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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2013 Alexandru Gagniuc <mr.nuke.me@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*
* Helpers to multiplex and configure pins on Allwinner SoCs
*
*/
#include "gpio.h"
#include <device/mmio.h>
static struct a10_gpio *const gpio = (void *)GPIO_BASE;
/**
* \brief Set the pad function of a single pin
*
* @param[in] port GPIO port of the pin (GPA -> GPS)
* @param[in] pin the pin number in the given port (1 -> 31)
* @param[in] pad_func The peripheral function to which to connect this pin
*/
void gpio_set_pin_func(u8 port, u8 pin, u8 pad_func)
{
u8 reg, bit;
u32 reg32;
if ((port > GPS))
return;
pin &= 0x1f;
reg = pin / 8;
bit = (pin % 8) * 4;
reg32 = read32(&gpio->port[port].cfg[reg]);
reg32 &= ~(0xf << bit);
reg32 |= (pad_func & 0xf) << bit;
write32(&gpio->port[port].cfg[reg], reg32);
}
/**
* \brief Set the pad function of a group of pins
*
* Multiplex a group of pins to the same pad function. This is useful for
* peripherals that use the same function number for several pins. This function
* allows those pins to be set with a single call.
*
* Example:
* gpio_set_multipin_func(GPB, (1 << 23) | (1 << 22), 2);
*
* @param[in] port GPIO port of the pin (GPA -> GPS)
* @param[in] pin_mask 32-bit mask indicating which pins to re-multiplex. For
* each set bit, the corresponding pin will be multiplexed.
* @param[in] pad_func The peripheral function to which to connect the pins
*/
void gpio_set_multipin_func(u8 port, u32 pin_mask, u8 pad_func)
{
int j;
u8 reg, bit;
u32 reg32, mask_offset;
if ((port > GPS))
return;
for (reg = 0; reg < 4; reg++) {
mask_offset = 8 * reg;
/* Don't run the inner loop if we're not touching any pins */
if (!(pin_mask & (0xff << mask_offset)))
continue;
reg32 = read32(&gpio->port[port].cfg[reg]);
for (j = 0; j < 8; j++) {
if (!(pin_mask & (1 << (j + mask_offset))))
continue;
bit = j * 4;
reg32 &= ~(0xf << bit);
reg32 |= (pad_func & 0xf) << bit;
}
write32(&gpio->port[port].cfg[reg], reg32);
}
}
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