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2be0017392
The gpio include file and the gpio documentation declare and document GPIOF_ACTIVE_LOW as one of the flags to be passed to gpio_request_one and related functions. However, the flag is not evaluated or used. This can cause problems in at least two areas: First, the same API can be used to auto-export pins to user space. The missing support for GPIOF_ACTIVE_LOW results in unexpected behavior for such auto-exported pins. Second, the requested gpio pin can be convered for use by gpiod functions with gpio_to_desc(). While gpio API functions do not support GPIOF_ACTIVE_LOW, gpiod functions do, which again results in unexpected behavior. Check the flag in gpio_request_one and set the gpio internal flag FLAG_ACTIVE_LOW if it is set to address those problems. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
115 lines
2.4 KiB
C
115 lines
2.4 KiB
C
#include <linux/gpio/consumer.h>
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#include <linux/gpio/driver.h>
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#include <linux/gpio.h>
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#include "gpiolib.h"
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void gpio_free(unsigned gpio)
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{
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gpiod_free(gpio_to_desc(gpio));
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}
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EXPORT_SYMBOL_GPL(gpio_free);
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/**
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* gpio_request_one - request a single GPIO with initial configuration
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* @gpio: the GPIO number
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* @flags: GPIO configuration as specified by GPIOF_*
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* @label: a literal description string of this GPIO
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*/
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int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
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{
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struct gpio_desc *desc;
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int err;
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desc = gpio_to_desc(gpio);
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err = gpiod_request(desc, label);
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if (err)
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return err;
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if (flags & GPIOF_OPEN_DRAIN)
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set_bit(FLAG_OPEN_DRAIN, &desc->flags);
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if (flags & GPIOF_OPEN_SOURCE)
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set_bit(FLAG_OPEN_SOURCE, &desc->flags);
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if (flags & GPIOF_ACTIVE_LOW)
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set_bit(FLAG_ACTIVE_LOW, &desc->flags);
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if (flags & GPIOF_DIR_IN)
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err = gpiod_direction_input(desc);
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else
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err = gpiod_direction_output_raw(desc,
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(flags & GPIOF_INIT_HIGH) ? 1 : 0);
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if (err)
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goto free_gpio;
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if (flags & GPIOF_EXPORT) {
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err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
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if (err)
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goto free_gpio;
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}
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return 0;
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free_gpio:
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gpiod_free(desc);
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return err;
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}
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EXPORT_SYMBOL_GPL(gpio_request_one);
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int gpio_request(unsigned gpio, const char *label)
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{
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return gpiod_request(gpio_to_desc(gpio), label);
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}
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EXPORT_SYMBOL_GPL(gpio_request);
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/**
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* gpio_request_array - request multiple GPIOs in a single call
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* @array: array of the 'struct gpio'
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* @num: how many GPIOs in the array
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*/
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int gpio_request_array(const struct gpio *array, size_t num)
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{
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int i, err;
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for (i = 0; i < num; i++, array++) {
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err = gpio_request_one(array->gpio, array->flags, array->label);
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if (err)
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goto err_free;
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}
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return 0;
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err_free:
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while (i--)
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gpio_free((--array)->gpio);
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return err;
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}
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EXPORT_SYMBOL_GPL(gpio_request_array);
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/**
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* gpio_free_array - release multiple GPIOs in a single call
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* @array: array of the 'struct gpio'
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* @num: how many GPIOs in the array
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*/
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void gpio_free_array(const struct gpio *array, size_t num)
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{
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while (num--)
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gpio_free((array++)->gpio);
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}
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EXPORT_SYMBOL_GPL(gpio_free_array);
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int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
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{
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return gpiod_lock_as_irq(gpiochip_get_desc(chip, offset));
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}
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EXPORT_SYMBOL_GPL(gpio_lock_as_irq);
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void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
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{
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return gpiod_unlock_as_irq(gpiochip_get_desc(chip, offset));
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}
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EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);
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