drivers/gpio/pca9698.c

   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
  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
  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
  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
  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
  61 void pca9698_free(unsigned gpio)
  62 {
  63 }
  64
  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
  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
  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
 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 }