staging: comedi: comedi_parport: remove 'c_data' from private data

The control register for the parallel port is readable so there is no need
to cache the current value in the private data.

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/comedi_parport.c b/drivers/staging/comedi/drivers/comedi_parport.c
index d720f27..6d8fb29 100644 (file)
--- a/drivers/staging/comedi/drivers/comedi_parport.c
+++ b/drivers/staging/comedi/drivers/comedi_parport.c
@@ -92,7 +92,6 @@ pin, which can be used to wake up tasks.
 #define PARPORT_CTRL_BIDIR_ENA (1 << 5)
 
 struct parport_private {
-       unsigned int c_data;
        int enable_irq;
 };
 
@@ -114,18 +113,19 @@ static int parport_data_reg_insn_config(struct comedi_device *dev,
                                        struct comedi_insn *insn,
                                        unsigned int *data)
 {
-       struct parport_private *devpriv = dev->private;
+       unsigned int ctrl;
        int ret;
 
        ret = comedi_dio_insn_config(dev, s, insn, data, 0xff);
        if (ret)
                return ret;
 
+       ctrl = inb(dev->iobase + PARPORT_CTRL_REG);
        if (s->io_bits)
-               devpriv->c_data &= ~PARPORT_CTRL_BIDIR_ENA;
+               ctrl &= ~PARPORT_CTRL_BIDIR_ENA;
        else
-               devpriv->c_data |= PARPORT_CTRL_BIDIR_ENA;
-       outb(devpriv->c_data, dev->iobase + PARPORT_CTRL_REG);
+               ctrl |= PARPORT_CTRL_BIDIR_ENA;
+       outb(ctrl, dev->iobase + PARPORT_CTRL_REG);
 
        return insn->n;
 }
@@ -145,12 +145,13 @@ static int parport_ctrl_reg_insn_bits(struct comedi_device *dev,
                                      struct comedi_insn *insn,
                                      unsigned int *data)
 {
-       struct parport_private *devpriv = dev->private;
+       unsigned int ctrl;
 
        if (comedi_dio_update_state(s, data)) {
-               devpriv->c_data &= ~((1 << s->n_chan) - 1);
-               devpriv->c_data |= s->state;
-               outb(devpriv->c_data, dev->iobase + PARPORT_CTRL_REG);
+               ctrl = inb(dev->iobase + PARPORT_CTRL_REG);
+               ctrl &= (PARPORT_CTRL_IRQ_ENA | PARPORT_CTRL_BIDIR_ENA);
+               ctrl |= s->state;
+               outb(ctrl, dev->iobase + PARPORT_CTRL_REG);
        }
 
        data[1] = s->state;
@@ -212,9 +213,11 @@ static int parport_intr_cmd(struct comedi_device *dev,
                            struct comedi_subdevice *s)
 {
        struct parport_private *devpriv = dev->private;
+       unsigned int ctrl;
 
-       devpriv->c_data |= PARPORT_CTRL_IRQ_ENA;
-       outb(devpriv->c_data, dev->iobase + PARPORT_CTRL_REG);
+       ctrl = inb(dev->iobase + PARPORT_CTRL_REG);
+       ctrl |= PARPORT_CTRL_IRQ_ENA;
+       outb(ctrl, dev->iobase + PARPORT_CTRL_REG);
 
        devpriv->enable_irq = 1;
 
@@ -225,9 +228,11 @@ static int parport_intr_cancel(struct comedi_device *dev,
                               struct comedi_subdevice *s)
 {
        struct parport_private *devpriv = dev->private;
+       unsigned int ctrl;
 
-       devpriv->c_data &= ~PARPORT_CTRL_IRQ_ENA;
-       outb(devpriv->c_data, dev->iobase + PARPORT_CTRL_REG);
+       ctrl = inb(dev->iobase + PARPORT_CTRL_REG);
+       ctrl &= ~PARPORT_CTRL_IRQ_ENA;
+       outb(ctrl, dev->iobase + PARPORT_CTRL_REG);
 
        devpriv->enable_irq = 0;
 
@@ -323,8 +328,7 @@ static int parport_attach(struct comedi_device *dev,
        }
 
        outb(0, dev->iobase + PARPORT_DATA_REG);
-       devpriv->c_data = 0;
-       outb(devpriv->c_data, dev->iobase + PARPORT_CTRL_REG);
+       outb(0, dev->iobase + PARPORT_CTRL_REG);
 
        return 0;
 }