// SPDX-License-Identifier: GPL-2.0
/*
 * USB 7 Segment Driver
 *
 * Copyright (C) 2008 Harrison Metzger <harrisonmetz@gmail.com>
 * Based on usbled.c by Greg Kroah-Hartman (greg@kroah.com)
 */

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


#define DRIVER_AUTHOR "Harrison Metzger <harrisonmetz@gmail.com>"
#define DRIVER_DESC "USB 7 Segment Driver"

#define VENDOR_ID       0x0fc5
#define PRODUCT_ID      0x1227
#define MAXLEN          8

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

/* the different text display modes the device is capable of */
static const char *display_textmodes[] = {"raw", "hex", "ascii"};

struct usb_sevsegdev {
        struct usb_device *udev;
        struct usb_interface *intf;

        u8 powered;
        u8 mode_msb;
        u8 mode_lsb;
        u8 decimals[MAXLEN];
        u8 textmode;
        u8 text[MAXLEN];
        u16 textlength;

        u8 shadow_power; /* for PM */
        u8 has_interface_pm;
};

/* sysfs_streq can't replace this completely
 * If the device was in hex mode, and the user wanted a 0,
 * if str commands are used, we would assume the end of string
 * so mem commands are used.
 */
static inline size_t my_memlen(const char *buf, size_t count)
{
        if (count > 0 && buf[count-1] == '\n')
                return count - 1;
        else
                return count;
}

static void update_display_powered(struct usb_sevsegdev *mydev)
{
        int rc;

        if (mydev->powered && !mydev->has_interface_pm) {
                rc = usb_autopm_get_interface(mydev->intf);
                if (rc < 0)
                        return;
                mydev->has_interface_pm = 1;
        }

        if (mydev->shadow_power != 1)
                return;

        rc = usb_control_msg_send(mydev->udev, 0, 0x12, 0x48,
                                  (80 * 0x100) + 10, /*  (power mode) */
                                  (0x00 * 0x100) + (mydev->powered ? 1 : 0),
                                  NULL, 0, 2000, GFP_KERNEL);
        if (rc < 0)
                dev_dbg(&mydev->udev->dev, "power retval = %d\n", rc);

        if (!mydev->powered && mydev->has_interface_pm) {
                usb_autopm_put_interface(mydev->intf);
                mydev->has_interface_pm = 0;
        }
}

static void update_display_mode(struct usb_sevsegdev *mydev)
{
        int rc;

        if(mydev->shadow_power != 1)
                return;

        rc = usb_control_msg_send(mydev->udev, 0, 0x12, 0x48,
                                  (82 * 0x100) + 10, /* (set mode) */
                                  (mydev->mode_msb * 0x100) + mydev->mode_lsb,
                                  NULL, 0, 2000, GFP_NOIO);

        if (rc < 0)
                dev_dbg(&mydev->udev->dev, "mode retval = %d\n", rc);
}

static void update_display_visual(struct usb_sevsegdev *mydev, gfp_t mf)
{
        int rc;
        int i;
        unsigned char buffer[MAXLEN] = {0};
        u8 decimals = 0;

        if(mydev->shadow_power != 1)
                return;

        /* The device is right to left, where as you write left to right */
        for (i = 0; i < mydev->textlength; i++)
                buffer[i] = mydev->text[mydev->textlength-1-i];

        rc = usb_control_msg_send(mydev->udev, 0, 0x12, 0x48,
                                  (85 * 0x100) + 10, /* (write text) */
                                  (0 * 0x100) + mydev->textmode, /* mode  */
                                  &buffer, mydev->textlength, 2000, mf);

        if (rc < 0)
                dev_dbg(&mydev->udev->dev, "write retval = %d\n", rc);

        /* The device is right to left, where as you write left to right */
        for (i = 0; i < sizeof(mydev->decimals); i++)
                decimals |= mydev->decimals[i] << i;

        rc = usb_control_msg_send(mydev->udev, 0, 0x12, 0x48,
                                  (86 * 0x100) + 10, /* (set decimal) */
                                  (0 * 0x100) + decimals, /* decimals */
                                  NULL, 0, 2000, mf);

        if (rc < 0)
                dev_dbg(&mydev->udev->dev, "decimal retval = %d\n", rc);
}

#define MYDEV_ATTR_SIMPLE_UNSIGNED(name, update_fcn)            \
static ssize_t name##_show(struct device *dev,                  \
        struct device_attribute *attr, char *buf)               \
{                                                               \
        struct usb_interface *intf = to_usb_interface(dev);     \
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);   \
                                                                \
        return sprintf(buf, "%u\n", mydev->name);               \
}                                                               \
                                                                \
static ssize_t name##_store(struct device *dev,                 \
        struct device_attribute *attr, const char *buf, size_t count) \
{                                                               \
        struct usb_interface *intf = to_usb_interface(dev);     \
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);   \
                                                                \
        mydev->name = simple_strtoul(buf, NULL, 10);            \
        update_fcn(mydev);                                      \
                                                                \
        return count;                                           \
}                                                               \
static DEVICE_ATTR_RW(name);

static ssize_t text_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);

        return sysfs_emit(buf, "%s\n", mydev->text);
}

static ssize_t text_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t count)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
        size_t end = my_memlen(buf, count);

        if (end > sizeof(mydev->text))
                return -EINVAL;

        memset(mydev->text, 0, sizeof(mydev->text));
        mydev->textlength = end;

        if (end > 0)
                memcpy(mydev->text, buf, end);

        update_display_visual(mydev, GFP_KERNEL);
        return count;
}

static DEVICE_ATTR_RW(text);

static ssize_t decimals_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
        int i;
        int pos;

        for (i = 0; i < sizeof(mydev->decimals); i++) {
                pos = sizeof(mydev->decimals) - 1 - i;
                if (mydev->decimals[i] == 0)
                        buf[pos] = '0';
                else if (mydev->decimals[i] == 1)
                        buf[pos] = '1';
                else
                        buf[pos] = 'x';
        }

        buf[sizeof(mydev->decimals)] = '\n';
        return sizeof(mydev->decimals) + 1;
}

static ssize_t decimals_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t count)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
        size_t end = my_memlen(buf, count);
        int i;

        if (end > sizeof(mydev->decimals))
                return -EINVAL;

        for (i = 0; i < end; i++)
                if (buf[i] != '0' && buf[i] != '1')
                        return -EINVAL;

        memset(mydev->decimals, 0, sizeof(mydev->decimals));
        for (i = 0; i < end; i++)
                if (buf[i] == '1')
                        mydev->decimals[end-1-i] = 1;

        update_display_visual(mydev, GFP_KERNEL);

        return count;
}

static DEVICE_ATTR_RW(decimals);

static ssize_t textmode_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
        int i;

        buf[0] = 0;

        for (i = 0; i < ARRAY_SIZE(display_textmodes); i++) {
                if (mydev->textmode == i) {
                        strcat(buf, " [");
                        strcat(buf, display_textmodes[i]);
                        strcat(buf, "] ");
                } else {
                        strcat(buf, " ");
                        strcat(buf, display_textmodes[i]);
                        strcat(buf, " ");
                }
        }
        strcat(buf, "\n");


        return strlen(buf);
}

static ssize_t textmode_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t count)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
        int i;

        i = sysfs_match_string(display_textmodes, buf);
        if (i < 0)
                return i;

        mydev->textmode = i;
        update_display_visual(mydev, GFP_KERNEL);
        return count;
}

static DEVICE_ATTR_RW(textmode);


MYDEV_ATTR_SIMPLE_UNSIGNED(powered, update_display_powered);
MYDEV_ATTR_SIMPLE_UNSIGNED(mode_msb, update_display_mode);
MYDEV_ATTR_SIMPLE_UNSIGNED(mode_lsb, update_display_mode);

static struct attribute *sevseg_attrs[] = {
        &dev_attr_powered.attr,
        &dev_attr_text.attr,
        &dev_attr_textmode.attr,
        &dev_attr_decimals.attr,
        &dev_attr_mode_msb.attr,
        &dev_attr_mode_lsb.attr,
        NULL
};
ATTRIBUTE_GROUPS(sevseg);

static int sevseg_probe(struct usb_interface *interface,
        const struct usb_device_id *id)
{
        struct usb_device *udev = interface_to_usbdev(interface);
        struct usb_sevsegdev *mydev;
        int rc = -ENOMEM;

        mydev = kzalloc_obj(struct usb_sevsegdev);
        if (!mydev)
                goto error_mem;

        mydev->udev = usb_get_dev(udev);
        mydev->intf = interface;
        usb_set_intfdata(interface, mydev);

        /* PM */
        mydev->shadow_power = 1; /* currently active */
        mydev->has_interface_pm = 0; /* have not issued autopm_get */

        /*set defaults */
        mydev->textmode = 0x02; /* ascii mode */
        mydev->mode_msb = 0x06; /* 6 characters */
        mydev->mode_lsb = 0x3f; /* scanmode for 6 chars */

        dev_info(&interface->dev, "USB 7 Segment device now attached\n");
        return 0;

error_mem:
        return rc;
}

static void sevseg_disconnect(struct usb_interface *interface)
{
        struct usb_sevsegdev *mydev;

        mydev = usb_get_intfdata(interface);
        usb_set_intfdata(interface, NULL);
        usb_put_dev(mydev->udev);
        kfree(mydev);
        dev_info(&interface->dev, "USB 7 Segment now disconnected\n");
}

static int sevseg_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct usb_sevsegdev *mydev;

        mydev = usb_get_intfdata(intf);
        mydev->shadow_power = 0;

        return 0;
}

static int sevseg_resume(struct usb_interface *intf)
{
        struct usb_sevsegdev *mydev;

        mydev = usb_get_intfdata(intf);
        mydev->shadow_power = 1;
        update_display_mode(mydev);
        update_display_visual(mydev, GFP_NOIO);

        return 0;
}

static int sevseg_reset_resume(struct usb_interface *intf)
{
        struct usb_sevsegdev *mydev;

        mydev = usb_get_intfdata(intf);
        mydev->shadow_power = 1;
        update_display_mode(mydev);
        update_display_visual(mydev, GFP_NOIO);

        return 0;
}

static struct usb_driver sevseg_driver = {
        .name =         "usbsevseg",
        .probe =        sevseg_probe,
        .disconnect =   sevseg_disconnect,
        .suspend =      sevseg_suspend,
        .resume =       sevseg_resume,
        .reset_resume = sevseg_reset_resume,
        .id_table =     id_table,
        .dev_groups =   sevseg_groups,
        .supports_autosuspend = 1,
};

module_usb_driver(sevseg_driver);

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