[ARM] Fix i2c-pxa slave mode support

i2c-pxa times out when trying to enable slave mode due to an
incorrect test.  Also, check that i2c->slave is non-NULL
before dereferencing it.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 81050d3c9b21..c95a6c154165 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -272,7 +272,8 @@ static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
                         dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
                                 __func__, (long)jiffies, ISR, ICR, IBMR);
 
-                if ((ISR & (ISR_UB|ISR_IBB|ISR_SAD)) == ISR_SAD ||
+                if ((ISR & (ISR_UB|ISR_IBB)) == 0 ||
+                    (ISR & ISR_SAD) != 0 ||
                     (ICR & ICR_SCLE) == 0) {
                         if (i2c_debug > 1)
                                 dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
@@ -492,7 +493,10 @@ static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
         if (isr & ISR_BED) {
                 /* what should we do here? */
         } else {
-                int ret = i2c->slave->read(i2c->slave->data);
+                int ret = 0;
+
+                if (i2c->slave != NULL)
+                        ret = i2c->slave->read(i2c->slave->data);
 
                 IDBR = ret;
                 ICR |= ICR_TB;   /* allow next byte */