mirror of
https://github.com/brain-hackers/u-boot-brain
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![Tom Rini](/assets/img/avatar_default.png)
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
259 lines
6.0 KiB
C
259 lines
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (c) 2014 Google, Inc
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*
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* (C) Copyright 2002
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* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
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*
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* Influenced by code from:
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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*/
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#include <common.h>
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#include <dm.h>
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#include <errno.h>
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#include <fdtdec.h>
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#include <malloc.h>
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#include <spi.h>
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#include <asm/gpio.h>
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DECLARE_GLOBAL_DATA_PTR;
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struct soft_spi_platdata {
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struct gpio_desc cs;
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struct gpio_desc sclk;
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struct gpio_desc mosi;
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struct gpio_desc miso;
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int spi_delay_us;
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int flags;
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};
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#define SPI_MASTER_NO_RX BIT(0)
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#define SPI_MASTER_NO_TX BIT(1)
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struct soft_spi_priv {
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unsigned int mode;
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};
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static int soft_spi_scl(struct udevice *dev, int bit)
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{
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struct udevice *bus = dev_get_parent(dev);
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struct soft_spi_platdata *plat = dev_get_platdata(bus);
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dm_gpio_set_value(&plat->sclk, bit);
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return 0;
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}
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static int soft_spi_sda(struct udevice *dev, int bit)
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{
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struct udevice *bus = dev_get_parent(dev);
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struct soft_spi_platdata *plat = dev_get_platdata(bus);
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dm_gpio_set_value(&plat->mosi, bit);
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return 0;
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}
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static int soft_spi_cs_activate(struct udevice *dev)
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{
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struct udevice *bus = dev_get_parent(dev);
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struct soft_spi_platdata *plat = dev_get_platdata(bus);
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dm_gpio_set_value(&plat->cs, 0);
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dm_gpio_set_value(&plat->sclk, 0);
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dm_gpio_set_value(&plat->cs, 1);
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return 0;
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}
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static int soft_spi_cs_deactivate(struct udevice *dev)
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{
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struct udevice *bus = dev_get_parent(dev);
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struct soft_spi_platdata *plat = dev_get_platdata(bus);
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dm_gpio_set_value(&plat->cs, 0);
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return 0;
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}
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static int soft_spi_claim_bus(struct udevice *dev)
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{
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/*
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* Make sure the SPI clock is in idle state as defined for
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* this slave.
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*/
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return soft_spi_scl(dev, 0);
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}
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static int soft_spi_release_bus(struct udevice *dev)
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{
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/* Nothing to do */
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return 0;
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}
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/*-----------------------------------------------------------------------
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* SPI transfer
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*
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* This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
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* "bitlen" bits in the SPI MISO port. That's just the way SPI works.
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*
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* The source of the outgoing bits is the "dout" parameter and the
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* destination of the input bits is the "din" parameter. Note that "dout"
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* and "din" can point to the same memory location, in which case the
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* input data overwrites the output data (since both are buffered by
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* temporary variables, this is OK).
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*/
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static int soft_spi_xfer(struct udevice *dev, unsigned int bitlen,
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const void *dout, void *din, unsigned long flags)
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{
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struct udevice *bus = dev_get_parent(dev);
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struct soft_spi_priv *priv = dev_get_priv(bus);
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struct soft_spi_platdata *plat = dev_get_platdata(bus);
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uchar tmpdin = 0;
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uchar tmpdout = 0;
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const u8 *txd = dout;
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u8 *rxd = din;
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int cpha = priv->mode & SPI_CPHA;
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unsigned int j;
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debug("spi_xfer: slave %s:%s dout %08X din %08X bitlen %u\n",
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dev->parent->name, dev->name, *(uint *)txd, *(uint *)rxd,
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bitlen);
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if (flags & SPI_XFER_BEGIN)
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soft_spi_cs_activate(dev);
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for (j = 0; j < bitlen; j++) {
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/*
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* Check if it is time to work on a new byte.
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*/
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if ((j % 8) == 0) {
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if (txd)
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tmpdout = *txd++;
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else
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tmpdout = 0;
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if (j != 0) {
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if (rxd)
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*rxd++ = tmpdin;
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}
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tmpdin = 0;
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}
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if (!cpha)
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soft_spi_scl(dev, 0);
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if ((plat->flags & SPI_MASTER_NO_TX) == 0)
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soft_spi_sda(dev, !!(tmpdout & 0x80));
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udelay(plat->spi_delay_us);
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if (cpha)
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soft_spi_scl(dev, 0);
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else
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soft_spi_scl(dev, 1);
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tmpdin <<= 1;
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if ((plat->flags & SPI_MASTER_NO_RX) == 0)
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tmpdin |= dm_gpio_get_value(&plat->miso);
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tmpdout <<= 1;
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udelay(plat->spi_delay_us);
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if (cpha)
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soft_spi_scl(dev, 1);
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}
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/*
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* If the number of bits isn't a multiple of 8, shift the last
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* bits over to left-justify them. Then store the last byte
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* read in.
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*/
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if (rxd) {
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if ((bitlen % 8) != 0)
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tmpdin <<= 8 - (bitlen % 8);
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*rxd++ = tmpdin;
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}
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if (flags & SPI_XFER_END)
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soft_spi_cs_deactivate(dev);
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return 0;
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}
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static int soft_spi_set_speed(struct udevice *dev, unsigned int speed)
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{
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/* Accept any speed */
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return 0;
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}
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static int soft_spi_set_mode(struct udevice *dev, unsigned int mode)
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{
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struct soft_spi_priv *priv = dev_get_priv(dev);
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priv->mode = mode;
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return 0;
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}
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static const struct dm_spi_ops soft_spi_ops = {
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.claim_bus = soft_spi_claim_bus,
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.release_bus = soft_spi_release_bus,
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.xfer = soft_spi_xfer,
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.set_speed = soft_spi_set_speed,
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.set_mode = soft_spi_set_mode,
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};
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static int soft_spi_ofdata_to_platdata(struct udevice *dev)
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{
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struct soft_spi_platdata *plat = dev->platdata;
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const void *blob = gd->fdt_blob;
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int node = dev_of_offset(dev);
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plat->spi_delay_us = fdtdec_get_int(blob, node, "spi-delay-us", 0);
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return 0;
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}
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static int soft_spi_probe(struct udevice *dev)
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{
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struct spi_slave *slave = dev_get_parent_priv(dev);
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struct soft_spi_platdata *plat = dev->platdata;
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int cs_flags, clk_flags;
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int ret;
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cs_flags = (slave->mode & SPI_CS_HIGH) ? 0 : GPIOD_ACTIVE_LOW;
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clk_flags = (slave->mode & SPI_CPOL) ? GPIOD_ACTIVE_LOW : 0;
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if (gpio_request_by_name(dev, "cs-gpios", 0, &plat->cs,
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GPIOD_IS_OUT | cs_flags) ||
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gpio_request_by_name(dev, "gpio-sck", 0, &plat->sclk,
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GPIOD_IS_OUT | clk_flags))
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return -EINVAL;
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ret = gpio_request_by_name(dev, "gpio-mosi", 0, &plat->mosi,
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GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
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if (ret)
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plat->flags |= SPI_MASTER_NO_TX;
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ret = gpio_request_by_name(dev, "gpio-miso", 0, &plat->miso,
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GPIOD_IS_IN);
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if (ret)
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plat->flags |= SPI_MASTER_NO_RX;
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if ((plat->flags & (SPI_MASTER_NO_RX | SPI_MASTER_NO_TX)) ==
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(SPI_MASTER_NO_RX | SPI_MASTER_NO_TX))
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return -EINVAL;
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return 0;
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}
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static const struct udevice_id soft_spi_ids[] = {
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{ .compatible = "spi-gpio" },
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{ }
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};
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U_BOOT_DRIVER(soft_spi) = {
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.name = "soft_spi",
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.id = UCLASS_SPI,
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.of_match = soft_spi_ids,
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.ops = &soft_spi_ops,
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.ofdata_to_platdata = soft_spi_ofdata_to_platdata,
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.platdata_auto_alloc_size = sizeof(struct soft_spi_platdata),
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.priv_auto_alloc_size = sizeof(struct soft_spi_priv),
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.probe = soft_spi_probe,
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};
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