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 
17 static 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 
25 static 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 
33 static 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 
40 void 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