// SPDX-License-Identifier: GPL-2.0
/* DSA driver for:
 * Vitesse VSC7385 SparX-G5 5+1-port Integrated Gigabit Ethernet Switch
 * Vitesse VSC7388 SparX-G8 8-port Integrated Gigabit Ethernet Switch
 * Vitesse VSC7395 SparX-G5e 5+1-port Integrated Gigabit Ethernet Switch
 * Vitesse VSC7398 SparX-G8e 8-port Integrated Gigabit Ethernet Switch
 *
 * This driver takes control of the switch chip over SPI and
 * configures it to route packages around when connected to a CPU port.
 *
 * Copyright (C) 2018 Linus Wallej <linus.walleij@linaro.org>
 * Includes portions of code from the firmware uploader by:
 * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/spi/spi.h>

#include "vitesse-vsc73xx.h"

#define VSC73XX_CMD_SPI_MODE_READ               0
#define VSC73XX_CMD_SPI_MODE_WRITE              1
#define VSC73XX_CMD_SPI_MODE_SHIFT              4
#define VSC73XX_CMD_SPI_BLOCK_SHIFT             5
#define VSC73XX_CMD_SPI_BLOCK_MASK              0x7
#define VSC73XX_CMD_SPI_SUBBLOCK_MASK           0xf

/*
 * struct vsc73xx_spi - VSC73xx SPI state container
 */
struct vsc73xx_spi {
        struct spi_device       *spi;
        struct mutex            lock; /* Protects SPI traffic */
        struct vsc73xx          vsc;
};

static const struct vsc73xx_ops vsc73xx_spi_ops;

static u8 vsc73xx_make_addr(u8 mode, u8 block, u8 subblock)
{
        u8 ret;

        ret =
            (block & VSC73XX_CMD_SPI_BLOCK_MASK) << VSC73XX_CMD_SPI_BLOCK_SHIFT;
        ret |= (mode & 1) << VSC73XX_CMD_SPI_MODE_SHIFT;
        ret |= subblock & VSC73XX_CMD_SPI_SUBBLOCK_MASK;

        return ret;
}

static int vsc73xx_spi_read(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
                            u32 *val)
{
        struct vsc73xx_spi *vsc_spi = vsc->priv;
        struct spi_transfer t[2];
        struct spi_message m;
        u8 cmd[4];
        u8 buf[4];
        int ret;

        if (!vsc73xx_is_addr_valid(block, subblock))
                return -EINVAL;

        spi_message_init(&m);

        memset(&t, 0, sizeof(t));

        t[0].tx_buf = cmd;
        t[0].len = sizeof(cmd);
        spi_message_add_tail(&t[0], &m);

        t[1].rx_buf = buf;
        t[1].len = sizeof(buf);
        spi_message_add_tail(&t[1], &m);

        cmd[0] = vsc73xx_make_addr(VSC73XX_CMD_SPI_MODE_READ, block, subblock);
        cmd[1] = reg;
        cmd[2] = 0;
        cmd[3] = 0;

        mutex_lock(&vsc_spi->lock);
        ret = spi_sync(vsc_spi->spi, &m);
        mutex_unlock(&vsc_spi->lock);

        if (ret)
                return ret;

        *val = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];

        return 0;
}

static int vsc73xx_spi_write(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
                             u32 val)
{
        struct vsc73xx_spi *vsc_spi = vsc->priv;
        struct spi_transfer t[2];
        struct spi_message m;
        u8 cmd[2];
        u8 buf[4];
        int ret;

        if (!vsc73xx_is_addr_valid(block, subblock))
                return -EINVAL;

        spi_message_init(&m);

        memset(&t, 0, sizeof(t));

        t[0].tx_buf = cmd;
        t[0].len = sizeof(cmd);
        spi_message_add_tail(&t[0], &m);

        t[1].tx_buf = buf;
        t[1].len = sizeof(buf);
        spi_message_add_tail(&t[1], &m);

        cmd[0] = vsc73xx_make_addr(VSC73XX_CMD_SPI_MODE_WRITE, block, subblock);
        cmd[1] = reg;

        buf[0] = (val >> 24) & 0xff;
        buf[1] = (val >> 16) & 0xff;
        buf[2] = (val >> 8) & 0xff;
        buf[3] = val & 0xff;

        mutex_lock(&vsc_spi->lock);
        ret = spi_sync(vsc_spi->spi, &m);
        mutex_unlock(&vsc_spi->lock);

        return ret;
}

static int vsc73xx_spi_probe(struct spi_device *spi)
{
        struct device *dev = &spi->dev;
        struct vsc73xx_spi *vsc_spi;
        int ret;

        vsc_spi = devm_kzalloc(dev, sizeof(*vsc_spi), GFP_KERNEL);
        if (!vsc_spi)
                return -ENOMEM;

        spi_set_drvdata(spi, vsc_spi);
        vsc_spi->spi = spi_dev_get(spi);
        vsc_spi->vsc.dev = dev;
        vsc_spi->vsc.priv = vsc_spi;
        vsc_spi->vsc.ops = &vsc73xx_spi_ops;
        mutex_init(&vsc_spi->lock);

        spi->mode = SPI_MODE_0;
        spi->bits_per_word = 8;
        ret = spi_setup(spi);
        if (ret < 0) {
                dev_err(dev, "spi setup failed.\n");
                return ret;
        }

        return vsc73xx_probe(&vsc_spi->vsc);
}

static void vsc73xx_spi_remove(struct spi_device *spi)
{
        struct vsc73xx_spi *vsc_spi = spi_get_drvdata(spi);

        if (!vsc_spi)
                return;

        vsc73xx_remove(&vsc_spi->vsc);
}

static void vsc73xx_spi_shutdown(struct spi_device *spi)
{
        struct vsc73xx_spi *vsc_spi = spi_get_drvdata(spi);

        if (!vsc_spi)
                return;

        vsc73xx_shutdown(&vsc_spi->vsc);

        spi_set_drvdata(spi, NULL);
}

static const struct vsc73xx_ops vsc73xx_spi_ops = {
        .read = vsc73xx_spi_read,
        .write = vsc73xx_spi_write,
};

static const struct of_device_id vsc73xx_of_match[] = {
        {
                .compatible = "vitesse,vsc7385",
        },
        {
                .compatible = "vitesse,vsc7388",
        },
        {
                .compatible = "vitesse,vsc7395",
        },
        {
                .compatible = "vitesse,vsc7398",
        },
        { },
};
MODULE_DEVICE_TABLE(of, vsc73xx_of_match);

static const struct spi_device_id vsc73xx_spi_ids[] = {
        { "vsc7385" },
        { "vsc7388" },
        { "vsc7395" },
        { "vsc7398" },
        { },
};
MODULE_DEVICE_TABLE(spi, vsc73xx_spi_ids);

static struct spi_driver vsc73xx_spi_driver = {
        .probe = vsc73xx_spi_probe,
        .remove = vsc73xx_spi_remove,
        .shutdown = vsc73xx_spi_shutdown,
        .id_table = vsc73xx_spi_ids,
        .driver = {
                .name = "vsc73xx-spi",
                .of_match_table = vsc73xx_of_match,
        },
};
module_spi_driver(vsc73xx_spi_driver);

MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_DESCRIPTION("Vitesse VSC7385/7388/7395/7398 SPI driver");
MODULE_LICENSE("GPL v2");