1 /*
2  * cpld-gpio-bus.c: provides support for the CPLD GPIO bus found on some LaCie
3  * boards (as the 2Big/5Big Network v2 and the 2Big NAS). This parallel GPIO
4  * bus exposes two registers (address and data). Each of this register is made
5  * up of several dedicated GPIOs. An extra GPIO is used to notify the CPLD that
6  * the registers have been updated.
7  *
8  * Mostly this bus is used to configure the LEDs on LaCie boards.
9  *
10  * Copyright (C) 2013 Simon Guinot <simon.guinot@sequanux.org>
11  *
12  * SPDX-License-Identifier:	GPL-2.0+
13  */
14 
15 #include <asm/arch/gpio.h>
16 #include "cpld-gpio-bus.h"
17 
18 static void cpld_gpio_bus_set_addr(struct cpld_gpio_bus *bus, unsigned addr)
19 {
20 	int pin;
21 
22 	for (pin = 0; pin < bus->num_addr; pin++)
23 		kw_gpio_set_value(bus->addr[pin], (addr >> pin) & 1);
24 }
25 
26 static void cpld_gpio_bus_set_data(struct cpld_gpio_bus *bus, unsigned data)
27 {
28 	int pin;
29 
30 	for (pin = 0; pin < bus->num_data; pin++)
31 		kw_gpio_set_value(bus->data[pin], (data >> pin) & 1);
32 }
33 
34 static void cpld_gpio_bus_enable_select(struct cpld_gpio_bus *bus)
35 {
36 	/* The transfer is enabled on the raising edge. */
37 	kw_gpio_set_value(bus->enable, 0);
38 	kw_gpio_set_value(bus->enable, 1);
39 }
40 
41 void cpld_gpio_bus_write(struct cpld_gpio_bus *bus,
42 			 unsigned addr, unsigned value)
43 {
44 	cpld_gpio_bus_set_addr(bus, addr);
45 	cpld_gpio_bus_set_data(bus, value);
46 	cpld_gpio_bus_enable_select(bus);
47 }
48