gma500: Add the i2c bus support

/*

 * Copyright © 2006-2007 Intel Corporation

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Authors:

 *	Eric Anholt <eric@anholt.net>

 */

#include <linux/i2c.h>

#include <linux/i2c-algo-bit.h>

#include "psb_drv.h"

#include "psb_intel_reg.h"

/*

 * Intel GPIO access functions

 */

#define I2C_RISEFALL_TIME 20

static int get_clock(void *data)

{

	struct psb_intel_i2c_chan *chan = data;

	struct drm_device *dev = chan->drm_dev;

	u32 val;

	val = REG_READ(chan->reg);

	return (val & GPIO_CLOCK_VAL_IN) != 0;

}

static int get_data(void *data)

{

	struct psb_intel_i2c_chan *chan = data;

	struct drm_device *dev = chan->drm_dev;

	u32 val;

	val = REG_READ(chan->reg);

	return (val & GPIO_DATA_VAL_IN) != 0;

}

static void set_clock(void *data, int state_high)

{

	struct psb_intel_i2c_chan *chan = data;

	struct drm_device *dev = chan->drm_dev;

	u32 reserved = 0, clock_bits;

	/* On most chips, these bits must be preserved in software. */

	reserved =

		    REG_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;

	REG_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 psb_intel_i2c_chan *chan = data;

	struct drm_device *dev = chan->drm_dev;

	u32 reserved = 0, data_bits;

	/* On most chips, these bits must be preserved in software. */

	reserved =

		    REG_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;

	REG_WRITE(chan->reg, reserved | data_bits);

	udelay(I2C_RISEFALL_TIME);	/* wait for the line to change state */

}

/**

 * psb_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 psb_intel_i2c_chan *psb_intel_i2c_create(struct drm_device *dev,

					const u32 reg, const char *name)

{

	struct psb_intel_i2c_chan *chan;

	chan = kzalloc(sizeof(struct psb_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;

	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;

}

/**

 * psb_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 psb_intel_i2c_destroy(struct psb_intel_i2c_chan *chan)

{

	if (!chan)

		return;

	i2c_del_adapter(&chan->adapter);

	kfree(chan);

}