freebsd-skq/sys/dev/sdhci/sdhci_fdt_gpio.h
ian 98ba506e4b Add new helper routines for sdhci bridge drivers that use gpio pins for
card presence and write protect switch detection.

A bridge driver just needs to call the setup routine in its attach(), the
teardown in its detach(), and write a couple tiny glue functions to connect
the sdhci interface functions to the new helper functions.  This is not
extensively documented, but multiple examples will exist real soon.
2017-01-09 01:54:36 +00:00

70 lines
2.9 KiB
C

/*-
* 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