[media] drxk: Lock I2C bus during firmware load

Don't allow other devices at the same I2C bus to use it during
firmware load, in order to prevent using the device while it is
not on a sane state.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

2 files changed, 30 insertions, 2 deletions

diff --git a/drivers/media/dvb/frontends/drxk_hard.c b/drivers/media/dvb/frontends/drxk_hard.c
index 5b3a17ce3d1d..87cb3f02ebc0 100644
--- a/drivers/media/dvb/frontends/drxk_hard.c
+++ b/drivers/media/dvb/frontends/drxk_hard.c
@@ -28,6 +28,7 @@
 #include <linux/delay.h>
 #include <linux/firmware.h>
 #include <linux/i2c.h>
+#include <linux/hardirq.h>
 #include <asm/div64.h>
 
 #include "dvb_frontend.h"
@@ -308,10 +309,30 @@ static u32 Log10Times100(u32 x)
 /* I2C **********************************************************************/
 /****************************************************************************/
 
+static int drxk_i2c_lock(struct drxk_state *state)
+{
+        i2c_lock_adapter(state->i2c);
+        state->drxk_i2c_exclusive_lock = true;
+
+        return 0;
+}
+
+static void drxk_i2c_unlock(struct drxk_state *state)
+{
+        if (!state->drxk_i2c_exclusive_lock)
+                return;
+
+        i2c_unlock_adapter(state->i2c);
+        state->drxk_i2c_exclusive_lock = false;
+}
+
 static int drxk_i2c_transfer(struct drxk_state *state, struct i2c_msg *msgs,
                              unsigned len)
 {
-        return i2c_transfer(state->i2c, msgs, len);
+        if (state->drxk_i2c_exclusive_lock)
+                return __i2c_transfer(state->i2c, msgs, len);
+        else
+                return i2c_transfer(state->i2c, msgs, len);
 }
 
 static int i2c_read1(struct drxk_state *state, u8 adr, u8 *val)
@@ -5982,6 +6003,7 @@ static int init_drxk(struct drxk_state *state)
 
         dprintk(1, "\n");
         if ((state->m_DrxkState == DRXK_UNINITIALIZED)) {
+                drxk_i2c_lock(state);
                 status = PowerUpDevice(state);
                 if (status < 0)
                         goto error;
@@ -6171,10 +6193,13 @@ static int init_drxk(struct drxk_state *state)
                         strlcat(state->frontend.ops.info.name, " DVB-T",
                                 sizeof(state->frontend.ops.info.name));
                 }
+                drxk_i2c_unlock(state);
         }
 error:
-        if (status < 0)
+        if (status < 0) {
+                drxk_i2c_unlock(state);
                 printk(KERN_ERR "drxk: Error %d on %s\n", status, __func__);
+        }
 
         return status;
 }
diff --git a/drivers/media/dvb/frontends/drxk_hard.h b/drivers/media/dvb/frontends/drxk_hard.h
index 36677cdc01d8..c35ab2b37795 100644
--- a/drivers/media/dvb/frontends/drxk_hard.h
+++ b/drivers/media/dvb/frontends/drxk_hard.h
@@ -325,6 +325,9 @@ struct drxk_state {
 
         enum DRXPowerMode m_currentPowerMode;
 
+        /* when true, avoids other devices to use the I2C bus */
+        bool              drxk_i2c_exclusive_lock;
+
         /*
          * Configurable parameters at the driver. They stores the values found
          * at struct drxk_config.