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1 /** |
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2 Network Driver for Beckhoff CCAT communication controller |
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3 Copyright (C) 2014 Beckhoff Automation GmbH |
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4 Author: Patrick Bruenn <p.bruenn@beckhoff.com> |
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5 |
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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 |
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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 |
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16 You should have received a copy of the GNU General Public License along |
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17 with this program; if not, write to the Free Software Foundation, Inc., |
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18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
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19 */ |
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20 |
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21 #include <linux/kernel.h> |
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22 #include <linux/module.h> |
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23 #include <linux/gpio.h> |
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24 #include <linux/version.h> |
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25 #include "module.h" |
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26 |
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27 /** |
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28 * struct ccat_gpio - CCAT GPIO function |
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29 * @ioaddr: PCI base address of the CCAT Update function |
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30 * @info: holds a copy of the CCAT Update function information block (read from PCI config space) |
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31 */ |
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32 struct ccat_gpio { |
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33 struct gpio_chip chip; |
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34 void __iomem *ioaddr; |
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35 struct mutex lock; |
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36 }; |
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37 |
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38 /** TODO implement in LED driver |
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39 #define TC_RED 0x01 |
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40 #define TC_GREEN 0x02 |
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41 #define TC_BLUE 0x04 |
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42 #define FB1_RED 0x08 |
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43 #define FB1_GREEN 0x10 |
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44 #define FB1_BLUE 0x20 |
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45 #define FB2_RED 0x40 |
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46 #define FB2_GREEN 0x80 |
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47 #define FB2_BLUE 0x100 |
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48 */ |
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49 |
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50 static int set_bit_in_register(struct mutex *lock, void __iomem * ioaddr, |
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51 unsigned nr, int val) |
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52 { |
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53 volatile unsigned long old; |
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54 |
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55 mutex_lock(lock); |
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56 old = ioread32(ioaddr); |
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57 val ? set_bit(nr, &old) : clear_bit(nr, &old); |
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58 if (val) |
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59 set_bit(nr, &old); |
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60 else |
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61 clear_bit(nr, &old); |
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62 iowrite32(old, ioaddr); |
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63 mutex_unlock(lock); |
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64 return 0; |
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65 } |
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66 |
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67 static int ccat_gpio_get_direction(struct gpio_chip *chip, unsigned nr) |
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68 { |
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69 struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip); |
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70 const size_t byte_offset = 4 * (nr / 32) + 0x8; |
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71 const u32 mask = 1 << (nr % 32); |
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72 |
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73 return !(mask & ioread32(gdev->ioaddr + byte_offset)); |
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74 } |
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75 |
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76 static int ccat_gpio_direction_input(struct gpio_chip *chip, unsigned nr) |
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77 { |
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78 struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip); |
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79 |
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80 return set_bit_in_register(&gdev->lock, gdev->ioaddr + 0x8, nr, 0); |
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81 } |
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82 |
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83 static int ccat_gpio_direction_output(struct gpio_chip *chip, unsigned nr, |
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84 int val) |
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85 { |
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86 struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip); |
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87 |
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88 return set_bit_in_register(&gdev->lock, gdev->ioaddr + 0x8, nr, 1); |
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89 } |
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90 |
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91 static int ccat_gpio_get(struct gpio_chip *chip, unsigned nr) |
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92 { |
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93 struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip); |
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94 const size_t byte_off = 4 * (nr / 32); |
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95 const int mask = 1 << (nr % 32); |
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96 int dir_off; |
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97 int value; |
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98 |
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99 /** omit direction changes before value was read */ |
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100 mutex_lock(&gdev->lock); |
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101 dir_off = 0x10 * ccat_gpio_get_direction(chip, nr); |
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102 value = !(mask & ioread32(gdev->ioaddr + byte_off + dir_off)); |
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103 mutex_unlock(&gdev->lock); |
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104 return value; |
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105 } |
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106 |
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107 static void ccat_gpio_set(struct gpio_chip *chip, unsigned nr, int val) |
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108 { |
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109 struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip); |
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110 |
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111 set_bit_in_register(&gdev->lock, gdev->ioaddr, nr, val); |
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112 } |
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113 |
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114 static const struct gpio_chip ccat_gpio_chip = { |
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115 .label = KBUILD_MODNAME, |
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116 .owner = THIS_MODULE, |
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117 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,12,0)) |
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118 .get_direction = ccat_gpio_get_direction, |
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119 #endif |
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120 .direction_input = ccat_gpio_direction_input, |
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121 .get = ccat_gpio_get, |
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122 .direction_output = ccat_gpio_direction_output, |
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123 .set = ccat_gpio_set, |
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124 .dbg_show = NULL, |
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125 .base = -1, |
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126 .can_sleep = false |
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127 }; |
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128 |
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129 static int ccat_gpio_probe(struct ccat_function *func) |
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130 { |
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131 struct ccat_gpio *const gpio = kzalloc(sizeof(*gpio), GFP_KERNEL); |
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132 int ret; |
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133 |
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134 if (!gpio) |
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135 return -ENOMEM; |
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136 |
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137 gpio->ioaddr = func->ccat->bar_0 + func->info.addr; |
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138 memcpy(&gpio->chip, &ccat_gpio_chip, sizeof(gpio->chip)); |
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139 gpio->chip.ngpio = func->info.num_gpios; |
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140 mutex_init(&gpio->lock); |
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141 |
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142 ret = gpiochip_add(&gpio->chip); |
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143 if (ret) { |
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144 kfree(gpio); |
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145 return ret; |
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146 } |
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147 pr_info("registered %s as gpiochip%d with #%d GPIOs.\n", |
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148 gpio->chip.label, gpio->chip.base, gpio->chip.ngpio); |
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149 func->private_data = gpio; |
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150 return 0; |
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151 } |
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152 |
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153 static void ccat_gpio_remove(struct ccat_function *func) |
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154 { |
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155 struct ccat_gpio *const gpio = func->private_data; |
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156 |
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157 gpiochip_remove(&gpio->chip); |
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158 }; |
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159 |
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160 const struct ccat_driver gpio_driver = { |
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161 .type = CCATINFO_GPIO, |
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162 .probe = ccat_gpio_probe, |
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163 .remove = ccat_gpio_remove, |
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164 }; |