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