drm/radeon/kms: add hw_i2c module option

Turn off hw i2c by default except for mm i2c which
is hw only until we sort out the remaining prescale
issues on older chips.  hw i2c can be enabled with
hw_i2c=1.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 10 insertions, 3 deletions

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 1710b9e3ef7..034218c3dbb 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -92,6 +92,7 @@ extern int radeon_new_pll;
 extern int radeon_dynpm;
 extern int radeon_audio;
 extern int radeon_disp_priority;
+extern int radeon_hw_i2c;
 
 /*
  * Copy from radeon_drv.h so we don't have to include both and have conflicting
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 6fd511eec96..055a51732dc 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -93,6 +93,7 @@ int radeon_new_pll = -1;
 int radeon_dynpm = -1;
 int radeon_audio = 1;
 int radeon_disp_priority = 0;
+int radeon_hw_i2c = 0;
 
 MODULE_PARM_DESC(no_wb, "Disable AGP writeback for scratch registers");
 module_param_named(no_wb, radeon_no_wb, int, 0444);
@@ -139,6 +140,9 @@ module_param_named(audio, radeon_audio, int, 0444);
 MODULE_PARM_DESC(disp_priority, "Display Priority (0 = auto, 1 = normal, 2 = high)");
 module_param_named(disp_priority, radeon_disp_priority, int, 0444);
 
+MODULE_PARM_DESC(hw_i2c, "hw i2c engine enable (0 = disable)");
+module_param_named(hw_i2c, radeon_hw_i2c, int, 0444);
+
 static int radeon_suspend(struct drm_device *dev, pm_message_t state)
 {
         drm_radeon_private_t *dev_priv = dev->dev_private;
diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index 352110fd68f..5def6f5dff3 100644
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -879,9 +879,11 @@ struct radeon_i2c_chan *radeon_i2c_create(struct drm_device *dev,
         i2c->adapter.owner = THIS_MODULE;
         i2c->dev = dev;
         i2c_set_adapdata(&i2c->adapter, i2c);
-        if (rec->hw_capable &&
-            ((rdev->family <= CHIP_RS480) ||
-             ((rdev->family >= CHIP_RV515) && (rdev->family <= CHIP_R580)))) {
+        if (rec->mm_i2c ||
+            (rec->hw_capable &&
+             radeon_hw_i2c &&
+             ((rdev->family <= CHIP_RS480) ||
+              ((rdev->family >= CHIP_RV515) && (rdev->family <= CHIP_R580))))) {
                 /* set the radeon hw i2c adapter */
                 sprintf(i2c->adapter.name, "Radeon i2c hw bus %s", name);
                 i2c->adapter.algo = &radeon_i2c_algo;