staging: comedi: ni_mio_common: use insn->n in ni_m_series_eeprom_insn_read()

The `insn_read` handler for the EEPROM subdevice on M-series boards
(`ni_m_series_eeprom_insn_read()`) currently ignores `insn->n` (the
number of samples to read) and assumes a single sample is to be read
into `data[0]`.  Fortunately, the Comedi core ensures that `data[]` has
a length of at least 16 so there is no problem with array bounds.

The usual Comedi convention for `insn_read` handlers is to read the same
channel `insn->n` times into successive elements of `data[]` so let's do
that.  (Each channel corresponds to a single EEPROM address.)  In this
case, the data value comes from a local copy of the EEPROM contents.

Also, follow the usual Comedi convention and return `insn->n` from the
handler to indicate success (although any non-negative value will do).

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
index 5b397ad2a6043bc50af1c41027fc2948eb398042..5eef1a63e3eb2d39fdd807aa75eed7344c663486 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_mio_common.c
+++ b/drivers/staging/comedi/drivers/ni_mio_common.c
@@ -4524,10 +4524,12 @@ static int ni_m_series_eeprom_insn_read(struct comedi_device *dev,
                                        unsigned int *data)
 {
        struct ni_private *devpriv = dev->private;
+       unsigned int i;
 
-       data[0] = devpriv->eeprom_buffer[CR_CHAN(insn->chanspec)];
+       for (i = 0; i < insn->n; i++)
+               data[i] = devpriv->eeprom_buffer[CR_CHAN(insn->chanspec)];
 
-       return 1;
+       return insn->n;
 }
 
 static unsigned int ni_old_get_pfi_routing(struct comedi_device *dev,