Most of the code is taken (and adapted) from Linux kernel driver. Just add CONFIG_ZYNQ_GPIO to you config to enable it Signed-off-by: Andrea Scian <andrea.scian@dave.eu> Signed-off-by: Michal Simek <michal.simek@xilinx.com>master
Andrea Scian
10 years ago
committed by
Michal Simek
parent
cc555bd4f4
commit
d37c6288a6
@ -0,0 +1,220 @@ |
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/*
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* Xilinx Zynq GPIO device driver |
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* |
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* Copyright (C) 2015 DAVE Embedded Systems <devel@dave.eu> |
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* |
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* Most of code taken from linux kernel driver (linux/drivers/gpio/gpio-zynq.c) |
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* Copyright (C) 2009 - 2014 Xilinx, Inc. |
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* |
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* SPDX-License-Identifier: GPL-2.0+ |
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*/ |
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#include <common.h> |
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#include <asm/gpio.h> |
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#include <asm/io.h> |
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#include <asm/errno.h> |
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/**
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* zynq_gpio_get_bank_pin - Get the bank number and pin number within that bank |
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* for a given pin in the GPIO device |
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* @pin_num: gpio pin number within the device |
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* @bank_num: an output parameter used to return the bank number of the gpio |
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* pin |
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* @bank_pin_num: an output parameter used to return pin number within a bank |
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* for the given gpio pin |
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* |
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* Returns the bank number and pin offset within the bank. |
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*/ |
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static inline void zynq_gpio_get_bank_pin(unsigned int pin_num, |
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unsigned int *bank_num, |
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unsigned int *bank_pin_num) |
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{ |
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switch (pin_num) { |
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case ZYNQ_GPIO_BANK0_PIN_MIN ... ZYNQ_GPIO_BANK0_PIN_MAX: |
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*bank_num = 0; |
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*bank_pin_num = pin_num; |
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break; |
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case ZYNQ_GPIO_BANK1_PIN_MIN ... ZYNQ_GPIO_BANK1_PIN_MAX: |
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*bank_num = 1; |
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*bank_pin_num = pin_num - ZYNQ_GPIO_BANK1_PIN_MIN; |
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break; |
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case ZYNQ_GPIO_BANK2_PIN_MIN ... ZYNQ_GPIO_BANK2_PIN_MAX: |
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*bank_num = 2; |
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*bank_pin_num = pin_num - ZYNQ_GPIO_BANK2_PIN_MIN; |
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break; |
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case ZYNQ_GPIO_BANK3_PIN_MIN ... ZYNQ_GPIO_BANK3_PIN_MAX: |
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*bank_num = 3; |
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*bank_pin_num = pin_num - ZYNQ_GPIO_BANK3_PIN_MIN; |
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break; |
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default: |
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printf("invalid GPIO pin number: %u\n", pin_num); |
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*bank_num = 0; |
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*bank_pin_num = 0; |
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break; |
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} |
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} |
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int gpio_is_valid(unsigned gpio) |
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{ |
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return (gpio >= 0) && (gpio < ZYNQ_GPIO_NR_GPIOS); |
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} |
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static int check_gpio(unsigned gpio) |
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{ |
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if (!gpio_is_valid(gpio)) { |
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printf("ERROR : check_gpio: invalid GPIO %d\n", gpio); |
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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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* gpio_get_value - Get the state of the specified pin of GPIO device |
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* @gpio: gpio pin number within the device |
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* |
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* This function reads the state of the specified pin of the GPIO device. |
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* |
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* Return: 0 if the pin is low, 1 if pin is high. |
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*/ |
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int gpio_get_value(unsigned gpio) |
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{ |
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u32 data; |
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unsigned int bank_num, bank_pin_num; |
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if (check_gpio(gpio) < 0) |
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return -1; |
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zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num); |
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data = readl(ZYNQ_GPIO_BASE_ADDRESS + |
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ZYNQ_GPIO_DATA_RO_OFFSET(bank_num)); |
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return (data >> bank_pin_num) & 1; |
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} |
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/**
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* gpio_set_value - Modify the value of the pin with specified value |
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* @gpio: gpio pin number within the device |
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* @value: value used to modify the value of the specified pin |
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* |
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* This function calculates the register offset (i.e to lower 16 bits or |
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* upper 16 bits) based on the given pin number and sets the value of a |
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* gpio pin to the specified value. The value is either 0 or non-zero. |
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*/ |
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int gpio_set_value(unsigned gpio, int value) |
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{ |
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unsigned int reg_offset, bank_num, bank_pin_num; |
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if (check_gpio(gpio) < 0) |
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return -1; |
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zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num); |
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if (bank_pin_num >= ZYNQ_GPIO_MID_PIN_NUM) { |
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/* only 16 data bits in bit maskable reg */ |
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bank_pin_num -= ZYNQ_GPIO_MID_PIN_NUM; |
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reg_offset = ZYNQ_GPIO_DATA_MSW_OFFSET(bank_num); |
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} else { |
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reg_offset = ZYNQ_GPIO_DATA_LSW_OFFSET(bank_num); |
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} |
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/*
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* get the 32 bit value to be written to the mask/data register where |
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* the upper 16 bits is the mask and lower 16 bits is the data |
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*/ |
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value = !!value; |
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value = ~(1 << (bank_pin_num + ZYNQ_GPIO_MID_PIN_NUM)) & |
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((value << bank_pin_num) | ZYNQ_GPIO_UPPER_MASK); |
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writel(value, ZYNQ_GPIO_BASE_ADDRESS + reg_offset); |
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return 0; |
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} |
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/**
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* gpio_direction_input - Set the direction of the specified GPIO pin as input |
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* @gpio: gpio pin number within the device |
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* |
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* This function uses the read-modify-write sequence to set the direction of |
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* the gpio pin as input. |
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* |
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* Return: -1 if invalid gpio specified, 0 if successul |
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*/ |
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int gpio_direction_input(unsigned gpio) |
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{ |
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u32 reg; |
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unsigned int bank_num, bank_pin_num; |
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if (check_gpio(gpio) < 0) |
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return -1; |
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zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num); |
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/* bank 0 pins 7 and 8 are special and cannot be used as inputs */ |
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if (bank_num == 0 && (bank_pin_num == 7 || bank_pin_num == 8)) |
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return -1; |
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/* clear the bit in direction mode reg to set the pin as input */ |
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reg = readl(ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num)); |
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reg &= ~BIT(bank_pin_num); |
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writel(reg, ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num)); |
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return 0; |
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} |
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/**
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* gpio_direction_output - Set the direction of the specified GPIO pin as output |
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* @gpio: gpio pin number within the device |
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* @value: value to be written to specified pin |
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* |
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* This function sets the direction of specified GPIO pin as output, configures |
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* the Output Enable register for the pin and uses zynq_gpio_set to set |
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* the value of the pin to the value specified. |
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* |
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* Return: 0 always |
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*/ |
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int gpio_direction_output(unsigned gpio, int value) |
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{ |
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u32 reg; |
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unsigned int bank_num, bank_pin_num; |
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if (check_gpio(gpio) < 0) |
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return -1; |
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zynq_gpio_get_bank_pin(gpio, &bank_num, &bank_pin_num); |
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/* set the GPIO pin as output */ |
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reg = readl(ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num)); |
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reg |= BIT(bank_pin_num); |
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writel(reg, ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_DIRM_OFFSET(bank_num)); |
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/* configure the output enable reg for the pin */ |
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reg = readl(ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_OUTEN_OFFSET(bank_num)); |
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reg |= BIT(bank_pin_num); |
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writel(reg, ZYNQ_GPIO_BASE_ADDRESS + ZYNQ_GPIO_OUTEN_OFFSET(bank_num)); |
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/* set the state of the pin */ |
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gpio_set_value(gpio, value); |
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return 0; |
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} |
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/**
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* Request a gpio before using it. |
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* |
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* NOTE: Argument 'label' is unused. |
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*/ |
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int gpio_request(unsigned gpio, const char *label) |
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{ |
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if (check_gpio(gpio) < 0) |
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return -1; |
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return 0; |
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} |
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/**
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* Reset and free the gpio after using it. |
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*/ |
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int gpio_free(unsigned gpio) |
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{ |
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return 0; |
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} |
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