From 9a1f72233f4d79165b9b3321b792549145291547 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Wed, 11 Jul 2012 13:28:19 +0100 Subject: [PATCH] staging: comedi: rtd520: add a few comments H Hartley Sweeten's recent series of patches to clean up the rtd520 driver made some of the register accesses harder to understand. Add a few comments to provide some clues to the reader. Signed-off-by: Ian Abbott Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/rtd520.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/staging/comedi/drivers/rtd520.c b/drivers/staging/comedi/drivers/rtd520.c index 5a2953e9d900..9998d6b25d2e 100644 --- a/drivers/staging/comedi/drivers/rtd520.c +++ b/drivers/staging/comedi/drivers/rtd520.c @@ -494,6 +494,7 @@ static int rtd520_probe_fifo_depth(struct comedi_device *dev) writel(0, devpriv->las0 + LAS0_ADC_FIFO_CLEAR); rtd_load_channelgain_list(dev, 1, &chanspec); + /* ADC conversion trigger source: SOFTWARE */ writel(0, devpriv->las0 + LAS0_ADC_CONVERSION); /* convert samples */ for (i = 0; i < limit; ++i) { @@ -544,7 +545,7 @@ static int rtd_ai_rinsn(struct comedi_device *dev, /* write channel to multiplexer and clear channel gain table */ rtd_load_channelgain_list(dev, 1, &insn->chanspec); - /* set conversion source */ + /* ADC conversion trigger source: SOFTWARE */ writel(0, devpriv->las0 + LAS0_ADC_CONVERSION); /* convert n samples */ @@ -908,8 +909,9 @@ abortTransfer: /* fall into transferDone */ transferDone: + /* pacer stop source: SOFTWARE */ writel(0, devpriv->las0 + LAS0_PACER_STOP); - writel(0, devpriv->las0 + LAS0_PACER); + writel(0, devpriv->las0 + LAS0_PACER); /* stop pacer */ writel(0, devpriv->las0 + LAS0_ADC_CONVERSION); devpriv->intMask = 0; writew(devpriv->intMask, devpriv->las0 + LAS0_IT); @@ -1180,8 +1182,9 @@ static int rtd_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) int timer; /* stop anything currently running */ + /* pacer stop source: SOFTWARE */ writel(0, devpriv->las0 + LAS0_PACER_STOP); - writel(0, devpriv->las0 + LAS0_PACER); + writel(0, devpriv->las0 + LAS0_PACER); /* stop pacer */ writel(0, devpriv->las0 + LAS0_ADC_CONVERSION); devpriv->intMask = 0; writew(devpriv->intMask, devpriv->las0 + LAS0_IT); @@ -1215,12 +1218,17 @@ static int rtd_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) /* setup the common case and override if needed */ if (cmd->chanlist_len > 1) { /*DPRINTK ("rtd520: Multi channel setup\n"); */ + /* pacer start source: SOFTWARE */ writel(0, devpriv->las0 + LAS0_PACER_START); + /* burst trigger source: PACER */ writel(1, devpriv->las0 + LAS0_BURST_START); + /* ADC conversion trigger source: BURST */ writel(2, devpriv->las0 + LAS0_ADC_CONVERSION); } else { /* single channel */ /*DPRINTK ("rtd520: single channel setup\n"); */ + /* pacer start source: SOFTWARE */ writel(0, devpriv->las0 + LAS0_PACER_START); + /* ADC conversion trigger source: PACER */ writel(1, devpriv->las0 + LAS0_ADC_CONVERSION); } writel((devpriv->fifoLen / 2 - 1) & 0xffff, devpriv->las0 + LAS0_ACNT); @@ -1269,7 +1277,9 @@ static int rtd_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) devpriv->transCount = 0; devpriv->flags &= ~SEND_EOS; } + /* pacer clock source: INTERNAL 8MHz */ writel(1, devpriv->las0 + LAS0_PACER_SELECT); + /* just interrupt, don't stop */ writel(1, devpriv->las0 + LAS0_ACNT_STOP_ENABLE); /* BUG??? these look like enumerated values, but they are bit fields */ @@ -1305,6 +1315,7 @@ static int rtd_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) break; case TRIG_EXT: + /* pacer start source: EXTERNAL */ writel(1, devpriv->las0 + LAS0_PACER_START); break; @@ -1327,6 +1338,7 @@ static int rtd_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) break; case TRIG_EXT: /* external */ + /* burst trigger source: EXTERNAL */ writel(2, devpriv->las0 + LAS0_BURST_START); break; @@ -1378,7 +1390,7 @@ static int rtd_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) /* BUG: start_src is ASSUMED to be TRIG_NOW */ /* BUG? it seems like things are running before the "start" */ - readl(devpriv->las0 + LAS0_PACER); + readl(devpriv->las0 + LAS0_PACER); /* start pacer */ return 0; } @@ -1391,8 +1403,9 @@ static int rtd_ai_cancel(struct comedi_device *dev, struct comedi_subdevice *s) u32 overrun; u16 status; + /* pacer stop source: SOFTWARE */ writel(0, devpriv->las0 + LAS0_PACER_STOP); - writel(0, devpriv->las0 + LAS0_PACER); + writel(0, devpriv->las0 + LAS0_PACER); /* stop pacer */ writel(0, devpriv->las0 + LAS0_ADC_CONVERSION); devpriv->intMask = 0; writew(devpriv->intMask, devpriv->las0 + LAS0_IT); -- 2.34.1