--- /dev/null
+/*
+ * Driver for Epson RTC-9701JE
+ *
+ * Copyright (C) 2008 Magnus Damm
+ *
+ * Based on rtc-max6902.c
+ *
+ * Copyright (C) 2006 8D Technologies inc.
+ * Copyright (C) 2004 Compulab Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+
+#define RSECCNT 0x00 /* Second Counter */
+#define RMINCNT 0x01 /* Minute Counter */
+#define RHRCNT 0x02 /* Hour Counter */
+#define RWKCNT 0x03 /* Week Counter */
+#define RDAYCNT 0x04 /* Day Counter */
+#define RMONCNT 0x05 /* Month Counter */
+#define RYRCNT 0x06 /* Year Counter */
+#define R100CNT 0x07 /* Y100 Counter */
+#define RMINAR 0x08 /* Minute Alarm */
+#define RHRAR 0x09 /* Hour Alarm */
+#define RWKAR 0x0a /* Week/Day Alarm */
+#define RTIMCNT 0x0c /* Interval Timer */
+#define REXT 0x0d /* Extension Register */
+#define RFLAG 0x0e /* RTC Flag Register */
+#define RCR 0x0f /* RTC Control Register */
+
+static int write_reg(struct device *dev, int address, unsigned char data)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ unsigned char buf[2];
+
+ buf[0] = address & 0x7f;
+ buf[1] = data;
+
+ return spi_write(spi, buf, ARRAY_SIZE(buf));
+}
+
+static int read_regs(struct device *dev, unsigned char *regs, int no_regs)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ u8 txbuf[1], rxbuf[1];
+ int k, ret;
+
+ ret = 0;
+
+ for (k = 0; ret == 0 && k < no_regs; k++) {
+ txbuf[0] = 0x80 | regs[k];
+ ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
+ regs[k] = rxbuf[0];
+ }
+
+ return ret;
+}
+
+static int r9701_get_datetime(struct device *dev, struct rtc_time *dt)
+{
+ int ret;
+ unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,
+ RDAYCNT, RMONCNT, RYRCNT };
+
+ ret = read_regs(dev, buf, ARRAY_SIZE(buf));
+ if (ret)
+ return ret;
+
+ memset(dt, 0, sizeof(*dt));
+
+ dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */
+ dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */
+ dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */
+
+ dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */
+ dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */
+ dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */
+
+ /* the rtc device may contain illegal values on power up
+ * according to the data sheet. make sure they are valid.
+ */
+
+ return rtc_valid_tm(dt);
+}
+
+static int r9701_set_datetime(struct device *dev, struct rtc_time *dt)
+{
+ int ret, year;
+
+ year = dt->tm_year + 1900;
+ if (year >= 2100 || year < 2000)
+ return -EINVAL;
+
+ ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));
+ ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));
+ ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));
+ ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));
+ ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
+ ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));
+ ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday);
+
+ return ret;
+}
+
+static const struct rtc_class_ops r9701_rtc_ops = {
+ .read_time = r9701_get_datetime,
+ .set_time = r9701_set_datetime,
+};
+
+static int r9701_probe(struct spi_device *spi)
+{
+ struct rtc_device *rtc;
+ struct rtc_time dt;
+ unsigned char tmp;
+ int res;
+
+ tmp = R100CNT;
+ res = read_regs(&spi->dev, &tmp, 1);
+ if (res || tmp != 0x20) {
+ dev_err(&spi->dev, "cannot read RTC register\n");
+ return -ENODEV;
+ }
+
+ /*
+ * The device seems to be present. Now check if the registers
+ * contain invalid values. If so, try to write a default date:
+ * 2000/1/1 00:00:00
+ */
+ if (r9701_get_datetime(&spi->dev, &dt)) {
+ dev_info(&spi->dev, "trying to repair invalid date/time\n");
+ dt.tm_sec = 0;
+ dt.tm_min = 0;
+ dt.tm_hour = 0;
+ dt.tm_mday = 1;
+ dt.tm_mon = 0;
+ dt.tm_year = 100;
+
+ if (r9701_set_datetime(&spi->dev, &dt) ||
+ r9701_get_datetime(&spi->dev, &dt)) {
+ dev_err(&spi->dev, "cannot repair RTC register\n");
+ return -ENODEV;
+ }
+ }
+
+ rtc = devm_rtc_device_register(&spi->dev, "r9701",
+ &r9701_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ spi_set_drvdata(spi, rtc);
+
+ return 0;
+}
+
+static int r9701_remove(struct spi_device *spi)
+{
+ return 0;
+}
+
+static struct spi_driver r9701_driver = {
+ .driver = {
+ .name = "rtc-r9701",
+ .owner = THIS_MODULE,
+ },
+ .probe = r9701_probe,
+ .remove = r9701_remove,
+};
+
+module_spi_driver(r9701_driver);
+
+MODULE_DESCRIPTION("r9701 spi RTC driver");
+MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:rtc-r9701");
Code Review / kvmfornfv.git / blobdiff