drivers/gpio/pca9698.c

   1 /*
   2  * (C) Copyright 2011
   3  * Dirk Eibach,  Guntermann & Drunck GmbH, eibach@gdsys.de
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * Driver for NXP's pca9698 40 bit I2C gpio expander
  10  */
  11
  12 #include <common.h>
  13 #include <i2c.h>
  14 #include <asm/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
  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
  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
  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
  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
  62 void pca9698_free(unsigned gpio)
  63 {
  64 }
  65
  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
  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
  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
 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 }