drivers/gpu/drm/i915/intel_i2c.c

   1 /*
   2  * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
   3  * Copyright © 2006-2008 Intel Corporation
   4  *   Jesse Barnes <jesse.barnes@intel.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *      Eric Anholt <eric@anholt.net>
  27  */
  28 #include <linux/i2c.h>
  29 #include <linux/i2c-id.h>
  30 #include <linux/i2c-algo-bit.h>
  31 #include "drmP.h"
  32 #include "drm.h"
  33 #include "intel_drv.h"
  34 #include "i915_drm.h"
  35 #include "i915_drv.h"
  36
  37 void intel_i2c_quirk_set(struct drm_device *dev, bool enable)
  38 {
  39         struct drm_i915_private *dev_priv = dev->dev_private;
  40
  41         /* When using bit bashing for I2C, this bit needs to be set to 1 */
  42         if (!IS_IGD(dev))
  43                 return;
  44         if (enable)
  45                 I915_WRITE(CG_2D_DIS,
  46                         I915_READ(CG_2D_DIS) | DPCUNIT_CLOCK_GATE_DISABLE);
  47         else
  48                 I915_WRITE(CG_2D_DIS,
  49                         I915_READ(CG_2D_DIS) & (~DPCUNIT_CLOCK_GATE_DISABLE));
  50 }
  51
  52 /*
  53  * Intel GPIO access functions
  54  */
  55
  56 #define I2C_RISEFALL_TIME 20
  57
  58 static int get_clock(void *data)
  59 {
  60         struct intel_i2c_chan *chan = data;
  61         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
  62         u32 val;
  63
  64         val = I915_READ(chan->reg);
  65         return ((val & GPIO_CLOCK_VAL_IN) != 0);
  66 }
  67
  68 static int get_data(void *data)
  69 {
  70         struct intel_i2c_chan *chan = data;
  71         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
  72         u32 val;
  73
  74         val = I915_READ(chan->reg);
  75         return ((val & GPIO_DATA_VAL_IN) != 0);
  76 }
  77
  78 static void set_clock(void *data, int state_high)
  79 {
  80         struct intel_i2c_chan *chan = data;
  81         struct drm_device *dev = chan->drm_dev;
  82         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
  83         u32 reserved = 0, clock_bits;
  84
  85         /* On most chips, these bits must be preserved in software. */
  86         if (!IS_I830(dev) && !IS_845G(dev))
  87                 reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
  88                                                    GPIO_CLOCK_PULLUP_DISABLE);
  89
  90         if (state_high)
  91                 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
  92         else
  93                 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
  94                         GPIO_CLOCK_VAL_MASK;
  95         I915_WRITE(chan->reg, reserved | clock_bits);
  96         udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
  97 }
  98
  99 static void set_data(void *data, int state_high)
 100 {
 101         struct intel_i2c_chan *chan = data;
 102         struct drm_device *dev = chan->drm_dev;
 103         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
 104         u32 reserved = 0, data_bits;
 105
 106         /* On most chips, these bits must be preserved in software. */
 107         if (!IS_I830(dev) && !IS_845G(dev))
 108                 reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
 109                                                    GPIO_CLOCK_PULLUP_DISABLE);
 110
 111         if (state_high)
 112                 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
 113         else
 114                 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
 115                         GPIO_DATA_VAL_MASK;
 116
 117         I915_WRITE(chan->reg, reserved | data_bits);
 118         udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
 119 }
 120
 121 /**
 122  * intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
 123  * @dev: DRM device
 124  * @output: driver specific output device
 125  * @reg: GPIO reg to use
 126  * @name: name for this bus
 127  *
 128  * Creates and registers a new i2c bus with the Linux i2c layer, for use
 129  * in output probing and control (e.g. DDC or SDVO control functions).
 130  *
 131  * Possible values for @reg include:
 132  *   %GPIOA
 133  *   %GPIOB
 134  *   %GPIOC
 135  *   %GPIOD
 136  *   %GPIOE
 137  *   %GPIOF
 138  *   %GPIOG
 139  *   %GPIOH
 140  * see PRM for details on how these different busses are used.
 141  */
 142 struct intel_i2c_chan *intel_i2c_create(struct drm_device *dev, const u32 reg,
 143                                         const char *name)
 144 {
 145         struct intel_i2c_chan *chan;
 146
 147         chan = kzalloc(sizeof(struct intel_i2c_chan), GFP_KERNEL);
 148         if (!chan)
 149                 goto out_free;
 150
 151         chan->drm_dev = dev;
 152         chan->reg = reg;
 153         snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
 154         chan->adapter.owner = THIS_MODULE;
 155         chan->adapter.algo_data = &chan->algo;
 156         chan->adapter.dev.parent = &dev->pdev->dev;
 157         chan->algo.setsda = set_data;
 158         chan->algo.setscl = set_clock;
 159         chan->algo.getsda = get_data;
 160         chan->algo.getscl = get_clock;
 161         chan->algo.udelay = 20;
 162         chan->algo.timeout = usecs_to_jiffies(2200);
 163         chan->algo.data = chan;
 164
 165         i2c_set_adapdata(&chan->adapter, chan);
 166
 167         if(i2c_bit_add_bus(&chan->adapter))
 168                 goto out_free;
 169
 170         /* JJJ:  raise SCL and SDA? */
 171         intel_i2c_quirk_set(dev, true);
 172         set_data(chan, 1);
 173         set_clock(chan, 1);
 174         intel_i2c_quirk_set(dev, false);
 175         udelay(20);
 176
 177         return chan;
 178
 179 out_free:
 180         kfree(chan);
 181         return NULL;
 182 }
 183
 184 /**
 185  * intel_i2c_destroy - unregister and free i2c bus resources
 186  * @output: channel to free
 187  *
 188  * Unregister the adapter from the i2c layer, then free the structure.
 189  */
 190 void intel_i2c_destroy(struct intel_i2c_chan *chan)
 191 {
 192         if (!chan)
 193                 return;
 194
 195         i2c_del_adapter(&chan->adapter);
 196         kfree(chan);
 197 }