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Message-ID: <20150817135606.GB2940@Sanchayan-Arch.toradex.int>
Date: Mon, 17 Aug 2015 19:26:06 +0530
From: maitysanchayan@...il.com
To: Jonathan Cameron <jic23@...nel.org>
Cc: linux-iio@...r.kernel.org, stefan@...er.ch, B38611@...escale.com,
pmeerw@...erw.net, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3] iio: adc: vf610: Add IIO buffer support for Vybrid ADC
Hello Jonathan,
On 15-08-15 21:24:01, Jonathan Cameron wrote:
> On 11/08/15 10:05, 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.
> >
> > Signed-off-by: Sanchayan Maity <maitysanchayan@...il.com>
> Hi Sanchayan,
>
> Very nearly there. One little point to do with the buffer handling.
> Basically I don't think you want anything in the preenable or
> postdisable hooks, just in the 'internal' ones.
>
> Jonathan
> > ---
> > drivers/iio/adc/Kconfig | 2 +
> > drivers/iio/adc/vf610_adc.c | 102 +++++++++++++++++++++++++++++++++++++++++---
> > 2 files changed, 97 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..de62c48 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 +722,57 @@ 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;
> > +}
> > +
>
> These are suppose to be pair wise matched, so anything set up
> in postenable has to be torn down in predisable.
> Likewise, preenable setup torn down in postdisable.
>
> The distinction is meant to be that a query will return that the
> buffer is enabled from a point between the pre and post enable
> and return that it is disabled from a point between the pre and
> post disable. Actually locks are held so there may no longer
> be a window where it matters, but best to keep to convention.
>
> I think you want the postdisable -> predisable and then call the
> standard predisable from there.
Ok. I guess I understood. So the postdisable code actually should
go into predisable and while taking care of mutex locking.
The way I was reasoning wanting to enable the continuous sampling
after the buffer is enabled and then after buffer is disabled,
stopping it. With your explanation it makes sense that I should
have it in predisable.
Thank you for the feedback. I will incoporate the above change
and send the new version.
- Sanchayan.
>
> > +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 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_reg_access(struct iio_dev *indio_dev,
> > unsigned reg, unsigned writeval,
> > unsigned *readval)
> > @@ -753,7 +832,7 @@ 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 +885,23 @@ 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 +916,7 @@ 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);
> >
> >
>
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