staging: comedi: usbdux: use comedi_subdevice 'readback'

Use the new comedi_subdevice 'readback' member and the core provided
(*insn_read) for the readback of the analog output subdevice channels.

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

diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c
index ad0faf5..184dee2 100644 (file)
--- a/drivers/staging/comedi/drivers/usbdux.c
+++ b/drivers/staging/comedi/drivers/usbdux.c
@@ -109,8 +109,6 @@ sampling rate. If you sample two channels you get 4kHz and so on.
 #define USBDUX_CMD_PWM_ON      7
 #define USBDUX_CMD_PWM_OFF     8
 
-#define USBDUX_NUM_AO_CHAN     4
-
 /* timeout for the USB-transfer in ms */
 #define BULK_TIMEOUT           1000
 
@@ -202,8 +200,6 @@ struct usbdux_private {
        /* input buffer for single insn */
        uint16_t *insn_buf;
 
-       unsigned int ao_readback[USBDUX_NUM_AO_CHAN];
-
        unsigned int high_speed:1;
        unsigned int ai_cmd_running:1;
        unsigned int ao_cmd_running:1;
@@ -490,7 +486,7 @@ static void usbduxsub_ao_isoc_irq(struct urb *urb)
                        *datap++ = val & 0xff;
                        *datap++ = (val >> 8) & 0xff;
                        *datap++ = chan << 6;
-                       devpriv->ao_readback[chan] = val;
+                       s->readback[chan] = val;
 
                        s->async->events |= COMEDI_CB_BLOCK;
                        comedi_event(dev, s);
@@ -855,15 +851,13 @@ static int usbdux_ao_insn_read(struct comedi_device *dev,
                               unsigned int *data)
 {
        struct usbdux_private *devpriv = dev->private;
-       unsigned int chan = CR_CHAN(insn->chanspec);
-       int i;
+       int ret;
 
        down(&devpriv->sem);
-       for (i = 0; i < insn->n; i++)
-               data[i] = devpriv->ao_readback[chan];
+       ret = comedi_readback_insn_read(dev, s, insn, data);
        up(&devpriv->sem);
 
-       return insn->n;
+       return ret;
 }
 
 static int usbdux_ao_insn_write(struct comedi_device *dev,
@@ -873,7 +867,7 @@ static int usbdux_ao_insn_write(struct comedi_device *dev,
 {
        struct usbdux_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(insn->chanspec);
-       unsigned int val = devpriv->ao_readback[chan];
+       unsigned int val = s->readback[chan];
        uint16_t *p = (uint16_t *)&devpriv->dux_commands[2];
        int ret = -EBUSY;
        int i;
@@ -897,8 +891,9 @@ static int usbdux_ao_insn_write(struct comedi_device *dev,
                ret = send_dux_commands(dev, USBDUX_CMD_AO);
                if (ret < 0)
                        goto ao_write_exit;
+
+               s->readback[chan] = val;
        }
-       devpriv->ao_readback[chan] = val;
 
 ao_write_exit:
        up(&devpriv->sem);
@@ -1720,7 +1715,7 @@ static int usbdux_auto_attach(struct comedi_device *dev,
        dev->write_subdev = s;
        s->type         = COMEDI_SUBD_AO;
        s->subdev_flags = SDF_WRITABLE | SDF_GROUND | SDF_CMD_WRITE;
-       s->n_chan       = USBDUX_NUM_AO_CHAN;
+       s->n_chan       = 4;
        s->maxdata      = 0x0fff;
        s->len_chanlist = s->n_chan;
        s->range_table  = &range_usbdux_ao_range;
@@ -1730,6 +1725,10 @@ static int usbdux_auto_attach(struct comedi_device *dev,
        s->insn_read    = usbdux_ao_insn_read;
        s->insn_write   = usbdux_ao_insn_write;
 
+       ret = comedi_alloc_subdev_readback(s);
+       if (ret)
+               return ret;
+
        /* Digital I/O subdevice */
        s = &dev->subdevices[2];
        s->type         = COMEDI_SUBD_DIO;