Message-ID: <520CBEC6.8010400@kernel.org>
Date:	Thu, 15 Aug 2013 12:43:02 +0100
From:	Jonathan Cameron <jic23@...nel.org>
To:	Zubair Lutfullah <zubair.lutfullah@...il.com>
CC:	jic23@....ac.uk, dmitry.torokhov@...il.com,
	linux-iio@...r.kernel.org, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org, bigeasy@...utronix.de,
	gregkh@...uxfoundation.org, Russ.Dill@...com
Subject: Re: [PATCH 4/4] iio: ti_am335x_adc: Add continuous sampling and trigger
 support

On 08/13/13 21:05, Zubair Lutfullah wrote:
> Previously the driver had only one-shot reading functionality.
> This patch adds triggered buffer support to the driver.
> A buffer of samples can now be read via /dev/iio.
> Any IIO trigger can be used to start acquisition.
>
> Patil Rachna (TI) laid the ground work for ADC HW register access.
> Russ Dill (TI) fixed bugs in the driver relevant to FIFOs and IRQs.
>
> I fixed channel scanning so multiple ADC channels can be read
> simultaneously and pushed to userspace. Restructured the driver
> to fit IIO ABI. And added trigger support.
>
> Signed-off-by: Zubair Lutfullah <zubair.lutfullah@...il.com>
> Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Signed-off-by: Russ Dill <Russ.Dill@...com>

Hi,

Whilst the below review is based on what we have here, I tried to apply it
to the latest iio.git togreg branch (which for this driver should be
much the same as staging-next and hence linux-next).  It's not even
close and I can't immediately spot where some of the changes came
from.  Have I missed a precursor patch or is this based on an
older version of this driver?

Note I'd also like a much more detailed description in the patch header.
This is an unusual driver in that it is pushing an entire fifo on a single
trigger into the iio buffers.  Normally it is one trigger / one scan. I have
no particular problem with hybrid software / hardware buffer approach but
it should certainly be clearly documented!

I would also expect an option for the trigger to be supplied from the
chip itself based on fifo watershead interrupts.  Thus the adc could be
operated at full rate without losing data.  As you described in a previous
email this is much more similar to a one shot osciloscope trigger where it
grabs the next set of readings.  Now this is an interesting option, but
it isn't the standard one for IIO.  I'd be interested to see a proposal
for adding this functionality to the core in a more general fashion.
(I actually like this idea a lot!)

A quick thought on interface would be to have

iio:device0/buffer/oneshot_length
(need not actually be the same as the buffer_length - longer and it would
 require userspace to have grabbed the data out in the meantime, shorter and
 we could grab a series before userspace read any of them).
iio:device0/buffer/buffer_enable_oneshot
(capture would then occur until oneshot_length had been acquired - then stop
 - if the trigger that is driving capture wants to be gated by another signal
   that would not be that hard to do either).

Could be neffarouious and abuse one of the poll variants to indicate when
our oneshot sample is done (this was discussed before as we had a watershed
interrupt on a ring buffer at one point).

For now I'd be much happier if this driver conformed to more or less the
standard form with the one exception being that the 'trigger' is based on
the fifo threshold and so it might appear to grab multiple scans of the
enabled channels for each trigger (which is fine). Even if we provide the
functionality sketched out above, it would still be as core functionality, not
in the driver as you have done here.

Sorry I can't really take the patch as is because we would end up with one
driver with a substantially different ABI to all others and that would make
thinks very fiddly for userspace.

Jonathan
.

> ---
>  drivers/iio/adc/ti_am335x_adc.c      |  353 ++++++++++++++++++++++++++++------
>  include/linux/mfd/ti_am335x_tscadc.h |   12 ++
>  2 files changed, 303 insertions(+), 62 deletions(-)
>
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index 3ceac3e..0d7e313 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -24,16 +24,28 @@
>  #include <linux/iio/iio.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> -#include <linux/iio/machine.h>
>  #include <linux/iio/driver.h>
> +#include <linux/wait.h>
> +#include <linux/sched.h>
>
>  #include <linux/mfd/ti_am335x_tscadc.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
>
>  struct tiadc_device {
>  	struct ti_tscadc_dev *mfd_tscadc;
>  	int channels;
>  	u8 channel_line[8];
>  	u8 channel_step[8];
> +	struct work_struct poll_work;
> +	wait_queue_head_t wq_data_avail;
> +	bool data_avail;
> +	u32 *inputbuffer;
> +	int sample_count;
> +	int irq;
> +	int buffer_en_ch_steps;
>  };
>
>  static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
> @@ -56,27 +68,28 @@ static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
>  	return step_en;
>  }
>
> -static void tiadc_step_config(struct tiadc_device *adc_dev)
> +static void tiadc_step_config(struct iio_dev *indio_dev)
>  {
> +	struct tiadc_device *adc_dev = iio_priv(indio_dev);
>  	unsigned int stepconfig;
> -	int i, steps;
> +	int i, steps, chan;
>
>  	/*
>  	 * There are 16 configurable steps and 8 analog input
>  	 * lines available which are shared between Touchscreen and ADC.
> -	 *
>  	 * Steps backwards i.e. from 16 towards 0 are used by ADC
>  	 * depending on number of input lines needed.
>  	 * Channel would represent which analog input
>  	 * needs to be given to ADC to digitalize data.
>  	 */
> -
>  	steps = TOTAL_STEPS - adc_dev->channels;
> -	stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
> +	if (iio_buffer_enabled(indio_dev))
> +		stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
> +					| STEPCONFIG_MODE_SWCNT;
> +	else
> +		stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
>
>  	for (i = 0; i < adc_dev->channels; i++) {
> -		int chan;
> -
>  		chan = adc_dev->channel_line[i];
>  		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
>  				stepconfig | STEPCONFIG_INP(chan));
> @@ -85,7 +98,203 @@ static void tiadc_step_config(struct tiadc_device *adc_dev)
>  		adc_dev->channel_step[i] = steps;
>  		steps++;
>  	}
> +}
> +
> +static irqreturn_t tiadc_irq(int irq, void *private)
> +{
> +	struct iio_dev *idev = private;
> +	struct tiadc_device *adc_dev = iio_priv(idev);
> +	unsigned int status, config;
> +	status = tiadc_readl(adc_dev, REG_IRQSTATUS);
> +
> +	/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
> +	if (status & IRQENB_FIFO1OVRRUN) {
> +		config = tiadc_readl(adc_dev, REG_CTRL);
> +		config &= ~(CNTRLREG_TSCSSENB);
> +		tiadc_writel(adc_dev, REG_CTRL, config);
> +		tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN |
> +				IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
> +		tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
> +	} else if (status & IRQENB_FIFO1THRES) {

I'd normally expect this interrupt to drive a trigger that in turn results in
the data being dumped into the software buffers.

> +		/* Wake adc_work that pushes FIFO data to iio buffer */
> +		tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
> +		adc_dev->data_avail = 1;
> +		wake_up_interruptible(&adc_dev->wq_data_avail);
> +	} else
> +		return IRQ_NONE;
> +
> +	status = tiadc_readl(adc_dev, REG_IRQSTATUS);
> +	if (status == false)
> +			return IRQ_HANDLED;
> +	else
> +		return IRQ_NONE;
> +}
> +
> +static irqreturn_t tiadc_trigger_h(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct tiadc_device *adc_dev = iio_priv(indio_dev);
> +	unsigned int config;
> +
> +	schedule_work(&adc_dev->poll_work);
> +	am335x_tsc_se_set(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
> +	if (adc_dev->mfd_tscadc->tsc_cell == -1) {
> +		config = tiadc_readl(adc_dev, REG_CTRL);
> +		tiadc_writel(adc_dev, REG_CTRL,	config & ~CNTRLREG_TSCSSENB);
> +		tiadc_writel(adc_dev, REG_CTRL,	config |  CNTRLREG_TSCSSENB);
> +	}
> +
> +	tiadc_writel(adc_dev,  REG_IRQSTATUS, IRQENB_FIFO1THRES |
> +			 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
> +	tiadc_writel(adc_dev,  REG_IRQENABLE, IRQENB_FIFO1THRES
> +				| IRQENB_FIFO1OVRRUN);
> +
> +	iio_trigger_notify_done(indio_dev->trig);
Are you actually done?  What happens if another trigger turns up in the
meantime?  I'd expect this to occur only after the results of the trigger
have been handled.
> +	return IRQ_HANDLED;
> +}
> +
> +static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
> +{
Don't have pointless wrappers like this.
> +	return iio_sw_buffer_preenable(indio_dev);
> +}
> +
> +static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
> +{
> +	struct tiadc_device *adc_dev = iio_priv(indio_dev);
> +	struct iio_buffer *buffer = indio_dev->buffer;
> +	unsigned int enb = 0, stepnum;
> +	u8 bit;
> +
> +	tiadc_step_config(indio_dev);
> +	for_each_set_bit(bit, buffer->scan_mask,
> +			adc_dev->channels) {
> +		struct iio_chan_spec const *chan = indio_dev->channels + bit;
> +		/*
> +		 * There are a total of 16 steps available
> +		 * that are shared between ADC and touchscreen.
> +		 * We start configuring from step 16 to 0 incase of
> +		 * ADC. Hence the relation between input channel
> +		 * and step for ADC would be as below.
> +		 */
> +		stepnum = chan->channel + 9;
> +		enb |= (1 << stepnum);
> +	}
> +	adc_dev->buffer_en_ch_steps = enb;
> +
> +	return iio_triggered_buffer_postenable(indio_dev);
> +}
> +
> +static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
> +{
> +	struct tiadc_device *adc_dev = iio_priv(indio_dev);
> +	int fifo1count, i, read, config;
> +
> +	if (adc_dev->mfd_tscadc->tsc_cell == -1) {
> +		config = tiadc_readl(adc_dev, REG_CTRL);
> +		config &= ~(CNTRLREG_TSCSSENB);
> +		tiadc_writel(adc_dev, REG_CTRL, config);
> +	} else
> +		tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB_TC);
> +
> +	tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
> +				IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
> +
> +	/* Flush FIFO of any leftover data */
> +	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> +	for (i = 0; i < fifo1count; i++)
> +		read = tiadc_readl(adc_dev, REG_FIFO1);
> +
> +	return iio_triggered_buffer_predisable(indio_dev);
> +}
> +
> +static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
> +{
> +	struct tiadc_device *adc_dev = iio_priv(indio_dev);
> +	int config;
> +
> +	tiadc_step_config(indio_dev);
> +	if (adc_dev->mfd_tscadc->tsc_cell == -1) {
> +		config = tiadc_readl(adc_dev, REG_CTRL);
> +		tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
> +	.preenable = &tiadc_buffer_preenable,
> +	.postenable = &tiadc_buffer_postenable,
> +	.predisable = &tiadc_buffer_predisable,
> +	.postdisable = &tiadc_buffer_postdisable,
> +};
> +
> +static void tiadc_adc_work(struct work_struct *work_s)
> +{
> +	struct tiadc_device *adc_dev =
> +		container_of(work_s, struct tiadc_device, poll_work);
> +	struct iio_dev *indio_dev = iio_priv_to_dev(adc_dev);
> +	struct iio_buffer *buffer = indio_dev->buffer;
> +	int i, j, k, fifo1count, read;
> +	unsigned int config;
So normally we'd just fill with one sample hence for this case
I'd expect to push out whatever samples are in the fifo right now
then return.  The next trigger would grab the next lot etc.

> +	int size_to_acquire = buffer->access->get_length(buffer);
> +	int sample_count = 0;
> +	u32 *data;
> +
> +	adc_dev->data_avail = 0;
> +	data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> +	if (data == NULL)
> +		goto out;
> +
> +	while (sample_count < size_to_acquire) {
> +		tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
> +		tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
> +
> +		wait_event_interruptible(adc_dev->wq_data_avail,
> +					(adc_dev->data_avail == 1));
> +		adc_dev->data_avail = 0;
> +
> +		fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> +		if (fifo1count * sizeof(u32) <
> +				buffer->access->get_bytes_per_datum(buffer))
> +			continue;
> +
> +		sample_count = sample_count + fifo1count;
> +		for (k = 0; k < fifo1count; k = k + i) {
> +			for (i = 0, j = 0; i < (indio_dev->scan_bytes)/4; i++) {
> +				read = tiadc_readl(adc_dev, REG_FIFO1);
> +				data[i] = read & FIFOREAD_DATA_MASK;
> +			}
> +			iio_push_to_buffers(indio_dev, (u8 *) data);
> +		}
> +	}
> +out:
> +	tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
> +				IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
> +	am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
> +	if (adc_dev->mfd_tscadc->tsc_cell == -1) {
> +		config = tiadc_readl(adc_dev, REG_CTRL);
> +		tiadc_writel(adc_dev, REG_CTRL,	config & ~CNTRLREG_TSCSSENB);
> +	}
> +}
> +
> +irqreturn_t tiadc_iio_pollfunc(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct tiadc_device *adc_dev = iio_priv(indio_dev);
> +	int i, fifo1count, read;
> +
> +	tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
> +				IRQENB_FIFO1OVRRUN |
> +				IRQENB_FIFO1UNDRFLW));
> +
> +	/* Flush FIFO before trigger */
> +	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> +	for (i = 0; i < fifo1count; i++)
> +		read = tiadc_readl(adc_dev, REG_FIFO1);
>
> +	return IRQ_WAKE_THREAD;
>  }
>
>  static const char * const chan_name_ain[] = {
> @@ -120,13 +329,13 @@ static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
>  		chan->channel = adc_dev->channel_line[i];
>  		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>  		chan->datasheet_name = chan_name_ain[chan->channel];
> +		chan->scan_index = i;
>  		chan->scan_type.sign = 'u';
>  		chan->scan_type.realbits = 12;
>  		chan->scan_type.storagebits = 32;
>  	}
>
>  	indio_dev->channels = chan_array;
> -
>  	return 0;
>  }
>
> @@ -141,58 +350,51 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
>  {
>  	struct tiadc_device *adc_dev = iio_priv(indio_dev);
>  	int i, map_val;
> -	unsigned int fifo1count, read, stepid;
> -	u32 step = UINT_MAX;
> -	bool found = false;
> -	u32 step_en;
> -	unsigned long timeout = jiffies + usecs_to_jiffies
> -				(IDLE_TIMEOUT * adc_dev->channels);
> -	step_en = get_adc_step_mask(adc_dev);
> -	am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
> -
> -	/* Wait for ADC sequencer to complete sampling */
> -	while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
> -		if (time_after(jiffies, timeout))
> -			return -EAGAIN;
> -		}
> -	map_val = chan->channel + TOTAL_CHANNELS;
> -
> -	/*
> -	 * When the sub-system is first enabled,
> -	 * the sequencer will always start with the
> -	 * lowest step (1) and continue until step (16).
> -	 * For ex: If we have enabled 4 ADC channels and
> -	 * currently use only 1 out of them, the
> -	 * sequencer still configures all the 4 steps,
> -	 * leading to 3 unwanted data.
> -	 * Hence we need to flush out this data.
> -	 */
> -
> -	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
> -		if (chan->channel == adc_dev->channel_line[i]) {
> -			step = adc_dev->channel_step[i];
> -			break;
> -		}
> -	}
> -	if (WARN_ON_ONCE(step == UINT_MAX))
> -		return -EINVAL;
> -
> -	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> -	for (i = 0; i < fifo1count; i++) {
> -		read = tiadc_readl(adc_dev, REG_FIFO1);
> -		stepid = read & FIFOREAD_CHNLID_MASK;
> -		stepid = stepid >> 0x10;
> +	unsigned int fifo1count, read, stepid, step_en;
>
> -		if (stepid == map_val) {
> -			read = read & FIFOREAD_DATA_MASK;
> -			found = true;
> -			*val = read;
> +	if (iio_buffer_enabled(indio_dev))
> +		return -EBUSY;
> +	else {
> +		unsigned long timeout = jiffies + usecs_to_jiffies
> +					(IDLE_TIMEOUT * adc_dev->channels);
> +		step_en = get_adc_step_mask(adc_dev);
> +		am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
> +
> +		/* Wait for ADC sequencer to complete sampling */
> +		while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
> +			if (time_after(jiffies, timeout))
> +				return -EAGAIN;
> +			}
> +		map_val = chan->channel + TOTAL_CHANNELS;
> +
> +		/*
> +		 * When the sub-system is first enabled,
> +		 * the sequencer will always start with the
> +		 * lowest step (1) and continue until step (16).
> +		 * For ex: If we have enabled 4 ADC channels and
> +		 * currently use only 1 out of them, the
> +		 * sequencer still configures all the 4 steps,
> +		 * leading to 3 unwanted data.
> +		 * Hence we need to flush out this data.
> +		 */
> +
> +		*val = -1;
> +		fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> +		for (i = 0; i < fifo1count; i++) {
> +			read = tiadc_readl(adc_dev, REG_FIFO1);
> +			stepid = read & FIFOREAD_CHNLID_MASK;
> +			stepid = stepid >> 0x10;
> +
> +			if (stepid == map_val) {
> +				read = read & FIFOREAD_DATA_MASK;
> +				*val = read;
> +			}
>  		}
> +		if (*val != -1)
> +			return IIO_VAL_INT;
> +		else
> +			return -EAGAIN;
>  	}
> -
> -	if (found == false)
> -		return -EBUSY;
> -	return IIO_VAL_INT;
>  }
>
>  static const struct iio_info tiadc_info = {
> @@ -231,26 +433,45 @@ static int tiadc_probe(struct platform_device *pdev)
>  		channels++;
>  	}
>  	adc_dev->channels = channels;
> +	adc_dev->irq = adc_dev->mfd_tscadc->irq;
>
>  	indio_dev->dev.parent = &pdev->dev;
>  	indio_dev->name = dev_name(&pdev->dev);
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  	indio_dev->info = &tiadc_info;
>
> -	tiadc_step_config(adc_dev);
> +	tiadc_step_config(indio_dev);
> +	tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
>
>  	err = tiadc_channel_init(indio_dev, adc_dev->channels);
>  	if (err < 0)
>  		goto err_free_device;
>
> -	err = iio_device_register(indio_dev);
> +	INIT_WORK(&adc_dev->poll_work, &tiadc_adc_work);
> +	init_waitqueue_head(&adc_dev->wq_data_avail);
> +
> +	err = request_irq(adc_dev->irq, tiadc_irq, IRQF_SHARED,
> +		indio_dev->name, indio_dev);
>  	if (err)
>  		goto err_free_channels;
>
> +	err = iio_triggered_buffer_setup(indio_dev, &tiadc_iio_pollfunc,
> +			&tiadc_trigger_h, &tiadc_buffer_setup_ops);
> +	if (err)
> +		goto err_free_irq;
> +
> +	err = iio_device_register(indio_dev);
> +	if (err)
> +		goto err_buffer_unregister;
> +
>  	platform_set_drvdata(pdev, indio_dev);
>
>  	return 0;
>
> +err_buffer_unregister:
> +	iio_buffer_unregister(indio_dev);
> +err_free_irq:
> +	free_irq(adc_dev->irq, indio_dev);
>  err_free_channels:
>  	tiadc_channels_remove(indio_dev);
>  err_free_device:
> @@ -265,7 +486,9 @@ static int tiadc_remove(struct platform_device *pdev)
>  	struct tiadc_device *adc_dev = iio_priv(indio_dev);
>  	u32 step_en;
>
> +	free_irq(adc_dev->irq, indio_dev);
>  	iio_device_unregister(indio_dev);
> +	iio_buffer_unregister(indio_dev);
>  	tiadc_channels_remove(indio_dev);
>
>  	step_en = get_adc_step_mask(adc_dev);
> @@ -303,10 +526,16 @@ static int tiadc_resume(struct device *dev)
>
>  	/* Make sure ADC is powered up */
>  	restore = tiadc_readl(adc_dev, REG_CTRL);
> -	restore &= ~(CNTRLREG_POWERDOWN);
> +	restore &= ~(CNTRLREG_TSCSSENB);
>  	tiadc_writel(adc_dev, REG_CTRL, restore);
>
> -	tiadc_step_config(adc_dev);
> +	tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
> +	tiadc_step_config(indio_dev);
> +
> +	/* Make sure ADC is powered up */
> +	restore &= ~(CNTRLREG_POWERDOWN);
> +	restore |= CNTRLREG_TSCSSENB;
> +	tiadc_writel(adc_dev, REG_CTRL, restore);
>
>  	return 0;
>  }
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index e2db978..14f75a4 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -46,6 +46,9 @@
>  /* Step Enable */
>  #define STEPENB_MASK		(0x1FFFF << 0)
>  #define STEPENB(val)		((val) << 0)
> +#define ENB(val)			(1 << (val))
> +#define STPENB_STEPENB		STEPENB(0x1FFFF)
> +#define STPENB_STEPENB_TC	STEPENB(0x1FFF)
>
>  /* IRQ enable */
>  #define IRQENB_HW_PEN		BIT(0)
> @@ -53,12 +56,15 @@
>  #define IRQENB_FIFO0OVRRUN	BIT(3)
>  #define IRQENB_FIFO0UNDRFLW	BIT(4)
>  #define IRQENB_FIFO1THRES	BIT(5)
> +#define IRQENB_FIFO1OVRRUN	BIT(6)
> +#define IRQENB_FIFO1UNDRFLW	BIT(7)
>  #define IRQENB_PENUP		BIT(9)
>
>  /* Step Configuration */
>  #define STEPCONFIG_MODE_MASK	(3 << 0)
>  #define STEPCONFIG_MODE(val)	((val) << 0)
>  #define STEPCONFIG_MODE_HWSYNC	STEPCONFIG_MODE(2)
> +#define STEPCONFIG_MODE_SWCNT	STEPCONFIG_MODE(1)
>  #define STEPCONFIG_AVG_MASK	(7 << 2)
>  #define STEPCONFIG_AVG(val)	((val) << 2)
>  #define STEPCONFIG_AVG_16	STEPCONFIG_AVG(4)
> @@ -126,6 +132,8 @@
>  #define	MAX_CLK_DIV		7
>  #define TOTAL_STEPS		16
>  #define TOTAL_CHANNELS		8
> +#define FIFO1_THRESHOLD		19
> +#define FIFO_SIZE		64
>
>  /*
>  * ADC runs at 3MHz, and it takes
> @@ -155,6 +163,10 @@ struct ti_tscadc_dev {
>
>  	/* adc device */
>  	struct adc_device *adc;
> +
> +	/* Context save */
> +	unsigned int irqstat;
> +	unsigned int ctrl;
>  };
>
>  static inline struct ti_tscadc_dev *ti_tscadc_dev_get(struct platform_device *p)
>
--
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