diff options
Diffstat (limited to 'drivers/rtc/rtc-rx6110.c')
| -rw-r--r-- | drivers/rtc/rtc-rx6110.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rx6110.c b/drivers/rtc/rtc-rx6110.c new file mode 100644 index 000000000000..bbad00b233bc --- /dev/null +++ b/drivers/rtc/rtc-rx6110.c @@ -0,0 +1,402 @@ +/* + * 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. + * + * This driver software is distributed as is, without any warranty of any kind, + * either express or implied as further specified in the GNU Public License. + * This software may be used and distributed according to the terms of the GNU + * Public License, version 2 as published by the Free Software Foundation. + * See the file COPYING in the main directory of this archive for more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#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/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 %ds %dm %dh %dmd %dm %dy\n", __func__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year); + + /* + * 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 %ds %dm %dh %dmd %dm %dy\n", __func__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year); + + /* + * 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 %ds %dm %dh %dmd %dm %dy\n", __func__, + tm->tm_sec, tm->tm_min, tm->tm_hour, + tm->tm_mday, tm->tm_mon, tm->tm_year); + + return rtc_valid_tm(tm); +} + +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 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 int rx6110_remove(struct spi_device *spi) +{ + return 0; +} + +static const struct spi_device_id rx6110_id[] = { + { "rx6110", 0 }, + { } +}; +MODULE_DEVICE_TABLE(spi, rx6110_id); + +static struct spi_driver rx6110_driver = { + .driver = { + .name = RX6110_DRIVER_NAME, + .owner = THIS_MODULE, + }, + .probe = rx6110_probe, + .remove = rx6110_remove, + .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"); |