[PATCH v5 2/2] iio: frequency: adf4350: add clk provider

[Antoniu Miclaus]

Add clk provider feature for the adf4350.

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@xxxxxxxxxx>
---
changes in v5:
 - add error handling for dt properties parse.
 - drop all IIO channels if driver acts as clock provider.
 drivers/iio/frequency/adf4350.c | 129 +++++++++++++++++++++++++++++++-
 1 file changed, 127 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/frequency/adf4350.c b/drivers/iio/frequency/adf4350.c
index 4abf80f75ef5..d0791a21e65c 100644
--- a/drivers/iio/frequency/adf4350.c
+++ b/drivers/iio/frequency/adf4350.c
@@ -19,6 +19,7 @@
 #include <linux/gpio/consumer.h>
 #include <asm/div64.h>
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -36,6 +37,9 @@ struct adf4350_state {
 	struct gpio_desc		*lock_detect_gpiod;
 	struct adf4350_platform_data	*pdata;
 	struct clk			*clk;
+	struct clk			*clkout;
+	const char			*clk_out_name;
+	struct clk_hw			hw;
 	unsigned long			clkin;
 	unsigned long			chspc; /* Channel Spacing */
 	unsigned long			fpfd; /* Phase Frequency Detector */
@@ -61,6 +65,8 @@ struct adf4350_state {
 	__be32				val __aligned(IIO_DMA_MINALIGN);
 };
 
+#define to_adf4350_state(_hw) container_of(_hw, struct adf4350_state, hw)
+
 static struct adf4350_platform_data default_pdata = {
 	.channel_spacing = 10000,
 	.r2_user_settings = ADF4350_REG2_PD_POLARITY_POS |
@@ -381,6 +387,115 @@ static const struct iio_info adf4350_info = {
 	.debugfs_reg_access = &adf4350_reg_access,
 };
 
+static void adf4350_clk_del_provider(void *data)
+{
+	struct adf4350_state *st = data;
+
+	of_clk_del_provider(st->spi->dev.of_node);
+}
+
+static unsigned long adf4350_clk_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	struct adf4350_state *st = to_adf4350_state(hw);
+	unsigned long long tmp;
+
+	tmp = (u64)(st->r0_int * st->r1_mod + st->r0_fract) * st->fpfd;
+	do_div(tmp, st->r1_mod * (1 << st->r4_rf_div_sel));
+
+	return tmp;
+}
+
+static int adf4350_clk_set_rate(struct clk_hw *hw,
+				unsigned long rate,
+				unsigned long parent_rate)
+{
+	struct adf4350_state *st = to_adf4350_state(hw);
+
+	if (parent_rate == 0 || parent_rate > ADF4350_MAX_FREQ_REFIN)
+		return -EINVAL;
+
+	st->clkin = parent_rate;
+
+	return adf4350_set_freq(st, rate);
+}
+
+static int adf4350_clk_prepare(struct clk_hw *hw)
+{
+	struct adf4350_state *st = to_adf4350_state(hw);
+
+	st->regs[ADF4350_REG2] &= ~ADF4350_REG2_POWER_DOWN_EN;
+
+	return adf4350_sync_config(st);
+}
+
+static void adf4350_clk_unprepare(struct clk_hw *hw)
+{
+	struct adf4350_state *st = to_adf4350_state(hw);
+
+	st->regs[ADF4350_REG2] |= ADF4350_REG2_POWER_DOWN_EN;
+
+	adf4350_sync_config(st);
+}
+
+static int adf4350_clk_is_enabled(struct clk_hw *hw)
+{
+	struct adf4350_state *st = to_adf4350_state(hw);
+
+	return (st->regs[ADF4350_REG2] & ADF4350_REG2_POWER_DOWN_EN);
+}
+
+static const struct clk_ops adf4350_clk_ops = {
+	.recalc_rate = adf4350_clk_recalc_rate,
+	.set_rate = adf4350_clk_set_rate,
+	.prepare = adf4350_clk_prepare,
+	.unprepare = adf4350_clk_unprepare,
+	.is_enabled = adf4350_clk_is_enabled,
+};
+
+static int adf4350_clk_register(struct adf4350_state *st)
+{
+	struct spi_device *spi = st->spi;
+	struct clk_init_data init;
+	struct clk *clk;
+	const char *parent_name;
+	int ret;
+
+	if (!device_property_present(&spi->dev, "#clock-cells"))
+		return 0;
+
+	init.name = devm_kasprintf(&spi->dev, GFP_KERNEL, "%s-clk",
+				   fwnode_get_name(dev_fwnode(&spi->dev)));
+	if (!init.name)
+		return -ENOMEM;
+
+	if (device_property_read_string(&spi->dev, "clock-output-names",
+					&init.name))
+		init.name = spi->dev.of_node->name;
+
+	parent_name = of_clk_get_parent_name(spi->dev.of_node, 0);
+	if (!parent_name)
+		return -EINVAL;
+
+	init.ops = &adf4350_clk_ops;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+	init.flags = CLK_SET_RATE_PARENT;
+
+	st->hw.init = &init;
+	clk = devm_clk_register(&spi->dev, &st->hw);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	ret = of_clk_add_provider(spi->dev.of_node, of_clk_src_simple_get, clk);
+	if (ret)
+		return ret;
+
+	st->clkout = clk;
+
+	return devm_add_action_or_reset(&spi->dev, adf4350_clk_del_provider, st);
+}
+
 static struct adf4350_platform_data *adf4350_parse_dt(struct device *dev)
 {
 	struct adf4350_platform_data *pdata;
@@ -522,8 +637,6 @@ static int adf4350_probe(struct spi_device *spi)
 
 	indio_dev->info = &adf4350_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
-	indio_dev->channels = &adf4350_chan;
-	indio_dev->num_channels = 1;
 
 	mutex_init(&st->lock);
 
@@ -551,6 +664,18 @@ static int adf4350_probe(struct spi_device *spi)
 			return ret;
 	}
 
+	ret = adf4350_clk_register(st);
+	if (ret)
+		return ret;
+
+	if (st->clkout) {
+		indio_dev->channels = NULL;
+		indio_dev->num_channels = 0;
+	} else {
+		indio_dev->channels = &adf4350_chan;
+		indio_dev->num_channels = 1;
+	}
+
 	ret = devm_add_action_or_reset(&spi->dev, adf4350_power_down, indio_dev);
 	if (ret)
 		return dev_err_probe(&spi->dev, ret,
-- 
2.45.2