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Subject[patch 2.6.19-rc6 4/6] ACPI exports RTC extensions through platform_data
Date
Define platform_data for the MC146818 based RTCs, currently just holding
extensions standardized by ACPI (but available on some ACPI-neutral clones).

Update ACPI to export that RTC extension information through platform_data
to the PNP or platform bus device node.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

Index: g26/include/linux/mc146818rtc.h
===================================================================
--- g26.orig/include/linux/mc146818rtc.h 2006-11-20 10:03:06.000000000 -0800
+++ g26/include/linux/mc146818rtc.h 2006-11-20 10:10:45.000000000 -0800
@@ -18,6 +18,18 @@
#ifdef __KERNEL__
#include <linux/spinlock.h> /* spinlock_t */
extern spinlock_t rtc_lock; /* serialize CMOS RAM access */
+
+/* Some RTCs extend the mc146818 register set to support alarms of more
+ * than 24 hours in the future; or dates that include a century code.
+ * And sometimes the RTC alarm can wake the system from suspend-to-disk.
+ * This platform_data structure can pass this information to the driver.
+ */
+struct cmos_rtc_board_info {
+ u8 rtc_day_alarm; /* zero, or register index */
+ u8 rtc_mon_alarm; /* zero, or register index */
+ u8 rtc_century; /* zero, or register index */
+ u8 wake_from_std; /* true iff alarm wakes from STD */
+};
#endif

/**********************************************************************
Index: g26/drivers/acpi/glue.c
===================================================================
--- g26.orig/drivers/acpi/glue.c 2006-11-20 10:03:06.000000000 -0800
+++ g26/drivers/acpi/glue.c 2006-11-20 10:10:45.000000000 -0800
@@ -358,3 +358,107 @@ static int __init init_acpi_device_notif
}

arch_initcall(init_acpi_device_notify);
+
+
+#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE)
+
+/* Every ACPI platform has a mc146818 compatible "cmos rtc". We want
+ * to find its device node, so we can pass ACPI-specific config data
+ * to its driver. So we'll just probe for that device -- with a dummy
+ * driver, using the relevant bus -- before the RTC driver initializes.
+ */
+#include <linux/mc146818rtc.h>
+
+static struct cmos_rtc_board_info rtc_info;
+
+static struct device *rtc_dev __initdata;
+static char drvname[] __initdata = "rtc_cmos";
+
+
+#ifdef CONFIG_PNPACPI
+
+/* PNP devices are registered in a subsys_initcall();
+ * ACPI specifies the PNP IDs to use.
+ */
+#include <linux/pnp.h>
+
+static struct pnp_device_id rtc_ids[] __initdata = {
+ { .id = "PNP0b00", },
+ { .id = "PNP0b01", },
+ { .id = "PNP0b02", },
+ { },
+};
+
+static int __init
+rtc_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
+{
+ rtc_dev = &pnp->dev;
+ return -ENXIO;
+}
+
+static struct pnp_driver cmos_pnp_driver __initdata = {
+ .name = drvname,
+ .id_table = rtc_ids,
+ .probe = rtc_pnp_probe,
+};
+
+static struct device *__init get_rtc_dev(void)
+{
+ if (pnp_register_driver(&cmos_pnp_driver) == 0)
+ pnp_unregister_driver(&cmos_pnp_driver);
+ return rtc_dev;
+}
+
+#else
+
+/* We expect platforms to register an RTC device, conventionally at or
+ * near arch_initcall(). That should work even without ACPI. The driver
+ * name matters; it must match the driver.
+ */
+#include <linux/platform_device.h>
+
+static int __init rtc_platform_probe(struct platform_device *pdev)
+{
+ rtc_dev = &pdev->dev;
+ return -ENXIO;
+}
+
+static struct platform_driver rtc_platform_driver __initdata = {
+ .driver = {
+ .name = drvname,
+ },
+ .probe = rtc_platform_probe,
+};
+
+static struct device *__init get_rtc_dev(void)
+{
+ if (platform_driver_register(&rtc_platform_driver) == 0)
+ platform_driver_unregister(&rtc_platform_driver);
+ return rtc_dev;
+}
+
+#endif
+
+static int __init acpi_rtc_init(void)
+{
+ struct device *dev = get_rtc_dev();
+
+ if (dev) {
+ rtc_info.rtc_day_alarm = acpi_gbl_FADT->day_alrm;
+ rtc_info.rtc_mon_alarm = acpi_gbl_FADT->mon_alrm;
+ rtc_info.rtc_century = acpi_gbl_FADT->century;
+
+ /* REVISIT iff revision > FADT2_REVISION_ID ? */
+ rtc_info.wake_from_std = acpi_gbl_FADT->rtcs4;
+
+ dev->platform_data = &rtc_info;
+
+ /* RTC always wakes from S1/S2/S3, and often S4/STD */
+ device_init_wakeup(dev, 1);
+ } else
+ pr_debug("ACPI: RTC unavailable?\n");
+ return 0;
+}
+fs_initcall(acpi_rtc_init);
+
+#endif
-
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