[PATCH v4 2/3] iio: frequency: adf4371: add refin mode

Antoniu Miclaus
2025-01-09T13:37:36Z

Add support for single-ended/differential reference input mode.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
changes in v4:
- parse input clock depending on the name and adjust the refin mode
accordingly.
drivers/iio/frequency/adf4371.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/frequency/adf4371.c b/drivers/iio/frequency/adf4371.c
index b27088464826..50450e7b5464 100644
--- a/drivers/iio/frequency/adf4371.c
+++ b/drivers/iio/frequency/adf4371.c
@@ -41,6 +41,10 @@
#define ADF4371_MOD2WORD_MSK GENMASK(5, 0)
#define ADF4371_MOD2WORD(x) FIELD_PREP(ADF4371_MOD2WORD_MSK, x)

+/* ADF4371_REG22 */
+#define ADF4371_REFIN_MODE_MASK BIT(6)
+#define ADF4371_REFIN_MODE(x) FIELD_PREP(ADF4371_REFIN_MODE_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)
@@ -69,6 +73,7 @@

#define ADF4371_MAX_FREQ_PFD 250000000UL /* Hz */
#define ADF4371_MAX_FREQ_REFIN 600000000UL /* Hz */
+#define ADF4371_MAX_FREQ_REFIN_SE 500000000UL /* Hz */

/* MOD1 is a 24-bit primary modulus with fixed value of 2^25 */
#define ADF4371_MODULUS1 33554432ULL
@@ -175,6 +180,7 @@ struct adf4371_state {
unsigned int mod2;
unsigned int rf_div_sel;
unsigned int ref_div_factor;
+ bool ref_diff_en;
u8 buf[10] __aligned(IIO_DMA_MINALIGN);
};

@@ -503,6 +509,17 @@ static int adf4371_setup(struct adf4371_state *st)
ADF4371_ADDR_ASC(1) | ADF4371_ADDR_ASC_R(1));
if (ret < 0)
return ret;
+
+ if ((st->ref_diff_en && st->clkin_freq > ADF4371_MAX_FREQ_REFIN) ||
+ (!st->ref_diff_en && st->clkin_freq > ADF4371_MAX_FREQ_REFIN_SE))
+ return -EINVAL;
+
+ ret = regmap_update_bits(st->regmap, ADF4371_REG(0x22),
+ ADF4371_REFIN_MODE_MASK,
+ ADF4371_REFIN_MODE(st->ref_diff_en));
+ if (ret < 0)
+ return ret;
+
/*
* Calculate and maximize PFD frequency
* fPFD = REFIN × ((1 + D)/(R × (1 + T)))
@@ -572,9 +589,16 @@ static int adf4371_probe(struct spi_device *spi)
indio_dev->channels = st->chip_info->channels;
indio_dev->num_channels = st->chip_info->num_channels;

+ st->ref_diff_en = false;
+
st->clkin = devm_clk_get_enabled(&spi->dev, "clkin");
- if (IS_ERR(st->clkin))
- return PTR_ERR(st->clkin);
+ if (IS_ERR(st->clkin)) {
+ st->clkin = devm_clk_get_enabled(&spi->dev, "clkin-diff");
+ if (IS_ERR(st->clkin))
+ return PTR_ERR(st->clkin);
+
+ st->ref_diff_en = true;
+ }

st->clkin_freq = clk_get_rate(st->clkin);

--
2.47.1