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bootloader/u-boot_2015_04/drivers/gpio/pca9698.c 2.39 KB
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  /*
   * (C) Copyright 2011
   * Dirk Eibach,  Guntermann & Drunck GmbH, eibach@gdsys.de
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  /*
   * Driver for NXP's pca9698 40 bit I2C gpio expander
   */
  
  #include <common.h>
  #include <i2c.h>
  #include <asm/errno.h>
  #include <pca9698.h>
  
  /*
   * The pca9698 registers
   */
  
  #define PCA9698_REG_INPUT		0x00
  #define PCA9698_REG_OUTPUT		0x08
  #define PCA9698_REG_POLARITY		0x10
  #define PCA9698_REG_CONFIG		0x18
  
  #define PCA9698_BUFFER_SIZE		5
  #define PCA9698_GPIO_COUNT		40
  
  static int pca9698_read40(u8 addr, u8 offset, u8 *buffer)
  {
  	u8 command = offset | 0x80;  /* autoincrement */
  
  	return i2c_read(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
  }
  
  static int pca9698_write40(u8 addr, u8 offset, u8 *buffer)
  {
  	u8 command = offset | 0x80;  /* autoincrement */
  
  	return i2c_write(addr, command, 1, buffer, PCA9698_BUFFER_SIZE);
  }
  
  static void pca9698_set_bit(unsigned gpio, u8 *buffer, unsigned value)
  {
  	unsigned byte = gpio / 8;
  	unsigned bit = gpio % 8;
  
  	if (value)
  		buffer[byte] |= (1 << bit);
  	else
  		buffer[byte] &= ~(1 << bit);
  }
  
  int pca9698_request(unsigned gpio, const char *label)
  {
  	if (gpio >= PCA9698_GPIO_COUNT)
  		return -EINVAL;
  
  	return 0;
  }
  
  void pca9698_free(unsigned gpio)
  {
  }
  
  int pca9698_direction_input(u8 addr, unsigned gpio)
  {
  	u8 data[PCA9698_BUFFER_SIZE];
  	int res;
  
  	res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
  	if (res)
  		return res;
  
  	pca9698_set_bit(gpio, data, 1);
  
  	return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
  }
  
  int pca9698_direction_output(u8 addr, unsigned gpio, int value)
  {
  	u8 data[PCA9698_BUFFER_SIZE];
  	int res;
  
  	res = pca9698_set_value(addr, gpio, value);
  	if (res)
  		return res;
  
  	res = pca9698_read40(addr, PCA9698_REG_CONFIG, data);
  	if (res)
  		return res;
  
  	pca9698_set_bit(gpio, data, 0);
  
  	return pca9698_write40(addr, PCA9698_REG_CONFIG, data);
  }
  
  int pca9698_get_value(u8 addr, unsigned gpio)
  {
  	unsigned config_byte = gpio / 8;
  	unsigned config_bit = gpio % 8;
  	unsigned value;
  	u8 data[PCA9698_BUFFER_SIZE];
  	int res;
  
  	res = pca9698_read40(addr, PCA9698_REG_INPUT, data);
  	if (res)
  		return -1;
  
  	value = data[config_byte] & (1 << config_bit);
  
  	return !!value;
  }
  
  int pca9698_set_value(u8 addr, unsigned gpio, int value)
  {
  	u8 data[PCA9698_BUFFER_SIZE];
  	int res;
  
  	res = pca9698_read40(addr, PCA9698_REG_OUTPUT, data);
  	if (res)
  		return res;
  
  	pca9698_set_bit(gpio, data, value);
  
  	return pca9698_write40(addr, PCA9698_REG_OUTPUT, data);
  }