[PATCH v4 5/5] iio: adc: ad7192: Add clock provider

[Alisa-Dariana Roman <alisadariana@xxxxxxxxx>]

Internal clock of AD719X devices can be made available on MCLK2 pin. Add
clock provider to support this functionality.

Signed-off-by: Alisa-Dariana Roman <alisa.roman@xxxxxxxxxx>
---
 drivers/iio/adc/ad7192.c | 90 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index c30ffe47cd70..36e3fe50c455 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -8,6 +8,7 @@
 #include <linux/interrupt.h>
 #include <linux/bitfield.h>
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
@@ -203,6 +204,7 @@ struct ad7192_state {
 	struct regulator		*avdd;
 	struct regulator		*vref;
 	struct clk			*mclk;
+	struct clk_hw			int_clk_hw;
 	u16				int_vref_mv;
 	u32				aincom_mv;
 	u32				fclk;
@@ -403,6 +405,90 @@ static const char *const ad7192_clock_names[] = {
 	"mclk"
 };
 
+static struct ad7192_state *clk_hw_to_ad7192(struct clk_hw *hw)
+{
+	return container_of(hw, struct ad7192_state, int_clk_hw);
+}
+
+static unsigned long ad7192_clk_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	return AD7192_INT_FREQ_MHZ;
+}
+
+static int ad7192_clk_output_is_enabled(struct clk_hw *hw)
+{
+	struct ad7192_state *st = clk_hw_to_ad7192(hw);
+
+	return st->clock_sel == AD7192_CLK_INT_CO;
+}
+
+static int ad7192_clk_prepare(struct clk_hw *hw)
+{
+	struct ad7192_state *st = clk_hw_to_ad7192(hw);
+	int ret;
+
+	st->mode &= ~AD7192_MODE_CLKSRC_MASK;
+	st->mode |= AD7192_CLK_INT_CO;
+
+	ret = ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
+	if (ret)
+		return ret;
+
+	st->clock_sel = AD7192_CLK_INT_CO;
+
+	return 0;
+}
+
+static void ad7192_clk_unprepare(struct clk_hw *hw)
+{
+	struct ad7192_state *st = clk_hw_to_ad7192(hw);
+	int ret;
+
+	st->mode &= ~AD7192_MODE_CLKSRC_MASK;
+	st->mode |= AD7192_CLK_INT;
+
+	ret = ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
+	if (ret)
+		return;
+
+	st->clock_sel = AD7192_CLK_INT;
+}
+
+static const struct clk_ops ad7192_int_clk_ops = {
+	.recalc_rate = ad7192_clk_recalc_rate,
+	.is_enabled = ad7192_clk_output_is_enabled,
+	.prepare = ad7192_clk_prepare,
+	.unprepare = ad7192_clk_unprepare,
+};
+
+static int ad7192_register_clk_provider(struct ad7192_state *st)
+{
+	struct device *dev = &st->sd.spi->dev;
+	struct clk_init_data init = {};
+	const char *clk_name;
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_COMMON_CLK))
+		return 0;
+
+	ret = device_property_read_string(dev, "clock-output-names", &clk_name);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to get clock-output-names\n");
+
+	init.name = clk_name;
+	init.ops = &ad7192_int_clk_ops;
+
+	st->int_clk_hw.init = &init;
+	ret = devm_clk_hw_register(dev, &st->int_clk_hw);
+	if (ret)
+		return ret;
+
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
+					   &st->int_clk_hw);
+}
+
 static int ad7192_clock_setup(struct ad7192_state *st)
 {
 	struct device *dev = &st->sd.spi->dev;
@@ -414,6 +500,10 @@ static int ad7192_clock_setup(struct ad7192_state *st)
 	if (ret < 0) {
 		st->clock_sel = AD7192_CLK_INT;
 		st->fclk = AD7192_INT_FREQ_MHZ;
+
+		ret = ad7192_register_clk_provider(st);
+		if (ret)
+			return ret;
 	} else {
 		st->clock_sel = AD7192_CLK_EXT_MCLK1_2 + ret;
 
-- 
2.34.1