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 */
20 #include <linux/export.h>
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
get_clock(void * data)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
get_data(void * data)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
set_clock(void * data,int state_high)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
set_data(void * data,int state_high)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 */
psb_intel_i2c_create(struct drm_device * dev,const u32 reg,const char * name)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 */
psb_intel_i2c_destroy(struct psb_intel_i2c_chan * chan)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 }
170