// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * AD714X CapTouch Programmable Controller driver (SPI bus)
 *
 * Copyright 2009-2011 Analog Devices Inc.
 */

#include <linux/input.h>        /* BUS_SPI */
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/pm.h>
#include <linux/types.h>
#include "ad714x.h"

#define AD714x_SPI_CMD_PREFIX      0xE000   /* bits 15:11 */
#define AD714x_SPI_READ            BIT(10)

static int ad714x_spi_read(struct ad714x_chip *chip,
                           unsigned short reg, unsigned short *data, size_t len)
{
        struct spi_device *spi = to_spi_device(chip->dev);
        struct spi_message message;
        struct spi_transfer xfer[2];
        int i;
        int error;

        spi_message_init(&message);
        memset(xfer, 0, sizeof(xfer));

        chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
                                        AD714x_SPI_READ | reg);
        xfer[0].tx_buf = &chip->xfer_buf[0];
        xfer[0].len = sizeof(chip->xfer_buf[0]);
        spi_message_add_tail(&xfer[0], &message);

        xfer[1].rx_buf = &chip->xfer_buf[1];
        xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
        spi_message_add_tail(&xfer[1], &message);

        error = spi_sync(spi, &message);
        if (unlikely(error)) {
                dev_err(chip->dev, "SPI read error: %d\n", error);
                return error;
        }

        for (i = 0; i < len; i++)
                data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);

        return 0;
}

static int ad714x_spi_write(struct ad714x_chip *chip,
                            unsigned short reg, unsigned short data)
{
        struct spi_device *spi = to_spi_device(chip->dev);
        int error;

        chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
        chip->xfer_buf[1] = cpu_to_be16(data);

        error = spi_write(spi, (u8 *)chip->xfer_buf,
                          2 * sizeof(*chip->xfer_buf));
        if (unlikely(error)) {
                dev_err(chip->dev, "SPI write error: %d\n", error);
                return error;
        }

        return 0;
}

static int ad714x_spi_probe(struct spi_device *spi)
{
        struct ad714x_chip *chip;
        int err;

        spi->bits_per_word = 8;
        err = spi_setup(spi);
        if (err < 0)
                return err;

        chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
                            ad714x_spi_read, ad714x_spi_write);
        if (IS_ERR(chip))
                return PTR_ERR(chip);

        spi_set_drvdata(spi, chip);

        return 0;
}

static struct spi_driver ad714x_spi_driver = {
        .driver = {
                .name   = "ad714x_captouch",
                .pm     = pm_sleep_ptr(&ad714x_pm),
        },
        .probe          = ad714x_spi_probe,
};

module_spi_driver(ad714x_spi_driver);

MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
MODULE_LICENSE("GPL");