usbsevseg.c

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/*
 * USB 7 Segment Driver
 *
 * Copyright (C) 2008 Harrison Metzger <[email protected]>
 * Based on usbled.c by Greg Kroah-Hartman ([email protected])
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as
 *  published by the Free Software Foundation, version 2.
 *
 */

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


#define DRIVER_AUTHOR "Harrison Metzger <[email protected]>"
#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 char *display_textmodes[] = {"raw", "hex", "ascii", NULL};

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.
 */
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(mydev->udev,
            usb_sndctrlpipe(mydev->udev, 0),
            0x12,
            0x48,
            (80 * 0x100) + 10, /*  (power mode) */
            (0x00 * 0x100) + (mydev->powered ? 1 : 0),
            NULL,
            0,
            2000);
    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(mydev->udev,
            usb_sndctrlpipe(mydev->udev, 0),
            0x12,
            0x48,
            (82 * 0x100) + 10, /* (set mode) */
            (mydev->mode_msb * 0x100) + mydev->mode_lsb,
            NULL,
            0,
            2000);

    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;
    u8 decimals = 0;

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

    buffer = kzalloc(MAXLEN, mf);
    if (!buffer) {
        dev_err(&mydev->udev->dev, "out of memory\n");
        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(mydev->udev,
            usb_sndctrlpipe(mydev->udev, 0),
            0x12,
            0x48,
            (85 * 0x100) + 10, /* (write text) */
            (0 * 0x100) + mydev->textmode, /* mode  */
            buffer,
            mydev->textlength,
            2000);

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

    kfree(buffer);

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

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

#define MYDEV_ATTR_SIMPLE_UNSIGNED(name, update_fcn)        \
static ssize_t show_attr_##name(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 set_attr_##name(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(name, S_IRUGO | S_IWUSR, show_attr_##name, set_attr_##name);

static ssize_t show_attr_text(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 snprintf(buf, mydev->textlength, "%s\n", mydev->text);
}

static ssize_t set_attr_text(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(text, S_IRUGO | S_IWUSR, show_attr_text, set_attr_text);

static ssize_t show_attr_decimals(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 set_attr_decimals(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(decimals, S_IRUGO | S_IWUSR, show_attr_decimals, set_attr_decimals);

static ssize_t show_attr_textmode(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; display_textmodes[i]; 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 set_attr_textmode(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;

    for (i = 0; display_textmodes[i]; i++) {
        if (sysfs_streq(display_textmodes[i], buf)) {
            mydev->textmode = i;
            update_display_visual(mydev, GFP_KERNEL);
            return count;
        }
    }

    return -EINVAL;
}

static DEVICE_ATTR(textmode, S_IRUGO | S_IWUSR, show_attr_textmode, set_attr_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 *dev_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
};

static struct attribute_group dev_attr_grp = {
    .attrs = dev_attrs,
};

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 = NULL;
    int rc = -ENOMEM;

    mydev = kzalloc(sizeof(struct usb_sevsegdev), GFP_KERNEL);
    if (mydev == NULL) {
        dev_err(&interface->dev, "Out of memory\n");
        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 */

    rc = sysfs_create_group(&interface->dev.kobj, &dev_attr_grp);
    if (rc)
        goto error;

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

error:
    usb_set_intfdata(interface, NULL);
    usb_put_dev(mydev->udev);
    kfree(mydev);
error_mem:
    return rc;
}

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

    mydev = usb_get_intfdata(interface);
    sysfs_remove_group(&interface->dev.kobj, &dev_attr_grp);
    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,
    .supports_autosuspend = 1,
};

module_usb_driver(sevseg_driver);

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