1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2011
4 * Dirk Eibach, Guntermann & Drunck GmbH, dirk.eibach@gdsys.cc
5 */
6
7 /*
8 * Driver for NXP's pca9698 40 bit I2C gpio expander
9 */
10
11 #include <common.h>
12 #include <i2c.h>
13 #include <malloc.h>
14 #include <linux/errno.h>
15 #include <pca9698.h>
16
17 /*
18 * The pca9698 registers
19 */
20
21 #define PCA9698_REG_INPUT 0x00
22 #define PCA9698_REG_OUTPUT 0x08
23 #define PCA9698_REG_POLARITY 0x10
24 #define PCA9698_REG_CONFIG 0x18
25
26 #define PCA9698_BUFFER_SIZE 5
27 #define PCA9698_GPIO_COUNT 40
28
pca9698_read40(u8 addr,u8 offset,u8 * buffer)29 static int pca9698_read40(u8 addr, u8 offset, u8 *buffer)
30 {
31 u8 command = offset | 0x80; /* autoincrement */
32
33 return i2c_read(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
34 }
35
pca9698_write40(u8 addr,u8 offset,u8 * buffer)36 static int pca9698_write40(u8 addr, u8 offset, u8 *buffer)
37 {
38 u8 command = offset | 0x80; /* autoincrement */
39
40 return i2c_write(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
41 }
42
pca9698_set_bit(unsigned gpio,u8 * buffer,unsigned value)43 static void pca9698_set_bit(unsigned gpio, u8 *buffer, unsigned value)
44 {
45 unsigned byte = gpio / 8;
46 unsigned bit = gpio % 8;
47
48 if (value)
49 buffer[byte] |= (1 << bit);
50 else
51 buffer[byte] &= ~(1 << bit);
52 }
53
pca9698_request(unsigned gpio,const char * label)54 int pca9698_request(unsigned gpio, const char *label)
55 {
56 if (gpio >= PCA9698_GPIO_COUNT)
57 return -EINVAL;
58
59 return 0;
60 }
61
pca9698_free(unsigned gpio)62 void pca9698_free(unsigned gpio)
63 {
64 }
65
pca9698_direction_input(u8 addr,unsigned gpio)66 int pca9698_direction_input(u8 addr, unsigned gpio)
67 {
68 u8 data[PCA9698_BUFFER_SIZE];
69 int res;
70
71 res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
72 if (res)
73 return res;
74
75 pca9698_set_bit(gpio, data, 1);
76
77 return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
78 }
79
pca9698_direction_output(u8 addr,unsigned gpio,int value)80 int pca9698_direction_output(u8 addr, unsigned gpio, int value)
81 {
82 u8 data[PCA9698_BUFFER_SIZE];
83 int res;
84
85 res = pca9698_set_value(addr, gpio, value);
86 if (res)
87 return res;
88
89 res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
90 if (res)
91 return res;
92
93 pca9698_set_bit(gpio, data, 0);
94
95 return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
96 }
97
pca9698_get_value(u8 addr,unsigned gpio)98 int pca9698_get_value(u8 addr, unsigned gpio)
99 {
100 unsigned config_byte = gpio / 8;
101 unsigned config_bit = gpio % 8;
102 unsigned value;
103 u8 data[PCA9698_BUFFER_SIZE];
104 int res;
105
106 res = pca9698_read40(addr, PCA9698_REG_INPUT, data);
107 if (res)
108 return -1;
109
110 value = data[config_byte] & (1 << config_bit);
111
112 return !!value;
113 }
114
pca9698_set_value(u8 addr,unsigned gpio,int value)115 int pca9698_set_value(u8 addr, unsigned gpio, int value)
116 {
117 u8 data[PCA9698_BUFFER_SIZE];
118 int res;
119
120 res = pca9698_read40(addr, PCA9698_REG_OUTPUT, data);
121 if (res)
122 return res;
123
124 pca9698_set_bit(gpio, data, value);
125
126 return pca9698_write40(addr, PCA9698_REG_OUTPUT, data);
127 }
128