1 /* 2 Copyright (C) 2004 - 2006 rt2x00 SourceForge Project 3 <http://rt2x00.serialmonkey.com> 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; if not, write to the 17 Free Software Foundation, Inc., 18 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 19 */ 20 21 /* 22 Module: eeprom_93cx6 23 Abstract: EEPROM reader routines for 93cx6 chipsets. 24 Supported chipsets: 93c46 & 93c66. 25 */ 26 27 #include <linux/kernel.h> 28 #include <linux/module.h> 29 #include <linux/delay.h> 30 #include <linux/eeprom_93cx6.h> 31 32 MODULE_AUTHOR("http://rt2x00.serialmonkey.com"); 33 MODULE_VERSION("1.0"); 34 MODULE_DESCRIPTION("EEPROM 93cx6 chip driver"); 35 MODULE_LICENSE("GPL"); 36 37 static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom) 38 { 39 eeprom->reg_data_clock = 1; 40 eeprom->register_write(eeprom); 41 42 /* 43 * Add a short delay for the pulse to work. 44 * According to the specifications the "maximum minimum" 45 * time should be 450ns. 46 */ 47 ndelay(450); 48 } 49 50 static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom) 51 { 52 eeprom->reg_data_clock = 0; 53 eeprom->register_write(eeprom); 54 55 /* 56 * Add a short delay for the pulse to work. 57 * According to the specifications the "maximum minimum" 58 * time should be 450ns. 59 */ 60 ndelay(450); 61 } 62 63 static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom) 64 { 65 /* 66 * Clear all flags, and enable chip select. 67 */ 68 eeprom->register_read(eeprom); 69 eeprom->reg_data_in = 0; 70 eeprom->reg_data_out = 0; 71 eeprom->reg_data_clock = 0; 72 eeprom->reg_chip_select = 1; 73 eeprom->register_write(eeprom); 74 75 /* 76 * kick a pulse. 77 */ 78 eeprom_93cx6_pulse_high(eeprom); 79 eeprom_93cx6_pulse_low(eeprom); 80 } 81 82 static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom) 83 { 84 /* 85 * Clear chip_select and data_in flags. 86 */ 87 eeprom->register_read(eeprom); 88 eeprom->reg_data_in = 0; 89 eeprom->reg_chip_select = 0; 90 eeprom->register_write(eeprom); 91 92 /* 93 * kick a pulse. 94 */ 95 eeprom_93cx6_pulse_high(eeprom); 96 eeprom_93cx6_pulse_low(eeprom); 97 } 98 99 static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom, 100 const u16 data, const u16 count) 101 { 102 unsigned int i; 103 104 eeprom->register_read(eeprom); 105 106 /* 107 * Clear data flags. 108 */ 109 eeprom->reg_data_in = 0; 110 eeprom->reg_data_out = 0; 111 112 /* 113 * Start writing all bits. 114 */ 115 for (i = count; i > 0; i--) { 116 /* 117 * Check if this bit needs to be set. 118 */ 119 eeprom->reg_data_in = !!(data & (1 << (i - 1))); 120 121 /* 122 * Write the bit to the eeprom register. 123 */ 124 eeprom->register_write(eeprom); 125 126 /* 127 * Kick a pulse. 128 */ 129 eeprom_93cx6_pulse_high(eeprom); 130 eeprom_93cx6_pulse_low(eeprom); 131 } 132 133 eeprom->reg_data_in = 0; 134 eeprom->register_write(eeprom); 135 } 136 137 static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom, 138 u16 *data, const u16 count) 139 { 140 unsigned int i; 141 u16 buf = 0; 142 143 eeprom->register_read(eeprom); 144 145 /* 146 * Clear data flags. 147 */ 148 eeprom->reg_data_in = 0; 149 eeprom->reg_data_out = 0; 150 151 /* 152 * Start reading all bits. 153 */ 154 for (i = count; i > 0; i--) { 155 eeprom_93cx6_pulse_high(eeprom); 156 157 eeprom->register_read(eeprom); 158 159 /* 160 * Clear data_in flag. 161 */ 162 eeprom->reg_data_in = 0; 163 164 /* 165 * Read if the bit has been set. 166 */ 167 if (eeprom->reg_data_out) 168 buf |= (1 << (i - 1)); 169 170 eeprom_93cx6_pulse_low(eeprom); 171 } 172 173 *data = buf; 174 } 175 176 /** 177 * eeprom_93cx6_read - Read multiple words from eeprom 178 * @eeprom: Pointer to eeprom structure 179 * @word: Word index from where we should start reading 180 * @data: target pointer where the information will have to be stored 181 * 182 * This function will read the eeprom data as host-endian word 183 * into the given data pointer. 184 */ 185 void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word, 186 u16 *data) 187 { 188 u16 command; 189 190 /* 191 * Initialize the eeprom register 192 */ 193 eeprom_93cx6_startup(eeprom); 194 195 /* 196 * Select the read opcode and the word to be read. 197 */ 198 command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word; 199 eeprom_93cx6_write_bits(eeprom, command, 200 PCI_EEPROM_WIDTH_OPCODE + eeprom->width); 201 202 /* 203 * Read the requested 16 bits. 204 */ 205 eeprom_93cx6_read_bits(eeprom, data, 16); 206 207 /* 208 * Cleanup eeprom register. 209 */ 210 eeprom_93cx6_cleanup(eeprom); 211 } 212 EXPORT_SYMBOL_GPL(eeprom_93cx6_read); 213 214 /** 215 * eeprom_93cx6_multiread - Read multiple words from eeprom 216 * @eeprom: Pointer to eeprom structure 217 * @word: Word index from where we should start reading 218 * @data: target pointer where the information will have to be stored 219 * @words: Number of words that should be read. 220 * 221 * This function will read all requested words from the eeprom, 222 * this is done by calling eeprom_93cx6_read() multiple times. 223 * But with the additional change that while the eeprom_93cx6_read 224 * will return host ordered bytes, this method will return little 225 * endian words. 226 */ 227 void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word, 228 __le16 *data, const u16 words) 229 { 230 unsigned int i; 231 u16 tmp; 232 233 for (i = 0; i < words; i++) { 234 tmp = 0; 235 eeprom_93cx6_read(eeprom, word + i, &tmp); 236 data[i] = cpu_to_le16(tmp); 237 } 238 } 239 EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread); 240 241