LXR uboot/board/LaCie/common/cpld-gpio-bus.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * cpld-gpio-bus.c: provides support for the CPLD GPIO bus found on some LaCie
   4 * boards (as the 2Big/5Big Network v2 and the 2Big NAS). This parallel GPIO
   5 * bus exposes two registers (address and data). Each of this register is made
   6 * up of several dedicated GPIOs. An extra GPIO is used to notify the CPLD that
   7 * the registers have been updated.
   8 *
   9 * Mostly this bus is used to configure the LEDs on LaCie boards.
  10 *
  11 * Copyright (C) 2013 Simon Guinot <simon.guinot@sequanux.org>
  12 */
  13
  14#include <asm/arch/gpio.h>
  15#include "cpld-gpio-bus.h"
  16
  17static void cpld_gpio_bus_set_addr(struct cpld_gpio_bus *bus, unsigned addr)
  18{
  19        int pin;
  20
  21        for (pin = 0; pin < bus->num_addr; pin++)
  22                kw_gpio_set_value(bus->addr[pin], (addr >> pin) & 1);
  23}
  24
  25static void cpld_gpio_bus_set_data(struct cpld_gpio_bus *bus, unsigned data)
  26{
  27        int pin;
  28
  29        for (pin = 0; pin < bus->num_data; pin++)
  30                kw_gpio_set_value(bus->data[pin], (data >> pin) & 1);
  31}
  32
  33static void cpld_gpio_bus_enable_select(struct cpld_gpio_bus *bus)
  34{
  35        /* The transfer is enabled on the raising edge. */
  36        kw_gpio_set_value(bus->enable, 0);
  37        kw_gpio_set_value(bus->enable, 1);
  38}
  39
  40void cpld_gpio_bus_write(struct cpld_gpio_bus *bus,
  41                         unsigned addr, unsigned value)
  42{
  43        cpld_gpio_bus_set_addr(bus, addr);
  44        cpld_gpio_bus_set_data(bus, value);
  45        cpld_gpio_bus_enable_select(bus);
  46}
  47