diff options
Diffstat (limited to 'linux-core/intel_i2c.c')
| -rw-r--r-- | linux-core/intel_i2c.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/linux-core/intel_i2c.c b/linux-core/intel_i2c.c new file mode 100644 index 00000000..efcbf656 --- /dev/null +++ b/linux-core/intel_i2c.c @@ -0,0 +1,190 @@ +/* + * 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); +} + + + |