Hello,
On 15-08-04 09:32:23, Peter Meerwald 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
>
> gave some ill advise regarding buffer size..
>
> > > 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()?
>
> fixed size buffer might still be a good idea but it has to be 16 bytes:
> one u16 + padding (6 bytes) + timestamp (8 bytes aligned at 8 bytes
> offset)
>
Will implement, test it and change accordingly.
Thanks & Regards,
Sanchayan.
(snip)
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