[PATCH v4 2/2] iio: frequency: adf4377: add clk provider support

[Antoniu Miclaus <antoniu.miclaus@analog.com>]

Add clk provider feature for the adf4377.

Even though the driver was sent as an IIO driver in most cases the
device is actually seen as a clock provider.

This patch aims to cover actual usecases requested by users in order to
completely control the output frequencies from userspace.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
changes in v4:
 - Split device_property_read_string() assignment from conditional check
 - Use %pfw format specifier
 - Add struct device *dev local variable
 drivers/iio/frequency/adf4377.c | 121 +++++++++++++++++++++++++++++++-
 1 file changed, 119 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/frequency/adf4377.c b/drivers/iio/frequency/adf4377.c
index 08833b7035e4..bbf82c03606f 100644
--- a/drivers/iio/frequency/adf4377.c
+++ b/drivers/iio/frequency/adf4377.c
@@ -8,6 +8,7 @@
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/clkdev.h>
 #include <linux/delay.h>
 #include <linux/device.h>
@@ -435,9 +436,14 @@ struct adf4377_state {
 	struct gpio_desc	*gpio_ce;
 	struct gpio_desc	*gpio_enclk1;
 	struct gpio_desc	*gpio_enclk2;
+	struct clk		*clk;
+	struct clk		*clkout;
+	struct clk_hw		hw;
 	u8			buf[2] __aligned(IIO_DMA_MINALIGN);
 };
 
+#define to_adf4377_state(h)	container_of(h, struct adf4377_state, hw)
+
 static const char * const adf4377_muxout_modes[] = {
 	[ADF4377_MUXOUT_HIGH_Z] = "high_z",
 	[ADF4377_MUXOUT_LKDET] = "lock_detect",
@@ -929,6 +935,110 @@ static int adf4377_freq_change(struct notifier_block *nb, unsigned long action,
 	return NOTIFY_OK;
 }
 
+static unsigned long adf4377_clk_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	struct adf4377_state *st = to_adf4377_state(hw);
+	u64 freq;
+	int ret;
+
+	ret = adf4377_get_freq(st, &freq);
+	if (ret)
+		return 0;
+
+	return freq;
+}
+
+static int adf4377_clk_set_rate(struct clk_hw *hw,
+				unsigned long rate,
+				unsigned long parent_rate)
+{
+	struct adf4377_state *st = to_adf4377_state(hw);
+
+	return adf4377_set_freq(st, rate);
+}
+
+static int adf4377_clk_prepare(struct clk_hw *hw)
+{
+	struct adf4377_state *st = to_adf4377_state(hw);
+
+	return regmap_update_bits(st->regmap, 0x1a, ADF4377_001A_PD_CLKOUT1_MSK |
+				  ADF4377_001A_PD_CLKOUT2_MSK,
+				  FIELD_PREP(ADF4377_001A_PD_CLKOUT1_MSK, 0) |
+				  FIELD_PREP(ADF4377_001A_PD_CLKOUT2_MSK, 0));
+}
+
+static void adf4377_clk_unprepare(struct clk_hw *hw)
+{
+	struct adf4377_state *st = to_adf4377_state(hw);
+
+	regmap_update_bits(st->regmap, 0x1a, ADF4377_001A_PD_CLKOUT1_MSK |
+			   ADF4377_001A_PD_CLKOUT2_MSK,
+			   FIELD_PREP(ADF4377_001A_PD_CLKOUT1_MSK, 1) |
+			   FIELD_PREP(ADF4377_001A_PD_CLKOUT2_MSK, 1));
+}
+
+static int adf4377_clk_is_prepared(struct clk_hw *hw)
+{
+	struct adf4377_state *st = to_adf4377_state(hw);
+	unsigned int readval;
+	int ret;
+
+	ret = regmap_read(st->regmap, 0x1a, &readval);
+	if (ret)
+		return ret;
+
+	return !(readval & (ADF4377_001A_PD_CLKOUT1_MSK | ADF4377_001A_PD_CLKOUT2_MSK));
+}
+
+static const struct clk_ops adf4377_clk_ops = {
+	.recalc_rate = adf4377_clk_recalc_rate,
+	.set_rate = adf4377_clk_set_rate,
+	.prepare = adf4377_clk_prepare,
+	.unprepare = adf4377_clk_unprepare,
+	.is_prepared = adf4377_clk_is_prepared,
+};
+
+static int adf4377_clk_register(struct adf4377_state *st)
+{
+	struct spi_device *spi = st->spi;
+	struct device *dev = &spi->dev;
+	struct clk_init_data init;
+	struct clk_parent_data parent_data;
+	int ret;
+
+	if (!device_property_present(dev, "#clock-cells"))
+		return 0;
+
+	ret = device_property_read_string(dev, "clock-output-names", &init.name);
+	if (ret) {
+		init.name = devm_kasprintf(dev, GFP_KERNEL, "%pfw-clk",
+					   dev_fwnode(dev));
+		if (!init.name)
+			return -ENOMEM;
+	}
+
+	parent_data.fw_name = "ref_in";
+
+	init.ops = &adf4377_clk_ops;
+	init.parent_data = &parent_data;
+	init.num_parents = 1;
+	init.flags = CLK_SET_RATE_PARENT;
+
+	st->hw.init = &init;
+	ret = devm_clk_hw_register(dev, &st->hw);
+	if (ret)
+		return ret;
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, &st->hw);
+	if (ret)
+		return ret;
+
+	st->clkout = st->hw.clk;
+
+	return 0;
+}
+
 static const struct adf4377_chip_info adf4377_chip_info = {
 	.name = "adf4377",
 	.has_gpio_enclk2 = true,
@@ -958,8 +1068,6 @@ static int adf4377_probe(struct spi_device *spi)
 
 	indio_dev->info = &adf4377_info;
 	indio_dev->name = "adf4377";
-	indio_dev->channels = adf4377_channels;
-	indio_dev->num_channels = ARRAY_SIZE(adf4377_channels);
 
 	st->regmap = regmap;
 	st->spi = spi;
@@ -979,6 +1087,15 @@ static int adf4377_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
+	ret = adf4377_clk_register(st);
+	if (ret)
+		return ret;
+
+	if (!st->clkout) {
+		indio_dev->channels = adf4377_channels;
+		indio_dev->num_channels = ARRAY_SIZE(adf4377_channels);
+	}
+
 	return devm_iio_device_register(&spi->dev, indio_dev);
 }
 
-- 
2.43.0