[PATCH] Add v3020 RTC support

This patch adds support for the v3020 RTC from EM Microelectronic.

The v3020 RTC is designed to be connected on a bus using only one data bit.
 Since any data bit may be used, it is necessary to specify this to the
driver by passing a struct v3020_platform_data pointer (see
include/linux/rtc-v3020.h) to the driver.

Part of the following code comes from the kernel patchs produced by
Compulab for their products.  The original file (available here:
http://raph.people.8d.com/misc/emv3020.c) was released under the terms of
the GPL license.

[akpm@osdl.org: cleanups]
Signed-off-by: Raphael Assenat <raph@raphnet.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 275 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 94746cfac7b5..8534012ebdef 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -227,4 +227,14 @@ config RTC_DRV_MAX6902
           This driver can also be built as a module. If so, the module
           will be called rtc-max6902.
 
+config RTC_DRV_V3020
+        tristate "EM Microelectronic V3020"
+        depends on RTC_CLASS
+        help
+          If you say yes here you will get support for the
+          EM Microelectronic v3020 RTC chip.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-v3020.
+
 endmenu
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index dd480d6bcdf8..cbb8e8a7f620 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_RTC_DRV_SA1100)	+= rtc-sa1100.o
 obj-$(CONFIG_RTC_DRV_VR41XX)    += rtc-vr41xx.o
 obj-$(CONFIG_RTC_DRV_PL031)     += rtc-pl031.o
 obj-$(CONFIG_RTC_DRV_MAX6902)   += rtc-max6902.o
+obj-$(CONFIG_RTC_DRV_V3020)     += rtc-v3020.o
diff --git a/drivers/rtc/rtc-v3020.c b/drivers/rtc/rtc-v3020.c
new file mode 100644
index 000000000000..a40f400acff6
--- /dev/null
+++ b/drivers/rtc/rtc-v3020.c
@@ -0,0 +1,264 @@
+/* drivers/rtc/rtc-v3020.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 the V3020 RTC
+ *
+ * Changelog:
+ *
+ *  10-May-2006: Raphael Assenat <raph@8d.com>
+ *                              - Converted to platform driver
+ *                              - Use the generic rtc class
+ *
+ *  ??-???-2004: Someone at Compulab
+ *                      - Initial driver creation.
+ *
+ */
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/types.h>
+#include <linux/bcd.h>
+#include <linux/rtc-v3020.h>
+
+#include <asm/io.h>
+
+#undef DEBUG
+
+struct v3020 {
+        void __iomem *ioaddress;
+        int leftshift;
+        struct rtc_device *rtc;
+};
+
+static void v3020_set_reg(struct v3020 *chip, unsigned char address,
+                        unsigned char data)
+{
+        int i;
+        unsigned char tmp;
+
+        tmp = address;
+        for (i = 0; i < 4; i++) {
+                writel((tmp & 1) << chip->leftshift, chip->ioaddress);
+                tmp >>= 1;
+        }
+
+        /* Commands dont have data */
+        if (!V3020_IS_COMMAND(address)) {
+                for (i = 0; i < 8; i++) {
+                        writel((data & 1) << chip->leftshift, chip->ioaddress);
+                        data >>= 1;
+                }
+        }
+}
+
+static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
+{
+        unsigned int data=0;
+        int i;
+
+        for (i = 0; i < 4; i++) {
+                writel((address & 1) << chip->leftshift, chip->ioaddress);
+                address >>= 1;
+        }
+
+        for (i = 0; i < 8; i++) {
+                data >>= 1;
+                if (readl(chip->ioaddress) & (1 << chip->leftshift))
+                        data |= 0x80;
+        }
+
+        return data;
+}
+
+static int v3020_read_time(struct device *dev, struct rtc_time *dt)
+{
+        struct v3020 *chip = dev_get_drvdata(dev);
+        int tmp;
+
+        /* Copy the current time to ram... */
+        v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
+
+        /* ...and then read constant values. */
+        tmp = v3020_get_reg(chip, V3020_SECONDS);
+        dt->tm_sec      = BCD2BIN(tmp);
+        tmp = v3020_get_reg(chip, V3020_MINUTES);
+        dt->tm_min      = BCD2BIN(tmp);
+        tmp = v3020_get_reg(chip, V3020_HOURS);
+        dt->tm_hour     = BCD2BIN(tmp);
+        tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
+        dt->tm_mday     = BCD2BIN(tmp);
+        tmp = v3020_get_reg(chip, V3020_MONTH);
+        dt->tm_mon      = BCD2BIN(tmp);
+        tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
+        dt->tm_wday     = BCD2BIN(tmp);
+        tmp = v3020_get_reg(chip, V3020_YEAR);
+        dt->tm_year = BCD2BIN(tmp)+100;
+
+#ifdef DEBUG
+        printk("\n%s : Read RTC values\n",__FUNCTION__);
+        printk("tm_hour: %i\n",dt->tm_hour);
+        printk("tm_min : %i\n",dt->tm_min);
+        printk("tm_sec : %i\n",dt->tm_sec);
+        printk("tm_year: %i\n",dt->tm_year);
+        printk("tm_mon : %i\n",dt->tm_mon);
+        printk("tm_mday: %i\n",dt->tm_mday);
+        printk("tm_wday: %i\n",dt->tm_wday);
+#endif
+
+        return 0;
+}
+
+
+static int v3020_set_time(struct device *dev, struct rtc_time *dt)
+{
+        struct v3020 *chip = dev_get_drvdata(dev);
+
+#ifdef DEBUG
+        printk("\n%s : Setting RTC values\n",__FUNCTION__);
+        printk("tm_sec : %i\n",dt->tm_sec);
+        printk("tm_min : %i\n",dt->tm_min);
+        printk("tm_hour: %i\n",dt->tm_hour);
+        printk("tm_mday: %i\n",dt->tm_mday);
+        printk("tm_wday: %i\n",dt->tm_wday);
+        printk("tm_year: %i\n",dt->tm_year);
+#endif
+
+        /* Write all the values to ram... */
+        v3020_set_reg(chip, V3020_SECONDS,      BIN2BCD(dt->tm_sec));
+        v3020_set_reg(chip, V3020_MINUTES,      BIN2BCD(dt->tm_min));
+        v3020_set_reg(chip, V3020_HOURS,        BIN2BCD(dt->tm_hour));
+        v3020_set_reg(chip, V3020_MONTH_DAY,    BIN2BCD(dt->tm_mday));
+        v3020_set_reg(chip, V3020_MONTH,        BIN2BCD(dt->tm_mon));
+        v3020_set_reg(chip, V3020_WEEK_DAY,     BIN2BCD(dt->tm_wday));
+        v3020_set_reg(chip, V3020_YEAR,         BIN2BCD(dt->tm_year % 100));
+
+        /* ...and set the clock. */
+        v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
+
+        /* Compulab used this delay here. I dont know why,
+         * the datasheet does not specify a delay. */
+        /*mdelay(5);*/
+
+        return 0;
+}
+
+static struct rtc_class_ops v3020_rtc_ops = {
+        .read_time      = v3020_read_time,
+        .set_time       = v3020_set_time,
+};
+
+static int rtc_probe(struct platform_device *pdev)
+{
+        struct v3020_platform_data *pdata = pdev->dev.platform_data;
+        struct v3020 *chip;
+        struct rtc_device *rtc;
+        int retval = -EBUSY;
+        int i;
+        int temp;
+
+        if (pdev->num_resources != 1)
+                return -EBUSY;
+
+        if (pdev->resource[0].flags != IORESOURCE_MEM)
+                return -EBUSY;
+
+        if (pdev == NULL)
+                return -EBUSY;
+
+        chip = kzalloc(sizeof *chip, GFP_KERNEL);
+        if (!chip)
+                return -ENOMEM;
+
+        chip->leftshift = pdata->leftshift;
+        chip->ioaddress = ioremap(pdev->resource[0].start, 1);
+        if (chip->ioaddress == NULL)
+                goto err_chip;
+
+        /* Make sure the v3020 expects a communication cycle
+         * by reading 8 times */
+        for (i = 0; i < 8; i++)
+                temp = readl(chip->ioaddress);
+
+        /* Test chip by doing a write/read sequence
+         * to the chip ram */
+        v3020_set_reg(chip, V3020_SECONDS, 0x33);
+        if(v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
+                retval = -ENODEV;
+                goto err_io;
+        }
+
+        /* Make sure frequency measurment mode, test modes, and lock
+         * are all disabled */
+        v3020_set_reg(chip, V3020_STATUS_0, 0x0);
+
+        dev_info(&pdev->dev, "Chip available at physical address 0x%p,"
+                "data connected to D%d\n",
+                (void*)pdev->resource[0].start,
+                chip->leftshift);
+
+        platform_set_drvdata(pdev, chip);
+
+        rtc = rtc_device_register("v3020",
+                                &pdev->dev, &v3020_rtc_ops, THIS_MODULE);
+        if (IS_ERR(rtc)) {
+                retval = PTR_ERR(rtc);
+                goto err_io;
+        }
+        chip->rtc = rtc;
+
+        return 0;
+
+err_io:
+        iounmap(chip->ioaddress);
+err_chip:
+        kfree(chip);
+
+        return retval;
+}
+
+static int rtc_remove(struct platform_device *dev)
+{
+        struct v3020 *chip = platform_get_drvdata(dev);
+        struct rtc_device *rtc = chip->rtc;
+
+        if (rtc)
+                rtc_device_unregister(rtc);
+
+        iounmap(chip->ioaddress);
+        kfree(chip);
+
+        return 0;
+}
+
+static struct platform_driver rtc_device_driver = {
+        .probe  = rtc_probe,
+        .remove = rtc_remove,
+        .driver = {
+                .name   = "v3020",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static __init int v3020_init(void)
+{
+        return platform_driver_register(&rtc_device_driver);
+}
+
+static __exit void v3020_exit(void)
+{
+        platform_driver_unregister(&rtc_device_driver);
+}
+
+module_init(v3020_init);
+module_exit(v3020_exit);
+
+MODULE_DESCRIPTION("V3020 RTC");
+MODULE_AUTHOR("Raphael Assenat");
+MODULE_LICENSE("GPL");