On Wednesday, April 24, 2013 2:09 AM, Ian Abbott wrote:
> On 2013-04-23 20:58, H Hartley Sweeten wrote:
>> The bits needed to set the analog input gain can be simply calculated
>> based on the 'range'.
>>
>> The LabPC versions of the board do not have the '0x10' gain that the
>> LabPC+ board supports. By incrementing the range appropriately the
>> correct gain bits can still be calculated.
>>
>> This allows removing the two gain tables, as well as the export, along
>> with the 'ai_range_code' data in the boardinfo.
>>
>> Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
>> Cc: Ian Abbott <abbbotti@xxxxxxxxx>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/staging/comedi/drivers/ni_labpc.c | 30 +++++++++++++--------------
>> drivers/staging/comedi/drivers/ni_labpc.h | 3 ---
>> drivers/staging/comedi/drivers/ni_labpc_cs.c | 1 -
>> drivers/staging/comedi/drivers/ni_labpc_pci.c | 1 -
>> 4 files changed, 14 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c
>> index 5ed9a6f..773368d 100644
>> --- a/drivers/staging/comedi/drivers/ni_labpc.c
>> +++ b/drivers/staging/comedi/drivers/ni_labpc.c
>> @@ -88,7 +88,7 @@
>> #define CMD1_REG 0x00 /* W: Command 1 reg */
>> #define CMD1_MA(x) (((x) & 0x7) << 0)
>> #define CMD1_TWOSCMP (1 << 3)
>> -#define CMD1_GAIN_MASK (7 << 4)
>> +#define CMD1_GAIN(x) (((x) & 0x7) << 4)
>> #define CMD1_SCANEN (1 << 7)
>> #define CMD2_REG 0x01 /* W: Command 2 reg */
>> #define CMD2_PRETRIG (1 << 0)
>> @@ -153,11 +153,6 @@ enum scan_mode {
>> MODE_MULT_CHAN_DOWN,
>> };
>>
>> -static const int labpc_plus_ai_gain_bits[] = {
>> - 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
>> - 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
>> -};
>> -
>> static const struct comedi_lrange range_labpc_plus_ai = {
>> 16, {
>> BIP_RANGE(5),
>> @@ -179,12 +174,6 @@ static const struct comedi_lrange range_labpc_plus_ai = {
>> }
>> };
>>
>> -const int labpc_1200_ai_gain_bits[] = {
>> - 0x00, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
>> - 0x00, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
>> -};
>> -EXPORT_SYMBOL_GPL(labpc_1200_ai_gain_bits);
>> -
>> static const struct comedi_lrange range_labpc_1200_ai = {
>> 14, {
>> BIP_RANGE(5),
>> @@ -237,20 +226,17 @@ static inline void labpc_writeb(unsigned int byte, unsigned long address)
>> static const struct labpc_boardinfo labpc_boards[] = {
>> {
>> .name = "lab-pc-1200",
>> - .ai_range_code = labpc_1200_ai_gain_bits,
>> .ai_speed = 10000,
>> .ai_scan_up = 1,
>> .has_ao = 1,
>> .is_labpc1200 = 1,
>> }, {
>> .name = "lab-pc-1200ai",
>> - .ai_range_code = labpc_1200_ai_gain_bits,
>> .ai_speed = 10000,
>> .ai_scan_up = 1,
>> .is_labpc1200 = 1,
>> }, {
>> .name = "lab-pc+",
>> - .ai_range_code = labpc_plus_ai_gain_bits,
>> .ai_speed = 12000,
>> .has_ao = 1,
>> },
>> @@ -321,12 +307,24 @@ static void labpc_ai_set_chan_and_gain(struct comedi_device *dev,
>> const struct labpc_boardinfo *board = comedi_board(dev);
>> struct labpc_private *devpriv = dev->private;
>>
>> + if (board->is_labpc1200) {
>> + /*
>> + * The LabPC-1200 boards do not have a gain
>> + * of '0x10'. Skip the range values that would
>> + * result in this gain.
>> + */
>> + if (range > 1)
>> + range++;
>> + if (range > 8)
>> + range++;
>
> Off-by one error. That would change the sequence 0 to 13 to the following:
>
> 0, 1, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15
>
> I think you meant:
>
> if (range > 0)
> range++;
> if (range > 8)
> range++;
>
> which maps the sequence 0 to 13 to the following:
>
> 0, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15
Ugh.. You are correct. Brain fart with that.
> You could also use:
>
> range += (range > 0) + (range > 7);
>
> which I think is easier to understand (and doesn't need the curly braces).
I like that one better. I'll update the patch.
Greg,
Do you want all four patchs again as v2 or just an update of this one?
> Probably harder to understand, and possibly not as efficient, but this
> also works:
>
> range = (((range + 6) * 8) / 7) - 6;
That one is nasty... ;-)
Thanks,
Hartley
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