[PATCH v4] iio: adc: vf610: Add IIO buffer support for Vybrid ADC

[Sanchayan Maity]

This patch adds support for IIO buffer to the Vybrid ADC driver.
IIO triggered buffer infrastructure along with iio sysfs trigger
is used to leverage continuous sampling support provided by the
ADC block.

Signed-off-by: Sanchayan Maity <maitysanchayan@xxxxxxxxx>
---

Changes since v3:
Fix iio_buffer_setup_ops for postenable and predisable functions
to match pairwise. Before this the predisable work was being done
in postdisable.

Changes since v2:
1. Fix the wrong buffer size for statically allocated buffer
2. Drop the use of .address field from the iio_chan_spec
3. Use iio_buffer_enabled call inside the lock
4. Drop wrapper function around iio_trigered_* function calls
5. Drop Kconfig select of sysfs trigger
6. Drop Kconfig select IIO_TRIGGER as it is already selected by
IIO_TRIGGERED_BUFFER

Changes since v1:
1. Use a fixed size buffer instead of kmalloc allocated during update
scan mode
2. Remove a write to read only register ADC_HS (COCO bit)

 drivers/iio/adc/Kconfig     |   2 +
 drivers/iio/adc/vf610_adc.c | 105 +++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 100 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 7c55658..660f790 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -337,6 +337,8 @@ config TWL6030_GPADC
 config VF610_ADC
 	tristate "Freescale vf610 ADC driver"
 	depends on OF
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	help
 	  Say yes here to support for Vybrid board analog-to-digital converter.
 	  Since the IP is used for i.MX6SLX, the driver also support i.MX6SLX.
diff --git a/drivers/iio/adc/vf610_adc.c b/drivers/iio/adc/vf610_adc.c
index 23b8fb9..887a7ba 100644
--- a/drivers/iio/adc/vf610_adc.c
+++ b/drivers/iio/adc/vf610_adc.c
@@ -34,8 +34,11 @@
 #include <linux/err.h>
 
 #include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
 #include <linux/iio/sysfs.h>
-#include <linux/iio/driver.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
 
 /* This will be the driver name the kernel reports */
 #define DRIVER_NAME "vf610-adc"
@@ -170,6 +173,7 @@ struct vf610_adc {
 	u32 sample_freq_avail[5];
 
 	struct completion completion;
+	u16 buffer[8];
 };
 
 static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 };
@@ -505,12 +509,24 @@ static const struct iio_chan_spec_ext_info vf610_ext_info[] = {
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |	\
 				BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
 	.ext_info = vf610_ext_info,				\
+	.scan_index = (_idx),			\
+	.scan_type = {					\
+		.sign = 'u',				\
+		.realbits = 12,				\
+		.storagebits = 16,			\
+	},						\
 }
 
 #define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) {	\
 	.type = (_chan_type),	\
 	.channel = (_idx),		\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),	\
+	.scan_index = (_idx),					\
+	.scan_type = {						\
+		.sign = 'u',					\
+		.realbits = 12,					\
+		.storagebits = 16,				\
+	},							\
 }
 
 static const struct iio_chan_spec vf610_adc_iio_channels[] = {
@@ -531,6 +547,7 @@ static const struct iio_chan_spec vf610_adc_iio_channels[] = {
 	VF610_ADC_CHAN(14, IIO_VOLTAGE),
 	VF610_ADC_CHAN(15, IIO_VOLTAGE),
 	VF610_ADC_TEMPERATURE_CHAN(26, IIO_TEMP),
+	IIO_CHAN_SOFT_TIMESTAMP(32),
 	/* sentinel */
 };
 
@@ -559,13 +576,20 @@ static int vf610_adc_read_data(struct vf610_adc *info)
 
 static irqreturn_t vf610_adc_isr(int irq, void *dev_id)
 {
-	struct vf610_adc *info = (struct vf610_adc *)dev_id;
+	struct iio_dev *indio_dev = (struct iio_dev *)dev_id;
+	struct vf610_adc *info = iio_priv(indio_dev);
 	int coco;
 
 	coco = readl(info->regs + VF610_REG_ADC_HS);
 	if (coco & VF610_ADC_HS_COCO0) {
 		info->value = vf610_adc_read_data(info);
-		complete(&info->completion);
+		if (iio_buffer_enabled(indio_dev)) {
+			info->buffer[0] = info->value;
+			iio_push_to_buffers_with_timestamp(indio_dev,
+					info->buffer, iio_get_time_ns());
+			iio_trigger_notify_done(indio_dev->trig);
+		} else
+			complete(&info->completion);
 	}
 
 	return IRQ_HANDLED;
@@ -613,8 +637,12 @@ static int vf610_read_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_RAW:
 	case IIO_CHAN_INFO_PROCESSED:
 		mutex_lock(&indio_dev->mlock);
-		reinit_completion(&info->completion);
+		if (iio_buffer_enabled(indio_dev)) {
+			mutex_unlock(&indio_dev->mlock);
+			return -EBUSY;
+		}
 
+		reinit_completion(&info->completion);
 		hc_cfg = VF610_ADC_ADCHC(chan->channel);
 		hc_cfg |= VF610_ADC_AIEN;
 		writel(hc_cfg, info->regs + VF610_REG_ADC_HC0);
@@ -694,6 +722,60 @@ static int vf610_write_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+static int vf610_adc_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct vf610_adc *info = iio_priv(indio_dev);
+	unsigned int channel;
+	int ret;
+	int val;
+
+	ret = iio_triggered_buffer_postenable(indio_dev);
+	if (ret)
+		return ret;
+
+	val = readl(info->regs + VF610_REG_ADC_GC);
+	val |= VF610_ADC_ADCON;
+	writel(val, info->regs + VF610_REG_ADC_GC);
+
+	channel = find_first_bit(indio_dev->active_scan_mask,
+						indio_dev->masklength);
+
+	val = VF610_ADC_ADCHC(channel);
+	val |= VF610_ADC_AIEN;
+
+	writel(val, info->regs + VF610_REG_ADC_HC0);
+
+	return 0;
+}
+
+static int vf610_adc_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct vf610_adc *info = iio_priv(indio_dev);
+	unsigned int hc_cfg = 0;
+	int val, ret;
+
+	val = readl(info->regs + VF610_REG_ADC_GC);
+	val &= ~VF610_ADC_ADCON;
+	writel(val, info->regs + VF610_REG_ADC_GC);
+
+	hc_cfg |= VF610_ADC_CONV_DISABLE;
+	hc_cfg &= ~VF610_ADC_AIEN;
+
+	writel(hc_cfg, info->regs + VF610_REG_ADC_HC0);
+
+	ret = iio_triggered_buffer_predisable(indio_dev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
+	.postenable = &vf610_adc_buffer_postenable,
+	.predisable = &vf610_adc_buffer_predisable,
+	.validate_scan_mask = &iio_validate_scan_mask_onehot,
+};
+
 static int vf610_adc_reg_access(struct iio_dev *indio_dev,
 			unsigned reg, unsigned writeval,
 			unsigned *readval)
@@ -753,7 +835,7 @@ static int vf610_adc_probe(struct platform_device *pdev)
 
 	ret = devm_request_irq(info->dev, irq,
 				vf610_adc_isr, 0,
-				dev_name(&pdev->dev), info);
+				dev_name(&pdev->dev), indio_dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed requesting irq, irq = %d\n", irq);
 		return ret;
@@ -806,15 +888,23 @@ static int vf610_adc_probe(struct platform_device *pdev)
 	vf610_adc_cfg_init(info);
 	vf610_adc_hw_init(info);
 
+	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+					NULL, &iio_triggered_buffer_setup_ops);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Couldn't initialise the buffer\n");
+		goto error_iio_device_register;
+	}
+
 	ret = iio_device_register(indio_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Couldn't register the device.\n");
-		goto error_iio_device_register;
+		goto error_adc_buffer_init;
 	}
 
 	return 0;
 
-
+error_adc_buffer_init:
+	iio_triggered_buffer_cleanup(indio_dev);
 error_iio_device_register:
 	clk_disable_unprepare(info->clk);
 error_adc_clk_enable:
@@ -829,6 +919,7 @@ static int vf610_adc_remove(struct platform_device *pdev)
 	struct vf610_adc *info = iio_priv(indio_dev);
 
 	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
 	regulator_disable(info->vref);
 	clk_disable_unprepare(info->clk);
 
-- 
2.5.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/