[PATCH v3 0/3] iio: imu: adis: Use spi cs inactive delay

[PATCH v3 0/3] iio: imu: adis: Use spi cs inactive delay

[Ramona Gradinariu]

A delay is needed each time the chip selected becomes inactive,
even after burst data readings are performed.
Currently, there is no delay added after a burst reading
and in case a new SPI transfer is performed before
the needed delay, the adis device becomes unresponsive until
reset.

This commit is adding the needed delay directly to the spi driver,
using the cs_inactive parameter, in case it is not set and is
removing the additional chip select change delay present in adis
APIs to remove the double delay.

Ramona Gradinariu (3):
  iio: imu: adis: Use spi cs inactive delay
  dt-bindings: adis16475: Add 'spi-cs-inactive-delay-ns' property
  dt-bindings: adis16460: Add 'spi-cs-inactive-delay-ns' property

 .../bindings/iio/imu/adi,adis16460.yaml        |  4 ++++
 .../bindings/iio/imu/adi,adis16475.yaml        |  4 ++++
 drivers/iio/imu/adis.c                         | 18 ++++++------------
 3 files changed, 14 insertions(+), 12 deletions(-)

--
2.34.1

[PATCH v3 1/3] iio: imu: adis: Use spi cs inactive delay

[Ramona Gradinariu]

A delay is needed each time the chip selected becomes inactive,
even after burst data readings are performed.
Currently, there is no delay added after a burst reading
and in case a new SPI transfer is performed before
the needed delay, the adis device becomes unresponsive until
reset.

This commit is adding the needed delay directly to the spi driver,
using the cs_inactive parameter, in case it is not set and is
removing the additional chip select change delay present in adis
APIs to remove the double delay.

Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
---
 drivers/iio/imu/adis.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index bc40240b29e2..495caf4ce87a 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -44,8 +44,6 @@ int __adis_write_reg(struct adis *adis, unsigned int reg, unsigned int value,
 			.cs_change = 1,
 			.delay.value = adis->data->write_delay,
 			.delay.unit = SPI_DELAY_UNIT_USECS,
-			.cs_change_delay.value = adis->data->cs_change_delay,
-			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 2,
 			.bits_per_word = 8,
@@ -53,8 +51,6 @@ int __adis_write_reg(struct adis *adis, unsigned int reg, unsigned int value,
 			.cs_change = 1,
 			.delay.value = adis->data->write_delay,
 			.delay.unit = SPI_DELAY_UNIT_USECS,
-			.cs_change_delay.value = adis->data->cs_change_delay,
-			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 4,
 			.bits_per_word = 8,
@@ -62,8 +58,6 @@ int __adis_write_reg(struct adis *adis, unsigned int reg, unsigned int value,
 			.cs_change = 1,
 			.delay.value = adis->data->write_delay,
 			.delay.unit = SPI_DELAY_UNIT_USECS,
-			.cs_change_delay.value = adis->data->cs_change_delay,
-			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 6,
 			.bits_per_word = 8,
@@ -144,8 +138,6 @@ int __adis_read_reg(struct adis *adis, unsigned int reg, unsigned int *val,
 			.cs_change = 1,
 			.delay.value = adis->data->write_delay,
 			.delay.unit = SPI_DELAY_UNIT_USECS,
-			.cs_change_delay.value = adis->data->cs_change_delay,
-			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 2,
 			.bits_per_word = 8,
@@ -153,8 +145,6 @@ int __adis_read_reg(struct adis *adis, unsigned int reg, unsigned int *val,
 			.cs_change = 1,
 			.delay.value = adis->data->read_delay,
 			.delay.unit = SPI_DELAY_UNIT_USECS,
-			.cs_change_delay.value = adis->data->cs_change_delay,
-			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.tx_buf = adis->tx + 4,
 			.rx_buf = adis->rx,
@@ -163,8 +153,6 @@ int __adis_read_reg(struct adis *adis, unsigned int reg, unsigned int *val,
 			.cs_change = 1,
 			.delay.value = adis->data->read_delay,
 			.delay.unit = SPI_DELAY_UNIT_USECS,
-			.cs_change_delay.value = adis->data->cs_change_delay,
-			.cs_change_delay.unit = SPI_DELAY_UNIT_USECS,
 		}, {
 			.rx_buf = adis->rx + 2,
 			.bits_per_word = 8,
@@ -524,6 +512,12 @@ int adis_init(struct adis *adis, struct iio_dev *indio_dev,
 	}
 
 	mutex_init(&adis->state_lock);
+
+	if (!spi->cs_inactive.value) {
+		spi->cs_inactive.value = data->cs_change_delay;
+		spi->cs_inactive.unit = SPI_DELAY_UNIT_USECS;
+	}
+
 	adis->spi = spi;
 	adis->data = data;
 	iio_device_set_drvdata(indio_dev, adis);
-- 
2.34.1

[PATCH v3 2/3] dt-bindings: adis16475: Add 'spi-cs-inactive-delay-ns' property

[Ramona Gradinariu]

The devices supported by adis16475 driver require a stall period
between SPI transactions (during which the chip select is
inactive), with a minimum value equal to 16 microseconds, thus
adding 'spi-cs-inactive-delay-ns' property, which should indicate
the stall time between consecutive SPI transactions.
The specified minimum time may not be sufficient for all
configurations.

Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
changes in v3:
 - removed description
 - updated commit message
 Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml b/Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
index c73533c54588..9b7ad609f7db 100644
--- a/Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
+++ b/Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
@@ -47,6 +47,10 @@ properties:
   spi-max-frequency:
     maximum: 2000000

+  spi-cs-inactive-delay-ns:
+    minimum: 16000
+    default: 16000
+
   interrupts:
     maxItems: 1

--
2.34.1

[PATCH v3 3/3] dt-bindings: adis16460: Add 'spi-cs-inactive-delay-ns' property

[Ramona Gradinariu]

The adis16460 device requires a stall time between SPI
transactions (during which the chip select is inactive),
with a minimum value equal to 16 microseconds.
This commit adds 'spi-cs-inactive-delay-ns' property, which should
indicate the stall time between consecutive SPI transactions.
The specified minimum time may not be sufficient for all
configurations.

Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
changes in v3:
 - removed description
 - updated commit message
 Documentation/devicetree/bindings/iio/imu/adi,adis16460.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/imu/adi,adis16460.yaml b/Documentation/devicetree/bindings/iio/imu/adi,adis16460.yaml
index 4e43c80e5119..4cacc9948726 100644
--- a/Documentation/devicetree/bindings/iio/imu/adi,adis16460.yaml
+++ b/Documentation/devicetree/bindings/iio/imu/adi,adis16460.yaml
@@ -25,6 +25,10 @@ properties:

   spi-cpol: true

+  spi-cs-inactive-delay-ns:
+    minimum: 16000
+    default: 16000
+
   interrupts:
     maxItems: 1

--
2.34.1

Re: [PATCH v3 0/3] iio: imu: adis: Use spi cs inactive delay

[Jonathan Cameron]

On Fri, 27 Oct 2023 17:03:55 +0300
Ramona Gradinariu <ramona.gradinariu@analog.com> wrote:

> A delay is needed each time the chip selected becomes inactive,
> even after burst data readings are performed.
> Currently, there is no delay added after a burst reading
> and in case a new SPI transfer is performed before
> the needed delay, the adis device becomes unresponsive until
> reset.
> 
> This commit is adding the needed delay directly to the spi driver,
> using the cs_inactive parameter, in case it is not set and is
> removing the additional chip select change delay present in adis
> APIs to remove the double delay.

Series applied.

I'm a bit confused though as this one is turning up in patchwork.
Meh, maybe a delay and it will show up soon.

Jonathan

> 
> Ramona Gradinariu (3):
>   iio: imu: adis: Use spi cs inactive delay
>   dt-bindings: adis16475: Add 'spi-cs-inactive-delay-ns' property
>   dt-bindings: adis16460: Add 'spi-cs-inactive-delay-ns' property
> 
>  .../bindings/iio/imu/adi,adis16460.yaml        |  4 ++++
>  .../bindings/iio/imu/adi,adis16475.yaml        |  4 ++++
>  drivers/iio/imu/adis.c                         | 18 ++++++------------
>  3 files changed, 14 insertions(+), 12 deletions(-)
> 
> --
> 2.34.1
>