[alsa-devel] [PATCH RFC] ARM: dts: bcm283x: Fix probing of bcm2835-i2s
Matthias Reichl
hias at horus.com
Mon Nov 20 14:18:15 CET 2017
Hi Stefan!
On Sun, Nov 19, 2017 at 06:00:27PM +0100, Stefan Wahren wrote:
> Since 517e7a1537a ("ASoC: bcm2835: move to use the clock framework")
> the bcm2835-i2s requires a clock as DT property. Unfortunately
> the necessary DT change has never been applied. While we are at it
> also fix the first PCM register range to cover the PCM_GRAY register.
>
> This patch also fixes the dt-bindings accordlingly.
>
> Signed-off-by: Stefan Wahren <stefan.wahren at i2se.com>
> ---
> Documentation/devicetree/bindings/dma/brcm,bcm2835-dma.txt | 4 ++--
> Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt | 9 ++++-----
> arch/arm/boot/dts/bcm283x.dtsi | 4 ++--
> 3 files changed, 8 insertions(+), 9 deletions(-)
>
> Hi, this is only probe tested with a RPi 1B. I don't have the sound hardware
> to test the drivers function.
>
> diff --git a/Documentation/devicetree/bindings/dma/brcm,bcm2835-dma.txt b/Documentation/devicetree/bindings/dma/brcm,bcm2835-dma.txt
> index baf9b34..b6a8cc0 100644
> --- a/Documentation/devicetree/bindings/dma/brcm,bcm2835-dma.txt
> +++ b/Documentation/devicetree/bindings/dma/brcm,bcm2835-dma.txt
> @@ -74,8 +74,8 @@ Example:
>
> bcm2835_i2s: i2s at 7e203000 {
> compatible = "brcm,bcm2835-i2s";
> - reg = < 0x7e203000 0x20>,
> - < 0x7e101098 0x02>;
> + reg = < 0x7e203000 0x24>;
> + clocks = <&clocks BCM2835_CLOCK_PCM>;
>
> dmas = <&dma 2>,
> <&dma 3>;
> diff --git a/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt b/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt
> index 65783de..7bb0362 100644
> --- a/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt
> +++ b/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt
> @@ -2,9 +2,8 @@
>
> Required properties:
> - compatible: "brcm,bcm2835-i2s"
> -- reg: A list of base address and size entries:
> - * The first entry should cover the PCM registers
> - * The second entry should cover the PCM clock registers
> +- reg: Should contain PCM registers location and length.
> +- clocks: the (PCM) clock to use
> - dmas: List of DMA controller phandle and DMA request line ordered pairs.
> - dma-names: Identifier string for each DMA request line in the dmas property.
> These strings correspond 1:1 with the ordered pairs in dmas.
> @@ -16,8 +15,8 @@ Example:
>
> bcm2835_i2s: i2s at 7e203000 {
> compatible = "brcm,bcm2835-i2s";
> - reg = <0x7e203000 0x20>,
> - <0x7e101098 0x02>;
> + reg = <0x7e203000 0x24>;
> + clocks = <&clocks BCM2835_CLOCK_PCM>;
>
> dmas = <&dma 2>,
> <&dma 3>;
> diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi
> index 431dcfc..01733a9 100644
> --- a/arch/arm/boot/dts/bcm283x.dtsi
> +++ b/arch/arm/boot/dts/bcm283x.dtsi
> @@ -391,8 +391,8 @@
>
> i2s: i2s at 7e203000 {
> compatible = "brcm,bcm2835-i2s";
> - reg = <0x7e203000 0x20>,
> - <0x7e101098 0x02>;
> + reg = <0x7e203000 0x24>;
> + clocks = <&clocks BCM2835_CLOCK_PCM>;
>
> dmas = <&dma 2>,
> <&dma 3>;
> --
Thanks a lot for fixing the DT and binding docs, the register range
and clock changes look fine to me.
While testing with a simple card DT overlay I noticed another
issue: the i2s node is missing the #sound-dai-cells property
and simple card refuses to load because of that:
[ 0.956912] OF: /sound/simple-audio-card,cpu: could not get #sound-dai-cells for /soc/i2s at 7e203000
As bcm2835-i2s has only a single DAI I think that property should
be set to 0:
diff --git a/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt b/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt
index 7bb0362828ec..7349f22bed1b 100644
--- a/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt
+++ b/Documentation/devicetree/bindings/sound/brcm,bcm2835-i2s.txt
@@ -7,6 +7,7 @@ Required properties:
- dmas: List of DMA controller phandle and DMA request line ordered pairs.
- dma-names: Identifier string for each DMA request line in the dmas property.
These strings correspond 1:1 with the ordered pairs in dmas.
+- #sound-dai-cells: Must be set to 0.
One of the DMA channels will be responsible for transmission (should be
named "tx") and one for reception (should be named "rx").
@@ -21,4 +22,5 @@ bcm2835_i2s: i2s at 7e203000 {
dmas = <&dma 2>,
<&dma 3>;
dma-names = "tx", "rx";
+ #sound-dai-cells = <0>;
};
diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi
index e08203c1d74a..bbe890d4dbb5 100644
--- a/arch/arm/boot/dts/bcm283x.dtsi
+++ b/arch/arm/boot/dts/bcm283x.dtsi
@@ -402,6 +402,7 @@
dmas = <&dma 2>,
<&dma 3>;
dma-names = "tx", "rx";
+ #sound-dai-cells = <0>;
status = "disabled";
};
With this additional change I could successfully test the following
overlay with a PCM5102 codec attached to a RPi B+:
/dts-v1/;
/plugin/;
/ {
compatible = "brcm,bcm2835";
fragment at 0 {
target = <&i2s>;
__overlay__ {
status = "okay";
};
};
fragment at 1 {
target-path = "/";
__overlay__ {
spdif_codec: spdif-transmitter {
#address-cells = <0>;
#size-cells = <0>;
#sound-dai-cells = <0>;
compatible = "linux,spdif-dit";
};
sound {
compatible = "simple-audio-card";
simple-audio-card,name = "simple";
simple-audio-card,format = "i2s";
simple-audio-card,bitclock-master = <&dailink_master>;
simple-audio-card,frame-master = <&dailink_master>;
dailink_master: simple-audio-card,cpu {
sound-dai = <&i2s>;
};
simple-audio-card,codec {
sound-dai = <&spdif_codec>;
};
};
};
};
};
BTW: this overlay will work without any hardware attached, you
just need to enable SND_SIMPLE_CARD and SND_SOC_SPDIF (which
serves as a generic codec) in your config.
so long,
Hias
More information about the Alsa-devel
mailing list