cpld-gpio-bus.c 1.3 KB

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  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. #include <asm/arch/gpio.h>
  14. #include "cpld-gpio-bus.h"
  15. static void cpld_gpio_bus_set_addr(struct cpld_gpio_bus *bus, unsigned addr)
  16. {
  17. int pin;
  18. for (pin = 0; pin < bus->num_addr; pin++)
  19. kw_gpio_set_value(bus->addr[pin], (addr >> pin) & 1);
  20. }
  21. static void cpld_gpio_bus_set_data(struct cpld_gpio_bus *bus, unsigned data)
  22. {
  23. int pin;
  24. for (pin = 0; pin < bus->num_data; pin++)
  25. kw_gpio_set_value(bus->data[pin], (data >> pin) & 1);
  26. }
  27. static void cpld_gpio_bus_enable_select(struct cpld_gpio_bus *bus)
  28. {
  29. /* The transfer is enabled on the raising edge. */
  30. kw_gpio_set_value(bus->enable, 0);
  31. kw_gpio_set_value(bus->enable, 1);
  32. }
  33. void cpld_gpio_bus_write(struct cpld_gpio_bus *bus,
  34. unsigned addr, unsigned value)
  35. {
  36. cpld_gpio_bus_set_addr(bus, addr);
  37. cpld_gpio_bus_set_data(bus, value);
  38. cpld_gpio_bus_enable_select(bus);
  39. }