Re: [PATCH 3/4] input: ti_tsc: Enable shared IRQ for TSC and add overrun, underflow checks

On Fri, Aug 16, 2013 at 11:14:09AM +0200, Sebastian Andrzej Siewior wrote:

* Zubair Lutfullah | 2013-08-13 17:48:18 [+0100]:

quoted

+	if ((status & IRQENB_FIFO0OVRRUN) ||
+			(status & IRQENB_FIFO0UNDRFLW)) {
+
+		config = titsc_readl(ts_dev, REG_CTRL);
+		config &= ~(CNTRLREG_TSCSSENB);
+		titsc_writel(ts_dev, REG_CTRL, config);
+
+		if (status & IRQENB_FIFO0UNDRFLW) {
+			titsc_writel(ts_dev, REG_IRQSTATUS,
+				(status | IRQENB_FIFO0UNDRFLW));
+			irqclr |= IRQENB_FIFO0UNDRFLW;
+		} else {
+			titsc_writel(ts_dev, REG_IRQSTATUS,
+				(status | IRQENB_FIFO0OVRRUN));
+			irqclr |= IRQENB_FIFO0OVRRUN;
+		}

You don't do anything on overflow / underflow. Is this due to the fact
once enabled for FIFO1 it also triggers for FIFO0?

The TSCADC module doesn't recover from these interrupts.

quoted

+		titsc_writel(ts_dev, REG_CTRL,
+			(config | CNTRLREG_TSCSSENB));

The fix is to re-enable the module after disabling 
and clearing the interrupts.

That is what the handler is doing.

quoted

+	} else if (status & IRQENB_FIFO0THRES) {
		titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);

		if (ts_dev->pen_down && z1 != 0 && z2 != 0) {

@@ -317,9 +342,11 @@ static irqreturn_t titsc_irq(int irq, void *dev)

	}

	if (irqclr) {
-		titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
+		titsc_writel(ts_dev, REG_IRQSTATUS, (status | irqclr));

Shouldn't FIFO1UNDRFLW & OVRRUN be handled by the adc driver? Why do you
or the unhandled bits as well here?

FIFO1 is only used by TSC. ADC doesn't touch it.

quoted

		am335x_tsc_se_set(ts_dev->mfd_tscadc, ts_dev->step_mask);
-		return IRQ_HANDLED;
+		status = titsc_readl(ts_dev, REG_IRQSTATUS);
+		if (status == false)
+			return IRQ_HANDLED;

And why this? If you something you handled it, if you didn't you return
NONE. Why does it depend on REG_IRQSTATUS?

These quirks are to handle the situation where both IRQs happen
simultaneously. Which can occur when someone is using the TSC
while continuously sampling using the ADC.

REG_IRQSTATUS has flags for FIFO0 used by ADC as well.

If there are still those IRQs to handle, then IRQ_NONE is returned.
Otherwise, all IRQ flags are clear so IRQ_HANDLED is returned.

Thanks
Zubair