While working on another series[1] I ran into issues where my SPI
controller would fail to handle 14-bit and 16-bit SPI messages. This
addresses that issue and adds support for selecting a different voltage
reference source from the devicetree.
This is base on a series[2] that seems to not have made it all the way,
and was tested on an ad7689.
[1] https://patchwork.kernel.org/project/linux-iio/list/?series=511545
[2] https://patchwork.kernel.org/project/linux-iio/list/?series=116971&state=%2A&archive=both
Thanks for your time,
Liam
Liam Beguin (4):
iio: adc: ad7949: define and use bitfield names
iio: adc: ad7949: fix spi messages on non 14-bit controllers
iio: adc: ad7949: add support for internal vref
dt-bindings: iio: adc: ad7949: add adi,reference-source
.../bindings/iio/adc/adi,ad7949.yaml | 22 ++
drivers/iio/adc/ad7949.c | 191 +++++++++++++++---
2 files changed, 181 insertions(+), 32 deletions(-)
base-commit: 6cbb3aa0f9d5d23221df787cf36f74d3866fdb78
--
2.30.1.489.g328c10930387
From: Liam Beguin <[email protected]>
Add support for selecting a custom reference voltage from the
devicetree. If an external source is used, a vref regulator should be
defined in the devicetree.
Signed-off-by: Liam Beguin <[email protected]>
---
drivers/iio/adc/ad7949.c | 84 +++++++++++++++++++++++++++++++++-------
1 file changed, 69 insertions(+), 15 deletions(-)
diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
index bbc6b56330a3..3c1293922d2e 100644
--- a/drivers/iio/adc/ad7949.c
+++ b/drivers/iio/adc/ad7949.c
@@ -31,6 +31,7 @@
#define AD7949_CFG_VAL_BW_FULL 1
#define AD7949_CFG_VAL_BW_QUARTER 0
#define AD7949_CFG_BIT_REF GENMASK(5, 3)
+#define AD7949_CFG_VAL_REF_EXTERNAL BIT(1)
#define AD7949_CFG_BIT_SEQ GENMASK(2, 1)
#define AD7949_CFG_BIT_RBN BIT(0)
@@ -40,6 +41,33 @@ enum {
ID_AD7689,
};
+/**
+ * enum ad7949_ref - Reference selection
+ *
+ * AD7949_REF_INT_2500: Internal reference and temperature sensor enabled.
+ * Vref=2.5V, buffered output
+ * AD7949_REF_INT_4096: Internal reference and temperature sensor enabled.
+ * Vref=4.096V, buffered output
+ * AD7949_REF_EXT_TEMP: Use external reference, temperature sensor enabled.
+ * Internal buffer disabled
+ * AD7949_REF_EXT_TEMP_BUF: Use external reference, internal buffer and
+ * temperature sensor enabled.
+ * AD7949_REF_RSRV_4: Do not use
+ * AD7949_REF_RSRV_5: Do not use
+ * AD7949_REF_EXT: Use external reference, internal buffer and
+ * temperature sensor disabled.
+ * AD7949_REF_EXT_BUF: Use external reference, internal buffer enabled.
+ * Internal reference and temperature sensor disabled.
+ */
+enum ad7949_ref {
+ AD7949_REF_INT_2500 = 0,
+ AD7949_REF_INT_4096,
+ AD7949_REF_EXT_TEMP,
+ AD7949_REF_EXT_TEMP_BUF,
+ AD7949_REF_EXT = 6,
+ AD7949_REF_EXT_BUF,
+};
+
struct ad7949_adc_spec {
u8 num_channels;
u8 resolution;
@@ -55,6 +83,7 @@ static const struct ad7949_adc_spec ad7949_adc_spec[] = {
* struct ad7949_adc_chip - AD ADC chip
* @lock: protects write sequences
* @vref: regulator generating Vref
+ * @refsel: reference selection
* @indio_dev: reference to iio structure
* @spi: reference to spi structure
* @resolution: resolution of the chip
@@ -66,6 +95,7 @@ static const struct ad7949_adc_spec ad7949_adc_spec[] = {
struct ad7949_adc_chip {
struct mutex lock;
struct regulator *vref;
+ enum ad7949_ref refsel;
struct iio_dev *indio_dev;
struct spi_device *spi;
u8 resolution;
@@ -241,12 +271,28 @@ static int ad7949_spi_read_raw(struct iio_dev *indio_dev,
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
- ret = regulator_get_voltage(ad7949_adc->vref);
- if (ret < 0)
- return ret;
+ switch (ad7949_adc->refsel) {
+ case AD7949_REF_INT_2500:
+ *val = 2500;
+ break;
+ case AD7949_REF_INT_4096:
+ *val = 4096;
+ break;
+ case AD7949_REF_EXT_TEMP:
+ case AD7949_REF_EXT_TEMP_BUF:
+ case AD7949_REF_EXT:
+ case AD7949_REF_EXT_BUF:
+ ret = regulator_get_voltage(ad7949_adc->vref);
+ if (ret < 0)
+ return ret;
+
+ /* convert value back to mV */
+ *val = ret / 1000;
+ break;
+ }
- *val = ret / 5000;
- return IIO_VAL_INT;
+ *val2 = (1 << ad7949_adc->resolution) - 1;
+ return IIO_VAL_FRACTIONAL;
}
return -EINVAL;
@@ -285,7 +331,7 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc)
FIELD_PREP(AD7949_CFG_BIT_INCC, AD7949_CFG_VAL_INCC_UNIPOLAR_GND) |
FIELD_PREP(AD7949_CFG_BIT_INX, ad7949_adc->current_channel) |
FIELD_PREP(AD7949_CFG_BIT_BW, AD7949_CFG_VAL_BW_FULL) |
- FIELD_PREP(AD7949_CFG_BIT_REF, AD7949_REF_EXT_BUF) |
+ FIELD_PREP(AD7949_CFG_BIT_REF, ad7949_adc->refsel) |
FIELD_PREP(AD7949_CFG_BIT_SEQ, 0x0) |
FIELD_PREP(AD7949_CFG_BIT_RBN, 1);
@@ -304,6 +350,7 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc)
static int ad7949_spi_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
+ struct device_node *np = dev->of_node;
const struct ad7949_adc_spec *spec;
struct ad7949_adc_chip *ad7949_adc;
struct iio_dev *indio_dev;
@@ -315,6 +362,7 @@ static int ad7949_spi_probe(struct spi_device *spi)
return -ENOMEM;
}
+ indio_dev->dev.of_node = np;
indio_dev->info = &ad7949_spi_info;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
@@ -330,16 +378,22 @@ static int ad7949_spi_probe(struct spi_device *spi)
ad7949_adc->resolution = spec->resolution;
ad7949_set_bits_per_word(ad7949_adc);
- ad7949_adc->vref = devm_regulator_get(dev, "vref");
- if (IS_ERR(ad7949_adc->vref)) {
- dev_err(dev, "fail to request regulator\n");
- return PTR_ERR(ad7949_adc->vref);
- }
+ /* Set default devicetree parameters */
+ ad7949_adc->refsel = AD7949_REF_EXT_BUF;
+ of_property_read_u32(np, "adi,reference-select", &ad7949_adc->refsel);
- ret = regulator_enable(ad7949_adc->vref);
- if (ret < 0) {
- dev_err(dev, "fail to enable regulator\n");
- return ret;
+ if (ad7949_adc->refsel & AD7949_CFG_VAL_REF_EXTERNAL) {
+ ad7949_adc->vref = devm_regulator_get(dev, "vref");
+ if (IS_ERR(ad7949_adc->vref)) {
+ dev_err(dev, "fail to request regulator\n");
+ return PTR_ERR(ad7949_adc->vref);
+ }
+
+ ret = regulator_enable(ad7949_adc->vref);
+ if (ret < 0) {
+ dev_err(dev, "fail to enable regulator\n");
+ return ret;
+ }
}
mutex_init(&ad7949_adc->lock);
--
2.30.1.489.g328c10930387
From: Liam Beguin <[email protected]>
Add bindings documentation for the adi,reference-source property.
This property is required to properly configure the ADC sample request
based on which reference source should be used for the calculation.
Signed-off-by: Liam Beguin <[email protected]>
---
.../bindings/iio/adc/adi,ad7949.yaml | 22 +++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
index 9b56bd4d5510..3f4629281cc8 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
@@ -35,6 +35,28 @@ properties:
"#io-channel-cells":
const: 1
+ adi,reference-select:
+ allOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - enum: [0, 1, 2, 3, 6, 7]
+
+ default: 7
+ description: |
+ Select the reference voltage source to use when converting samples.
+ Acceptable values are:
+ - 0: Internal reference and temperature sensor enabled.
+ Vref=2.5V, buffered output
+ - 1: Internal reference and temperature sensor enabled.
+ Vref=4.096V, buffered output
+ - 2: Use external reference, temperature sensor enabled.
+ Internal buffer disabled
+ - 3: Use external reference, internal buffer and temperature sensor
+ enabled.
+ - 6: Use external reference, internal buffer and temperature sensor
+ disabled.
+ - 7: Use external reference, internal buffer enabled.
+ Internal reference and temperature sensor disabled.
+
required:
- compatible
- reg
--
2.30.1.489.g328c10930387
From: Liam Beguin <[email protected]>
This driver supports devices with 14-bit and 16-bit sample sizes.
This is not always handled properly by spi controllers and can fail. To
work around this limitation, pad samples to 16-bit and split the sample
into two 8-bit messages in the event that only 8-bit messages are
supported by the controller.
Signed-off-by: Liam Beguin <[email protected]>
---
drivers/iio/adc/ad7949.c | 67 ++++++++++++++++++++++++++++++++++------
1 file changed, 58 insertions(+), 9 deletions(-)
diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
index 93aacf4f680b..bbc6b56330a3 100644
--- a/drivers/iio/adc/ad7949.c
+++ b/drivers/iio/adc/ad7949.c
@@ -11,6 +11,7 @@
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
+#include <linux/bitfield.h>
#define AD7949_MASK_TOTAL GENMASK(13, 0)
#define AD7949_CFG_REG_SIZE_BITS 14
@@ -57,6 +58,7 @@ static const struct ad7949_adc_spec ad7949_adc_spec[] = {
* @indio_dev: reference to iio structure
* @spi: reference to spi structure
* @resolution: resolution of the chip
+ * @bits_per_word: number of bits per SPI word
* @cfg: copy of the configuration register
* @current_channel: current channel in use
* @buffer: buffer to send / receive data to / from device
@@ -67,28 +69,59 @@ struct ad7949_adc_chip {
struct iio_dev *indio_dev;
struct spi_device *spi;
u8 resolution;
+ u8 bits_per_word;
u16 cfg;
unsigned int current_channel;
- u16 buffer ____cacheline_aligned;
+ union {
+ __be16 buffer;
+ u8 buf8[2];
+ } ____cacheline_aligned;
};
+static void ad7949_set_bits_per_word(struct ad7949_adc_chip *ad7949_adc)
+{
+ u32 adc_mask = SPI_BPW_MASK(ad7949_adc->resolution);
+ u32 bpw = adc_mask & ad7949_adc->spi->controller->bits_per_word_mask;
+
+ if (bpw == adc_mask)
+ ad7949_adc->bits_per_word = ad7949_adc->resolution;
+ else if (bpw == SPI_BPW_MASK(16))
+ ad7949_adc->bits_per_word = 16;
+ else
+ ad7949_adc->bits_per_word = 8;
+}
+
static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc, u16 val,
u16 mask)
{
int ret;
- int bits_per_word = ad7949_adc->resolution;
- int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS;
struct spi_message msg;
struct spi_transfer tx[] = {
{
.tx_buf = &ad7949_adc->buffer,
.len = 2,
- .bits_per_word = bits_per_word,
+ .bits_per_word = ad7949_adc->bits_per_word,
},
};
+ ad7949_adc->buffer = 0;
ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask);
- ad7949_adc->buffer = ad7949_adc->cfg << shift;
+
+ switch (ad7949_adc->bits_per_word) {
+ case 16:
+ ad7949_adc->buffer = ad7949_adc->cfg << 2;
+ break;
+ case 14:
+ ad7949_adc->buffer = ad7949_adc->cfg;
+ break;
+ case 8:
+ /* Pack 14-bit value into 2 bytes, MSB first */
+ ad7949_adc->buf8[0] = FIELD_GET(GENMASK(13, 6), ad7949_adc->cfg);
+ ad7949_adc->buf8[1] = FIELD_GET(GENMASK(5, 0), ad7949_adc->cfg);
+ ad7949_adc->buf8[1] = ad7949_adc->buf8[1] << 2;
+ break;
+ }
+
spi_message_init_with_transfers(&msg, tx, 1);
ret = spi_sync(ad7949_adc->spi, &msg);
@@ -105,14 +138,12 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val,
{
int ret;
int i;
- int bits_per_word = ad7949_adc->resolution;
- int mask = GENMASK(ad7949_adc->resolution - 1, 0);
struct spi_message msg;
struct spi_transfer tx[] = {
{
.rx_buf = &ad7949_adc->buffer,
.len = 2,
- .bits_per_word = bits_per_word,
+ .bits_per_word = ad7949_adc->bits_per_word,
},
};
@@ -147,7 +178,24 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val,
ad7949_adc->current_channel = channel;
- *val = ad7949_adc->buffer & mask;
+ switch (ad7949_adc->bits_per_word) {
+ case 16:
+ *val = ad7949_adc->buffer;
+ /* Shift-out padding bits */
+ if (ad7949_adc->resolution == 14)
+ *val = *val >> 2;
+ break;
+ case 14:
+ *val = ad7949_adc->buffer & GENMASK(13, 0);
+ break;
+ case 8:
+ /* Convert byte array to u16, MSB first */
+ *val = (ad7949_adc->buf8[0] << 8) | ad7949_adc->buf8[1];
+ /* Shift-out padding bits */
+ if (ad7949_adc->resolution == 14)
+ *val = *val >> 2;
+ break;
+ }
return 0;
}
@@ -280,6 +328,7 @@ static int ad7949_spi_probe(struct spi_device *spi)
spec = &ad7949_adc_spec[spi_get_device_id(spi)->driver_data];
indio_dev->num_channels = spec->num_channels;
ad7949_adc->resolution = spec->resolution;
+ ad7949_set_bits_per_word(ad7949_adc);
ad7949_adc->vref = devm_regulator_get(dev, "vref");
if (IS_ERR(ad7949_adc->vref)) {
--
2.30.1.489.g328c10930387
Hi Liam,
The series looks good. Just some minor comments from my side...
Thanks!
- Nuno S?
> From: Liam Beguin <[email protected]>
> Sent: Friday, July 9, 2021 1:56 AM
> To: [email protected]; [email protected]; Hennerich, Michael
> <[email protected]>; [email protected]; charles-
> [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: [PATCH v1 0/4] AD7949 Fixes
>
> [External]
>
> While working on another series[1] I ran into issues where my SPI
> controller would fail to handle 14-bit and 16-bit SPI messages. This
> addresses that issue and adds support for selecting a different voltage
> reference source from the devicetree.
>
> This is base on a series[2] that seems to not have made it all the way,
> and was tested on an ad7689.
>
> [1]
> https://urldefense.com/v3/__https://patchwork.kernel.org/project/li
> nux-iio/list/?series=511545__;!!A3Ni8CS0y2Y!rF7O-WxC7HZM4hv_o-
> zYPtVCmZlDoASzPvamwwQkH9llVS8J-GpfQltvDBz7gQ$
> [2]
> https://urldefense.com/v3/__https://patchwork.kernel.org/project/li
> nux-
> iio/list/?series=116971&state=*2A&archive=both__;JQ!!A3Ni8CS0y2Y!
> rF7O-WxC7HZM4hv_o-zYPtVCmZlDoASzPvamwwQkH9llVS8J-GpfQluZ-
> w3LYA$
>
> Thanks for your time,
> Liam
>
> Liam Beguin (4):
> iio: adc: ad7949: define and use bitfield names
> iio: adc: ad7949: fix spi messages on non 14-bit controllers
> iio: adc: ad7949: add support for internal vref
> dt-bindings: iio: adc: ad7949: add adi,reference-source
>
> .../bindings/iio/adc/adi,ad7949.yaml | 22 ++
> drivers/iio/adc/ad7949.c | 191 +++++++++++++++---
> 2 files changed, 181 insertions(+), 32 deletions(-)
>
>
> base-commit: 6cbb3aa0f9d5d23221df787cf36f74d3866fdb78
> --
> 2.30.1.489.g328c10930387
> -----Original Message-----
> From: Liam Beguin <[email protected]>
> Sent: Friday, July 9, 2021 1:56 AM
> To: [email protected]; [email protected]; Hennerich, Michael
> <[email protected]>; [email protected]; charles-
> [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: [PATCH v1 4/4] dt-bindings: iio: adc: ad7949: add
> adi,reference-source
>
> [External]
>
> From: Liam Beguin <[email protected]>
>
> Add bindings documentation for the adi,reference-source property.
> This property is required to properly configure the ADC sample request
> based on which reference source should be used for the calculation.
>
> Signed-off-by: Liam Beguin <[email protected]>
> ---
> .../bindings/iio/adc/adi,ad7949.yaml | 22 +++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git
> a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> index 9b56bd4d5510..3f4629281cc8 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> @@ -35,6 +35,28 @@ properties:
> "#io-channel-cells":
> const: 1
>
> + adi,reference-select:
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - enum: [0, 1, 2, 3, 6, 7]
> +
> + default: 7
> + description: |
> + Select the reference voltage source to use when converting
> samples.
> + Acceptable values are:
> + - 0: Internal reference and temperature sensor enabled.
> + Vref=2.5V, buffered output
> + - 1: Internal reference and temperature sensor enabled.
> + Vref=4.096V, buffered output
> + - 2: Use external reference, temperature sensor enabled.
> + Internal buffer disabled
> + - 3: Use external reference, internal buffer and temperature
> sensor
> + enabled.
> + - 6: Use external reference, internal buffer and temperature
> sensor
> + disabled.
> + - 7: Use external reference, internal buffer enabled.
> + Internal reference and temperature sensor disabled.
I think typically the description comes first. I also don't think you
need the 'allOf'(not even sure if it will pass the binding check)...
Just have '$ref' and 'enum' on the same level.
- Nuno S?
> required:
> - compatible
> - reg
> --
> 2.30.1.489.g328c10930387
> -----Original Message-----
> From: Liam Beguin <[email protected]>
> Sent: Friday, July 9, 2021 1:56 AM
> To: [email protected]; [email protected]; Hennerich, Michael
> <[email protected]>; [email protected]; charles-
> [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: [PATCH v1 2/4] iio: adc: ad7949: fix spi messages on non 14-bit
> controllers
>
> [External]
>
> From: Liam Beguin <[email protected]>
>
> This driver supports devices with 14-bit and 16-bit sample sizes.
> This is not always handled properly by spi controllers and can fail. To
> work around this limitation, pad samples to 16-bit and split the sample
> into two 8-bit messages in the event that only 8-bit messages are
> supported by the controller.
>
> Signed-off-by: Liam Beguin <[email protected]>
> ---
> drivers/iio/adc/ad7949.c | 67
> ++++++++++++++++++++++++++++++++++------
> 1 file changed, 58 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
> index 93aacf4f680b..bbc6b56330a3 100644
> --- a/drivers/iio/adc/ad7949.c
> +++ b/drivers/iio/adc/ad7949.c
> @@ -11,6 +11,7 @@
> #include <linux/module.h>
> #include <linux/regulator/consumer.h>
> #include <linux/spi/spi.h>
> +#include <linux/bitfield.h>
>
> #define AD7949_MASK_TOTAL GENMASK(13, 0)
> #define AD7949_CFG_REG_SIZE_BITS 14
> @@ -57,6 +58,7 @@ static const struct ad7949_adc_spec
> ad7949_adc_spec[] = {
> * @indio_dev: reference to iio structure
> * @spi: reference to spi structure
> * @resolution: resolution of the chip
> + * @bits_per_word: number of bits per SPI word
> * @cfg: copy of the configuration register
> * @current_channel: current channel in use
> * @buffer: buffer to send / receive data to / from device
> @@ -67,28 +69,59 @@ struct ad7949_adc_chip {
> struct iio_dev *indio_dev;
> struct spi_device *spi;
> u8 resolution;
> + u8 bits_per_word;
> u16 cfg;
> unsigned int current_channel;
> - u16 buffer ____cacheline_aligned;
> + union {
> + __be16 buffer;
> + u8 buf8[2];
> + } ____cacheline_aligned;
> };
>
> +static void ad7949_set_bits_per_word(struct ad7949_adc_chip
> *ad7949_adc)
> +{
> + u32 adc_mask = SPI_BPW_MASK(ad7949_adc->resolution);
> + u32 bpw = adc_mask & ad7949_adc->spi->controller-
> >bits_per_word_mask;
> +
> + if (bpw == adc_mask)
> + ad7949_adc->bits_per_word = ad7949_adc-
> >resolution;
> + else if (bpw == SPI_BPW_MASK(16))
> + ad7949_adc->bits_per_word = 16;
> + else
> + ad7949_adc->bits_per_word = 8;
> +}
> +
> static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc,
> u16 val,
> u16 mask)
> {
> int ret;
> - int bits_per_word = ad7949_adc->resolution;
> - int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS;
> struct spi_message msg;
> struct spi_transfer tx[] = {
> {
> .tx_buf = &ad7949_adc->buffer,
> .len = 2,
> - .bits_per_word = bits_per_word,
> + .bits_per_word = ad7949_adc->bits_per_word,
> },
> };
>
> + ad7949_adc->buffer = 0;
> ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask);
> - ad7949_adc->buffer = ad7949_adc->cfg << shift;
> +
> + switch (ad7949_adc->bits_per_word) {
> + case 16:
> + ad7949_adc->buffer = ad7949_adc->cfg << 2;
> + break;
> + case 14:
> + ad7949_adc->buffer = ad7949_adc->cfg;
> + break;
> + case 8:
> + /* Pack 14-bit value into 2 bytes, MSB first */
> + ad7949_adc->buf8[0] = FIELD_GET(GENMASK(13, 6),
> ad7949_adc->cfg);
> + ad7949_adc->buf8[1] = FIELD_GET(GENMASK(5, 0),
> ad7949_adc->cfg);
> + ad7949_adc->buf8[1] = ad7949_adc->buf8[1] << 2;
> + break;
> + }
Honestly I didn't went through the driver but just a question... Are we
sure that 'ad7949_adc->resolution' will have something valid (8, 14, 16)?
A default statement is always a nice to have :).
> spi_message_init_with_transfers(&msg, tx, 1);
> ret = spi_sync(ad7949_adc->spi, &msg);
>
> @@ -105,14 +138,12 @@ static int ad7949_spi_read_channel(struct
> ad7949_adc_chip *ad7949_adc, int *val,
> {
> int ret;
> int i;
> - int bits_per_word = ad7949_adc->resolution;
> - int mask = GENMASK(ad7949_adc->resolution - 1, 0);
> struct spi_message msg;
> struct spi_transfer tx[] = {
> {
> .rx_buf = &ad7949_adc->buffer,
> .len = 2,
> - .bits_per_word = bits_per_word,
> + .bits_per_word = ad7949_adc->bits_per_word,
> },
> };
>
> @@ -147,7 +178,24 @@ static int ad7949_spi_read_channel(struct
> ad7949_adc_chip *ad7949_adc, int *val,
>
> ad7949_adc->current_channel = channel;
>
> - *val = ad7949_adc->buffer & mask;
> + switch (ad7949_adc->bits_per_word) {
> + case 16:
> + *val = ad7949_adc->buffer;
> + /* Shift-out padding bits */
> + if (ad7949_adc->resolution == 14)
> + *val = *val >> 2;
> + break;
> + case 14:
> + *val = ad7949_adc->buffer & GENMASK(13, 0);
> + break;
> + case 8:
> + /* Convert byte array to u16, MSB first */
> + *val = (ad7949_adc->buf8[0] << 8) | ad7949_adc-
> >buf8[1];
> + /* Shift-out padding bits */
> + if (ad7949_adc->resolution == 14)
> + *val = *val >> 2;
> + break;
> + }
>
> return 0;
> }
> @@ -280,6 +328,7 @@ static int ad7949_spi_probe(struct spi_device
> *spi)
> spec = &ad7949_adc_spec[spi_get_device_id(spi)-
> >driver_data];
> indio_dev->num_channels = spec->num_channels;
> ad7949_adc->resolution = spec->resolution;
> + ad7949_set_bits_per_word(ad7949_adc);
>
> ad7949_adc->vref = devm_regulator_get(dev, "vref");
> if (IS_ERR(ad7949_adc->vref)) {
> --
> 2.30.1.489.g328c10930387
> From: Liam Beguin <[email protected]>
> Sent: Friday, July 9, 2021 1:56 AM
> To: [email protected]; [email protected]; Hennerich, Michael
> <[email protected]>; [email protected]; charles-
> [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: [PATCH v1 3/4] iio: adc: ad7949: add support for internal vref
>
> [External]
>
> From: Liam Beguin <[email protected]>
>
> Add support for selecting a custom reference voltage from the
> devicetree. If an external source is used, a vref regulator should be
> defined in the devicetree.
>
> Signed-off-by: Liam Beguin <[email protected]>
> ---
> drivers/iio/adc/ad7949.c | 84
> +++++++++++++++++++++++++++++++++-------
> 1 file changed, 69 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
> index bbc6b56330a3..3c1293922d2e 100644
> --- a/drivers/iio/adc/ad7949.c
> +++ b/drivers/iio/adc/ad7949.c
> @@ -31,6 +31,7 @@
> #define AD7949_CFG_VAL_BW_FULL 1
> #define AD7949_CFG_VAL_BW_QUARTER 0
> #define AD7949_CFG_BIT_REF GENMASK(5, 3)
> +#define AD7949_CFG_VAL_REF_EXTERNAL BIT(1)
> #define AD7949_CFG_BIT_SEQ GENMASK(2, 1)
> #define AD7949_CFG_BIT_RBN BIT(0)
>
> @@ -40,6 +41,33 @@ enum {
> ID_AD7689,
> };
>
> +/**
> + * enum ad7949_ref - Reference selection
> + *
> + * AD7949_REF_INT_2500: Internal reference and temperature
> sensor enabled.
> + * Vref=2.5V, buffered output
> + * AD7949_REF_INT_4096: Internal reference and temperature
> sensor enabled.
> + * Vref=4.096V, buffered output
> + * AD7949_REF_EXT_TEMP: Use external reference, temperature
> sensor enabled.
> + * Internal buffer disabled
> + * AD7949_REF_EXT_TEMP_BUF: Use external reference, internal
> buffer and
> + * temperature sensor enabled.
> + * AD7949_REF_RSRV_4: Do not use
> + * AD7949_REF_RSRV_5: Do not use
> + * AD7949_REF_EXT: Use external reference, internal buffer and
> + * temperature sensor disabled.
> + * AD7949_REF_EXT_BUF: Use external reference, internal buffer
> enabled.
> + * Internal reference and temperature sensor disabled.
> + */
> +enum ad7949_ref {
> + AD7949_REF_INT_2500 = 0,
> + AD7949_REF_INT_4096,
> + AD7949_REF_EXT_TEMP,
> + AD7949_REF_EXT_TEMP_BUF,
> + AD7949_REF_EXT = 6,
> + AD7949_REF_EXT_BUF,
> +};
> +
> struct ad7949_adc_spec {
> u8 num_channels;
> u8 resolution;
> @@ -55,6 +83,7 @@ static const struct ad7949_adc_spec
> ad7949_adc_spec[] = {
> * struct ad7949_adc_chip - AD ADC chip
> * @lock: protects write sequences
> * @vref: regulator generating Vref
> + * @refsel: reference selection
> * @indio_dev: reference to iio structure
> * @spi: reference to spi structure
> * @resolution: resolution of the chip
> @@ -66,6 +95,7 @@ static const struct ad7949_adc_spec
> ad7949_adc_spec[] = {
> struct ad7949_adc_chip {
> struct mutex lock;
> struct regulator *vref;
> + enum ad7949_ref refsel;
> struct iio_dev *indio_dev;
> struct spi_device *spi;
> u8 resolution;
> @@ -241,12 +271,28 @@ static int ad7949_spi_read_raw(struct iio_dev
> *indio_dev,
> return IIO_VAL_INT;
>
> case IIO_CHAN_INFO_SCALE:
> - ret = regulator_get_voltage(ad7949_adc->vref);
> - if (ret < 0)
> - return ret;
> + switch (ad7949_adc->refsel) {
> + case AD7949_REF_INT_2500:
> + *val = 2500;
> + break;
> + case AD7949_REF_INT_4096:
> + *val = 4096;
> + break;
> + case AD7949_REF_EXT_TEMP:
> + case AD7949_REF_EXT_TEMP_BUF:
> + case AD7949_REF_EXT:
> + case AD7949_REF_EXT_BUF:
> + ret = regulator_get_voltage(ad7949_adc-
> >vref);
> + if (ret < 0)
> + return ret;
> +
> + /* convert value back to mV */
> + *val = ret / 1000;
> + break;
> + }
>
> - *val = ret / 5000;
> - return IIO_VAL_INT;
> + *val2 = (1 << ad7949_adc->resolution) - 1;
> + return IIO_VAL_FRACTIONAL;
> }
>
> return -EINVAL;
> @@ -285,7 +331,7 @@ static int ad7949_spi_init(struct
> ad7949_adc_chip *ad7949_adc)
> FIELD_PREP(AD7949_CFG_BIT_INCC,
> AD7949_CFG_VAL_INCC_UNIPOLAR_GND) |
> FIELD_PREP(AD7949_CFG_BIT_INX, ad7949_adc-
> >current_channel) |
> FIELD_PREP(AD7949_CFG_BIT_BW,
> AD7949_CFG_VAL_BW_FULL) |
> - FIELD_PREP(AD7949_CFG_BIT_REF,
> AD7949_REF_EXT_BUF) |
> + FIELD_PREP(AD7949_CFG_BIT_REF, ad7949_adc-
> >refsel) |
> FIELD_PREP(AD7949_CFG_BIT_SEQ, 0x0) |
> FIELD_PREP(AD7949_CFG_BIT_RBN, 1);
>
> @@ -304,6 +350,7 @@ static int ad7949_spi_init(struct
> ad7949_adc_chip *ad7949_adc)
> static int ad7949_spi_probe(struct spi_device *spi)
> {
> struct device *dev = &spi->dev;
> + struct device_node *np = dev->of_node;
> const struct ad7949_adc_spec *spec;
> struct ad7949_adc_chip *ad7949_adc;
> struct iio_dev *indio_dev;
> @@ -315,6 +362,7 @@ static int ad7949_spi_probe(struct spi_device
> *spi)
> return -ENOMEM;
> }
>
> + indio_dev->dev.of_node = np;
Why doing this? The IIO core will do it for us at register time.
> indio_dev->info = &ad7949_spi_info;
> indio_dev->name = spi_get_device_id(spi)->name;
> indio_dev->modes = INDIO_DIRECT_MODE;
> @@ -330,16 +378,22 @@ static int ad7949_spi_probe(struct spi_device
> *spi)
> ad7949_adc->resolution = spec->resolution;
> ad7949_set_bits_per_word(ad7949_adc);
>
> - ad7949_adc->vref = devm_regulator_get(dev, "vref");
> - if (IS_ERR(ad7949_adc->vref)) {
> - dev_err(dev, "fail to request regulator\n");
> - return PTR_ERR(ad7949_adc->vref);
> - }
> + /* Set default devicetree parameters */
> + ad7949_adc->refsel = AD7949_REF_EXT_BUF;
> + of_property_read_u32(np, "adi,reference-select",
> &ad7949_adc->refsel);
In case the property is given, we should make sure we get a valid
value and error out if not...
- Nuno S?
> - ret = regulator_enable(ad7949_adc->vref);
> - if (ret < 0) {
> - dev_err(dev, "fail to enable regulator\n");
> - return ret;
> + if (ad7949_adc->refsel & AD7949_CFG_VAL_REF_EXTERNAL) {
> + ad7949_adc->vref = devm_regulator_get(dev, "vref");
> + if (IS_ERR(ad7949_adc->vref)) {
> + dev_err(dev, "fail to request regulator\n");
> + return PTR_ERR(ad7949_adc->vref);
> + }
> +
> + ret = regulator_enable(ad7949_adc->vref);
> + if (ret < 0) {
> + dev_err(dev, "fail to enable regulator\n");
> + return ret;
> + }
> }
>
> mutex_init(&ad7949_adc->lock);
> --
> 2.30.1.489.g328c10930387
Hi Nuno,
On Fri Jul 9, 2021 at 4:15 AM EDT, Sa, Nuno wrote:
>
>
> > -----Original Message-----
> > From: Liam Beguin <[email protected]>
> > Sent: Friday, July 9, 2021 1:56 AM
> > To: [email protected]; [email protected]; Hennerich, Michael
> > <[email protected]>; [email protected]; charles-
> > [email protected]
> > Cc: [email protected]; [email protected];
> > [email protected]; [email protected]
> > Subject: [PATCH v1 4/4] dt-bindings: iio: adc: ad7949: add
> > adi,reference-source
> >
> > [External]
> >
> > From: Liam Beguin <[email protected]>
> >
> > Add bindings documentation for the adi,reference-source property.
> > This property is required to properly configure the ADC sample request
> > based on which reference source should be used for the calculation.
> >
> > Signed-off-by: Liam Beguin <[email protected]>
> > ---
> > .../bindings/iio/adc/adi,ad7949.yaml | 22 +++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > index 9b56bd4d5510..3f4629281cc8 100644
> > --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > @@ -35,6 +35,28 @@ properties:
> > "#io-channel-cells":
> > const: 1
> >
> > + adi,reference-select:
> > + allOf:
> > + - $ref: /schemas/types.yaml#/definitions/uint32
> > + - enum: [0, 1, 2, 3, 6, 7]
> > +
> > + default: 7
> > + description: |
> > + Select the reference voltage source to use when converting
> > samples.
> > + Acceptable values are:
> > + - 0: Internal reference and temperature sensor enabled.
> > + Vref=2.5V, buffered output
> > + - 1: Internal reference and temperature sensor enabled.
> > + Vref=4.096V, buffered output
> > + - 2: Use external reference, temperature sensor enabled.
> > + Internal buffer disabled
> > + - 3: Use external reference, internal buffer and temperature
> > sensor
> > + enabled.
> > + - 6: Use external reference, internal buffer and temperature
> > sensor
> > + disabled.
> > + - 7: Use external reference, internal buffer enabled.
> > + Internal reference and temperature sensor disabled.
>
> I think typically the description comes first. I also don't think you
> need the 'allOf'(not even sure if it will pass the binding check)...
> Just have '$ref' and 'enum' on the same level.
>
Understood, I can reorder the patches so that the bindings come first.
I thought I based that part on the `example-schema.yaml`, but looking at
it again, it seems like you're right and the AllOf isn't required.
I did run the bindings check on this, but I'll fix it.
Thanks,
Liam
> - Nuno Sá
>
> > required:
> > - compatible
> > - reg
> > --
> > 2.30.1.489.g328c10930387
On Fri Jul 9, 2021 at 4:19 AM EDT, Sa, Nuno wrote:
>
>
> > -----Original Message-----
> > From: Liam Beguin <[email protected]>
> > Sent: Friday, July 9, 2021 1:56 AM
> > To: [email protected]; [email protected]; Hennerich, Michael
> > <[email protected]>; [email protected]; charles-
> > [email protected]
> > Cc: [email protected]; [email protected];
> > [email protected]; [email protected]
> > Subject: [PATCH v1 2/4] iio: adc: ad7949: fix spi messages on non 14-bit
> > controllers
> >
> > [External]
> >
> > From: Liam Beguin <[email protected]>
> >
> > This driver supports devices with 14-bit and 16-bit sample sizes.
> > This is not always handled properly by spi controllers and can fail. To
> > work around this limitation, pad samples to 16-bit and split the sample
> > into two 8-bit messages in the event that only 8-bit messages are
> > supported by the controller.
> >
> > Signed-off-by: Liam Beguin <[email protected]>
> > ---
> > drivers/iio/adc/ad7949.c | 67
> > ++++++++++++++++++++++++++++++++++------
> > 1 file changed, 58 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
> > index 93aacf4f680b..bbc6b56330a3 100644
> > --- a/drivers/iio/adc/ad7949.c
> > +++ b/drivers/iio/adc/ad7949.c
> > @@ -11,6 +11,7 @@
> > #include <linux/module.h>
> > #include <linux/regulator/consumer.h>
> > #include <linux/spi/spi.h>
> > +#include <linux/bitfield.h>
> >
> > #define AD7949_MASK_TOTAL GENMASK(13, 0)
> > #define AD7949_CFG_REG_SIZE_BITS 14
> > @@ -57,6 +58,7 @@ static const struct ad7949_adc_spec
> > ad7949_adc_spec[] = {
> > * @indio_dev: reference to iio structure
> > * @spi: reference to spi structure
> > * @resolution: resolution of the chip
> > + * @bits_per_word: number of bits per SPI word
> > * @cfg: copy of the configuration register
> > * @current_channel: current channel in use
> > * @buffer: buffer to send / receive data to / from device
> > @@ -67,28 +69,59 @@ struct ad7949_adc_chip {
> > struct iio_dev *indio_dev;
> > struct spi_device *spi;
> > u8 resolution;
> > + u8 bits_per_word;
> > u16 cfg;
> > unsigned int current_channel;
> > - u16 buffer ____cacheline_aligned;
> > + union {
> > + __be16 buffer;
> > + u8 buf8[2];
> > + } ____cacheline_aligned;
> > };
> >
> > +static void ad7949_set_bits_per_word(struct ad7949_adc_chip
> > *ad7949_adc)
> > +{
> > + u32 adc_mask = SPI_BPW_MASK(ad7949_adc->resolution);
> > + u32 bpw = adc_mask & ad7949_adc->spi->controller-
> > >bits_per_word_mask;
> > +
> > + if (bpw == adc_mask)
> > + ad7949_adc->bits_per_word = ad7949_adc-
> > >resolution;
> > + else if (bpw == SPI_BPW_MASK(16))
> > + ad7949_adc->bits_per_word = 16;
> > + else
> > + ad7949_adc->bits_per_word = 8;
> > +}
> > +
> > static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc,
> > u16 val,
> > u16 mask)
> > {
> > int ret;
> > - int bits_per_word = ad7949_adc->resolution;
> > - int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS;
> > struct spi_message msg;
> > struct spi_transfer tx[] = {
> > {
> > .tx_buf = &ad7949_adc->buffer,
> > .len = 2,
> > - .bits_per_word = bits_per_word,
> > + .bits_per_word = ad7949_adc->bits_per_word,
> > },
> > };
> >
> > + ad7949_adc->buffer = 0;
> > ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask);
> > - ad7949_adc->buffer = ad7949_adc->cfg << shift;
> > +
> > + switch (ad7949_adc->bits_per_word) {
> > + case 16:
> > + ad7949_adc->buffer = ad7949_adc->cfg << 2;
> > + break;
> > + case 14:
> > + ad7949_adc->buffer = ad7949_adc->cfg;
> > + break;
> > + case 8:
> > + /* Pack 14-bit value into 2 bytes, MSB first */
> > + ad7949_adc->buf8[0] = FIELD_GET(GENMASK(13, 6),
> > ad7949_adc->cfg);
> > + ad7949_adc->buf8[1] = FIELD_GET(GENMASK(5, 0),
> > ad7949_adc->cfg);
> > + ad7949_adc->buf8[1] = ad7949_adc->buf8[1] << 2;
> > + break;
> > + }
>
> Honestly I didn't went through the driver but just a question... Are we
> sure that 'ad7949_adc->resolution' will have something valid (8, 14,
> 16)?
> A default statement is always a nice to have :).
>
Thanks for pointing that out. You're right that based on this driver
there's no guaranty that `ad7949_adc->resolution` will have a valid
value. I'll add a default to 8-bit.
Thanks,
Liam
> > spi_message_init_with_transfers(&msg, tx, 1);
> > ret = spi_sync(ad7949_adc->spi, &msg);
> >
> > @@ -105,14 +138,12 @@ static int ad7949_spi_read_channel(struct
> > ad7949_adc_chip *ad7949_adc, int *val,
> > {
> > int ret;
> > int i;
> > - int bits_per_word = ad7949_adc->resolution;
> > - int mask = GENMASK(ad7949_adc->resolution - 1, 0);
> > struct spi_message msg;
> > struct spi_transfer tx[] = {
> > {
> > .rx_buf = &ad7949_adc->buffer,
> > .len = 2,
> > - .bits_per_word = bits_per_word,
> > + .bits_per_word = ad7949_adc->bits_per_word,
> > },
> > };
> >
> > @@ -147,7 +178,24 @@ static int ad7949_spi_read_channel(struct
> > ad7949_adc_chip *ad7949_adc, int *val,
> >
> > ad7949_adc->current_channel = channel;
> >
> > - *val = ad7949_adc->buffer & mask;
> > + switch (ad7949_adc->bits_per_word) {
> > + case 16:
> > + *val = ad7949_adc->buffer;
> > + /* Shift-out padding bits */
> > + if (ad7949_adc->resolution == 14)
> > + *val = *val >> 2;
> > + break;
> > + case 14:
> > + *val = ad7949_adc->buffer & GENMASK(13, 0);
> > + break;
> > + case 8:
> > + /* Convert byte array to u16, MSB first */
> > + *val = (ad7949_adc->buf8[0] << 8) | ad7949_adc-
> > >buf8[1];
> > + /* Shift-out padding bits */
> > + if (ad7949_adc->resolution == 14)
> > + *val = *val >> 2;
> > + break;
> > + }
> >
> > return 0;
> > }
> > @@ -280,6 +328,7 @@ static int ad7949_spi_probe(struct spi_device
> > *spi)
> > spec = &ad7949_adc_spec[spi_get_device_id(spi)-
> > >driver_data];
> > indio_dev->num_channels = spec->num_channels;
> > ad7949_adc->resolution = spec->resolution;
> > + ad7949_set_bits_per_word(ad7949_adc);
> >
> > ad7949_adc->vref = devm_regulator_get(dev, "vref");
> > if (IS_ERR(ad7949_adc->vref)) {
> > --
> > 2.30.1.489.g328c10930387
On Fri Jul 9, 2021 at 4:15 AM EDT, Sa, Nuno wrote:
>
>
> > -----Original Message-----
> > From: Liam Beguin <[email protected]>
> > Sent: Friday, July 9, 2021 1:56 AM
> > To: [email protected]; [email protected]; Hennerich, Michael
> > <[email protected]>; [email protected]; charles-
> > [email protected]
> > Cc: [email protected]; [email protected];
> > [email protected]; [email protected]
> > Subject: [PATCH v1 4/4] dt-bindings: iio: adc: ad7949: add
> > adi,reference-source
> >
> > [External]
> >
> > From: Liam Beguin <[email protected]>
> >
> > Add bindings documentation for the adi,reference-source property.
> > This property is required to properly configure the ADC sample request
> > based on which reference source should be used for the calculation.
> >
> > Signed-off-by: Liam Beguin <[email protected]>
> > ---
> > .../bindings/iio/adc/adi,ad7949.yaml | 22 +++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > index 9b56bd4d5510..3f4629281cc8 100644
> > --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7949.yaml
> > @@ -35,6 +35,28 @@ properties:
> > "#io-channel-cells":
> > const: 1
> >
> > + adi,reference-select:
> > + allOf:
> > + - $ref: /schemas/types.yaml#/definitions/uint32
> > + - enum: [0, 1, 2, 3, 6, 7]
> > +
> > + default: 7
> > + description: |
> > + Select the reference voltage source to use when converting
> > samples.
> > + Acceptable values are:
> > + - 0: Internal reference and temperature sensor enabled.
> > + Vref=2.5V, buffered output
> > + - 1: Internal reference and temperature sensor enabled.
> > + Vref=4.096V, buffered output
> > + - 2: Use external reference, temperature sensor enabled.
> > + Internal buffer disabled
> > + - 3: Use external reference, internal buffer and temperature
> > sensor
> > + enabled.
> > + - 6: Use external reference, internal buffer and temperature
> > sensor
> > + disabled.
> > + - 7: Use external reference, internal buffer enabled.
> > + Internal reference and temperature sensor disabled.
>
> I think typically the description comes first. I also don't think you
> need the 'allOf'(not even sure if it will pass the binding check)...
> Just have '$ref' and 'enum' on the same level.
>
I realize I misread your comment on the order of the description. I'll
move it at the top of the binding definition.
Liam
> - Nuno Sá
>
> > required:
> > - compatible
> > - reg
> > --
> > 2.30.1.489.g328c10930387
On Fri Jul 9, 2021 at 4:23 AM EDT, Sa, Nuno wrote:
> > From: Liam Beguin <[email protected]>
> > Sent: Friday, July 9, 2021 1:56 AM
> > To: [email protected]; [email protected]; Hennerich, Michael
> > <[email protected]>; [email protected]; charles-
> > [email protected]
> > Cc: [email protected]; [email protected];
> > [email protected]; [email protected]
> > Subject: [PATCH v1 3/4] iio: adc: ad7949: add support for internal vref
> >
> > [External]
> >
> > From: Liam Beguin <[email protected]>
> >
> > Add support for selecting a custom reference voltage from the
> > devicetree. If an external source is used, a vref regulator should be
> > defined in the devicetree.
> >
> > Signed-off-by: Liam Beguin <[email protected]>
> > ---
> > drivers/iio/adc/ad7949.c | 84
> > +++++++++++++++++++++++++++++++++-------
> > 1 file changed, 69 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
> > index bbc6b56330a3..3c1293922d2e 100644
> > --- a/drivers/iio/adc/ad7949.c
> > +++ b/drivers/iio/adc/ad7949.c
> > @@ -31,6 +31,7 @@
> > #define AD7949_CFG_VAL_BW_FULL 1
> > #define AD7949_CFG_VAL_BW_QUARTER 0
> > #define AD7949_CFG_BIT_REF GENMASK(5, 3)
> > +#define AD7949_CFG_VAL_REF_EXTERNAL BIT(1)
> > #define AD7949_CFG_BIT_SEQ GENMASK(2, 1)
> > #define AD7949_CFG_BIT_RBN BIT(0)
> >
> > @@ -40,6 +41,33 @@ enum {
> > ID_AD7689,
> > };
> >
> > +/**
> > + * enum ad7949_ref - Reference selection
> > + *
> > + * AD7949_REF_INT_2500: Internal reference and temperature
> > sensor enabled.
> > + * Vref=2.5V, buffered output
> > + * AD7949_REF_INT_4096: Internal reference and temperature
> > sensor enabled.
> > + * Vref=4.096V, buffered output
> > + * AD7949_REF_EXT_TEMP: Use external reference, temperature
> > sensor enabled.
> > + * Internal buffer disabled
> > + * AD7949_REF_EXT_TEMP_BUF: Use external reference, internal
> > buffer and
> > + * temperature sensor enabled.
> > + * AD7949_REF_RSRV_4: Do not use
> > + * AD7949_REF_RSRV_5: Do not use
> > + * AD7949_REF_EXT: Use external reference, internal buffer and
> > + * temperature sensor disabled.
> > + * AD7949_REF_EXT_BUF: Use external reference, internal buffer
> > enabled.
> > + * Internal reference and temperature sensor disabled.
> > + */
> > +enum ad7949_ref {
> > + AD7949_REF_INT_2500 = 0,
> > + AD7949_REF_INT_4096,
> > + AD7949_REF_EXT_TEMP,
> > + AD7949_REF_EXT_TEMP_BUF,
> > + AD7949_REF_EXT = 6,
> > + AD7949_REF_EXT_BUF,
> > +};
> > +
> > struct ad7949_adc_spec {
> > u8 num_channels;
> > u8 resolution;
> > @@ -55,6 +83,7 @@ static const struct ad7949_adc_spec
> > ad7949_adc_spec[] = {
> > * struct ad7949_adc_chip - AD ADC chip
> > * @lock: protects write sequences
> > * @vref: regulator generating Vref
> > + * @refsel: reference selection
> > * @indio_dev: reference to iio structure
> > * @spi: reference to spi structure
> > * @resolution: resolution of the chip
> > @@ -66,6 +95,7 @@ static const struct ad7949_adc_spec
> > ad7949_adc_spec[] = {
> > struct ad7949_adc_chip {
> > struct mutex lock;
> > struct regulator *vref;
> > + enum ad7949_ref refsel;
> > struct iio_dev *indio_dev;
> > struct spi_device *spi;
> > u8 resolution;
> > @@ -241,12 +271,28 @@ static int ad7949_spi_read_raw(struct iio_dev
> > *indio_dev,
> > return IIO_VAL_INT;
> >
> > case IIO_CHAN_INFO_SCALE:
> > - ret = regulator_get_voltage(ad7949_adc->vref);
> > - if (ret < 0)
> > - return ret;
> > + switch (ad7949_adc->refsel) {
> > + case AD7949_REF_INT_2500:
> > + *val = 2500;
> > + break;
> > + case AD7949_REF_INT_4096:
> > + *val = 4096;
> > + break;
> > + case AD7949_REF_EXT_TEMP:
> > + case AD7949_REF_EXT_TEMP_BUF:
> > + case AD7949_REF_EXT:
> > + case AD7949_REF_EXT_BUF:
> > + ret = regulator_get_voltage(ad7949_adc-
> > >vref);
> > + if (ret < 0)
> > + return ret;
> > +
> > + /* convert value back to mV */
> > + *val = ret / 1000;
> > + break;
> > + }
> >
> > - *val = ret / 5000;
> > - return IIO_VAL_INT;
> > + *val2 = (1 << ad7949_adc->resolution) - 1;
> > + return IIO_VAL_FRACTIONAL;
> > }
> >
> > return -EINVAL;
> > @@ -285,7 +331,7 @@ static int ad7949_spi_init(struct
> > ad7949_adc_chip *ad7949_adc)
> > FIELD_PREP(AD7949_CFG_BIT_INCC,
> > AD7949_CFG_VAL_INCC_UNIPOLAR_GND) |
> > FIELD_PREP(AD7949_CFG_BIT_INX, ad7949_adc-
> > >current_channel) |
> > FIELD_PREP(AD7949_CFG_BIT_BW,
> > AD7949_CFG_VAL_BW_FULL) |
> > - FIELD_PREP(AD7949_CFG_BIT_REF,
> > AD7949_REF_EXT_BUF) |
> > + FIELD_PREP(AD7949_CFG_BIT_REF, ad7949_adc-
> > >refsel) |
> > FIELD_PREP(AD7949_CFG_BIT_SEQ, 0x0) |
> > FIELD_PREP(AD7949_CFG_BIT_RBN, 1);
> >
> > @@ -304,6 +350,7 @@ static int ad7949_spi_init(struct
> > ad7949_adc_chip *ad7949_adc)
> > static int ad7949_spi_probe(struct spi_device *spi)
> > {
> > struct device *dev = &spi->dev;
> > + struct device_node *np = dev->of_node;
> > const struct ad7949_adc_spec *spec;
> > struct ad7949_adc_chip *ad7949_adc;
> > struct iio_dev *indio_dev;
> > @@ -315,6 +362,7 @@ static int ad7949_spi_probe(struct spi_device
> > *spi)
> > return -ENOMEM;
> > }
> >
> > + indio_dev->dev.of_node = np;
>
> Why doing this? The IIO core will do it for us at register time.
Sorry about that, will drop.
>
> > indio_dev->info = &ad7949_spi_info;
> > indio_dev->name = spi_get_device_id(spi)->name;
> > indio_dev->modes = INDIO_DIRECT_MODE;
> > @@ -330,16 +378,22 @@ static int ad7949_spi_probe(struct spi_device
> > *spi)
> > ad7949_adc->resolution = spec->resolution;
> > ad7949_set_bits_per_word(ad7949_adc);
> >
> > - ad7949_adc->vref = devm_regulator_get(dev, "vref");
> > - if (IS_ERR(ad7949_adc->vref)) {
> > - dev_err(dev, "fail to request regulator\n");
> > - return PTR_ERR(ad7949_adc->vref);
> > - }
> > + /* Set default devicetree parameters */
> > + ad7949_adc->refsel = AD7949_REF_EXT_BUF;
> > + of_property_read_u32(np, "adi,reference-select",
> > &ad7949_adc->refsel);
>
> In case the property is given, we should make sure we get a valid
> value and error out if not...
>
I thought it would be handled later on when processing the sample, but
it's not really and it's better to fail early. I'll add that to v2.
Thanks,
Liam
> - Nuno Sá
> > - ret = regulator_enable(ad7949_adc->vref);
> > - if (ret < 0) {
> > - dev_err(dev, "fail to enable regulator\n");
> > - return ret;
> > + if (ad7949_adc->refsel & AD7949_CFG_VAL_REF_EXTERNAL) {
> > + ad7949_adc->vref = devm_regulator_get(dev, "vref");
> > + if (IS_ERR(ad7949_adc->vref)) {
> > + dev_err(dev, "fail to request regulator\n");
> > + return PTR_ERR(ad7949_adc->vref);
> > + }
> > +
> > + ret = regulator_enable(ad7949_adc->vref);
> > + if (ret < 0) {
> > + dev_err(dev, "fail to enable regulator\n");
> > + return ret;
> > + }
> > }
> >
> > mutex_init(&ad7949_adc->lock);
> > --
> > 2.30.1.489.g328c10930387