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/slab.h>
  30 #include <linux/i2c-id.h>
  31 #include <linux/i2c-algo-bit.h>
  32 #include "drmP.h"
  33 #include "drm.h"
  34 #include "intel_drv.h"
  35 #include "i915_drm.h"
  36 #include "i915_drv.h"
  37
  38 void intel_i2c_quirk_set(struct drm_device *dev, bool enable)
  39 {
  40         struct drm_i915_private *dev_priv = dev->dev_private;
  41
  42         /* When using bit bashing for I2C, this bit needs to be set to 1 */
  43         if (!IS_PINEVIEW(dev))
  44                 return;
  45         if (enable)
  46                 I915_WRITE(DSPCLK_GATE_D,
  47                         I915_READ(DSPCLK_GATE_D) | DPCUNIT_CLOCK_GATE_DISABLE);
  48         else
  49                 I915_WRITE(DSPCLK_GATE_D,
  50                         I915_READ(DSPCLK_GATE_D) & (~DPCUNIT_CLOCK_GATE_DISABLE));
  51 }
  52
  53 /*
  54  * Intel GPIO access functions
  55  */
  56
  57 #define I2C_RISEFALL_TIME 20
  58
  59 static int get_clock(void *data)
  60 {
  61         struct intel_i2c_chan *chan = data;
  62         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
  63         u32 val;
  64
  65         val = I915_READ(chan->reg);
  66         return ((val & GPIO_CLOCK_VAL_IN) != 0);
  67 }
  68
  69 static int get_data(void *data)
  70 {
  71         struct intel_i2c_chan *chan = data;
  72         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
  73         u32 val;
  74
  75         val = I915_READ(chan->reg);
  76         return ((val & GPIO_DATA_VAL_IN) != 0);
  77 }
  78
  79 static void set_clock(void *data, int state_high)
  80 {
  81         struct intel_i2c_chan *chan = data;
  82         struct drm_device *dev = chan->drm_dev;
  83         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
  84         u32 reserved = 0, clock_bits;
  85
  86         /* On most chips, these bits must be preserved in software. */
  87         if (!IS_I830(dev) && !IS_845G(dev))
  88                 reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
  89                                                    GPIO_CLOCK_PULLUP_DISABLE);
  90
  91         if (state_high)
  92                 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
  93         else
  94                 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
  95                         GPIO_CLOCK_VAL_MASK;
  96         I915_WRITE(chan->reg, reserved | clock_bits);
  97         udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
  98 }
  99
 100 static void set_data(void *data, int state_high)
 101 {
 102         struct intel_i2c_chan *chan = data;
 103         struct drm_device *dev = chan->drm_dev;
 104         struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
 105         u32 reserved = 0, data_bits;
 106
 107         /* On most chips, these bits must be preserved in software. */
 108         if (!IS_I830(dev) && !IS_845G(dev))
 109                 reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
 110                                                    GPIO_CLOCK_PULLUP_DISABLE);
 111
 112         if (state_high)
 113                 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
 114         else
 115                 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
 116                         GPIO_DATA_VAL_MASK;
 117
 118         I915_WRITE(chan->reg, reserved | data_bits);
 119         udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
 120 }
 121
 122 /* Clears the GMBUS setup.  Our driver doesn't make use of the GMBUS I2C
 123  * engine, but if the BIOS leaves it enabled, then that can break our use
 124  * of the bit-banging I2C interfaces.  This is notably the case with the
 125  * Mac Mini in EFI mode.
 126  */
 127 void
 128 intel_i2c_reset_gmbus(struct drm_device *dev)
 129 {
 130         struct drm_i915_private *dev_priv = dev->dev_private;
 131
 132         if (HAS_PCH_SPLIT(dev)) {
 133                 I915_WRITE(PCH_GMBUS0, 0);
 134         } else {
 135                 I915_WRITE(GMBUS0, 0);
 136         }
 137 }
 138
 139 /**
 140  * intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
 141  * @dev: DRM device
 142  * @output: driver specific output device
 143  * @reg: GPIO reg to use
 144  * @name: name for this bus
 145  * @slave_addr: slave address (if fixed)
 146  *
 147  * Creates and registers a new i2c bus with the Linux i2c layer, for use
 148  * in output probing and control (e.g. DDC or SDVO control functions).
 149  *
 150  * Possible values for @reg include:
 151  *   %GPIOA
 152  *   %GPIOB
 153  *   %GPIOC
 154  *   %GPIOD
 155  *   %GPIOE
 156  *   %GPIOF
 157  *   %GPIOG
 158  *   %GPIOH
 159  * see PRM for details on how these different busses are used.
 160  */
 161 struct i2c_adapter *intel_i2c_create(struct drm_device *dev, const u32 reg,
 162                                      const char *name)
 163 {
 164         struct intel_i2c_chan *chan;
 165
 166         chan = kzalloc(sizeof(struct intel_i2c_chan), GFP_KERNEL);
 167         if (!chan)
 168                 goto out_free;
 169
 170         chan->drm_dev = dev;
 171         chan->reg = reg;
 172         snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
 173         chan->adapter.owner = THIS_MODULE;
 174         chan->adapter.algo_data = &chan->algo;
 175         chan->adapter.dev.parent = &dev->pdev->dev;
 176         chan->algo.setsda = set_data;
 177         chan->algo.setscl = set_clock;
 178         chan->algo.getsda = get_data;
 179         chan->algo.getscl = get_clock;
 180         chan->algo.udelay = 20;
 181         chan->algo.timeout = usecs_to_jiffies(2200);
 182         chan->algo.data = chan;
 183
 184         i2c_set_adapdata(&chan->adapter, chan);
 185
 186         if(i2c_bit_add_bus(&chan->adapter))
 187                 goto out_free;
 188
 189         intel_i2c_reset_gmbus(dev);
 190
 191         /* JJJ:  raise SCL and SDA? */
 192         intel_i2c_quirk_set(dev, true);
 193         set_data(chan, 1);
 194         set_clock(chan, 1);
 195         intel_i2c_quirk_set(dev, false);
 196         udelay(20);
 197
 198         return &chan->adapter;
 199
 200 out_free:
 201         kfree(chan);
 202         return NULL;
 203 }
 204
 205 /**
 206  * intel_i2c_destroy - unregister and free i2c bus resources
 207  * @output: channel to free
 208  *
 209  * Unregister the adapter from the i2c layer, then free the structure.
 210  */
 211 void intel_i2c_destroy(struct i2c_adapter *adapter)
 212 {
 213         struct intel_i2c_chan *chan;
 214
 215         if (!adapter)
 216                 return;
 217
 218         chan = container_of(adapter,
 219                             struct intel_i2c_chan,
 220                             adapter);
 221         i2c_del_adapter(&chan->adapter);
 222         kfree(chan);
 223 }