linux-imx

/*

 * NBUS driver for TS-4600 based boards

 *

 * Copyright (c) 2016 - Savoir-faire Linux

 * Author: Sebastien Bourdelin <sebastien.bourdelin@savoirfairelinux.com>

 *

 * This file is licensed under the terms of the GNU General Public

 * License version 2. This program is licensed "as is" without any

 * warranty of any kind, whether express or implied.

 *

 * This driver implements a GPIOs bit-banged bus, called the NBUS by Technologic

 * Systems. It is used to communicate with the peripherals in the FPGA on the

 * TS-4600 SoM.

 */

​

#include <linux/bitops.h>

#include <linux/gpio/consumer.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of_platform.h>

#include <linux/platform_device.h>

#include <linux/pwm.h>

#include <linux/ts-nbus.h>

​

#define TS_NBUS_DIRECTION_IN  0

#define TS_NBUS_DIRECTION_OUT 1

#define TS_NBUS_WRITE_ADR 0

#define TS_NBUS_WRITE_VAL 1

​

struct ts_nbus {

    struct pwm_device *pwm;

    struct gpio_descs *data;

    struct gpio_desc *csn;

    struct gpio_desc *txrx;

    struct gpio_desc *strobe;

    struct gpio_desc *ale;

    struct gpio_desc *rdy;

    struct mutex lock;

};

​

/*

 * request all gpios required by the bus.

 */

static int ts_nbus_init_pdata(struct platform_device *pdev, struct ts_nbus

        *ts_nbus)

{

    ts_nbus->data = devm_gpiod_get_array(&pdev->dev, "ts,data",

            GPIOD_OUT_HIGH);

    if (IS_ERR(ts_nbus->data)) {

        dev_err(&pdev->dev, "failed to retrieve ts,data-gpio from dts\n");

        return PTR_ERR(ts_nbus->data);

    }

​

    ts_nbus->csn = devm_gpiod_get(&pdev->dev, "ts,csn", GPIOD_OUT_HIGH);

    if (IS_ERR(ts_nbus->csn)) {

        dev_err(&pdev->dev, "failed to retrieve ts,csn-gpio from dts\n");

        return PTR_ERR(ts_nbus->csn);

    }

​

    ts_nbus->txrx = devm_gpiod_get(&pdev->dev, "ts,txrx", GPIOD_OUT_HIGH);

    if (IS_ERR(ts_nbus->txrx)) {

        dev_err(&pdev->dev, "failed to retrieve ts,txrx-gpio from dts\n");