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Rev | Author | Line No. | Line |
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1125 | serge | 1 | /* ------------------------------------------------------------------------- |
2 | * i2c-algo-bit.c i2c driver algorithms for bit-shift adapters |
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3 | * ------------------------------------------------------------------------- |
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4 | * Copyright (C) 1995-2000 Simon G. Vogl |
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5 | |||
6 | This program is free software; you can redistribute it and/or modify |
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7 | it under the terms of the GNU General Public License as published by |
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8 | the Free Software Foundation; either version 2 of the License, or |
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9 | (at your option) any later version. |
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10 | |||
11 | This program is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | GNU General Public License for more details. |
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15 | |||
16 | You should have received a copy of the GNU General Public License |
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17 | along with this program; if not, write to the Free Software |
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3031 | serge | 18 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
19 | MA 02110-1301 USA. |
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1125 | serge | 20 | * ------------------------------------------------------------------------- */ |
21 | |||
22 | /* With some changes from Frodo Looijaard |
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23 |
|
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24 | |||
25 | #include |
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26 | #include |
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1403 | serge | 27 | #include |
3031 | serge | 28 | #include |
1125 | serge | 29 | #include |
4104 | Serge | 30 | #include |
1125 | serge | 31 | #include |
32 | #include |
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33 | #include |
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34 | |||
3031 | serge | 35 | #define I2C_FUNC_NOSTART 0x00000010 /* I2C_M_NOSTART */ |
1125 | serge | 36 | |
37 | /* ----- global defines ----------------------------------------------- */ |
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38 | |||
39 | #ifdef DEBUG |
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40 | #define bit_dbg(level, dev, format, args...) \ |
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41 | do { \ |
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42 | if (i2c_debug >= level) \ |
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43 | dev_dbg(dev, format, ##args); \ |
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44 | } while (0) |
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45 | #else |
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46 | #define bit_dbg(level, dev, format, args...) \ |
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4104 | Serge | 47 | do {} while (0) |
1125 | serge | 48 | #endif /* DEBUG */ |
49 | |||
50 | /* ----- global variables --------------------------------------------- */ |
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51 | |||
3031 | serge | 52 | static int bit_test = 0; /* see if the line-setting functions work */ |
1125 | serge | 53 | |
3031 | serge | 54 | #ifdef DEBUG |
55 | static int i2c_debug = 1; |
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56 | module_param(i2c_debug, int, S_IRUGO | S_IWUSR); |
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57 | MODULE_PARM_DESC(i2c_debug, |
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58 | "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose"); |
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59 | #endif |
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1125 | serge | 60 | |
61 | /* --- setting states on the bus with the right timing: --------------- */ |
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62 | |||
63 | #define setsda(adap, val) adap->setsda(adap->data, val) |
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64 | #define setscl(adap, val) adap->setscl(adap->data, val) |
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65 | #define getsda(adap) adap->getsda(adap->data) |
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66 | #define getscl(adap) adap->getscl(adap->data) |
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67 | |||
68 | static inline void sdalo(struct i2c_algo_bit_data *adap) |
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69 | { |
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70 | setsda(adap, 0); |
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71 | udelay((adap->udelay + 1) / 2); |
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72 | } |
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73 | |||
74 | static inline void sdahi(struct i2c_algo_bit_data *adap) |
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75 | { |
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76 | setsda(adap, 1); |
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77 | udelay((adap->udelay + 1) / 2); |
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78 | } |
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79 | |||
80 | static inline void scllo(struct i2c_algo_bit_data *adap) |
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81 | { |
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82 | setscl(adap, 0); |
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83 | udelay(adap->udelay / 2); |
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84 | } |
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85 | |||
86 | /* |
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87 | * Raise scl line, and do checking for delays. This is necessary for slower |
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88 | * devices. |
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89 | */ |
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90 | static int sclhi(struct i2c_algo_bit_data *adap) |
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91 | { |
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92 | unsigned long start; |
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93 | |||
94 | setscl(adap, 1); |
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95 | |||
96 | /* Not all adapters have scl sense line... */ |
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97 | if (!adap->getscl) |
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98 | goto done; |
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99 | |||
3031 | serge | 100 | start = GetTimerTicks(); |
1125 | serge | 101 | while (!getscl(adap)) { |
102 | /* This hw knows how to read the clock line, so we wait |
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103 | * until it actually gets high. This is safer as some |
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104 | * chips may hold it low ("clock stretching") while they |
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105 | * are processing data internally. |
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106 | */ |
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3031 | serge | 107 | if (time_after(GetTimerTicks(), start + adap->timeout)) { |
108 | /* Test one last time, as we may have been preempted |
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109 | * between last check and timeout test. |
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110 | */ |
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111 | if (getscl(adap)) |
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112 | break; |
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113 | return -ETIMEDOUT; |
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114 | } |
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3120 | serge | 115 | asm volatile("rep; nop" ::: "memory"); |
3031 | serge | 116 | } |
1125 | serge | 117 | done: |
118 | udelay(adap->udelay); |
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119 | return 0; |
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120 | } |
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121 | |||
122 | |||
123 | /* --- other auxiliary functions -------------------------------------- */ |
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124 | static void i2c_start(struct i2c_algo_bit_data *adap) |
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125 | { |
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126 | /* assert: scl, sda are high */ |
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127 | setsda(adap, 0); |
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128 | udelay(adap->udelay); |
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129 | scllo(adap); |
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130 | } |
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131 | |||
132 | static void i2c_repstart(struct i2c_algo_bit_data *adap) |
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133 | { |
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134 | /* assert: scl is low */ |
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135 | sdahi(adap); |
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136 | sclhi(adap); |
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137 | setsda(adap, 0); |
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138 | udelay(adap->udelay); |
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139 | scllo(adap); |
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140 | } |
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141 | |||
142 | |||
143 | static void i2c_stop(struct i2c_algo_bit_data *adap) |
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144 | { |
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145 | /* assert: scl is low */ |
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146 | sdalo(adap); |
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147 | sclhi(adap); |
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148 | setsda(adap, 1); |
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149 | udelay(adap->udelay); |
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150 | } |
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151 | |||
152 | |||
153 | |||
154 | /* send a byte without start cond., look for arbitration, |
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155 | check ackn. from slave */ |
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156 | /* returns: |
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157 | * 1 if the device acknowledged |
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158 | * 0 if the device did not ack |
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159 | * -ETIMEDOUT if an error occurred (while raising the scl line) |
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160 | */ |
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161 | static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) |
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162 | { |
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163 | int i; |
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164 | int sb; |
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165 | int ack; |
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166 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
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167 | |||
168 | /* assert: scl is low */ |
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169 | for (i = 7; i >= 0; i--) { |
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170 | sb = (c >> i) & 1; |
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171 | setsda(adap, sb); |
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172 | udelay((adap->udelay + 1) / 2); |
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173 | if (sclhi(adap) < 0) { /* timed out */ |
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1963 | serge | 174 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
175 | "timeout at bit #%d\n", (int)c, i); |
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1125 | serge | 176 | return -ETIMEDOUT; |
177 | } |
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178 | /* FIXME do arbitration here: |
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179 | * if (sb && !getsda(adap)) -> ouch! Get out of here. |
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180 | * |
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181 | * Report a unique code, so higher level code can retry |
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182 | * the whole (combined) message and *NOT* issue STOP. |
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183 | */ |
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184 | scllo(adap); |
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185 | } |
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186 | sdahi(adap); |
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187 | if (sclhi(adap) < 0) { /* timeout */ |
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1963 | serge | 188 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
189 | "timeout at ack\n", (int)c); |
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1125 | serge | 190 | return -ETIMEDOUT; |
191 | } |
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192 | |||
193 | /* read ack: SDA should be pulled down by slave, or it may |
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194 | * NAK (usually to report problems with the data we wrote). |
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195 | */ |
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196 | ack = !getsda(adap); /* ack: sda is pulled low -> success */ |
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1963 | serge | 197 | bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, |
198 | ack ? "A" : "NA"); |
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1125 | serge | 199 | |
200 | scllo(adap); |
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201 | return ack; |
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202 | /* assert: scl is low (sda undef) */ |
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203 | } |
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204 | |||
205 | |||
206 | static int i2c_inb(struct i2c_adapter *i2c_adap) |
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207 | { |
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208 | /* read byte via i2c port, without start/stop sequence */ |
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209 | /* acknowledge is sent in i2c_read. */ |
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210 | int i; |
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211 | unsigned char indata = 0; |
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212 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
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213 | |||
214 | /* assert: scl is low */ |
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215 | sdahi(adap); |
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216 | for (i = 0; i < 8; i++) { |
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217 | if (sclhi(adap) < 0) { /* timeout */ |
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218 | bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit " |
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219 | "#%d\n", 7 - i); |
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220 | return -ETIMEDOUT; |
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221 | } |
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222 | indata *= 2; |
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223 | if (getsda(adap)) |
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224 | indata |= 0x01; |
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225 | setscl(adap, 0); |
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226 | udelay(i == 7 ? adap->udelay / 2 : adap->udelay); |
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227 | } |
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228 | /* assert: scl is low */ |
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229 | return indata; |
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230 | } |
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231 | |||
232 | /* |
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233 | * Sanity check for the adapter hardware - check the reaction of |
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234 | * the bus lines only if it seems to be idle. |
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235 | */ |
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1963 | serge | 236 | static int test_bus(struct i2c_adapter *i2c_adap) |
1125 | serge | 237 | { |
1963 | serge | 238 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
239 | const char *name = i2c_adap->name; |
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240 | int scl, sda, ret; |
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1125 | serge | 241 | |
1963 | serge | 242 | if (adap->pre_xfer) { |
243 | ret = adap->pre_xfer(i2c_adap); |
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244 | if (ret < 0) |
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245 | return -ENODEV; |
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246 | } |
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247 | |||
1125 | serge | 248 | if (adap->getscl == NULL) |
3031 | serge | 249 | dbgprintf("%s: Testing SDA only, SCL is not readable\n", name); |
1125 | serge | 250 | |
251 | sda = getsda(adap); |
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252 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); |
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253 | if (!scl || !sda) { |
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3031 | serge | 254 | printk(KERN_WARNING |
255 | "%s: bus seems to be busy (scl=%d, sda=%d)\n", |
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256 | name, scl, sda); |
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1125 | serge | 257 | goto bailout; |
258 | } |
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259 | |||
260 | sdalo(adap); |
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261 | sda = getsda(adap); |
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262 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); |
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263 | if (sda) { |
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264 | printk(KERN_WARNING "%s: SDA stuck high!\n", name); |
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265 | goto bailout; |
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266 | } |
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267 | if (!scl) { |
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268 | printk(KERN_WARNING "%s: SCL unexpected low " |
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269 | "while pulling SDA low!\n", name); |
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270 | goto bailout; |
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271 | } |
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272 | |||
273 | sdahi(adap); |
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274 | sda = getsda(adap); |
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275 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); |
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276 | if (!sda) { |
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277 | printk(KERN_WARNING "%s: SDA stuck low!\n", name); |
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278 | goto bailout; |
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279 | } |
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280 | if (!scl) { |
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281 | printk(KERN_WARNING "%s: SCL unexpected low " |
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282 | "while pulling SDA high!\n", name); |
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283 | goto bailout; |
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284 | } |
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285 | |||
286 | scllo(adap); |
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287 | sda = getsda(adap); |
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288 | scl = (adap->getscl == NULL) ? 0 : getscl(adap); |
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289 | if (scl) { |
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290 | printk(KERN_WARNING "%s: SCL stuck high!\n", name); |
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291 | goto bailout; |
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292 | } |
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293 | if (!sda) { |
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294 | printk(KERN_WARNING "%s: SDA unexpected low " |
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295 | "while pulling SCL low!\n", name); |
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296 | goto bailout; |
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297 | } |
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298 | |||
299 | sclhi(adap); |
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300 | sda = getsda(adap); |
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301 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); |
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302 | if (!scl) { |
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303 | printk(KERN_WARNING "%s: SCL stuck low!\n", name); |
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304 | goto bailout; |
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305 | } |
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306 | if (!sda) { |
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307 | printk(KERN_WARNING "%s: SDA unexpected low " |
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308 | "while pulling SCL high!\n", name); |
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309 | goto bailout; |
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310 | } |
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1963 | serge | 311 | |
312 | if (adap->post_xfer) |
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313 | adap->post_xfer(i2c_adap); |
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314 | |||
3031 | serge | 315 | dbgprintf("%s: Test OK\n", name); |
1125 | serge | 316 | return 0; |
317 | bailout: |
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318 | sdahi(adap); |
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319 | sclhi(adap); |
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1963 | serge | 320 | |
321 | if (adap->post_xfer) |
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322 | adap->post_xfer(i2c_adap); |
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323 | |||
1125 | serge | 324 | return -ENODEV; |
325 | } |
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326 | |||
327 | /* ----- Utility functions |
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328 | */ |
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329 | |||
330 | /* try_address tries to contact a chip for a number of |
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331 | * times before it gives up. |
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332 | * return values: |
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333 | * 1 chip answered |
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334 | * 0 chip did not answer |
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335 | * -x transmission error |
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336 | */ |
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337 | static int try_address(struct i2c_adapter *i2c_adap, |
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338 | unsigned char addr, int retries) |
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339 | { |
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340 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
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341 | int i, ret = 0; |
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342 | |||
343 | for (i = 0; i <= retries; i++) { |
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344 | ret = i2c_outb(i2c_adap, addr); |
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345 | if (ret == 1 || i == retries) |
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346 | break; |
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347 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
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348 | i2c_stop(adap); |
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349 | udelay(adap->udelay); |
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350 | // yield(); |
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351 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
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352 | i2c_start(adap); |
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353 | } |
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354 | if (i && ret) |
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355 | bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at " |
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356 | "0x%02x: %s\n", i + 1, |
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357 | addr & 1 ? "read from" : "write to", addr >> 1, |
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358 | ret == 1 ? "success" : "failed, timeout?"); |
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359 | return ret; |
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360 | } |
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361 | |||
362 | static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
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363 | { |
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364 | const unsigned char *temp = msg->buf; |
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365 | int count = msg->len; |
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366 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; |
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367 | int retval; |
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368 | int wrcount = 0; |
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369 | |||
370 | while (count > 0) { |
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371 | retval = i2c_outb(i2c_adap, *temp); |
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372 | |||
373 | /* OK/ACK; or ignored NAK */ |
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374 | if ((retval > 0) || (nak_ok && (retval == 0))) { |
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375 | count--; |
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376 | temp++; |
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377 | wrcount++; |
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378 | |||
379 | /* A slave NAKing the master means the slave didn't like |
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380 | * something about the data it saw. For example, maybe |
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381 | * the SMBus PEC was wrong. |
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382 | */ |
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383 | } else if (retval == 0) { |
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3031 | serge | 384 | dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n"); |
1125 | serge | 385 | return -EIO; |
386 | |||
387 | /* Timeout; or (someday) lost arbitration |
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388 | * |
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389 | * FIXME Lost ARB implies retrying the transaction from |
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390 | * the first message, after the "winning" master issues |
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391 | * its STOP. As a rule, upper layer code has no reason |
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392 | * to know or care about this ... it is *NOT* an error. |
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393 | */ |
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394 | } else { |
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3031 | serge | 395 | dev_err(&i2c_adap->dev, "sendbytes: error %d\n", |
396 | retval); |
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1125 | serge | 397 | return retval; |
398 | } |
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399 | } |
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400 | return wrcount; |
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401 | } |
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402 | |||
403 | static int acknak(struct i2c_adapter *i2c_adap, int is_ack) |
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404 | { |
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405 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
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406 | |||
407 | /* assert: sda is high */ |
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408 | if (is_ack) /* send ack */ |
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409 | setsda(adap, 0); |
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410 | udelay((adap->udelay + 1) / 2); |
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411 | if (sclhi(adap) < 0) { /* timeout */ |
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3031 | serge | 412 | dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n"); |
413 | return -ETIMEDOUT; |
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1125 | serge | 414 | } |
415 | scllo(adap); |
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416 | return 0; |
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417 | } |
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418 | |||
419 | static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
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420 | { |
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421 | int inval; |
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422 | int rdcount = 0; /* counts bytes read */ |
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423 | unsigned char *temp = msg->buf; |
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424 | int count = msg->len; |
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425 | const unsigned flags = msg->flags; |
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426 | |||
427 | while (count > 0) { |
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428 | inval = i2c_inb(i2c_adap); |
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429 | if (inval >= 0) { |
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430 | *temp = inval; |
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431 | rdcount++; |
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432 | } else { /* read timed out */ |
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433 | break; |
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434 | } |
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435 | |||
436 | temp++; |
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437 | count--; |
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438 | |||
439 | /* Some SMBus transactions require that we receive the |
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440 | transaction length as the first read byte. */ |
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441 | if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) { |
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442 | if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) { |
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443 | if (!(flags & I2C_M_NO_RD_ACK)) |
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444 | acknak(i2c_adap, 0); |
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3031 | serge | 445 | dev_err(&i2c_adap->dev, "readbytes: invalid " |
446 | "block length (%d)\n", inval); |
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447 | return -EPROTO; |
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1125 | serge | 448 | } |
449 | /* The original count value accounts for the extra |
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450 | bytes, that is, either 1 for a regular transaction, |
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451 | or 2 for a PEC transaction. */ |
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452 | count += inval; |
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453 | msg->len += inval; |
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454 | } |
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455 | |||
1963 | serge | 456 | bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n", |
457 | inval, |
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458 | (flags & I2C_M_NO_RD_ACK) |
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459 | ? "(no ack/nak)" |
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460 | : (count ? "A" : "NA")); |
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1125 | serge | 461 | |
462 | if (!(flags & I2C_M_NO_RD_ACK)) { |
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463 | inval = acknak(i2c_adap, count); |
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464 | if (inval < 0) |
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465 | return inval; |
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466 | } |
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467 | } |
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468 | return rdcount; |
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469 | } |
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470 | |||
471 | /* doAddress initiates the transfer by generating the start condition (in |
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472 | * try_address) and transmits the address in the necessary format to handle |
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473 | * reads, writes as well as 10bit-addresses. |
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474 | * returns: |
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475 | * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set |
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3031 | serge | 476 | * -x an error occurred (like: -ENXIO if the device did not answer, or |
1125 | serge | 477 | * -ETIMEDOUT, for example if the lines are stuck...) |
478 | */ |
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479 | static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
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480 | { |
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481 | unsigned short flags = msg->flags; |
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482 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; |
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483 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
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484 | |||
485 | unsigned char addr; |
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486 | int ret, retries; |
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487 | |||
488 | retries = nak_ok ? 0 : i2c_adap->retries; |
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489 | |||
490 | if (flags & I2C_M_TEN) { |
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491 | /* a ten bit address */ |
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3031 | serge | 492 | addr = 0xf0 | ((msg->addr >> 7) & 0x06); |
1125 | serge | 493 | bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); |
494 | /* try extended address code...*/ |
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495 | ret = try_address(i2c_adap, addr, retries); |
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496 | if ((ret != 1) && !nak_ok) { |
||
3031 | serge | 497 | dev_err(&i2c_adap->dev, |
498 | "died at extended address code\n"); |
||
499 | return -ENXIO; |
||
1125 | serge | 500 | } |
501 | /* the remaining 8 bit address */ |
||
3031 | serge | 502 | ret = i2c_outb(i2c_adap, msg->addr & 0xff); |
1125 | serge | 503 | if ((ret != 1) && !nak_ok) { |
504 | /* the chip did not ack / xmission error occurred */ |
||
3031 | serge | 505 | dev_err(&i2c_adap->dev, "died at 2nd address code\n"); |
506 | return -ENXIO; |
||
1125 | serge | 507 | } |
508 | if (flags & I2C_M_RD) { |
||
509 | bit_dbg(3, &i2c_adap->dev, "emitting repeated " |
||
510 | "start condition\n"); |
||
511 | i2c_repstart(adap); |
||
512 | /* okay, now switch into reading mode */ |
||
513 | addr |= 0x01; |
||
514 | ret = try_address(i2c_adap, addr, retries); |
||
515 | if ((ret != 1) && !nak_ok) { |
||
3031 | serge | 516 | dev_err(&i2c_adap->dev, |
517 | "died at repeated address code\n"); |
||
518 | return -EIO; |
||
1125 | serge | 519 | } |
520 | } |
||
521 | } else { /* normal 7bit address */ |
||
522 | addr = msg->addr << 1; |
||
523 | if (flags & I2C_M_RD) |
||
524 | addr |= 1; |
||
525 | if (flags & I2C_M_REV_DIR_ADDR) |
||
526 | addr ^= 1; |
||
527 | ret = try_address(i2c_adap, addr, retries); |
||
528 | if ((ret != 1) && !nak_ok) |
||
529 | return -ENXIO; |
||
530 | } |
||
531 | |||
532 | return 0; |
||
533 | } |
||
534 | |||
535 | static int bit_xfer(struct i2c_adapter *i2c_adap, |
||
536 | struct i2c_msg msgs[], int num) |
||
537 | { |
||
538 | struct i2c_msg *pmsg; |
||
539 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
||
540 | int i, ret; |
||
541 | unsigned short nak_ok; |
||
542 | |||
3031 | serge | 543 | if (adap->pre_xfer) { |
1963 | serge | 544 | ret = adap->pre_xfer(i2c_adap); |
545 | if (ret < 0) |
||
546 | return ret; |
||
547 | } |
||
548 | |||
1125 | serge | 549 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
550 | i2c_start(adap); |
||
551 | for (i = 0; i < num; i++) { |
||
552 | pmsg = &msgs[i]; |
||
553 | nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; |
||
554 | if (!(pmsg->flags & I2C_M_NOSTART)) { |
||
555 | if (i) { |
||
556 | bit_dbg(3, &i2c_adap->dev, "emitting " |
||
557 | "repeated start condition\n"); |
||
558 | i2c_repstart(adap); |
||
559 | } |
||
560 | ret = bit_doAddress(i2c_adap, pmsg); |
||
561 | if ((ret != 0) && !nak_ok) { |
||
562 | bit_dbg(1, &i2c_adap->dev, "NAK from " |
||
563 | "device addr 0x%02x msg #%d\n", |
||
564 | msgs[i].addr, i); |
||
565 | goto bailout; |
||
566 | } |
||
567 | } |
||
568 | if (pmsg->flags & I2C_M_RD) { |
||
569 | /* read bytes into buffer*/ |
||
570 | ret = readbytes(i2c_adap, pmsg); |
||
571 | if (ret >= 1) |
||
572 | bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n", |
||
573 | ret, ret == 1 ? "" : "s"); |
||
574 | if (ret < pmsg->len) { |
||
575 | if (ret >= 0) |
||
3031 | serge | 576 | ret = -EIO; |
1125 | serge | 577 | goto bailout; |
578 | } |
||
579 | } else { |
||
580 | /* write bytes from buffer */ |
||
581 | ret = sendbytes(i2c_adap, pmsg); |
||
582 | if (ret >= 1) |
||
583 | bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n", |
||
584 | ret, ret == 1 ? "" : "s"); |
||
585 | if (ret < pmsg->len) { |
||
586 | if (ret >= 0) |
||
3031 | serge | 587 | ret = -EIO; |
1125 | serge | 588 | goto bailout; |
589 | } |
||
590 | } |
||
591 | } |
||
592 | ret = i; |
||
593 | |||
594 | bailout: |
||
595 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
||
596 | i2c_stop(adap); |
||
1963 | serge | 597 | |
598 | if (adap->post_xfer) |
||
599 | adap->post_xfer(i2c_adap); |
||
1125 | serge | 600 | return ret; |
601 | } |
||
602 | |||
603 | static u32 bit_func(struct i2c_adapter *adap) |
||
604 | { |
||
3031 | serge | 605 | return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL | |
1125 | serge | 606 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
607 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | |
||
608 | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; |
||
609 | } |
||
610 | |||
611 | |||
612 | /* -----exported algorithm data: ------------------------------------- */ |
||
613 | |||
3031 | serge | 614 | const struct i2c_algorithm i2c_bit_algo = { |
1125 | serge | 615 | .master_xfer = bit_xfer, |
616 | .functionality = bit_func, |
||
617 | }; |
||
3031 | serge | 618 | EXPORT_SYMBOL(i2c_bit_algo); |
1125 | serge | 619 | |
620 | /* |
||
621 | * registering functions to load algorithms at runtime |
||
622 | */ |
||
1963 | serge | 623 | static int __i2c_bit_add_bus(struct i2c_adapter *adap, |
624 | int (*add_adapter)(struct i2c_adapter *)) |
||
1125 | serge | 625 | { |
626 | struct i2c_algo_bit_data *bit_adap = adap->algo_data; |
||
1963 | serge | 627 | int ret; |
1125 | serge | 628 | |
1963 | serge | 629 | if (bit_test) { |
630 | ret = test_bus(adap); |
||
3031 | serge | 631 | if (bit_test >= 2 && ret < 0) |
1963 | serge | 632 | return -ENODEV; |
633 | } |
||
1125 | serge | 634 | |
635 | /* register new adapter to i2c module... */ |
||
636 | adap->algo = &i2c_bit_algo; |
||
637 | adap->retries = 3; |
||
638 | |||
3031 | serge | 639 | /* Complain if SCL can't be read */ |
640 | if (bit_adap->getscl == NULL) { |
||
641 | dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n"); |
||
642 | dev_warn(&adap->dev, "Bus may be unreliable\n"); |
||
643 | } |
||
1125 | serge | 644 | return 0; |
645 | } |
||
646 | |||
647 | int i2c_bit_add_bus(struct i2c_adapter *adap) |
||
648 | { |
||
1963 | serge | 649 | return __i2c_bit_add_bus(adap, NULL); |
650 | }>>>>>><>>=>>=>>>>>> |
||
1125 | serge | 651 |