From: Ahmad Fatoum <a.fatoum@pengutronix.de> To: Jonathan Cameron <jic23@kernel.org>, Lars-Peter Clausen <lars@metafoo.de>, Peter Meerwald-Stadler <pmeerw@pmeerw.net>, Maxime Coquelin <mcoquelin.stm32@gmail.com>, Alexandre Torgue <alexandre.torgue@st.com> Cc: kernel@pengutronix.de, Holger Assmann <has@pengutronix.de>, Fabrice Gasnier <fabrice.gasnier@foss.st.com>, Ahmad Fatoum <a.fatoum@pengutronix.de>, linux-iio@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] iio: adc: stm32-adc: enable timestamping for non-DMA usage Date: Fri, 22 Jan 2021 12:33:55 +0100 [thread overview] Message-ID: <20210122113355.32384-1-a.fatoum@pengutronix.de> (raw) For non-DMA usage, we have an easy way to associate a timestamp with a sample: iio_pollfunc_store_time stores a timestamp in the primary trigger IRQ handler and stm32_adc_trigger_handler runs in the IRQ thread to push out the buffer along with the timestamp. For this to work, the driver needs to register an IIO_TIMESTAMP channel. Do this. For DMA, it's not as easy, because we don't push the buffers out of stm32_adc_trigger, but out of stm32_adc_dma_buffer_done, which runs in a tasklet scheduled after a DMA completion. Preferably, the DMA controller would copy us the timestamp into that buffer as well. Until this is implemented, restrict timestamping support to only PIO. For low-frequency sampling, PIO is probably good enough. Cc: Holger Assmann <has@pengutronix.de> Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> --- v1 -> v2: - Added comment about timestamping being PIO only (Fabrice) - Added missing DMA resource clean up in error path (Fabrice) - Added Fabrice's Acked-by --- drivers/iio/adc/stm32-adc.c | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index c067c994dae2..885bb514503c 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1718,7 +1718,7 @@ static void stm32_adc_chan_init_one(struct iio_dev *indio_dev, } } -static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) +static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping) { struct device_node *node = indio_dev->dev.of_node; struct stm32_adc *adc = iio_priv(indio_dev); @@ -1766,6 +1766,9 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) return -EINVAL; } + if (timestamping) + num_channels++; + channels = devm_kcalloc(&indio_dev->dev, num_channels, sizeof(struct iio_chan_spec), GFP_KERNEL); if (!channels) @@ -1816,6 +1819,19 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) stm32_adc_smpr_init(adc, channels[i].channel, smp); } + if (timestamping) { + struct iio_chan_spec *timestamp = &channels[scan_index]; + + timestamp->type = IIO_TIMESTAMP; + timestamp->channel = -1; + timestamp->scan_index = scan_index; + timestamp->scan_type.sign = 's'; + timestamp->scan_type.realbits = 64; + timestamp->scan_type.storagebits = 64; + + scan_index++; + } + indio_dev->num_channels = scan_index; indio_dev->channels = channels; @@ -1875,6 +1891,7 @@ static int stm32_adc_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; irqreturn_t (*handler)(int irq, void *p) = NULL; struct stm32_adc *adc; + bool timestamping = false; int ret; if (!pdev->dev.of_node) @@ -1931,16 +1948,22 @@ static int stm32_adc_probe(struct platform_device *pdev) if (ret < 0) return ret; - ret = stm32_adc_chan_of_init(indio_dev); - if (ret < 0) - return ret; - ret = stm32_adc_dma_request(dev, indio_dev); if (ret < 0) return ret; - if (!adc->dma_chan) + if (!adc->dma_chan) { + /* For PIO mode only, iio_pollfunc_store_time stores a timestamp + * in the primary trigger IRQ handler and stm32_adc_trigger_handler + * runs in the IRQ thread to push out buffer along with timestamp. + */ handler = &stm32_adc_trigger_handler; + timestamping = true; + } + + ret = stm32_adc_chan_of_init(indio_dev, timestamping); + if (ret < 0) + goto err_dma_disable; ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, handler, -- 2.30.0
WARNING: multiple messages have this Message-ID (diff)
From: Ahmad Fatoum <a.fatoum@pengutronix.de> To: Jonathan Cameron <jic23@kernel.org>, Lars-Peter Clausen <lars@metafoo.de>, Peter Meerwald-Stadler <pmeerw@pmeerw.net>, Maxime Coquelin <mcoquelin.stm32@gmail.com>, Alexandre Torgue <alexandre.torgue@st.com> Cc: Ahmad Fatoum <a.fatoum@pengutronix.de>, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Fabrice Gasnier <fabrice.gasnier@foss.st.com>, kernel@pengutronix.de, Holger Assmann <has@pengutronix.de>, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2] iio: adc: stm32-adc: enable timestamping for non-DMA usage Date: Fri, 22 Jan 2021 12:33:55 +0100 [thread overview] Message-ID: <20210122113355.32384-1-a.fatoum@pengutronix.de> (raw) For non-DMA usage, we have an easy way to associate a timestamp with a sample: iio_pollfunc_store_time stores a timestamp in the primary trigger IRQ handler and stm32_adc_trigger_handler runs in the IRQ thread to push out the buffer along with the timestamp. For this to work, the driver needs to register an IIO_TIMESTAMP channel. Do this. For DMA, it's not as easy, because we don't push the buffers out of stm32_adc_trigger, but out of stm32_adc_dma_buffer_done, which runs in a tasklet scheduled after a DMA completion. Preferably, the DMA controller would copy us the timestamp into that buffer as well. Until this is implemented, restrict timestamping support to only PIO. For low-frequency sampling, PIO is probably good enough. Cc: Holger Assmann <has@pengutronix.de> Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> --- v1 -> v2: - Added comment about timestamping being PIO only (Fabrice) - Added missing DMA resource clean up in error path (Fabrice) - Added Fabrice's Acked-by --- drivers/iio/adc/stm32-adc.c | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index c067c994dae2..885bb514503c 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1718,7 +1718,7 @@ static void stm32_adc_chan_init_one(struct iio_dev *indio_dev, } } -static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) +static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping) { struct device_node *node = indio_dev->dev.of_node; struct stm32_adc *adc = iio_priv(indio_dev); @@ -1766,6 +1766,9 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) return -EINVAL; } + if (timestamping) + num_channels++; + channels = devm_kcalloc(&indio_dev->dev, num_channels, sizeof(struct iio_chan_spec), GFP_KERNEL); if (!channels) @@ -1816,6 +1819,19 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) stm32_adc_smpr_init(adc, channels[i].channel, smp); } + if (timestamping) { + struct iio_chan_spec *timestamp = &channels[scan_index]; + + timestamp->type = IIO_TIMESTAMP; + timestamp->channel = -1; + timestamp->scan_index = scan_index; + timestamp->scan_type.sign = 's'; + timestamp->scan_type.realbits = 64; + timestamp->scan_type.storagebits = 64; + + scan_index++; + } + indio_dev->num_channels = scan_index; indio_dev->channels = channels; @@ -1875,6 +1891,7 @@ static int stm32_adc_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; irqreturn_t (*handler)(int irq, void *p) = NULL; struct stm32_adc *adc; + bool timestamping = false; int ret; if (!pdev->dev.of_node) @@ -1931,16 +1948,22 @@ static int stm32_adc_probe(struct platform_device *pdev) if (ret < 0) return ret; - ret = stm32_adc_chan_of_init(indio_dev); - if (ret < 0) - return ret; - ret = stm32_adc_dma_request(dev, indio_dev); if (ret < 0) return ret; - if (!adc->dma_chan) + if (!adc->dma_chan) { + /* For PIO mode only, iio_pollfunc_store_time stores a timestamp + * in the primary trigger IRQ handler and stm32_adc_trigger_handler + * runs in the IRQ thread to push out buffer along with timestamp. + */ handler = &stm32_adc_trigger_handler; + timestamping = true; + } + + ret = stm32_adc_chan_of_init(indio_dev, timestamping); + if (ret < 0) + goto err_dma_disable; ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, handler, -- 2.30.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-01-22 11:37 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-22 11:33 Ahmad Fatoum [this message] 2021-01-22 11:33 ` [PATCH v2] iio: adc: stm32-adc: enable timestamping for non-DMA usage Ahmad Fatoum 2021-01-24 15:22 ` Jonathan Cameron 2021-01-24 15:22 ` Jonathan Cameron 2021-01-25 11:21 ` Ahmad Fatoum 2021-01-25 11:21 ` Ahmad Fatoum 2021-01-31 10:46 ` Jonathan Cameron 2021-01-31 10:46 ` Jonathan Cameron
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