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3192 | Serge | 1 | /* |
2 | * Copyright © 2009 Keith Packard |
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3 | * |
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4 | * Permission to use, copy, modify, distribute, and sell this software and its |
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5 | * documentation for any purpose is hereby granted without fee, provided that |
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6 | * the above copyright notice appear in all copies and that both that copyright |
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7 | * notice and this permission notice appear in supporting documentation, and |
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8 | * that the name of the copyright holders not be used in advertising or |
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9 | * publicity pertaining to distribution of the software without specific, |
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10 | * written prior permission. The copyright holders make no representations |
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11 | * about the suitability of this software for any purpose. It is provided "as |
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12 | * is" without express or implied warranty. |
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13 | * |
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14 | * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
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15 | * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO |
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16 | * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR |
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17 | * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, |
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18 | * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER |
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19 | * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE |
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20 | * OF THIS SOFTWARE. |
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21 | */ |
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22 | |||
23 | #include |
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24 | #include |
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25 | //#include |
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26 | //#include |
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27 | #include |
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28 | #include |
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29 | #include |
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30 | #include |
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31 | #include |
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32 | |||
33 | /** |
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34 | * DOC: dp helpers |
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35 | * |
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36 | * These functions contain some common logic and helpers at various abstraction |
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37 | * levels to deal with Display Port sink devices and related things like DP aux |
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38 | * channel transfers, EDID reading over DP aux channels, decoding certain DPCD |
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39 | * blocks, ... |
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40 | */ |
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41 | |||
42 | /* Run a single AUX_CH I2C transaction, writing/reading data as necessary */ |
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43 | static int |
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44 | i2c_algo_dp_aux_transaction(struct i2c_adapter *adapter, int mode, |
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45 | uint8_t write_byte, uint8_t *read_byte) |
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46 | { |
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47 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
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48 | int ret; |
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49 | |||
50 | ret = (*algo_data->aux_ch)(adapter, mode, |
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51 | write_byte, read_byte); |
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52 | return ret; |
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53 | } |
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54 | |||
55 | /* |
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56 | * I2C over AUX CH |
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57 | */ |
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58 | |||
59 | /* |
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60 | * Send the address. If the I2C link is running, this 'restarts' |
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61 | * the connection with the new address, this is used for doing |
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62 | * a write followed by a read (as needed for DDC) |
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63 | */ |
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64 | static int |
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65 | i2c_algo_dp_aux_address(struct i2c_adapter *adapter, u16 address, bool reading) |
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66 | { |
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67 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
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68 | int mode = MODE_I2C_START; |
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69 | int ret; |
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70 | |||
71 | if (reading) |
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72 | mode |= MODE_I2C_READ; |
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73 | else |
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74 | mode |= MODE_I2C_WRITE; |
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75 | algo_data->address = address; |
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76 | algo_data->running = true; |
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77 | ret = i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL); |
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78 | return ret; |
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79 | } |
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80 | |||
81 | /* |
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82 | * Stop the I2C transaction. This closes out the link, sending |
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83 | * a bare address packet with the MOT bit turned off |
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84 | */ |
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85 | static void |
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86 | i2c_algo_dp_aux_stop(struct i2c_adapter *adapter, bool reading) |
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87 | { |
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88 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
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89 | int mode = MODE_I2C_STOP; |
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90 | |||
91 | if (reading) |
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92 | mode |= MODE_I2C_READ; |
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93 | else |
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94 | mode |= MODE_I2C_WRITE; |
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95 | if (algo_data->running) { |
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96 | (void) i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL); |
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97 | algo_data->running = false; |
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98 | } |
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99 | } |
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100 | |||
101 | /* |
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102 | * Write a single byte to the current I2C address, the |
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103 | * the I2C link must be running or this returns -EIO |
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104 | */ |
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105 | static int |
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106 | i2c_algo_dp_aux_put_byte(struct i2c_adapter *adapter, u8 byte) |
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107 | { |
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108 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
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109 | int ret; |
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110 | |||
111 | if (!algo_data->running) |
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112 | return -EIO; |
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113 | |||
114 | ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_WRITE, byte, NULL); |
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115 | return ret; |
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116 | } |
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117 | |||
118 | /* |
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119 | * Read a single byte from the current I2C address, the |
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120 | * I2C link must be running or this returns -EIO |
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121 | */ |
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122 | static int |
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123 | i2c_algo_dp_aux_get_byte(struct i2c_adapter *adapter, u8 *byte_ret) |
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124 | { |
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125 | struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data; |
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126 | int ret; |
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127 | |||
128 | if (!algo_data->running) |
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129 | return -EIO; |
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130 | |||
131 | ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_READ, 0, byte_ret); |
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132 | return ret; |
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133 | } |
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134 | |||
135 | static int |
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136 | i2c_algo_dp_aux_xfer(struct i2c_adapter *adapter, |
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137 | struct i2c_msg *msgs, |
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138 | int num) |
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139 | { |
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140 | int ret = 0; |
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141 | bool reading = false; |
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142 | int m; |
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143 | int b; |
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144 | |||
145 | for (m = 0; m < num; m++) { |
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146 | u16 len = msgs[m].len; |
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147 | u8 *buf = msgs[m].buf; |
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148 | reading = (msgs[m].flags & I2C_M_RD) != 0; |
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149 | ret = i2c_algo_dp_aux_address(adapter, msgs[m].addr, reading); |
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150 | if (ret < 0) |
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151 | break; |
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152 | if (reading) { |
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153 | for (b = 0; b < len; b++) { |
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154 | ret = i2c_algo_dp_aux_get_byte(adapter, &buf[b]); |
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155 | if (ret < 0) |
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156 | break; |
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157 | } |
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158 | } else { |
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159 | for (b = 0; b < len; b++) { |
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160 | ret = i2c_algo_dp_aux_put_byte(adapter, buf[b]); |
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161 | if (ret < 0) |
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162 | break; |
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163 | } |
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164 | } |
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165 | if (ret < 0) |
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166 | break; |
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167 | } |
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168 | if (ret >= 0) |
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169 | ret = num; |
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170 | i2c_algo_dp_aux_stop(adapter, reading); |
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171 | DRM_DEBUG_KMS("dp_aux_xfer return %d\n", ret); |
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172 | return ret; |
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173 | } |
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174 | |||
175 | static u32 |
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176 | i2c_algo_dp_aux_functionality(struct i2c_adapter *adapter) |
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177 | { |
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178 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
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179 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
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180 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | |
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181 | I2C_FUNC_10BIT_ADDR; |
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182 | } |
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183 | |||
184 | static const struct i2c_algorithm i2c_dp_aux_algo = { |
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185 | .master_xfer = i2c_algo_dp_aux_xfer, |
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186 | .functionality = i2c_algo_dp_aux_functionality, |
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187 | }; |
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188 | |||
189 | static void |
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190 | i2c_dp_aux_reset_bus(struct i2c_adapter *adapter) |
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191 | { |
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192 | (void) i2c_algo_dp_aux_address(adapter, 0, false); |
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193 | (void) i2c_algo_dp_aux_stop(adapter, false); |
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194 | } |
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195 | |||
196 | static int |
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197 | i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter) |
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198 | { |
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199 | adapter->algo = &i2c_dp_aux_algo; |
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200 | adapter->retries = 3; |
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201 | i2c_dp_aux_reset_bus(adapter); |
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202 | return 0; |
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203 | } |
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204 | |||
205 | /** |
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206 | * i2c_dp_aux_add_bus() - register an i2c adapter using the aux ch helper |
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207 | * @adapter: i2c adapter to register |
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208 | * |
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209 | * This registers an i2c adapater that uses dp aux channel as it's underlaying |
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210 | * transport. The driver needs to fill out the &i2c_algo_dp_aux_data structure |
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211 | * and store it in the algo_data member of the @adapter argument. This will be |
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212 | * used by the i2c over dp aux algorithm to drive the hardware. |
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213 | * |
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214 | * RETURNS: |
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215 | * 0 on success, -ERRNO on failure. |
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216 | */ |
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217 | int |
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218 | i2c_dp_aux_add_bus(struct i2c_adapter *adapter) |
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219 | { |
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220 | int error; |
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221 | |||
222 | error = i2c_dp_aux_prepare_bus(adapter); |
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223 | if (error) |
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224 | return error; |
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225 | error = i2c_add_adapter(adapter); |
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226 | return error; |
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227 | } |
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228 | EXPORT_SYMBOL(i2c_dp_aux_add_bus); |
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229 | |||
230 | /* Helpers for DP link training */ |
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4560 | Serge | 231 | static u8 dp_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r) |
3192 | Serge | 232 | { |
233 | return link_status[r - DP_LANE0_1_STATUS]; |
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234 | } |
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235 | |||
4560 | Serge | 236 | static u8 dp_get_lane_status(const u8 link_status[DP_LINK_STATUS_SIZE], |
3192 | Serge | 237 | int lane) |
238 | { |
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239 | int i = DP_LANE0_1_STATUS + (lane >> 1); |
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240 | int s = (lane & 1) * 4; |
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241 | u8 l = dp_link_status(link_status, i); |
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242 | return (l >> s) & 0xf; |
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243 | } |
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244 | |||
4560 | Serge | 245 | bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE], |
3192 | Serge | 246 | int lane_count) |
247 | { |
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248 | u8 lane_align; |
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249 | u8 lane_status; |
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250 | int lane; |
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251 | |||
252 | lane_align = dp_link_status(link_status, |
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253 | DP_LANE_ALIGN_STATUS_UPDATED); |
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254 | if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0) |
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255 | return false; |
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256 | for (lane = 0; lane < lane_count; lane++) { |
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257 | lane_status = dp_get_lane_status(link_status, lane); |
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258 | if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS) |
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259 | return false; |
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260 | } |
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261 | return true; |
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262 | } |
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263 | EXPORT_SYMBOL(drm_dp_channel_eq_ok); |
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264 | |||
4560 | Serge | 265 | bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE], |
3192 | Serge | 266 | int lane_count) |
267 | { |
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268 | int lane; |
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269 | u8 lane_status; |
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270 | |||
271 | for (lane = 0; lane < lane_count; lane++) { |
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272 | lane_status = dp_get_lane_status(link_status, lane); |
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273 | if ((lane_status & DP_LANE_CR_DONE) == 0) |
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274 | return false; |
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275 | } |
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276 | return true; |
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277 | } |
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278 | EXPORT_SYMBOL(drm_dp_clock_recovery_ok); |
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279 | |||
4560 | Serge | 280 | u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE], |
3192 | Serge | 281 | int lane) |
282 | { |
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283 | int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); |
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284 | int s = ((lane & 1) ? |
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285 | DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT : |
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286 | DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT); |
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287 | u8 l = dp_link_status(link_status, i); |
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288 | |||
289 | return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT; |
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290 | } |
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291 | EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage); |
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292 | |||
4560 | Serge | 293 | u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE], |
3192 | Serge | 294 | int lane) |
295 | { |
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296 | int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); |
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297 | int s = ((lane & 1) ? |
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298 | DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT : |
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299 | DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT); |
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300 | u8 l = dp_link_status(link_status, i); |
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301 | |||
302 | return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT; |
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303 | } |
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304 | EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); |
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305 | |||
4560 | Serge | 306 | void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { |
3192 | Serge | 307 | if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) |
308 | udelay(100); |
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309 | else |
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310 | mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); |
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311 | } |
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312 | EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay); |
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313 | |||
4560 | Serge | 314 | void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) { |
3192 | Serge | 315 | if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0) |
316 | udelay(400); |
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317 | else |
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318 | mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4); |
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319 | } |
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320 | EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay); |
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321 | |||
322 | u8 drm_dp_link_rate_to_bw_code(int link_rate) |
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323 | { |
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324 | switch (link_rate) { |
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325 | case 162000: |
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326 | default: |
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327 | return DP_LINK_BW_1_62; |
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328 | case 270000: |
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329 | return DP_LINK_BW_2_7; |
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330 | case 540000: |
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331 | return DP_LINK_BW_5_4; |
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332 | } |
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333 | } |
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334 | EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code); |
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335 | |||
336 | int drm_dp_bw_code_to_link_rate(u8 link_bw) |
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337 | { |
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338 | switch (link_bw) { |
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339 | case DP_LINK_BW_1_62: |
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340 | default: |
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341 | return 162000; |
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342 | case DP_LINK_BW_2_7: |
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343 | return 270000; |
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344 | case DP_LINK_BW_5_4: |
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345 | return 540000; |
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346 | } |
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347 | } |
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348 | EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate);><>><>>>>>>>>>> |