FreeBSD/Linux Kernel Cross Reference
sys/dev/sdhci/sdhci_fdt_gpio.h

     /*-
      * Copyright (c) 2017 Ian Lepore <ian@freebsd.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    /*
     * Support routines usable by any SoC sdhci bridge driver that uses gpio pins
     * for card detect and/or write protect, and uses FDT data to describe those
     * pins.  A bridge driver need only supply a couple 2-line forwarding functions
     * to connect the get_present and get_readonly accessors to the corresponding
     * driver interface functions, and add setup/teardown calls to its attach and
     * detach functions.
     */
    
    #ifndef _SDHCI_FDT_GPIO_H_
    #define _SDHCI_FDT_GPIO_H_
    
    struct sdhci_slot;
    struct sdhci_fdt_gpio;
    
    /*
     * sdhci_fdt_gpio_setup()
     * sdhci_fdt_gpio_teardown()
     *
     * Process FDT properties that use gpio pins and set up interrupt handling (if
     * supported by hardware) and accessor functions to read the pins.
     *
     * Setup cannot fail.  If the properties are not present, the accessors will
     * return the values from standard sdhci registers.  If the gpio controller
     * can't trigger interrupts on both edges, it configures the slot to use polling
     * for card presence detection.  If it can't access the gpio pin at all it sets
     * up the get_present() accessor to always return true.  Likewise the
     * get_readonly() accessor always returns false if its pin can't be accessed.
     */
    struct sdhci_fdt_gpio *sdhci_fdt_gpio_setup(device_t dev, struct sdhci_slot *slot);
    void sdhci_fdt_gpio_teardown(struct sdhci_fdt_gpio *gpio);
    
    /*
     * sdhci_fdt_gpio_get_present()
     * sdhci_fdt_gpio_get_readonly()
     *
     * Gpio pin state accessor functions.
     */
    bool sdhci_fdt_gpio_get_present(struct sdhci_fdt_gpio *gpio);
    int  sdhci_fdt_gpio_get_readonly(struct sdhci_fdt_gpio *gpio);
    
    #endif

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