| Message ID | 20210121180228.30621-1-a.fatoum@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: adc: stm32-adc: enable timestamping for non-DMA usage | expand |
On 1/21/21 7:02 PM, Ahmad Fatoum wrote: > 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> > Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> > --- > drivers/iio/adc/stm32-adc.c | 31 +++++++++++++++++++++++++------ > 1 file changed, 25 insertions(+), 6 deletions(-) > > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c > index c067c994dae2..91d9483e1f5f 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 +1948,18 @@ 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) { > handler = &stm32_adc_trigger_handler; Hi Ahmad, Just suggesting: maybe add a quick comment to indicate that timestamping is supported in PIO mode (only), as DMA doesn't fill it into the buffer (well described in the commit message). > + timestamping = true; > + } > + > + ret = stm32_adc_chan_of_init(indio_dev, timestamping); > + if (ret < 0) > + return ret; DMA resources need to be freed, instead of returning directly here, in case of error: goto err_dma_disable; With that fixed, you can add my : Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Thanks, Fabrice > > ret = iio_triggered_buffer_setup(indio_dev, > &iio_pollfunc_store_time, handler,
Hi, On 22.01.21 11:23, Fabrice Gasnier wrote: > On 1/21/21 7:02 PM, Ahmad Fatoum wrote: >> 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> >> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> >> --- >> drivers/iio/adc/stm32-adc.c | 31 +++++++++++++++++++++++++------ >> 1 file changed, 25 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c >> index c067c994dae2..91d9483e1f5f 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 +1948,18 @@ 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) { >> handler = &stm32_adc_trigger_handler; > > Hi Ahmad, > > Just suggesting: maybe add a quick comment to indicate that timestamping > is supported in PIO mode (only), as DMA doesn't fill it into the buffer > (well described in the commit message). Will do. > >> + timestamping = true; >> + } >> + >> + ret = stm32_adc_chan_of_init(indio_dev, timestamping); >> + if (ret < 0) >> + return ret; > > > DMA resources need to be freed, instead of returning directly here, in > case of error: > > goto err_dma_disable; Ouch, thanks for spotting. Will respin. > > With that fixed, you can add my : > > Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Thanks, Ahmad > > Thanks, > > Fabrice > > >> >> ret = iio_triggered_buffer_setup(indio_dev, >> &iio_pollfunc_store_time, handler, >
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index c067c994dae2..91d9483e1f5f 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 +1948,18 @@ 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) { handler = &stm32_adc_trigger_handler; + timestamping = true; + } + + ret = stm32_adc_chan_of_init(indio_dev, timestamping); + if (ret < 0) + return ret; ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, handler,
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> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> --- drivers/iio/adc/stm32-adc.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-)