From: Ian Abbott Date: Fri, 1 Feb 2013 14:51:57 +0000 (+0000) Subject: staging: comedi: ni_labpc: set up command4 register *after* command3 X-Git-Tag: v3.12-rc1~1406^2~158 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=22056e2b46246d97ff0f7c6e21a77b8daa07f02c;p=kernel%2Fkernel-generic.git staging: comedi: ni_labpc: set up command4 register *after* command3 Tuomas reported problems getting meaningful output from a Lab-PC+ in differential mode for AI cmds, but AI insn reads gave correct readings. He tracked it down to two problems, one of which is addressed by this patch. It seems that writing to the command3 register after writing to the command4 register in `labpc_ai_cmd()` messes up the differential reference bit setting in the command4 register. Set up the command4 register after the command3 register (as in `labpc_ai_rinsn()`) to avoid the problem. Thanks to Tuomas for suggesting the fix. Signed-off-by: Ian Abbott Cc: # 3.7.x, 3.8.x Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c index 9e4d2da..10bd2b3 100644 --- a/drivers/staging/comedi/drivers/ni_labpc.c +++ b/drivers/staging/comedi/drivers/ni_labpc.c @@ -1219,21 +1219,6 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) devpriv->write_byte(devpriv->command1_bits, dev->iobase + COMMAND1_REG); } - /* setup any external triggering/pacing (command4 register) */ - devpriv->command4_bits = 0; - if (cmd->convert_src != TRIG_EXT) - devpriv->command4_bits |= EXT_CONVERT_DISABLE_BIT; - /* XXX should discard first scan when using interval scanning - * since manual says it is not synced with scan clock */ - if (labpc_use_continuous_mode(cmd, mode) == 0) { - devpriv->command4_bits |= INTERVAL_SCAN_EN_BIT; - if (cmd->scan_begin_src == TRIG_EXT) - devpriv->command4_bits |= EXT_SCAN_EN_BIT; - } - /* single-ended/differential */ - if (aref == AREF_DIFF) - devpriv->command4_bits |= ADC_DIFF_BIT; - devpriv->write_byte(devpriv->command4_bits, dev->iobase + COMMAND4_REG); devpriv->write_byte(cmd->chanlist_len, dev->iobase + INTERVAL_COUNT_REG); @@ -1313,6 +1298,22 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) devpriv->command3_bits &= ~ADC_FNE_INTR_EN_BIT; devpriv->write_byte(devpriv->command3_bits, dev->iobase + COMMAND3_REG); + /* setup any external triggering/pacing (command4 register) */ + devpriv->command4_bits = 0; + if (cmd->convert_src != TRIG_EXT) + devpriv->command4_bits |= EXT_CONVERT_DISABLE_BIT; + /* XXX should discard first scan when using interval scanning + * since manual says it is not synced with scan clock */ + if (labpc_use_continuous_mode(cmd, mode) == 0) { + devpriv->command4_bits |= INTERVAL_SCAN_EN_BIT; + if (cmd->scan_begin_src == TRIG_EXT) + devpriv->command4_bits |= EXT_SCAN_EN_BIT; + } + /* single-ended/differential */ + if (aref == AREF_DIFF) + devpriv->command4_bits |= ADC_DIFF_BIT; + devpriv->write_byte(devpriv->command4_bits, dev->iobase + COMMAND4_REG); + /* startup acquisition */ /* command2 reg */