u-boot/drivers/gpio/lpc32xx_gpio.c

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/*
* LPC32xxGPIO driver
*
* (C) Copyright 2014 DENX Software Engineering GmbH
* Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <asm/io.h>
#include <asm/arch-lpc32xx/cpu.h>
#include <asm/arch-lpc32xx/gpio.h>
#include <asm-generic/gpio.h>
#include <dm.h>
/**
* LPC32xx GPIOs work in banks but are non-homogeneous:
* - each bank holds a different number of GPIOs
* - some GPIOs are input/ouput, some input only, some output only;
* - some GPIOs have different meanings as an input and as an output;
* - some GPIOs are controlled on a given port and bit index, but
* read on another one.
*
* In order to keep this code simple, GPIOS are considered here as
* homogeneous and linear, from 0 to 127.
*
* ** WARNING #1 **
*
* Client code is responsible for properly using valid GPIO numbers,
* including cases where a single physical GPIO has differing numbers
* for setting its direction, reading it and/or writing to it.
*
* ** WARNING #2 **
*
* Please read NOTE in description of lpc32xx_gpio_get_function().
*/
#define LPC32XX_GPIOS 128
struct lpc32xx_gpio_priv {
struct gpio_regs *regs;
/* GPIO FUNCTION: SEE WARNING #2 */
signed char function[LPC32XX_GPIOS];
};
/**
* We have 4 GPIO ports of 32 bits each
*/
#define MAX_GPIO 128
#define GPIO_TO_PORT(gpio) ((gpio / 32) & 3)
#define GPIO_TO_RANK(gpio) (gpio % 32)
#define GPIO_TO_MASK(gpio) (1 << (gpio % 32))
/**
* Configure a GPIO number 'offset' as input
*/
static int lpc32xx_gpio_direction_input(struct udevice *dev, unsigned offset)
{
int port, mask;
struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
struct gpio_regs *regs = gpio_priv->regs;
port = GPIO_TO_PORT(offset);
mask = GPIO_TO_MASK(offset);
switch (port) {
case 0:
writel(mask, &regs->p0_dir_clr);
break;
case 1:
writel(mask, &regs->p1_dir_clr);
break;
case 2:
/* ports 2 and 3 share a common direction */
case 3:
writel(mask, &regs->p2_p3_dir_clr);
break;
default:
return -1;
}
/* GPIO FUNCTION: SEE WARNING #2 */
gpio_priv->function[offset] = GPIOF_INPUT;
return 0;
}
/**
* Get the value of a GPIO
*/
static int lpc32xx_gpio_get_value(struct udevice *dev, unsigned offset)
{
int port, rank, mask, value;
struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
struct gpio_regs *regs = gpio_priv->regs;
port = GPIO_TO_PORT(offset);
switch (port) {
case 0:
value = readl(&regs->p0_inp_state);
break;
case 1:
value = readl(&regs->p1_inp_state);
break;
case 2:
value = readl(&regs->p2_inp_state);
break;
case 3:
value = readl(&regs->p3_inp_state);
break;
default:
return -1;
}
rank = GPIO_TO_RANK(offset);
mask = GPIO_TO_MASK(offset);
return (value & mask) >> rank;
}
/**
* Set a GPIO
*/
static int gpio_set(struct udevice *dev, unsigned gpio)
{
int port, mask;
struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
struct gpio_regs *regs = gpio_priv->regs;
port = GPIO_TO_PORT(gpio);
mask = GPIO_TO_MASK(gpio);
switch (port) {
case 0:
writel(mask, &regs->p0_outp_set);
break;
case 1:
writel(mask, &regs->p1_outp_set);
break;
case 2:
writel(mask, &regs->p2_outp_set);
break;
case 3:
writel(mask, &regs->p3_outp_set);
break;
default:
return -1;
}
return 0;
}
/**
* Clear a GPIO
*/
static int gpio_clr(struct udevice *dev, unsigned gpio)
{
int port, mask;
struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
struct gpio_regs *regs = gpio_priv->regs;
port = GPIO_TO_PORT(gpio);
mask = GPIO_TO_MASK(gpio);
switch (port) {
case 0:
writel(mask, &regs->p0_outp_clr);
break;
case 1:
writel(mask, &regs->p1_outp_clr);
break;
case 2:
writel(mask, &regs->p2_outp_clr);
break;
case 3:
writel(mask, &regs->p3_outp_clr);
break;
default:
return -1;
}
return 0;
}
/**
* Set the value of a GPIO
*/
static int lpc32xx_gpio_set_value(struct udevice *dev, unsigned offset,
int value)
{
if (value)
return gpio_set(dev, offset);
else
return gpio_clr(dev, offset);
}
/**
* Configure a GPIO number 'offset' as output with given initial value.
*/
static int lpc32xx_gpio_direction_output(struct udevice *dev, unsigned offset,
int value)
{
int port, mask;
struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
struct gpio_regs *regs = gpio_priv->regs;
port = GPIO_TO_PORT(offset);
mask = GPIO_TO_MASK(offset);
switch (port) {
case 0:
writel(mask, &regs->p0_dir_set);
break;
case 1:
writel(mask, &regs->p1_dir_set);
break;
case 2:
/* ports 2 and 3 share a common direction */
case 3:
writel(mask, &regs->p2_p3_dir_set);
break;
default:
return -1;
}
/* GPIO FUNCTION: SEE WARNING #2 */
gpio_priv->function[offset] = GPIOF_OUTPUT;
return lpc32xx_gpio_set_value(dev, offset, value);
}
/**
* GPIO functions are supposed to be computed from their current
* configuration, but that's way too complicated in LPC32XX. A simpler
* approach is used, where the GPIO functions are cached in an array.
* When the GPIO is in use, its function is either "input" or "output"
* depending on its direction, otherwise its function is "unknown".
*
* ** NOTE **
*
* THIS APPROACH WAS CHOSEN DU TO THE COMPLEX NATURE OF THE LPC32XX
* GPIOS; DO NOT TAKE THIS AS AN EXAMPLE FOR NEW CODE.
*/
static int lpc32xx_gpio_get_function(struct udevice *dev, unsigned offset)
{
struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
return gpio_priv->function[offset];
}
static const struct dm_gpio_ops gpio_lpc32xx_ops = {
.direction_input = lpc32xx_gpio_direction_input,
.direction_output = lpc32xx_gpio_direction_output,
.get_value = lpc32xx_gpio_get_value,
.set_value = lpc32xx_gpio_set_value,
.get_function = lpc32xx_gpio_get_function,
};
static int lpc32xx_gpio_probe(struct udevice *dev)
{
struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
struct gpio_dev_priv *uc_priv = dev->uclass_priv;
if (dev->of_offset == -1) {
/* Tell the uclass how many GPIOs we have */
uc_priv->gpio_count = LPC32XX_GPIOS;
}
/* set base address for GPIO registers */
gpio_priv->regs = (struct gpio_regs *)GPIO_BASE;
/* all GPIO functions are unknown until requested */
/* GPIO FUNCTION: SEE WARNING #2 */
memset(gpio_priv->function, GPIOF_UNKNOWN, sizeof(gpio_priv->function));
return 0;
}
U_BOOT_DRIVER(gpio_lpc32xx) = {
.name = "gpio_lpc32xx",
.id = UCLASS_GPIO,
.ops = &gpio_lpc32xx_ops,
.probe = lpc32xx_gpio_probe,
.priv_auto_alloc_size = sizeof(struct lpc32xx_gpio_priv),
};