iio: frequency: adf4371: add ref doubler

Add support for the reference doubler.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://patch.msgid.link/20250127101026.5320-4-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/frequency/adf4371.c b/drivers/iio/frequency/adf4371.c
index 41155af3c4f6f06c26dcee429ca964fa8bc2c708..9a84e81787b1120a12467a5375a0777a0ef7f7ec 100644 (file)
--- a/drivers/iio/frequency/adf4371.c
+++ b/drivers/iio/frequency/adf4371.c
@@ -45,6 +45,8 @@
 /* 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)
@@ -76,6 +78,9 @@
 #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 */
@@ -483,7 +488,7 @@ 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 */
@@ -516,8 +521,14 @@ 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;
@@ -531,7 +542,8 @@ 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 */