drm/i915: Change I2C api to pass around i2c_adapters

The existing API passed around intel_i2c_chan pointers, which are dependent
on the i2c bit-banging algo. This precluded the driver from using outputs
which use a different algo. Switching to the more general i2c_adpater allows
the driver to support non bit-banging DDC.

This also required moving the slave address into the output private
structures.

Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/dvo_sil164.c b/drivers/gpu/drm/i915/dvo_sil164.c
index 033a4bb..e1c1f73 100644
--- a/drivers/gpu/drm/i915/dvo_sil164.c
+++ b/drivers/gpu/drm/i915/dvo_sil164.c
@@ -76,19 +76,20 @@
 static bool sil164_readb(struct intel_dvo_device *dvo, int addr, uint8_t *ch)
 {
 	struct sil164_priv *sil = dvo->dev_priv;
-	struct intel_i2c_chan *i2cbus = dvo->i2c_bus;
+	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];
 
 	struct i2c_msg msgs[] = {
 		{
-			.addr = i2cbus->slave_addr,
+			.addr = dvo->slave_addr,
 			.flags = 0,
 			.len = 1,
 			.buf = out_buf,
 		},
 		{
-			.addr = i2cbus->slave_addr,
+			.addr = dvo->slave_addr,
 			.flags = I2C_M_RD,
 			.len = 1,
 			.buf = in_buf,
@@ -105,7 +106,7 @@
 
 	if (!sil->quiet) {
 		DRM_DEBUG("Unable to read register 0x%02x from %s:%02x.\n",
-			  addr, i2cbus->adapter.name, i2cbus->slave_addr);
+			  addr, i2cbus->adapter.name, dvo->slave_addr);
 	}
 	return false;
 }
@@ -113,10 +114,11 @@
 static bool sil164_writeb(struct intel_dvo_device *dvo, int addr, uint8_t ch)
 {
 	struct sil164_priv *sil= dvo->dev_priv;
-	struct intel_i2c_chan *i2cbus = dvo->i2c_bus;
+	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 = i2cbus->slave_addr,
+		.addr = dvo->slave_addr,
 		.flags = 0,
 		.len = 2,
 		.buf = out_buf,
@@ -130,7 +132,7 @@
 
 	if (!sil->quiet) {
 		DRM_DEBUG("Unable to write register 0x%02x to %s:%d.\n",
-			  addr, i2cbus->adapter.name, i2cbus->slave_addr);
+			  addr, i2cbus->adapter.name, dvo->slave_addr);
 	}
 
 	return false;
@@ -138,7 +140,7 @@
 
 /* Silicon Image 164 driver for chip on i2c bus */
 static bool sil164_init(struct intel_dvo_device *dvo,
-			struct intel_i2c_chan *i2cbus)
+			struct i2c_adapter *adapter)
 {
 	/* this will detect the SIL164 chip on the specified i2c bus */
 	struct sil164_priv *sil;
@@ -148,8 +150,7 @@
 	if (sil == NULL)
 		return false;
 
-	dvo->i2c_bus = i2cbus;
-	dvo->i2c_bus->slave_addr = dvo->slave_addr;
+	dvo->i2c_bus = adapter;
 	dvo->dev_priv = sil;
 	sil->quiet = true;
 
@@ -158,7 +159,7 @@
 
 	if (ch != (SIL164_VID & 0xff)) {
 		DRM_DEBUG("sil164 not detected got %d: from %s Slave %d.\n",
-			  ch, i2cbus->adapter.name, i2cbus->slave_addr);
+			  ch, adapter->name, dvo->slave_addr);
 		goto out;
 	}
 
@@ -167,7 +168,7 @@
 
 	if (ch != (SIL164_DID & 0xff)) {
 		DRM_DEBUG("sil164 not detected got %d: from %s Slave %d.\n",
-			  ch, i2cbus->adapter.name, i2cbus->slave_addr);
+			  ch, adapter->name, dvo->slave_addr);
 		goto out;
 	}
 	sil->quiet = false;