powermate.c

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/*
 * A driver for the Griffin Technology, Inc. "PowerMate" USB controller dial.
 *
 * v1.1, (c)2002 William R Sowerbutts <[email protected]>
 *
 * This device is a anodised aluminium knob which connects over USB. It can measure
 * clockwise and anticlockwise rotation. The dial also acts as a pushbutton with
 * a spring for automatic release. The base contains a pair of LEDs which illuminate
 * the translucent base. It rotates without limit and reports its relative rotation
 * back to the host when polled by the USB controller.
 *
 * Testing with the knob I have has shown that it measures approximately 94 "clicks"
 * for one full rotation. Testing with my High Speed Rotation Actuator (ok, it was
 * a variable speed cordless electric drill) has shown that the device can measure
 * speeds of up to 7 clicks either clockwise or anticlockwise between pollings from
 * the host. If it counts more than 7 clicks before it is polled, it will wrap back
 * to zero and start counting again. This was at quite high speed, however, almost
 * certainly faster than the human hand could turn it. Griffin say that it loses a
 * pulse or two on a direction change; the granularity is so fine that I never
 * noticed this in practice.
 *
 * The device's microcontroller can be programmed to set the LED to either a constant
 * intensity, or to a rhythmic pulsing. Several patterns and speeds are available.
 *
 * Griffin were very happy to provide documentation and free hardware for development.
 *
 * Some userspace tools are available on the web: http://sowerbutts.com/powermate/
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/usb/input.h>

#define POWERMATE_VENDOR    0x077d  /* Griffin Technology, Inc. */
#define POWERMATE_PRODUCT_NEW   0x0410  /* Griffin PowerMate */
#define POWERMATE_PRODUCT_OLD   0x04AA  /* Griffin soundKnob */

#define CONTOUR_VENDOR      0x05f3  /* Contour Design, Inc. */
#define CONTOUR_JOG     0x0240  /* Jog and Shuttle */

/* these are the command codes we send to the device */
#define SET_STATIC_BRIGHTNESS  0x01
#define SET_PULSE_ASLEEP       0x02
#define SET_PULSE_AWAKE        0x03
#define SET_PULSE_MODE         0x04

/* these refer to bits in the powermate_device's requires_update field. */
#define UPDATE_STATIC_BRIGHTNESS (1<<0)
#define UPDATE_PULSE_ASLEEP      (1<<1)
#define UPDATE_PULSE_AWAKE       (1<<2)
#define UPDATE_PULSE_MODE        (1<<3)

/* at least two versions of the hardware exist, with differing payload
   sizes. the first three bytes always contain the "interesting" data in
   the relevant format. */
#define POWERMATE_PAYLOAD_SIZE_MAX 6
#define POWERMATE_PAYLOAD_SIZE_MIN 3
struct powermate_device {
    signed char *data;
    dma_addr_t data_dma;
    struct urb *irq, *config;
    struct usb_ctrlrequest *configcr;
    struct usb_device *udev;
    struct usb_interface *intf;
    struct input_dev *input;
    spinlock_t lock;
    int static_brightness;
    int pulse_speed;
    int pulse_table;
    int pulse_asleep;
    int pulse_awake;
    int requires_update; // physical settings which are out of sync
    char phys[64];
};

static char pm_name_powermate[] = "Griffin PowerMate";
static char pm_name_soundknob[] = "Griffin SoundKnob";

static void powermate_config_complete(struct urb *urb);

/* Callback for data arriving from the PowerMate over the USB interrupt pipe */
static void powermate_irq(struct urb *urb)
{
    struct powermate_device *pm = urb->context;
    struct device *dev = &pm->intf->dev;
    int retval;

    switch (urb->status) {
    case 0:
        /* success */
        break;
    case -ECONNRESET:
    case -ENOENT:
    case -ESHUTDOWN:
        /* this urb is terminated, clean up */
        dev_dbg(dev, "%s - urb shutting down with status: %d\n",
            __func__, urb->status);
        return;
    default:
        dev_dbg(dev, "%s - nonzero urb status received: %d\n",
            __func__, urb->status);
        goto exit;
    }

    /* handle updates to device state */
    input_report_key(pm->input, BTN_0, pm->data[0] & 0x01);
    input_report_rel(pm->input, REL_DIAL, pm->data[1]);
    input_sync(pm->input);

exit:
    retval = usb_submit_urb (urb, GFP_ATOMIC);
    if (retval)
        dev_err(dev, "%s - usb_submit_urb failed with result: %d\n",
            __func__, retval);
}

/* Decide if we need to issue a control message and do so. Must be called with pm->lock taken */
static void powermate_sync_state(struct powermate_device *pm)
{
    if (pm->requires_update == 0)
        return; /* no updates are required */
    if (pm->config->status == -EINPROGRESS)
        return; /* an update is already in progress; it'll issue this update when it completes */

    if (pm->requires_update & UPDATE_PULSE_ASLEEP){
        pm->configcr->wValue = cpu_to_le16( SET_PULSE_ASLEEP );
        pm->configcr->wIndex = cpu_to_le16( pm->pulse_asleep ? 1 : 0 );
        pm->requires_update &= ~UPDATE_PULSE_ASLEEP;
    }else if (pm->requires_update & UPDATE_PULSE_AWAKE){
        pm->configcr->wValue = cpu_to_le16( SET_PULSE_AWAKE );
        pm->configcr->wIndex = cpu_to_le16( pm->pulse_awake ? 1 : 0 );
        pm->requires_update &= ~UPDATE_PULSE_AWAKE;
    }else if (pm->requires_update & UPDATE_PULSE_MODE){
        int op, arg;
        /* the powermate takes an operation and an argument for its pulse algorithm.
           the operation can be:
           0: divide the speed
           1: pulse at normal speed
           2: multiply the speed
           the argument only has an effect for operations 0 and 2, and ranges between
           1 (least effect) to 255 (maximum effect).

           thus, several states are equivalent and are coalesced into one state.

           we map this onto a range from 0 to 510, with:
           0 -- 254    -- use divide (0 = slowest)
           255         -- use normal speed
           256 -- 510  -- use multiple (510 = fastest).

           Only values of 'arg' quite close to 255 are particularly useful/spectacular.
        */
        if (pm->pulse_speed < 255) {
            op = 0;                   // divide
            arg = 255 - pm->pulse_speed;
        } else if (pm->pulse_speed > 255) {
            op = 2;                   // multiply
            arg = pm->pulse_speed - 255;
        } else {
            op = 1;                   // normal speed
            arg = 0;                  // can be any value
        }
        pm->configcr->wValue = cpu_to_le16( (pm->pulse_table << 8) | SET_PULSE_MODE );
        pm->configcr->wIndex = cpu_to_le16( (arg << 8) | op );
        pm->requires_update &= ~UPDATE_PULSE_MODE;
    } else if (pm->requires_update & UPDATE_STATIC_BRIGHTNESS) {
        pm->configcr->wValue = cpu_to_le16( SET_STATIC_BRIGHTNESS );
        pm->configcr->wIndex = cpu_to_le16( pm->static_brightness );
        pm->requires_update &= ~UPDATE_STATIC_BRIGHTNESS;
    } else {
        printk(KERN_ERR "powermate: unknown update required");
        pm->requires_update = 0; /* fudge the bug */
        return;
    }

/*  printk("powermate: %04x %04x\n", pm->configcr->wValue, pm->configcr->wIndex); */

    pm->configcr->bRequestType = 0x41; /* vendor request */
    pm->configcr->bRequest = 0x01;
    pm->configcr->wLength = 0;

    usb_fill_control_urb(pm->config, pm->udev, usb_sndctrlpipe(pm->udev, 0),
                 (void *) pm->configcr, NULL, 0,
                 powermate_config_complete, pm);

    if (usb_submit_urb(pm->config, GFP_ATOMIC))
        printk(KERN_ERR "powermate: usb_submit_urb(config) failed");
}

/* Called when our asynchronous control message completes. We may need to issue another immediately */
static void powermate_config_complete(struct urb *urb)
{
    struct powermate_device *pm = urb->context;
    unsigned long flags;

    if (urb->status)
        printk(KERN_ERR "powermate: config urb returned %d\n", urb->status);

    spin_lock_irqsave(&pm->lock, flags);
    powermate_sync_state(pm);
    spin_unlock_irqrestore(&pm->lock, flags);
}

/* Set the LED up as described and begin the sync with the hardware if required */
static void powermate_pulse_led(struct powermate_device *pm, int static_brightness, int pulse_speed,
                int pulse_table, int pulse_asleep, int pulse_awake)
{
    unsigned long flags;

    if (pulse_speed < 0)
        pulse_speed = 0;
    if (pulse_table < 0)
        pulse_table = 0;
    if (pulse_speed > 510)
        pulse_speed = 510;
    if (pulse_table > 2)
        pulse_table = 2;

    pulse_asleep = !!pulse_asleep;
    pulse_awake = !!pulse_awake;


    spin_lock_irqsave(&pm->lock, flags);

    /* mark state updates which are required */
    if (static_brightness != pm->static_brightness) {
        pm->static_brightness = static_brightness;
        pm->requires_update |= UPDATE_STATIC_BRIGHTNESS;
    }
    if (pulse_asleep != pm->pulse_asleep) {
        pm->pulse_asleep = pulse_asleep;
        pm->requires_update |= (UPDATE_PULSE_ASLEEP | UPDATE_STATIC_BRIGHTNESS);
    }
    if (pulse_awake != pm->pulse_awake) {
        pm->pulse_awake = pulse_awake;
        pm->requires_update |= (UPDATE_PULSE_AWAKE | UPDATE_STATIC_BRIGHTNESS);
    }
    if (pulse_speed != pm->pulse_speed || pulse_table != pm->pulse_table) {
        pm->pulse_speed = pulse_speed;
        pm->pulse_table = pulse_table;
        pm->requires_update |= UPDATE_PULSE_MODE;
    }

    powermate_sync_state(pm);

    spin_unlock_irqrestore(&pm->lock, flags);
}

/* Callback from the Input layer when an event arrives from userspace to configure the LED */
static int powermate_input_event(struct input_dev *dev, unsigned int type, unsigned int code, int _value)
{
    unsigned int command = (unsigned int)_value;
    struct powermate_device *pm = input_get_drvdata(dev);

    if (type == EV_MSC && code == MSC_PULSELED){
        /*
            bits  0- 7: 8 bits: LED brightness
            bits  8-16: 9 bits: pulsing speed modifier (0 ... 510); 0-254 = slower, 255 = standard, 256-510 = faster.
            bits 17-18: 2 bits: pulse table (0, 1, 2 valid)
            bit     19: 1 bit : pulse whilst asleep?
            bit     20: 1 bit : pulse constantly?
        */
        int static_brightness = command & 0xFF;   // bits 0-7
        int pulse_speed = (command >> 8) & 0x1FF; // bits 8-16
        int pulse_table = (command >> 17) & 0x3;  // bits 17-18
        int pulse_asleep = (command >> 19) & 0x1; // bit 19
        int pulse_awake  = (command >> 20) & 0x1; // bit 20

        powermate_pulse_led(pm, static_brightness, pulse_speed, pulse_table, pulse_asleep, pulse_awake);
    }

    return 0;
}

static int powermate_alloc_buffers(struct usb_device *udev, struct powermate_device *pm)
{
    pm->data = usb_alloc_coherent(udev, POWERMATE_PAYLOAD_SIZE_MAX,
                      GFP_ATOMIC, &pm->data_dma);
    if (!pm->data)
        return -1;

    pm->configcr = kmalloc(sizeof(*(pm->configcr)), GFP_KERNEL);
    if (!pm->configcr)
        return -ENOMEM;

    return 0;
}

static void powermate_free_buffers(struct usb_device *udev, struct powermate_device *pm)
{
    usb_free_coherent(udev, POWERMATE_PAYLOAD_SIZE_MAX,
              pm->data, pm->data_dma);
    kfree(pm->configcr);
}

/* Called whenever a USB device matching one in our supported devices table is connected */
static int powermate_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
    struct usb_device *udev = interface_to_usbdev (intf);
    struct usb_host_interface *interface;
    struct usb_endpoint_descriptor *endpoint;
    struct powermate_device *pm;
    struct input_dev *input_dev;
    int pipe, maxp;
    int error = -ENOMEM;

    interface = intf->cur_altsetting;
    endpoint = &interface->endpoint[0].desc;
    if (!usb_endpoint_is_int_in(endpoint))
        return -EIO;

    usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
        0x0a, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
        0, interface->desc.bInterfaceNumber, NULL, 0,
        USB_CTRL_SET_TIMEOUT);

    pm = kzalloc(sizeof(struct powermate_device), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!pm || !input_dev)
        goto fail1;

    if (powermate_alloc_buffers(udev, pm))
        goto fail2;

    pm->irq = usb_alloc_urb(0, GFP_KERNEL);
    if (!pm->irq)
        goto fail2;

    pm->config = usb_alloc_urb(0, GFP_KERNEL);
    if (!pm->config)
        goto fail3;

    pm->udev = udev;
    pm->intf = intf;
    pm->input = input_dev;

    usb_make_path(udev, pm->phys, sizeof(pm->phys));
    strlcat(pm->phys, "/input0", sizeof(pm->phys));

    spin_lock_init(&pm->lock);

    switch (le16_to_cpu(udev->descriptor.idProduct)) {
    case POWERMATE_PRODUCT_NEW:
        input_dev->name = pm_name_powermate;
        break;
    case POWERMATE_PRODUCT_OLD:
        input_dev->name = pm_name_soundknob;
        break;
    default:
        input_dev->name = pm_name_soundknob;
        printk(KERN_WARNING "powermate: unknown product id %04x\n",
               le16_to_cpu(udev->descriptor.idProduct));
    }

    input_dev->phys = pm->phys;
    usb_to_input_id(udev, &input_dev->id);
    input_dev->dev.parent = &intf->dev;

    input_set_drvdata(input_dev, pm);

    input_dev->event = powermate_input_event;

    input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL) |
        BIT_MASK(EV_MSC);
    input_dev->keybit[BIT_WORD(BTN_0)] = BIT_MASK(BTN_0);
    input_dev->relbit[BIT_WORD(REL_DIAL)] = BIT_MASK(REL_DIAL);
    input_dev->mscbit[BIT_WORD(MSC_PULSELED)] = BIT_MASK(MSC_PULSELED);

    /* get a handle to the interrupt data pipe */
    pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);
    maxp = usb_maxpacket(udev, pipe, usb_pipeout(pipe));

    if (maxp < POWERMATE_PAYLOAD_SIZE_MIN || maxp > POWERMATE_PAYLOAD_SIZE_MAX) {
        printk(KERN_WARNING "powermate: Expected payload of %d--%d bytes, found %d bytes!\n",
            POWERMATE_PAYLOAD_SIZE_MIN, POWERMATE_PAYLOAD_SIZE_MAX, maxp);
        maxp = POWERMATE_PAYLOAD_SIZE_MAX;
    }

    usb_fill_int_urb(pm->irq, udev, pipe, pm->data,
             maxp, powermate_irq,
             pm, endpoint->bInterval);
    pm->irq->transfer_dma = pm->data_dma;
    pm->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

    /* register our interrupt URB with the USB system */
    if (usb_submit_urb(pm->irq, GFP_KERNEL)) {
        error = -EIO;
        goto fail4;
    }

    error = input_register_device(pm->input);
    if (error)
        goto fail5;


    /* force an update of everything */
    pm->requires_update = UPDATE_PULSE_ASLEEP | UPDATE_PULSE_AWAKE | UPDATE_PULSE_MODE | UPDATE_STATIC_BRIGHTNESS;
    powermate_pulse_led(pm, 0x80, 255, 0, 1, 0); // set default pulse parameters

    usb_set_intfdata(intf, pm);
    return 0;

 fail5: usb_kill_urb(pm->irq);
 fail4: usb_free_urb(pm->config);
 fail3: usb_free_urb(pm->irq);
 fail2: powermate_free_buffers(udev, pm);
 fail1: input_free_device(input_dev);
    kfree(pm);
    return error;
}

/* Called when a USB device we've accepted ownership of is removed */
static void powermate_disconnect(struct usb_interface *intf)
{
    struct powermate_device *pm = usb_get_intfdata (intf);

    usb_set_intfdata(intf, NULL);
    if (pm) {
        pm->requires_update = 0;
        usb_kill_urb(pm->irq);
        input_unregister_device(pm->input);
        usb_free_urb(pm->irq);
        usb_free_urb(pm->config);
        powermate_free_buffers(interface_to_usbdev(intf), pm);

        kfree(pm);
    }
}

static struct usb_device_id powermate_devices [] = {
    { USB_DEVICE(POWERMATE_VENDOR, POWERMATE_PRODUCT_NEW) },
    { USB_DEVICE(POWERMATE_VENDOR, POWERMATE_PRODUCT_OLD) },
    { USB_DEVICE(CONTOUR_VENDOR, CONTOUR_JOG) },
    { } /* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, powermate_devices);

static struct usb_driver powermate_driver = {
        .name =         "powermate",
        .probe =        powermate_probe,
        .disconnect =   powermate_disconnect,
        .id_table =     powermate_devices,
};

module_usb_driver(powermate_driver);

MODULE_AUTHOR( "William R Sowerbutts" );
MODULE_DESCRIPTION( "Griffin Technology, Inc PowerMate driver" );
MODULE_LICENSE("GPL");