Re: [PATCH 2/3] iio: adc: at91-sama5d2_adc: add hw trigger and buffer support

[Ludovic Desroches]

On Wed, Apr 19, 2017 at 11:20:44AM +0300, Eugen Hristev wrote:
> Added support for the external hardware trigger on pin ADTRG,
> integrated the three possible edge triggers into the subsystem
> and created buffer management for data retrieval
> 
> Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
Acked-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>

> ---
>  drivers/iio/adc/at91-sama5d2_adc.c | 207 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 204 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
> index e10dca3..09a8c3d 100644
> --- a/drivers/iio/adc/at91-sama5d2_adc.c
> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
> @@ -23,8 +23,15 @@
>  #include <linux/platform_device.h>
>  #include <linux/sched.h>
>  #include <linux/wait.h>
> +#include <linux/slab.h>
> +
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +
>  #include <linux/regulator/consumer.h>
>  
>  /* Control Register */
> @@ -132,6 +139,17 @@
>  #define AT91_SAMA5D2_PRESSR	0xbc
>  /* Trigger Register */
>  #define AT91_SAMA5D2_TRGR	0xc0
> +/* Mask for TRGMOD field of TRGR register */
> +#define AT91_SAMA5D2_TRGR_TRGMOD_MASK GENMASK(2, 0)
> +/* No trigger, only software trigger can start conversions */
> +#define AT91_SAMA5D2_TRGR_TRGMOD_NO_TRIGGER 0
> +/* Trigger Mode external trigger rising edge */
> +#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_RISE 1
> +/* Trigger Mode external trigger falling edge */
> +#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_FALL 2
> +/* Trigger Mode external trigger any edge */
> +#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_ANY 3
> +
>  /* Correction Select Register */
>  #define AT91_SAMA5D2_COSR	0xd0
>  /* Correction Value Register */
> @@ -145,14 +163,20 @@
>  /* Version Register */
>  #define AT91_SAMA5D2_VERSION	0xfc
>  
> +#define AT91_SAMA5D2_HW_TRIG_CNT 3
> +#define AT91_SAMA5D2_SINGLE_CHAN_CNT 12
> +#define AT91_SAMA5D2_DIFF_CHAN_CNT 6
> +
>  #define AT91_SAMA5D2_CHAN_SINGLE(num, addr)				\
>  	{								\
>  		.type = IIO_VOLTAGE,					\
>  		.channel = num,						\
>  		.address = addr,					\
> +		.scan_index = num,					\
>  		.scan_type = {						\
>  			.sign = 'u',					\
>  			.realbits = 12,					\
> +			.storagebits = 16,				\
>  		},							\
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
>  		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> @@ -168,9 +192,11 @@
>  		.channel = num,						\
>  		.channel2 = num2,					\
>  		.address = addr,					\
> +		.scan_index = num + AT91_SAMA5D2_SINGLE_CHAN_CNT,	\
>  		.scan_type = {						\
>  			.sign = 's',					\
>  			.realbits = 12,					\
> +			.storagebits = 16,				\
>  		},							\
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
>  		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> @@ -188,18 +214,26 @@ struct at91_adc_soc_info {
>  	unsigned			max_sample_rate;
>  };
>  
> +struct at91_adc_trigger {
> +	char				*name;
> +	unsigned int			trgmod_value;
> +};
> +
>  struct at91_adc_state {
>  	void __iomem			*base;
>  	int				irq;
>  	struct clk			*per_clk;
>  	struct regulator		*reg;
>  	struct regulator		*vref;
> +	u16				*buffer;
>  	int				vref_uv;
>  	const struct iio_chan_spec	*chan;
>  	bool				conversion_done;
>  	u32				conversion_value;
>  	struct at91_adc_soc_info	soc_info;
>  	wait_queue_head_t		wq_data_available;
> +	struct iio_trigger		**trig;
> +	const struct at91_adc_trigger	*trigger_list;
>  	/*
>  	 * lock to prevent concurrent 'single conversion' requests through
>  	 * sysfs.
> @@ -207,6 +241,21 @@ struct at91_adc_state {
>  	struct mutex			lock;
>  };
>  
> +static const struct at91_adc_trigger at91_adc_trigger_list[] = {
> +	{
> +		.name = "external-rising",
> +		.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_RISE,
> +	},
> +	{
> +		.name = "external-falling",
> +		.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_FALL,
> +	},
> +	{
> +		.name = "external-any",
> +		.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_ANY,
> +	},
> +};
> +
>  static const struct iio_chan_spec at91_adc_channels[] = {
>  	AT91_SAMA5D2_CHAN_SINGLE(0, 0x50),
>  	AT91_SAMA5D2_CHAN_SINGLE(1, 0x54),
> @@ -226,8 +275,141 @@ static const struct iio_chan_spec at91_adc_channels[] = {
>  	AT91_SAMA5D2_CHAN_DIFF(6, 7, 0x68),
>  	AT91_SAMA5D2_CHAN_DIFF(8, 9, 0x70),
>  	AT91_SAMA5D2_CHAN_DIFF(10, 11, 0x78),
> +	IIO_CHAN_SOFT_TIMESTAMP(AT91_SAMA5D2_SINGLE_CHAN_CNT
> +				+ AT91_SAMA5D2_DIFF_CHAN_CNT + 1),
>  };
>  
> +static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
> +{
> +	struct iio_dev *indio = iio_trigger_get_drvdata(trig);
> +	struct at91_adc_state *st = iio_priv(indio);
> +	u32 status = at91_adc_readl(st, AT91_SAMA5D2_TRGR);
> +	u8 bit;
> +	int i;
> +
> +	/* clear TRGMOD */
> +	status &= ~AT91_SAMA5D2_TRGR_TRGMOD_MASK;
> +
> +	/* if we are disabling the trigger, it's enough to clear TRGMOD */
> +	if (!state) {
> +		at91_adc_writel(st, AT91_SAMA5D2_TRGR, status);
> +		kfree(st->buffer);
> +		return 0;
> +	}
> +
> +	st->buffer = kmalloc(indio->scan_bytes, GFP_KERNEL);
> +	if (!st->buffer)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < AT91_SAMA5D2_HW_TRIG_CNT; i++) {
> +		if (!strstr(trig->name, st->trigger_list[i].name)) {
> +			status |= st->trigger_list[i].trgmod_value;
> +			break;
> +		}
> +	}
> +
> +	/* setup hw trigger */
> +	at91_adc_writel(st, AT91_SAMA5D2_TRGR, status);
> +
> +	for_each_set_bit(bit, indio->active_scan_mask, indio->num_channels) {
> +		struct iio_chan_spec const *chan = indio->channels + bit;
> +
> +		at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
> +		at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct iio_trigger_ops at91_adc_trigger_ops = {
> +	.owner = THIS_MODULE,
> +	.set_trigger_state = &at91_adc_configure_trigger,
> +};
> +
> +static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *indio,
> +						     char *trigger_name)
> +{
> +	struct iio_trigger *trig;
> +	int ret;
> +
> +	trig = devm_iio_trigger_alloc(&indio->dev, "%s-dev%d-%s", indio->name,
> +				      indio->id, trigger_name);
> +	if (!trig)
> +		return NULL;
> +
> +	trig->dev.parent = indio->dev.parent;
> +	iio_trigger_set_drvdata(trig, indio);
> +	trig->ops = &at91_adc_trigger_ops;
> +
> +	ret = devm_iio_trigger_register(&indio->dev, trig);
> +
> +	if (ret)
> +		return NULL;
> +
> +	return trig;
> +}
> +
> +static int at91_adc_trigger_init(struct iio_dev *indio)
> +{
> +	struct at91_adc_state *st = iio_priv(indio);
> +	int i;
> +
> +	st->trig = devm_kzalloc(&indio->dev,
> +				AT91_SAMA5D2_HW_TRIG_CNT * sizeof(*st->trig),
> +				GFP_KERNEL);
> +
> +	if (!st->trig) {
> +		dev_err(&indio->dev, "could not allocate trig list memory\n");
> +		return -ENOMEM;
> +	}
> +
> +	for (i = 0; i < AT91_SAMA5D2_HW_TRIG_CNT; i++) {
> +		st->trig[i] = at91_adc_allocate_trigger(indio,
> +						st->trigger_list[i].name);
> +		if (!st->trig[i]) {
> +			dev_err(&indio->dev,
> +				"could not allocate trigger %d\n", i);
> +			return -ENOMEM;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio = pf->indio_dev;
> +	struct at91_adc_state *st = iio_priv(indio);
> +	int i = 0;
> +	u8 bit;
> +
> +	for_each_set_bit(bit, indio->active_scan_mask, indio->num_channels) {
> +		struct iio_chan_spec const *chan = indio->channels + bit;
> +
> +		st->buffer[i] = at91_adc_readl(st, chan->address);
> +		i++;
> +	}
> +
> +	iio_push_to_buffers_with_timestamp(indio, st->buffer, pf->timestamp);
> +
> +	iio_trigger_notify_done(indio->trig);
> +
> +	/* Needed to ACK the DRDY interruption */
> +	at91_adc_readl(st, AT91_SAMA5D2_LCDR);
> +
> +	enable_irq(st->irq);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int at91_adc_buffer_init(struct iio_dev *indio)
> +{
> +	return devm_iio_triggered_buffer_setup(&indio->dev, indio,
> +			&iio_pollfunc_store_time,
> +			&at91_adc_trigger_handler, NULL);
> +}
> +
>  static unsigned at91_adc_startup_time(unsigned startup_time_min,
>  				      unsigned adc_clk_khz)
>  {
> @@ -293,14 +475,19 @@ static irqreturn_t at91_adc_interrupt(int irq, void *private)
>  	u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
>  	u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);
>  
> -	if (status & imr) {
> +	if (!(status & imr))
> +		return IRQ_NONE;
> +
> +	if (iio_buffer_enabled(indio)) {
> +		disable_irq_nosync(irq);
> +		iio_trigger_poll(indio->trig);
> +	} else {
>  		st->conversion_value = at91_adc_readl(st, st->chan->address);
>  		st->conversion_done = true;
>  		wake_up_interruptible(&st->wq_data_available);
> -		return IRQ_HANDLED;
>  	}
>  
> -	return IRQ_NONE;
> +	return IRQ_HANDLED;
>  }
>  
>  static int at91_adc_read_raw(struct iio_dev *indio_dev,
> @@ -406,6 +593,8 @@ static int at91_adc_probe(struct platform_device *pdev)
>  
>  	st = iio_priv(indio_dev);
>  
> +	st->trigger_list = at91_adc_trigger_list;
> +
>  	ret = of_property_read_u32(pdev->dev.of_node,
>  				   "atmel,min-sample-rate-hz",
>  				   &st->soc_info.min_sample_rate);
> @@ -499,6 +688,18 @@ static int at91_adc_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, indio_dev);
>  
> +	ret = at91_adc_buffer_init(indio_dev);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "couldn't initialize the buffer.\n");
> +		goto per_clk_disable_unprepare;
> +	}
> +
> +	ret = at91_adc_trigger_init(indio_dev);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "couldn't setup the triggers.\n");
> +		goto per_clk_disable_unprepare;
> +	}
> +
>  	ret = iio_device_register(indio_dev);
>  	if (ret < 0)
>  		goto per_clk_disable_unprepare;
> -- 
> 2.7.4
>