linux-imx

/*

 * Xilinx Spartan6 Slave Serial SPI Driver

 *

 * Copyright (C) 2017 DENX Software Engineering

 *

 * Anatolij Gustschin <agust@denx.de>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * Manage Xilinx FPGA firmware that is loaded over SPI using

 * the slave serial configuration interface.

 */

​

#include <linux/delay.h>

#include <linux/device.h>

#include <linux/fpga/fpga-mgr.h>

#include <linux/gpio/consumer.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>

#include <linux/of.h>

#include <linux/spi/spi.h>

#include <linux/sizes.h>

​

struct xilinx_spi_conf {

    struct spi_device *spi;

    struct gpio_desc *prog_b;

    struct gpio_desc *done;

};

​

static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)

{

    struct xilinx_spi_conf *conf = mgr->priv;

​

    if (!gpiod_get_value(conf->done))

        return FPGA_MGR_STATE_RESET;

​

    return FPGA_MGR_STATE_UNKNOWN;

}

​

static int xilinx_spi_write_init(struct fpga_manager *mgr,

                 struct fpga_image_info *info,

                 const char *buf, size_t count)

{

    struct xilinx_spi_conf *conf = mgr->priv;

    const size_t prog_latency_7500us = 7500;

    const size_t prog_pulse_1us = 1;

​

    if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {

        dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");

        return -EINVAL;

    }

​

    gpiod_set_value(conf->prog_b, 1);

​

    udelay(prog_pulse_1us); /* min is 500 ns */

​

    gpiod_set_value(conf->prog_b, 0);

​

    if (gpiod_get_value(conf->done)) {

        dev_err(&mgr->dev, "Unexpected DONE pin state...\n");

        return -EIO;