1 /*
2  * Copyright 2012 Red Hat Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the
6  * "Software"), to deal in the Software without restriction, including
7  * without limitation the rights to use, copy, modify, merge, publish,
8  * distribute, sub license, and/or sell copies of the Software, and to
9  * permit persons to whom the Software is furnished to do so, subject to
10  * the following conditions:
11  *
12  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
13  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
14  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
15  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
16  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
17  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
18  * USE OR OTHER DEALINGS IN THE SOFTWARE.
19  *
20  * The above copyright notice and this permission notice (including the
21  * next paragraph) shall be included in all copies or substantial portions
22  * of the Software.
23  *
24  */
25 /*
26  * Authors: Dave Airlie <airlied@redhat.com>
27  */
28 #include <linux/export.h>
29 #include <linux/i2c.h>
30 #include <linux/i2c-algo-bit.h>
31 #include <drm/drmP.h>
32 
33 #include "mgag200_drv.h"
34 
35 static int mga_i2c_read_gpio(struct mga_device *mdev)
36 {
37 	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
38 	return RREG8(DAC_DATA);
39 }
40 
41 static void mga_i2c_set_gpio(struct mga_device *mdev, int mask, int val)
42 {
43 	int tmp;
44 
45 	WREG8(DAC_INDEX, MGA1064_GEN_IO_CTL);
46 	tmp = (RREG8(DAC_DATA) & mask) | val;
47 	WREG_DAC(MGA1064_GEN_IO_CTL, tmp);
48 	WREG_DAC(MGA1064_GEN_IO_DATA, 0);
49 }
50 
51 static inline void mga_i2c_set(struct mga_device *mdev, int mask, int state)
52 {
53 	if (state)
54 		state = 0;
55 	else
56 		state = mask;
57 	mga_i2c_set_gpio(mdev, ~mask, state);
58 }
59 
60 static void mga_gpio_setsda(void *data, int state)
61 {
62 	struct mga_i2c_chan *i2c = data;
63 	struct mga_device *mdev = i2c->dev->dev_private;
64 	mga_i2c_set(mdev, i2c->data, state);
65 }
66 
67 static void mga_gpio_setscl(void *data, int state)
68 {
69 	struct mga_i2c_chan *i2c = data;
70 	struct mga_device *mdev = i2c->dev->dev_private;
71 	mga_i2c_set(mdev, i2c->clock, state);
72 }
73 
74 static int mga_gpio_getsda(void *data)
75 {
76 	struct mga_i2c_chan *i2c = data;
77 	struct mga_device *mdev = i2c->dev->dev_private;
78 	return (mga_i2c_read_gpio(mdev) & i2c->data) ? 1 : 0;
79 }
80 
81 static int mga_gpio_getscl(void *data)
82 {
83 	struct mga_i2c_chan *i2c = data;
84 	struct mga_device *mdev = i2c->dev->dev_private;
85 	return (mga_i2c_read_gpio(mdev) & i2c->clock) ? 1 : 0;
86 }
87 
88 struct mga_i2c_chan *mgag200_i2c_create(struct drm_device *dev)
89 {
90 	struct mga_device *mdev = dev->dev_private;
91 	struct mga_i2c_chan *i2c;
92 	int ret;
93 	int data, clock;
94 
95 	WREG_DAC(MGA1064_GEN_IO_CTL2, 1);
96 	WREG_DAC(MGA1064_GEN_IO_DATA, 0xff);
97 	WREG_DAC(MGA1064_GEN_IO_CTL, 0);
98 
99 	switch (mdev->type) {
100 	case G200_SE_A:
101 	case G200_SE_B:
102 	case G200_EV:
103 	case G200_WB:
104 		data = 1;
105 		clock = 2;
106 		break;
107 	case G200_EH:
108 	case G200_ER:
109 		data = 2;
110 		clock = 1;
111 		break;
112 	default:
113 		data = 2;
114 		clock = 8;
115 		break;
116 	}
117 
118 	i2c = kzalloc(sizeof(struct mga_i2c_chan), GFP_KERNEL);
119 	if (!i2c)
120 		return NULL;
121 
122 	i2c->data = data;
123 	i2c->clock = clock;
124 	i2c->adapter.owner = THIS_MODULE;
125 	i2c->adapter.class = I2C_CLASS_DDC;
126 	i2c->adapter.dev.parent = &dev->pdev->dev;
127 	i2c->dev = dev;
128 	i2c_set_adapdata(&i2c->adapter, i2c);
129 	snprintf(i2c->adapter.name, sizeof(i2c->adapter.name), "mga i2c");
130 
131 	i2c->adapter.algo_data = &i2c->bit;
132 
133 	i2c->bit.udelay = 10;
134 	i2c->bit.timeout = 2;
135 	i2c->bit.data = i2c;
136 	i2c->bit.setsda		= mga_gpio_setsda;
137 	i2c->bit.setscl		= mga_gpio_setscl;
138 	i2c->bit.getsda		= mga_gpio_getsda;
139 	i2c->bit.getscl		= mga_gpio_getscl;
140 
141 	ret = i2c_bit_add_bus(&i2c->adapter);
142 	if (ret) {
143 		kfree(i2c);
144 		i2c = NULL;
145 	}
146 	return i2c;
147 }
148 
149 void mgag200_i2c_destroy(struct mga_i2c_chan *i2c)
150 {
151 	if (!i2c)
152 		return;
153 	i2c_del_adapter(&i2c->adapter);
154 	kfree(i2c);
155 }
156 
157