staging: comedi: pcmmio: return error if ai conversion times out

Rename adc_wait_ready() so it has namespace associated with the
driver.

Fix the function so it returns an errno if the conversion times
out. Propogate this errno if it happens.

Define the analog input status register to remove the magic numbers.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/pcmmio.c

@@ -90,6 +90,15 @@ Configuration Options:
 #define PCMMIO_AI_CMD_ODD_CHAN		(1 << 6)
 #define PCMMIO_AI_CMD_CHAN_SEL(x)	(((x) & 0x3) << 4)
 #define PCMMIO_AI_CMD_RANGE(x)		(((x) & 0x3) << 2)
+#define PCMMIO_AI_STATUS_REG		0x03
+#define PCMMIO_AI_STATUS_DATA_READY	(1 << 7)
+#define PCMMIO_AI_STATUS_DATA_DMA_PEND	(1 << 6)
+#define PCMMIO_AI_STATUS_CMD_DMA_PEND	(1 << 5)
+#define PCMMIO_AI_STATUS_IRQ_PEND	(1 << 4)
+#define PCMMIO_AI_STATUS_DATA_DRQ_ENA	(1 << 2)
+#define PCMMIO_AI_STATUS_REG_SEL	(1 << 3)
+#define PCMMIO_AI_STATUS_CMD_DRQ_ENA	(1 << 1)
+#define PCMMIO_AI_STATUS_IRQ_ENA	(1 << 0)
 
 /* This stuff is all from pcmuio.c -- it refers to the DIO subdevices only */
 #define CHANS_PER_PORT   8
@@ -763,13 +772,16 @@ static int pcmmio_cmdtest(struct comedi_device *dev,
 	return 0;
 }
 
-static int adc_wait_ready(unsigned long iobase)
+static int pcmmio_ai_wait_for_eoc(unsigned long iobase, unsigned int timeout)
 {
-	unsigned long retry = 100000;
-	while (retry--)
-		if (inb(iobase + 3) & 0x80)
+	unsigned char status;
+
+	while (timeout--) {
+		status = inb(iobase + PCMMIO_AI_STATUS_REG);
+		if (status & PCMMIO_AI_STATUS_DATA_READY)
 			return 0;
-	return 1;
+	}
+	return -ETIME;
 }
 
 static int pcmmio_ai_insn_read(struct comedi_device *dev,
@@ -783,6 +795,7 @@ static int pcmmio_ai_insn_read(struct comedi_device *dev,
 	unsigned int aref = CR_AREF(insn->chanspec);
 	unsigned char cmd = 0;
 	unsigned int val;
+	int ret;
 	int i;
 
 	/*
@@ -813,14 +826,18 @@ static int pcmmio_ai_insn_read(struct comedi_device *dev,
 	cmd |= PCMMIO_AI_CMD_RANGE(range);
 
 	outb(cmd, iobase + PCMMIO_AI_CMD_REG);
-	adc_wait_ready(iobase);
+	ret = pcmmio_ai_wait_for_eoc(iobase, 100000);
+	if (ret)
+		return ret;
 
 	val = inb(iobase + PCMMIO_AI_LSB_REG);
 	val |= inb(iobase + PCMMIO_AI_MSB_REG) << 8;
 
 	for (i = 0; i < insn->n; i++) {
 		outb(cmd, iobase + PCMMIO_AI_CMD_REG);
-		adc_wait_ready(iobase);
+		ret = pcmmio_ai_wait_for_eoc(iobase, 100000);
+		if (ret)
+			return ret;
 
 		val = inb(iobase + PCMMIO_AI_LSB_REG);
 		val |= inb(iobase + PCMMIO_AI_MSB_REG) << 8;