linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (C) 2015-2017 Pengutronix, Uwe Kleine-König <kernel@pengutronix.de>

 */

​

#include <linux/gpio/consumer.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>

#include <linux/platform_device.h>

​

#include <linux/delay.h>

​

#include "siox.h"

​

#define DRIVER_NAME "siox-gpio"

​

struct siox_gpio_ddata {

    struct gpio_desc *din;

    struct gpio_desc *dout;

    struct gpio_desc *dclk;

    struct gpio_desc *dld;

};

​

static unsigned int siox_clkhigh_ns = 1000;

static unsigned int siox_loadhigh_ns;

static unsigned int siox_bytegap_ns;

​

static int siox_gpio_pushpull(struct siox_master *smaster,

                  size_t setbuf_len, const u8 setbuf[],

                  size_t getbuf_len, u8 getbuf[])

{

    struct siox_gpio_ddata *ddata = siox_master_get_devdata(smaster);

    size_t i;

    size_t cycles = max(setbuf_len, getbuf_len);

​

    /* reset data and clock */

    gpiod_set_value_cansleep(ddata->dout, 0);

    gpiod_set_value_cansleep(ddata->dclk, 0);

​

    gpiod_set_value_cansleep(ddata->dld, 1);

    ndelay(siox_loadhigh_ns);

    gpiod_set_value_cansleep(ddata->dld, 0);

​

    for (i = 0; i < cycles; ++i) {

        u8 set = 0, get = 0;

        size_t j;

​

        if (i >= cycles - setbuf_len)

            set = setbuf[i - (cycles - setbuf_len)];

​

        for (j = 0; j < 8; ++j) {

            get <<= 1;

            if (gpiod_get_value_cansleep(ddata->din))

                get |= 1;

​

            /* DOUT is logically inverted */

            gpiod_set_value_cansleep(ddata->dout, !(set & 0x80));

            set <<= 1;

​

            gpiod_set_value_cansleep(ddata->dclk, 1);

            ndelay(siox_clkhigh_ns);

            gpiod_set_value_cansleep(ddata->dclk, 0);

        }

​

        if (i < getbuf_len)

            getbuf[i] = get;

​

        ndelay(siox_bytegap_ns);

    }

​

    gpiod_set_value_cansleep(ddata->dld, 1);

    ndelay(siox_loadhigh_ns);

    gpiod_set_value_cansleep(ddata->dld, 0);

​

    /*

     * Resetting dout isn't necessary protocol wise, but it makes the

     * signals more pretty because the dout level is deterministic between

     * cycles. Note that this only affects dout between the master and the

     * first siox device. dout for the later devices depend on the output of

     * the previous siox device.

     */

    gpiod_set_value_cansleep(ddata->dout, 0);

​

    return 0;

}

​

static int siox_gpio_probe(struct platform_device *pdev)

{

    struct device *dev = &pdev->dev;

    struct siox_gpio_ddata *ddata;

    int ret;

    struct siox_master *smaster;