DRM: i915: add mode setting support

This commit adds i915 driver support for the DRM mode setting APIs.
Currently, VGA, LVDS, SDVO DVI & VGA, TV and DVO LVDS outputs are
supported.  HDMI, DisplayPort and additional SDVO output support will
follow.

Support for the mode setting code is controlled by the new 'modeset'
module option.  A new config option, CONFIG_DRM_I915_KMS controls the
default behavior, and whether a PCI ID list is built into the module for
use by user level module utilities.

Note that if mode setting is enabled, user level drivers that access
display registers directly or that don't use the kernel graphics memory
manager will likely corrupt kernel graphics memory, disrupt output
configuration (possibly leading to hangs and/or blank displays), and
prevent panic/oops messages from appearing.  So use caution when
enabling this code; be sure your user level code supports the new
interfaces.

A new SysRq key, 'g', provides emergency support for switching back to
the kernel's framebuffer console; which is useful for testing.

Co-authors: Dave Airlie <airlied@linux.ie>, Hong Liu <hong.liu@intel.com>

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 184 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
new file mode 100644
index 00000000000..a5a2f5339e9
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
+ * Copyright © 2006-2008 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>
+ */
+#include <linux/i2c.h>
+#include <linux/i2c-id.h>
+#include <linux/i2c-algo-bit.h>
+#include "drmP.h"
+#include "drm.h"
+#include "intel_drv.h"
+#include "i915_drm.h"
+#include "i915_drv.h"
+
+/*
+ * Intel GPIO access functions
+ */
+
+#define I2C_RISEFALL_TIME 20
+
+static int get_clock(void *data)
+{
+	struct intel_i2c_chan *chan = data;
+	struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
+	u32 val;
+
+	val = I915_READ(chan->reg);
+	return ((val & GPIO_CLOCK_VAL_IN) != 0);
+}
+
+static int get_data(void *data)
+{
+	struct intel_i2c_chan *chan = data;
+	struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
+	u32 val;
+
+	val = I915_READ(chan->reg);
+	return ((val & GPIO_DATA_VAL_IN) != 0);
+}
+
+static void set_clock(void *data, int state_high)
+{
+	struct intel_i2c_chan *chan = data;
+	struct drm_device *dev = chan->drm_dev;
+	struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
+	u32 reserved = 0, clock_bits;
+
+	/* On most chips, these bits must be preserved in software. */
+	if (!IS_I830(dev) && !IS_845G(dev))
+		reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
+						   GPIO_CLOCK_PULLUP_DISABLE);
+
+	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(chan->reg, reserved | clock_bits);
+	udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
+}
+
+static void set_data(void *data, int state_high)
+{
+	struct intel_i2c_chan *chan = data;
+	struct drm_device *dev = chan->drm_dev;
+	struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
+	u32 reserved = 0, data_bits;
+
+	/* On most chips, these bits must be preserved in software. */
+	if (!IS_I830(dev) && !IS_845G(dev))
+		reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
+						   GPIO_CLOCK_PULLUP_DISABLE);
+
+	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(chan->reg, reserved | data_bits);
+	udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
+}
+
+/**
+ * intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
+ * @dev: DRM device
+ * @output: driver specific output device
+ * @reg: GPIO reg to use
+ * @name: name for this bus
+ *
+ * Creates and registers a new i2c bus with the Linux i2c layer, for use
+ * in output probing and control (e.g. DDC or SDVO control functions).
+ *
+ * Possible values for @reg include:
+ *   %GPIOA
+ *   %GPIOB
+ *   %GPIOC
+ *   %GPIOD
+ *   %GPIOE
+ *   %GPIOF
+ *   %GPIOG
+ *   %GPIOH
+ * see PRM for details on how these different busses are used.
+ */
+struct intel_i2c_chan *intel_i2c_create(struct drm_device *dev, const u32 reg,
+					const char *name)
+{
+	struct intel_i2c_chan *chan;
+
+	chan = kzalloc(sizeof(struct intel_i2c_chan), GFP_KERNEL);
+	if (!chan)
+		goto out_free;
+
+	chan->drm_dev = dev;
+	chan->reg = reg;
+	snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
+	chan->adapter.owner = THIS_MODULE;
+#ifndef I2C_HW_B_INTELFB
+#define I2C_HW_B_INTELFB I2C_HW_B_I810
+#endif
+	chan->adapter.id = I2C_HW_B_INTELFB;
+	chan->adapter.algo_data	= &chan->algo;
+	chan->adapter.dev.parent = &dev->pdev->dev;
+	chan->algo.setsda = set_data;
+	chan->algo.setscl = set_clock;
+	chan->algo.getsda = get_data;
+	chan->algo.getscl = get_clock;
+	chan->algo.udelay = 20;
+	chan->algo.timeout = usecs_to_jiffies(2200);
+	chan->algo.data = chan;
+
+	i2c_set_adapdata(&chan->adapter, chan);
+
+	if(i2c_bit_add_bus(&chan->adapter))
+		goto out_free;
+
+	/* JJJ:  raise SCL and SDA? */
+	set_data(chan, 1);
+	set_clock(chan, 1);
+	udelay(20);
+
+	return chan;
+
+out_free:
+	kfree(chan);
+	return NULL;
+}
+
+/**
+ * intel_i2c_destroy - unregister and free i2c bus resources
+ * @output: channel to free
+ *
+ * Unregister the adapter from the i2c layer, then free the structure.
+ */
+void intel_i2c_destroy(struct intel_i2c_chan *chan)
+{
+	if (!chan)
+		return;
+
+	i2c_del_adapter(&chan->adapter);
+	kfree(chan);
+}