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 #include <linux/device.h>
24 #include <linux/gpio.h>
25
26 #include <sound/l3.h>
27
28 /*
29 * Send one byte of data to the chip. Data is latched into the chip on
30 * the rising edge of the clock.
31 */
sendbyte(struct l3_pins * adap,unsigned int byte)32 static void sendbyte(struct l3_pins *adap, unsigned int byte)
33 {
34 int i;
35
36 for (i = 0; i < 8; i++) {
37 adap->setclk(adap, 0);
38 udelay(adap->data_hold);
39 adap->setdat(adap, byte & 1);
40 udelay(adap->data_setup);
41 adap->setclk(adap, 1);
42 udelay(adap->clock_high);
43 byte >>= 1;
44 }
45 }
46
47 /*
48 * Send a set of bytes to the chip. We need to pulse the MODE line
49 * between each byte, but never at the start nor at the end of the
50 * transfer.
51 */
sendbytes(struct l3_pins * adap,const u8 * buf,int len)52 static void sendbytes(struct l3_pins *adap, const u8 *buf,
53 int len)
54 {
55 int i;
56
57 for (i = 0; i < len; i++) {
58 if (i) {
59 udelay(adap->mode_hold);
60 adap->setmode(adap, 0);
61 udelay(adap->mode);
62 }
63 adap->setmode(adap, 1);
64 udelay(adap->mode_setup);
65 sendbyte(adap, buf[i]);
66 }
67 }
68
l3_write(struct l3_pins * adap,u8 addr,u8 * data,int len)69 int l3_write(struct l3_pins *adap, u8 addr, u8 *data, int len)
70 {
71 adap->setclk(adap, 1);
72 adap->setdat(adap, 1);
73 adap->setmode(adap, 1);
74 udelay(adap->mode);
75
76 adap->setmode(adap, 0);
77 udelay(adap->mode_setup);
78 sendbyte(adap, addr);
79 udelay(adap->mode_hold);
80
81 sendbytes(adap, data, len);
82
83 adap->setclk(adap, 1);
84 adap->setdat(adap, 1);
85 adap->setmode(adap, 0);
86
87 return len;
88 }
89 EXPORT_SYMBOL_GPL(l3_write);
90
91
l3_set_clk(struct l3_pins * adap,int val)92 static void l3_set_clk(struct l3_pins *adap, int val)
93 {
94 gpio_set_value(adap->gpio_clk, val);
95 }
96
l3_set_data(struct l3_pins * adap,int val)97 static void l3_set_data(struct l3_pins *adap, int val)
98 {
99 gpio_set_value(adap->gpio_data, val);
100 }
101
l3_set_mode(struct l3_pins * adap,int val)102 static void l3_set_mode(struct l3_pins *adap, int val)
103 {
104 gpio_set_value(adap->gpio_mode, val);
105 }
106
l3_set_gpio_ops(struct device * dev,struct l3_pins * adap)107 int l3_set_gpio_ops(struct device *dev, struct l3_pins *adap)
108 {
109 int ret;
110
111 if (!adap->use_gpios)
112 return -EINVAL;
113
114 ret = devm_gpio_request_one(dev, adap->gpio_data,
115 GPIOF_OUT_INIT_LOW, "l3_data");
116 if (ret < 0)
117 return ret;
118 adap->setdat = l3_set_data;
119
120 ret = devm_gpio_request_one(dev, adap->gpio_clk,
121 GPIOF_OUT_INIT_LOW, "l3_clk");
122 if (ret < 0)
123 return ret;
124 adap->setclk = l3_set_clk;
125
126 ret = devm_gpio_request_one(dev, adap->gpio_mode,
127 GPIOF_OUT_INIT_LOW, "l3_mode");
128 if (ret < 0)
129 return ret;
130 adap->setmode = l3_set_mode;
131
132 return 0;
133 }
134 EXPORT_SYMBOL_GPL(l3_set_gpio_ops);
135
136 MODULE_DESCRIPTION("L3 bit-banging driver");
137 MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
138 MODULE_LICENSE("GPL");
139
