// 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(sizeof(*dev), GFP_KERNEL);
	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");