linux-imx

// SPDX-License-Identifier: GPL-2.0-only

/*

 * Driver for the Diolan DLN-2 USB adapter

 *

 * Copyright (c) 2014 Intel Corporation

 *

 * Derived from:

 *  i2c-diolan-u2c.c

 *  Copyright (c) 2010-2011 Ericsson AB

 */

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/types.h>

#include <linux/slab.h>

#include <linux/usb.h>

#include <linux/i2c.h>

#include <linux/mutex.h>

#include <linux/platform_device.h>

#include <linux/mfd/core.h>

#include <linux/mfd/dln2.h>

#include <linux/rculist.h>

​

struct dln2_header {

    __le16 size;

    __le16 id;

    __le16 echo;

    __le16 handle;

};

​

struct dln2_response {

    struct dln2_header hdr;

    __le16 result;

};

​

#define DLN2_GENERIC_MODULE_ID      0x00

#define DLN2_GENERIC_CMD(cmd)       DLN2_CMD(cmd, DLN2_GENERIC_MODULE_ID)

#define CMD_GET_DEVICE_VER      DLN2_GENERIC_CMD(0x30)

#define CMD_GET_DEVICE_SN       DLN2_GENERIC_CMD(0x31)

​

#define DLN2_HW_ID          0x200

#define DLN2_USB_TIMEOUT        200 /* in ms */

#define DLN2_MAX_RX_SLOTS       16

#define DLN2_MAX_URBS           16

#define DLN2_RX_BUF_SIZE        512

​

enum dln2_handle {

    DLN2_HANDLE_EVENT = 0,      /* don't change, hardware defined */

    DLN2_HANDLE_CTRL,

    DLN2_HANDLE_GPIO,

    DLN2_HANDLE_I2C,

    DLN2_HANDLE_SPI,

    DLN2_HANDLES

};

​

/*

 * Receive context used between the receive demultiplexer and the transfer

 * routine. While sending a request the transfer routine will look for a free

 * receive context and use it to wait for a response and to receive the URB and

 * thus the response data.

 */

struct dln2_rx_context {

    /* completion used to wait for a response */

    struct completion done;

​

    /* if non-NULL the URB contains the response */

    struct urb *urb;

​

    /* if true then this context is used to wait for a response */

    bool in_use;

};

​

/*

 * Receive contexts for a particular DLN2 module (i2c, gpio, etc.). We use the

 * handle header field to identify the module in dln2_dev.mod_rx_slots and then

 * the echo header field to index the slots field and find the receive context

 * for a particular request.

 */

struct dln2_mod_rx_slots {

    /* RX slots bitmap */

    DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS);

​

    /* used to wait for a free RX slot */

    wait_queue_head_t wq;

​

    /* used to wait for an RX operation to complete */

    struct dln2_rx_context slots[DLN2_MAX_RX_SLOTS];

​

    /* avoid races between alloc/free_rx_slot and dln2_rx_transfer */

    spinlock_t lock;

};

​