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

The `insn_read` handler for the EEPROM subdevice on E-series boards
(`ni_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 number corresponds to a single EEPROM address.)
Since we do not expect the EEPROM data at a particular address to change
between readings, let's just read it once and copy the value `insn->n`
times.

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>
This commit is contained in:
Ian Abbott 2019-03-19 16:54:43 +00:00 committed by Greg Kroah-Hartman
parent 776d25ff5b
commit 018768ccc7
1 changed files with 8 additions and 2 deletions
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10
drivers/staging/comedi/drivers/ni_mio_common.c
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@ -4507,9 +4507,15 @@ static int ni_eeprom_insn_read(struct comedi_device *dev,
struct comedi_insn *insn,
unsigned int *data)
{
data[0] = ni_read_eeprom(dev, CR_CHAN(insn->chanspec));
unsigned int val;
unsigned int i;
return 1;
if (insn->n) {
val = ni_read_eeprom(dev, CR_CHAN(insn->chanspec));
for (i = 0; i < insn->n; i++)
data[i] = val;
}
return insn->n;
}
static int ni_m_series_eeprom_insn_read(struct comedi_device *dev,