc->dev, "Periodic timer was detected\n"); /* check for Update Timer Flag */ if (flags & RX6110_BIT_FLAG_UF) dev_warn(&rtc->dev, "Update timer was detected\n"); /* clear all flags BUT VLF */ ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, RX6110_BIT_FLAG_AF | RX6110_BIT_FLAG_UF | RX6110_BIT_FLAG_TF, 0); return ret; } static const struct rtc_class_ops rx6110_rtc_ops = { .read_time = rx6110_get_time, .set_time = rx6110_set_time, }; static struct regmap_config regmap_spi_config = { .reg_bits = 8, .val_bits = 8, .max_register = RX6110_REG_IRQ, .read_flag_mask = 0x80, }; /** * rx6110_probe - initialize rtc driver * @spi: pointer to spi device */ static int rx6110_probe(struct spi_device *spi) { struct rx6110_data *rx6110; int err; if ((spi->bits_per_word && spi->bits_per_word != 8) || (spi->max_speed_hz > 2000000) || (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) { dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n", spi->bits_per_word, spi->max_speed_hz, spi->mode); dev_warn(&spi->dev, "driving device in an unsupported mode"); } rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL); if (!rx6110) return -ENOMEM; rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config); if (IS_ERR(rx6110->regmap)) { dev_err(&spi->dev, "regmap init failed for rtc rx6110\n"); return PTR_ERR(rx6110->regmap); } spi_set_drvdata(spi, rx6110); rx6110->rtc = devm_rtc_device_register(&spi->dev, RX6110_DRIVER_NAME, &rx6110_rtc_ops, THIS_MODULE); if (IS_ERR(rx6110->rtc)) return PTR_ERR(rx6110->rtc); err = rx6110_init(rx6110); if (err) return err; rx6110->rtc->max_user_freq = 1; return 0; } static const struct spi_device_id rx6110_id[] = { { "rx6110", 0 }, { } }; MODULE_DEVICE_TABLE(spi, rx6110_id); static const struct of_device_id rx6110_spi_of_match[] = { { .compatible = "epson,rx6110" }, { }, }; MODULE_DEVICE_TABLE(of, rx6110_spi_of_match); static struct spi_driver rx6110_driver = { .driver = { .name = RX6110_DRIVER_NAME, .of_match_table = of_match_ptr(rx6110_spi_of_match), }, .probe = rx6110_probe, .id_table = rx6110_id, }; module_spi_driver(rx6110_driver); MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>"); MODULE_DESCRIPTION("RX-6110 SA RTC driver"); MODULE_LICENSE("GPL");