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author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2013-06-18 13:25:47 -0700 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-24 15:51:04 -0700 |
commit | 1fdd0fc5fe28cd11ecf64e77892a1d9a1fd89fbf (patch) | |
tree | a36a21eb6305fefd410830cc195ddaf70fea5743 /drivers/staging/comedi | |
parent | 89aaa92adffa5c57d9c2a545c7cb9809ddd3b615 (diff) | |
download | linux-1fdd0fc5fe28cd11ecf64e77892a1d9a1fd89fbf.tar.gz linux-1fdd0fc5fe28cd11ecf64e77892a1d9a1fd89fbf.tar.bz2 linux-1fdd0fc5fe28cd11ecf64e77892a1d9a1fd89fbf.zip |
staging: comedi: pcmuio: cleanup DIO subdevice (*insn_{bits,config})
Use the pcmuio_{read,write}() helpers to read/write all 24 channels
instead of handling the digital I/O as three separate ports. This
simplifies both functions with minimal overhead.
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>
Diffstat (limited to 'drivers/staging/comedi')
-rw-r--r-- | drivers/staging/comedi/drivers/pcmuio.c | 104 |
1 files changed, 29 insertions, 75 deletions
diff --git a/drivers/staging/comedi/drivers/pcmuio.c b/drivers/staging/comedi/drivers/pcmuio.c index e52f6aeee453..d1f5fc024089 100644 --- a/drivers/staging/comedi/drivers/pcmuio.c +++ b/drivers/staging/comedi/drivers/pcmuio.c @@ -203,51 +203,42 @@ static unsigned int pcmuio_read(struct comedi_device *dev, return val; } +/* + * Each channel can be individually programmed for input or output. + * Writing a '0' to a channel causes the corresponding output pin + * to go to a high-z state (pulled high by an external 10K resistor). + * This allows it to be used as an input. When used in the input mode, + * a read reflects the inverted state of the I/O pin, such that a + * high on the pin will read as a '0' in the register. Writing a '1' + * to a bit position causes the pin to sink current (up to 12mA), + * effectively pulling it low. + */ static int pcmuio_dio_insn_bits(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { + unsigned int mask = data[0] & s->io_bits; /* outputs only */ + unsigned int bits = data[1]; int asic = s->index / 2; int port = (s->index % 2) ? 3 : 0; - unsigned long iobase = dev->iobase + (asic * ASIC_IOSIZE); - int byte_no; - - /* NOTE: - reading a 0 means this channel was high - writine a 0 sets the channel high - reading a 1 means this channel was low - writing a 1 means set this channel low - - Therefore everything is always inverted. */ - - /* The insn data is a mask in data[0] and the new data - * in data[1], each channel cooresponding to a bit. */ + unsigned int val; - s->state = 0; + /* get inverted state of the channels from the port */ + val = pcmuio_read(dev, asic, 0, port); - for (byte_no = 0; byte_no < s->n_chan / CHANS_PER_PORT; ++byte_no) { - /* bit offset of port in 32-bit doubleword */ - unsigned long offset = byte_no * 8; - /* this 8-bit port's data */ - unsigned char byte = 0, - /* The write mask for this port (if any) */ - write_mask_byte = (data[0] >> offset) & 0xff, - /* The data byte for this port */ - data_byte = (data[1] >> offset) & 0xff; + /* get the true state of the channels */ + s->state = val ^ ((0x1 << s->n_chan) - 1); - byte = inb(iobase + PCMUIO_PORT_REG(port + byte_no)); + if (mask) { + s->state &= ~mask; + s->state |= (mask & bits); - if (write_mask_byte) { - byte &= ~write_mask_byte; - byte |= ~data_byte & write_mask_byte; - outb(byte, iobase + PCMUIO_PORT_REG(port + byte_no)); - } - /* save the digital input lines for this byte.. */ - s->state |= ((unsigned int)byte) << offset; + /* invert the state and update the channels */ + val = s->state ^ ((0x1 << s->n_chan) - 1); + pcmuio_write(dev, val, asic, 0, port); } - /* now return the DIO lines to data[1] - note they came inverted! */ - data[1] = ~s->state; + data[1] = s->state; return insn->n; } @@ -256,58 +247,21 @@ static int pcmuio_dio_insn_config(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { + unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec); int asic = s->index / 2; int port = (s->index % 2) ? 3 : 0; - unsigned long iobase = dev->iobase + (asic * ASIC_IOSIZE); - unsigned int chan = CR_CHAN(insn->chanspec); - int byte_no = chan / 8; - int bit_no = chan % 8; - unsigned char byte; - - /* NOTE: - writing a 0 an IO channel's bit sets the channel to INPUT - and pulls the line high as well - - writing a 1 to an IO channel's bit pulls the line low - - All channels are implicitly always in OUTPUT mode -- but when - they are high they can be considered to be in INPUT mode.. - - Thus, we only force channels low if the config request was INPUT, - otherwise we do nothing to the hardware. */ switch (data[0]) { case INSN_CONFIG_DIO_OUTPUT: - /* save to io_bits -- don't actually do anything since - all input channels are also output channels... */ - s->io_bits |= 1 << chan; + s->io_bits |= chan_mask; break; case INSN_CONFIG_DIO_INPUT: - /* write a 0 to the actual register representing the channel - to set it to 'input'. 0 means "float high". */ - byte = inb(iobase + PCMUIO_PORT_REG(port + byte_no)); - byte &= ~(1 << bit_no); - /**< set input channel to '0' */ - - /* - * write out byte - * This is the only time we actually affect the hardware - * as all channels are implicitly output -- but input - * channels are set to float-high. - */ - outb(byte, iobase + PCMUIO_PORT_REG(port + byte_no)); - - /* save to io_bits */ - s->io_bits &= ~(1 << chan); + s->io_bits &= ~chan_mask; + pcmuio_write(dev, s->io_bits, asic, 0, port); break; - case INSN_CONFIG_DIO_QUERY: - /* retrieve from shadow register */ - data[1] = - (s->io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT; - return insn->n; + data[1] = (s->io_bits & chan_mask) ? COMEDI_OUTPUT : COMEDI_INPUT; break; - default: return -EINVAL; break; |