[PATCH] clk: imx: Pass CCM udevice into clk_register_composite()

[Marek Vasut]

Pass the clock controller udevice into clk_register_composite(),
so it can be passed further to any registered composite clocks
and used for look up of parent clock referenced in DT "clocks"
and "clock-names" properties by phandle and name pair.

Use the clock controller udevice in imx8m_clk_mux_set_parent()
to perform accurate look up of parent clock referenced in the
CCM driver by name. If the clock name that is being looked up
matches one of the names listed in the clock controller DT node
"clock-names" array property, then the offset of the name is
looked up in the "clocks" DT property and the phandle at that
offset is resolved to the parent clock udevice. The test to
determine whether a particular driver instance registered with
clock uclass matches the parent clock is done by comparing the
OF nodes of the clock registered with clock uclass and parent
clock resolved from the phandle.

Example:

drivers/clk/imx/clk-imx8mm.c:
static const char * const imx8mm_a53_sels[] = {"osc_24m", "arm_pll_out", ...
                                      _____________|
arch/arm/dts/imx8mm.dtsi:            |
clk: clock-controller at 30380000 {     v
        clock-names = "osc_32k", "osc_24m", ...
	                           |
				   v
        clocks = <&osc_32k>, <&osc_24m>, ...
};          _______________________|
...        |
/ {        v
        osc_24m: clock-osc-24m {
                compatible = "fixed-clock";
...
};

Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Adam Ford <aford173 at gmail.com>
Cc: Christoph Niedermaier <cniedermaier at dh-electronics.com>
Cc: Dong Aisheng <aisheng.dong at nxp.com>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Michael Trimarchi <michael at amarulasolutions.com>
Cc: Peng Fan <peng.fan at nxp.com>
Cc: Sean Anderson <seanga2 at gmail.com>
Cc: Shawn Guo <shawnguo at kernel.org>
Cc: Tom Rini <trini at konsulko.com>
Cc: u-boot at lists.denx.de
---
 drivers/clk/clk-composite.c        |  2 ++
 drivers/clk/imx/clk-composite-8m.c | 30 +++++++++++++++++++++++++++++-
 include/linux/clk-provider.h       |  2 ++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
index 9e3b5191767..207224b1320 100644
--- a/drivers/clk/clk-composite.c
+++ b/drivers/clk/clk-composite.c
@@ -155,6 +155,8 @@ struct clk *clk_register_composite(struct udevice *dev, const char *name,
 		goto err;
 	}
 
+	composite->dev = dev;
+
 	if (composite->mux)
 		composite->mux->dev = clk->dev;
 	if (composite->rate)
diff --git a/drivers/clk/imx/clk-composite-8m.c b/drivers/clk/imx/clk-composite-8m.c
index 14c5b92939c..e1a3c0af308 100644
--- a/drivers/clk/imx/clk-composite-8m.c
+++ b/drivers/clk/imx/clk-composite-8m.c
@@ -116,14 +116,42 @@ static const struct clk_ops imx8m_clk_composite_divider_ops = {
 	.set_rate = imx8m_clk_composite_divider_set_rate,
 };
 
+static int imx8m_clk_mux_fetch_parent_index(struct udevice *cdev, struct clk *clk, struct clk *parent)
+{
+	struct clk_mux *mux = to_clk_mux(clk);
+	struct clk cclk;
+	int ret;
+	int i;
+
+	if (!parent)
+		return -EINVAL;
+
+	for (i = 0; i < mux->num_parents; i++) {
+		ret = clk_get_by_name(cdev, mux->parent_names[i], &cclk);
+		if (!ret && ofnode_equal(dev_ofnode(parent->dev), dev_ofnode(cclk.dev)))
+			return i;
+
+		if (!strcmp(parent->dev->name, mux->parent_names[i]))
+			return i;
+		if (!strcmp(parent->dev->name,
+			    clk_resolve_parent_clk(clk->dev,
+						   mux->parent_names[i])))
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+
 static int imx8m_clk_mux_set_parent(struct clk *clk, struct clk *parent)
 {
 	struct clk_mux *mux = to_clk_mux(clk);
+	struct clk_composite *composite = (struct clk_composite *)clk->data;
 	int index;
 	u32 val;
 	u32 reg;
 
-	index = clk_mux_fetch_parent_index(clk, parent);
+	index = imx8m_clk_mux_fetch_parent_index(composite->dev, clk, parent);
 	if (index < 0) {
 		log_err("Could not fetch index\n");
 		return index;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 5ea2171492e..267757939e0 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -219,6 +219,8 @@ struct clk_composite {
 	const struct clk_ops	*mux_ops;
 	const struct clk_ops	*rate_ops;
 	const struct clk_ops	*gate_ops;
+
+	struct udevice *dev;
 };
 
 #define to_clk_composite(_clk) container_of(_clk, struct clk_composite, clk)
-- 
2.47.2