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Diffstat (limited to 'drivers/gpu/drm/i915/intel_i2c.c')
-rw-r--r--drivers/gpu/drm/i915/intel_i2c.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
new file mode 100644
index 000000000000..5ee9d4c25753
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -0,0 +1,180 @@
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/*
38 * Intel GPIO access functions
39 */
40
41#define I2C_RISEFALL_TIME 20
42
43static int get_clock(void *data)
44{
45 struct intel_i2c_chan *chan = data;
46 struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
47 u32 val;
48
49 val = I915_READ(chan->reg);
50 return ((val & GPIO_CLOCK_VAL_IN) != 0);
51}
52
53static int get_data(void *data)
54{
55 struct intel_i2c_chan *chan = data;
56 struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
57 u32 val;
58
59 val = I915_READ(chan->reg);
60 return ((val & GPIO_DATA_VAL_IN) != 0);
61}
62
63static void set_clock(void *data, int state_high)
64{
65 struct intel_i2c_chan *chan = data;
66 struct drm_device *dev = chan->drm_dev;
67 struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
68 u32 reserved = 0, clock_bits;
69
70 /* On most chips, these bits must be preserved in software. */
71 if (!IS_I830(dev) && !IS_845G(dev))
72 reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
73 GPIO_CLOCK_PULLUP_DISABLE);
74
75 if (state_high)
76 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
77 else
78 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
79 GPIO_CLOCK_VAL_MASK;
80 I915_WRITE(chan->reg, reserved | clock_bits);
81 udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
82}
83
84static void set_data(void *data, int state_high)
85{
86 struct intel_i2c_chan *chan = data;
87 struct drm_device *dev = chan->drm_dev;
88 struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
89 u32 reserved = 0, data_bits;
90
91 /* On most chips, these bits must be preserved in software. */
92 if (!IS_I830(dev) && !IS_845G(dev))
93 reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
94 GPIO_CLOCK_PULLUP_DISABLE);
95
96 if (state_high)
97 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
98 else
99 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
100 GPIO_DATA_VAL_MASK;
101
102 I915_WRITE(chan->reg, reserved | data_bits);
103 udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
104}
105
106/**
107 * intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
108 * @dev: DRM device
109 * @output: driver specific output device
110 * @reg: GPIO reg to use
111 * @name: name for this bus
112 *
113 * Creates and registers a new i2c bus with the Linux i2c layer, for use
114 * in output probing and control (e.g. DDC or SDVO control functions).
115 *
116 * Possible values for @reg include:
117 * %GPIOA
118 * %GPIOB
119 * %GPIOC
120 * %GPIOD
121 * %GPIOE
122 * %GPIOF
123 * %GPIOG
124 * %GPIOH
125 * see PRM for details on how these different busses are used.
126 */
127struct intel_i2c_chan *intel_i2c_create(struct drm_device *dev, const u32 reg,
128 const char *name)
129{
130 struct intel_i2c_chan *chan;
131
132 chan = kzalloc(sizeof(struct intel_i2c_chan), GFP_KERNEL);
133 if (!chan)
134 goto out_free;
135
136 chan->drm_dev = dev;
137 chan->reg = reg;
138 snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
139 chan->adapter.owner = THIS_MODULE;
140 chan->adapter.algo_data = &chan->algo;
141 chan->adapter.dev.parent = &dev->pdev->dev;
142 chan->algo.setsda = set_data;
143 chan->algo.setscl = set_clock;
144 chan->algo.getsda = get_data;
145 chan->algo.getscl = get_clock;
146 chan->algo.udelay = 20;
147 chan->algo.timeout = usecs_to_jiffies(2200);
148 chan->algo.data = chan;
149
150 i2c_set_adapdata(&chan->adapter, chan);
151
152 if(i2c_bit_add_bus(&chan->adapter))
153 goto out_free;
154
155 /* JJJ: raise SCL and SDA? */
156 set_data(chan, 1);
157 set_clock(chan, 1);
158 udelay(20);
159
160 return chan;
161
162out_free:
163 kfree(chan);
164 return NULL;
165}
166
167/**
168 * intel_i2c_destroy - unregister and free i2c bus resources
169 * @output: channel to free
170 *
171 * Unregister the adapter from the i2c layer, then free the structure.
172 */
173void intel_i2c_destroy(struct intel_i2c_chan *chan)
174{
175 if (!chan)
176 return;
177
178 i2c_del_adapter(&chan->adapter);
179 kfree(chan);
180}
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