1 /*
2 * L3 code
3 *
4 * Copyright (C) 2008, Christian Pellegrin <chripell@evolware.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 *
11 * based on:
12 *
13 * L3 bus algorithm module.
14 *
15 * Copyright (C) 2001 Russell King, All Rights Reserved.
16 *
17 *
18 */
19
20 #include <linux/module.h>
21 #include <linux/kernel.h>
22 #include <linux/delay.h>
23
24 #include <sound/l3.h>
25
26 /*
27 * Send one byte of data to the chip. Data is latched into the chip on
28 * the rising edge of the clock.
29 */
sendbyte(struct l3_pins * adap,unsigned int byte)30 static void sendbyte(struct l3_pins *adap, unsigned int byte)
31 {
32 int i;
33
34 for (i = 0; i < 8; i++) {
35 adap->setclk(0);
36 udelay(adap->data_hold);
37 adap->setdat(byte & 1);
38 udelay(adap->data_setup);
39 adap->setclk(1);
40 udelay(adap->clock_high);
41 byte >>= 1;
42 }
43 }
44
45 /*
46 * Send a set of bytes to the chip. We need to pulse the MODE line
47 * between each byte, but never at the start nor at the end of the
48 * transfer.
49 */
sendbytes(struct l3_pins * adap,const u8 * buf,int len)50 static void sendbytes(struct l3_pins *adap, const u8 *buf,
51 int len)
52 {
53 int i;
54
55 for (i = 0; i < len; i++) {
56 if (i) {
57 udelay(adap->mode_hold);
58 adap->setmode(0);
59 udelay(adap->mode);
60 }
61 adap->setmode(1);
62 udelay(adap->mode_setup);
63 sendbyte(adap, buf[i]);
64 }
65 }
66
l3_write(struct l3_pins * adap,u8 addr,u8 * data,int len)67 int l3_write(struct l3_pins *adap, u8 addr, u8 *data, int len)
68 {
69 adap->setclk(1);
70 adap->setdat(1);
71 adap->setmode(1);
72 udelay(adap->mode);
73
74 adap->setmode(0);
75 udelay(adap->mode_setup);
76 sendbyte(adap, addr);
77 udelay(adap->mode_hold);
78
79 sendbytes(adap, data, len);
80
81 adap->setclk(1);
82 adap->setdat(1);
83 adap->setmode(0);
84
85 return len;
86 }
87 EXPORT_SYMBOL_GPL(l3_write);
88
89 MODULE_DESCRIPTION("L3 bit-banging driver");
90 MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
91 MODULE_LICENSE("GPL");
92