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intel_i2c.c
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intel_i2c.c
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/*
* Copyright © 2006-2007 Intel Corporation
*
* 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>
*/
/*
* Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
* Jesse Barnes <jesse.barnes@intel.com>
*/
#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);
}