text: // SPDX-License-Identifier: GPL-2.0
  /* -*- linux-c -*-
   * Cypress USB Thermometer driver 
   * 
   * Copyright (c) 2004 Erik Rigtorp <erkki@linux.nu> <erik@rigtorp.com>
   * 
   * This driver works with Elektor magazine USB Interface as published in 
   * issue #291. It should also work with the original starter kit/demo board
   * from Cypress.
   */
  
  
  #include <linux/kernel.h>
  #include <linux/errno.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  #include <linux/usb.h>
  
  #define DRIVER_AUTHOR "Erik Rigtorp"
  #define DRIVER_DESC "Cypress USB Thermometer driver"
  
  #define USB_SKEL_VENDOR_ID	0x04b4
  #define USB_SKEL_PRODUCT_ID	0x0002
  
  static const struct usb_device_id id_table[] = {
  	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
  	{ }
  };
  MODULE_DEVICE_TABLE (usb, id_table);
  
  /* Structure to hold all of our device specific stuff */
  struct usb_cytherm {
  	struct usb_device    *udev;	 /* save off the usb device pointer */
  	struct usb_interface *interface; /* the interface for this device */
  	int brightness;
  };
  
  
  /* local function prototypes */
  static int cytherm_probe(struct usb_interface *interface, 
  			 const struct usb_device_id *id);
  static void cytherm_disconnect(struct usb_interface *interface);
  
  
  /* usb specific object needed to register this driver with the usb subsystem */
  static struct usb_driver cytherm_driver = {
  	.name =		"cytherm",
  	.probe =	cytherm_probe,
  	.disconnect =	cytherm_disconnect,
  	.id_table =	id_table,
  };
  
  /* Vendor requests */
  /* They all operate on one byte at a time */
  #define PING       0x00
  #define READ_ROM   0x01 /* Reads form ROM, value = address */
  #define READ_RAM   0x02 /* Reads form RAM, value = address */
  #define WRITE_RAM  0x03 /* Write to RAM, value = address, index = data */
  #define READ_PORT  0x04 /* Reads from port, value = address */
  #define WRITE_PORT 0x05 /* Write to port, value = address, index = data */ 
  
  
  /* Send a vendor command to device */
  static int vendor_command(struct usb_device *dev, unsigned char request, 
  			  unsigned char value, unsigned char index,
  			  void *buf, int size)
  {
  	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
  			       request, 
  			       USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
  			       value, 
  			       index, buf, size,
  			       USB_CTRL_GET_TIMEOUT);
  }
  
  
  
  #define BRIGHTNESS 0x2c     /* RAM location for brightness value */
  #define BRIGHTNESS_SEM 0x2b /* RAM location for brightness semaphore */
  
  static ssize_t show_brightness(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct usb_interface *intf = to_usb_interface(dev);    
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);     
  
  	return sprintf(buf, "%i", cytherm->brightness);
  }
  
  static ssize_t set_brightness(struct device *dev, struct device_attribute *attr, const char *buf,
  			      size_t count)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
  
  	unsigned char *buffer;
  	int retval;
     
  	buffer = kmalloc(8, GFP_KERNEL);
  	if (!buffer)
  		return 0;
  
  	cytherm->brightness = simple_strtoul(buf, NULL, 10);
     
  	if (cytherm->brightness > 0xFF)
  		cytherm->brightness = 0xFF;
  	else if (cytherm->brightness < 0)
  		cytherm->brightness = 0;
     
  	/* Set brightness */
  	retval = vendor_command(cytherm->udev, WRITE_RAM, BRIGHTNESS, 
  				cytherm->brightness, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
  	/* Inform µC that we have changed the brightness setting */
  	retval = vendor_command(cytherm->udev, WRITE_RAM, BRIGHTNESS_SEM,
  				0x01, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
     
  	kfree(buffer);
     
  	return count;
  }
  
  static DEVICE_ATTR(brightness, S_IRUGO | S_IWUSR | S_IWGRP, 
  		   show_brightness, set_brightness);
  
  
  #define TEMP 0x33 /* RAM location for temperature */
  #define SIGN 0x34 /* RAM location for temperature sign */
  
  static ssize_t show_temp(struct device *dev, struct device_attribute *attr, char *buf)
  {
  
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
  
  	int retval;
  	unsigned char *buffer;
  
  	int temp, sign;
     
  	buffer = kmalloc(8, GFP_KERNEL);
  	if (!buffer)
  		return 0;
  
  	/* read temperature */
  	retval = vendor_command(cytherm->udev, READ_RAM, TEMP, 0, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
  	temp = buffer[1];
     
  	/* read sign */
  	retval = vendor_command(cytherm->udev, READ_RAM, SIGN, 0, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
  	sign = buffer[1];
  
  	kfree(buffer);
     
  	return sprintf(buf, "%c%i.%i", sign ? '-' : '+', temp >> 1,
  		       5*(temp - ((temp >> 1) << 1)));
  }
  
  
  static ssize_t set_temp(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  {
  	return count;
  }
  
  static DEVICE_ATTR(temp, S_IRUGO, show_temp, set_temp);
  
  
  #define BUTTON 0x7a
  
  static ssize_t show_button(struct device *dev, struct device_attribute *attr, char *buf)
  {
  
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
  
  	int retval;
  	unsigned char *buffer;
  
  	buffer = kmalloc(8, GFP_KERNEL);
  	if (!buffer)
  		return 0;
  
  	/* check button */
  	retval = vendor_command(cytherm->udev, READ_RAM, BUTTON, 0, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
     
  	retval = buffer[1];
  
  	kfree(buffer);
  
  	if (retval)
  		return sprintf(buf, "1");
  	else
  		return sprintf(buf, "0");
  }
  
  
  static ssize_t set_button(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  {
  	return count;
  }
  
  static DEVICE_ATTR(button, S_IRUGO, show_button, set_button);
  
  
  static ssize_t show_port0(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
  
  	int retval;
  	unsigned char *buffer;
  
  	buffer = kmalloc(8, GFP_KERNEL);
  	if (!buffer)
  		return 0;
  
  	retval = vendor_command(cytherm->udev, READ_PORT, 0, 0, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
  
  	retval = buffer[1];
  
  	kfree(buffer);
  
  	return sprintf(buf, "%d", retval);
  }
  
  
  static ssize_t set_port0(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
  
  	unsigned char *buffer;
  	int retval;
  	int tmp;
     
  	buffer = kmalloc(8, GFP_KERNEL);
  	if (!buffer)
  		return 0;
  
  	tmp = simple_strtoul(buf, NULL, 10);
     
  	if (tmp > 0xFF)
  		tmp = 0xFF;
  	else if (tmp < 0)
  		tmp = 0;
     
  	retval = vendor_command(cytherm->udev, WRITE_PORT, 0,
  				tmp, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
  
  	kfree(buffer);
  
  	return count;
  }
  
  static DEVICE_ATTR(port0, S_IRUGO | S_IWUSR | S_IWGRP, show_port0, set_port0);
  
  static ssize_t show_port1(struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
  
  	int retval;
  	unsigned char *buffer;
  
  	buffer = kmalloc(8, GFP_KERNEL);
  	if (!buffer)
  		return 0;
  
  	retval = vendor_command(cytherm->udev, READ_PORT, 1, 0, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
     
  	retval = buffer[1];
  
  	kfree(buffer);
  
  	return sprintf(buf, "%d", retval);
  }
  
  
  static ssize_t set_port1(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
  
  	unsigned char *buffer;
  	int retval;
  	int tmp;
     
  	buffer = kmalloc(8, GFP_KERNEL);
  	if (!buffer)
  		return 0;
  
  	tmp = simple_strtoul(buf, NULL, 10);
     
  	if (tmp > 0xFF)
  		tmp = 0xFF;
  	else if (tmp < 0)
  		tmp = 0;
     
  	retval = vendor_command(cytherm->udev, WRITE_PORT, 1,
  				tmp, buffer, 8);
  	if (retval)
  		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
  
  	kfree(buffer);
  
  	return count;
  }
  
  static DEVICE_ATTR(port1, S_IRUGO | S_IWUSR | S_IWGRP, show_port1, set_port1);
  
  
  
  static int cytherm_probe(struct usb_interface *interface, 
  			 const struct usb_device_id *id)
  {
  	struct usb_device *udev = interface_to_usbdev(interface);
  	struct usb_cytherm *dev = NULL;
  	int retval = -ENOMEM;
  
  	dev = kzalloc (sizeof(struct usb_cytherm), GFP_KERNEL);
  	if (!dev)
  		goto error_mem;
  
  	dev->udev = usb_get_dev(udev);
  
  	usb_set_intfdata (interface, dev);
  
  	dev->brightness = 0xFF;
  
  	retval = device_create_file(&interface->dev, &dev_attr_brightness);
  	if (retval)
  		goto error;
  	retval = device_create_file(&interface->dev, &dev_attr_temp);
  	if (retval)
  		goto error;
  	retval = device_create_file(&interface->dev, &dev_attr_button);
  	if (retval)
  		goto error;
  	retval = device_create_file(&interface->dev, &dev_attr_port0);
  	if (retval)
  		goto error;
  	retval = device_create_file(&interface->dev, &dev_attr_port1);
  	if (retval)
  		goto error;
  
  	dev_info (&interface->dev,
  		  "Cypress thermometer device now attached\n");
  	return 0;
  error:
  	device_remove_file(&interface->dev, &dev_attr_brightness);
  	device_remove_file(&interface->dev, &dev_attr_temp);
  	device_remove_file(&interface->dev, &dev_attr_button);
  	device_remove_file(&interface->dev, &dev_attr_port0);
  	device_remove_file(&interface->dev, &dev_attr_port1);
  	usb_set_intfdata (interface, NULL);
  	usb_put_dev(dev->udev);
  	kfree(dev);
  error_mem:
  	return retval;
  }
  
  static void cytherm_disconnect(struct usb_interface *interface)
  {
  	struct usb_cytherm *dev;
  
  	dev = usb_get_intfdata (interface);
  
  	device_remove_file(&interface->dev, &dev_attr_brightness);
  	device_remove_file(&interface->dev, &dev_attr_temp);
  	device_remove_file(&interface->dev, &dev_attr_button);
  	device_remove_file(&interface->dev, &dev_attr_port0);
  	device_remove_file(&interface->dev, &dev_attr_port1);
  
  	/* first remove the files, then NULL the pointer */
  	usb_set_intfdata (interface, NULL);
  
  	usb_put_dev(dev->udev);
  
  	kfree(dev);
  
  	dev_info(&interface->dev, "Cypress thermometer now disconnected\n");
  }
  
  module_usb_driver(cytherm_driver);
  
  MODULE_AUTHOR(DRIVER_AUTHOR);
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");
  