[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>
diff --git a/drivers/rtc/rtc-v3020.c b/drivers/rtc/rtc-v3020.c
new file mode 100644
index 0000000..a40f400
--- /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");