[PATCH 1/2] ALSA: ac97: add bus binding for codecs

[PATCH 1/2] ALSA: ac97: add bus binding for codecs

[Robert Jarzmik]

Add the generic ac97 bus binding, especially for ac97 codecs discovered
by ac97 hardware probing.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 .../devicetree/bindings/sound/ac97-bus.txt         | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sound/ac97-bus.txt

diff --git a/Documentation/devicetree/bindings/sound/ac97-bus.txt b/Documentation/devicetree/bindings/sound/ac97-bus.txt
new file mode 100644
index 000000000000..103c428f2595
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/ac97-bus.txt
@@ -0,0 +1,32 @@
+Generic AC97 Device Properties
+
+This documents describes the devicetree bindings for an ac97 controller child
+node describing ac97 codecs.
+
+Required properties:
+-compatible : Must be "ac97,vendor_id1,vendor_id2
+	      The ids shall be the 4 characters hexadecimal encoding, such as
+	      given by "%04x" formatting of printf
+-reg	    : Must be the ac97 codec number, between 0 and 3
+
+Example:
+ac97: sound@40500000 {
+	compatible = "marvell,pxa270-ac97";
+	reg = < 0x40500000 0x1000 >;
+	interrupts = <14>;
+	reset-gpios = <&gpio 95 GPIO_ACTIVE_HIGH>;
+	#sound-dai-cells = <1>;
+	pinctrl-names = "default";
+	pinctrl-0 = < &pinctrl_ac97_default >;
+	clocks = <&clks CLK_AC97>, <&clks CLK_AC97CONF>;
+	clock-names = "AC97CLK", "AC97CONFCLK";
+
+	#address-cells = <1>;
+	#size-cells = <0>;
+	audio-codec@0 {
+		reg = <0>;
+		compatible = "ac97,574d,4c13";
+		clocks = <&fixed_wm9713_clock>;
+		clock-names = "ac97_clk";
+	}
+};
-- 
2.11.0

[PATCH 2/2] ALSA: ac97: add codecs devicetree binding

[Robert Jarzmik]

Add a devicetree binding for codecs. This is especially useful if the
AC97 bitclk clock is provided by the codec, as it has to be described in
the devicetree description for the ac97 bus code to aquire it.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
Special review query: review the "return of_node_get(node)", which
assumes that upon device removal, of_put_node(dev.of_node) will be
called...
---
 sound/ac97/bus.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/sound/ac97/bus.c b/sound/ac97/bus.c
index 31f858eceffc..c8e20dd8786f 100644
--- a/sound/ac97/bus.c
+++ b/sound/ac97/bus.c
@@ -13,6 +13,7 @@
 #include <linux/idr.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
+#include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
@@ -68,6 +69,27 @@ ac97_codec_find(struct ac97_controller *ac97_ctrl, unsigned int codec_num)
 	return ac97_ctrl->codecs[codec_num];
 }
 
+static struct device_node *
+ac97_of_get_child_device(struct ac97_controller *ac97_ctrl, int idx,
+			 unsigned int vendor_id)
+{
+	struct device_node *node;
+	u32 reg;
+	char compat[] = "ac97,0000,0000";
+
+	snprintf(compat, sizeof(compat), "ac97,%04x,%04x",
+		 vendor_id >> 16, vendor_id & 0xffff);
+
+	for_each_child_of_node(ac97_ctrl->parent->of_node, node) {
+		if ((idx != of_property_read_u32(node, "reg", &reg)) ||
+		    !of_device_is_compatible(node, compat))
+			continue;
+		return of_node_get(node);
+	}
+
+	return NULL;
+}
+
 static void ac97_codec_release(struct device *dev)
 {
 	struct ac97_codec_device *adev;
@@ -98,6 +120,8 @@ static int ac97_codec_add(struct ac97_controller *ac97_ctrl, int idx,
 
 	device_initialize(&codec->dev);
 	dev_set_name(&codec->dev, "%s:%u", dev_name(ac97_ctrl->parent), idx);
+	codec->dev.of_node = ac97_of_get_child_device(ac97_ctrl, idx,
+						      vendor_id);
 
 	ret = device_add(&codec->dev);
 	if (ret)
-- 
2.11.0

Re: [PATCH 2/2] ALSA: ac97: add codecs devicetree binding

[Takashi Iwai]

On Thu, 21 Jun 2018 17:43:56 +0200,
Robert Jarzmik wrote:
> 
> Add a devicetree binding for codecs. This is especially useful if the
> AC97 bitclk clock is provided by the codec, as it has to be described in
> the devicetree description for the ac97 bus code to aquire it.
> 
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> ---
> Special review query: review the "return of_node_get(node)", which
> assumes that upon device removal, of_put_node(dev.of_node) will be
> called...

Is it really done automagically?  I couldn't spot it.


thanks,

Takashi

Re: [PATCH 2/2] ALSA: ac97: add codecs devicetree binding

[Robert Jarzmik]

Takashi Iwai <tiwai@suse.de> writes:

>> Special review query: review the "return of_node_get(node)", which
>> assumes that upon device removal, of_put_node(dev.of_node) will be
>> called...
>
> Is it really done automagically?  I couldn't spot it.
Neither could I ...

I based this on device_set_of_node_from_dev(), and the it "seemed" logical to me
that a device probed from devicetree would take a refcnt on the devicetree node.

As the "logical" conflicted with my search for the automagical of_node_get(), I
need the special review query.

Cheers.

-- 
Robert

Re: [PATCH 2/2] ALSA: ac97: add codecs devicetree binding

[Takashi Iwai]

On Fri, 22 Jun 2018 12:41:14 +0200,
Robert Jarzmik wrote:
> 
> Takashi Iwai <tiwai@suse.de> writes:
> 
> >> Special review query: review the "return of_node_get(node)", which
> >> assumes that upon device removal, of_put_node(dev.of_node) will be
> >> called...
> >
> > Is it really done automagically?  I couldn't spot it.
> Neither could I ...
> 
> I based this on device_set_of_node_from_dev(), and the it "seemed" logical to me
> that a device probed from devicetree would take a refcnt on the devicetree node.
> 
> As the "logical" conflicted with my search for the automagical of_node_get(), I
> need the special review query.

Hm, some of these users (e.g. drivers/usb/core/*) do call
of_node_put() properly at releasing, but some look leaking to me.
I don't think we have the common code in the driver core to release
dev->of_node, at least.

If any, this should be done in ac97_codec_release(), I suppose.


Takashi

Re: [PATCH 2/2] ALSA: ac97: add codecs devicetree binding

[Mark Brown]

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On Fri, Jun 22, 2018 at 12:49:49PM +0200, Takashi Iwai wrote:

> Hm, some of these users (e.g. drivers/usb/core/*) do call
> of_node_put() properly at releasing, but some look leaking to me.
> I don't think we have the common code in the driver core to release
> dev->of_node, at least.

> If any, this should be done in ac97_codec_release(), I suppose.

Yeah, I'd expect this to be handled in each bus.

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