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 
52 static 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 
57 static 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 
63 static 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 
81 unsigned 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 	unsigned short 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 
123 int 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