[PATCH] powerpc: Fix clock spreading setting on some powermacs

The code that sets the clock spreading feature of the Intrepid ASIC
must not be run on some machine models or those won't boot. This
fixes it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 16 insertions, 5 deletions

diff --git a/arch/powerpc/platforms/powermac/feature.c b/arch/powerpc/platforms/powermac/feature.c
index 0d7fa00fcb00..f6e22da2a5da 100644
--- a/arch/powerpc/platforms/powermac/feature.c
+++ b/arch/powerpc/platforms/powermac/feature.c
@@ -1650,11 +1650,19 @@ void pmac_tweak_clock_spreading(int enable)
          */
 
         if (macio->type == macio_intrepid) {
-                if (enable)
-                        UN_OUT(UNI_N_CLOCK_SPREADING, 2);
-                else
-                        UN_OUT(UNI_N_CLOCK_SPREADING, 0);
-                mdelay(40);
+                struct device_node *clock =
+                        of_find_node_by_path("/uni-n@f8000000/hw-clock");
+                if (clock && get_property(clock, "platform-do-clockspreading",
+                                          NULL)) {
+                        printk(KERN_INFO "%sabling clock spreading on Intrepid"
+                               " ASIC\n", enable ? "En" : "Dis");
+                        if (enable)
+                                UN_OUT(UNI_N_CLOCK_SPREADING, 2);
+                        else
+                                UN_OUT(UNI_N_CLOCK_SPREADING, 0);
+                        mdelay(40);
+                }
+                of_node_put(clock);
         }
 
         while (machine_is_compatible("PowerBook5,2") ||
@@ -1724,6 +1732,9 @@ void pmac_tweak_clock_spreading(int enable)
                         pmac_low_i2c_close(ui2c);
                         break;
                 }
+                printk(KERN_INFO "%sabling clock spreading on i2c clock chip\n",
+                       enable ? "En" : "Dis");
+
                 pmac_low_i2c_setmode(ui2c, pmac_low_i2c_mode_stdsub);
                 rc = pmac_low_i2c_xfer(ui2c, 0xd2 | pmac_low_i2c_write, 0x80, buffer, 9);
                 DBG("write result: %d,", rc);