b43legacy: fix bcm4303 crash

This fixes an hard crash which happened upon driver loading on bcm4303 rev.
2 devices.

Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
index bedb2b4ee9d2..72017bf2e577 100644
--- a/drivers/ssb/main.c
+++ b/drivers/ssb/main.c
@@ -1044,6 +1044,12 @@ int ssb_bus_may_powerdown(struct ssb_bus *bus)
                 goto out;
 
         cc = &bus->chipco;
+
+        if (!cc->dev)
+                goto out;
+        if (cc->dev->id.revision < 5)
+                goto out;
+
         ssb_chipco_set_clockmode(cc, SSB_CLKMODE_SLOW);
         err = ssb_pci_xtal(bus, SSB_GPIO_XTAL | SSB_GPIO_PLL, 0);
         if (err)