Enable RTC for Ebony and Walnut (v2)
David Gibson
dwg at au1.ibm.com
Fri Jan 11 14:25:34 EST 2008
This patch extends the Ebony and Walnut platform code to instantiate
the existing ds1742 RTC class driver for the DS1743 RTC/NVRAM chip
found on both those boards. The patch uses a helper function to scan
the device tree and instantiate the appropriate platform_device based
on it, so it should be easy to extend for other boards which have mmio
mapped RTC chips.
Along with this, the device tree binding for the ds1743 chips is
tweaked, based on the existing DS1385 OF binding found at:
http://playground.sun.com/1275/proposals/Closed/Remanded/Accepted/346-it.txt
Although that document covers the NVRAM portion of the chip, whereas
here we're interested in the RTC portion, so it's not entirely clear
if that's a good model.
This implements only RTC class driver support - that is /dev/rtc0, not
/dev/rtc, and the low-level get/set time callbacks remain
unimplemented. That means in order to get at the clock you will
either need a modified version of hwclock which will look at
/dev/rtc0, or you'll need to configure udev to symlink rtc0 to rtc.
Signed-off-by: David Gibson <david at gibson.dropbear.id.au>
---
Updated for kernel changes and feedback.
Index: working-2.6/arch/powerpc/boot/dts/ebony.dts
===================================================================
--- working-2.6.orig/arch/powerpc/boot/dts/ebony.dts 2008-01-11 11:45:27.000000000 +1100
+++ working-2.6/arch/powerpc/boot/dts/ebony.dts 2008-01-11 14:17:03.000000000 +1100
@@ -158,9 +158,10 @@
};
};
- ds1743 at 1,0 {
+ nvram at 1,0 {
/* NVRAM & RTC */
- compatible = "ds1743";
+ compatible = "ds1743-nvram";
+ #bytes = <2000>;
reg = <1 0 2000>;
};
Index: working-2.6/arch/powerpc/platforms/44x/ebony.c
===================================================================
--- working-2.6.orig/arch/powerpc/platforms/44x/ebony.c 2008-01-11 11:45:27.000000000 +1100
+++ working-2.6/arch/powerpc/platforms/44x/ebony.c 2008-01-11 14:17:03.000000000 +1100
@@ -18,6 +18,7 @@
#include <linux/init.h>
#include <linux/of_platform.h>
+#include <linux/rtc.h>
#include <asm/machdep.h>
#include <asm/prom.h>
@@ -38,6 +39,7 @@ static __initdata struct of_device_id eb
static int __init ebony_device_probe(void)
{
of_platform_bus_probe(NULL, ebony_of_bus, NULL);
+ of_instantiate_rtc();
return 0;
}
Index: working-2.6/arch/powerpc/platforms/Kconfig
===================================================================
--- working-2.6.orig/arch/powerpc/platforms/Kconfig 2007-12-10 10:52:44.000000000 +1100
+++ working-2.6/arch/powerpc/platforms/Kconfig 2008-01-11 14:17:03.000000000 +1100
@@ -315,6 +315,12 @@ config FSL_ULI1575
config CPM
bool
+config OF_RTC
+ bool
+ help
+ Uses information from the OF or flattened device tree to instatiate
+ platform devices for direct mapped RTC chips like the DS1742 or DS1743.
+
source "arch/powerpc/sysdev/bestcomm/Kconfig"
endmenu
Index: working-2.6/arch/powerpc/sysdev/Makefile
===================================================================
--- working-2.6.orig/arch/powerpc/sysdev/Makefile 2008-01-11 11:45:27.000000000 +1100
+++ working-2.6/arch/powerpc/sysdev/Makefile 2008-01-11 14:17:03.000000000 +1100
@@ -27,6 +27,7 @@ obj-$(CONFIG_PPC_I8259) += i8259.o
obj-$(CONFIG_PPC_83xx) += ipic.o
obj-$(CONFIG_4xx) += uic.o
obj-$(CONFIG_XILINX_VIRTEX) += xilinx_intc.o
+obj-$(CONFIG_OF_RTC) += of_rtc.o
ifeq ($(CONFIG_PCI),y)
obj-$(CONFIG_4xx) += ppc4xx_pci.o
endif
Index: working-2.6/arch/powerpc/sysdev/of_rtc.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ working-2.6/arch/powerpc/sysdev/of_rtc.c 2008-01-11 14:17:03.000000000 +1100
@@ -0,0 +1,59 @@
+/*
+ * Instantiate mmio-mapped RTC chips based on device tree information
+ *
+ * Copyright 2007 David Gibson <dwg at au1.ibm.com>, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/init.h>
+#include <linux/of_platform.h>
+
+static __initdata struct {
+ const char *compatible;
+ char *plat_name;
+} of_rtc_table[] = {
+ { "ds1743-nvram", "rtc-ds1742" },
+};
+
+void __init of_instantiate_rtc(void)
+{
+ struct device_node *node;
+ int err;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(of_rtc_table); i++) {
+ char *plat_name = of_rtc_table[i].plat_name;
+
+ for_each_compatible_node(node, NULL,
+ of_rtc_table[i].compatible) {
+ struct resource *res;
+
+ res = kmalloc(sizeof(*res), GFP_KERNEL);
+ if (!res) {
+ printk(KERN_ERR "OF RTC: Out of memory "
+ "allocating resource structure for %s\n",
+ node->full_name);
+ continue;
+ }
+
+ err = of_address_to_resource(node, 0, res);
+ if (err) {
+ printk(KERN_ERR "OF RTC: Error "
+ "translating resources for %s\n",
+ node->full_name);
+ continue;
+ }
+
+ printk(KERN_INFO "OF_RTC: %s is a %s @ 0x%llx-0x%llx\n",
+ node->full_name, plat_name,
+ (unsigned long long)res->start,
+ (unsigned long long)res->end);
+ platform_device_register_simple(plat_name, -1, res, 1);
+ }
+ }
+}
Index: working-2.6/arch/powerpc/platforms/44x/Kconfig
===================================================================
--- working-2.6.orig/arch/powerpc/platforms/44x/Kconfig 2008-01-11 11:45:27.000000000 +1100
+++ working-2.6/arch/powerpc/platforms/44x/Kconfig 2008-01-11 14:17:03.000000000 +1100
@@ -13,6 +13,7 @@ config EBONY
default y
select 440GP
select PCI
+ select OF_RTC
help
This option enables support for the IBM PPC440GP evaluation board.
Index: working-2.6/include/asm-powerpc/of_platform.h
===================================================================
--- working-2.6.orig/include/asm-powerpc/of_platform.h 2008-01-11 11:45:29.000000000 +1100
+++ working-2.6/include/asm-powerpc/of_platform.h 2008-01-11 14:17:03.000000000 +1100
@@ -37,4 +37,6 @@ extern int of_platform_bus_probe(struct
extern struct of_device *of_find_device_by_phandle(phandle ph);
+extern void of_instantiate_rtc(void);
+
#endif /* _ASM_POWERPC_OF_PLATFORM_H */
Index: working-2.6/arch/powerpc/boot/dts/walnut.dts
===================================================================
--- working-2.6.orig/arch/powerpc/boot/dts/walnut.dts 2008-01-11 11:45:27.000000000 +1100
+++ working-2.6/arch/powerpc/boot/dts/walnut.dts 2008-01-11 14:17:03.000000000 +1100
@@ -175,9 +175,10 @@
};
};
- ds1743 at 1,0 {
+ nvram at 1,0 {
/* NVRAM and RTC */
- compatible = "ds1743";
+ compatible = "ds1743-nvram";
+ #bytes = <2000>;
reg = <1 0 2000>;
};
Index: working-2.6/arch/powerpc/platforms/40x/walnut.c
===================================================================
--- working-2.6.orig/arch/powerpc/platforms/40x/walnut.c 2008-01-11 11:45:27.000000000 +1100
+++ working-2.6/arch/powerpc/platforms/40x/walnut.c 2008-01-11 14:17:03.000000000 +1100
@@ -36,6 +36,7 @@ static __initdata struct of_device_id wa
static int __init walnut_device_probe(void)
{
of_platform_bus_probe(NULL, walnut_of_bus, NULL);
+ of_instantiate_rtc();
return 0;
}
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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