Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / rtc / rtc-max6902.c

diff --git a/kernel/drivers/rtc/rtc-max6902.c b/kernel/drivers/rtc/rtc-max6902.c
new file mode 100644 (file)
index 0000000..ac3f419
--- /dev/null
+++ b/kernel/drivers/rtc/rtc-max6902.c
@@ -0,0 +1,159 @@
+/* drivers/rtc/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.
+ *
+ * Driver for MAX6902 spi RTC
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/spi/spi.h>
+#include <linux/bcd.h>
+
+#define MAX6902_REG_SECONDS            0x01
+#define MAX6902_REG_MINUTES            0x03
+#define MAX6902_REG_HOURS              0x05
+#define MAX6902_REG_DATE               0x07
+#define MAX6902_REG_MONTH              0x09
+#define MAX6902_REG_DAY                        0x0B
+#define MAX6902_REG_YEAR               0x0D
+#define MAX6902_REG_CONTROL            0x0F
+#define MAX6902_REG_CENTURY            0x13
+
+static int max6902_set_reg(struct device *dev, unsigned char address,
+                               unsigned char data)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       unsigned char buf[2];
+
+       /* MSB must be '0' to write */
+       buf[0] = address & 0x7f;
+       buf[1] = data;
+
+       return spi_write_then_read(spi, buf, 2, NULL, 0);
+}
+
+static int max6902_get_reg(struct device *dev, unsigned char address,
+                               unsigned char *data)
+{
+       struct spi_device *spi = to_spi_device(dev);
+
+       /* Set MSB to indicate read */
+       *data = address | 0x80;
+
+       return spi_write_then_read(spi, data, 1, data, 1);
+}
+
+static int max6902_read_time(struct device *dev, struct rtc_time *dt)
+{
+       int err, century;
+       struct spi_device *spi = to_spi_device(dev);
+       unsigned char buf[8];
+
+       buf[0] = 0xbf;  /* Burst read */
+
+       err = spi_write_then_read(spi, buf, 1, buf, 8);
+       if (err != 0)
+               return err;
+
+       /* The chip sends data in this order:
+        * Seconds, Minutes, Hours, Date, Month, Day, Year */
+       dt->tm_sec      = bcd2bin(buf[0]);
+       dt->tm_min      = bcd2bin(buf[1]);
+       dt->tm_hour     = bcd2bin(buf[2]);
+       dt->tm_mday     = bcd2bin(buf[3]);
+       dt->tm_mon      = bcd2bin(buf[4]) - 1;
+       dt->tm_wday     = bcd2bin(buf[5]);
+       dt->tm_year     = bcd2bin(buf[6]);
+
+       /* Read century */
+       err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &buf[0]);
+       if (err != 0)
+               return err;
+
+       century = bcd2bin(buf[0]) * 100;
+
+       dt->tm_year += century;
+       dt->tm_year -= 1900;
+
+       return rtc_valid_tm(dt);
+}
+
+static int max6902_set_time(struct device *dev, struct rtc_time *dt)
+{
+       dt->tm_year = dt->tm_year + 1900;
+
+       /* Remove write protection */
+       max6902_set_reg(dev, MAX6902_REG_CONTROL, 0);
+
+       max6902_set_reg(dev, MAX6902_REG_SECONDS, bin2bcd(dt->tm_sec));
+       max6902_set_reg(dev, MAX6902_REG_MINUTES, bin2bcd(dt->tm_min));
+       max6902_set_reg(dev, MAX6902_REG_HOURS, bin2bcd(dt->tm_hour));
+
+       max6902_set_reg(dev, MAX6902_REG_DATE, bin2bcd(dt->tm_mday));
+       max6902_set_reg(dev, MAX6902_REG_MONTH, bin2bcd(dt->tm_mon + 1));
+       max6902_set_reg(dev, MAX6902_REG_DAY, bin2bcd(dt->tm_wday));
+       max6902_set_reg(dev, MAX6902_REG_YEAR, bin2bcd(dt->tm_year % 100));
+       max6902_set_reg(dev, MAX6902_REG_CENTURY, bin2bcd(dt->tm_year / 100));
+
+       /* Compulab used a delay here. However, the datasheet
+        * does not mention a delay being required anywhere... */
+       /* delay(2000); */
+
+       /* Write protect */
+       max6902_set_reg(dev, MAX6902_REG_CONTROL, 0x80);
+
+       return 0;
+}
+
+static const struct rtc_class_ops max6902_rtc_ops = {
+       .read_time      = max6902_read_time,
+       .set_time       = max6902_set_time,
+};
+
+static int max6902_probe(struct spi_device *spi)
+{
+       struct rtc_device *rtc;
+       unsigned char tmp;
+       int res;
+
+       spi->mode = SPI_MODE_3;
+       spi->bits_per_word = 8;
+       spi_setup(spi);
+
+       res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp);
+       if (res != 0)
+               return res;
+
+       rtc = devm_rtc_device_register(&spi->dev, "max6902",
+                               &max6902_rtc_ops, THIS_MODULE);
+       if (IS_ERR(rtc))
+               return PTR_ERR(rtc);
+
+       spi_set_drvdata(spi, rtc);
+       return 0;
+}
+
+static struct spi_driver max6902_driver = {
+       .driver = {
+               .name   = "rtc-max6902",
+               .owner  = THIS_MODULE,
+       },
+       .probe  = max6902_probe,
+};
+
+module_spi_driver(max6902_driver);
+
+MODULE_DESCRIPTION("max6902 spi RTC driver");
+MODULE_AUTHOR("Raphael Assenat");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:rtc-max6902");