1/*
2 * Copyright (C) 2010-2013 Bluecherry, LLC <http://www.bluecherrydvr.com>
3 *
4 * Original author:
5 * Ben Collins <bcollins@ubuntu.com>
6 *
7 * Additional work by:
8 * John Brooks <john.brooks@bluecherry.net>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 * GNU General Public License for more details.
19 */
20
21#include <linux/kernel.h>
22#include <linux/delay.h>
23
24#include "solo6x10.h"
25
26/* Control */
27#define EE_SHIFT_CLK	0x04
28#define EE_CS		0x08
29#define EE_DATA_WRITE	0x02
30#define EE_DATA_READ	0x01
31#define EE_ENB		(0x80 | EE_CS)
32
33#define eeprom_delay()	udelay(100)
34#if 0
35#define eeprom_delay()	solo_reg_read(solo_dev, SOLO_EEPROM_CTRL)
36#define eeprom_delay()	({				\
37	int i, ret;					\
38	udelay(100);					\
39	for (i = ret = 0; i < 1000 && !ret; i++)	\
40		ret = solo_eeprom_reg_read(solo_dev);	\
41})
42#endif
43#define ADDR_LEN	6
44
45/* Commands */
46#define EE_EWEN_CMD	4
47#define EE_EWDS_CMD	4
48#define EE_WRITE_CMD	5
49#define EE_READ_CMD	6
50#define EE_ERASE_CMD	7
51
52static unsigned int solo_eeprom_reg_read(struct solo_dev *solo_dev)
53{
54	return solo_reg_read(solo_dev, SOLO_EEPROM_CTRL) & EE_DATA_READ;
55}
56
57static void solo_eeprom_reg_write(struct solo_dev *solo_dev, u32 data)
58{
59	solo_reg_write(solo_dev, SOLO_EEPROM_CTRL, data);
60	eeprom_delay();
61}
62
63static void solo_eeprom_cmd(struct solo_dev *solo_dev, int cmd)
64{
65	int i;
66
67	solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ACCESS_EN);
68	solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE);
69
70	for (i = 4 + ADDR_LEN; i >= 0; i--) {
71		int dataval = (cmd & (1 << i)) ? EE_DATA_WRITE : 0;
72
73		solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE | dataval);
74		solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE |
75				      EE_SHIFT_CLK | dataval);
76	}
77
78	solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE);
79}
80
81unsigned int solo_eeprom_ewen(struct solo_dev *solo_dev, int w_en)
82{
83	int ewen_cmd = (w_en ? 0x3f : 0) | (EE_EWEN_CMD << ADDR_LEN);
84	unsigned int retval = 0;
85	int i;
86
87	solo_eeprom_cmd(solo_dev, ewen_cmd);
88
89	for (i = 0; i < 16; i++) {
90		solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE |
91				      EE_SHIFT_CLK);
92		retval = (retval << 1) | solo_eeprom_reg_read(solo_dev);
93		solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE);
94		retval = (retval << 1) | solo_eeprom_reg_read(solo_dev);
95	}
96
97	solo_eeprom_reg_write(solo_dev, ~EE_CS);
98	retval = (retval << 1) | solo_eeprom_reg_read(solo_dev);
99
100	return retval;
101}
102
103__be16 solo_eeprom_read(struct solo_dev *solo_dev, int loc)
104{
105	int read_cmd = loc | (EE_READ_CMD << ADDR_LEN);
106	u16 retval = 0;
107	int i;
108
109	solo_eeprom_cmd(solo_dev, read_cmd);
110
111	for (i = 0; i < 16; i++) {
112		solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE |
113				      EE_SHIFT_CLK);
114		retval = (retval << 1) | solo_eeprom_reg_read(solo_dev);
115		solo_eeprom_reg_write(solo_dev, SOLO_EEPROM_ENABLE);
116	}
117
118	solo_eeprom_reg_write(solo_dev, ~EE_CS);
119
120	return (__force __be16)retval;
121}
122
123int solo_eeprom_write(struct solo_dev *solo_dev, int loc,
124		      __be16 data)
125{
126	int write_cmd = loc | (EE_WRITE_CMD << ADDR_LEN);
127	unsigned int retval;
128	int i;
129
130	solo_eeprom_cmd(solo_dev, write_cmd);
131
132	for (i = 15; i >= 0; i--) {
133		unsigned int dataval = ((__force unsigned)data >> i) & 1;
134
135		solo_eeprom_reg_write(solo_dev, EE_ENB);
136		solo_eeprom_reg_write(solo_dev,
137				      EE_ENB | (dataval << 1) | EE_SHIFT_CLK);
138	}
139
140	solo_eeprom_reg_write(solo_dev, EE_ENB);
141	solo_eeprom_reg_write(solo_dev, ~EE_CS);
142	solo_eeprom_reg_write(solo_dev, EE_ENB);
143
144	for (i = retval = 0; i < 10000 && !retval; i++)
145		retval = solo_eeprom_reg_read(solo_dev);
146
147	solo_eeprom_reg_write(solo_dev, ~EE_CS);
148
149	return !retval;
150}
151