xref: /openbmc/linux/drivers/gpu/drm/ast/ast_i2c.c (revision 9a29f5fc)
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 <drm/drm_managed.h>
25 #include <drm/drm_print.h>
26 
27 #include "ast_drv.h"
28 
29 static void ast_i2c_setsda(void *i2c_priv, int data)
30 {
31 	struct ast_i2c_chan *i2c = i2c_priv;
32 	struct ast_private *ast = to_ast_private(i2c->dev);
33 	int i;
34 	u8 ujcrb7, jtemp;
35 
36 	for (i = 0; i < 0x10000; i++) {
37 		ujcrb7 = ((data & 0x01) ? 0 : 1) << 2;
38 		ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf1, ujcrb7);
39 		jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x04);
40 		if (ujcrb7 == jtemp)
41 			break;
42 	}
43 }
44 
45 static void ast_i2c_setscl(void *i2c_priv, int clock)
46 {
47 	struct ast_i2c_chan *i2c = i2c_priv;
48 	struct ast_private *ast = to_ast_private(i2c->dev);
49 	int i;
50 	u8 ujcrb7, jtemp;
51 
52 	for (i = 0; i < 0x10000; i++) {
53 		ujcrb7 = ((clock & 0x01) ? 0 : 1);
54 		ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0xf4, ujcrb7);
55 		jtemp = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x01);
56 		if (ujcrb7 == jtemp)
57 			break;
58 	}
59 }
60 
61 static int ast_i2c_getsda(void *i2c_priv)
62 {
63 	struct ast_i2c_chan *i2c = i2c_priv;
64 	struct ast_private *ast = to_ast_private(i2c->dev);
65 	uint32_t val, val2, count, pass;
66 
67 	count = 0;
68 	pass = 0;
69 	val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
70 	do {
71 		val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
72 		if (val == val2) {
73 			pass++;
74 		} else {
75 			pass = 0;
76 			val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x20) >> 5) & 0x01;
77 		}
78 	} while ((pass < 5) && (count++ < 0x10000));
79 
80 	return val & 1 ? 1 : 0;
81 }
82 
83 static int ast_i2c_getscl(void *i2c_priv)
84 {
85 	struct ast_i2c_chan *i2c = i2c_priv;
86 	struct ast_private *ast = to_ast_private(i2c->dev);
87 	uint32_t val, val2, count, pass;
88 
89 	count = 0;
90 	pass = 0;
91 	val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
92 	do {
93 		val2 = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
94 		if (val == val2) {
95 			pass++;
96 		} else {
97 			pass = 0;
98 			val = (ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xb7, 0x10) >> 4) & 0x01;
99 		}
100 	} while ((pass < 5) && (count++ < 0x10000));
101 
102 	return val & 1 ? 1 : 0;
103 }
104 
105 static void ast_i2c_release(struct drm_device *dev, void *res)
106 {
107 	struct ast_i2c_chan *i2c = res;
108 
109 	i2c_del_adapter(&i2c->adapter);
110 	kfree(i2c);
111 }
112 
113 struct ast_i2c_chan *ast_i2c_create(struct drm_device *dev)
114 {
115 	struct ast_i2c_chan *i2c;
116 	int ret;
117 
118 	i2c = kzalloc(sizeof(struct ast_i2c_chan), GFP_KERNEL);
119 	if (!i2c)
120 		return NULL;
121 
122 	i2c->adapter.owner = THIS_MODULE;
123 	i2c->adapter.class = I2C_CLASS_DDC;
124 	i2c->adapter.dev.parent = dev->dev;
125 	i2c->dev = dev;
126 	i2c_set_adapdata(&i2c->adapter, i2c);
127 	snprintf(i2c->adapter.name, sizeof(i2c->adapter.name),
128 		 "AST i2c bit bus");
129 	i2c->adapter.algo_data = &i2c->bit;
130 
131 	i2c->bit.udelay = 20;
132 	i2c->bit.timeout = 2;
133 	i2c->bit.data = i2c;
134 	i2c->bit.setsda = ast_i2c_setsda;
135 	i2c->bit.setscl = ast_i2c_setscl;
136 	i2c->bit.getsda = ast_i2c_getsda;
137 	i2c->bit.getscl = ast_i2c_getscl;
138 	ret = i2c_bit_add_bus(&i2c->adapter);
139 	if (ret) {
140 		drm_err(dev, "Failed to register bit i2c\n");
141 		goto out_kfree;
142 	}
143 
144 	ret = drmm_add_action_or_reset(dev, ast_i2c_release, i2c);
145 	if (ret)
146 		return NULL;
147 	return i2c;
148 
149 out_kfree:
150 	kfree(i2c);
151 	return NULL;
152 }
153