Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 671 insertions, 0 deletions

diff --git a/kernel/drivers/gpu/drm/i915/intel_i2c.c b/kernel/drivers/gpu/drm/i915/intel_i2c.c
new file mode 100644
index 000000000..ae628001f
--- /dev/null
+++ b/kernel/drivers/gpu/drm/i915/intel_i2c.c
@@ -0,0 +1,671 @@
+/*
+ * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
+ * Copyright © 2006-2008,2010 Intel Corporation
+ *   Jesse Barnes <jesse.barnes@intel.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *	Eric Anholt <eric@anholt.net>
+ *	Chris Wilson <chris@chris-wilson.co.uk>
+ */
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include <linux/export.h>
+#include <drm/drmP.h>
+#include "intel_drv.h"
+#include <drm/i915_drm.h>
+#include "i915_drv.h"
+
+struct gmbus_port {
+	const char *name;
+	int reg;
+};
+
+static const struct gmbus_port gmbus_ports[] = {
+	{ "ssc", GPIOB },
+	{ "vga", GPIOA },
+	{ "panel", GPIOC },
+	{ "dpc", GPIOD },
+	{ "dpb", GPIOE },
+	{ "dpd", GPIOF },
+};
+
+/* Intel GPIO access functions */
+
+#define I2C_RISEFALL_TIME 10
+
+static inline struct intel_gmbus *
+to_intel_gmbus(struct i2c_adapter *i2c)
+{
+	return container_of(i2c, struct intel_gmbus, adapter);
+}
+
+void
+intel_i2c_reset(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	I915_WRITE(dev_priv->gpio_mmio_base + GMBUS0, 0);
+	I915_WRITE(dev_priv->gpio_mmio_base + GMBUS4, 0);
+}
+
+static void intel_i2c_quirk_set(struct drm_i915_private *dev_priv, bool enable)
+{
+	u32 val;
+
+	/* When using bit bashing for I2C, this bit needs to be set to 1 */
+	if (!IS_PINEVIEW(dev_priv->dev))
+		return;
+
+	val = I915_READ(DSPCLK_GATE_D);
+	if (enable)
+		val |= DPCUNIT_CLOCK_GATE_DISABLE;
+	else
+		val &= ~DPCUNIT_CLOCK_GATE_DISABLE;
+	I915_WRITE(DSPCLK_GATE_D, val);
+}
+
+static u32 get_reserved(struct intel_gmbus *bus)
+{
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+	struct drm_device *dev = dev_priv->dev;
+	u32 reserved = 0;
+
+	/* On most chips, these bits must be preserved in software. */
+	if (!IS_I830(dev) && !IS_845G(dev))
+		reserved = I915_READ_NOTRACE(bus->gpio_reg) &
+					     (GPIO_DATA_PULLUP_DISABLE |
+					      GPIO_CLOCK_PULLUP_DISABLE);
+
+	return reserved;
+}
+
+static int get_clock(void *data)
+{
+	struct intel_gmbus *bus = data;
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+	u32 reserved = get_reserved(bus);
+	I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_CLOCK_DIR_MASK);
+	I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
+	return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_CLOCK_VAL_IN) != 0;
+}
+
+static int get_data(void *data)
+{
+	struct intel_gmbus *bus = data;
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+	u32 reserved = get_reserved(bus);
+	I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_DATA_DIR_MASK);
+	I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
+	return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_DATA_VAL_IN) != 0;
+}
+
+static void set_clock(void *data, int state_high)
+{
+	struct intel_gmbus *bus = data;
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+	u32 reserved = get_reserved(bus);
+	u32 clock_bits;
+
+	if (state_high)
+		clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
+	else
+		clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
+			GPIO_CLOCK_VAL_MASK;
+
+	I915_WRITE_NOTRACE(bus->gpio_reg, reserved | clock_bits);
+	POSTING_READ(bus->gpio_reg);
+}
+
+static void set_data(void *data, int state_high)
+{
+	struct intel_gmbus *bus = data;
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+	u32 reserved = get_reserved(bus);
+	u32 data_bits;
+
+	if (state_high)
+		data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
+	else
+		data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
+			GPIO_DATA_VAL_MASK;
+
+	I915_WRITE_NOTRACE(bus->gpio_reg, reserved | data_bits);
+	POSTING_READ(bus->gpio_reg);
+}
+
+static int
+intel_gpio_pre_xfer(struct i2c_adapter *adapter)
+{
+	struct intel_gmbus *bus = container_of(adapter,
+					       struct intel_gmbus,
+					       adapter);
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+
+	intel_i2c_reset(dev_priv->dev);
+	intel_i2c_quirk_set(dev_priv, true);
+	set_data(bus, 1);
+	set_clock(bus, 1);
+	udelay(I2C_RISEFALL_TIME);
+	return 0;
+}
+
+static void
+intel_gpio_post_xfer(struct i2c_adapter *adapter)
+{
+	struct intel_gmbus *bus = container_of(adapter,
+					       struct intel_gmbus,
+					       adapter);
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+
+	set_data(bus, 1);
+	set_clock(bus, 1);
+	intel_i2c_quirk_set(dev_priv, false);
+}
+
+static void
+intel_gpio_setup(struct intel_gmbus *bus, u32 pin)
+{
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+	struct i2c_algo_bit_data *algo;
+
+	algo = &bus->bit_algo;
+
+	/* -1 to map pin pair to gmbus index */
+	bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_ports[pin - 1].reg;
+
+	bus->adapter.algo_data = algo;
+	algo->setsda = set_data;
+	algo->setscl = set_clock;
+	algo->getsda = get_data;
+	algo->getscl = get_clock;
+	algo->pre_xfer = intel_gpio_pre_xfer;
+	algo->post_xfer = intel_gpio_post_xfer;
+	algo->udelay = I2C_RISEFALL_TIME;
+	algo->timeout = usecs_to_jiffies(2200);
+	algo->data = bus;
+}
+
+static int
+gmbus_wait_hw_status(struct drm_i915_private *dev_priv,
+		     u32 gmbus2_status,
+		     u32 gmbus4_irq_en)
+{
+	int i;
+	int reg_offset = dev_priv->gpio_mmio_base;
+	u32 gmbus2 = 0;
+	DEFINE_WAIT(wait);
+
+	if (!HAS_GMBUS_IRQ(dev_priv->dev))
+		gmbus4_irq_en = 0;
+
+	/* Important: The hw handles only the first bit, so set only one! Since
+	 * we also need to check for NAKs besides the hw ready/idle signal, we
+	 * need to wake up periodically and check that ourselves. */
+	I915_WRITE(GMBUS4 + reg_offset, gmbus4_irq_en);
+
+	for (i = 0; i < msecs_to_jiffies_timeout(50); i++) {
+		prepare_to_wait(&dev_priv->gmbus_wait_queue, &wait,
+				TASK_UNINTERRUPTIBLE);
+
+		gmbus2 = I915_READ_NOTRACE(GMBUS2 + reg_offset);
+		if (gmbus2 & (GMBUS_SATOER | gmbus2_status))
+			break;
+
+		schedule_timeout(1);
+	}
+	finish_wait(&dev_priv->gmbus_wait_queue, &wait);
+
+	I915_WRITE(GMBUS4 + reg_offset, 0);
+
+	if (gmbus2 & GMBUS_SATOER)
+		return -ENXIO;
+	if (gmbus2 & gmbus2_status)
+		return 0;
+	return -ETIMEDOUT;
+}
+
+static int
+gmbus_wait_idle(struct drm_i915_private *dev_priv)
+{
+	int ret;
+	int reg_offset = dev_priv->gpio_mmio_base;
+
+#define C ((I915_READ_NOTRACE(GMBUS2 + reg_offset) & GMBUS_ACTIVE) == 0)
+
+	if (!HAS_GMBUS_IRQ(dev_priv->dev))
+		return wait_for(C, 10);
+
+	/* Important: The hw handles only the first bit, so set only one! */
+	I915_WRITE(GMBUS4 + reg_offset, GMBUS_IDLE_EN);
+
+	ret = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
+				 msecs_to_jiffies_timeout(10));
+
+	I915_WRITE(GMBUS4 + reg_offset, 0);
+
+	if (ret)
+		return 0;
+	else
+		return -ETIMEDOUT;
+#undef C
+}
+
+static int
+gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv,
+		      unsigned short addr, u8 *buf, unsigned int len,
+		      u32 gmbus1_index)
+{
+	int reg_offset = dev_priv->gpio_mmio_base;
+
+	I915_WRITE(GMBUS1 + reg_offset,
+		   gmbus1_index |
+		   GMBUS_CYCLE_WAIT |
+		   (len << GMBUS_BYTE_COUNT_SHIFT) |
+		   (addr << GMBUS_SLAVE_ADDR_SHIFT) |
+		   GMBUS_SLAVE_READ | GMBUS_SW_RDY);
+	while (len) {
+		int ret;
+		u32 val, loop = 0;
+
+		ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY,
+					   GMBUS_HW_RDY_EN);
+		if (ret)
+			return ret;
+
+		val = I915_READ(GMBUS3 + reg_offset);
+		do {
+			*buf++ = val & 0xff;
+			val >>= 8;
+		} while (--len && ++loop < 4);
+	}
+
+	return 0;
+}
+
+static int
+gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
+		u32 gmbus1_index)
+{
+	u8 *buf = msg->buf;
+	unsigned int rx_size = msg->len;
+	unsigned int len;
+	int ret;
+
+	do {
+		len = min(rx_size, GMBUS_BYTE_COUNT_MAX);
+
+		ret = gmbus_xfer_read_chunk(dev_priv, msg->addr,
+					    buf, len, gmbus1_index);
+		if (ret)
+			return ret;
+
+		rx_size -= len;
+		buf += len;
+	} while (rx_size != 0);
+
+	return 0;
+}
+
+static int
+gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv,
+		       unsigned short addr, u8 *buf, unsigned int len)
+{
+	int reg_offset = dev_priv->gpio_mmio_base;
+	unsigned int chunk_size = len;
+	u32 val, loop;
+
+	val = loop = 0;
+	while (len && loop < 4) {
+		val |= *buf++ << (8 * loop++);
+		len -= 1;
+	}
+
+	I915_WRITE(GMBUS3 + reg_offset, val);
+	I915_WRITE(GMBUS1 + reg_offset,
+		   GMBUS_CYCLE_WAIT |
+		   (chunk_size << GMBUS_BYTE_COUNT_SHIFT) |
+		   (addr << GMBUS_SLAVE_ADDR_SHIFT) |
+		   GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
+	while (len) {
+		int ret;
+
+		val = loop = 0;
+		do {
+			val |= *buf++ << (8 * loop);
+		} while (--len && ++loop < 4);
+
+		I915_WRITE(GMBUS3 + reg_offset, val);
+
+		ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY,
+					   GMBUS_HW_RDY_EN);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int
+gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg)
+{
+	u8 *buf = msg->buf;
+	unsigned int tx_size = msg->len;
+	unsigned int len;
+	int ret;
+
+	do {
+		len = min(tx_size, GMBUS_BYTE_COUNT_MAX);
+
+		ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len);
+		if (ret)
+			return ret;
+
+		buf += len;
+		tx_size -= len;
+	} while (tx_size != 0);
+
+	return 0;
+}
+
+/*
+ * The gmbus controller can combine a 1 or 2 byte write with a read that
+ * immediately follows it by using an "INDEX" cycle.
+ */
+static bool
+gmbus_is_index_read(struct i2c_msg *msgs, int i, int num)
+{
+	return (i + 1 < num &&
+		!(msgs[i].flags & I2C_M_RD) && msgs[i].len <= 2 &&
+		(msgs[i + 1].flags & I2C_M_RD));
+}
+
+static int
+gmbus_xfer_index_read(struct drm_i915_private *dev_priv, struct i2c_msg *msgs)
+{
+	int reg_offset = dev_priv->gpio_mmio_base;
+	u32 gmbus1_index = 0;
+	u32 gmbus5 = 0;
+	int ret;
+
+	if (msgs[0].len == 2)
+		gmbus5 = GMBUS_2BYTE_INDEX_EN |
+			 msgs[0].buf[1] | (msgs[0].buf[0] << 8);
+	if (msgs[0].len == 1)
+		gmbus1_index = GMBUS_CYCLE_INDEX |
+			       (msgs[0].buf[0] << GMBUS_SLAVE_INDEX_SHIFT);
+
+	/* GMBUS5 holds 16-bit index */
+	if (gmbus5)
+		I915_WRITE(GMBUS5 + reg_offset, gmbus5);
+
+	ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus1_index);
+
+	/* Clear GMBUS5 after each index transfer */
+	if (gmbus5)
+		I915_WRITE(GMBUS5 + reg_offset, 0);
+
+	return ret;
+}
+
+static int
+gmbus_xfer(struct i2c_adapter *adapter,
+	   struct i2c_msg *msgs,
+	   int num)
+{
+	struct intel_gmbus *bus = container_of(adapter,
+					       struct intel_gmbus,
+					       adapter);
+	struct drm_i915_private *dev_priv = bus->dev_priv;
+	int i = 0, inc, try = 0, reg_offset;
+	int ret = 0;
+
+	intel_aux_display_runtime_get(dev_priv);
+	mutex_lock(&dev_priv->gmbus_mutex);
+
+	if (bus->force_bit) {
+		ret = i2c_bit_algo.master_xfer(adapter, msgs, num);
+		goto out;
+	}
+
+	reg_offset = dev_priv->gpio_mmio_base;
+
+retry:
+	I915_WRITE(GMBUS0 + reg_offset, bus->reg0);
+
+	for (; i < num; i += inc) {
+		inc = 1;
+		if (gmbus_is_index_read(msgs, i, num)) {
+			ret = gmbus_xfer_index_read(dev_priv, &msgs[i]);
+			inc = 2; /* an index read is two msgs */
+		} else if (msgs[i].flags & I2C_M_RD) {
+			ret = gmbus_xfer_read(dev_priv, &msgs[i], 0);
+		} else {
+			ret = gmbus_xfer_write(dev_priv, &msgs[i]);
+		}
+
+		if (ret == -ETIMEDOUT)
+			goto timeout;
+		if (ret == -ENXIO)
+			goto clear_err;
+
+		ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_WAIT_PHASE,
+					   GMBUS_HW_WAIT_EN);
+		if (ret == -ENXIO)
+			goto clear_err;
+		if (ret)
+			goto timeout;
+	}
+
+	/* Generate a STOP condition on the bus. Note that gmbus can't generata
+	 * a STOP on the very first cycle. To simplify the code we
+	 * unconditionally generate the STOP condition with an additional gmbus
+	 * cycle. */
+	I915_WRITE(GMBUS1 + reg_offset, GMBUS_CYCLE_STOP | GMBUS_SW_RDY);
+
+	/* Mark the GMBUS interface as disabled after waiting for idle.
+	 * We will re-enable it at the start of the next xfer,
+	 * till then let it sleep.
+	 */
+	if (gmbus_wait_idle(dev_priv)) {
+		DRM_DEBUG_KMS("GMBUS [%s] timed out waiting for idle\n",
+			 adapter->name);
+		ret = -ETIMEDOUT;
+	}
+	I915_WRITE(GMBUS0 + reg_offset, 0);
+	ret = ret ?: i;
+	goto out;
+
+clear_err:
+	/*
+	 * Wait for bus to IDLE before clearing NAK.
+	 * If we clear the NAK while bus is still active, then it will stay
+	 * active and the next transaction may fail.
+	 *
+	 * If no ACK is received during the address phase of a transaction, the
+	 * adapter must report -ENXIO. It is not clear what to return if no ACK
+	 * is received at other times. But we have to be careful to not return
+	 * spurious -ENXIO because that will prevent i2c and drm edid functions
+	 * from retrying. So return -ENXIO only when gmbus properly quiescents -
+	 * timing out seems to happen when there _is_ a ddc chip present, but
+	 * it's slow responding and only answers on the 2nd retry.
+	 */
+	ret = -ENXIO;
+	if (gmbus_wait_idle(dev_priv)) {
+		DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",
+			      adapter->name);
+		ret = -ETIMEDOUT;
+	}
+
+	/* Toggle the Software Clear Interrupt bit. This has the effect
+	 * of resetting the GMBUS controller and so clearing the
+	 * BUS_ERROR raised by the slave's NAK.
+	 */
+	I915_WRITE(GMBUS1 + reg_offset, GMBUS_SW_CLR_INT);
+	I915_WRITE(GMBUS1 + reg_offset, 0);
+	I915_WRITE(GMBUS0 + reg_offset, 0);
+
+	DRM_DEBUG_KMS("GMBUS [%s] NAK for addr: %04x %c(%d)\n",
+			 adapter->name, msgs[i].addr,
+			 (msgs[i].flags & I2C_M_RD) ? 'r' : 'w', msgs[i].len);
+
+	/*
+	 * Passive adapters sometimes NAK the first probe. Retry the first
+	 * message once on -ENXIO for GMBUS transfers; the bit banging algorithm
+	 * has retries internally. See also the retry loop in
+	 * drm_do_probe_ddc_edid, which bails out on the first -ENXIO.
+	 */
+	if (ret == -ENXIO && i == 0 && try++ == 0) {
+		DRM_DEBUG_KMS("GMBUS [%s] NAK on first message, retry\n",
+			      adapter->name);
+		goto retry;
+	}
+
+	goto out;
+
+timeout:
+	DRM_INFO("GMBUS [%s] timed out, falling back to bit banging on pin %d\n",
+		 bus->adapter.name, bus->reg0 & 0xff);
+	I915_WRITE(GMBUS0 + reg_offset, 0);
+
+	/* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
+	bus->force_bit = 1;
+	ret = i2c_bit_algo.master_xfer(adapter, msgs, num);
+
+out:
+	mutex_unlock(&dev_priv->gmbus_mutex);
+	intel_aux_display_runtime_put(dev_priv);
+	return ret;
+}
+
+static u32 gmbus_func(struct i2c_adapter *adapter)
+{
+	return i2c_bit_algo.functionality(adapter) &
+		(I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
+		/* I2C_FUNC_10BIT_ADDR | */
+		I2C_FUNC_SMBUS_READ_BLOCK_DATA |
+		I2C_FUNC_SMBUS_BLOCK_PROC_CALL);
+}
+
+static const struct i2c_algorithm gmbus_algorithm = {
+	.master_xfer	= gmbus_xfer,
+	.functionality	= gmbus_func
+};
+
+/**
+ * intel_gmbus_setup - instantiate all Intel i2c GMBuses
+ * @dev: DRM device
+ */
+int intel_setup_gmbus(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int ret, i;
+
+	if (HAS_PCH_NOP(dev))
+		return 0;
+	else if (HAS_PCH_SPLIT(dev))
+		dev_priv->gpio_mmio_base = PCH_GPIOA - GPIOA;
+	else if (IS_VALLEYVIEW(dev))
+		dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE;
+	else
+		dev_priv->gpio_mmio_base = 0;
+
+	mutex_init(&dev_priv->gmbus_mutex);
+	init_waitqueue_head(&dev_priv->gmbus_wait_queue);
+
+	for (i = 0; i < GMBUS_NUM_PORTS; i++) {
+		struct intel_gmbus *bus = &dev_priv->gmbus[i];
+		u32 port = i + 1; /* +1 to map gmbus index to pin pair */
+
+		bus->adapter.owner = THIS_MODULE;
+		bus->adapter.class = I2C_CLASS_DDC;
+		snprintf(bus->adapter.name,
+			 sizeof(bus->adapter.name),
+			 "i915 gmbus %s",
+			 gmbus_ports[i].name);
+
+		bus->adapter.dev.parent = &dev->pdev->dev;
+		bus->dev_priv = dev_priv;
+
+		bus->adapter.algo = &gmbus_algorithm;
+
+		/* By default use a conservative clock rate */
+		bus->reg0 = port | GMBUS_RATE_100KHZ;
+
+		/* gmbus seems to be broken on i830 */
+		if (IS_I830(dev))
+			bus->force_bit = 1;
+
+		intel_gpio_setup(bus, port);
+
+		ret = i2c_add_adapter(&bus->adapter);
+		if (ret)
+			goto err;
+	}
+
+	intel_i2c_reset(dev_priv->dev);
+
+	return 0;
+
+err:
+	while (--i) {
+		struct intel_gmbus *bus = &dev_priv->gmbus[i];
+		i2c_del_adapter(&bus->adapter);
+	}
+	return ret;
+}
+
+struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
+					    unsigned port)
+{
+	WARN_ON(!intel_gmbus_is_port_valid(port));
+	/* -1 to map pin pair to gmbus index */
+	return (intel_gmbus_is_port_valid(port)) ?
+		&dev_priv->gmbus[port - 1].adapter : NULL;
+}
+
+void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
+{
+	struct intel_gmbus *bus = to_intel_gmbus(adapter);
+
+	bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed;
+}
+
+void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
+{
+	struct intel_gmbus *bus = to_intel_gmbus(adapter);
+
+	bus->force_bit += force_bit ? 1 : -1;
+	DRM_DEBUG_KMS("%sabling bit-banging on %s. force bit now %d\n",
+		      force_bit ? "en" : "dis", adapter->name,
+		      bus->force_bit);
+}
+
+void intel_teardown_gmbus(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int i;
+
+	for (i = 0; i < GMBUS_NUM_PORTS; i++) {
+		struct intel_gmbus *bus = &dev_priv->gmbus[i];
+		i2c_del_adapter(&bus->adapter);
+	}
+}