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5091b7eb AC |
1 | /* |
2 | * Copyright © 2006-2007 Intel Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms and conditions of the GNU General Public License, | |
6 | * version 2, as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., | |
15 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | * | |
17 | * Authors: | |
18 | * Eric Anholt <eric@anholt.net> | |
19 | */ | |
af3a2cfb | 20 | #include <linux/export.h> |
5091b7eb AC |
21 | #include <linux/i2c.h> |
22 | #include <linux/i2c-algo-bit.h> | |
23 | ||
24 | #include "psb_drv.h" | |
25 | #include "psb_intel_reg.h" | |
26 | ||
27 | /* | |
28 | * Intel GPIO access functions | |
29 | */ | |
30 | ||
31 | #define I2C_RISEFALL_TIME 20 | |
32 | ||
33 | static int get_clock(void *data) | |
34 | { | |
35 | struct psb_intel_i2c_chan *chan = data; | |
36 | struct drm_device *dev = chan->drm_dev; | |
37 | u32 val; | |
38 | ||
39 | val = REG_READ(chan->reg); | |
40 | return (val & GPIO_CLOCK_VAL_IN) != 0; | |
41 | } | |
42 | ||
43 | static int get_data(void *data) | |
44 | { | |
45 | struct psb_intel_i2c_chan *chan = data; | |
46 | struct drm_device *dev = chan->drm_dev; | |
47 | u32 val; | |
48 | ||
49 | val = REG_READ(chan->reg); | |
50 | return (val & GPIO_DATA_VAL_IN) != 0; | |
51 | } | |
52 | ||
53 | static void set_clock(void *data, int state_high) | |
54 | { | |
55 | struct psb_intel_i2c_chan *chan = data; | |
56 | struct drm_device *dev = chan->drm_dev; | |
57 | u32 reserved = 0, clock_bits; | |
58 | ||
59 | /* On most chips, these bits must be preserved in software. */ | |
60 | reserved = | |
61 | REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE | | |
62 | GPIO_CLOCK_PULLUP_DISABLE); | |
63 | ||
64 | if (state_high) | |
65 | clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK; | |
66 | else | |
67 | clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK | | |
68 | GPIO_CLOCK_VAL_MASK; | |
69 | REG_WRITE(chan->reg, reserved | clock_bits); | |
70 | udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */ | |
71 | } | |
72 | ||
73 | static void set_data(void *data, int state_high) | |
74 | { | |
75 | struct psb_intel_i2c_chan *chan = data; | |
76 | struct drm_device *dev = chan->drm_dev; | |
77 | u32 reserved = 0, data_bits; | |
78 | ||
79 | /* On most chips, these bits must be preserved in software. */ | |
80 | reserved = | |
81 | REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE | | |
82 | GPIO_CLOCK_PULLUP_DISABLE); | |
83 | ||
84 | if (state_high) | |
85 | data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK; | |
86 | else | |
87 | data_bits = | |
88 | GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK | | |
89 | GPIO_DATA_VAL_MASK; | |
90 | ||
91 | REG_WRITE(chan->reg, reserved | data_bits); | |
92 | udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */ | |
93 | } | |
94 | ||
95 | /** | |
96 | * psb_intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg | |
97 | * @dev: DRM device | |
98 | * @output: driver specific output device | |
99 | * @reg: GPIO reg to use | |
100 | * @name: name for this bus | |
101 | * | |
102 | * Creates and registers a new i2c bus with the Linux i2c layer, for use | |
103 | * in output probing and control (e.g. DDC or SDVO control functions). | |
104 | * | |
105 | * Possible values for @reg include: | |
106 | * %GPIOA | |
107 | * %GPIOB | |
108 | * %GPIOC | |
109 | * %GPIOD | |
110 | * %GPIOE | |
111 | * %GPIOF | |
112 | * %GPIOG | |
113 | * %GPIOH | |
114 | * see PRM for details on how these different busses are used. | |
115 | */ | |
116 | struct psb_intel_i2c_chan *psb_intel_i2c_create(struct drm_device *dev, | |
117 | const u32 reg, const char *name) | |
118 | { | |
119 | struct psb_intel_i2c_chan *chan; | |
120 | ||
121 | chan = kzalloc(sizeof(struct psb_intel_i2c_chan), GFP_KERNEL); | |
122 | if (!chan) | |
123 | goto out_free; | |
124 | ||
125 | chan->drm_dev = dev; | |
126 | chan->reg = reg; | |
127 | snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name); | |
128 | chan->adapter.owner = THIS_MODULE; | |
129 | chan->adapter.algo_data = &chan->algo; | |
130 | chan->adapter.dev.parent = &dev->pdev->dev; | |
131 | chan->algo.setsda = set_data; | |
132 | chan->algo.setscl = set_clock; | |
133 | chan->algo.getsda = get_data; | |
134 | chan->algo.getscl = get_clock; | |
135 | chan->algo.udelay = 20; | |
136 | chan->algo.timeout = usecs_to_jiffies(2200); | |
137 | chan->algo.data = chan; | |
138 | ||
139 | i2c_set_adapdata(&chan->adapter, chan); | |
140 | ||
141 | if (i2c_bit_add_bus(&chan->adapter)) | |
142 | goto out_free; | |
143 | ||
144 | /* JJJ: raise SCL and SDA? */ | |
145 | set_data(chan, 1); | |
146 | set_clock(chan, 1); | |
147 | udelay(20); | |
148 | ||
149 | return chan; | |
150 | ||
151 | out_free: | |
152 | kfree(chan); | |
153 | return NULL; | |
154 | } | |
155 | ||
156 | /** | |
157 | * psb_intel_i2c_destroy - unregister and free i2c bus resources | |
158 | * @output: channel to free | |
159 | * | |
160 | * Unregister the adapter from the i2c layer, then free the structure. | |
161 | */ | |
162 | void psb_intel_i2c_destroy(struct psb_intel_i2c_chan *chan) | |
163 | { | |
164 | if (!chan) | |
165 | return; | |
166 | ||
167 | i2c_del_adapter(&chan->adapter); | |
168 | kfree(chan); | |
169 | } |