322 lines
7.1 KiB
C
322 lines
7.1 KiB
C
/*
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* LPC32xxGPIO driver
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*
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* (C) Copyright 2014 DENX Software Engineering GmbH
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* Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <asm/io.h>
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#include <asm/arch-lpc32xx/cpu.h>
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#include <asm/arch-lpc32xx/gpio.h>
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#include <asm-generic/gpio.h>
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#include <dm.h>
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/**
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* LPC32xx GPIOs work in banks but are non-homogeneous:
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* - each bank holds a different number of GPIOs
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* - some GPIOs are input/ouput, some input only, some output only;
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* - some GPIOs have different meanings as an input and as an output;
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* - some GPIOs are controlled on a given port and bit index, but
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* read on another one.
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*
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* In order to keep this code simple, GPIOS are considered here as
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* homogeneous and linear, from 0 to 159.
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*
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* ** WARNING #1 **
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*
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* Client code is responsible for properly using valid GPIO numbers,
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* including cases where a single physical GPIO has differing numbers
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* for setting its direction, reading it and/or writing to it.
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*
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* ** WARNING #2 **
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*
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* Please read NOTE in description of lpc32xx_gpio_get_function().
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*/
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#define LPC32XX_GPIOS 160
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struct lpc32xx_gpio_priv {
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struct gpio_regs *regs;
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/* GPIO FUNCTION: SEE WARNING #2 */
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signed char function[LPC32XX_GPIOS];
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};
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/**
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* We have 4 GPIO ports of 32 bits each
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*
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* Port mapping offset (32 bits each):
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* - Port 0: 0
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* - Port 1: 32
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* - Port 2: 64
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* - Port 3: GPO / GPIO (output): 96
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* - Port 3: GPI: 128
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*/
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#define MAX_GPIO 160
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#define GPIO_TO_PORT(gpio) ((gpio / 32) & 7)
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#define GPIO_TO_RANK(gpio) (gpio % 32)
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#define GPIO_TO_MASK(gpio) (1 << (gpio % 32))
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/**
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* Configure a GPIO number 'offset' as input
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*/
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static int lpc32xx_gpio_direction_input(struct udevice *dev, unsigned offset)
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{
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int port, mask;
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struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
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struct gpio_regs *regs = gpio_priv->regs;
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port = GPIO_TO_PORT(offset);
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mask = GPIO_TO_MASK(offset);
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switch (port) {
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case 0:
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writel(mask, ®s->p0_dir_clr);
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break;
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case 1:
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writel(mask, ®s->p1_dir_clr);
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break;
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case 2:
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/* ports 2 and 3 share a common direction */
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writel(mask, ®s->p2_p3_dir_clr);
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break;
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case 3:
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/* Setup direction only for GPIO_xx. */
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if ((mask >= 25) && (mask <= 30))
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writel(mask, ®s->p2_p3_dir_clr);
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break;
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case 4:
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/* GPI_xx; nothing to do. */
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break;
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default:
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return -1;
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}
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/* GPIO FUNCTION: SEE WARNING #2 */
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gpio_priv->function[offset] = GPIOF_INPUT;
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return 0;
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}
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/**
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* Get the value of a GPIO
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*/
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static int lpc32xx_gpio_get_value(struct udevice *dev, unsigned offset)
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{
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int port, rank, mask, value;
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struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
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struct gpio_regs *regs = gpio_priv->regs;
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port = GPIO_TO_PORT(offset);
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switch (port) {
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case 0:
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value = readl(®s->p0_inp_state);
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break;
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case 1:
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value = readl(®s->p1_inp_state);
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break;
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case 2:
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value = readl(®s->p2_inp_state);
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break;
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case 3:
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/* Read GPO_xx and GPIO_xx (as output) using p3_outp_state. */
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value = readl(®s->p3_outp_state);
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break;
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case 4:
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/* Read GPI_xx and GPIO_xx (as input) using p3_inp_state. */
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value = readl(®s->p3_inp_state);
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break;
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default:
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return -1;
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}
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rank = GPIO_TO_RANK(offset);
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mask = GPIO_TO_MASK(offset);
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return (value & mask) >> rank;
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}
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/**
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* Set a GPIO
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*/
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static int gpio_set(struct udevice *dev, unsigned gpio)
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{
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int port, mask;
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struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
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struct gpio_regs *regs = gpio_priv->regs;
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port = GPIO_TO_PORT(gpio);
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mask = GPIO_TO_MASK(gpio);
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switch (port) {
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case 0:
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writel(mask, ®s->p0_outp_set);
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break;
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case 1:
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writel(mask, ®s->p1_outp_set);
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break;
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case 2:
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writel(mask, ®s->p2_outp_set);
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break;
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case 3:
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writel(mask, ®s->p3_outp_set);
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break;
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case 4:
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/* GPI_xx; invalid. */
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default:
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return -1;
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}
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return 0;
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}
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/**
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* Clear a GPIO
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*/
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static int gpio_clr(struct udevice *dev, unsigned gpio)
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{
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int port, mask;
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struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
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struct gpio_regs *regs = gpio_priv->regs;
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port = GPIO_TO_PORT(gpio);
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mask = GPIO_TO_MASK(gpio);
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switch (port) {
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case 0:
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writel(mask, ®s->p0_outp_clr);
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break;
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case 1:
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writel(mask, ®s->p1_outp_clr);
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break;
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case 2:
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writel(mask, ®s->p2_outp_clr);
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break;
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case 3:
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writel(mask, ®s->p3_outp_clr);
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break;
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case 4:
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/* GPI_xx; invalid. */
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default:
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return -1;
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}
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return 0;
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}
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/**
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* Set the value of a GPIO
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*/
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static int lpc32xx_gpio_set_value(struct udevice *dev, unsigned offset,
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int value)
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{
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if (value)
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return gpio_set(dev, offset);
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else
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return gpio_clr(dev, offset);
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}
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/**
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* Configure a GPIO number 'offset' as output with given initial value.
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*/
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static int lpc32xx_gpio_direction_output(struct udevice *dev, unsigned offset,
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int value)
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{
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int port, mask;
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struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
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struct gpio_regs *regs = gpio_priv->regs;
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port = GPIO_TO_PORT(offset);
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mask = GPIO_TO_MASK(offset);
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switch (port) {
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case 0:
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writel(mask, ®s->p0_dir_set);
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break;
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case 1:
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writel(mask, ®s->p1_dir_set);
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break;
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case 2:
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/* ports 2 and 3 share a common direction */
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writel(mask, ®s->p2_p3_dir_set);
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break;
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case 3:
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/* Setup direction only for GPIO_xx. */
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if ((mask >= 25) && (mask <= 30))
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writel(mask, ®s->p2_p3_dir_set);
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break;
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case 4:
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/* GPI_xx; invalid. */
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default:
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return -1;
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}
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/* GPIO FUNCTION: SEE WARNING #2 */
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gpio_priv->function[offset] = GPIOF_OUTPUT;
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return lpc32xx_gpio_set_value(dev, offset, value);
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}
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/**
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* GPIO functions are supposed to be computed from their current
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* configuration, but that's way too complicated in LPC32XX. A simpler
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* approach is used, where the GPIO functions are cached in an array.
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* When the GPIO is in use, its function is either "input" or "output"
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* depending on its direction, otherwise its function is "unknown".
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*
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* ** NOTE **
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*
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* THIS APPROACH WAS CHOSEN DU TO THE COMPLEX NATURE OF THE LPC32XX
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* GPIOS; DO NOT TAKE THIS AS AN EXAMPLE FOR NEW CODE.
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*/
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static int lpc32xx_gpio_get_function(struct udevice *dev, unsigned offset)
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{
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struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
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return gpio_priv->function[offset];
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}
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static const struct dm_gpio_ops gpio_lpc32xx_ops = {
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.direction_input = lpc32xx_gpio_direction_input,
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.direction_output = lpc32xx_gpio_direction_output,
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.get_value = lpc32xx_gpio_get_value,
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.set_value = lpc32xx_gpio_set_value,
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.get_function = lpc32xx_gpio_get_function,
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};
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static int lpc32xx_gpio_probe(struct udevice *dev)
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{
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struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
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struct gpio_dev_priv *uc_priv = dev->uclass_priv;
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if (dev->of_offset == -1) {
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/* Tell the uclass how many GPIOs we have */
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uc_priv->gpio_count = LPC32XX_GPIOS;
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}
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/* set base address for GPIO registers */
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gpio_priv->regs = (struct gpio_regs *)GPIO_BASE;
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/* all GPIO functions are unknown until requested */
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/* GPIO FUNCTION: SEE WARNING #2 */
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memset(gpio_priv->function, GPIOF_UNKNOWN, sizeof(gpio_priv->function));
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return 0;
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}
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U_BOOT_DRIVER(gpio_lpc32xx) = {
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.name = "gpio_lpc32xx",
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.id = UCLASS_GPIO,
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.ops = &gpio_lpc32xx_ops,
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.probe = lpc32xx_gpio_probe,
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.priv_auto_alloc_size = sizeof(struct lpc32xx_gpio_priv),
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};
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