1 // SPDX-License-Identifier: GPL-2.0+
4 * Dirk Eibach, Guntermann & Drunck GmbH, dirk.eibach@gdsys.cc
8 * Driver for NXP's pca9698 40 bit I2C gpio expander
13 #include <linux/errno.h>
17 * The pca9698 registers
20 #define PCA9698_REG_INPUT 0x00
21 #define PCA9698_REG_OUTPUT 0x08
22 #define PCA9698_REG_POLARITY 0x10
23 #define PCA9698_REG_CONFIG 0x18
25 #define PCA9698_BUFFER_SIZE 5
26 #define PCA9698_GPIO_COUNT 40
28 static int pca9698_read40(u8 addr, u8 offset, u8 *buffer)
30 u8 command = offset | 0x80; /* autoincrement */
32 return i2c_read(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
35 static int pca9698_write40(u8 addr, u8 offset, u8 *buffer)
37 u8 command = offset | 0x80; /* autoincrement */
39 return i2c_write(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
42 static void pca9698_set_bit(unsigned gpio, u8 *buffer, unsigned value)
44 unsigned byte = gpio / 8;
45 unsigned bit = gpio % 8;
48 buffer[byte] |= (1 << bit);
50 buffer[byte] &= ~(1 << bit);
53 int pca9698_request(unsigned gpio, const char *label)
55 if (gpio >= PCA9698_GPIO_COUNT)
61 void pca9698_free(unsigned gpio)
65 int pca9698_direction_input(u8 addr, unsigned gpio)
67 u8 data[PCA9698_BUFFER_SIZE];
70 res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
74 pca9698_set_bit(gpio, data, 1);
76 return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
79 int pca9698_direction_output(u8 addr, unsigned gpio, int value)
81 u8 data[PCA9698_BUFFER_SIZE];
84 res = pca9698_set_value(addr, gpio, value);
88 res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
92 pca9698_set_bit(gpio, data, 0);
94 return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
97 int pca9698_get_value(u8 addr, unsigned gpio)
99 unsigned config_byte = gpio / 8;
100 unsigned config_bit = gpio % 8;
102 u8 data[PCA9698_BUFFER_SIZE];
105 res = pca9698_read40(addr, PCA9698_REG_INPUT, data);
109 value = data[config_byte] & (1 << config_bit);
114 int pca9698_set_value(u8 addr, unsigned gpio, int value)
116 u8 data[PCA9698_BUFFER_SIZE];
119 res = pca9698_read40(addr, PCA9698_REG_OUTPUT, data);
123 pca9698_set_bit(gpio, data, value);
125 return pca9698_write40(addr, PCA9698_REG_OUTPUT, data);