--- /dev/null
+/*
+ * 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");
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