1// SPDX-License-Identifier: MIT
2/*
3 * Permission is hereby granted, free of charge, to any person obtaining a
4 * copy of this software and associated documentation files (the
5 * "Software"), to deal in the Software without restriction, including
6 * without limitation the rights to use, copy, modify, merge, publish,
7 * distribute, sub license, and/or sell copies of the Software, and to
8 * permit persons to whom the Software is furnished to do so, subject to
9 * the following conditions:
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
12 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
13 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
14 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
16 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
17 * USE OR OTHER DEALINGS IN THE SOFTWARE.
18 *
19 * The above copyright notice and this permission notice (including the
20 * next paragraph) shall be included in all copies or substantial portions
21 * of the Software.
22 */
23
24#include <linux/i2c-algo-bit.h>
25#include <linux/i2c.h>
26
27#include <drm/drm_managed.h>
28#include <drm/drm_print.h>
29
30#include "ast_ddc.h"
31#include "ast_drv.h"
32
33struct ast_ddc {
34 struct ast_device *ast;
35
36 struct i2c_algo_bit_data bit;
37 struct i2c_adapter adapter;
38};
39
40static void ast_ddc_algo_bit_data_setsda(void *data, int state)
41{
42 struct ast_ddc *ddc = data;
43 struct ast_device *ast = ddc->ast;
44 int i;
45 u8 ujcrb7, jtemp;
46
47 for (i = 0; i < 0x10000; i++) {
48 ujcrb7 = ((state & 0x01) ? 0 : 1) << 2;
49 ast_set_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0xf1, val: ujcrb7);
50 jtemp = ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x04);
51 if (ujcrb7 == jtemp)
52 break;
53 }
54}
55
56static void ast_ddc_algo_bit_data_setscl(void *data, int state)
57{
58 struct ast_ddc *ddc = data;
59 struct ast_device *ast = ddc->ast;
60 int i;
61 u8 ujcrb7, jtemp;
62
63 for (i = 0; i < 0x10000; i++) {
64 ujcrb7 = ((state & 0x01) ? 0 : 1);
65 ast_set_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0xf4, val: ujcrb7);
66 jtemp = ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x01);
67 if (ujcrb7 == jtemp)
68 break;
69 }
70}
71
72static int ast_ddc_algo_bit_data_pre_xfer(struct i2c_adapter *adapter)
73{
74 struct ast_ddc *ddc = i2c_get_adapdata(adap: adapter);
75 struct ast_device *ast = ddc->ast;
76
77 /*
78 * Protect access to I/O registers from concurrent modesetting
79 * by acquiring the I/O-register lock.
80 */
81 mutex_lock(&ast->modeset_lock);
82
83 return 0;
84}
85
86static void ast_ddc_algo_bit_data_post_xfer(struct i2c_adapter *adapter)
87{
88 struct ast_ddc *ddc = i2c_get_adapdata(adap: adapter);
89 struct ast_device *ast = ddc->ast;
90
91 mutex_unlock(lock: &ast->modeset_lock);
92}
93
94static int ast_ddc_algo_bit_data_getsda(void *data)
95{
96 struct ast_ddc *ddc = data;
97 struct ast_device *ast = ddc->ast;
98 uint32_t val, val2, count, pass;
99
100 count = 0;
101 pass = 0;
102 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x20) >> 5) & 0x01;
103 do {
104 val2 = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x20) >> 5) & 0x01;
105 if (val == val2) {
106 pass++;
107 } else {
108 pass = 0;
109 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x20) >> 5) & 0x01;
110 }
111 } while ((pass < 5) && (count++ < 0x10000));
112
113 return val & 1 ? 1 : 0;
114}
115
116static int ast_ddc_algo_bit_data_getscl(void *data)
117{
118 struct ast_ddc *ddc = data;
119 struct ast_device *ast = ddc->ast;
120 uint32_t val, val2, count, pass;
121
122 count = 0;
123 pass = 0;
124 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x10) >> 4) & 0x01;
125 do {
126 val2 = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x10) >> 4) & 0x01;
127 if (val == val2) {
128 pass++;
129 } else {
130 pass = 0;
131 val = (ast_get_index_reg_mask(ast, AST_IO_VGACRI, index: 0xb7, preserve_mask: 0x10) >> 4) & 0x01;
132 }
133 } while ((pass < 5) && (count++ < 0x10000));
134
135 return val & 1 ? 1 : 0;
136}
137
138static void ast_ddc_release(struct drm_device *dev, void *res)
139{
140 struct ast_ddc *ddc = res;
141
142 i2c_del_adapter(adap: &ddc->adapter);
143}
144
145struct i2c_adapter *ast_ddc_create(struct ast_device *ast)
146{
147 struct drm_device *dev = &ast->base;
148 struct ast_ddc *ddc;
149 struct i2c_adapter *adapter;
150 struct i2c_algo_bit_data *bit;
151 int ret;
152
153 ddc = drmm_kzalloc(dev, size: sizeof(*ddc), GFP_KERNEL);
154 if (!ddc)
155 return ERR_PTR(error: -ENOMEM);
156 ddc->ast = ast;
157
158 bit = &ddc->bit;
159 bit->data = ddc;
160 bit->setsda = ast_ddc_algo_bit_data_setsda;
161 bit->setscl = ast_ddc_algo_bit_data_setscl;
162 bit->getsda = ast_ddc_algo_bit_data_getsda;
163 bit->getscl = ast_ddc_algo_bit_data_getscl;
164 bit->pre_xfer = ast_ddc_algo_bit_data_pre_xfer;
165 bit->post_xfer = ast_ddc_algo_bit_data_post_xfer;
166 bit->udelay = 20;
167 bit->timeout = usecs_to_jiffies(u: 2200);
168
169 adapter = &ddc->adapter;
170 adapter->owner = THIS_MODULE;
171 adapter->algo_data = bit;
172 adapter->dev.parent = dev->dev;
173 snprintf(buf: adapter->name, size: sizeof(adapter->name), fmt: "AST DDC bus");
174 i2c_set_adapdata(adap: adapter, data: ddc);
175
176 ret = i2c_bit_add_bus(adapter);
177 if (ret) {
178 drm_err(dev, "Failed to register bit i2c\n");
179 return ERR_PTR(error: ret);
180 }
181
182 ret = drmm_add_action_or_reset(dev, ast_ddc_release, ddc);
183 if (ret)
184 return ERR_PTR(error: ret);
185
186 return &ddc->adapter;
187}
188

source code of linux/drivers/gpu/drm/ast/ast_ddc.c