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Rev | Author | Line No. | Line |
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1125 | serge | 1 | /* i2c-core.c - a device driver for the iic-bus interface */ |
2 | /* ------------------------------------------------------------------------- */ |
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3 | /* Copyright (C) 1995-99 Simon G. Vogl |
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4 | |||
5 | This program is free software; you can redistribute it and/or modify |
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6 | it under the terms of the GNU General Public License as published by |
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7 | the Free Software Foundation; either version 2 of the License, or |
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8 | (at your option) any later version. |
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9 | |||
10 | This program is distributed in the hope that it will be useful, |
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11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 | GNU General Public License for more details. |
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14 | |||
15 | You should have received a copy of the GNU General Public License |
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16 | along with this program; if not, write to the Free Software |
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3031 | serge | 17 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
18 | MA 02110-1301 USA. */ |
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1125 | serge | 19 | /* ------------------------------------------------------------------------- */ |
20 | |||
21 | /* With some changes from Kyösti Mälkki |
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22 | All SMBus-related things are written by Frodo Looijaard |
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23 | SMBus 2.0 support by Mark Studebaker |
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3031 | serge | 24 | Jean Delvare |
25 | Mux support by Rodolfo Giometti |
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26 | Michael Lawnick |
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1125 | serge | 27 | |
3031 | serge | 28 | #include |
29 | #include |
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5271 | serge | 30 | #include |
3031 | serge | 31 | #include |
5271 | serge | 32 | #include |
33 | #include |
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1125 | serge | 34 | #include |
5271 | serge | 35 | #include |
1125 | serge | 36 | #include |
37 | |||
38 | |||
3031 | serge | 39 | |
40 | #if 0 |
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41 | |||
42 | static ssize_t |
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43 | show_modalias(struct device *dev, struct device_attribute *attr, char *buf) |
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44 | { |
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45 | struct i2c_client *client = to_i2c_client(dev); |
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46 | return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); |
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47 | } |
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48 | |||
49 | static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); |
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50 | static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL); |
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51 | |||
52 | static struct attribute *i2c_dev_attrs[] = { |
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53 | &dev_attr_name.attr, |
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54 | /* modalias helps coldplug: modprobe $(cat .../modalias) */ |
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55 | &dev_attr_modalias.attr, |
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56 | NULL |
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57 | }; |
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58 | |||
59 | static struct attribute_group i2c_dev_attr_group = { |
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60 | .attrs = i2c_dev_attrs, |
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61 | }; |
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62 | |||
63 | static const struct attribute_group *i2c_dev_attr_groups[] = { |
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64 | &i2c_dev_attr_group, |
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65 | NULL |
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66 | }; |
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67 | |||
68 | static const struct dev_pm_ops i2c_device_pm_ops = { |
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69 | .suspend = i2c_device_pm_suspend, |
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70 | .resume = i2c_device_pm_resume, |
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71 | .freeze = i2c_device_pm_freeze, |
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72 | .thaw = i2c_device_pm_thaw, |
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73 | .poweroff = i2c_device_pm_poweroff, |
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74 | .restore = i2c_device_pm_restore, |
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75 | SET_RUNTIME_PM_OPS( |
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76 | pm_generic_runtime_suspend, |
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77 | pm_generic_runtime_resume, |
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4104 | Serge | 78 | NULL |
3031 | serge | 79 | ) |
80 | }; |
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81 | |||
82 | struct bus_type i2c_bus_type = { |
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83 | .name = "i2c", |
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84 | .match = i2c_device_match, |
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85 | .probe = i2c_device_probe, |
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86 | .remove = i2c_device_remove, |
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87 | .shutdown = i2c_device_shutdown, |
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88 | .pm = &i2c_device_pm_ops, |
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89 | }; |
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90 | EXPORT_SYMBOL_GPL(i2c_bus_type); |
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91 | |||
92 | static struct device_type i2c_client_type = { |
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93 | .groups = i2c_dev_attr_groups, |
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94 | .uevent = i2c_device_uevent, |
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95 | .release = i2c_client_dev_release, |
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96 | }; |
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97 | |||
98 | |||
1125 | serge | 99 | /** |
3031 | serge | 100 | * i2c_verify_client - return parameter as i2c_client, or NULL |
101 | * @dev: device, probably from some driver model iterator |
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102 | * |
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103 | * When traversing the driver model tree, perhaps using driver model |
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104 | * iterators like @device_for_each_child(), you can't assume very much |
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105 | * about the nodes you find. Use this function to avoid oopses caused |
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106 | * by wrongly treating some non-I2C device as an i2c_client. |
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107 | */ |
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108 | struct i2c_client *i2c_verify_client(struct device *dev) |
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109 | { |
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110 | return (dev->type == &i2c_client_type) |
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111 | ? to_i2c_client(dev) |
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112 | : NULL; |
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113 | } |
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114 | EXPORT_SYMBOL(i2c_verify_client); |
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115 | |||
116 | |||
117 | /* This is a permissive address validity check, I2C address map constraints |
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118 | * are purposely not enforced, except for the general call address. */ |
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119 | static int i2c_check_client_addr_validity(const struct i2c_client *client) |
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120 | { |
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121 | if (client->flags & I2C_CLIENT_TEN) { |
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122 | /* 10-bit address, all values are valid */ |
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123 | if (client->addr > 0x3ff) |
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124 | return -EINVAL; |
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125 | } else { |
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126 | /* 7-bit address, reject the general call address */ |
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127 | if (client->addr == 0x00 || client->addr > 0x7f) |
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128 | return -EINVAL; |
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129 | } |
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130 | return 0; |
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131 | } |
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132 | |||
133 | /* And this is a strict address validity check, used when probing. If a |
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134 | * device uses a reserved address, then it shouldn't be probed. 7-bit |
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135 | * addressing is assumed, 10-bit address devices are rare and should be |
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136 | * explicitly enumerated. */ |
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137 | static int i2c_check_addr_validity(unsigned short addr) |
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138 | { |
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139 | /* |
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140 | * Reserved addresses per I2C specification: |
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141 | * 0x00 General call address / START byte |
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142 | * 0x01 CBUS address |
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143 | * 0x02 Reserved for different bus format |
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144 | * 0x03 Reserved for future purposes |
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145 | * 0x04-0x07 Hs-mode master code |
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146 | * 0x78-0x7b 10-bit slave addressing |
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147 | * 0x7c-0x7f Reserved for future purposes |
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148 | */ |
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149 | if (addr < 0x08 || addr > 0x77) |
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150 | return -EINVAL; |
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151 | return 0; |
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152 | } |
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153 | |||
154 | static int __i2c_check_addr_busy(struct device *dev, void *addrp) |
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155 | { |
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156 | struct i2c_client *client = i2c_verify_client(dev); |
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157 | int addr = *(int *)addrp; |
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158 | |||
159 | if (client && client->addr == addr) |
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160 | return -EBUSY; |
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161 | return 0; |
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162 | } |
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163 | |||
164 | /* walk up mux tree */ |
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165 | static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) |
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166 | { |
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167 | struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); |
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168 | int result; |
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169 | |||
170 | result = device_for_each_child(&adapter->dev, &addr, |
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171 | __i2c_check_addr_busy); |
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172 | |||
173 | if (!result && parent) |
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174 | result = i2c_check_mux_parents(parent, addr); |
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175 | |||
176 | return result; |
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177 | } |
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178 | |||
179 | /* recurse down mux tree */ |
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180 | static int i2c_check_mux_children(struct device *dev, void *addrp) |
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181 | { |
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182 | int result; |
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183 | |||
184 | if (dev->type == &i2c_adapter_type) |
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185 | result = device_for_each_child(dev, addrp, |
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186 | i2c_check_mux_children); |
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187 | else |
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188 | result = __i2c_check_addr_busy(dev, addrp); |
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189 | |||
190 | return result; |
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191 | } |
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192 | |||
193 | static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) |
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194 | { |
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195 | struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); |
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196 | int result = 0; |
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197 | |||
198 | if (parent) |
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199 | result = i2c_check_mux_parents(parent, addr); |
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200 | |||
201 | if (!result) |
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202 | result = device_for_each_child(&adapter->dev, &addr, |
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203 | i2c_check_mux_children); |
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204 | |||
205 | return result; |
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206 | } |
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207 | |||
208 | /** |
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209 | * i2c_lock_adapter - Get exclusive access to an I2C bus segment |
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210 | * @adapter: Target I2C bus segment |
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211 | */ |
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212 | void i2c_lock_adapter(struct i2c_adapter *adapter) |
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213 | { |
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214 | struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); |
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215 | |||
216 | if (parent) |
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217 | i2c_lock_adapter(parent); |
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218 | else |
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219 | rt_mutex_lock(&adapter->bus_lock); |
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220 | } |
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221 | EXPORT_SYMBOL_GPL(i2c_lock_adapter); |
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222 | |||
223 | /** |
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224 | * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment |
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225 | * @adapter: Target I2C bus segment |
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226 | */ |
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227 | static int i2c_trylock_adapter(struct i2c_adapter *adapter) |
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228 | { |
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229 | struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); |
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230 | |||
231 | if (parent) |
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232 | return i2c_trylock_adapter(parent); |
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233 | else |
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234 | return rt_mutex_trylock(&adapter->bus_lock); |
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235 | } |
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236 | |||
237 | /** |
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238 | * i2c_unlock_adapter - Release exclusive access to an I2C bus segment |
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239 | * @adapter: Target I2C bus segment |
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240 | */ |
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241 | void i2c_unlock_adapter(struct i2c_adapter *adapter) |
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242 | { |
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243 | struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); |
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244 | |||
245 | if (parent) |
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246 | i2c_unlock_adapter(parent); |
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247 | else |
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248 | rt_mutex_unlock(&adapter->bus_lock); |
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249 | } |
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250 | EXPORT_SYMBOL_GPL(i2c_unlock_adapter); |
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251 | |||
252 | #endif |
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253 | |||
254 | |||
255 | /** |
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1125 | serge | 256 | * i2c_transfer - execute a single or combined I2C message |
257 | * @adap: Handle to I2C bus |
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258 | * @msgs: One or more messages to execute before STOP is issued to |
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259 | * terminate the operation; each message begins with a START. |
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260 | * @num: Number of messages to be executed. |
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261 | * |
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262 | * Returns negative errno, else the number of messages executed. |
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263 | * |
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264 | * Note that there is no requirement that each message be sent to |
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265 | * the same slave address, although that is the most common model. |
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266 | */ |
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267 | int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) |
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268 | { |
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269 | unsigned long orig_jiffies; |
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270 | int ret, try; |
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271 | |||
272 | /* REVISIT the fault reporting model here is weak: |
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273 | * |
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274 | * - When we get an error after receiving N bytes from a slave, |
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275 | * there is no way to report "N". |
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276 | * |
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277 | * - When we get a NAK after transmitting N bytes to a slave, |
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278 | * there is no way to report "N" ... or to let the master |
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279 | * continue executing the rest of this combined message, if |
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280 | * that's the appropriate response. |
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281 | * |
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282 | * - When for example "num" is two and we successfully complete |
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283 | * the first message but get an error part way through the |
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284 | * second, it's unclear whether that should be reported as |
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285 | * one (discarding status on the second message) or errno |
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286 | * (discarding status on the first one). |
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287 | */ |
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288 | |||
289 | if (adap->algo->master_xfer) { |
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290 | |||
3031 | serge | 291 | /* Retry automatically on arbitration loss */ |
292 | orig_jiffies = GetTimerTicks(); |
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1125 | serge | 293 | |
294 | for (ret = 0, try = 0; try <= adap->retries; try++) { |
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1963 | serge | 295 | |
1125 | serge | 296 | ret = adap->algo->master_xfer(adap, msgs, num); |
297 | if (ret != -EAGAIN) |
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298 | break; |
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3031 | serge | 299 | |
5271 | serge | 300 | if (time_after((unsigned long)GetTimerTicks(), orig_jiffies + adap->timeout)) |
3031 | serge | 301 | break; |
302 | |||
303 | delay(1); |
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1125 | serge | 304 | } |
305 | // mutex_unlock(&adap->bus_lock); |
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306 | return ret; |
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307 | } else { |
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3031 | serge | 308 | dbgprintf("I2C level transfers not supported\n"); |
1125 | serge | 309 | return -EOPNOTSUPP; |
310 | } |
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311 | } |
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312 | EXPORT_SYMBOL(i2c_transfer); |
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313 | |||
314 | |||
1963 | serge | 315 | /** |
316 | * i2c_new_device - instantiate an i2c device |
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317 | * @adap: the adapter managing the device |
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318 | * @info: describes one I2C device; bus_num is ignored |
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319 | * Context: can sleep |
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320 | * |
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321 | * Create an i2c device. Binding is handled through driver model |
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322 | * probe()/remove() methods. A driver may be bound to this device when we |
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323 | * return from this function, or any later moment (e.g. maybe hotplugging will |
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324 | * load the driver module). This call is not appropriate for use by mainboard |
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325 | * initialization logic, which usually runs during an arch_initcall() long |
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326 | * before any i2c_adapter could exist. |
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327 | * |
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328 | * This returns the new i2c client, which may be saved for later use with |
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329 | * i2c_unregister_device(); or NULL to indicate an error. |
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330 | */ |
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331 | struct i2c_client * |
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332 | i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info) |
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333 | { |
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334 | struct i2c_client *client; |
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335 | int status; |
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1125 | serge | 336 | |
1963 | serge | 337 | client = kzalloc(sizeof *client, GFP_KERNEL); |
338 | if (!client) |
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339 | return NULL; |
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1125 | serge | 340 | |
1963 | serge | 341 | client->adapter = adap; |
1125 | serge | 342 | |
1963 | serge | 343 | client->flags = info->flags; |
344 | client->addr = info->addr; |
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345 | client->irq = info->irq; |
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346 | |||
347 | strlcpy(client->name, info->type, sizeof(client->name)); |
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348 | |||
349 | return client; |
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350 | }=>> |
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351 |