[PATCH] Add continuous sampling with IIO buffers for Vybrid

[PATCH] Add continuous sampling with IIO buffers for Vybrid

[Sanchayan Maity]

Hello,

This patch adds support for continuous sampling provided by the
ADC block on Vybrid by leveraging the IIO triggered buffer and
IIO sysfs trigger infrastructure.

The patch has been tested on Colibri VF50 and VF61 on shawn's
tree for-next branch with the patches [1] and [2] applied.

The below script was used for testing.

#!/bin/sh
echo 0 > /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage8_en
echo 0 > /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage9_en
echo 1 > /sys/bus/iio/devices/iio:device0/scan_elements/in_temp_en
echo 1 > /sys/bus/iio/devices/iio:device0/scan_elements/in_timestamp_en
echo 0 > /sys/bus/iio/devices/iio_sysfs_trigger/add_trigger
/home/root/generic_buffer -n 4003b000.adc -t sysfstrig0 -l 512 -c 10
echo 0 > /sys/bus/iio/devices/iio:device0/scan_elements/in_timestamp_en
echo 0 > /sys/bus/iio/devices/iio:device0/scan_elements/in_temp_en
echo 0 > /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage8_en
echo 0 > /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage9_en

Feedback and comments are most welcome.

Had some additional queries.

On shawn's tree, using imx_v6_v7_defconfig and running the above
script on VF50 gives me the following trace:

[  199.976662] INFO: rcu_sched self-detected stall on CPU
[  199.982015]  0: (2600 ticks this GP) idle=181/140000000000002/0 softirq=14591/14591 fqs=0
[  199.990406]   (t=2600 jiffies g=11024 c=11023 q=20)
[  199.995430] rcu_sched kthread starved for 2600 jiffies! g11024 c11023 f0x0
[  200.002523] Task dump for CPU 0:
[  200.005830] generic_buffer  R running      0   414    413 0x00000002
[  200.012370] Backtrace:
[  200.014974] [<80013708>] (dump_backtrace) from [<800138fc>] (show_stack+0x18/0x1c)
[  200.022665]  r7:80ae0f40 r6:80b374e8 r5:0000019d r4:85fdd080
[  200.028578] [<800138e4>] (show_stack) from [<800557bc>] (sched_show_task+0x11c/0x22c)
[  200.036555] [<800556a0>] (sched_show_task) from [<80057efc>] (dump_cpu_task+0x34/0x44)
[  200.044596]  r6:80000193 r5:80ae0f40 r4:00000000
[  200.049432] [<80057ec8>] (dump_cpu_task) from [<800820f8>] (rcu_dump_cpu_stacks+0x8c/0xd0)
[  200.057821]  r5:80ae0f40 r4:00000000
[  200.061563] [<8008206c>] (rcu_dump_cpu_stacks) from [<80085b88>] (rcu_check_callbacks+0x4dc/0x854)
[  200.070655]  r9:80ae0f40 r8:0720b000 r7:80ad09cc r6:80ae0f40 r5:80acd600 r4:87cd8600
[  200.078701] [<800856ac>] (rcu_check_callbacks) from [<80088820>] (update_process_times+0x40/0x6c)
[  200.087699]  r10:87cd5fc0 r9:8009a180 r8:80aedb80 r7:0000002e r6:8764c12d r5:00000000
[  200.095800]  r4:85fdd080
[  200.098462] [<800887e0>] (update_process_times) from [<8009a17c>] (tick_sched_handle.isra.19+0x4c/0x50)
[  200.108049]  r5:85e85d40 r4:87cd5fc0
[  200.111822] [<8009a130>] (tick_sched_handle.isra.19) from [<8009a1e4>] (tick_sched_timer+0x64/0xb0)
[  200.121098] [<8009a180>] (tick_sched_timer) from [<80089220>] (__hrtimer_run_queues+0xc4/0x1cc)
[  200.129989]  r7:0000002e r6:87649b3a r5:87cd5d00 r4:87cd5c80
[  200.135915] [<8008915c>] (__hrtimer_run_queues) from [<80089950>] (hrtimer_interrupt+0xc8/0x21c)
[  200.144898]  r10:87cd5d38 r9:87cd5d58 r8:87cd5c80 r7:87cd5cc0 r6:ffffffff r5:7fffffff
[  200.153061]  r4:00000003
[  200.155752] [<80089888>] (hrtimer_interrupt) from [<8054dcd0>] (gt_clockevent_interrupt+0x48/0x74)
[  200.164905]  r10:85e85f80 r9:87806000 r8:00000010 r7:87817b40 r6:87808100 r5:87cdab40
[  200.173082]  r4:00000001
[  200.175758] [<8054dc88>] (gt_clockevent_interrupt) from [<8007cab0>] (handle_percpu_devid_irq+0x8c/0xac)
[  200.185442]  r5:80aedd20 r4:87cdab40
[  200.189215] [<8007ca24>] (handle_percpu_devid_irq) from [<800786e4>] (generic_handle_irq+0x30/0x44)
[  200.198460]  r9:87806000 r8:00000001 r7:85e85e30 r6:80ad0b30 r5:00000010 r4:00000010
[  200.206567] [<800786b4>] (generic_handle_irq) from [<80078a08>] (__handle_domain_irq+0x6c/0xe8)
[  200.215455]  r5:00000010 r4:80acb5fc
[  200.219219] [<8007899c>] (__handle_domain_irq) from [<80009560>] (gic_handle_irq+0x28/0x68)
[  200.227759]  r9:87806000 r8:00000001 r7:88002100 r6:80ad0ca8 r5:8800210c r4:85e85d40
[  200.235861] [<80009538>] (gic_handle_irq) from [<80014564>] (__irq_svc+0x44/0x5c)
[  200.243526] Exception stack(0x85e85d40 to 0x85e85d88)
[  200.248720] 5d40: 00000001 85fdd548 00000000 85fdd080 00000202 00000000 80ad0b30 80ad0080
[  200.257104] 5d60: 00000001 87806000 85e85f80 85e85dcc 80c9f5d0 85e85d88 8006b5a0 8002ff80
[  200.265468] 5d80: 60000113 ffffffff
[  200.269056]  r7:85e85d74 r6:ffffffff r5:60000113 r4:8002ff80
[  200.274995] [<8002fec8>] (__do_softirq) from [<800304c8>] (irq_exit+0xc4/0x138)
[  200.282486]  r10:85e85f80 r9:87806000 r8:00000001 r7:00000000 r6:80ad0b30 r5:00000000
[  200.290660]  r4:80acb5fc
[  200.293345] [<80030404>] (irq_exit) from [<80078a10>] (__handle_domain_irq+0x74/0xe8)
[  200.301367]  r5:00000000 r4:80acb5fc
[  200.305135] [<8007899c>] (__handle_domain_irq) from [<80009560>] (gic_handle_irq+0x28/0x68)
[  200.313680]  r9:85efc60c r8:85e4bc00 r7:88002100 r6:80ad0ca8 r5:8800210c r4:85e85e30
[  200.321777] [<80009538>] (gic_handle_irq) from [<80014564>] (__irq_svc+0x44/0x5c)
[  200.329442] Exception stack(0x85e85e30 to 0x85e85e78)
[  200.334628] 5e20:                                     00000001 85fdd548 00000000 85fdd080
[  200.343010] 5e40: 00000001 803ce7c8 85e4bc00 00000000 85e4bc00 85efc60c 85e85f80 85e85e84
[  200.351384] 5e60: 80c9f5d0 85e85e78 8006b5a0 803ce7e8 60000013 ffffffff
[  200.358131]  r7:85e85e64 r6:ffffffff r5:60000013 r4:803ce7e8
[  200.364087] [<803ce7c8>] (dev_attr_store) from [<801739a0>] (sysfs_kf_write+0x54/0x58)
[  200.372217] [<8017394c>] (sysfs_kf_write) from [<80172b60>] (kernfs_fop_write+0xc4/0x1a8)
[  200.380579]  r7:00000000 r6:00000000 r5:00000001 r4:85efc600
[  200.386518] [<80172a9c>] (kernfs_fop_write) from [<80104f10>] (__vfs_write+0x2c/0xe0)
[  200.394535]  r10:00000000 r9:85e84000 r8:8000fc84 r7:85e85f80 r6:76fa3000 r5:85e85f80
[  200.402696]  r4:85fb2500
[  200.405376] [<80104ee4>] (__vfs_write) from [<801057b4>] (vfs_write+0x98/0x16c)
[  200.412865]  r8:8000fc84 r7:85e85f80 r6:76fa3000 r5:00000001 r4:85fb2500
[  200.419878] [<8010571c>] (vfs_write) from [<80106028>] (SyS_write+0x4c/0xa8)
[  200.427072]  r8:8000fc84 r7:00000001 r6:76fa3000 r5:85fb2500 r4:85fb2500
[  200.434099] [<80105fdc>] (SyS_write) from [<8000faa0>] (ret_fast_syscall+0x0/0x54)
[  200.441848]  r7:00000004 r6:76fa3000 r5:00000001 r4:002be960

On shawn's tree, using our own defconfig it all works fine.

The RCU related configs in imx_v6_v7_defconfig are:
# RCU Subsystem
CONFIG_TREE_RCU=y
# CONFIG_RCU_EXPERT is not set
CONFIG_SRCU=y
# CONFIG_TASKS_RCU is not set
CONFIG_RCU_STALL_COMMON=y
# CONFIG_TREE_RCU_TRACE is not set
# CONFIG_RCU_NOCB_CPU is not set
# CONFIG_RCU_EXPEDITE_BOOT is not set
# RCU Debugging
CONFIG_PROVE_RCU=y
# CONFIG_PROVE_RCU_REPEATEDLY is not set
# CONFIG_SPARSE_RCU_POINTER is not set
# CONFIG_RCU_TORTURE_TEST is not set
CONFIG_RCU_CPU_STALL_TIMEOUT=21
CONFIG_RCU_CPU_STALL_INFO=y
# CONFIG_RCU_TRACE is not set
# CONFIG_RCU_EQS_DEBUG is not set

The RCU configs in our own defconfig are:
# RCU Subsystem
CONFIG_TINY_RCU=y
CONFIG_SRCU=y
# CONFIG_TASKS_RCU is not set
# CONFIG_RCU_STALL_COMMON is not set
# CONFIG_TREE_RCU_TRACE is not set
CONFIG_RCU_KTHREAD_PRIO=0
# RCU Debugging
# CONFIG_SPARSE_RCU_POINTER is not set
# CONFIG_RCU_TORTURE_TEST is not set
# CONFIG_RCU_TRACE is not set

With the above second set of configs I do not encounter any problems.

I do not have any knowledge on the RCU front, can someone also comment
with regards to that? Perhaps I am doing something wrong in the driver?
My guess would be those RCU STALL configs?

[1]. https://lkml.org/lkml/2015/5/27/350
[2]. https://lkml.org/lkml/2015/7/14/395

Thanks & Regards,
Sanchayan Maity.

Sanchayan Maity (1):
  iio: adc: vf610: Add IIO buffer support for Vybrid ADC

 drivers/iio/adc/Kconfig     |   4 ++
 drivers/iio/adc/vf610_adc.c | 122 +++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 120 insertions(+), 6 deletions(-)

-- 
2.5.0

[PATCH] 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@gmail.com>
---
 drivers/iio/adc/Kconfig     |   4 ++
 drivers/iio/adc/vf610_adc.c | 122 +++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 120 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 7c55658..4661241 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -337,6 +337,10 @@ config TWL6030_GPADC
 config VF610_ADC
 	tristate "Freescale vf610 ADC driver"
 	depends on OF
+	select IIO_BUFFER
+	select IIO_TRIGGER
+	select IIO_SYSFS_TRIGGER
+	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..af72b9a 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;
 };
 
 static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 };
@@ -505,12 +509,22 @@ 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,				\
+	.address = (_idx),				\
+	.scan_index = (_idx),			\
+	.scan_type.sign = 'u',			\
+	.scan_type.realbits = 12,		\
+	.scan_type.storagebits = 16,	\
 }
 
 #define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) {	\
 	.type = (_chan_type),	\
 	.channel = (_idx),		\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),	\
+	.address = (_idx),						\
+	.scan_index = (_idx),					\
+	.scan_type.sign = 'u',					\
+	.scan_type.realbits = 12,				\
+	.scan_type.storagebits = 16,			\
 }
 
 static const struct iio_chan_spec vf610_adc_iio_channels[] = {
@@ -531,6 +545,7 @@ 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 +574,21 @@ 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;
+			writel(0, info->regs + VF610_REG_ADC_HS);
+			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;
@@ -612,6 +635,9 @@ static int vf610_read_raw(struct iio_dev *indio_dev,
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 	case IIO_CHAN_INFO_PROCESSED:
+		if (iio_buffer_enabled(indio_dev))
+			return -EBUSY;
+
 		mutex_lock(&indio_dev->mlock);
 		reinit_completion(&info->completion);
 
@@ -694,6 +720,81 @@ 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_postdisable(struct iio_dev *indio_dev)
+{
+	struct vf610_adc *info = iio_priv(indio_dev);
+	unsigned int hc_cfg = 0;
+	int val;
+
+	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);
+
+	return 0;
+}
+
+static int vf610_adc_update_scan_mode(struct iio_dev *indio_dev,
+	const unsigned long *scan_mask)
+{
+	struct vf610_adc *info = iio_priv(indio_dev);
+
+	kfree(info->buffer);
+	info->buffer = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+	if (!info->buffer)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
+	.postenable = &vf610_adc_buffer_postenable,
+	.predisable = &iio_triggered_buffer_predisable,
+	.postdisable = &vf610_adc_buffer_postdisable,
+	.validate_scan_mask = &iio_validate_scan_mask_onehot,
+};
+
+static int vf610_adc_buffer_init(struct iio_dev *indio_dev)
+{
+	return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+		NULL, &iio_triggered_buffer_setup_ops);
+}
+
+static void vf610_adc_buffer_remove(struct iio_dev *indio_dev)
+{
+	iio_triggered_buffer_cleanup(indio_dev);
+}
+
 static int vf610_adc_reg_access(struct iio_dev *indio_dev,
 			unsigned reg, unsigned writeval,
 			unsigned *readval)
@@ -714,6 +815,7 @@ static const struct iio_info vf610_adc_iio_info = {
 	.read_raw = &vf610_read_raw,
 	.write_raw = &vf610_write_raw,
 	.debugfs_reg_access = &vf610_adc_reg_access,
+	.update_scan_mode = &vf610_adc_update_scan_mode,
 	.attrs = &vf610_attribute_group,
 };
 
@@ -753,7 +855,7 @@ 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 +908,22 @@ static int vf610_adc_probe(struct platform_device *pdev)
 	vf610_adc_cfg_init(info);
 	vf610_adc_hw_init(info);
 
+	ret = vf610_adc_buffer_init(indio_dev);
+	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:
+	vf610_adc_buffer_remove(indio_dev);
 error_iio_device_register:
 	clk_disable_unprepare(info->clk);
 error_adc_clk_enable:
@@ -829,6 +938,7 @@ static int vf610_adc_remove(struct platform_device *pdev)
 	struct vf610_adc *info = iio_priv(indio_dev);
 
 	iio_device_unregister(indio_dev);
+	vf610_adc_buffer_remove(indio_dev);
 	regulator_disable(info->vref);
 	clk_disable_unprepare(info->clk);
 
-- 
2.5.0

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

[Peter Meerwald]

On Mon, 3 Aug 2015, Sanchayan Maity wrote:

> 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.

comments below
 
> Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
> ---
>  drivers/iio/adc/Kconfig     |   4 ++
>  drivers/iio/adc/vf610_adc.c | 122 +++++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 120 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 7c55658..4661241 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -337,6 +337,10 @@ config TWL6030_GPADC
>  config VF610_ADC
>  	tristate "Freescale vf610 ADC driver"
>  	depends on OF
> +	select IIO_BUFFER
> +	select IIO_TRIGGER
> +	select IIO_SYSFS_TRIGGER
> +	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..af72b9a 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;
>  };
>  
>  static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 };
> @@ -505,12 +509,22 @@ 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,				\
> +	.address = (_idx),				\

address is not used, no need to set it

> +	.scan_index = (_idx),			\

often this is written .scan_type = {.sign = 'u', ...}

> +	.scan_type.sign = 'u',			\
> +	.scan_type.realbits = 12,		\
> +	.scan_type.storagebits = 16,	\
>  }
>  
>  #define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) {	\
>  	.type = (_chan_type),	\
>  	.channel = (_idx),		\
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),	\
> +	.address = (_idx),						\
> +	.scan_index = (_idx),					\
> +	.scan_type.sign = 'u',					\
> +	.scan_type.realbits = 12,				\
> +	.scan_type.storagebits = 16,			\
>  }
>  
>  static const struct iio_chan_spec vf610_adc_iio_channels[] = {
> @@ -531,6 +545,7 @@ 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 +574,21 @@ 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;
> +			writel(0, info->regs + VF610_REG_ADC_HS);
> +			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;
> @@ -612,6 +635,9 @@ static int vf610_read_raw(struct iio_dev *indio_dev,
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
>  	case IIO_CHAN_INFO_PROCESSED:
> +		if (iio_buffer_enabled(indio_dev))
> +			return -EBUSY;
> +
>  		mutex_lock(&indio_dev->mlock);
>  		reinit_completion(&info->completion);
>  
> @@ -694,6 +720,81 @@ 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_postdisable(struct iio_dev *indio_dev)
> +{
> +	struct vf610_adc *info = iio_priv(indio_dev);
> +	unsigned int hc_cfg = 0;
> +	int val;
> +
> +	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);
> +
> +	return 0;
> +}
> +
> +static int vf610_adc_update_scan_mode(struct iio_dev *indio_dev,
> +	const unsigned long *scan_mask)
> +{
> +	struct vf610_adc *info = iio_priv(indio_dev);
> +
> +	kfree(info->buffer);

only one channel can be read (onehot), why not use a fixed size buffer 
(one u16, perhaps as a local variable in _adc_isr()?

> +	info->buffer = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> +	if (!info->buffer)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
> +	.postenable = &vf610_adc_buffer_postenable,
> +	.predisable = &iio_triggered_buffer_predisable,
> +	.postdisable = &vf610_adc_buffer_postdisable,
> +	.validate_scan_mask = &iio_validate_scan_mask_onehot,
> +};
> +
> +static int vf610_adc_buffer_init(struct iio_dev *indio_dev)
> +{
> +	return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
> +		NULL, &iio_triggered_buffer_setup_ops);
> +}
> +
> +static void vf610_adc_buffer_remove(struct iio_dev *indio_dev)
> +{
> +	iio_triggered_buffer_cleanup(indio_dev);
> +}
> +
>  static int vf610_adc_reg_access(struct iio_dev *indio_dev,
>  			unsigned reg, unsigned writeval,
>  			unsigned *readval)
> @@ -714,6 +815,7 @@ static const struct iio_info vf610_adc_iio_info = {
>  	.read_raw = &vf610_read_raw,
>  	.write_raw = &vf610_write_raw,
>  	.debugfs_reg_access = &vf610_adc_reg_access,
> +	.update_scan_mode = &vf610_adc_update_scan_mode,
>  	.attrs = &vf610_attribute_group,
>  };
>  
> @@ -753,7 +855,7 @@ 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 +908,22 @@ static int vf610_adc_probe(struct platform_device *pdev)
>  	vf610_adc_cfg_init(info);
>  	vf610_adc_hw_init(info);
>  
> +	ret = vf610_adc_buffer_init(indio_dev);
> +	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:
> +	vf610_adc_buffer_remove(indio_dev);
>  error_iio_device_register:
>  	clk_disable_unprepare(info->clk);
>  error_adc_clk_enable:
> @@ -829,6 +938,7 @@ static int vf610_adc_remove(struct platform_device *pdev)
>  	struct vf610_adc *info = iio_priv(indio_dev);
>  
>  	iio_device_unregister(indio_dev);
> +	vf610_adc_buffer_remove(indio_dev);
>  	regulator_disable(info->vref);
>  	clk_disable_unprepare(info->clk);
>  
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)

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

[Duan Andy]

From: Sanchayan Maity <maitysanchayan@gmail.com> Sent: Monday, August 03, 2015 11:10 PM
> To: jic23@kernel.org; linux-iio@vger.kernel.org
> Cc: stefan@agner.ch; Duan Fugang-B38611; hofrat@osadl.org;
> sanjeev_sharma@mentor.com; Estevam Fabio-R49496; knaack.h@gmx.de;
> lars@metafoo.de; pmeerw@pmeerw.net; antoine.tenart@free-electrons.com;
> linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> Sanchayan Maity
> Subject: [PATCH] iio: adc: vf610: Add IIO buffer support for Vybrid ADC
> 
> 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@gmail.com>
> ---
>  drivers/iio/adc/Kconfig     |   4 ++
>  drivers/iio/adc/vf610_adc.c | 122
> +++++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 120 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index
> 7c55658..4661241 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -337,6 +337,10 @@ config TWL6030_GPADC  config VF610_ADC
>  	tristate "Freescale vf610 ADC driver"
>  	depends on OF
> +	select IIO_BUFFER
> +	select IIO_TRIGGER
> +	select IIO_SYSFS_TRIGGER
> +	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..af72b9a 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;
>  };
> 
>  static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 }; @@ -505,12
> +509,22 @@ 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,				\
> +	.address = (_idx),				\
> +	.scan_index = (_idx),			\
> +	.scan_type.sign = 'u',			\
> +	.scan_type.realbits = 12,		\
> +	.scan_type.storagebits = 16,	\
>  }
> 
>  #define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) {	\
>  	.type = (_chan_type),	\
>  	.channel = (_idx),		\
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),	\
> +	.address = (_idx),						\
> +	.scan_index = (_idx),					\
> +	.scan_type.sign = 'u',					\
> +	.scan_type.realbits = 12,				\
> +	.scan_type.storagebits = 16,			\
>  }
> 
>  static const struct iio_chan_spec vf610_adc_iio_channels[] = { @@ -531,6
> +545,7 @@ 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 +574,21 @@ 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;
> +			writel(0, info->regs + VF610_REG_ADC_HS);
The register is read only. After ADC_Rn is read, the coco bit is cleared.

> +			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;
> @@ -612,6 +635,9 @@ static int vf610_read_raw(struct iio_dev *indio_dev,
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
>  	case IIO_CHAN_INFO_PROCESSED:
> +		if (iio_buffer_enabled(indio_dev))
> +			return -EBUSY;
> +
>  		mutex_lock(&indio_dev->mlock);
>  		reinit_completion(&info->completion);
> 
> @@ -694,6 +720,81 @@ 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_postdisable(struct iio_dev *indio_dev) {
> +	struct vf610_adc *info = iio_priv(indio_dev);
> +	unsigned int hc_cfg = 0;
> +	int val;
> +
> +	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);
> +
> +	return 0;
> +}
> +
> +static int vf610_adc_update_scan_mode(struct iio_dev *indio_dev,
> +	const unsigned long *scan_mask)
> +{
> +	struct vf610_adc *info = iio_priv(indio_dev);
> +
> +	kfree(info->buffer);
> +	info->buffer = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> +	if (!info->buffer)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops
> = {
> +	.postenable = &vf610_adc_buffer_postenable,
> +	.predisable = &iio_triggered_buffer_predisable,
> +	.postdisable = &vf610_adc_buffer_postdisable,
> +	.validate_scan_mask = &iio_validate_scan_mask_onehot, };
> +
> +static int vf610_adc_buffer_init(struct iio_dev *indio_dev) {
> +	return iio_triggered_buffer_setup(indio_dev,
> &iio_pollfunc_store_time,
> +		NULL, &iio_triggered_buffer_setup_ops); }
> +
> +static void vf610_adc_buffer_remove(struct iio_dev *indio_dev) {
> +	iio_triggered_buffer_cleanup(indio_dev);
> +}
> +
>  static int vf610_adc_reg_access(struct iio_dev *indio_dev,
>  			unsigned reg, unsigned writeval,
>  			unsigned *readval)
> @@ -714,6 +815,7 @@ static const struct iio_info vf610_adc_iio_info = {
>  	.read_raw = &vf610_read_raw,
>  	.write_raw = &vf610_write_raw,
>  	.debugfs_reg_access = &vf610_adc_reg_access,
> +	.update_scan_mode = &vf610_adc_update_scan_mode,
>  	.attrs = &vf610_attribute_group,
>  };
> 
> @@ -753,7 +855,7 @@ 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 +908,22 @@ static int vf610_adc_probe(struct platform_device
> *pdev)
>  	vf610_adc_cfg_init(info);
>  	vf610_adc_hw_init(info);
> 
> +	ret = vf610_adc_buffer_init(indio_dev);
> +	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:
> +	vf610_adc_buffer_remove(indio_dev);
>  error_iio_device_register:
>  	clk_disable_unprepare(info->clk);
>  error_adc_clk_enable:
> @@ -829,6 +938,7 @@ static int vf610_adc_remove(struct platform_device
> *pdev)
>  	struct vf610_adc *info = iio_priv(indio_dev);
> 
>  	iio_device_unregister(indio_dev);
> +	vf610_adc_buffer_remove(indio_dev);
>  	regulator_disable(info->vref);
>  	clk_disable_unprepare(info->clk);
> 
> --
> 2.5.0

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

[maitysanchayan]

Hello,

On 15-08-04 03:18:46, Duan Andy wrote:
> From: Sanchayan Maity <maitysanchayan@gmail.com> Sent: Monday, August 03, 2015 11:10 PM
> > To: jic23@kernel.org; linux-iio@vger.kernel.org
> > Cc: stefan@agner.ch; Duan Fugang-B38611; hofrat@osadl.org;
> > sanjeev_sharma@mentor.com; Estevam Fabio-R49496; knaack.h@gmx.de;
> > lars@metafoo.de; pmeerw@pmeerw.net; antoine.tenart@free-electrons.com;
> > linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> > Sanchayan Maity
> > Subject: [PATCH] iio: adc: vf610: Add IIO buffer support for Vybrid ADC
> > 
> > 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@gmail.com>
> > ---
> >  drivers/iio/adc/Kconfig     |   4 ++
> >  drivers/iio/adc/vf610_adc.c | 122
> > +++++++++++++++++++++++++++++++++++++++++---
> >  2 files changed, 120 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index
> > 7c55658..4661241 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -337,6 +337,10 @@ config TWL6030_GPADC  config VF610_ADC
> >  	tristate "Freescale vf610 ADC driver"
> >  	depends on OF
> > +	select IIO_BUFFER
> > +	select IIO_TRIGGER
> > +	select IIO_SYSFS_TRIGGER
> > +	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..af72b9a 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;
> >  };
> > 
> >  static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 }; @@ -505,12
> > +509,22 @@ 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,				\
> > +	.address = (_idx),				\
> > +	.scan_index = (_idx),			\
> > +	.scan_type.sign = 'u',			\
> > +	.scan_type.realbits = 12,		\
> > +	.scan_type.storagebits = 16,	\
> >  }
> > 
> >  #define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) {	\
> >  	.type = (_chan_type),	\
> >  	.channel = (_idx),		\
> >  	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),	\
> > +	.address = (_idx),						\
> > +	.scan_index = (_idx),					\
> > +	.scan_type.sign = 'u',					\
> > +	.scan_type.realbits = 12,				\
> > +	.scan_type.storagebits = 16,			\
> >  }
> > 
> >  static const struct iio_chan_spec vf610_adc_iio_channels[] = { @@ -531,6
> > +545,7 @@ 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 +574,21 @@ 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;
> > +			writel(0, info->regs + VF610_REG_ADC_HS);
> The register is read only. After ADC_Rn is read, the coco bit is cleared.

Right. This crept in from a different implementation which I was trying with
PDB and perhaps a wrong interpretation of the TRM.

Will fix.

Regards,
Sanchayan.

(snip)