[PATCH v4 3/3] iio: frequency: adf4371: add ref doubler

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

Add support for the reference doubler.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v4.
drivers/iio/frequency/adf4371.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/frequency/adf4371.c b/drivers/iio/frequency/adf4371.c
index 50450e7b5464..a57fc24a6799 100644
--- a/drivers/iio/frequency/adf4371.c
+++ b/drivers/iio/frequency/adf4371.c
@@ -44,6 +44,8 @@
/* ADF4371_REG22 */
#define ADF4371_REFIN_MODE_MASK BIT(6)
#define ADF4371_REFIN_MODE(x) FIELD_PREP(ADF4371_REFIN_MODE_MASK, x)
+#define ADF4371_REF_DOUB_MASK BIT(5)
+#define ADF4371_REF_DOUB(x) FIELD_PREP(ADF4371_REF_DOUB_MASK, x)\

/* ADF4371_REG24 */
#define ADF4371_RF_DIV_SEL_MSK GENMASK(6, 4)
@@ -75,6 +77,9 @@
#define ADF4371_MAX_FREQ_REFIN 600000000UL /* Hz */
#define ADF4371_MAX_FREQ_REFIN_SE 500000000UL /* 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 */
@@ -481,7 +486,7 @@ static const struct iio_info adf4371_info = {
static int adf4371_setup(struct adf4371_state *st)
{
unsigned int synth_timeout = 2, timeout = 1, vco_alc_timeout = 1;
- unsigned int vco_band_div, tmp;
+ unsigned int vco_band_div, tmp, ref_doubler_en = 0;
int ret;

/* Perform a software reset */
@@ -514,8 +519,14 @@ static int adf4371_setup(struct adf4371_state *st)
(!st->ref_diff_en && st->clkin_freq > ADF4371_MAX_FREQ_REFIN_SE))
return -EINVAL;

+ if (st->clkin_freq < ADF4371_MAX_CLKIN_DOUB_FREQ &&
+ st->clkin_freq > ADF4371_MIN_CLKIN_DOUB_FREQ)
+ ref_doubler_en = 1;
+
ret = regmap_update_bits(st->regmap, ADF4371_REG(0x22),
+ ADF4371_REF_DOUB_MASK |
ADF4371_REFIN_MODE_MASK,
+ ADF4371_REF_DOUB(ref_doubler_en) |
ADF4371_REFIN_MODE(st->ref_diff_en));
if (ret < 0)
return ret;
@@ -529,7 +540,8 @@ static int adf4371_setup(struct adf4371_state *st)
*/
do {
st->ref_div_factor++;
- st->fpfd = st->clkin_freq / st->ref_div_factor;
+ st->fpfd = st->clkin_freq * (1 + ref_doubler_en) /
+ st->ref_div_factor;
} while (st->fpfd > ADF4371_MAX_FREQ_PFD);

/* Calculate Timeouts */
--
2.47.1