drm/i915: use GMBUS to manage i2c links
Use the GMBUS interface rather than direct bit banging to grab the EDID
over DDC (and for other forms of auxiliary communication with external
display controllers). The hope is that this method will be much faster
and more reliable than bit banging for fetching EDIDs from buggy monitors
or through switches, though we still preserve the bit banging as a
fallback in case GMBUS fails.
Based on an original patch by Jesse Barnes.
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/dvo_ch7xxx.c b/drivers/gpu/drm/i915/dvo_ch7xxx.c
index 6f1944b..7eaa94e 100644
--- a/drivers/gpu/drm/i915/dvo_ch7xxx.c
+++ b/drivers/gpu/drm/i915/dvo_ch7xxx.c
@@ -113,7 +113,6 @@
{
struct ch7xxx_priv *ch7xxx= dvo->dev_priv;
struct i2c_adapter *adapter = dvo->i2c_bus;
- struct intel_i2c_chan *i2cbus = container_of(adapter, struct intel_i2c_chan, adapter);
u8 out_buf[2];
u8 in_buf[2];
@@ -135,14 +134,14 @@
out_buf[0] = addr;
out_buf[1] = 0;
- if (i2c_transfer(&i2cbus->adapter, msgs, 2) == 2) {
+ if (i2c_transfer(adapter, msgs, 2) == 2) {
*ch = in_buf[0];
return true;
};
if (!ch7xxx->quiet) {
DRM_DEBUG_KMS("Unable to read register 0x%02x from %s:%02x.\n",
- addr, i2cbus->adapter.name, dvo->slave_addr);
+ addr, adapter->name, dvo->slave_addr);
}
return false;
}
@@ -152,7 +151,6 @@
{
struct ch7xxx_priv *ch7xxx = dvo->dev_priv;
struct i2c_adapter *adapter = dvo->i2c_bus;
- struct intel_i2c_chan *i2cbus = container_of(adapter, struct intel_i2c_chan, adapter);
uint8_t out_buf[2];
struct i2c_msg msg = {
.addr = dvo->slave_addr,
@@ -164,12 +162,12 @@
out_buf[0] = addr;
out_buf[1] = ch;
- if (i2c_transfer(&i2cbus->adapter, &msg, 1) == 1)
+ if (i2c_transfer(adapter, &msg, 1) == 1)
return true;
if (!ch7xxx->quiet) {
DRM_DEBUG_KMS("Unable to write register 0x%02x to %s:%d.\n",
- addr, i2cbus->adapter.name, dvo->slave_addr);
+ addr, adapter->name, dvo->slave_addr);
}
return false;