x86: rtc: don't register a platform RTC device for Intel MID platforms

Intel MID x86 platforms have a memory mapped virtual RTC instead.  No MID
platform have the default ports (and accessing them may do weird stuff)

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <>

diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h
index 719f00b28ff5358caf87d736ed5b4100dafdce9e..2f2186438bf8f1b89ac5c82239041d824070591f 100644 (file)
--- a/arch/x86/include/asm/mrst.h
+++ b/arch/x86/include/asm/mrst.h
@@ -31,11 +31,20 @@ enum mrst_cpu_type {
 };
 
 extern enum mrst_cpu_type __mrst_cpu_chip;
+
+#ifdef CONFIG_X86_INTEL_MID
+
 static inline enum mrst_cpu_type mrst_identify_cpu(void)
 {
        return __mrst_cpu_chip;
 }
 
+#else /* !CONFIG_X86_INTEL_MID */
+
+#define mrst_identify_cpu()    (0)
+
+#endif /* !CONFIG_X86_INTEL_MID */
+
 enum mrst_timer_options {
        MRST_TIMER_DEFAULT,
        MRST_TIMER_APBT_ONLY,

diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 348ce016a835c291deeae528fb327ea8f93ffbdb..af6db6ec5b2a20db3d13861bdb97b878f8371f1e 100644 (file)
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -12,6 +12,7 @@
 #include <asm/vsyscall.h>
 #include <asm/x86_init.h>
 #include <asm/time.h>
+#include <asm/mrst.h>
 
 #ifdef CONFIG_X86_32
 /*
@@ -242,6 +243,10 @@ static __init int add_rtc_cmos(void)
        if (of_have_populated_dt())
                return 0;
 
+       /* Intel MID platforms don't have ioport rtc */
+       if (mrst_identify_cpu())
+               return -ENODEV;
+
        platform_device_register(&rtc_device);
        dev_info(&rtc_device.dev,
                 "registered platform RTC device (no PNP device found)\n");