linux-imx

// SPDX-License-Identifier: GPL-2.0+

/*

 * Generic driver for memory-mapped GPIO controllers.

 *

 * Copyright 2008 MontaVista Software, Inc.

 * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>

 *

 * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......

 * ...``                                                         ```````..

 * ..The simplest form of a GPIO controller that the driver supports is``

 *  `.just a single "data" register, where GPIO state can be read and/or `

 *    `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````

 *        `````````

                                    ___

_/~~|___/~|   . ```~~~~~~       ___/___\___     ,~.`.`.`.`````.~~...,,,,...

__________|~$@~~~        %~    /o*o*o*o*o*o\   .. Implementing such a GPIO .

o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`

                                                 `....trivial..'~`.```.```

 *                                                    ```````

 *  .```````~~~~`..`.``.``.

 * .  The driver supports  `...       ,..```.`~~~```````````````....````.``,,

 * .   big-endian notation, just`.  .. A bit more sophisticated controllers ,

 *  . register the device with -be`. .with a pair of set/clear-bit registers ,

 *   `.. suffix.  ```~~`````....`.`   . affecting the data register and the .`

 *     ``.`.``...```                  ```.. output pins are also supported.`

 *                        ^^             `````.`````````.,``~``~``~~``````

 *                                                   .                  ^^

 *   ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..

 * .. The expectation is that in at least some cases .    ,-~~~-,

 *  .this will be used with roll-your-own ASIC/FPGA .`     \   /

 *  .logic in Verilog or VHDL. ~~~`````````..`````~~`       \ /

 *  ..````````......```````````                             \o_

 *                                                           |

 *                              ^^                          / \

 *

 *           ...`````~~`.....``.`..........``````.`.``.```........``.

 *            `  8, 16, 32 and 64 bits registers are supported, and``.

 *            . the number of GPIOs is determined by the width of   ~

 *             .. the registers. ,............```.`.`..`.`.~~~.`.`.`~

 *               `.......````.```

 */

​

#include <linux/init.h>

#include <linux/err.h>

#include <linux/bug.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/spinlock.h>

#include <linux/compiler.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/log2.h>

#include <linux/ioport.h>

#include <linux/io.h>

#include <linux/gpio/driver.h>

#include <linux/slab.h>

#include <linux/bitops.h>

#include <linux/platform_device.h>

#include <linux/mod_devicetable.h>

#include <linux/of.h>

#include <linux/of_device.h>

​

static void bgpio_write8(void __iomem *reg, unsigned long data)