* [PATCH v3] iio: adc: stm32-adc: enable timestamping for non-DMA usage
@ 2021-01-25 11:21 ` Ahmad Fatoum
0 siblings, 0 replies; 6+ messages in thread
From: Ahmad Fatoum @ 2021-01-25 11:21 UTC (permalink / raw)
To: Jonathan Cameron, Lars-Peter Clausen, Peter Meerwald-Stadler,
Maxime Coquelin, Alexandre Torgue
Cc: kernel, Holger Assmann, Fabrice Gasnier, Ahmad Fatoum, linux-iio,
linux-stm32, linux-arm-kernel, linux-kernel
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>
---
v2 -> v3:
- explicitly specify alignment (Jonathan)
- increase buffer size to hold additional timestamp
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 | 39 +++++++++++++++++++++++++++++--------
1 file changed, 31 insertions(+), 8 deletions(-)
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index c067c994dae2..ab2f440d7afb 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -177,7 +177,7 @@ struct stm32_adc_cfg {
* @offset: ADC instance register offset in ADC block
* @cfg: compatible configuration data
* @completion: end of single conversion completion
- * @buffer: data buffer
+ * @buffer: data buffer + 8 bytes for timestamp if enabled
* @clk: clock for this adc instance
* @irq: interrupt for this adc instance
* @lock: spinlock
@@ -200,7 +200,7 @@ struct stm32_adc {
u32 offset;
const struct stm32_adc_cfg *cfg;
struct completion completion;
- u16 buffer[STM32_ADC_MAX_SQ];
+ u16 buffer[STM32_ADC_MAX_SQ + 8] __aligned(8);
struct clk *clk;
int irq;
spinlock_t lock; /* interrupt lock */
@@ -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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v3] iio: adc: stm32-adc: enable timestamping for non-DMA usage
@ 2021-01-25 11:21 ` Ahmad Fatoum
0 siblings, 0 replies; 6+ messages in thread
From: Ahmad Fatoum @ 2021-01-25 11:21 UTC (permalink / raw)
To: Jonathan Cameron, Lars-Peter Clausen, Peter Meerwald-Stadler,
Maxime Coquelin, Alexandre Torgue
Cc: Ahmad Fatoum, linux-iio, linux-kernel, Fabrice Gasnier, kernel,
Holger Assmann, linux-stm32, linux-arm-kernel
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>
---
v2 -> v3:
- explicitly specify alignment (Jonathan)
- increase buffer size to hold additional timestamp
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 | 39 +++++++++++++++++++++++++++++--------
1 file changed, 31 insertions(+), 8 deletions(-)
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index c067c994dae2..ab2f440d7afb 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -177,7 +177,7 @@ struct stm32_adc_cfg {
* @offset: ADC instance register offset in ADC block
* @cfg: compatible configuration data
* @completion: end of single conversion completion
- * @buffer: data buffer
+ * @buffer: data buffer + 8 bytes for timestamp if enabled
* @clk: clock for this adc instance
* @irq: interrupt for this adc instance
* @lock: spinlock
@@ -200,7 +200,7 @@ struct stm32_adc {
u32 offset;
const struct stm32_adc_cfg *cfg;
struct completion completion;
- u16 buffer[STM32_ADC_MAX_SQ];
+ u16 buffer[STM32_ADC_MAX_SQ + 8] __aligned(8);
struct clk *clk;
int irq;
spinlock_t lock; /* interrupt lock */
@@ -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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v3] iio: adc: stm32-adc: enable timestamping for non-DMA usage
2021-01-25 11:21 ` Ahmad Fatoum
@ 2021-01-25 11:49 ` Marc Kleine-Budde
-1 siblings, 0 replies; 6+ messages in thread
From: Marc Kleine-Budde @ 2021-01-25 11:49 UTC (permalink / raw)
To: Ahmad Fatoum, Jonathan Cameron, Lars-Peter Clausen,
Peter Meerwald-Stadler, Maxime Coquelin, Alexandre Torgue
Cc: linux-iio, linux-kernel, Fabrice Gasnier, kernel, Holger Assmann,
linux-stm32, linux-arm-kernel
[-- Attachment #1.1: Type: text/plain, Size: 2672 bytes --]
On 1/25/21 12:21 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>
> Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v2 -> v3:
> - explicitly specify alignment (Jonathan)
> - increase buffer size to hold additional timestamp
> 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 | 39 +++++++++++++++++++++++++++++--------
> 1 file changed, 31 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index c067c994dae2..ab2f440d7afb 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -177,7 +177,7 @@ struct stm32_adc_cfg {
> * @offset: ADC instance register offset in ADC block
> * @cfg: compatible configuration data
> * @completion: end of single conversion completion
> - * @buffer: data buffer
> + * @buffer: data buffer + 8 bytes for timestamp if enabled
^
> * @clk: clock for this adc instance
> * @irq: interrupt for this adc instance
> * @lock: spinlock
> @@ -200,7 +200,7 @@ struct stm32_adc {
> u32 offset;
> const struct stm32_adc_cfg *cfg;
> struct completion completion;
> - u16 buffer[STM32_ADC_MAX_SQ];
> + u16 buffer[STM32_ADC_MAX_SQ + 8] __aligned(8);
^^ ^
How does that fit together?
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
[-- Attachment #2: OpenPGP digital signature --]
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] iio: adc: stm32-adc: enable timestamping for non-DMA usage
@ 2021-01-25 11:49 ` Marc Kleine-Budde
0 siblings, 0 replies; 6+ messages in thread
From: Marc Kleine-Budde @ 2021-01-25 11:49 UTC (permalink / raw)
To: Ahmad Fatoum, Jonathan Cameron, Lars-Peter Clausen,
Peter Meerwald-Stadler, Maxime Coquelin, Alexandre Torgue
Cc: Holger Assmann, linux-iio, linux-kernel, Fabrice Gasnier, kernel,
linux-stm32, linux-arm-kernel
[-- Attachment #1.1.1: Type: text/plain, Size: 2672 bytes --]
On 1/25/21 12:21 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>
> Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v2 -> v3:
> - explicitly specify alignment (Jonathan)
> - increase buffer size to hold additional timestamp
> 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 | 39 +++++++++++++++++++++++++++++--------
> 1 file changed, 31 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index c067c994dae2..ab2f440d7afb 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -177,7 +177,7 @@ struct stm32_adc_cfg {
> * @offset: ADC instance register offset in ADC block
> * @cfg: compatible configuration data
> * @completion: end of single conversion completion
> - * @buffer: data buffer
> + * @buffer: data buffer + 8 bytes for timestamp if enabled
^
> * @clk: clock for this adc instance
> * @irq: interrupt for this adc instance
> * @lock: spinlock
> @@ -200,7 +200,7 @@ struct stm32_adc {
> u32 offset;
> const struct stm32_adc_cfg *cfg;
> struct completion completion;
> - u16 buffer[STM32_ADC_MAX_SQ];
> + u16 buffer[STM32_ADC_MAX_SQ + 8] __aligned(8);
^^ ^
How does that fit together?
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
[-- Attachment #1.2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
[-- Attachment #2: Type: text/plain, Size: 176 bytes --]
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] iio: adc: stm32-adc: enable timestamping for non-DMA usage
2021-01-25 11:49 ` Marc Kleine-Budde
@ 2021-01-25 11:57 ` Ahmad Fatoum
-1 siblings, 0 replies; 6+ messages in thread
From: Ahmad Fatoum @ 2021-01-25 11:57 UTC (permalink / raw)
To: Marc Kleine-Budde, Jonathan Cameron, Lars-Peter Clausen,
Peter Meerwald-Stadler, Maxime Coquelin, Alexandre Torgue
Cc: linux-iio, linux-kernel, Fabrice Gasnier, kernel, Holger Assmann,
linux-stm32, linux-arm-kernel
On 25.01.21 12:49, Marc Kleine-Budde wrote:
> On 1/25/21 12:21 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>
>> Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> ---
>> v2 -> v3:
>> - explicitly specify alignment (Jonathan)
>> - increase buffer size to hold additional timestamp
>> 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 | 39 +++++++++++++++++++++++++++++--------
>> 1 file changed, 31 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
>> index c067c994dae2..ab2f440d7afb 100644
>> --- a/drivers/iio/adc/stm32-adc.c
>> +++ b/drivers/iio/adc/stm32-adc.c
>> @@ -177,7 +177,7 @@ struct stm32_adc_cfg {
>> * @offset: ADC instance register offset in ADC block
>> * @cfg: compatible configuration data
>> * @completion: end of single conversion completion
>> - * @buffer: data buffer
>> + * @buffer: data buffer + 8 bytes for timestamp if enabled
> ^
>> * @clk: clock for this adc instance
>> * @irq: interrupt for this adc instance
>> * @lock: spinlock
>> @@ -200,7 +200,7 @@ struct stm32_adc {
>> u32 offset;
>> const struct stm32_adc_cfg *cfg;
>> struct completion completion;
>> - u16 buffer[STM32_ADC_MAX_SQ];
>> + u16 buffer[STM32_ADC_MAX_SQ + 8] __aligned(8);
> ^^ ^
>
> How does that fit together?
Ah indeed, that's a little longer than needed.
Thanks for catching.
>
> Marc
>
>
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] iio: adc: stm32-adc: enable timestamping for non-DMA usage
@ 2021-01-25 11:57 ` Ahmad Fatoum
0 siblings, 0 replies; 6+ messages in thread
From: Ahmad Fatoum @ 2021-01-25 11:57 UTC (permalink / raw)
To: Marc Kleine-Budde, Jonathan Cameron, Lars-Peter Clausen,
Peter Meerwald-Stadler, Maxime Coquelin, Alexandre Torgue
Cc: Holger Assmann, linux-iio, linux-kernel, Fabrice Gasnier, kernel,
linux-stm32, linux-arm-kernel
On 25.01.21 12:49, Marc Kleine-Budde wrote:
> On 1/25/21 12:21 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>
>> Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> ---
>> v2 -> v3:
>> - explicitly specify alignment (Jonathan)
>> - increase buffer size to hold additional timestamp
>> 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 | 39 +++++++++++++++++++++++++++++--------
>> 1 file changed, 31 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
>> index c067c994dae2..ab2f440d7afb 100644
>> --- a/drivers/iio/adc/stm32-adc.c
>> +++ b/drivers/iio/adc/stm32-adc.c
>> @@ -177,7 +177,7 @@ struct stm32_adc_cfg {
>> * @offset: ADC instance register offset in ADC block
>> * @cfg: compatible configuration data
>> * @completion: end of single conversion completion
>> - * @buffer: data buffer
>> + * @buffer: data buffer + 8 bytes for timestamp if enabled
> ^
>> * @clk: clock for this adc instance
>> * @irq: interrupt for this adc instance
>> * @lock: spinlock
>> @@ -200,7 +200,7 @@ struct stm32_adc {
>> u32 offset;
>> const struct stm32_adc_cfg *cfg;
>> struct completion completion;
>> - u16 buffer[STM32_ADC_MAX_SQ];
>> + u16 buffer[STM32_ADC_MAX_SQ + 8] __aligned(8);
> ^^ ^
>
> How does that fit together?
Ah indeed, that's a little longer than needed.
Thanks for catching.
>
> Marc
>
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-01-26 19:16 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-25 11:21 [PATCH v3] iio: adc: stm32-adc: enable timestamping for non-DMA usage Ahmad Fatoum
2021-01-25 11:21 ` Ahmad Fatoum
2021-01-25 11:49 ` Marc Kleine-Budde
2021-01-25 11:49 ` Marc Kleine-Budde
2021-01-25 11:57 ` Ahmad Fatoum
2021-01-25 11:57 ` Ahmad Fatoum
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