// SPDX-License-Identifier: GPL-2.0
/*
* cypress_cy7c63.c
*
* Copyright (c) 2006-2007 Oliver Bock (bock@tfh-berlin.de)
*
*       This driver is based on the Cypress USB Driver by Marcus Maul
*       (cyport) and the 2.0 version of Greg Kroah-Hartman's
*       USB Skeleton driver.
*
*       This is a generic driver for the Cypress CY7C63xxx family.
*       For the time being it enables you to read from and write to
*       the single I/O ports of the device.
*
*       Supported vendors:      AK Modul-Bus Computer GmbH
*                               (Firmware "Port-Chip")
*
*       Supported devices:      CY7C63001A-PC
*                               CY7C63001C-PXC
*                               CY7C63001C-SXC
*
*       Supported functions:    Read/Write Ports
*
*
*       For up-to-date information please visit:
*       http://www.obock.de/kernel/cypress
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/usb.h>

#define DRIVER_AUTHOR           "Oliver Bock (bock@tfh-berlin.de)"
#define DRIVER_DESC             "Cypress CY7C63xxx USB driver"

#define CYPRESS_VENDOR_ID       0xa2c
#define CYPRESS_PRODUCT_ID      0x8

#define CYPRESS_READ_PORT       0x4
#define CYPRESS_WRITE_PORT      0x5

#define CYPRESS_READ_RAM        0x2
#define CYPRESS_WRITE_RAM       0x3
#define CYPRESS_READ_ROM        0x1

#define CYPRESS_READ_PORT_ID0   0
#define CYPRESS_WRITE_PORT_ID0  0
#define CYPRESS_READ_PORT_ID1   0x2
#define CYPRESS_WRITE_PORT_ID1  1

#define CYPRESS_MAX_REQSIZE     8


/* table of devices that work with this driver */
static const struct usb_device_id cypress_table[] = {
        { USB_DEVICE(CYPRESS_VENDOR_ID, CYPRESS_PRODUCT_ID) },
        { }
};
MODULE_DEVICE_TABLE(usb, cypress_table);

/* structure to hold all of our device specific stuff */
struct cypress {
        struct usb_device *     udev;
        unsigned char           port[2];
};

/* used to send usb control messages to device */
static int vendor_command(struct cypress *dev, unsigned char request,
                          unsigned char address, unsigned char data)
{
        int retval = 0;
        unsigned int pipe;
        unsigned char *iobuf;

        /* allocate some memory for the i/o buffer*/
        iobuf = kzalloc(CYPRESS_MAX_REQSIZE, GFP_KERNEL);
        if (!iobuf) {
                retval = -ENOMEM;
                goto error;
        }

        dev_dbg(&dev->udev->dev, "Sending usb_control_msg (data: %d)\n", data);

        /* prepare usb control message and send it upstream */
        pipe = usb_rcvctrlpipe(dev->udev, 0);
        retval = usb_control_msg(dev->udev, pipe, request,
                                 USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
                                 address, data, iobuf, CYPRESS_MAX_REQSIZE,
                                 USB_CTRL_GET_TIMEOUT);
        /* we must not process garbage */
        if (retval < 2)
                goto err_buf;

        /* store returned data (more READs to be added) */
        switch (request) {
                case CYPRESS_READ_PORT:
                        if (address == CYPRESS_READ_PORT_ID0) {
                                dev->port[0] = iobuf[1];
                                dev_dbg(&dev->udev->dev,
                                        "READ_PORT0 returned: %d\n",
                                        dev->port[0]);
                        }
                        else if (address == CYPRESS_READ_PORT_ID1) {
                                dev->port[1] = iobuf[1];
                                dev_dbg(&dev->udev->dev,
                                        "READ_PORT1 returned: %d\n",
                                        dev->port[1]);
                        }
                        break;
        }

err_buf:
        kfree(iobuf);
error:
        return retval;
}

/* write port value */
static ssize_t write_port(struct device *dev, struct device_attribute *attr,
                          const char *buf, size_t count,
                          int port_num, int write_id)
{
        int value = -1;
        int result = 0;

        struct usb_interface *intf = to_usb_interface(dev);
        struct cypress *cyp = usb_get_intfdata(intf);

        dev_dbg(&cyp->udev->dev, "WRITE_PORT%d called\n", port_num);

        /* validate input data */
        if (sscanf(buf, "%d", &value) < 1) {
                result = -EINVAL;
                goto error;
        }
        if (value < 0 || value > 255) {
                result = -EINVAL;
                goto error;
        }

        result = vendor_command(cyp, CYPRESS_WRITE_PORT, write_id,
                                (unsigned char)value);

        dev_dbg(&cyp->udev->dev, "Result of vendor_command: %d\n\n", result);
error:
        return result < 0 ? result : count;
}

/* attribute callback handler (write) */
static ssize_t port0_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        return write_port(dev, attr, buf, count, 0, CYPRESS_WRITE_PORT_ID0);
}

/* attribute callback handler (write) */
static ssize_t port1_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        return write_port(dev, attr, buf, count, 1, CYPRESS_WRITE_PORT_ID1);
}

/* read port value */
static ssize_t read_port(struct device *dev, struct device_attribute *attr,
                         char *buf, int port_num, int read_id)
{
        int result = 0;

        struct usb_interface *intf = to_usb_interface(dev);
        struct cypress *cyp = usb_get_intfdata(intf);

        dev_dbg(&cyp->udev->dev, "READ_PORT%d called\n", port_num);

        result = vendor_command(cyp, CYPRESS_READ_PORT, read_id, 0);

        dev_dbg(&cyp->udev->dev, "Result of vendor_command: %d\n\n", result);

        return sprintf(buf, "%d", cyp->port[port_num]);
}

/* attribute callback handler (read) */
static ssize_t port0_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        return read_port(dev, attr, buf, 0, CYPRESS_READ_PORT_ID0);
}
static DEVICE_ATTR_RW(port0);

/* attribute callback handler (read) */
static ssize_t port1_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        return read_port(dev, attr, buf, 1, CYPRESS_READ_PORT_ID1);
}
static DEVICE_ATTR_RW(port1);

static struct attribute *cypress_attrs[] = {
        &dev_attr_port0.attr,
        &dev_attr_port1.attr,
        NULL,
};
ATTRIBUTE_GROUPS(cypress);

static int cypress_probe(struct usb_interface *interface,
                         const struct usb_device_id *id)
{
        struct cypress *dev;
        int retval = -ENOMEM;

        /* allocate memory for our device state and initialize it */
        dev = kzalloc_obj(*dev);
        if (!dev)
                goto error_mem;

        dev->udev = usb_get_dev(interface_to_usbdev(interface));

        /* save our data pointer in this interface device */
        usb_set_intfdata(interface, dev);

        /* let the user know that the device is now attached */
        dev_info(&interface->dev,
                 "Cypress CY7C63xxx device now attached\n");
        return 0;

error_mem:
        return retval;
}

static void cypress_disconnect(struct usb_interface *interface)
{
        struct cypress *dev;

        dev = usb_get_intfdata(interface);

        /* the intfdata can be set to NULL only after the
         * device files have been removed */
        usb_set_intfdata(interface, NULL);

        usb_put_dev(dev->udev);

        dev_info(&interface->dev,
                 "Cypress CY7C63xxx device now disconnected\n");

        kfree(dev);
}

static struct usb_driver cypress_driver = {
        .name = "cypress_cy7c63",
        .probe = cypress_probe,
        .disconnect = cypress_disconnect,
        .id_table = cypress_table,
        .dev_groups = cypress_groups,
};

module_usb_driver(cypress_driver);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);

MODULE_LICENSE("GPL");