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/* Copyright 2014 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/*
* GPIO module for Chrome EC
*
* These functions are shared by the STM32F0 and STM32L variants.
*/
#include "builtin/assert.h"
#include "common.h"
#include "gpio_chip.h"
#include "registers.h"
#include "util.h"
static uint32_t expand_to_2bit_mask(uint32_t mask)
{
uint32_t mask_out = 0;
while (mask) {
int bit = get_next_bit(&mask);
mask_out |= 3 << (bit * 2);
}
return mask_out;
}
int gpio_get_flags_by_mask(uint32_t port, uint32_t mask)
{
uint32_t flags = 0;
uint32_t val = 0;
const uint32_t mask2 = expand_to_2bit_mask(mask);
/* Only one bit must be set. */
if ((mask != (mask & -mask)) || (mask == 0))
return 0;
/* Check output type. */
val = STM32_GPIO_PUPDR(port) & mask2;
if (val == (0x55555555 & mask2))
flags |= GPIO_PULL_UP;
if (val == (0xaaaaaaaa & mask2))
flags |= GPIO_PULL_DOWN;
if (STM32_GPIO_OTYPER(port) & mask)
flags |= GPIO_OPEN_DRAIN;
/* Check mode. */
val = STM32_GPIO_MODER(port) & mask2;
if (val == (0x55555555 & mask2))
flags |= GPIO_OUTPUT;
if (val == (0xFFFFFFFF & mask2))
flags |= GPIO_ANALOG;
if (val == (0x0 & mask2))
flags |= GPIO_INPUT;
if (val == (0xaaaaaaaa & mask2))
flags |= GPIO_ALTERNATE;
if (flags & GPIO_OUTPUT) {
if (STM32_GPIO_ODR(port) & mask)
flags |= GPIO_HIGH;
else
flags |= GPIO_LOW;
}
if (STM32_EXTI_RTSR & mask)
flags |= GPIO_INT_F_RISING;
if (STM32_EXTI_RTSR & mask)
flags |= GPIO_INT_F_RISING;
return flags;
}
void gpio_set_flags_by_mask(uint32_t port, uint32_t mask, uint32_t flags)
{
/* Bitmask for registers with 2 bits per GPIO pin */
const uint32_t mask2 = expand_to_2bit_mask(mask);
uint32_t val;
/* Set up pullup / pulldown */
val = STM32_GPIO_PUPDR(port) & ~mask2;
if (flags & GPIO_PULL_UP)
val |= 0x55555555 & mask2; /* Pull Up = 01 */
else if (flags & GPIO_PULL_DOWN)
val |= 0xaaaaaaaa & mask2; /* Pull Down = 10 */
STM32_GPIO_PUPDR(port) = val;
/*
* Select open drain first, so that we don't glitch the signal when
* changing the line to an output.
*/
if (flags & GPIO_OPEN_DRAIN)
STM32_GPIO_OTYPER(port) |= mask;
else
STM32_GPIO_OTYPER(port) &= ~mask;
val = STM32_GPIO_MODER(port) & ~mask2;
if (flags & GPIO_OUTPUT) {
/*
* Set pin level first to avoid glitching. This is harmless on
* STM32L because the set/reset register isn't connected to the
* output drivers until the pin is made an output.
*/
if (flags & GPIO_HIGH)
STM32_GPIO_BSRR(port) = mask;
else if (flags & GPIO_LOW)
STM32_GPIO_BSRR(port) = mask << 16;
/* General purpose, MODE = 01 */
val |= 0x55555555 & mask2;
STM32_GPIO_MODER(port) = val;
} else if (flags & GPIO_ANALOG) {
/* Analog, MODE=11 */
val |= 0xFFFFFFFF & mask2;
STM32_GPIO_MODER(port) = val;
} else if (flags & GPIO_INPUT) {
/* Input, MODE=00 */
STM32_GPIO_MODER(port) = val;
} else if (flags & GPIO_ALTERNATE) {
/* Alternate, MODE=10 */
val |= 0xaaaaaaaa & mask2;
STM32_GPIO_MODER(port) = val;
}
/* Set up interrupts if necessary */
ASSERT(!(flags & (GPIO_INT_F_LOW | GPIO_INT_F_HIGH)));
if (flags & GPIO_INT_F_RISING)
STM32_EXTI_RTSR |= mask;
if (flags & GPIO_INT_F_FALLING)
STM32_EXTI_FTSR |= mask;
/* Interrupt is enabled by gpio_enable_interrupt() */
}
void gpio_set_alternate_function(uint32_t port, uint32_t mask,
enum gpio_alternate_func func)
{
/* Ensure that the func parameter isn't overflowed */
BUILD_ASSERT((int)MODULE_COUNT <= (int)GPIO_ALT_FUNC_MAX);
int bit;
uint32_t half;
uint32_t afr;
uint32_t moder = STM32_GPIO_MODER(port);
if (func == GPIO_ALT_FUNC_NONE) {
/* Return to normal GPIO function, defaulting to input. */
while (mask) {
bit = get_next_bit(&mask);
moder &= ~(0x3 << (bit * 2));
}
STM32_GPIO_MODER(port) = moder;
return;
}
/* Low half of the GPIO bank */
half = mask & 0xff;
afr = STM32_GPIO_AFRL(port);
while (half) {
bit = get_next_bit(&half);
afr &= ~(0xf << (bit * 4));
afr |= func << (bit * 4);
moder &= ~(0x3 << (bit * 2 + 0));
moder |= 0x2 << (bit * 2 + 0);
}
STM32_GPIO_AFRL(port) = afr;
/* High half of the GPIO bank */
half = (mask >> 8) & 0xff;
afr = STM32_GPIO_AFRH(port);
while (half) {
bit = get_next_bit(&half);
afr &= ~(0xf << (bit * 4));
afr |= func << (bit * 4);
moder &= ~(0x3 << (bit * 2 + 16));
moder |= 0x2 << (bit * 2 + 16);
}
STM32_GPIO_AFRH(port) = afr;
STM32_GPIO_MODER(port) = moder;
}
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