Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / rtc / rtc-m41t94.c

diff --git a/kernel/drivers/rtc/rtc-m41t94.c b/kernel/drivers/rtc/rtc-m41t94.c
new file mode 100644 (file)
index 0000000..8d800b1
--- /dev/null
+++ b/kernel/drivers/rtc/rtc-m41t94.c
@@ -0,0 +1,150 @@
+/*
+ * Driver for ST M41T94 SPI RTC
+ *
+ * Copyright (C) 2008 Kim B. Heino
+ *
+ * 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/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+
+#define M41T94_REG_SECONDS     0x01
+#define M41T94_REG_MINUTES     0x02
+#define M41T94_REG_HOURS       0x03
+#define M41T94_REG_WDAY                0x04
+#define M41T94_REG_DAY         0x05
+#define M41T94_REG_MONTH       0x06
+#define M41T94_REG_YEAR                0x07
+#define M41T94_REG_HT          0x0c
+
+#define M41T94_BIT_HALT                0x40
+#define M41T94_BIT_STOP                0x80
+#define M41T94_BIT_CB          0x40
+#define M41T94_BIT_CEB         0x80
+
+static int m41t94_set_time(struct device *dev, struct rtc_time *tm)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       u8 buf[8]; /* write cmd + 7 registers */
+
+       dev_dbg(dev, "%s secs=%d, mins=%d, "
+               "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
+               "write", tm->tm_sec, tm->tm_min,
+               tm->tm_hour, tm->tm_mday,
+               tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+       buf[0] = 0x80 | M41T94_REG_SECONDS; /* write time + date */
+       buf[M41T94_REG_SECONDS] = bin2bcd(tm->tm_sec);
+       buf[M41T94_REG_MINUTES] = bin2bcd(tm->tm_min);
+       buf[M41T94_REG_HOURS]   = bin2bcd(tm->tm_hour);
+       buf[M41T94_REG_WDAY]    = bin2bcd(tm->tm_wday + 1);
+       buf[M41T94_REG_DAY]     = bin2bcd(tm->tm_mday);
+       buf[M41T94_REG_MONTH]   = bin2bcd(tm->tm_mon + 1);
+
+       buf[M41T94_REG_HOURS] |= M41T94_BIT_CEB;
+       if (tm->tm_year >= 100)
+               buf[M41T94_REG_HOURS] |= M41T94_BIT_CB;
+       buf[M41T94_REG_YEAR] = bin2bcd(tm->tm_year % 100);
+
+       return spi_write(spi, buf, 8);
+}
+
+static int m41t94_read_time(struct device *dev, struct rtc_time *tm)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       u8 buf[2];
+       int ret, hour;
+
+       /* clear halt update bit */
+       ret = spi_w8r8(spi, M41T94_REG_HT);
+       if (ret < 0)
+               return ret;
+       if (ret & M41T94_BIT_HALT) {
+               buf[0] = 0x80 | M41T94_REG_HT;
+               buf[1] = ret & ~M41T94_BIT_HALT;
+               spi_write(spi, buf, 2);
+       }
+
+       /* clear stop bit */
+       ret = spi_w8r8(spi, M41T94_REG_SECONDS);
+       if (ret < 0)
+               return ret;
+       if (ret & M41T94_BIT_STOP) {
+               buf[0] = 0x80 | M41T94_REG_SECONDS;
+               buf[1] = ret & ~M41T94_BIT_STOP;
+               spi_write(spi, buf, 2);
+       }
+
+       tm->tm_sec  = bcd2bin(spi_w8r8(spi, M41T94_REG_SECONDS));
+       tm->tm_min  = bcd2bin(spi_w8r8(spi, M41T94_REG_MINUTES));
+       hour = spi_w8r8(spi, M41T94_REG_HOURS);
+       tm->tm_hour = bcd2bin(hour & 0x3f);
+       tm->tm_wday = bcd2bin(spi_w8r8(spi, M41T94_REG_WDAY)) - 1;
+       tm->tm_mday = bcd2bin(spi_w8r8(spi, M41T94_REG_DAY));
+       tm->tm_mon  = bcd2bin(spi_w8r8(spi, M41T94_REG_MONTH)) - 1;
+       tm->tm_year = bcd2bin(spi_w8r8(spi, M41T94_REG_YEAR));
+       if ((hour & M41T94_BIT_CB) || !(hour & M41T94_BIT_CEB))
+               tm->tm_year += 100;
+
+       dev_dbg(dev, "%s secs=%d, mins=%d, "
+               "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
+               "read", tm->tm_sec, tm->tm_min,
+               tm->tm_hour, tm->tm_mday,
+               tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+       /* initial clock setting can be undefined */
+       return rtc_valid_tm(tm);
+}
+
+static const struct rtc_class_ops m41t94_rtc_ops = {
+       .read_time      = m41t94_read_time,
+       .set_time       = m41t94_set_time,
+};
+
+static struct spi_driver m41t94_driver;
+
+static int m41t94_probe(struct spi_device *spi)
+{
+       struct rtc_device *rtc;
+       int res;
+
+       spi->bits_per_word = 8;
+       spi_setup(spi);
+
+       res = spi_w8r8(spi, M41T94_REG_SECONDS);
+       if (res < 0) {
+               dev_err(&spi->dev, "not found.\n");
+               return res;
+       }
+
+       rtc = devm_rtc_device_register(&spi->dev, m41t94_driver.driver.name,
+                                       &m41t94_rtc_ops, THIS_MODULE);
+       if (IS_ERR(rtc))
+               return PTR_ERR(rtc);
+
+       spi_set_drvdata(spi, rtc);
+
+       return 0;
+}
+
+static struct spi_driver m41t94_driver = {
+       .driver = {
+               .name   = "rtc-m41t94",
+               .owner  = THIS_MODULE,
+       },
+       .probe  = m41t94_probe,
+};
+
+module_spi_driver(m41t94_driver);
+
+MODULE_AUTHOR("Kim B. Heino <Kim.Heino@bluegiga.com>");
+MODULE_DESCRIPTION("Driver for ST M41T94 SPI RTC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:rtc-m41t94");