// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ADLX345/346 Three-Axis Digital Accelerometers (SPI Interface)
 *
 * Enter bugs at http://blackfin.uclinux.org/
 *
 * Copyright (C) 2009 Michael Hennerich, 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 "adxl34x.h"

#define MAX_SPI_FREQ_HZ         5000000
#define MAX_FREQ_NO_FIFODELAY   1500000
#define ADXL34X_CMD_MULTB       (1 << 6)
#define ADXL34X_CMD_READ        (1 << 7)
#define ADXL34X_WRITECMD(reg)   (reg & 0x3F)
#define ADXL34X_READCMD(reg)    (ADXL34X_CMD_READ | (reg & 0x3F))
#define ADXL34X_READMB_CMD(reg) (ADXL34X_CMD_READ | ADXL34X_CMD_MULTB \
                                        | (reg & 0x3F))

static int adxl34x_spi_read(struct device *dev, unsigned char reg)
{
        struct spi_device *spi = to_spi_device(dev);
        unsigned char cmd;

        cmd = ADXL34X_READCMD(reg);

        return spi_w8r8(spi, cmd);
}

static int adxl34x_spi_write(struct device *dev,
                             unsigned char reg, unsigned char val)
{
        struct spi_device *spi = to_spi_device(dev);
        unsigned char buf[2];

        buf[0] = ADXL34X_WRITECMD(reg);
        buf[1] = val;

        return spi_write(spi, buf, sizeof(buf));
}

static int adxl34x_spi_read_block(struct device *dev,
                                  unsigned char reg, int count,
                                  void *buf)
{
        struct spi_device *spi = to_spi_device(dev);
        ssize_t status;

        reg = ADXL34X_READMB_CMD(reg);
        status = spi_write_then_read(spi, &reg, 1, buf, count);

        return (status < 0) ? status : 0;
}

static const struct adxl34x_bus_ops adxl34x_spi_bops = {
        .bustype        = BUS_SPI,
        .write          = adxl34x_spi_write,
        .read           = adxl34x_spi_read,
        .read_block     = adxl34x_spi_read_block,
};

static int adxl34x_spi_probe(struct spi_device *spi)
{
        struct adxl34x *ac;

        /* don't exceed max specified SPI CLK frequency */
        if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
                dev_err(&spi->dev, "SPI CLK %d Hz too fast\n", spi->max_speed_hz);
                return -EINVAL;
        }

        ac = adxl34x_probe(&spi->dev, spi->irq,
                           spi->max_speed_hz > MAX_FREQ_NO_FIFODELAY,
                           &adxl34x_spi_bops);

        if (IS_ERR(ac))
                return PTR_ERR(ac);

        spi_set_drvdata(spi, ac);

        return 0;
}

static struct spi_driver adxl34x_driver = {
        .driver = {
                .name = "adxl34x",
                .dev_groups = adxl34x_groups,
                .pm = pm_sleep_ptr(&adxl34x_pm),
        },
        .probe   = adxl34x_spi_probe,
};

module_spi_driver(adxl34x_driver);

MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("ADXL345/346 Three-Axis Digital Accelerometer SPI Bus Driver");
MODULE_LICENSE("GPL");