--- /dev/null
+/*
+ * A SPI driver for the Ricoh RS5C348 RTC
+ *
+ * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ *
+ * 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.
+ *
+ * The board specific init code should provide characteristics of this
+ * device:
+ * Mode 1 (High-Active, Shift-Then-Sample), High Avtive CS
+ */
+
+#include <linux/bcd.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/rtc.h>
+#include <linux/workqueue.h>
+#include <linux/spi/spi.h>
+
+#define DRV_VERSION "0.1"
+
+#define RS5C348_REG_SECS 0
+#define RS5C348_REG_MINS 1
+#define RS5C348_REG_HOURS 2
+#define RS5C348_REG_WDAY 3
+#define RS5C348_REG_DAY 4
+#define RS5C348_REG_MONTH 5
+#define RS5C348_REG_YEAR 6
+#define RS5C348_REG_CTL1 14
+#define RS5C348_REG_CTL2 15
+
+#define RS5C348_SECS_MASK 0x7f
+#define RS5C348_MINS_MASK 0x7f
+#define RS5C348_HOURS_MASK 0x3f
+#define RS5C348_WDAY_MASK 0x03
+#define RS5C348_DAY_MASK 0x3f
+#define RS5C348_MONTH_MASK 0x1f
+
+#define RS5C348_BIT_PM 0x20 /* REG_HOURS */
+#define RS5C348_BIT_Y2K 0x80 /* REG_MONTH */
+#define RS5C348_BIT_24H 0x20 /* REG_CTL1 */
+#define RS5C348_BIT_XSTP 0x10 /* REG_CTL2 */
+#define RS5C348_BIT_VDET 0x40 /* REG_CTL2 */
+
+#define RS5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */
+#define RS5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */
+#define RS5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */
+#define RS5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */
+
+struct rs5c348_plat_data {
+ struct rtc_device *rtc;
+ int rtc_24h;
+};
+
+static int
+rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ struct rs5c348_plat_data *pdata = spi->dev.platform_data;
+ u8 txbuf[5+7], *txp;
+ int ret;
+
+ /* Transfer 5 bytes before writing SEC. This gives 31us for carry. */
+ txp = txbuf;
+ txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
+ txbuf[1] = 0; /* dummy */
+ txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
+ txbuf[3] = 0; /* dummy */
+ txbuf[4] = RS5C348_CMD_MW(RS5C348_REG_SECS); /* cmd, sec, ... */
+ txp = &txbuf[5];
+ txp[RS5C348_REG_SECS] = BIN2BCD(tm->tm_sec);
+ txp[RS5C348_REG_MINS] = BIN2BCD(tm->tm_min);
+ if (pdata->rtc_24h) {
+ txp[RS5C348_REG_HOURS] = BIN2BCD(tm->tm_hour);
+ } else {
+ /* hour 0 is AM12, noon is PM12 */
+ txp[RS5C348_REG_HOURS] = BIN2BCD((tm->tm_hour + 11) % 12 + 1) |
+ (tm->tm_hour >= 12 ? RS5C348_BIT_PM : 0);
+ }
+ txp[RS5C348_REG_WDAY] = BIN2BCD(tm->tm_wday);
+ txp[RS5C348_REG_DAY] = BIN2BCD(tm->tm_mday);
+ txp[RS5C348_REG_MONTH] = BIN2BCD(tm->tm_mon + 1) |
+ (tm->tm_year >= 100 ? RS5C348_BIT_Y2K : 0);
+ txp[RS5C348_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
+ /* write in one transfer to avoid data inconsistency */
+ ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), NULL, 0);
+ udelay(62); /* Tcsr 62us */
+ return ret;
+}
+
+static int
+rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ struct rs5c348_plat_data *pdata = spi->dev.platform_data;
+ u8 txbuf[5], rxbuf[7];
+ int ret;
+
+ /* Transfer 5 byte befores reading SEC. This gives 31us for carry. */
+ txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
+ txbuf[1] = 0; /* dummy */
+ txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
+ txbuf[3] = 0; /* dummy */
+ txbuf[4] = RS5C348_CMD_MR(RS5C348_REG_SECS); /* cmd, sec, ... */
+
+ /* read in one transfer to avoid data inconsistency */
+ ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
+ rxbuf, sizeof(rxbuf));
+ udelay(62); /* Tcsr 62us */
+ if (ret < 0)
+ return ret;
+
+ tm->tm_sec = BCD2BIN(rxbuf[RS5C348_REG_SECS] & RS5C348_SECS_MASK);
+ tm->tm_min = BCD2BIN(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK);
+ tm->tm_hour = BCD2BIN(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK);
+ if (!pdata->rtc_24h) {
+ tm->tm_hour %= 12;
+ if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM)
+ tm->tm_hour += 12;
+ }
+ tm->tm_wday = BCD2BIN(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK);
+ tm->tm_mday = BCD2BIN(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK);
+ tm->tm_mon =
+ BCD2BIN(rxbuf[RS5C348_REG_MONTH] & RS5C348_MONTH_MASK) - 1;
+ /* year is 1900 + tm->tm_year */
+ tm->tm_year = BCD2BIN(rxbuf[RS5C348_REG_YEAR]) +
+ ((rxbuf[RS5C348_REG_MONTH] & RS5C348_BIT_Y2K) ? 100 : 0);
+
+ if (rtc_valid_tm(tm) < 0) {
+ dev_err(&spi->dev, "retrieved date/time is not valid.\n");
+ rtc_time_to_tm(0, tm);
+ }
+
+ return 0;
+}
+
+static struct rtc_class_ops rs5c348_rtc_ops = {
+ .read_time = rs5c348_rtc_read_time,
+ .set_time = rs5c348_rtc_set_time,
+};
+
+static struct spi_driver rs5c348_driver;
+
+static int __devinit rs5c348_probe(struct spi_device *spi)
+{
+ int ret;
+ struct rtc_device *rtc;
+ struct rs5c348_plat_data *pdata;
+
+ pdata = kzalloc(sizeof(struct rs5c348_plat_data), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+ spi->dev.platform_data = pdata;
+
+ /* Check D7 of SECOND register */
+ ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_SECS));
+ if (ret < 0 || (ret & 0x80)) {
+ dev_err(&spi->dev, "not found.\n");
+ goto kfree_exit;
+ }
+
+ dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
+ dev_info(&spi->dev, "spiclk %u KHz.\n",
+ (spi->max_speed_hz + 500) / 1000);
+
+ /* turn RTC on if it was not on */
+ ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));
+ if (ret < 0)
+ goto kfree_exit;
+ if (ret & (RS5C348_BIT_XSTP | RS5C348_BIT_VDET)) {
+ u8 buf[2];
+ if (ret & RS5C348_BIT_VDET)
+ dev_warn(&spi->dev, "voltage-low detected.\n");
+ buf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2);
+ buf[1] = 0;
+ ret = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0);
+ if (ret < 0)
+ goto kfree_exit;
+ }
+
+ ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1));
+ if (ret < 0)
+ goto kfree_exit;
+ if (ret & RS5C348_BIT_24H)
+ pdata->rtc_24h = 1;
+
+ rtc = rtc_device_register(rs5c348_driver.driver.name, &spi->dev,
+ &rs5c348_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc)) {
+ ret = PTR_ERR(rtc);
+ goto kfree_exit;
+ }
+
+ pdata->rtc = rtc;
+
+ return 0;
+ kfree_exit:
+ kfree(pdata);
+ return ret;
+}
+
+static int __devexit rs5c348_remove(struct spi_device *spi)
+{
+ struct rs5c348_plat_data *pdata = spi->dev.platform_data;
+ struct rtc_device *rtc = pdata->rtc;
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+ kfree(pdata);
+ return 0;
+}
+
+static struct spi_driver rs5c348_driver = {
+ .driver = {
+ .name = "rs5c348",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = rs5c348_probe,
+ .remove = __devexit_p(rs5c348_remove),
+};
+
+static __init int rs5c348_init(void)
+{
+ return spi_register_driver(&rs5c348_driver);
+}
+
+static __exit void rs5c348_exit(void)
+{
+ spi_unregister_driver(&rs5c348_driver);
+}
+
+module_init(rs5c348_init);
+module_exit(rs5c348_exit);
+
+MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
+MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
projects / platform / kernel / linux-exynos.git / commitdiff