On Thu, 21 Oct 2021 14:59:50 +0200
Lars-Peter Clausen <lars@xxxxxxxxxx> wrote:
> In some setups the IRQ signal of the XADC might not be wired to the host
> system. The driver currently requires that an interrupt is specified. Make
> the interrupt optional so the driver can be used in such setups where the
> interrupt is not connected.
>
> Since both the internal triggers as well as events depend on the interrupt
> being connected both are not available when the interrupt is not connected.
>
> Buffered access is still supported even without an interrupt since an
> external trigger can be used.
>
> The IRQ is only optional when using the AXI interface, since the PCAP
> interface needs the IRQ for reading and writing registers.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Applied to the togreg branch of iio.git and pushed out as testing.
Thanks,
Jonathan
> ---
> drivers/iio/adc/xilinx-xadc-core.c | 62 +++++++++++++++++++-----------
> 1 file changed, 40 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
> index 83bea5ef765d..2aa4278ecba7 100644
> --- a/drivers/iio/adc/xilinx-xadc-core.c
> +++ b/drivers/iio/adc/xilinx-xadc-core.c
> @@ -107,6 +107,7 @@ static const unsigned int XADC_ZYNQ_UNMASK_TIMEOUT = 500;
> #define XADC_AXI_INT_ALARM_MASK 0x3c0f
>
> #define XADC_FLAGS_BUFFERED BIT(0)
> +#define XADC_FLAGS_IRQ_OPTIONAL BIT(1)
>
> /*
> * The XADC hardware supports a samplerate of up to 1MSPS. Unfortunately it does
> @@ -562,7 +563,7 @@ static const struct xadc_ops xadc_7s_axi_ops = {
> .get_dclk_rate = xadc_axi_get_dclk,
> .update_alarm = xadc_axi_update_alarm,
> .interrupt_handler = xadc_axi_interrupt_handler,
> - .flags = XADC_FLAGS_BUFFERED,
> + .flags = XADC_FLAGS_BUFFERED | XADC_FLAGS_IRQ_OPTIONAL,
> .type = XADC_TYPE_S7,
> };
>
> @@ -573,7 +574,7 @@ static const struct xadc_ops xadc_us_axi_ops = {
> .get_dclk_rate = xadc_axi_get_dclk,
> .update_alarm = xadc_axi_update_alarm,
> .interrupt_handler = xadc_axi_interrupt_handler,
> - .flags = XADC_FLAGS_BUFFERED,
> + .flags = XADC_FLAGS_BUFFERED | XADC_FLAGS_IRQ_OPTIONAL,
> .type = XADC_TYPE_US,
> };
>
> @@ -1182,7 +1183,7 @@ static const struct of_device_id xadc_of_match_table[] = {
> MODULE_DEVICE_TABLE(of, xadc_of_match_table);
>
> static int xadc_parse_dt(struct iio_dev *indio_dev, struct device_node *np,
> - unsigned int *conf)
> + unsigned int *conf, int irq)
> {
> struct device *dev = indio_dev->dev.parent;
> struct xadc *xadc = iio_priv(indio_dev);
> @@ -1195,6 +1196,7 @@ static int xadc_parse_dt(struct iio_dev *indio_dev, struct device_node *np,
> u32 ext_mux_chan;
> u32 reg;
> int ret;
> + int i;
>
> *conf = 0;
>
> @@ -1273,6 +1275,14 @@ static int xadc_parse_dt(struct iio_dev *indio_dev, struct device_node *np,
> }
> of_node_put(chan_node);
>
> + /* No IRQ => no events */
> + if (irq <= 0) {
> + for (i = 0; i < num_channels; i++) {
> + channels[i].event_spec = NULL;
> + channels[i].num_event_specs = 0;
> + }
> + }
> +
> indio_dev->num_channels = num_channels;
> indio_dev->channels = devm_krealloc(dev, channels,
> sizeof(*channels) * num_channels,
> @@ -1307,6 +1317,7 @@ static int xadc_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> const struct of_device_id *id;
> + const struct xadc_ops *ops;
> struct iio_dev *indio_dev;
> unsigned int bipolar_mask;
> unsigned int conf0;
> @@ -1322,9 +1333,12 @@ static int xadc_probe(struct platform_device *pdev)
> if (!id)
> return -EINVAL;
>
> - irq = platform_get_irq(pdev, 0);
> - if (irq <= 0)
> - return -ENXIO;
> + ops = id->data;
> +
> + irq = platform_get_irq_optional(pdev, 0);
> + if (irq < 0 &&
> + (irq != -ENXIO || !(ops->flags & XADC_FLAGS_IRQ_OPTIONAL)))
> + return irq;
>
> indio_dev = devm_iio_device_alloc(dev, sizeof(*xadc));
> if (!indio_dev)
> @@ -1345,7 +1359,7 @@ static int xadc_probe(struct platform_device *pdev)
> indio_dev->modes = INDIO_DIRECT_MODE;
> indio_dev->info = &xadc_info;
>
> - ret = xadc_parse_dt(indio_dev, dev->of_node, &conf0);
> + ret = xadc_parse_dt(indio_dev, dev->of_node, &conf0, irq);
> if (ret)
> return ret;
>
> @@ -1357,14 +1371,16 @@ static int xadc_probe(struct platform_device *pdev)
> if (ret)
> return ret;
>
> - xadc->convst_trigger = xadc_alloc_trigger(indio_dev, "convst");
> - if (IS_ERR(xadc->convst_trigger))
> - return PTR_ERR(xadc->convst_trigger);
> + if (irq > 0) {
> + xadc->convst_trigger = xadc_alloc_trigger(indio_dev, "convst");
> + if (IS_ERR(xadc->convst_trigger))
> + return PTR_ERR(xadc->convst_trigger);
>
> - xadc->samplerate_trigger = xadc_alloc_trigger(indio_dev,
> - "samplerate");
> - if (IS_ERR(xadc->samplerate_trigger))
> - return PTR_ERR(xadc->samplerate_trigger);
> + xadc->samplerate_trigger = xadc_alloc_trigger(indio_dev,
> + "samplerate");
> + if (IS_ERR(xadc->samplerate_trigger))
> + return PTR_ERR(xadc->samplerate_trigger);
> + }
> }
>
> xadc->clk = devm_clk_get(dev, NULL);
> @@ -1396,15 +1412,17 @@ static int xadc_probe(struct platform_device *pdev)
> }
> }
>
> - ret = devm_request_irq(dev, irq, xadc->ops->interrupt_handler, 0,
> - dev_name(dev), indio_dev);
> - if (ret)
> - return ret;
> + if (irq > 0) {
> + ret = devm_request_irq(dev, irq, xadc->ops->interrupt_handler,
> + 0, dev_name(dev), indio_dev);
> + if (ret)
> + return ret;
>
> - ret = devm_add_action_or_reset(dev, xadc_cancel_delayed_work,
> - &xadc->zynq_unmask_work);
> - if (ret)
> - return ret;
> + ret = devm_add_action_or_reset(dev, xadc_cancel_delayed_work,
> + &xadc->zynq_unmask_work);
> + if (ret)
> + return ret;
> + }
>
> ret = xadc->ops->setup(pdev, indio_dev, irq);
> if (ret)
