[PATCH 1/2] dt-bindings: iio: adf4371: add rdiv2 and doubler

[PATCH 1/2] dt-bindings: iio: adf4371: add rdiv2 and doubler

[Antoniu Miclaus]

Add support for reference doubler enable and reference divide by 2
clock.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
 .../devicetree/bindings/iio/frequency/adf4371.yaml    | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml b/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml
index 1cb2adaf66f9..ef241c38520c 100644
--- a/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml
+++ b/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml
@@ -40,6 +40,17 @@ properties:
       output stage will shut down until the ADF4371/ADF4372 achieves lock as
       measured by the digital lock detect circuitry.
 
+  adi,reference-doubler-enable:
+    type: boolean
+    description:
+      If this property is present, the reference doubler block is enabled.
+
+  adi,adi,reference-div2-enable:
+    type: boolean
+    description:
+      If this property is present, the reference divide by 2 clock is enabled.
+      This feature can be used to provide a 50% duty cycle signal to the PFD.
+
 required:
   - compatible
   - reg
-- 
2.47.0

[PATCH 2/2] iio: frequency: adf4371: add ref doubler and div2

[Antoniu Miclaus]

Add support for the reference doubler and the reference divide by 2
clock.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
 drivers/iio/frequency/adf4371.c | 37 +++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/frequency/adf4371.c b/drivers/iio/frequency/adf4371.c
index b27088464826..02d42652dfdd 100644
--- a/drivers/iio/frequency/adf4371.c
+++ b/drivers/iio/frequency/adf4371.c
@@ -41,6 +41,12 @@
 #define ADF4371_MOD2WORD_MSK		GENMASK(5, 0)
 #define ADF4371_MOD2WORD(x)		FIELD_PREP(ADF4371_MOD2WORD_MSK, x)
 
+/* ADF4371_REG22 */
+#define ADF4371_REF_DOUB_MASK		BIT(5)
+#define ADF4371_REF_DOUB(x)		FIELD_PREP(ADF4371_REF_DOUB_MASK, x)
+#define ADF4371_RDIV2_MASK		BIT(4)
+#define ADF4371_RDIV2(x)		FIELD_PREP(ADF4371_RDIV2_MASK, x)
+
 /* ADF4371_REG24 */
 #define ADF4371_RF_DIV_SEL_MSK		GENMASK(6, 4)
 #define ADF4371_RF_DIV_SEL(x)		FIELD_PREP(ADF4371_RF_DIV_SEL_MSK, x)
@@ -70,6 +76,9 @@
 #define ADF4371_MAX_FREQ_PFD		250000000UL /* Hz */
 #define ADF4371_MAX_FREQ_REFIN		600000000UL /* Hz */
 
+#define ADF4371_MIN_CLKIN_DOUB_FREQ	10000000ULL /* Hz */
+#define ADF4371_MAX_CLKIN_DOUB_FREQ	125000000ULL /* Hz */
+
 /* MOD1 is a 24-bit primary modulus with fixed value of 2^25 */
 #define ADF4371_MODULUS1		33554432ULL
 /* MOD2 is the programmable, 14-bit auxiliary fractional modulus */
@@ -175,6 +184,8 @@ struct adf4371_state {
 	unsigned int mod2;
 	unsigned int rf_div_sel;
 	unsigned int ref_div_factor;
+	bool ref_doubler_en;
+	bool ref_div2_en;
 	u8 buf[10] __aligned(IIO_DMA_MINALIGN);
 };
 
@@ -497,22 +508,44 @@ static int adf4371_setup(struct adf4371_state *st)
 			return ret;
 	}
 
+	if (device_property_read_bool(&st->spi->dev,
+				      "adi,reference-doubler-enable"))
+		st->ref_doubler_en = true;
+
+	if (device_property_read_bool(&st->spi->dev,
+				      "adi,reference-div2-enable"))
+		st->ref_div2_en = true;
+
 	/* Set address in ascending order, so the bulk_write() will work */
 	ret = regmap_update_bits(st->regmap, ADF4371_REG(0x0),
 				 ADF4371_ADDR_ASC_MSK | ADF4371_ADDR_ASC_R_MSK,
 				 ADF4371_ADDR_ASC(1) | ADF4371_ADDR_ASC_R(1));
 	if (ret < 0)
 		return ret;
+
+	if (st->ref_doubler_en &&
+	    (st->clkin_freq > ADF4371_MAX_CLKIN_DOUB_FREQ ||
+	     st->clkin_freq < ADF4371_MIN_CLKIN_DOUB_FREQ))
+		st->ref_doubler_en = false;
+
+	ret = regmap_update_bits(st->regmap,  ADF4371_REG(0x22),
+				 ADF4371_REF_DOUB_MASK |
+				 ADF4371_RDIV2_MASK,
+				 ADF4371_REF_DOUB(st->ref_doubler_en) |
+				 ADF4371_RDIV2(st->ref_div2_en));
+	if (ret < 0)
+		return ret;
+
 	/*
 	 * Calculate and maximize PFD frequency
 	 * fPFD = REFIN × ((1 + D)/(R × (1 + T)))
 	 * Where D is the REFIN doubler bit, T is the reference divide by 2,
 	 * R is the reference division factor
-	 * TODO: it is assumed D and T equal 0.
 	 */
 	do {
 		st->ref_div_factor++;
-		st->fpfd = st->clkin_freq / st->ref_div_factor;
+		st->fpfd = (st->clkin_freq * (st->ref_doubler_en ? 2 : 1)) /
+			   (st->ref_div_factor * (st->ref_div2_en ? 2 : 1));
 	} while (st->fpfd > ADF4371_MAX_FREQ_PFD);
 
 	/* Calculate Timeouts */
-- 
2.47.0

Re: [PATCH 1/2] dt-bindings: iio: adf4371: add rdiv2 and doubler

[Jonathan Cameron]

On Fri, 22 Nov 2024 13:32:13 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add support for reference doubler enable and reference divide by 2
> clock.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>

why are these not things that are derivable from the required output
frequency vs the clock frequency that comes in?

Would have been good perhaps to have a cover letter with some description
of how these features are used in practice.

Thanks,

Jonathan


> ---
>  .../devicetree/bindings/iio/frequency/adf4371.yaml    | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml b/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml
> index 1cb2adaf66f9..ef241c38520c 100644
> --- a/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml
> +++ b/Documentation/devicetree/bindings/iio/frequency/adf4371.yaml
> @@ -40,6 +40,17 @@ properties:
>        output stage will shut down until the ADF4371/ADF4372 achieves lock as
>        measured by the digital lock detect circuitry.
>  
> +  adi,reference-doubler-enable:
> +    type: boolean
> +    description:
> +      If this property is present, the reference doubler block is enabled.
> +
> +  adi,adi,reference-div2-enable:
> +    type: boolean
> +    description:
> +      If this property is present, the reference divide by 2 clock is enabled.
> +      This feature can be used to provide a 50% duty cycle signal to the PFD.
> +
>  required:
>    - compatible
>    - reg

Re: [PATCH 2/2] iio: frequency: adf4371: add ref doubler and div2

[Jonathan Cameron]

On Fri, 22 Nov 2024 13:32:14 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add support for the reference doubler and the reference divide by 2
> clock.
The question of 'why' these would be set in firmware remains, but
a few trivial comments inline on the implementation.


> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
>  drivers/iio/frequency/adf4371.c | 37 +++++++++++++++++++++++++++++++--
>  1 file changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/frequency/adf4371.c b/drivers/iio/frequency/adf4371.c
> index b27088464826..02d42652dfdd 100644
> --- a/drivers/iio/frequency/adf4371.c
> +++ b/drivers/iio/frequency/adf4371.c
> @@ -41,6 +41,12 @@
>  #define ADF4371_MOD2WORD_MSK		GENMASK(5, 0)
>  #define ADF4371_MOD2WORD(x)		FIELD_PREP(ADF4371_MOD2WORD_MSK, x)
>  
> +/* ADF4371_REG22 */
> +#define ADF4371_REF_DOUB_MASK		BIT(5)
> +#define ADF4371_REF_DOUB(x)		FIELD_PREP(ADF4371_REF_DOUB_MASK, x)
> +#define ADF4371_RDIV2_MASK		BIT(4)
> +#define ADF4371_RDIV2(x)		FIELD_PREP(ADF4371_RDIV2_MASK, x)
> +
>  /* ADF4371_REG24 */
>  #define ADF4371_RF_DIV_SEL_MSK		GENMASK(6, 4)
>  #define ADF4371_RF_DIV_SEL(x)		FIELD_PREP(ADF4371_RF_DIV_SEL_MSK, x)
> @@ -70,6 +76,9 @@
>  #define ADF4371_MAX_FREQ_PFD		250000000UL /* Hz */
>  #define ADF4371_MAX_FREQ_REFIN		600000000UL /* Hz */
>  
> +#define ADF4371_MIN_CLKIN_DOUB_FREQ	10000000ULL /* Hz */
> +#define ADF4371_MAX_CLKIN_DOUB_FREQ	125000000ULL /* Hz */
> +
>  /* MOD1 is a 24-bit primary modulus with fixed value of 2^25 */
>  #define ADF4371_MODULUS1		33554432ULL
>  /* MOD2 is the programmable, 14-bit auxiliary fractional modulus */
> @@ -175,6 +184,8 @@ struct adf4371_state {
>  	unsigned int mod2;
>  	unsigned int rf_div_sel;
>  	unsigned int ref_div_factor;
> +	bool ref_doubler_en;
> +	bool ref_div2_en;
>  	u8 buf[10] __aligned(IIO_DMA_MINALIGN);
>  };
>  
> @@ -497,22 +508,44 @@ static int adf4371_setup(struct adf4371_state *st)
>  			return ret;
>  	}
>  
> +	if (device_property_read_bool(&st->spi->dev,
> +				      "adi,reference-doubler-enable"))
> +		st->ref_doubler_en = true;
> +
> +	if (device_property_read_bool(&st->spi->dev,
> +				      "adi,reference-div2-enable"))
> +		st->ref_div2_en = true;
	st->ref_div2_en = device_property_read_bool(dev, "adi,reference-div2-enable");
Line is a bit long but more readable.
struct device *dev = &st->spi->dev; needed at top of function.
+ do the same for ref_doubler_en..

> +
>  	/* Set address in ascending order, so the bulk_write() will work */
>  	ret = regmap_update_bits(st->regmap, ADF4371_REG(0x0),
>  				 ADF4371_ADDR_ASC_MSK | ADF4371_ADDR_ASC_R_MSK,
>  				 ADF4371_ADDR_ASC(1) | ADF4371_ADDR_ASC_R(1));
>  	if (ret < 0)
>  		return ret;
> +
> +	if (st->ref_doubler_en &&
> +	    (st->clkin_freq > ADF4371_MAX_CLKIN_DOUB_FREQ ||
> +	     st->clkin_freq < ADF4371_MIN_CLKIN_DOUB_FREQ))
> +		st->ref_doubler_en = false;
> +
> +	ret = regmap_update_bits(st->regmap,  ADF4371_REG(0x22),
> +				 ADF4371_REF_DOUB_MASK |
> +				 ADF4371_RDIV2_MASK,
> +				 ADF4371_REF_DOUB(st->ref_doubler_en) |
> +				 ADF4371_RDIV2(st->ref_div2_en));
> +	if (ret < 0)
> +		return ret;
> +
>  	/*
>  	 * Calculate and maximize PFD frequency
>  	 * fPFD = REFIN × ((1 + D)/(R × (1 + T)))
>  	 * Where D is the REFIN doubler bit, T is the reference divide by 2,
>  	 * R is the reference division factor
> -	 * TODO: it is assumed D and T equal 0.
>  	 */
>  	do {
>  		st->ref_div_factor++;
> -		st->fpfd = st->clkin_freq / st->ref_div_factor;
> +		st->fpfd = (st->clkin_freq * (st->ref_doubler_en ? 2 : 1)) /
> +			   (st->ref_div_factor * (st->ref_div2_en ? 2 : 1));
>  	} while (st->fpfd > ADF4371_MAX_FREQ_PFD);
>  
>  	/* Calculate Timeouts */