Merge branch 'at91-5.4-trunk/base_adc' into linux-5.4-at91

Author: cristibirsan

drivers/iio/adc/at91-sama5d2_adc.c

@@ -8,6 +8,7 @@
 
 #include <linux/bitops.h>
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/dma-mapping.h>
 #include <linux/dmaengine.h>
 #include <linux/interrupt.h>
@@ -100,6 +101,8 @@
 #define AT91_SAMA5D2_IER_YRDY   BIT(21)
 /* Interrupt Enable Register - TS pressure measurement ready */
 #define AT91_SAMA5D2_IER_PRDY   BIT(22)
+/* Interrupt Enable Register - Data ready */
+#define AT91_SAMA5D2_IER_DRDY   BIT(24)
 /* Interrupt Enable Register - general overrun error */
 #define AT91_SAMA5D2_IER_GOVRE BIT(25)
 /* Interrupt Enable Register - Pen detect */
@@ -486,6 +489,21 @@ static inline int at91_adc_of_xlate(struct iio_dev *indio_dev,
 	return at91_adc_chan_xlate(indio_dev, iiospec->args[0]);
 }
 
+static unsigned int at91_adc_active_scan_mask_to_reg(struct iio_dev *indio_dev)
+{
+	u32 mask = 0;
+	u8 bit;
+
+	for_each_set_bit(bit, indio_dev->active_scan_mask,
+			 indio_dev->num_channels) {
+		struct iio_chan_spec const *chan =
+			 at91_adc_chan_get(indio_dev, bit);
+		mask |= BIT(chan->channel);
+	}
+
+	return mask & GENMASK(11, 0);
+}
+
 static void at91_adc_config_emr(struct at91_adc_state *st)
 {
 	/* configure the extended mode register */
@@ -710,7 +728,6 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
 	struct iio_dev *indio = iio_trigger_get_drvdata(trig);
 	struct at91_adc_state *st = iio_priv(indio);
 	u32 status = at91_adc_readl(st, AT91_SAMA5D2_TRGR);
-	u8 bit;
 
 	/* clear TRGMOD */
 	status &= ~AT91_SAMA5D2_TRGR_TRGMOD_MASK;
@@ -721,50 +738,6 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
 	/* set/unset hw trigger */
 	at91_adc_writel(st, AT91_SAMA5D2_TRGR, status);
 
-	for_each_set_bit(bit, indio->active_scan_mask, indio->num_channels) {
-		struct iio_chan_spec const *chan = at91_adc_chan_get(indio, bit);
-		u32 cor;
-
-		if (!chan)
-			continue;
-		/* these channel types cannot be handled by this trigger */
-		if (chan->type == IIO_POSITIONRELATIVE ||
-		    chan->type == IIO_PRESSURE)
-			continue;
-
-		if (state) {
-			cor = at91_adc_readl(st, AT91_SAMA5D2_COR);
-
-			if (chan->differential)
-				cor |= (BIT(chan->channel) |
-					BIT(chan->channel2)) <<
-					AT91_SAMA5D2_COR_DIFF_OFFSET;
-			else
-				cor &= ~(BIT(chan->channel) <<
-				       AT91_SAMA5D2_COR_DIFF_OFFSET);
-
-			at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
-		}
-
-		if (state) {
-			at91_adc_writel(st, AT91_SAMA5D2_CHER,
-					BIT(chan->channel));
-			/* enable irq only if not using DMA */
-			if (!st->dma_st.dma_chan) {
-				at91_adc_writel(st, AT91_SAMA5D2_IER,
-						BIT(chan->channel));
-			}
-		} else {
-			/* disable irq only if not using DMA */
-			if (!st->dma_st.dma_chan) {
-				at91_adc_writel(st, AT91_SAMA5D2_IDR,
-						BIT(chan->channel));
-			}
-			at91_adc_writel(st, AT91_SAMA5D2_CHDR,
-					BIT(chan->channel));
-		}
-	}
-
 	return 0;
 }
 
@@ -781,6 +754,7 @@ static int at91_adc_reenable_trigger(struct iio_trigger *trig)
 
 	/* Needed to ACK the DRDY interruption */
 	at91_adc_readl(st, AT91_SAMA5D2_LCDR);
+
 	return 0;
 }
 
@@ -888,18 +862,37 @@ static int at91_adc_dma_start(struct iio_dev *indio_dev)
 	return 0;
 }
 
+static bool at91_adc_buffer_check_use_irq(struct iio_dev *indio,
+					  struct at91_adc_state *st)
+{
+	/* if using DMA, we do not use our own IRQ (we use DMA-controller) */
+	if (st->dma_st.dma_chan)
+		return false;
+	/* if the trigger is not ours, then it has its own IRQ */
+	if (iio_trigger_validate_own_device(indio->trig, indio))
+		return false;
+	return true;
+}
+
+static bool at91_adc_current_chan_is_touch(struct iio_dev *indio_dev)
+{
+	struct at91_adc_state *st = iio_priv(indio_dev);
+
+	return !!bitmap_subset(indio_dev->active_scan_mask,
+			       &st->touch_st.channels_bitmask,
+			       AT91_SAMA5D2_MAX_CHAN_IDX + 1);
+}
+
 static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
 {
 	int ret;
+	u8 bit;
 	struct at91_adc_state *st = iio_priv(indio_dev);
 
 	/* check if we are enabling triggered buffer or the touchscreen */
-	if (bitmap_subset(indio_dev->active_scan_mask,
-			  &st->touch_st.channels_bitmask,
-			  AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
-		/* touchscreen enabling */
+	if (at91_adc_current_chan_is_touch(indio_dev))
 		return at91_adc_configure_touch(st, true);
-	}
+
 	/* if we are not in triggered mode, we cannot enable the buffer. */
 	if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
 		return -EINVAL;
@@ -911,6 +904,36 @@ static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
 		return ret;
 	}
 
+	for_each_set_bit(bit, indio_dev->active_scan_mask,
+			 indio_dev->num_channels) {
+		struct iio_chan_spec const *chan =
+					at91_adc_chan_get(indio_dev, bit);
+		u32 cor;
+
+		if (!chan)
+			continue;
+		/* these channel types cannot be handled by this trigger */
+		if (chan->type == IIO_POSITIONRELATIVE ||
+		    chan->type == IIO_PRESSURE)
+			continue;
+
+		cor = at91_adc_readl(st, AT91_SAMA5D2_COR);
+
+		if (chan->differential)
+			cor |= (BIT(chan->channel) | BIT(chan->channel2)) <<
+				AT91_SAMA5D2_COR_DIFF_OFFSET;
+		else
+			cor &= ~(BIT(chan->channel) <<
+			       AT91_SAMA5D2_COR_DIFF_OFFSET);
+
+		at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
+
+		at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
+	}
+
+	if (at91_adc_buffer_check_use_irq(indio_dev, st))
+		at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_DRDY);
+
 	return iio_triggered_buffer_postenable(indio_dev);
 }
 
@@ -921,31 +944,18 @@ static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
 	u8 bit;
 
 	/* check if we are disabling triggered buffer or the touchscreen */
-	if (bitmap_subset(indio_dev->active_scan_mask,
-			  &st->touch_st.channels_bitmask,
-			  AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
-		/* touchscreen disable */
+	if (at91_adc_current_chan_is_touch(indio_dev))
 		return at91_adc_configure_touch(st, false);
-	}
+
 	/* if we are not in triggered mode, nothing to do here */
 	if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
 		return -EINVAL;
 
-	/* continue with the triggered buffer */
-	ret = iio_triggered_buffer_predisable(indio_dev);
-	if (ret < 0)
-		dev_err(&indio_dev->dev, "buffer predisable failed\n");
-
-	if (!st->dma_st.dma_chan)
-		return ret;
-
-	/* if we are using DMA we must clear registers and end DMA */
-	dmaengine_terminate_sync(st->dma_st.dma_chan);
-
 	/*
-	 * For each enabled channel we must read the last converted value
+	 * For each enable channel we must disable it in hardware.
+	 * In the case of DMA, we must read the last converted value
 	 * to clear EOC status and not get a possible interrupt later.
-	 * This value is being read by DMA from LCDR anyway
+	 * This value is being read by DMA from LCDR anyway, so it's not lost.
 	 */
 	for_each_set_bit(bit, indio_dev->active_scan_mask,
 			 indio_dev->num_channels) {
@@ -958,12 +968,28 @@ static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
 		if (chan->type == IIO_POSITIONRELATIVE ||
 		    chan->type == IIO_PRESSURE)
 			continue;
+
+		at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
+
 		if (st->dma_st.dma_chan)
 			at91_adc_readl(st, chan->address);
 	}
 
+	if (at91_adc_buffer_check_use_irq(indio_dev, st))
+		at91_adc_writel(st, AT91_SAMA5D2_IDR, AT91_SAMA5D2_IER_DRDY);
+
 	/* read overflow register to clear possible overflow status */
 	at91_adc_readl(st, AT91_SAMA5D2_OVER);
+
+	/* continue with the triggered buffer */
+	ret = iio_triggered_buffer_predisable(indio_dev);
+	if (ret < 0)
+		dev_err(&indio_dev->dev, "buffer predisable failed\n");
+
+	/* if we are using DMA we must clear registers and end DMA */
+	if (st->dma_st.dma_chan)
+		dmaengine_terminate_sync(st->dma_st.dma_chan);
+
 	return ret;
 }
 
@@ -1015,6 +1041,22 @@ static void at91_adc_trigger_handler_nodma(struct iio_dev *indio_dev,
 	int i = 0;
 	int val;
 	u8 bit;
+	u32 mask = at91_adc_active_scan_mask_to_reg(indio_dev);
+	unsigned int timeout = 50;
+
+	/*
+	 * Check if the conversion is ready. If not, wait a little bit, and
+	 * in case of timeout exit with an error.
+	 */
+	while ((at91_adc_readl(st, AT91_SAMA5D2_ISR) & mask) != mask &&
+	       timeout) {
+		usleep_range(50, 100);
+		timeout--;
+	}
+
+	/* Cannot read data, not ready. Continue without reporting data */
+	if (!timeout)
+		return;
 
 	for_each_set_bit(bit, indio_dev->active_scan_mask,
 			 indio_dev->num_channels) {
@@ -1102,6 +1144,13 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct at91_adc_state *st = iio_priv(indio_dev);
 
+	/*
+	 * If it's not our trigger, start a conversion now, as we are
+	 * actually polling the trigger now.
+	 */
+	if (iio_trigger_validate_own_device(indio_dev->trig, indio_dev))
+		at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
+
 	if (st->dma_st.dma_chan)
 		at91_adc_trigger_handler_dma(indio_dev);
 	else
@@ -1114,20 +1163,9 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
 
 static int at91_adc_buffer_init(struct iio_dev *indio)
 {
-	struct at91_adc_state *st = iio_priv(indio);
-
-	if (st->selected_trig->hw_trig) {
-		return devm_iio_triggered_buffer_setup(&indio->dev, indio,
-			&iio_pollfunc_store_time,
-			&at91_adc_trigger_handler, &at91_buffer_setup_ops);
-	}
-	/*
-	 * we need to prepare the buffer ops in case we will get
-	 * another buffer attached (like a callback buffer for the touchscreen)
-	 */
-	indio->setup_ops = &at91_buffer_setup_ops;
-
-	return 0;
+	return devm_iio_triggered_buffer_setup(&indio->dev, indio,
+		&iio_pollfunc_store_time,
+		&at91_adc_trigger_handler, &at91_buffer_setup_ops);
 }
 
 static unsigned at91_adc_startup_time(unsigned startup_time_min,
@@ -1281,7 +1319,8 @@ static irqreturn_t at91_adc_interrupt(int irq, void *private)
 		status = at91_adc_readl(st, AT91_SAMA5D2_XPOSR);
 		status = at91_adc_readl(st, AT91_SAMA5D2_YPOSR);
 		status = at91_adc_readl(st, AT91_SAMA5D2_PRESSR);
-	} else if (iio_buffer_enabled(indio) && !st->dma_st.dma_chan) {
+	} else if (iio_buffer_enabled(indio) &&
+		   (status & AT91_SAMA5D2_IER_DRDY)) {
 		/* triggered buffer without DMA */
 		disable_irq_nosync(irq);
 		iio_trigger_poll(indio->trig);
@@ -1901,14 +1940,10 @@ static __maybe_unused int at91_adc_resume(struct device *dev)
 		return 0;
 
 	/* check if we are enabling triggered buffer or the touchscreen */
-	if (bitmap_subset(indio_dev->active_scan_mask,
-			  &st->touch_st.channels_bitmask,
-			  AT91_SAMA5D2_MAX_CHAN_IDX + 1)) {
-		/* touchscreen enabling */
+	if (at91_adc_current_chan_is_touch(indio_dev))
 		return at91_adc_configure_touch(st, true);
-	} else {
+	else
 		return at91_adc_configure_trigger(st->trig, true);
-	}
 
 	/* not needed but more explicit */
 	return 0;