[PATCH 0/3] Clean up RK3328 audio codec GPIO control

[PATCH 0/3] Clean up RK3328 audio codec GPIO control

[Robin Murphy]

Hi all,

Investigating the RK3328 GPIO_MUTE pin in the context of boards that use
it to control a regulator has highlighted that the audio codec driver
currently has some hard-coded implicit control of that pin. Fortunately
those boards don't currently enable the audio codec, because it would be
pretty terrible if playing audio changed the SD card I/O voltage. This
is a first crack at making things better.

Robin.


Robin Murphy (3):
  ASoC: dt-bindings: Make RK3328 codec GPIO explicit
  ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit
  arm64: dts: rockchip: Describe RK3328 GPIO_MUTE users

 .../bindings/sound/rockchip,rk3328-codec.txt  |  7 ++++++-
 arch/arm64/boot/dts/rockchip/rk3328-a1.dts    |  1 +
 .../arm64/boot/dts/rockchip/rk3328-rock64.dts |  1 +
 sound/soc/codecs/rk3328_codec.c               | 20 +++++--------------
 4 files changed, 13 insertions(+), 16 deletions(-)

-- 
2.17.1

[PATCH 1/3] ASoC: dt-bindings: Make RK3328 codec GPIO explicit

[Robin Murphy]

Existing RK3328 codec drivers have overloaded the GRF phandle to assume
implicit control of the limited-function GPIO_MUTE pin, which is usually
used to enable an external audio line driver IC. Since this pin has a
proper binding of its own (see gpio/rockchip,rk3328-grf-gpio.txt), make
a GPIO explicit in the codec binding too. This will help avoid ambiguity
on boards that use that pin for some other purpose.

(and while touching the example, enforce the "don't include status" rule)

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 .../devicetree/bindings/sound/rockchip,rk3328-codec.txt    | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/sound/rockchip,rk3328-codec.txt b/Documentation/devicetree/bindings/sound/rockchip,rk3328-codec.txt
index 2469588c7ccb..1ecd75d2032a 100644
--- a/Documentation/devicetree/bindings/sound/rockchip,rk3328-codec.txt
+++ b/Documentation/devicetree/bindings/sound/rockchip,rk3328-codec.txt
@@ -10,6 +10,11 @@ Required properties:
 - clock-names: should be "pclk".
 - spk-depop-time-ms: speak depop time msec.
 
+Optional properties:
+
+- mute-gpios: GPIO specifier for external line driver control (typically the
+              dedicated GPIO_MUTE pin)
+
 Example for rk3328 internal codec:
 
 codec: codec@ff410000 {
@@ -18,6 +23,6 @@ codec: codec@ff410000 {
 	rockchip,grf = <&grf>;
 	clocks = <&cru PCLK_ACODEC>;
 	clock-names = "pclk";
+	mute-gpios = <&grf_gpio 0 GPIO_ACTIVE_LOW>;
 	spk-depop-time-ms = 100;
-	status = "disabled";
 };
-- 
2.17.1

[PATCH 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Robin Murphy]

The RK3328 reference design uses an external line driver IC as a buffer
on the analog codec output, enabled by the GPIO_MUTE pin, and such a
configuration is currently assumed in the codec driver's direct poking
of GRF_SOC_CON10 to control the GPIO_MUTE output value. However, some
boards wire up analog audio yet use that pin for some other purpose, so
that assumption doesn't always hold. Update this functionality to rely
on an explicit GPIO descriptor, such that it can be managed at the
board level.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 sound/soc/codecs/rk3328_codec.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/sound/soc/codecs/rk3328_codec.c b/sound/soc/codecs/rk3328_codec.c
index 287c962ba00d..f0e9ef21c5f8 100644
--- a/sound/soc/codecs/rk3328_codec.c
+++ b/sound/soc/codecs/rk3328_codec.c
@@ -7,6 +7,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
@@ -31,7 +32,7 @@
 
 struct rk3328_codec_priv {
 	struct regmap *regmap;
-	struct regmap *grf;
+	struct gpio_desc *mute;
 	struct clk *mclk;
 	struct clk *pclk;
 	unsigned int sclk;
@@ -106,16 +107,6 @@ static int rk3328_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
 	return 0;
 }
 
-static void rk3328_analog_output(struct rk3328_codec_priv *rk3328, int mute)
-{
-	unsigned int val = BIT(17);
-
-	if (mute)
-		val |= BIT(1);
-
-	regmap_write(rk3328->grf, RK3328_GRF_SOC_CON10, val);
-}
-
 static int rk3328_digital_mute(struct snd_soc_dai *dai, int mute)
 {
 	struct rk3328_codec_priv *rk3328 =
@@ -205,7 +196,7 @@ static int rk3328_codec_open_playback(struct rk3328_codec_priv *rk3328)
 	}
 
 	msleep(rk3328->spk_depop_time);
-	rk3328_analog_output(rk3328, 1);
+	gpiod_set_value(rk3328->mute, 0);
 
 	regmap_update_bits(rk3328->regmap, HPOUTL_GAIN_CTRL,
 			   HPOUTL_GAIN_MASK, OUT_VOLUME);
@@ -246,7 +237,7 @@ static int rk3328_codec_close_playback(struct rk3328_codec_priv *rk3328)
 {
 	size_t i;
 
-	rk3328_analog_output(rk3328, 0);
+	gpiod_set_value(rk3328->mute, 1);
 
 	regmap_update_bits(rk3328->regmap, HPOUTL_GAIN_CTRL,
 			   HPOUTL_GAIN_MASK, 0);
@@ -446,7 +437,6 @@ static int rk3328_platform_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "missing 'rockchip,grf'\n");
 		return PTR_ERR(grf);
 	}
-	rk3328->grf = grf;
 	/* enable i2s_acodec_en */
 	regmap_write(grf, RK3328_GRF_SOC_CON2,
 		     (BIT(14) << 16 | BIT(14)));
@@ -458,7 +448,7 @@ static int rk3328_platform_probe(struct platform_device *pdev)
 		rk3328->spk_depop_time = 200;
 	}
 
-	rk3328_analog_output(rk3328, 0);
+	rk3328->mute = gpiod_get_optional(&pdev->dev, "mute", GPIOD_OUT_HIGH);
 
 	rk3328->mclk = devm_clk_get(&pdev->dev, "mclk");
 	if (IS_ERR(rk3328->mclk))
-- 
2.17.1

Re: [PATCH 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Mark Brown]

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On Thu, Feb 06, 2020 at 01:07:12AM +0000, Robin Murphy wrote:
> The RK3328 reference design uses an external line driver IC as a buffer
> on the analog codec output, enabled by the GPIO_MUTE pin, and such a
> configuration is currently assumed in the codec driver's direct poking
> of GRF_SOC_CON10 to control the GPIO_MUTE output value. However, some

This makes sense but it is an ABI break so is going to need
quirking for existing boards that unfortunately rely on the
existing behaviour.

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Re: [PATCH 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Robin Murphy]

On 2020-02-06 11:46 am, Mark Brown wrote:
> On Thu, Feb 06, 2020 at 01:07:12AM +0000, Robin Murphy wrote:
>> The RK3328 reference design uses an external line driver IC as a buffer
>> on the analog codec output, enabled by the GPIO_MUTE pin, and such a
>> configuration is currently assumed in the codec driver's direct poking
>> of GRF_SOC_CON10 to control the GPIO_MUTE output value. However, some
> 
> This makes sense but it is an ABI break so is going to need
> quirking for existing boards that unfortunately rely on the
> existing behaviour.

Yeah, that's where it gets tricky - there doesn't seem to be a nice way 
to differentiate between "no GPIO because old DT" and "no GPIO because 
the enable is hard-wired/irrelevant and GPIO_MUTE doesn't do what you 
think it does", and it seems really improper to introduce a DT property 
for the sole purpose of telling a Linux driver not to assume something 
it shouldn't really have in the first place.

My opinion fell on the side of a minor ABI break being the lesser of two 
evils, given that the worst case once people start enabling this codec 
on Renegade/ROC-CC boards (which I was only anticipating, but have just 
discovered is happening already[1]) results in unexpectedly stuffing 
3.3V into the SD card and SoC I/O domain while both are in 1.8V mode, 
and that the change would only really affect one other current board 
(Rock64), where most mainline users are likely to be upgrading their DTB 
in lock-step with the kernel anyway.

I guess the existing (mis)behaviour could be predicated on an 
of_machine_is_compatible() check for Rock64 boards - it's ugly, but 
should do the job if you feel it's more important to be 100% strict 
about not regressing supported systems for any possible kernel/DTB 
combination.

Thanks,
Robin.

[1] 
https://github.com/armbian/build/commit/18b24717be9639b65b86db3dbcf2b42fe73ca12c

Re: [PATCH 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Mark Brown]

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On Thu, Feb 06, 2020 at 12:36:04PM +0000, Robin Murphy wrote:
> On 2020-02-06 11:46 am, Mark Brown wrote:

> > This makes sense but it is an ABI break so is going to need
> > quirking for existing boards that unfortunately rely on the
> > existing behaviour.

> I guess the existing (mis)behaviour could be predicated on an
> of_machine_is_compatible() check for Rock64 boards - it's ugly, but should
> do the job if you feel it's more important to be 100% strict about not
> regressing supported systems for any possible kernel/DTB combination.

Yes, that's what I'm suggesting - we don't need to be exhaustive
but having an obvious place for people to put the quirk in if
they are affected is much better practice than just silently
letting things break.

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Re: [PATCH 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Peter Geis]

On Thu, Feb 6, 2020 at 8:57 AM Mark Brown <broonie@kernel.org> wrote:
>
> On Thu, Feb 06, 2020 at 12:36:04PM +0000, Robin Murphy wrote:
> > On 2020-02-06 11:46 am, Mark Brown wrote:
>
> > > This makes sense but it is an ABI break so is going to need
> > > quirking for existing boards that unfortunately rely on the
> > > existing behaviour.
>
> > I guess the existing (mis)behaviour could be predicated on an
> > of_machine_is_compatible() check for Rock64 boards - it's ugly, but should
> > do the job if you feel it's more important to be 100% strict about not
> > regressing supported systems for any possible kernel/DTB combination.
>
> Yes, that's what I'm suggesting - we don't need to be exhaustive
> but having an obvious place for people to put the quirk in if
> they are affected is much better practice than just silently
> letting things break.

Might want to put a warning in there too, so that if someone is paying
attention they will see that they are using an out of date device
tree.

[PATCH v2 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Robin Murphy]

On 2020-02-06 6:05 pm, Peter Geis wrote:
> On Thu, Feb 6, 2020 at 8:57 AM Mark Brown <broonie@kernel.org> wrote:
>>
>> On Thu, Feb 06, 2020 at 12:36:04PM +0000, Robin Murphy wrote:
>>> On 2020-02-06 11:46 am, Mark Brown wrote:
>>
>>>> This makes sense but it is an ABI break so is going to need
>>>> quirking for existing boards that unfortunately rely on the
>>>> existing behaviour.
>>
>>> I guess the existing (mis)behaviour could be predicated on an
>>> of_machine_is_compatible() check for Rock64 boards - it's ugly, but should
>>> do the job if you feel it's more important to be 100% strict about not
>>> regressing supported systems for any possible kernel/DTB combination.
>>
>> Yes, that's what I'm suggesting - we don't need to be exhaustive
>> but having an obvious place for people to put the quirk in if
>> they are affected is much better practice than just silently
>> letting things break.
> 
> Might want to put a warning in there too, so that if someone is paying
> attention they will see that they are using an out of date device
> tree.

Of course, that much is a given :)

Having thought it over some more, I reckon there's a reasonable
compromise that isn't too hideous, preserves the logical cleanup but
at least prevents audio going silent with old DTBs (plus handling GPIO
probe deferral properly which I forgot about first time around). How
does this look?

Robin.

----->8-----

The RK3328 reference design uses an external line driver IC as a buffer
on the analog codec output, enabled by the GPIO_MUTE pin, and such a
configuration is currently assumed in the codec driver's direct poking
of GRF_SOC_CON10 to control the GPIO_MUTE output value. However, some
boards wire up analog audio yet use that pin for some other purpose, so
that assumption doesn't always hold. Update this functionality to rely
on an explicit GPIO descriptor, such that it can be managed at the
board level.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 sound/soc/codecs/rk3328_codec.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/sound/soc/codecs/rk3328_codec.c b/sound/soc/codecs/rk3328_codec.c
index 287c962ba00d..115706a55577 100644
--- a/sound/soc/codecs/rk3328_codec.c
+++ b/sound/soc/codecs/rk3328_codec.c
@@ -7,6 +7,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
@@ -31,7 +32,7 @@

 struct rk3328_codec_priv {
 	struct regmap *regmap;
-	struct regmap *grf;
+	struct gpio_desc *mute;
 	struct clk *mclk;
 	struct clk *pclk;
 	unsigned int sclk;
@@ -106,16 +107,6 @@ static int rk3328_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
 	return 0;
 }

-static void rk3328_analog_output(struct rk3328_codec_priv *rk3328, int mute)
-{
-	unsigned int val = BIT(17);
-
-	if (mute)
-		val |= BIT(1);
-
-	regmap_write(rk3328->grf, RK3328_GRF_SOC_CON10, val);
-}
-
 static int rk3328_digital_mute(struct snd_soc_dai *dai, int mute)
 {
 	struct rk3328_codec_priv *rk3328 =
@@ -205,7 +196,7 @@ static int rk3328_codec_open_playback(struct rk3328_codec_priv *rk3328)
 	}

 	msleep(rk3328->spk_depop_time);
-	rk3328_analog_output(rk3328, 1);
+	gpiod_set_value(rk3328->mute, 0);

 	regmap_update_bits(rk3328->regmap, HPOUTL_GAIN_CTRL,
 			   HPOUTL_GAIN_MASK, OUT_VOLUME);
@@ -246,7 +237,7 @@ static int rk3328_codec_close_playback(struct rk3328_codec_priv *rk3328)
 {
 	size_t i;

-	rk3328_analog_output(rk3328, 0);
+	gpiod_set_value(rk3328->mute, 1);

 	regmap_update_bits(rk3328->regmap, HPOUTL_GAIN_CTRL,
 			   HPOUTL_GAIN_MASK, 0);
@@ -446,7 +437,6 @@ static int rk3328_platform_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "missing 'rockchip,grf'\n");
 		return PTR_ERR(grf);
 	}
-	rk3328->grf = grf;
 	/* enable i2s_acodec_en */
 	regmap_write(grf, RK3328_GRF_SOC_CON2,
 		     (BIT(14) << 16 | BIT(14)));
@@ -458,7 +448,18 @@ static int rk3328_platform_probe(struct platform_device *pdev)
 		rk3328->spk_depop_time = 200;
 	}

-	rk3328_analog_output(rk3328, 0);
+	rk3328->mute = gpiod_get_optional(&pdev->dev, "mute", GPIOD_OUT_HIGH);
+	if (IS_ERR(rk3328->mute))
+		return PTR_ERR(rk3328->mute);
+	/*
+	 * Rock64 is the only supported platform to have widely relied on
+	 * this; if we do happen to come across an old DTB, just leave the
+	 * external mute forced off.
+	 */
+	if (!rk3328->mute && of_machine_is_compatible("pine64,rock64")) {
+		dev_warn(&pdev->dev, "assuming implicit control of GPIO_MUTE; update devicetree if possible\n");
+		regmap_write(grf, RK3328_GRF_SOC_CON10, BIT(17) | BIT(1));
+	}

 	rk3328->mclk = devm_clk_get(&pdev->dev, "mclk");
 	if (IS_ERR(rk3328->mclk))
-- 
2.17.1

Re: [PATCH v2 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 657 bytes --]

On Thu, Feb 06, 2020 at 09:38:11PM +0000, Robin Murphy wrote:
> On 2020-02-06 6:05 pm, Peter Geis wrote:
> > On Thu, Feb 6, 2020 at 8:57 AM Mark Brown <broonie@kernel.org> wrote:
> >>


> compromise that isn't too hideous, preserves the logical cleanup but
> at least prevents audio going silent with old DTBs (plus handling GPIO
> probe deferral properly which I forgot about first time around). How
> does this look?
> 
> Robin.
> 
> ----->8-----

Please don't send revisions of individual patches in reply to discussion
of a series, it makes it really hard to follow what's going on with the
series.  Please just send patches normally.

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[PATCH 3/3] arm64: dts: rockchip: Describe RK3328 GPIO_MUTE users

[Robin Murphy]

Add explicit properties to describe existing boards' GPIO_MUTE usage
for the analog codec.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 arch/arm64/boot/dts/rockchip/rk3328-a1.dts     | 1 +
 arch/arm64/boot/dts/rockchip/rk3328-rock64.dts | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3328-a1.dts b/arch/arm64/boot/dts/rockchip/rk3328-a1.dts
index 5822cd0ee7db..6cd4543720fd 100644
--- a/arch/arm64/boot/dts/rockchip/rk3328-a1.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3328-a1.dts
@@ -60,6 +60,7 @@
 };
 
 &codec {
+	mute-gpios = <&grf_gpio 0 GPIO_ACTIVE_LOW>;
 	status = "okay";
 };
 
diff --git a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
index 62936b432f9a..bf3e546f5266 100644
--- a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
@@ -104,6 +104,7 @@
 };
 
 &codec {
+	mute-gpios = <&grf_gpio 0 GPIO_ACTIVE_LOW>;
 	status = "okay";
 
 	port@0 {
-- 
2.17.1

[PATCH v2 0/3] Clean up RK3328 audio codec GPIO control

[Robin Murphy]

Hi all,

Since nobody said anything resembling "that looks like a terrible idea!"
to what I propsed on top of v1, resending as a full v2 per Mark's
request.

Robin.


Robin Murphy (3):
  ASoC: dt-bindings: Make RK3328 codec GPIO explicit
  ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit
  arm64: dts: rockchip: Describe RK3328 GPIO_MUTE users

 .../bindings/sound/rockchip,rk3328-codec.txt  |  7 ++++-
 arch/arm64/boot/dts/rockchip/rk3328-a1.dts    |  1 +
 .../arm64/boot/dts/rockchip/rk3328-rock64.dts |  1 +
 sound/soc/codecs/rk3328_codec.c               | 31 ++++++++++---------
 4 files changed, 24 insertions(+), 16 deletions(-)

-- 
2.17.1

[PATCH v2 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Robin Murphy]

The RK3328 reference design uses an external line driver IC as a buffer
on the analog codec output, enabled by the GPIO_MUTE pin, and such a
configuration is currently assumed in the codec driver's direct poking
of GRF_SOC_CON10 to control the GPIO_MUTE output value. However, some
boards wire up analog audio yet use that pin for some other purpose, so
that assumption doesn't always hold. Update this functionality to rely
on an explicit GPIO descriptor, such that it can be managed at the
board level.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

v2:
 - add fallback case to avoid possible Rock64 regressions
 - propagate GPIO errors; "optional" doesn't really mean "ignore
   brokenness if present"

 sound/soc/codecs/rk3328_codec.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/sound/soc/codecs/rk3328_codec.c b/sound/soc/codecs/rk3328_codec.c
index 287c962ba00d..115706a55577 100644
--- a/sound/soc/codecs/rk3328_codec.c
+++ b/sound/soc/codecs/rk3328_codec.c
@@ -7,6 +7,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
@@ -31,7 +32,7 @@
 
 struct rk3328_codec_priv {
 	struct regmap *regmap;
-	struct regmap *grf;
+	struct gpio_desc *mute;
 	struct clk *mclk;
 	struct clk *pclk;
 	unsigned int sclk;
@@ -106,16 +107,6 @@ static int rk3328_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
 	return 0;
 }
 
-static void rk3328_analog_output(struct rk3328_codec_priv *rk3328, int mute)
-{
-	unsigned int val = BIT(17);
-
-	if (mute)
-		val |= BIT(1);
-
-	regmap_write(rk3328->grf, RK3328_GRF_SOC_CON10, val);
-}
-
 static int rk3328_digital_mute(struct snd_soc_dai *dai, int mute)
 {
 	struct rk3328_codec_priv *rk3328 =
@@ -205,7 +196,7 @@ static int rk3328_codec_open_playback(struct rk3328_codec_priv *rk3328)
 	}
 
 	msleep(rk3328->spk_depop_time);
-	rk3328_analog_output(rk3328, 1);
+	gpiod_set_value(rk3328->mute, 0);
 
 	regmap_update_bits(rk3328->regmap, HPOUTL_GAIN_CTRL,
 			   HPOUTL_GAIN_MASK, OUT_VOLUME);
@@ -246,7 +237,7 @@ static int rk3328_codec_close_playback(struct rk3328_codec_priv *rk3328)
 {
 	size_t i;
 
-	rk3328_analog_output(rk3328, 0);
+	gpiod_set_value(rk3328->mute, 1);
 
 	regmap_update_bits(rk3328->regmap, HPOUTL_GAIN_CTRL,
 			   HPOUTL_GAIN_MASK, 0);
@@ -446,7 +437,6 @@ static int rk3328_platform_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "missing 'rockchip,grf'\n");
 		return PTR_ERR(grf);
 	}
-	rk3328->grf = grf;
 	/* enable i2s_acodec_en */
 	regmap_write(grf, RK3328_GRF_SOC_CON2,
 		     (BIT(14) << 16 | BIT(14)));
@@ -458,7 +448,18 @@ static int rk3328_platform_probe(struct platform_device *pdev)
 		rk3328->spk_depop_time = 200;
 	}
 
-	rk3328_analog_output(rk3328, 0);
+	rk3328->mute = gpiod_get_optional(&pdev->dev, "mute", GPIOD_OUT_HIGH);
+	if (IS_ERR(rk3328->mute))
+		return PTR_ERR(rk3328->mute);
+	/*
+	 * Rock64 is the only supported platform to have widely relied on
+	 * this; if we do happen to come across an old DTB, just leave the
+	 * external mute forced off.
+	 */
+	if (!rk3328->mute && of_machine_is_compatible("pine64,rock64")) {
+		dev_warn(&pdev->dev, "assuming implicit control of GPIO_MUTE; update devicetree if possible\n");
+		regmap_write(grf, RK3328_GRF_SOC_CON10, BIT(17) | BIT(1));
+	}
 
 	rk3328->mclk = devm_clk_get(&pdev->dev, "mclk");
 	if (IS_ERR(rk3328->mclk))
-- 
2.17.1

Re: [PATCH v2 2/3] ASoC: rockchip: Make RK3328 GPIO_MUTE control explicit

[Mark Brown]

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On Tue, Feb 18, 2020 at 09:31:59PM +0000, Robin Murphy wrote:

>  - add fallback case to avoid possible Rock64 regressions

This should really have been called out in the changelog, were I reading
this cold I might've stopped at the changelog and said you needed to
keep the ABI stable for old boards.

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