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

[Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>]

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

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
---
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