staging: comedi: ni_65xx: remove 'output_bits' from private data

Remove the need for the 'output_bits' in the private data by just
reading the current state of the data port when updating the output
channels in the (*insn_bits) function.

Add a local variable to handle the inverting of the hardware values
when the boardinfo indicates that the outputs are inverted.

Rename the local variable 'port_read_bits' to 'bits' so that we can
use it for updating the output channels and reading back the actual
state to return to the user.

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/ni_65xx.c b/drivers/staging/comedi/drivers/ni_65xx.c
index 46d4ebcac55f3b99cdb8a8d11c004091e45bf120..a6d5fde428d601888423b46bdb3ed26186ad4759 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_65xx.c
+++ b/drivers/staging/comedi/drivers/ni_65xx.c
@@ -129,7 +129,6 @@
 #define NI_65XX_WDOG_HI_LO_REG(x)      (0x48 + NI_65XX_PORT(x))
 #define NI_65XX_RTSI_ENA(x)            (0x49 + NI_65XX_PORT(x))
 
-#define NI_65XX_MAX_NUM_PORTS          12
 #define NI_65XX_PORT_TO_CHAN(x)                ((x) * 8)
 #define NI_65XX_CHAN_TO_PORT(x)                ((x) / 8)
 #define NI_65XX_CHAN_TO_MASK(x)                (1 << ((x) % 8))
@@ -287,7 +286,6 @@ static inline unsigned ni_65xx_total_num_ports(const struct ni_65xx_board
 
 struct ni_65xx_private {
        void __iomem *mmio;
-       unsigned short output_bits[NI_65XX_MAX_NUM_PORTS];
 };
 
 static int ni_65xx_dio_insn_config(struct comedi_device *dev,
@@ -369,14 +367,19 @@ static int ni_65xx_dio_insn_bits(struct comedi_device *dev,
        unsigned long base_port = (unsigned long)s->private;
        unsigned int base_chan = CR_CHAN(insn->chanspec);
        int last_port_offset = NI_65XX_CHAN_TO_PORT(s->n_chan - 1);
+       unsigned invert = 0x00;
        unsigned read_bits = 0;
        int port_offset;
 
+       /* handle inverted outputs if necessary */
+       if (s->type == COMEDI_SUBD_DO && board->invert_outputs)
+               invert = 0xff;
+
        for (port_offset = NI_65XX_CHAN_TO_PORT(base_chan);
             port_offset <= last_port_offset; port_offset++) {
                unsigned port = base_port + port_offset;
                int base_port_channel = NI_65XX_PORT_TO_CHAN(port_offset);
-               unsigned port_mask, port_data, port_read_bits;
+               unsigned port_mask, port_data, bits;
                int bitshift = base_port_channel - base_chan;
 
                if (bitshift >= 32)
@@ -392,30 +395,26 @@ static int ni_65xx_dio_insn_bits(struct comedi_device *dev,
                }
                port_mask &= 0xff;
                port_data &= 0xff;
+
+               /* update the outputs */
                if (port_mask) {
-                       unsigned bits;
-                       devpriv->output_bits[port] &= ~port_mask;
-                       devpriv->output_bits[port] |=
-                           port_data & port_mask;
-                       bits = devpriv->output_bits[port];
-                       if (board->invert_outputs)
-                               bits = ~bits;
+                       bits = readb(devpriv->mmio + NI_65XX_IO_DATA_REG(port));
+                       bits ^= invert;
+                       bits &= ~port_mask;
+                       bits |= (port_data & port_mask);
+                       bits ^= invert;
                        writeb(bits, devpriv->mmio + NI_65XX_IO_DATA_REG(port));
                }
-               port_read_bits = readb(devpriv->mmio +
-                                      NI_65XX_IO_DATA_REG(port));
-               if (s->type == COMEDI_SUBD_DO && board->invert_outputs) {
-                       /* Outputs inverted, so invert value read back from
-                        * DO subdevice.  (Does not apply to boards with DIO
-                        * subdevice.) */
-                       port_read_bits ^= 0xFF;
-               }
+
+               /* read back the actual state */
+               bits = readb(devpriv->mmio + NI_65XX_IO_DATA_REG(port));
+               bits ^= invert;
                if (bitshift > 0)
-                       port_read_bits <<= bitshift;
+                       bits <<= bitshift;
                else
-                       port_read_bits >>= -bitshift;
+                       bits >>= -bitshift;
 
-               read_bits |= port_read_bits;
+               read_bits |= bits;
        }
        data[1] = read_bits;
        return insn->n;