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