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@xxxxxxxxx>
> ---
>  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)
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