+/*
+ * Au1xxx counter0 (aka Time-Of-Year counter) RTC interface driver.
+ *
+ * Copyright (C) 2008 Manuel Lauss <mano@roarinelk.homelinux.net>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+/* All current Au1xxx SoCs have 2 counters fed by an external 32.768 kHz
+ * crystal. Counter 0, which keeps counting during sleep/powerdown, is
+ * used to count seconds since the beginning of the unix epoch.
+ *
+ * The counters must be configured and enabled by bootloader/board code;
+ * no checks as to whether they really get a proper 32.768kHz clock are
+ * made as this would take far too long.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <asm/mach-au1x00/au1000.h>
+
+/* 32kHz clock enabled and detected */
+#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)
+
+static int au1xtoy_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned long t;
+
+ t = au_readl(SYS_TOYREAD);
+
+ rtc_time_to_tm(t, tm);
+
+ return rtc_valid_tm(tm);
+}
+
+static int au1xtoy_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned long t;
+
+ rtc_tm_to_time(tm, &t);
+
+ au_writel(t, SYS_TOYWRITE);
+ au_sync();
+
+ /* wait for the pending register write to succeed. This can
+ * take up to 6 seconds...
+ */
+ while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S)
+ msleep(1);
+
+ return 0;
+}
+
+static struct rtc_class_ops au1xtoy_rtc_ops = {
+ .read_time = au1xtoy_rtc_read_time,
+ .set_time = au1xtoy_rtc_set_time,
+};
+
+static int __devinit au1xtoy_rtc_probe(struct platform_device *pdev)
+{
+ struct rtc_device *rtcdev;
+ unsigned long t;
+ int ret;
+
+ t = au_readl(SYS_COUNTER_CNTRL);
+ if (!(t & CNTR_OK)) {
+ dev_err(&pdev->dev, "counters not working; aborting.\n");
+ ret = -ENODEV;
+ goto out_err;
+ }
+
+ ret = -ETIMEDOUT;
+
+ /* set counter0 tickrate to 1Hz if necessary */
+ if (au_readl(SYS_TOYTRIM) != 32767) {
+ /* wait until hardware gives access to TRIM register */
+ t = 0x00100000;
+ while ((au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T0S) && t--)
+ msleep(1);
+
+ if (!t) {
+ /* timed out waiting for register access; assume
+ * counters are unusable.
+ */
+ dev_err(&pdev->dev, "timeout waiting for access\n");
+ goto out_err;
+ }
+
+ /* set 1Hz TOY tick rate */
+ au_writel(32767, SYS_TOYTRIM);
+ au_sync();
+ }
+
+ /* wait until the hardware allows writes to the counter reg */
+ while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S)
+ msleep(1);
+
+ rtcdev = rtc_device_register("rtc-au1xxx", &pdev->dev,
+ &au1xtoy_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtcdev)) {
+ ret = PTR_ERR(rtcdev);
+ goto out_err;
+ }
+
+ platform_set_drvdata(pdev, rtcdev);
+
+ return 0;
+
+out_err:
+ return ret;
+}
+
+static int __devexit au1xtoy_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_device *rtcdev = platform_get_drvdata(pdev);
+
+ rtc_device_unregister(rtcdev);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver au1xrtc_driver = {
+ .driver = {
+ .name = "rtc-au1xxx",
+ .owner = THIS_MODULE,
+ },
+ .remove = __devexit_p(au1xtoy_rtc_remove),
+};
+
+static int __init au1xtoy_rtc_init(void)
+{
+ return platform_driver_probe(&au1xrtc_driver, au1xtoy_rtc_probe);
+}
+
+static void __exit au1xtoy_rtc_exit(void)
+{
+ platform_driver_unregister(&au1xrtc_driver);
+}
+
+module_init(au1xtoy_rtc_init);
+module_exit(au1xtoy_rtc_exit);
+
+MODULE_DESCRIPTION("Au1xxx TOY-counter-based RTC driver");
+MODULE_AUTHOR("Manuel Lauss <manuel.lauss@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-au1xxx");
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff