[PATCH] m68k/mac: Rework patch "use time64_t in RTC handling"

[Finn Thain]

This addresses the issues arising from commit 324caa29cd04
("m68k: mac: use time64_t in RTC handling").

Adopt __u32 for the union in via_read_time(), consistent with changes
to via_write_time().

Use low_32_bits() in via_write_time(), consistent with changes to
pmu_write_time() and cuda_write_time().

Have via_read_time() return a time64_t, consistent with changes to
pmu_read_time and cuda_read_time().

Drop the pointless wraparound conditional in via_read_time().

Cc: Arnd Bergmann <a...@arndb.de>
Signed-off-by: Finn Thain <fth...@telegraphics.com.au>
---
 arch/m68k/mac/misc.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/arch/m68k/mac/misc.c b/arch/m68k/mac/misc.c
index bdc83eac6c61..19e9d8eef1f2 100644
--- a/arch/m68k/mac/misc.c
+++ b/arch/m68k/mac/misc.c
@@ -251,11 +251,11 @@ static void via_write_pram(int offset, __u8 data)
  * is basically any machine with Mac II-style ADB.
  */
 
-static long via_read_time(void)
+static time64_t via_read_time(void)
 {
        union {
                __u8 cdata[4];
-               long idata;
+               __u32 idata;
        } result, last_result;
        int count = 1;
 
@@ -275,12 +275,8 @@ static long via_read_time(void)
                via_pram_command(0x89, &result.cdata[1]);
                via_pram_command(0x8D, &result.cdata[0]);
 
-               if (result.idata == last_result.idata) {
-                       if (result.idata < RTC_OFFSET)
-                               result.idata += 0x100000000ull;
-
-                       return result.idata - RTC_OFFSET;
-               }
+               if (result.idata == last_result.idata)
+                       return (time64_t)result.idata - RTC_OFFSET;
 
                if (++count > 10)
                        break;
@@ -288,8 +284,8 @@ static long via_read_time(void)
                last_result.idata = result.idata;
        }
 
-       pr_err("via_read_time: failed to read a stable value; got 0x%08lx then 
0x%08lx\n",
-              last_result.idata, result.idata);
+       pr_err("%s: failed to read a stable value; got 0x%08x then 0x%08x\n",
+              __func__, last_result.idata, result.idata);
 
        return 0;
 }
@@ -314,7 +310,7 @@ static void via_write_time(time64_t time)
        temp = 0x55;
        via_pram_command(0x35, &temp);
 
-       data.idata = time + RTC_OFFSET;
+       data.idata = lower_32_bits(time + RTC_OFFSET);
        via_pram_command(0x01, &data.cdata[3]);
        via_pram_command(0x05, &data.cdata[2]);
        via_pram_command(0x09, &data.cdata[1]);
-- 
2.16.4