staging: comedi: dt9812: remove attaching by serial number

Currently this driver supports attaching 16 usb devices to 16
comedi devices. The user can pass the 32-bit serial number of
the usb device when attaching to force a comedi device to attach
to a specific usb device.

It's also possible to attach a comedi device without having an
attached usb device. When the device is first opened the
comedi_device (*open) function in this driver then checks to
see if a usb device has been attached. If so the subdevice
information is updated based on the usb device and the comedi
device is then operational. If a usb device is not attached
the (*open) returns -ENODEV.

To simplify converting this driver to the comedi (*auto_attach)
mechanism, remove the attaching by serial number option.

Modify the usb (*probe) so that the first available slot is used.
If all the slots are used return -ENODEV.

Modify the comedi (*attach) so that the first unused slot that
has an attached usb device is used. If all the slots are used
return -ENODEV.

Since this ensures that the comedi device has an attached usb
device, remove the (*open) function and fully initialize the
subdevices during the (*attach).

Fix the comedi (*detach) so that the slot is made available
after detaching.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/dt9812.c b/drivers/staging/comedi/drivers/dt9812.c
index 1fda98c..b797517 100644 (file)
--- a/drivers/staging/comedi/drivers/dt9812.c
+++ b/drivers/staging/comedi/drivers/dt9812.c
@@ -281,12 +281,10 @@ struct usb_dt9812 {
 
 struct dt9812_private {
        struct slot_dt9812 *slot;
-       u32 serial;
 };
 
 struct slot_dt9812 {
        struct semaphore mutex;
-       u32 serial;
        struct usb_dt9812 *usb;
        struct dt9812_private *devpriv;
 };
@@ -654,63 +652,6 @@ static int dt9812_analog_out(struct slot_dt9812 *slot, int channel, u16 value)
        return result;
 }
 
-/*
- * Comedi functions
- */
-
-static int dt9812_comedi_open(struct comedi_device *dev)
-{
-       struct dt9812_private *devpriv = dev->private;
-       int result = -ENODEV;
-
-       down(&devpriv->slot->mutex);
-       if (devpriv->slot->usb) {
-               /* We have an attached device, fill in current range info */
-               struct comedi_subdevice *s;
-
-               s = &dev->subdevices[0];
-               s->n_chan = 8;
-               s->maxdata = 1;
-
-               s = &dev->subdevices[1];
-               s->n_chan = 8;
-               s->maxdata = 1;
-
-               s = &dev->subdevices[2];
-               s->n_chan = 8;
-               switch (devpriv->slot->usb->device) {
-               case 0:{
-                               s->maxdata = 4095;
-                               s->range_table = &range_bipolar10;
-                       }
-                       break;
-               case 1:{
-                               s->maxdata = 4095;
-                               s->range_table = &range_unipolar2_5;
-                       }
-                       break;
-               }
-
-               s = &dev->subdevices[3];
-               s->n_chan = 2;
-               switch (devpriv->slot->usb->device) {
-               case 0:{
-                               s->maxdata = 4095;
-                               s->range_table = &range_bipolar10;
-                       }
-                       break;
-               case 1:{
-                               s->maxdata = 4095;
-                               s->range_table = &range_unipolar2_5;
-                       }
-                       break;
-               }
-               result = 0;
-       }
-       up(&devpriv->slot->mutex);
-       return result;
-}
-
 static int dt9812_di_rinsn(struct comedi_device *dev,
                           struct comedi_subdevice *s, struct comedi_insn *insn,
                           unsigned int *data)
@@ -796,9 +737,11 @@ static int dt9812_ao_winsn(struct comedi_device *dev,
 
 static int dt9812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 {
+       struct slot_dt9812 *slot = NULL;
        struct dt9812_private *devpriv;
        int i;
        struct comedi_subdevice *s;
+       bool range_2_5;
        int ret;
 
        devpriv = kzalloc(sizeof(*devpriv), GFP_KERNEL);
@@ -806,13 +749,30 @@ static int dt9812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                return -ENOMEM;
        dev->private = devpriv;
 
+       down(&dt9812_mutex);
+
        /*
-        * Special open routine, since USB unit may be unattached at
-        * comedi_config time, hence range can not be determined
+        * Find the first unused slot for the comedi device
+        * that has a usb device connected.
         */
-       dev->open = dt9812_comedi_open;
+       for (i = 0; i < DT9812_NUM_SLOTS; i++) {
+               if (dt9812[i].usb && !dt9812[i].devpriv) {
+                       slot = &dt9812[i];
+                       break;
+               }
+       }
+       if (!slot) {
+               up(&dt9812_mutex);
+               return -ENODEV;
+       }
 
-       devpriv->serial = it->options[0];
+       down(&slot->mutex);
+       slot->devpriv = devpriv;
+       devpriv->slot = slot;
+       range_2_5 = (slot->usb->device == DT9812_DEVID_DT9812_2PT5);
+       up(&slot->mutex);
+
+       up(&dt9812_mutex);
 
        ret = comedi_alloc_subdevices(dev, 4);
        if (ret)
@@ -822,7 +782,7 @@ static int dt9812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s = &dev->subdevices[0];
        s->type = COMEDI_SUBD_DI;
        s->subdev_flags = SDF_READABLE;
-       s->n_chan = 0;
+       s->n_chan = 8;
        s->maxdata = 1;
        s->range_table = &range_digital;
        s->insn_read = &dt9812_di_rinsn;
@@ -831,7 +791,7 @@ static int dt9812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s = &dev->subdevices[1];
        s->type = COMEDI_SUBD_DO;
        s->subdev_flags = SDF_WRITEABLE;
-       s->n_chan = 0;
+       s->n_chan = 8;
        s->maxdata = 1;
        s->range_table = &range_digital;
        s->insn_write = &dt9812_do_winsn;
@@ -840,9 +800,9 @@ static int dt9812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s = &dev->subdevices[2];
        s->type = COMEDI_SUBD_AI;
        s->subdev_flags = SDF_READABLE | SDF_GROUND;
-       s->n_chan = 0;
-       s->maxdata = 1;
-       s->range_table = NULL;
+       s->n_chan = 8;
+       s->maxdata = 4095;
+       s->range_table = range_2_5 ? &range_unipolar2_5 : &range_bipolar10;
        s->insn_read = &dt9812_ai_rinsn;
 
        /* analog output subdevice */
@@ -850,48 +810,22 @@ static int dt9812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s->type = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITEABLE;
        s->n_chan = 0;
-       s->maxdata = 1;
-       s->range_table = NULL;
+       s->maxdata = 4095;
+       s->range_table = range_2_5 ? &range_unipolar2_5 : &range_bipolar10;
        s->insn_write = &dt9812_ao_winsn;
        s->insn_read = &dt9812_ao_rinsn;
 
        dev_info(dev->class_dev, "successfully attached to dt9812.\n");
 
-       down(&dt9812_mutex);
-       /* Find a slot for the comedi device */
-       {
-               struct slot_dt9812 *first = NULL;
-               struct slot_dt9812 *best = NULL;
-               for (i = 0; i < DT9812_NUM_SLOTS; i++) {
-                       if (!first && !dt9812[i].devpriv) {
-                               /* First free slot from comedi side */
-                               first = &dt9812[i];
-                       }
-                       if (!best &&
-                           dt9812[i].usb &&
-                           dt9812[i].usb->serial == devpriv->serial) {
-                               /* We have an attaced device with matching ID */
-                               best = &dt9812[i];
-                       }
-               }
-               if (!best)
-                       best = first;
-               if (best) {
-                       down(&best->mutex);
-                       best->devpriv = devpriv;
-                       best->serial = devpriv->serial;
-                       devpriv->slot = best;
-                       up(&best->mutex);
-               }
-       }
-       up(&dt9812_mutex);
-
        return 0;
 }
 
 static void dt9812_detach(struct comedi_device *dev)
 {
-       /* Nothing to cleanup */
+       struct dt9812_private *devpriv = dev->private;
+
+       if (devpriv && devpriv->slot)
+               devpriv->slot = NULL;
 }
 
 static struct comedi_driver dt9812_comedi_driver = {
@@ -904,10 +838,11 @@ static struct comedi_driver dt9812_comedi_driver = {
 static int dt9812_probe(struct usb_interface *interface,
                        const struct usb_device_id *id)
 {
-       int retval = -ENOMEM;
+       struct slot_dt9812 *slot = NULL;
        struct usb_dt9812 *dev = NULL;
        struct usb_host_interface *iface_desc;
        struct usb_endpoint_descriptor *endpoint;
+       int retval = -ENOMEM;
        int i;
        u8 fw;
 
@@ -918,6 +853,28 @@ static int dt9812_probe(struct usb_interface *interface,
 
        kref_init(&dev->kref);
 
+       down(&dt9812_mutex);
+
+       /* Find an empty slot for the usb device */
+       for (i = 0; i < DT9812_NUM_SLOTS; i++) {
+               if (!dt9812[i].usb) {
+                       slot = &dt9812[i];
+                       break;
+               }
+       }
+       if (!slot) {
+               up(&dt9812_mutex);
+               retval = -ENODEV;
+               goto error;
+       }
+
+       down(&slot->mutex);
+       slot->usb = dev;
+       dev->slot = slot;
+       up(&slot->mutex);
+
+       up(&dt9812_mutex);
+
        dev->udev = usb_get_dev(interface_to_usbdev(interface));
        dev->interface = interface;
 
@@ -1034,31 +991,6 @@ static int dt9812_probe(struct usb_interface *interface,
        dev_info(&interface->dev, "USB DT9812 (%4.4x.%4.4x.%4.4x) #0x%8.8x\n",
                 dev->vendor, dev->product, dev->device, dev->serial);
 
-       down(&dt9812_mutex);
-       {
-               /* Find a slot for the USB device */
-               struct slot_dt9812 *first = NULL;
-               struct slot_dt9812 *best = NULL;
-
-               for (i = 0; i < DT9812_NUM_SLOTS; i++) {
-                       if (!first && !dt9812[i].usb && dt9812[i].serial == 0)
-                               first = &dt9812[i];
-                       if (!best && dt9812[i].serial == dev->serial)
-                               best = &dt9812[i];
-               }
-
-               if (!best)
-                       best = first;
-
-               if (best) {
-                       down(&best->mutex);
-                       best->usb = dev;
-                       dev->slot = best;
-                       up(&best->mutex);
-               }
-       }
-       up(&dt9812_mutex);
-
        return 0;
 
 error:
@@ -1109,11 +1041,9 @@ static int __init usb_dt9812_init(void)
        /* Initialize all driver slots */
        for (i = 0; i < DT9812_NUM_SLOTS; i++) {
                sema_init(&dt9812[i].mutex, 1);
-               dt9812[i].serial = 0;
                dt9812[i].usb = NULL;
                dt9812[i].devpriv = NULL;
        }
-       dt9812[12].serial = 0x0;
 
        return comedi_usb_driver_register(&dt9812_comedi_driver,
                                                &dt9812_usb_driver);