// 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;
};


/* 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 brightness_show(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 brightness_store(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_RW(brightness);


#define TEMP 0x33 /* RAM location for temperature */
#define SIGN 0x34 /* RAM location for temperature sign */

static ssize_t temp_show(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 DEVICE_ATTR_RO(temp);


#define BUTTON 0x7a

static ssize_t button_show(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 DEVICE_ATTR_RO(button);


static ssize_t port0_show(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 port0_store(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_RW(port0);

static ssize_t port1_show(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 port1_store(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_RW(port1);

static struct attribute *cytherm_attrs[] = {
        &dev_attr_brightness.attr,
        &dev_attr_temp.attr,
        &dev_attr_button.attr,
        &dev_attr_port0.attr,
        &dev_attr_port1.attr,
        NULL,
};
ATTRIBUTE_GROUPS(cytherm);

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;
        int retval = -ENOMEM;

        dev = kzalloc_obj(struct usb_cytherm);
        if (!dev)
                goto error_mem;

        dev->udev = usb_get_dev(udev);

        usb_set_intfdata(interface, dev);

        dev->brightness = 0xFF;

        dev_info(&interface->dev,
                  "Cypress thermometer device now attached\n");
        return 0;

error_mem:
        return retval;
}

static void cytherm_disconnect(struct usb_interface *interface)
{
        struct usb_cytherm *dev;

        dev = usb_get_intfdata(interface);

        /* 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");
}

/* 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,
        .dev_groups =   cytherm_groups,
};

module_usb_driver(cytherm_driver);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");