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-rw-r--r--Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt1
-rw-r--r--Documentation/devicetree/bindings/sound/ics43432.txt6
-rw-r--r--Documentation/devicetree/bindings/sound/mt8195-afe-pcm.yaml184
-rw-r--r--Documentation/devicetree/bindings/sound/mt8195-mt6359-rt1019-rt5682.yaml47
-rw-r--r--Documentation/devicetree/bindings/sound/realtek,rt1015p.yaml4
-rw-r--r--Documentation/devicetree/bindings/sound/renesas,rz-ssi.yaml118
-rw-r--r--Documentation/devicetree/bindings/sound/rockchip-i2s.yaml11
-rw-r--r--Documentation/devicetree/bindings/sound/rockchip-spdif.yaml1
-rw-r--r--Documentation/devicetree/bindings/vendor-prefixes.yaml2
-rw-r--r--Documentation/sound/alsa-configuration.rst34
-rw-r--r--Documentation/sound/hd-audio/notes.rst11
-rw-r--r--Documentation/sound/kernel-api/writing-an-alsa-driver.rst33
12 files changed, 447 insertions, 5 deletions
diff --git a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
index c483dcec01f8..bd863bd69501 100644
--- a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
+++ b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
@@ -6,6 +6,7 @@ Required properties:
"ti,da830-mcasp-audio" : for both DA830 & DA850 platforms
"ti,am33xx-mcasp-audio" : for AM33xx platforms (AM33xx, AM43xx, TI81xx)
"ti,dra7-mcasp-audio" : for DRA7xx platforms
+ "ti,omap4-mcasp-audio" : for OMAP4
- reg : Should contain reg specifiers for the entries in the reg-names property.
- reg-names : Should contain:
diff --git a/Documentation/devicetree/bindings/sound/ics43432.txt b/Documentation/devicetree/bindings/sound/ics43432.txt
index b02e3a6c0fef..e6f05f2f6c4e 100644
--- a/Documentation/devicetree/bindings/sound/ics43432.txt
+++ b/Documentation/devicetree/bindings/sound/ics43432.txt
@@ -1,4 +1,4 @@
-Invensense ICS-43432 MEMS microphone with I2S output.
+Invensense ICS-43432-compatible MEMS microphone with I2S output.
There are no software configuration options for this device, indeed, the only
host connection is the I2S interface. Apart from requirements on clock
@@ -8,7 +8,9 @@ contain audio data. A hardware pin determines if the device outputs data
on the left or right channel of the I2S frame.
Required properties:
- - compatible : Must be "invensense,ics43432"
+ - compatible: should be one of the following.
+ "invensense,ics43432": For the Invensense ICS43432
+ "cui,cmm-4030d-261": For the CUI CMM-4030D-261-I2S-TR
Example:
diff --git a/Documentation/devicetree/bindings/sound/mt8195-afe-pcm.yaml b/Documentation/devicetree/bindings/sound/mt8195-afe-pcm.yaml
new file mode 100644
index 000000000000..53e9434a6d9d
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/mt8195-afe-pcm.yaml
@@ -0,0 +1,184 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/mt8195-afe-pcm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Mediatek AFE PCM controller for mt8195
+
+maintainers:
+ - Trevor Wu <trevor.wu@mediatek.com>
+
+properties:
+ compatible:
+ const: mediatek,mt8195-audio
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ mediatek,topckgen:
+ $ref: "/schemas/types.yaml#/definitions/phandle"
+ description: The phandle of the mediatek topckgen controller
+
+ power-domains:
+ maxItems: 1
+
+ clocks:
+ items:
+ - description: 26M clock
+ - description: audio pll1 clock
+ - description: audio pll2 clock
+ - description: clock divider for i2si1_mck
+ - description: clock divider for i2si2_mck
+ - description: clock divider for i2so1_mck
+ - description: clock divider for i2so2_mck
+ - description: clock divider for dptx_mck
+ - description: a1sys hoping clock
+ - description: audio intbus clock
+ - description: audio hires clock
+ - description: audio local bus clock
+ - description: mux for dptx_mck
+ - description: mux for i2so1_mck
+ - description: mux for i2so2_mck
+ - description: mux for i2si1_mck
+ - description: mux for i2si2_mck
+ - description: audio infra 26M clock
+ - description: infra bus clock
+
+ clock-names:
+ items:
+ - const: clk26m
+ - const: apll1_ck
+ - const: apll2_ck
+ - const: apll12_div0
+ - const: apll12_div1
+ - const: apll12_div2
+ - const: apll12_div3
+ - const: apll12_div9
+ - const: a1sys_hp_sel
+ - const: aud_intbus_sel
+ - const: audio_h_sel
+ - const: audio_local_bus_sel
+ - const: dptx_m_sel
+ - const: i2so1_m_sel
+ - const: i2so2_m_sel
+ - const: i2si1_m_sel
+ - const: i2si2_m_sel
+ - const: infra_ao_audio_26m_b
+ - const: scp_adsp_audiodsp
+
+ mediatek,etdm-in1-chn-disabled:
+ $ref: /schemas/types.yaml#/definitions/uint8-array
+ maxItems: 24
+ description: Specify which input channel should be disabled.
+
+ mediatek,etdm-in2-chn-disabled:
+ $ref: /schemas/types.yaml#/definitions/uint8-array
+ maxItems: 16
+ description: Specify which input channel should be disabled.
+
+patternProperties:
+ "^mediatek,etdm-in[1-2]-mclk-always-on-rate-hz$":
+ description: Specify etdm in mclk output rate for always on case.
+
+ "^mediatek,etdm-out[1-3]-mclk-always-on-rate-hz$":
+ description: Specify etdm out mclk output rate for always on case.
+
+ "^mediatek,etdm-in[1-2]-multi-pin-mode$":
+ type: boolean
+ description: if present, the etdm data mode is I2S.
+
+ "^mediatek,etdm-out[1-3]-multi-pin-mode$":
+ type: boolean
+ description: if present, the etdm data mode is I2S.
+
+ "^mediatek,etdm-in[1-2]-cowork-source$":
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ etdm modules can share the same external clock pin. Specify
+ which etdm clock source is required by this etdm in moudule.
+ enum:
+ - 0 # etdm1_in
+ - 1 # etdm2_in
+ - 2 # etdm1_out
+ - 3 # etdm2_out
+
+ "^mediatek,etdm-out[1-2]-cowork-source$":
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ etdm modules can share the same external clock pin. Specify
+ which etdm clock source is required by this etdm out moudule.
+ enum:
+ - 0 # etdm1_in
+ - 1 # etdm2_in
+ - 2 # etdm1_out
+ - 3 # etdm2_out
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - mediatek,topckgen
+ - power-domains
+ - clocks
+ - clock-names
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/clock/mt8195-clk.h>
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+ #include <dt-bindings/interrupt-controller/irq.h>
+ #include <dt-bindings/power/mt8195-power.h>
+
+ afe: mt8195-afe-pcm@10890000 {
+ compatible = "mediatek,mt8195-audio";
+ reg = <0x10890000 0x10000>;
+ interrupts = <GIC_SPI 822 IRQ_TYPE_LEVEL_HIGH 0>;
+ mediatek,topckgen = <&topckgen>;
+ power-domains = <&spm MT8195_POWER_DOMAIN_AUDIO>;
+ clocks = <&clk26m>,
+ <&topckgen CLK_TOP_APLL1>,
+ <&topckgen CLK_TOP_APLL2>,
+ <&topckgen CLK_TOP_APLL12_DIV0>,
+ <&topckgen CLK_TOP_APLL12_DIV1>,
+ <&topckgen CLK_TOP_APLL12_DIV2>,
+ <&topckgen CLK_TOP_APLL12_DIV3>,
+ <&topckgen CLK_TOP_APLL12_DIV9>,
+ <&topckgen CLK_TOP_A1SYS_HP_SEL>,
+ <&topckgen CLK_TOP_AUD_INTBUS_SEL>,
+ <&topckgen CLK_TOP_AUDIO_H_SEL>,
+ <&topckgen CLK_TOP_AUDIO_LOCAL_BUS_SEL>,
+ <&topckgen CLK_TOP_DPTX_M_SEL>,
+ <&topckgen CLK_TOP_I2SO1_M_SEL>,
+ <&topckgen CLK_TOP_I2SO2_M_SEL>,
+ <&topckgen CLK_TOP_I2SI1_M_SEL>,
+ <&topckgen CLK_TOP_I2SI2_M_SEL>,
+ <&infracfg_ao CLK_INFRA_AO_AUDIO_26M_B>,
+ <&scp_adsp CLK_SCP_ADSP_AUDIODSP>;
+ clock-names = "clk26m",
+ "apll1_ck",
+ "apll2_ck",
+ "apll12_div0",
+ "apll12_div1",
+ "apll12_div2",
+ "apll12_div3",
+ "apll12_div9",
+ "a1sys_hp_sel",
+ "aud_intbus_sel",
+ "audio_h_sel",
+ "audio_local_bus_sel",
+ "dptx_m_sel",
+ "i2so1_m_sel",
+ "i2so2_m_sel",
+ "i2si1_m_sel",
+ "i2si2_m_sel",
+ "infra_ao_audio_26m_b",
+ "scp_adsp_audiodsp";
+ };
+
+...
diff --git a/Documentation/devicetree/bindings/sound/mt8195-mt6359-rt1019-rt5682.yaml b/Documentation/devicetree/bindings/sound/mt8195-mt6359-rt1019-rt5682.yaml
new file mode 100644
index 000000000000..20bc0ffd0e34
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/mt8195-mt6359-rt1019-rt5682.yaml
@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/mt8195-mt6359-rt1019-rt5682.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Mediatek MT8195 with MT6359, RT1019 and RT5682 ASoC sound card driver
+
+maintainers:
+ - Trevor Wu <trevor.wu@mediatek.com>
+
+description:
+ This binding describes the MT8195 sound card.
+
+properties:
+ compatible:
+ const: mediatek,mt8195_mt6359_rt1019_rt5682
+
+ mediatek,platform:
+ $ref: "/schemas/types.yaml#/definitions/phandle"
+ description: The phandle of MT8195 ASoC platform.
+
+ mediatek,dptx-codec:
+ $ref: "/schemas/types.yaml#/definitions/phandle"
+ description: The phandle of MT8195 Display Port Tx codec node.
+
+ mediatek,hdmi-codec:
+ $ref: "/schemas/types.yaml#/definitions/phandle"
+ description: The phandle of MT8195 HDMI codec node.
+
+additionalProperties: false
+
+required:
+ - compatible
+ - mediatek,platform
+
+examples:
+ - |
+
+ sound: mt8195-sound {
+ compatible = "mediatek,mt8195_mt6359_rt1019_rt5682";
+ mediatek,platform = <&afe>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&aud_pins_default>;
+ };
+
+...
diff --git a/Documentation/devicetree/bindings/sound/realtek,rt1015p.yaml b/Documentation/devicetree/bindings/sound/realtek,rt1015p.yaml
index 644b68edf3e1..fdb7f295ef2d 100644
--- a/Documentation/devicetree/bindings/sound/realtek,rt1015p.yaml
+++ b/Documentation/devicetree/bindings/sound/realtek,rt1015p.yaml
@@ -15,7 +15,9 @@ description: |
properties:
compatible:
- const: realtek,rt1015p
+ enum:
+ - realtek,rt1015p
+ - realtek,rt1019p
sdb-gpios:
description:
diff --git a/Documentation/devicetree/bindings/sound/renesas,rz-ssi.yaml b/Documentation/devicetree/bindings/sound/renesas,rz-ssi.yaml
new file mode 100644
index 000000000000..414ff8035a4e
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/renesas,rz-ssi.yaml
@@ -0,0 +1,118 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/renesas,rz-ssi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/G2L ASoC Sound Serial Interface (SSIF-2)
+
+maintainers:
+ - Biju Das <biju.das.jz@bp.renesas.com>
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - renesas,r9a07g044-ssi # RZ/G2{L,LC}
+ - const: renesas,rz-ssi
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 4
+
+ interrupt-names:
+ items:
+ - const: int_req
+ - const: dma_rx
+ - const: dma_tx
+ - const: dma_rt
+
+ clocks:
+ maxItems: 4
+
+ clock-names:
+ items:
+ - const: ssi
+ - const: ssi_sfr
+ - const: audio_clk1
+ - const: audio_clk2
+
+ power-domains:
+ maxItems: 1
+
+ resets:
+ maxItems: 1
+
+ dmas:
+ minItems: 1
+ maxItems: 2
+ description:
+ The first cell represents a phandle to dmac
+ The second cell specifies the encoded MID/RID values of the SSI port
+ connected to the DMA client and the slave channel configuration
+ parameters.
+ bits[0:9] - Specifies MID/RID value of a SSI channel as below
+ MID/RID value of SSI rx0 = 0x256
+ MID/RID value of SSI tx0 = 0x255
+ MID/RID value of SSI rx1 = 0x25a
+ MID/RID value of SSI tx1 = 0x259
+ MID/RID value of SSI rt2 = 0x25f
+ MID/RID value of SSI rx3 = 0x262
+ MID/RID value of SSI tx3 = 0x261
+ bit[10] - HIEN = 1, Detects a request in response to the rising edge
+ of the signal
+ bit[11] - LVL = 0, Detects based on the edge
+ bits[12:14] - AM = 2, Bus cycle mode
+ bit[15] - TM = 0, Single transfer mode
+
+ dma-names:
+ oneOf:
+ - items:
+ - const: tx
+ - const: rx
+ - items:
+ - const: rt
+
+ '#sound-dai-cells':
+ const: 0
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - interrupt-names
+ - clocks
+ - clock-names
+ - resets
+ - '#sound-dai-cells'
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+ #include <dt-bindings/clock/r9a07g044-cpg.h>
+
+ ssi0: ssi@10049c00 {
+ compatible = "renesas,r9a07g044-ssi",
+ "renesas,rz-ssi";
+ reg = <0x10049c00 0x400>;
+ interrupts = <GIC_SPI 326 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 327 IRQ_TYPE_EDGE_RISING>,
+ <GIC_SPI 328 IRQ_TYPE_EDGE_RISING>,
+ <GIC_SPI 329 IRQ_TYPE_EDGE_RISING>;
+ interrupt-names = "int_req", "dma_rx", "dma_tx", "dma_rt";
+ clocks = <&cpg CPG_MOD R9A07G044_SSI0_PCLK2>,
+ <&cpg CPG_MOD R9A07G044_SSI0_PCLK_SFR>,
+ <&audio_clk1>,
+ <&audio_clk2>;
+ clock-names = "ssi", "ssi_sfr", "audio_clk1", "audio_clk2";
+ power-domains = <&cpg>;
+ resets = <&cpg R9A07G044_SSI0_RST_M2_REG>;
+ dmas = <&dmac 0x2655>,
+ <&dmac 0x2656>;
+ dma-names = "tx", "rx";
+ #sound-dai-cells = <0>;
+ };
diff --git a/Documentation/devicetree/bindings/sound/rockchip-i2s.yaml b/Documentation/devicetree/bindings/sound/rockchip-i2s.yaml
index 245895b58a2f..5ea16b8ef93f 100644
--- a/Documentation/devicetree/bindings/sound/rockchip-i2s.yaml
+++ b/Documentation/devicetree/bindings/sound/rockchip-i2s.yaml
@@ -20,7 +20,9 @@ properties:
- items:
- enum:
- rockchip,px30-i2s
+ - rockchip,rk1808-i2s
- rockchip,rk3036-i2s
+ - rockchip,rk3128-i2s
- rockchip,rk3188-i2s
- rockchip,rk3228-i2s
- rockchip,rk3288-i2s
@@ -29,6 +31,7 @@ properties:
- rockchip,rk3366-i2s
- rockchip,rk3368-i2s
- rockchip,rk3399-i2s
+ - rockchip,rv1126-i2s
- const: rockchip,rk3066-i2s
reg:
@@ -61,6 +64,14 @@ properties:
power-domains:
maxItems: 1
+ reset-names:
+ items:
+ - const: reset-m
+ - const: reset-h
+
+ resets:
+ maxItems: 2
+
rockchip,capture-channels:
$ref: /schemas/types.yaml#/definitions/uint32
default: 2
diff --git a/Documentation/devicetree/bindings/sound/rockchip-spdif.yaml b/Documentation/devicetree/bindings/sound/rockchip-spdif.yaml
index 62a61b68dfef..d0a24bf928d6 100644
--- a/Documentation/devicetree/bindings/sound/rockchip-spdif.yaml
+++ b/Documentation/devicetree/bindings/sound/rockchip-spdif.yaml
@@ -23,6 +23,7 @@ properties:
- const: rockchip,rk3366-spdif
- const: rockchip,rk3368-spdif
- const: rockchip,rk3399-spdif
+ - const: rockchip,rk3568-spdif
- items:
- enum:
- rockchip,rk3188-spdif
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index 07fb0d25fc15..ed4f66ec9a65 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -271,6 +271,8 @@ patternProperties:
description: Shenzen Chuangsiqi Technology Co.,Ltd.
"^cubietech,.*":
description: Cubietech, Ltd.
+ "^cui,.*":
+ description: CUI Devices
"^cypress,.*":
description: Cypress Semiconductor Corporation
"^cznic,.*":
diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst
index b36af65a08ed..65f61695f561 100644
--- a/Documentation/sound/alsa-configuration.rst
+++ b/Documentation/sound/alsa-configuration.rst
@@ -1059,6 +1059,12 @@ The model name ``generic`` is treated as a special case. When this
model is given, the driver uses the generic codec parser without
"codec-patch". It's sometimes good for testing and debugging.
+The model option can be used also for aliasing to another PCI or codec
+SSID. When it's passed in the form of ``model=XXXX:YYYY`` where XXXX
+and YYYY are the sub-vendor and sub-device IDs in hex numbers,
+respectively, the driver will refer to that SSID as a reference to the
+quirk table.
+
If the default configuration doesn't work and one of the above
matches with your device, report it together with alsa-info.sh
output (with ``--no-upload`` option) to kernel bugzilla or alsa-devel
@@ -2252,6 +2258,27 @@ delayed_register
The driver prints a message like "Found post-registration device
assignment: 1234abcd:04" for such a device, so that user can
notice the need.
+quirk_flags
+ Contains the bit flags for various device specific workarounds.
+ Applied to the corresponding card index.
+
+ * bit 0: Skip reading sample rate for devices
+ * bit 1: Create Media Controller API entries
+ * bit 2: Allow alignment on audio sub-slot at transfer
+ * bit 3: Add length specifier to transfers
+ * bit 4: Start playback stream at first in implement feedback mode
+ * bit 5: Skip clock selector setup
+ * bit 6: Ignore errors from clock source search
+ * bit 7: Indicates ITF-USB DSD based DACs
+ * bit 8: Add a delay of 20ms at each control message handling
+ * bit 9: Add a delay of 1-2ms at each control message handling
+ * bit 10: Add a delay of 5-6ms at each control message handling
+ * bit 11: Add a delay of 50ms at each interface setup
+ * bit 12: Perform sample rate validations at probe
+ * bit 13: Disable runtime PM autosuspend
+ * bit 14: Ignore errors for mixer access
+ * bit 15: Support generic DSD raw U32_BE format
+ * bit 16: Set up the interface at first like UAC1
This module supports multiple devices, autoprobe and hotplugging.
@@ -2261,11 +2288,14 @@ check.
NB: ``ignore_ctl_error=1`` may help when you get an error at accessing
the mixer element such as URB error -22. This happens on some
-buggy USB device or the controller.
+buggy USB device or the controller. This workaround corresponds to
+the ``quirk_flags`` bit 14, too.
-NB: quirk_alias option is provided only for testing / development.
+NB: ``quirk_alias`` option is provided only for testing / development.
If you want to have a proper support, contact to upstream for
adding the matching quirk in the driver code statically.
+Ditto for ``quirk_flags``. If a device is known to require specific
+workarounds, please report to the upstream.
Module snd-usb-caiaq
--------------------
diff --git a/Documentation/sound/hd-audio/notes.rst b/Documentation/sound/hd-audio/notes.rst
index cf4d7158af78..d118b6fe269b 100644
--- a/Documentation/sound/hd-audio/notes.rst
+++ b/Documentation/sound/hd-audio/notes.rst
@@ -215,6 +215,17 @@ There are a few special model option values:
* when ``generic`` is passed, the codec-specific parser is skipped and
only the generic parser is used.
+A new style for the model option that was introduced since 5.15 kernel
+is to pass the PCI or codec SSID in the form of ``model=XXXX:YYYY``
+where XXXX and YYYY are the sub-vendor and sub-device IDs in hex
+numbers, respectively. This is a kind of aliasing to another device;
+when this form is given, the driver will refer to that SSID as a
+reference to the quirk table. It'd be useful especially when the
+target quirk isn't listed in the model table. For example, passing
+model=103c:8862 will apply the quirk for HP ProBook 445 G8 (which
+isn't found in the model table as of writing) as long as the device is
+handled equivalently by the same driver.
+
Speaker and Headphone Output
----------------------------
diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
index 01d59b8aea92..255b7d3bebd6 100644
--- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
+++ b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
@@ -4172,6 +4172,39 @@ module license as GPL, etc., otherwise the system is shown as “tainted”.
MODULE_LICENSE("GPL");
+Device-Managed Resources
+========================
+
+In the examples above, all resources are allocated and released
+manually. But human beings are lazy in nature, especially developers
+are lazier. So there are some ways to automate the release part; it's
+the (device-)managed resources aka devres or devm family. For
+example, an object allocated via :c:func:`devm_kmalloc()` will be
+freed automatically at unbinding the device.
+
+ALSA core provides also the device-managed helper, namely,
+:c:func:`snd_devm_card_new()` for creating a card object.
+Call this functions instead of the normal :c:func:`snd_card_new()`,
+and you can forget the explicit :c:func:`snd_card_free()` call, as
+it's called automagically at error and removal paths.
+
+One caveat is that the call of :c:func:`snd_card_free()` would be put
+at the beginning of the call chain only after you call
+:c:func:`snd_card_register()`.
+
+Also, the ``private_free`` callback is always called at the card free,
+so be careful to put the hardware clean-up procedure in
+``private_free`` callback. It might be called even before you
+actually set up at an earlier error path. For avoiding such an
+invalid initialization, you can set ``private_free`` callback after
+:c:func:`snd_card_register()` call succeeds.
+
+Another thing to be remarked is that you should use device-managed
+helpers for each component as much as possible once when you manage
+the card in that way. Mixing up with the normal and the managed
+resources may screw up the release order.
+
+
How To Put Your Driver Into ALSA Tree
=====================================