uboot-phytec

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

/*

 * Take drivers/gpio/gpio-74x164.c as reference.

 *

 * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver

 *

 * Copyright (C) 2016 Peng Fan <van.freenix@gmail.com>

 *

 */

​

#include <common.h>

#include <errno.h>

#include <dm.h>

#include <fdtdec.h>

#include <malloc.h>

#include <asm/gpio.h>

#include <asm/io.h>

#include <dt-bindings/gpio/gpio.h>

#include <spi.h>

​

DECLARE_GLOBAL_DATA_PTR;

​

/*

 * struct gen_74x164_chip - Data for 74Hx164

 *

 * @oe: OE pin

 * @nregs: number of registers

 * @buffer: buffer for chained chips

 */

#define GEN_74X164_NUMBER_GPIOS 8

​

struct gen_74x164_priv {

    struct gpio_desc oe;

    u32 nregs;

    /*

     * Since the nregs are chained, every byte sent will make

     * the previous byte shift to the next register in the

     * chain. Thus, the first byte sent will end up in the last

     * register at the end of the transfer. So, to have a logical

     * numbering, store the bytes in reverse order.

     */

    u8 *buffer;

};

​

static int gen_74x164_write_conf(struct udevice *dev)

{

    struct gen_74x164_priv *priv = dev_get_priv(dev);

    int ret;

​

    ret = dm_spi_claim_bus(dev);

    if (ret)

        return ret;

​

    ret = dm_spi_xfer(dev, priv->nregs * 8, priv->buffer, NULL,

              SPI_XFER_BEGIN | SPI_XFER_END);

​

    dm_spi_release_bus(dev);

​

    return ret;

}

​

static int gen_74x164_get_value(struct udevice *dev, unsigned offset)

{