tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/version.h>
30#include <linux/delay.h>
31#include <linux/eeprom_93cx6.h>
32
33MODULE_AUTHOR("http://rt2x00.serialmonkey.com");
34MODULE_VERSION("1.0");
35MODULE_DESCRIPTION("EEPROM 93cx6 chip driver");
36MODULE_LICENSE("GPL");
37
38static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom)
39{
40 eeprom->reg_data_clock = 1;
41 eeprom->register_write(eeprom);
42
43 /*
44 * Add a short delay for the pulse to work.
45 * According to the specifications the "maximum minimum"
46 * time should be 450ns.
47 */
48 ndelay(450);
49}
50
51static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom)
52{
53 eeprom->reg_data_clock = 0;
54 eeprom->register_write(eeprom);
55
56 /*
57 * Add a short delay for the pulse to work.
58 * According to the specifications the "maximum minimum"
59 * time should be 450ns.
60 */
61 ndelay(450);
62}
63
64static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom)
65{
66 /*
67 * Clear all flags, and enable chip select.
68 */
69 eeprom->register_read(eeprom);
70 eeprom->reg_data_in = 0;
71 eeprom->reg_data_out = 0;
72 eeprom->reg_data_clock = 0;
73 eeprom->reg_chip_select = 1;
74 eeprom->register_write(eeprom);
75
76 /*
77 * kick a pulse.
78 */
79 eeprom_93cx6_pulse_high(eeprom);
80 eeprom_93cx6_pulse_low(eeprom);
81}
82
83static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom)
84{
85 /*
86 * Clear chip_select and data_in flags.
87 */
88 eeprom->register_read(eeprom);
89 eeprom->reg_data_in = 0;
90 eeprom->reg_chip_select = 0;
91 eeprom->register_write(eeprom);
92
93 /*
94 * kick a pulse.
95 */
96 eeprom_93cx6_pulse_high(eeprom);
97 eeprom_93cx6_pulse_low(eeprom);
98}
99
100static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom,
101 const u16 data, const u16 count)
102{
103 unsigned int i;
104
105 eeprom->register_read(eeprom);
106
107 /*
108 * Clear data flags.
109 */
110 eeprom->reg_data_in = 0;
111 eeprom->reg_data_out = 0;
112
113 /*
114 * Start writing all bits.
115 */
116 for (i = count; i > 0; i--) {
117 /*
118 * Check if this bit needs to be set.
119 */
120 eeprom->reg_data_in = !!(data & (1 << (i - 1)));
121
122 /*
123 * Write the bit to the eeprom register.
124 */
125 eeprom->register_write(eeprom);
126
127 /*
128 * Kick a pulse.
129 */
130 eeprom_93cx6_pulse_high(eeprom);
131 eeprom_93cx6_pulse_low(eeprom);
132 }
133
134 eeprom->reg_data_in = 0;
135 eeprom->register_write(eeprom);
136}
137
138static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,
139 u16 *data, const u16 count)
140{
141 unsigned int i;
142 u16 buf = 0;
143
144 eeprom->register_read(eeprom);
145
146 /*
147 * Clear data flags.
148 */
149 eeprom->reg_data_in = 0;
150 eeprom->reg_data_out = 0;
151
152 /*
153 * Start reading all bits.
154 */
155 for (i = count; i > 0; i--) {
156 eeprom_93cx6_pulse_high(eeprom);
157
158 eeprom->register_read(eeprom);
159
160 /*
161 * Clear data_in flag.
162 */
163 eeprom->reg_data_in = 0;
164
165 /*
166 * Read if the bit has been set.
167 */
168 if (eeprom->reg_data_out)
169 buf |= (1 << (i - 1));
170
171 eeprom_93cx6_pulse_low(eeprom);
172 }
173
174 *data = buf;
175}
176
177/**
178 * eeprom_93cx6_read - Read multiple words from eeprom
179 * @eeprom: Pointer to eeprom structure
180 * @word: Word index from where we should start reading
181 * @data: target pointer where the information will have to be stored
182 *
183 * This function will read the eeprom data as host-endian word
184 * into the given data pointer.
185 */
186void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word,
187 u16 *data)
188{
189 u16 command;
190
191 /*
192 * Initialize the eeprom register
193 */
194 eeprom_93cx6_startup(eeprom);
195
196 /*
197 * Select the read opcode and the word to be read.
198 */
199 command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word;
200 eeprom_93cx6_write_bits(eeprom, command,
201 PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
202
203 /*
204 * Read the requested 16 bits.
205 */
206 eeprom_93cx6_read_bits(eeprom, data, 16);
207
208 /*
209 * Cleanup eeprom register.
210 */
211 eeprom_93cx6_cleanup(eeprom);
212}
213EXPORT_SYMBOL_GPL(eeprom_93cx6_read);
214
215/**
216 * eeprom_93cx6_multiread - Read multiple words from eeprom
217 * @eeprom: Pointer to eeprom structure
218 * @word: Word index from where we should start reading
219 * @data: target pointer where the information will have to be stored
220 * @words: Number of words that should be read.
221 *
222 * This function will read all requested words from the eeprom,
223 * this is done by calling eeprom_93cx6_read() multiple times.
224 * But with the additional change that while the eeprom_93cx6_read
225 * will return host ordered bytes, this method will return little
226 * endian words.
227 */
228void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
229 __le16 *data, const u16 words)
230{
231 unsigned int i;
232 u16 tmp;
233
234 for (i = 0; i < words; i++) {
235 tmp = 0;
236 eeprom_93cx6_read(eeprom, word + i, &tmp);
237 data[i] = cpu_to_le16(tmp);
238 }
239}
240EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);
241