[PATCH 6/6] AT91: IIO: Add support for hardware triggers for the ADC

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Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>

Cc: Patrice Vilchez <patrice.vilchez@xxxxxxxxx>
Cc: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
---
 arch/arm/mach-at91/at91sam9260_devices.c |    3 +
 arch/arm/mach-at91/board-sam9g20ek.c     |    1 +
 drivers/staging/iio/adc/Kconfig          |   11 +-
 drivers/staging/iio/adc/at91_adc.c       |  286 +++++++++++++++++++++++++++++-
 include/linux/platform_data/at91_adc.h   |    2 +
 5 files changed, 292 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mach-at91/at91sam9260_devices.c b/arch/arm/mach-at91/at91sam9260_devices.c
index 67dad94..d30c9b8 100644
--- a/arch/arm/mach-at91/at91sam9260_devices.c
+++ b/arch/arm/mach-at91/at91sam9260_devices.c
@@ -1365,6 +1365,9 @@ void __init at91_add_device_adc(struct at91_adc_data *data)
 	if (test_bit(3, &data->channels_used))
 		at91_set_A_periph(AT91_PIN_PC3, 0);
 
+	if (data->use_external)
+		at91_set_A_periph(AT91_PIN_PA22, 0);
+
 	adc_data = *data;
 	platform_device_register(&at91_adc_device);
 }
diff --git a/arch/arm/mach-at91/board-sam9g20ek.c b/arch/arm/mach-at91/board-sam9g20ek.c
index 7758f34..f18f6f2 100644
--- a/arch/arm/mach-at91/board-sam9g20ek.c
+++ b/arch/arm/mach-at91/board-sam9g20ek.c
@@ -317,6 +317,7 @@ static void __init ek_add_device_buttons(void) {}
 
 static struct at91_adc_data ek_adc_data = {
 	.channels_used = BIT(0) | BIT(1) | BIT(2) | BIT(3),
+	.use_external = true,
 	.vref = 3300,
 };
 
diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
index 93de64d..9d87c75 100644
--- a/drivers/staging/iio/adc/Kconfig
+++ b/drivers/staging/iio/adc/Kconfig
@@ -170,10 +170,13 @@ config AD7280
 	  module will be called ad7280a
 
 config AT91_ADC
-       tristate "Atmel AT91 ADC"
-       depends on SYSFS && ARCH_AT91
-       help
-         Say yes here to build support for Atmel AT91 ADC
+	tristate "Atmel AT91 ADC"
+	depends on SYSFS && ARCH_AT91
+	select IIO_BUFFER
+	select IIO_SW_RING
+	select IIO_TRIGGER
+	help
+	  Say yes here to build support for Atmel AT91 ADC.
 
 config MAX1363
 	tristate "Maxim max1363 ADC driver"
diff --git a/drivers/staging/iio/adc/at91_adc.c b/drivers/staging/iio/adc/at91_adc.c
index 9d6e351..fe31109 100644
--- a/drivers/staging/iio/adc/at91_adc.c
+++ b/drivers/staging/iio/adc/at91_adc.c
@@ -23,10 +23,28 @@
 #include "../iio.h"
 #include <linux/platform_data/at91_adc.h>
 
+#include "../buffer.h"
+#include "../ring_sw.h"
+#include "../trigger.h"
+#include "../trigger_consumer.h"
+
 #include <mach/at91_adc.h>
 #include <mach/cpu.h>
 
 /**
+ * struct at91_adc_trigger - description of triggers
+ * @name:		name of the trigger advertised to the user
+ * @value:		value to set in the ADC's mode register to enable
+			the trigger
+ * @is_external:	is the trigger relies on an external pin ?
+ */
+struct at91_adc_trigger {
+	char	*name;
+	u8	value;
+	bool	is_external;
+};
+
+/**
  * struct at91_adc_desc - description of the ADC on the board
  * @clock:		ADC clock as specified by the datasheet, in Hz.
  * @num_channels:	global number of channels available on the board (to
@@ -34,30 +52,62 @@
 			board, see the channels_used bitmask in the platform
 			data)
  * @startup_time:	startup time of the ADC in microseconds
+ * @triggers:		array of the triggers available on the board
  */
 struct at91_adc_desc {
 	u32			clock;
 	u8			num_channels;
 	u8			startup_time;
+	struct at91_adc_trigger	*triggers;
 };
 
 struct at91_adc_state {
+	u16			*buffer;
 	u32			channels_mask;
 	struct clk		*clk;
 	bool			done;
 	struct at91_adc_desc	*desc;
 	int			irq;
+	bool			irq_enabled;
 	u16			last_value;
 	struct mutex		lock;
 	void __iomem		*reg_base;
+	struct iio_trigger	**trig;
 	u32			vref_mv;
 	wait_queue_head_t	wq_data_avail;
 };
 
+static struct at91_adc_trigger at91_adc_trigger_sam9g20[] = {
+	[0] = {
+		.name = "timer-counter-0",
+		.value = AT91_ADC_TRGSEL_TC0 | AT91_ADC_TRGEN,
+		.is_external = false,
+	},
+	[1] = {
+		.name = "timer-counter-1",
+		.value = AT91_ADC_TRGSEL_TC1 | AT91_ADC_TRGEN,
+		.is_external = false,
+	},
+	[2] = {
+		.name = "timer-counter-2",
+		.value = AT91_ADC_TRGSEL_TC2 | AT91_ADC_TRGEN,
+		.is_external = false,
+	},
+	[3] = {
+		.name = "external",
+		.value = AT91_ADC_TRGSEL_EXTERNAL | AT91_ADC_TRGEN,
+		.is_external = true,
+	},
+	[4] = {
+		.name = NULL,
+	},
+};
+
 static struct at91_adc_desc at91_adc_desc_sam9g20 = {
 	.clock = 5000000,
 	.num_channels = 4,
 	.startup_time = 10,
+	.triggers = at91_adc_trigger_sam9g20,
 };
 
 static int at91_adc_select_soc(struct at91_adc_state *st)
@@ -83,6 +133,48 @@ static inline void at91_adc_reg_write(struct at91_adc_state *st,
 	writel_relaxed(val, st->reg_base + reg);
 }
 
+static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *idev = pf->indio_dev;
+	struct at91_adc_state *st = iio_priv(idev);
+	struct iio_buffer *buffer = idev->buffer;
+	int len = 0;
+
+	if (!bitmap_empty(idev->active_scan_mask, idev->masklength)) {
+		int i, j;
+		for (i = 0, j = 0;
+		     i < bitmap_weight(idev->active_scan_mask,
+				       idev->masklength);
+		     i++) {
+			j = find_next_bit(buffer->scan_mask,
+					  idev->masklength,
+					  j);
+			st->buffer[i] = at91_adc_reg_read(st, AT91_ADC_CHR(j));
+			j++;
+			len += 2;
+		}
+	}
+
+	if (buffer->scan_timestamp) {
+		s64 *timestamp = (s64 *)((u8 *)st->buffer + ALIGN(len,
+								  sizeof(s64)));
+		*timestamp = pf->timestamp;
+	}
+
+	buffer_store_to(buffer, (u8 *)st->buffer, pf->timestamp);
+
+	iio_trigger_notify_done(idev->trig);
+	st->irq_enabled = true;
+
+	/* Needed to ACK the DRDY interruption */
+	at91_adc_reg_read(st, AT91_ADC_LCDR);
+
+	enable_irq(st->irq);
+
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
 {
 	struct iio_dev *idev = private;
@@ -92,13 +184,16 @@ static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
 	if (!(status & AT91_ADC_DRDY))
 		return IRQ_HANDLED;
 
-	if (status & st->channels_mask) {
-		st->done = true;
+	if (iio_buffer_enabled(idev)) {
+		disable_irq_nosync(irq);
+		st->irq_enabled = false;
+		iio_trigger_poll(idev->trig, iio_get_time_ns());
+	} else {
 		st->last_value = at91_adc_reg_read(st, AT91_ADC_LCDR);
+		st->done = true;
+		wake_up_interruptible(&st->wq_data_avail);
 	}
 
-	wake_up_interruptible(&st->wq_data_avail);
-
 	return IRQ_HANDLED;
 }
 
@@ -110,8 +205,9 @@ static int at91_adc_channel_init(struct iio_dev *idev,
 	int bit, idx = 0;
 
 	idev->num_channels = bitmap_weight(&pdata->channels_used,
-					   st->desc->num_channels);
-	chan_array = kcalloc(idev->num_channels, sizeof(struct iio_chan_spec),
+					   st->desc->num_channels) + 1;
+	chan_array = kcalloc(idev->num_channels + 1,
+			     sizeof(struct iio_chan_spec),
 			     GFP_KERNEL);
 
 	if (chan_array == NULL)
@@ -122,6 +218,7 @@ static int at91_adc_channel_init(struct iio_dev *idev,
 		chan->type = IIO_VOLTAGE;
 		chan->indexed = 1;
 		chan->channel = bit;
+		chan->scan_index = idx;
 		chan->scan_type.sign = 'u';
 		chan->scan_type.realbits = 10;
 		chan->scan_type.storagebits = 16;
@@ -129,6 +226,13 @@ static int at91_adc_channel_init(struct iio_dev *idev,
 		idx++;
 	}
 
+	(chan_array + idx)->type = IIO_TIMESTAMP;
+	(chan_array + idx)->channel = -1;
+	(chan_array + idx)->scan_index = idx;
+	(chan_array + idx)->scan_type.sign = 's';
+	(chan_array + idx)->scan_type.realbits = 64;
+	(chan_array + idx)->scan_type.storagebits = 64;
+
 	idev->channels = chan_array;
 	return idev->num_channels;
 }
@@ -138,6 +242,152 @@ static void at91_adc_channel_remove(struct iio_dev *idev)
 	kfree(idev->channels);
 }
 
+static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *idev = trig->private_data;
+	struct at91_adc_state *st = iio_priv(idev);
+	struct iio_buffer *buffer = idev->buffer;
+	u32 status = at91_adc_reg_read(st, AT91_ADC_MR);
+	u8 bit;
+
+	if (state) {
+		size_t datasize = buffer_get_bytes_per_datum(buffer);
+		int i;
+
+		st->buffer = kmalloc(datasize, GFP_KERNEL);
+		if (st->buffer == NULL)
+			return -ENOMEM;
+
+		for (i = 0; (st->desc->triggers + i) != NULL; i++) {
+			char *name = kasprintf(GFP_KERNEL,
+					       "%s-dev%d-%s",
+					       idev->name,
+					       idev->id,
+					       st->desc->triggers[i].name);
+			if (name == NULL)
+				return -ENOMEM;
+
+			if (strcmp(idev->trig->name, name) == 0) {
+				status |= st->desc->triggers[i].value;
+				kfree(name);
+				break;
+			}
+
+			kfree(name);
+		}
+
+		if ((st->desc->triggers + i) == NULL)
+			return -EINVAL;
+
+		at91_adc_reg_write(st, AT91_ADC_MR, status);
+
+		for_each_set_bit(bit, buffer->scan_mask,
+				 st->desc->num_channels) {
+			struct iio_chan_spec const *chan = idev->channels + bit;
+			at91_adc_reg_write(st, AT91_ADC_CHER,
+					   AT91_ADC_CH(chan->channel));
+		}
+
+		at91_adc_reg_write(st, AT91_ADC_IER, AT91_ADC_DRDY);
+
+	} else {
+		at91_adc_reg_write(st, AT91_ADC_IDR, AT91_ADC_DRDY);
+		at91_adc_reg_write(st, AT91_ADC_MR,
+				   status & ~AT91_ADC_TRGEN);
+
+		for_each_set_bit(bit, buffer->scan_mask,
+				 st->desc->num_channels) {
+			at91_adc_reg_write(st, AT91_ADC_CHDR,
+					   AT91_ADC_CH(bit));
+		}
+		kfree(st->buffer);
+	}
+
+	return 0;
+}
+
+static const struct iio_trigger_ops at91_adc_trigger_ops = {
+	.owner = THIS_MODULE,
+	.set_trigger_state = &at91_adc_configure_trigger,
+};
+
+
+static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev,
+						     struct at91_adc_trigger *trigger)
+{
+	struct iio_trigger *trig = iio_allocate_trigger("%s-dev%d-%s",
+							idev->name,
+							idev->id,
+							trigger->name);
+	int ret;
+
+	if (trig == NULL)
+		return NULL;
+
+	trig->dev.parent = idev->dev.parent;
+	trig->owner = THIS_MODULE;
+	trig->private_data = idev;
+	trig->ops = &at91_adc_trigger_ops;
+
+	ret = iio_trigger_register(trig);
+	if (ret < 0)
+		return NULL;
+
+	return trig;
+}
+
+static int at91_adc_trigger_init(struct iio_dev *idev,
+				 struct at91_adc_data *pdata)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+	int i, ret;
+
+	st->trig = kcalloc(sizeof(st->desc->triggers),
+			   sizeof(struct iio_trigger *),
+			   GFP_KERNEL);
+
+	if (st->trig == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	for (i = 0; st->desc->triggers[i].name != NULL; i++) {
+		if (st->desc->triggers[i].is_external && !(pdata->use_external))
+			continue;
+
+		st->trig[i] = at91_adc_allocate_trigger(idev,
+							st->desc->triggers + i);
+		if (st->trig[i] == NULL) {
+			ret = -ENOMEM;
+			goto error_trigger;
+		}
+	}
+
+	return 0;
+
+error_trigger:
+	for (; i >= 0; i--) {
+		iio_trigger_unregister(st->trig[i]);
+		iio_free_trigger(st->trig[i]);
+	}
+	kfree(st->trig);
+error_ret:
+	return ret;
+}
+
+static void at91_adc_trigger_remove(struct iio_dev *idev)
+{
+	struct at91_adc_state *st = iio_priv(idev);
+	int i;
+
+	for (i = 0; st->desc->triggers[i].name != NULL; i++) {
+		iio_trigger_unregister(st->trig[i]);
+		iio_free_trigger(st->trig[i]);
+	}
+
+	kfree(st->trig);
+}
+
 static int at91_adc_read_raw(struct iio_dev *idev,
 			     struct iio_chan_spec const *chan,
 			     int *val, int *val2, long mask)
@@ -321,14 +571,34 @@ static int __devinit at91_adc_probe(struct platform_device *pdev)
 	st->vref_mv = pdata->vref;
 	st->channels_mask = pdata->channels_used;
 
+	ret = iio_sw_rb_simple_setup(idev,
+				     &iio_pollfunc_store_time,
+				     &at91_adc_trigger_handler);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
+		goto error_free_channels;
+	}
+
+	idev->buffer->scan_timestamp = true;
+
+	ret = at91_adc_trigger_init(idev, pdata);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
+		goto error_unregister_buffer;
+	}
+
 	ret = iio_device_register(idev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Couldn't register the device.\n");
-		goto error_free_channels;
+		goto error_remove_triggers;
 	}
 
 	return 0;
 
+error_remove_triggers:
+	at91_adc_trigger_remove(idev);
+error_unregister_buffer:
+	iio_sw_rb_simple_cleanup(idev);
 error_free_channels:
 	at91_adc_channel_remove(idev);
 error_free_clk:
@@ -353,6 +623,8 @@ static int __devexit at91_adc_remove(struct platform_device *pdev)
 	struct at91_adc_state *st = iio_priv(idev);
 
 	iio_device_unregister(idev);
+	at91_adc_trigger_remove(idev);
+	iio_sw_rb_simple_cleanup(idev);
 	at91_adc_channel_remove(idev);
 	clk_disable(st->clk);
 	clk_put(st->clk);
diff --git a/include/linux/platform_data/at91_adc.h b/include/linux/platform_data/at91_adc.h
index ab43de8..b1d3a6d 100644
--- a/include/linux/platform_data/at91_adc.h
+++ b/include/linux/platform_data/at91_adc.h
@@ -18,10 +18,12 @@
 /**
  * struct at91_adc_data - platform data for ADC driver
  * @channels_use:	channels in use on the board as a bitmask
+ * @use_external:	does the board has external triggers availables
  * @vref:		Reference voltage for the ADC in millvolts
  */
 struct at91_adc_data {
 	u32	channels_used;
+	bool	use_external;
 	u16	vref;
 };
 
-- 
1.7.4.1

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