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>

drivers/gpu/drm/drm_edid.c

@@ -30,7 +30,6 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
-#include <linux/i2c-algo-bit.h>
 #include "drmP.h"
 #include "drm_edid.h"
 #include "drm_edid_modes.h"

drivers/gpu/drm/i915/dvo_ch7017.c

@@ -168,7 +168,6 @@ static void ch7017_dpms(struct intel_dvo_device *dvo, int mode);
 static bool ch7017_read(struct intel_dvo_device *dvo, int addr, uint8_t *val)
 {
 	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];
 
@@ -190,7 +189,7 @@ static bool ch7017_read(struct intel_dvo_device *dvo, int addr, uint8_t *val)
 	out_buf[0] = addr;
 	out_buf[1] = 0;
 
-	if (i2c_transfer(&i2cbus->adapter, msgs, 2) == 2) {
+	if (i2c_transfer(adapter, msgs, 2) == 2) {
 		*val= in_buf[0];
 		return true;
 	};
@@ -201,7 +200,6 @@ static bool ch7017_read(struct intel_dvo_device *dvo, int addr, uint8_t *val)
 static bool ch7017_write(struct intel_dvo_device *dvo, int addr, uint8_t val)
 {
 	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,
@@ -213,7 +211,7 @@ static bool ch7017_write(struct intel_dvo_device *dvo, int addr, uint8_t val)
 	out_buf[0] = addr;
 	out_buf[1] = val;
 
-	if (i2c_transfer(&i2cbus->adapter, &msg, 1) == 1)
+	if (i2c_transfer(adapter, &msg, 1) == 1)
 		return true;
 
 	return false;
@@ -223,7 +221,6 @@ static bool ch7017_write(struct intel_dvo_device *dvo, int addr, uint8_t val)
 static bool ch7017_init(struct intel_dvo_device *dvo,
 			struct i2c_adapter *adapter)
 {
-	struct intel_i2c_chan *i2cbus = container_of(adapter, struct intel_i2c_chan, adapter);
 	struct ch7017_priv *priv;
 	uint8_t val;
 
@@ -242,7 +239,7 @@ static bool ch7017_init(struct intel_dvo_device *dvo,
 	    val != CH7019_DEVICE_ID_VALUE) {
 		DRM_DEBUG_KMS("ch701x not detected, got %d: from %s "
 				"Slave %d.\n",
-			  val, i2cbus->adapter.name,dvo->slave_addr);
+			  val, adapter->name,dvo->slave_addr);
 		goto fail;
 	}
 

drivers/gpu/drm/i915/dvo_ch7xxx.c

@@ -113,7 +113,6 @@ static bool ch7xxx_readb(struct intel_dvo_device *dvo, int addr, uint8_t *ch)
 {
 	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 @@ static bool ch7xxx_readb(struct intel_dvo_device *dvo, int addr, uint8_t *ch)
 	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 @@ static bool ch7xxx_writeb(struct intel_dvo_device *dvo, int addr, uint8_t ch)
 {
 	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 @@ static bool ch7xxx_writeb(struct intel_dvo_device *dvo, int addr, uint8_t ch)
 	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;

drivers/gpu/drm/i915/dvo_ivch.c

@@ -167,7 +167,6 @@ static bool ivch_read(struct intel_dvo_device *dvo, int addr, uint16_t *data)
 {
 	struct ivch_priv *priv = 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[1];
 	u8 in_buf[2];
 
@@ -193,15 +192,15 @@ static bool ivch_read(struct intel_dvo_device *dvo, int addr, uint16_t *data)
 
 	out_buf[0] = addr;
 
-	if (i2c_transfer(&i2cbus->adapter, msgs, 3) == 3) {
+	if (i2c_transfer(adapter, msgs, 3) == 3) {
 		*data = (in_buf[1] << 8) | in_buf[0];
 		return true;
 	};
 
 	if (!priv->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;
 }
@@ -211,7 +210,6 @@ static bool ivch_write(struct intel_dvo_device *dvo, int addr, uint16_t data)
 {
 	struct ivch_priv *priv = 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[3];
 	struct i2c_msg msg = {
 		.addr = dvo->slave_addr,
@@ -224,12 +222,12 @@ static bool ivch_write(struct intel_dvo_device *dvo, int addr, uint16_t data)
 	out_buf[1] = data & 0xff;
 	out_buf[2] = data >> 8;
 
-	if (i2c_transfer(&i2cbus->adapter, &msg, 1) == 1)
+	if (i2c_transfer(adapter, &msg, 1) == 1)
 		return true;
 
 	if (!priv->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;

drivers/gpu/drm/i915/dvo_sil164.c

@@ -69,7 +69,6 @@ static bool sil164_readb(struct intel_dvo_device *dvo, int addr, uint8_t *ch)
 {
 	struct sil164_priv *sil = 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];
 
@@ -91,14 +90,14 @@ static bool sil164_readb(struct intel_dvo_device *dvo, int addr, uint8_t *ch)
 	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 (!sil->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;
 }
@@ -107,7 +106,6 @@ static bool sil164_writeb(struct intel_dvo_device *dvo, int addr, uint8_t ch)
 {
 	struct sil164_priv *sil= 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,
@@ -119,12 +117,12 @@ static bool sil164_writeb(struct intel_dvo_device *dvo, int addr, uint8_t ch)
 	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 (!sil->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;

drivers/gpu/drm/i915/dvo_tfp410.c

@@ -94,7 +94,6 @@ static bool tfp410_readb(struct intel_dvo_device *dvo, int addr, uint8_t *ch)
 {
 	struct tfp410_priv *tfp = 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];
 
@@ -116,14 +115,14 @@ static bool tfp410_readb(struct intel_dvo_device *dvo, int addr, uint8_t *ch)
 	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 (!tfp->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;
 }
@@ -132,7 +131,6 @@ static bool tfp410_writeb(struct intel_dvo_device *dvo, int addr, uint8_t ch)
 {
 	struct tfp410_priv *tfp = 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,
@@ -144,12 +142,12 @@ static bool tfp410_writeb(struct intel_dvo_device *dvo, int addr, uint8_t ch)
 	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 (!tfp->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;

drivers/gpu/drm/i915/i915_dma.c

@@ -2001,6 +2001,7 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 
 	/* Try to make sure MCHBAR is enabled before poking at it */
 	intel_setup_mchbar(dev);
+	intel_setup_gmbus(dev);
 	intel_opregion_setup(dev);
 
 	i915_gem_load(dev);
@@ -2155,6 +2156,7 @@ int i915_driver_unload(struct drm_device *dev)
 		intel_cleanup_overlay(dev);
 	}
 
+	intel_teardown_gmbus(dev);
 	intel_teardown_mchbar(dev);
 
 	destroy_workqueue(dev_priv->wq);

drivers/gpu/drm/i915/i915_drv.h

@@ -34,6 +34,7 @@
 #include "intel_bios.h"
 #include "intel_ringbuffer.h"
 #include <linux/io-mapping.h>
+#include <linux/i2c.h>
 #include <drm/intel-gtt.h>
 
 /* General customization:
@@ -246,6 +247,12 @@ typedef struct drm_i915_private {
 
 	void __iomem *regs;
 
+	struct intel_gmbus {
+		struct i2c_adapter adapter;
+		struct i2c_adapter *force_bitbanging;
+		int pin;
+	} *gmbus;
+
 	struct pci_dev *bridge_dev;
 	struct intel_ring_buffer render_ring;
 	struct intel_ring_buffer bsd_ring;
@@ -339,7 +346,7 @@ typedef struct drm_i915_private {
 
 	struct notifier_block lid_notifier;
 
-	int crt_ddc_bus; /* 0 = unknown, else GPIO to use for CRT DDC */
+	int crt_ddc_pin;
 	struct drm_i915_fence_reg fence_regs[16]; /* assume 965 */
 	int fence_reg_start; /* 4 if userland hasn't ioctl'd us yet */
 	int num_fence_regs; /* 8 on pre-965, 16 otherwise */
@@ -1070,6 +1077,11 @@ extern int i915_restore_state(struct drm_device *dev);
 extern int i915_save_state(struct drm_device *dev);
 extern int i915_restore_state(struct drm_device *dev);
 
+/* intel_i2c.c */
+extern int intel_setup_gmbus(struct drm_device *dev);
+extern void intel_teardown_gmbus(struct drm_device *dev);
+extern void intel_i2c_reset(struct drm_device *dev);
+
 /* intel_opregion.c */
 extern int intel_opregion_setup(struct drm_device *dev);
 #ifdef CONFIG_ACPI

drivers/gpu/drm/i915/i915_reg.h

@@ -583,12 +583,51 @@
 # define GPIO_DATA_VAL_IN		(1 << 12)
 # define GPIO_DATA_PULLUP_DISABLE	(1 << 13)
 
-#define GMBUS0			0x5100
-#define GMBUS1			0x5104
-#define GMBUS2			0x5108
-#define GMBUS3			0x510c
-#define GMBUS4			0x5110
-#define GMBUS5			0x5120
+#define GMBUS0			0x5100 /* clock/port select */
+#define   GMBUS_RATE_100KHZ	(0<<8)
+#define   GMBUS_RATE_50KHZ	(1<<8)
+#define   GMBUS_RATE_400KHZ	(2<<8) /* reserved on Pineview */
+#define   GMBUS_RATE_1MHZ	(3<<8) /* reserved on Pineview */
+#define   GMBUS_HOLD_EXT	(1<<7) /* 300ns hold time, rsvd on Pineview */
+#define   GMBUS_PORT_DISABLED	0
+#define   GMBUS_PORT_SSC	1
+#define   GMBUS_PORT_VGADDC	2
+#define   GMBUS_PORT_PANEL	3
+#define   GMBUS_PORT_DPC	4 /* HDMIC */
+#define   GMBUS_PORT_DPB	5 /* SDVO, HDMIB */
+				  /* 6 reserved */
+#define   GMBUS_PORT_DPD	7 /* HDMID */
+#define   GMBUS_NUM_PORTS       8
+#define GMBUS1			0x5104 /* command/status */
+#define   GMBUS_SW_CLR_INT	(1<<31)
+#define   GMBUS_SW_RDY		(1<<30)
+#define   GMBUS_ENT		(1<<29) /* enable timeout */
+#define   GMBUS_CYCLE_NONE	(0<<25)
+#define   GMBUS_CYCLE_WAIT	(1<<25)
+#define   GMBUS_CYCLE_INDEX	(2<<25)
+#define   GMBUS_CYCLE_STOP	(4<<25)
+#define   GMBUS_BYTE_COUNT_SHIFT 16
+#define   GMBUS_SLAVE_INDEX_SHIFT 8
+#define   GMBUS_SLAVE_ADDR_SHIFT 1
+#define   GMBUS_SLAVE_READ	(1<<0)
+#define   GMBUS_SLAVE_WRITE	(0<<0)
+#define GMBUS2			0x5108 /* status */
+#define   GMBUS_INUSE		(1<<15)
+#define   GMBUS_HW_WAIT_PHASE	(1<<14)
+#define   GMBUS_STALL_TIMEOUT	(1<<13)
+#define   GMBUS_INT		(1<<12)
+#define   GMBUS_HW_RDY		(1<<11)
+#define   GMBUS_SATOER		(1<<10)
+#define   GMBUS_ACTIVE		(1<<9)
+#define GMBUS3			0x510c /* data buffer bytes 3-0 */
+#define GMBUS4			0x5110 /* interrupt mask (Pineview+) */
+#define   GMBUS_SLAVE_TIMEOUT_EN (1<<4)
+#define   GMBUS_NAK_EN		(1<<3)
+#define   GMBUS_IDLE_EN		(1<<2)
+#define   GMBUS_HW_WAIT_EN	(1<<1)
+#define   GMBUS_HW_RDY_EN	(1<<0)
+#define GMBUS5			0x5120 /* byte index */
+#define   GMBUS_2BYTE_INDEX_EN	(1<<31)
 
 /*
  * Clock control & power management

drivers/gpu/drm/i915/i915_suspend.c

@@ -860,9 +860,7 @@ int i915_restore_state(struct drm_device *dev)
 	for (i = 0; i < 3; i++)
 		I915_WRITE(SWF30 + (i << 2), dev_priv->saveSWF2[i]);
 
-	/* I2C state */
-	intel_i2c_reset_gmbus(dev);
+	intel_i2c_reset(dev);
 
 	return 0;
 }
-