Add I2S audio support for ARC AXS10x boards

ARC AXS10x platforms consist of a mainboard with several peripherals. One of those peripherals is an HDMI output port controlled by the ADV7511 transmitter.

This patch set adds I2S audio for the AXS10x platform.

NOTE:
Although the mainline I2S driver uses ALSA DMA engine, this controller can be built without DMA support so it was necessary to add this custom platform driver so that HDMI audio works in AXS boards.

Changes v6 -> v7:
* Discard the use of memcpy
* Report IRQ_HANDLED only when there is an IRQ
* Use interrupts to check if PIO mode is in use
* Unmask interrupts only when in PIO mode
* Remove empty functions

Changes v5 -> v6:
* Use SNDRV_DMA_TYPE_CONTINUOUS

Changes v4 -> v5:
* Resolve undefined references when compiling as module
* Dropped adv7511 audio patches
* Use DMA properties in I2S to check which mode to use: PIO or DMA (as suggested by Lars-Peter Clausen)

Changes v3 -> v4:
* Reintroduced custom PCM driver (see note below)
* Use DT boolean to switch between ALSA DMA engine PCM or custom PCM
* Use fifo depth to program I2S FCR
* Update I2S documentation

Changes v2 -> v3:
* Removed pll_config functions (as suggested by Alexey Brodkin)
* Removed HDMI start at adv7511_core (as suggested by Archit Taneja)
* Use NOP functions for adv7511_audio (as suggested by Archit Taneja)
* Added adv7511_audio_exit() function (as suggested by Archit Taneja)
* Moved adv7511 to its own folder (as suggested by Archit Taneja)
* Separated file rename of adv7511_core (as suggested by Emil Velikov)
* Compile adv7511 as module if ALSA SoC is compiled as module
* Load adv7511 audio only if declared in device tree (as suggested by Laurent Pinchart)
* Dropped custom platform driver, using now ALSA DMA engine
* Dropped IRQ handler for I2S

Changes v1 -> v2:
* DT bindings moved to separate patch (as suggested by Alexey Brodkin)
* Removed defconfigs entries (as suggested by Alexey Brodkin)

Jose Abreu (4):
ASoC: dwc: Add helper functions to disable/enable irqs
ASoC: dwc: Do not use devm_clk_get() if using platform data
ASoC: dwc: Add PIO PCM extension
ASoC: dwc: Add irq parameter to DOCUMENTATION

 .../devicetree/bindings/sound/designware-i2s.txt   |   4 +
 sound/soc/dwc/Kconfig                              |   9 +
 sound/soc/dwc/Makefile                             |   5 +-
 sound/soc/dwc/designware_i2s.c                     | 229 ++++++++++-----------
 sound/soc/dwc/designware_pcm.c                     | 220 ++++++++++++++++++++
 sound/soc/dwc/local.h                              | 122 +++++++++++
 6 files changed, 467 insertions(+), 122 deletions(-)
 create mode 100644 sound/soc/dwc/designware_pcm.c
 create mode 100644 sound/soc/dwc/local.h

1.9.1


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Helper functions to disable and enable the I2S interrupts were added. Only the interrupts of the used channels are enabled.

Also, there is no need to enable irqs at dw_i2s_config(), they are already enabled at startup.

---

This patch was only introduced in v7.

 sound/soc/dwc/designware_i2s.c | 68 +++++++++++++++++++++++++-----------------
 1 file changed, 41 insertions(+), 27 deletions(-)

index 0db69b7..4c4f0dc 100644
@@ -145,26 +145,54 @@ static inline void i2s_clear_irqs(struct dw_i2s_dev *dev, u32 stream)
 	}
 }
 
-static void i2s_start(struct dw_i2s_dev *dev,
-		      struct snd_pcm_substream *substream)
+static inline void i2s_disable_irqs(struct dw_i2s_dev *dev, u32 stream,
+				    int chan_nr)
 {
-	struct i2s_clk_config_data *config = &dev->config;
 	u32 i, irq;
-	i2s_write_reg(dev->i2s_base, IER, 1);
 
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
-		for (i = 0; i < (config->chan_nr / 2); i++) {
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		for (i = 0; i < (chan_nr / 2); i++) {
+			irq = i2s_read_reg(dev->i2s_base, IMR(i));
+			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x30);
+		}
+	} else {
+		for (i = 0; i < (chan_nr / 2); i++) {
+			irq = i2s_read_reg(dev->i2s_base, IMR(i));
+			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x03);
+		}
+	}
+}
+
+static inline void i2s_enable_irqs(struct dw_i2s_dev *dev, u32 stream,
+				   int chan_nr)
+{
+	u32 i, irq;
+
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		for (i = 0; i < (chan_nr / 2); i++) {
 			irq = i2s_read_reg(dev->i2s_base, IMR(i));
 			i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x30);
 		}
-		i2s_write_reg(dev->i2s_base, ITER, 1);
 	} else {
-		for (i = 0; i < (config->chan_nr / 2); i++) {
+		for (i = 0; i < (chan_nr / 2); i++) {
 			irq = i2s_read_reg(dev->i2s_base, IMR(i));
 			i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x03);
 		}
-		i2s_write_reg(dev->i2s_base, IRER, 1);
 	}
+}
+
+static void i2s_start(struct dw_i2s_dev *dev,
+		      struct snd_pcm_substream *substream)
+{
+	struct i2s_clk_config_data *config = &dev->config;
+
+	i2s_write_reg(dev->i2s_base, IER, 1);
+	i2s_enable_irqs(dev, substream->stream, config->chan_nr);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		i2s_write_reg(dev->i2s_base, ITER, 1);
+	else
+		i2s_write_reg(dev->i2s_base, IRER, 1);
 
 	i2s_write_reg(dev->i2s_base, CER, 1);
 }

@@ -172,24 +200,14 @@ static void i2s_start(struct dw_i2s_dev *dev,
 static void i2s_stop(struct dw_i2s_dev *dev,
 		struct snd_pcm_substream *substream)
 {
-	u32 i = 0, irq;
 
 	i2s_clear_irqs(dev, substream->stream);
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		i2s_write_reg(dev->i2s_base, ITER, 0);
-
-		for (i = 0; i < 4; i++) {
-			irq = i2s_read_reg(dev->i2s_base, IMR(i));
-			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x30);
-		}
-	} else {
+	else
 		i2s_write_reg(dev->i2s_base, IRER, 0);
 
-		for (i = 0; i < 4; i++) {
-			irq = i2s_read_reg(dev->i2s_base, IMR(i));
-			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x03);
-		}
-	}
+	i2s_disable_irqs(dev, substream->stream, 8);
 
 	if (!dev->active) {
 		i2s_write_reg(dev->i2s_base, CER, 0);

@@ -223,7 +241,7 @@ static int dw_i2s_startup(struct snd_pcm_substream *substream,
 
 static void dw_i2s_config(struct dw_i2s_dev *dev, int stream)
 {
-	u32 ch_reg, irq;
+	u32 ch_reg;
 	struct i2s_clk_config_data *config = &dev->config;
 
 

@@ -235,16 +253,12 @@ static void dw_i2s_config(struct dw_i2s_dev *dev, int stream)
 				      dev->xfer_resolution);
 			i2s_write_reg(dev->i2s_base, TFCR(ch_reg),
 				      dev->fifo_th - 1);
-			irq = i2s_read_reg(dev->i2s_base, IMR(ch_reg));
-			i2s_write_reg(dev->i2s_base, IMR(ch_reg), irq & ~0x30);
 			i2s_write_reg(dev->i2s_base, TER(ch_reg), 1);
 		} else {
 			i2s_write_reg(dev->i2s_base, RCR(ch_reg),
 				      dev->xfer_resolution);
 			i2s_write_reg(dev->i2s_base, RFCR(ch_reg),
 				      dev->fifo_th - 1);
-			irq = i2s_read_reg(dev->i2s_base, IMR(ch_reg));
-			i2s_write_reg(dev->i2s_base, IMR(ch_reg), irq & ~0x03);
 			i2s_write_reg(dev->i2s_base, RER(ch_reg), 1);
 		}
 

1.9.1

The patch

ASoC: dwc: Add helper functions to disable/enable irqs

has been applied to the asoc tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark

From: Jose Abreu <[email protected]>
Date: Mon, 23 May 2016 11:02:22 +0100
Subject: [PATCH] ASoC: dwc: Add helper functions to disable/enable irqs

Helper functions to disable and enable the I2S interrupts were added. Only the interrupts of the used channels are enabled.

Also, there is no need to enable irqs at dw_i2s_config(), they are already enabled at startup.

---
 sound/soc/dwc/designware_i2s.c | 68 +++++++++++++++++++++++++-----------------
 1 file changed, 41 insertions(+), 27 deletions(-)

index 0db69b7e9617..4c4f0dc24f10 100644
@@ -145,26 +145,54 @@ static inline void i2s_clear_irqs(struct dw_i2s_dev *dev, u32 stream)
 	}
 }
 
-static void i2s_start(struct dw_i2s_dev *dev,
-		      struct snd_pcm_substream *substream)
+static inline void i2s_disable_irqs(struct dw_i2s_dev *dev, u32 stream,
+				    int chan_nr)
 {
-	struct i2s_clk_config_data *config = &dev->config;
 	u32 i, irq;
-	i2s_write_reg(dev->i2s_base, IER, 1);
 
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
-		for (i = 0; i < (config->chan_nr / 2); i++) {
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		for (i = 0; i < (chan_nr / 2); i++) {
+			irq = i2s_read_reg(dev->i2s_base, IMR(i));
+			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x30);
+		}
+	} else {
+		for (i = 0; i < (chan_nr / 2); i++) {
+			irq = i2s_read_reg(dev->i2s_base, IMR(i));
+			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x03);
+		}
+	}
+}
+
+static inline void i2s_enable_irqs(struct dw_i2s_dev *dev, u32 stream,
+				   int chan_nr)
+{
+	u32 i, irq;
+
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		for (i = 0; i < (chan_nr / 2); i++) {
 			irq = i2s_read_reg(dev->i2s_base, IMR(i));
 			i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x30);
 		}
-		i2s_write_reg(dev->i2s_base, ITER, 1);
 	} else {
-		for (i = 0; i < (config->chan_nr / 2); i++) {
+		for (i = 0; i < (chan_nr / 2); i++) {
 			irq = i2s_read_reg(dev->i2s_base, IMR(i));
 			i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x03);
 		}
-		i2s_write_reg(dev->i2s_base, IRER, 1);
 	}
+}
+
+static void i2s_start(struct dw_i2s_dev *dev,
+		      struct snd_pcm_substream *substream)
+{
+	struct i2s_clk_config_data *config = &dev->config;
+
+	i2s_write_reg(dev->i2s_base, IER, 1);
+	i2s_enable_irqs(dev, substream->stream, config->chan_nr);
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		i2s_write_reg(dev->i2s_base, ITER, 1);
+	else
+		i2s_write_reg(dev->i2s_base, IRER, 1);
 
 	i2s_write_reg(dev->i2s_base, CER, 1);
 }

@@ -172,24 +200,14 @@ static void i2s_start(struct dw_i2s_dev *dev,
 static void i2s_stop(struct dw_i2s_dev *dev,
 		struct snd_pcm_substream *substream)
 {
-	u32 i = 0, irq;
 
 	i2s_clear_irqs(dev, substream->stream);
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		i2s_write_reg(dev->i2s_base, ITER, 0);
-
-		for (i = 0; i < 4; i++) {
-			irq = i2s_read_reg(dev->i2s_base, IMR(i));
-			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x30);
-		}
-	} else {
+	else
 		i2s_write_reg(dev->i2s_base, IRER, 0);
 
-		for (i = 0; i < 4; i++) {
-			irq = i2s_read_reg(dev->i2s_base, IMR(i));
-			i2s_write_reg(dev->i2s_base, IMR(i), irq | 0x03);
-		}
-	}
+	i2s_disable_irqs(dev, substream->stream, 8);
 
 	if (!dev->active) {
 		i2s_write_reg(dev->i2s_base, CER, 0);

@@ -223,7 +241,7 @@ static int dw_i2s_startup(struct snd_pcm_substream *substream,
 
 static void dw_i2s_config(struct dw_i2s_dev *dev, int stream)
 {
-	u32 ch_reg, irq;
+	u32 ch_reg;
 	struct i2s_clk_config_data *config = &dev->config;
 
 

@@ -235,16 +253,12 @@ static void dw_i2s_config(struct dw_i2s_dev *dev, int stream)
 				      dev->xfer_resolution);
 			i2s_write_reg(dev->i2s_base, TFCR(ch_reg),
 				      dev->fifo_th - 1);
-			irq = i2s_read_reg(dev->i2s_base, IMR(ch_reg));
-			i2s_write_reg(dev->i2s_base, IMR(ch_reg), irq & ~0x30);
 			i2s_write_reg(dev->i2s_base, TER(ch_reg), 1);
 		} else {
 			i2s_write_reg(dev->i2s_base, RCR(ch_reg),
 				      dev->xfer_resolution);
 			i2s_write_reg(dev->i2s_base, RFCR(ch_reg),
 				      dev->fifo_th - 1);
-			irq = i2s_read_reg(dev->i2s_base, IMR(ch_reg));
-			i2s_write_reg(dev->i2s_base, IMR(ch_reg), irq & ~0x03);
 			i2s_write_reg(dev->i2s_base, RER(ch_reg), 1);
 		}
 

2.8.1

When using platform data the devm_clk_get() function is called causing a probe failure if the clock is not declared. As we can pass the clock handler by platform data call only devm_clk_get() when platform data is not used.

---

This patch was only introduced in v7.

 sound/soc/dwc/designware_i2s.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

index 4c4f0dc..a97be8e 100644
@@ -690,15 +690,16 @@ static int dw_i2s_probe(struct platform_device *pdev)
 				dev_err(&pdev->dev, "no clock configure method\n");
 				return -ENODEV;
 			}
-		}
-		dev->clk = devm_clk_get(&pdev->dev, clk_id);
+		} else {
+			dev->clk = devm_clk_get(&pdev->dev, clk_id);
 
-		if (IS_ERR(dev->clk))
-			return PTR_ERR(dev->clk);
+			if (IS_ERR(dev->clk))
+				return PTR_ERR(dev->clk);
 
-		ret = clk_prepare_enable(dev->clk);
-		if (ret < 0)
-			return ret;
+			ret = clk_prepare_enable(dev->clk);
+			if (ret < 0)
+				return ret;
+		}
 	}
 
 	dev_set_drvdata(&pdev->dev, dev);

1.9.1

No, this is broken - if the device needs a clock the device needs a clock and clock names should be static rather than passed in via platform data (indeed NULL is a perfectly valid clock name). The system integation should map in a clock as needed, if it's just a fixed crystal or something then just register a fixed clock and connect it up.

A PCM extension was added to I2S driver so that audio samples are transferred using PIO mode.

The PCM supports two channels @ 16 or 32 bits with rates 32k, 44.1k and 48k.

Although the mainline I2S driver uses ALSA DMA engine the I2S controller can be built without DMA support, therefore this is the reason why this extension was added.

The selection between the use of DMA engine or PIO mode is detected by declaring or not the interrupt parameters in the DT and using Kconfig.

---

Changes v6 -> v7:
* Discard the use of memcpy
* Report IRQ_HANDLED only when there is an IRQ
* Use interrupts to check if PIO mode is in use
* Unmask interrupts only when in PIO mode
* Remove empty functions

Changes v5 -> v6:
* Use SNDRV_DMA_TYPE_CONTINUOUS

Changes v4 -> v5:
* Resolve undefined references when compiling as module
* Use DMA properties in I2S to check which mode to use: PIO or DMA (as suggested by Lars-Peter Clausen)

Changes v3 -> v4:
* Reintroduced custom PCM driver
* Use DT boolean to switch between ALSA DMA engine PCM or custom PCM

Changes v2 -> v3:
* Removed pll_config functions (as suggested by Alexey Brodkin)
* Dropped custom platform driver, using now ALSA DMA engine
* Dropped IRQ handler for I2S

No changes v1 -> v2.

 sound/soc/dwc/Kconfig          |   9 ++
 sound/soc/dwc/Makefile         |   5 +-
 sound/soc/dwc/designware_i2s.c | 148 ++++++++++++---------------
 sound/soc/dwc/designware_pcm.c | 220 +++++++++++++++++++++++++++++++++++++++++
 sound/soc/dwc/local.h          | 122 +++++++++++++++++++++++
 5 files changed, 415 insertions(+), 89 deletions(-)
 create mode 100644 sound/soc/dwc/designware_pcm.c
 create mode 100644 sound/soc/dwc/local.h

index d50e085..c6fd95f 100644
@@ -7,4 +7,13 @@ config SND_DESIGNWARE_I2S
 	 Synopsys desigwnware I2S device. The device supports upto
 	 maximum of 8 channels each for play and record.
 
+config SND_DESIGNWARE_PCM
+	bool "PCM PIO extension for I2S driver"
+	depends on SND_DESIGNWARE_I2S
+	help
+	 Say Y or N if you want to add a custom ALSA extension that registers
+	 a PCM and uses PIO to transfer data.
+
+	 This functionality is specially suited for I2S devices that don't have
+	 DMA support.
 

index 319371f..11ea966 100644
@@ -1,3 +1,4 @@
 # SYNOPSYS Platform Support
-obj-$(CONFIG_SND_DESIGNWARE_I2S) += designware_i2s.o
-
+obj-$(CONFIG_SND_DESIGNWARE_I2S) += dwc_i2s.o
+dwc_i2s-y := designware_i2s.o
+dwc_i2s-$(CONFIG_SND_DESIGNWARE_PCM) += designware_pcm.o

1.9.1

Hi Mark,

Thanks for your comments.

I can change but my intention was to make this PCM a kind of extension to the driver instead of adding a new module to the system.

Ok.

Indeed I thought about this and the interrupts must also be enabled when in DMA mode. Although there is no interrupt handler in the original driver (without this patches) in some setups the interrupt line may be connected to the DMA controller. I will drop this change and always enable interrupts. Please note that I don't have a setup with DMA support so I can only test using the PIO mode.

How should I then determine which mode to use?
- Check if DMA parameters are declared in DT, or
- Check if snd_dmaengine_pcm_register() fails, or
- Assume PIO mode will be used when compiling with PIO PCM, or
- Something else ?

Best regards,
Jose Miguel Abreu

Please fix your mail client to word wrap within paragraphs at something substantially less than 80 columns. Doing this makes your messages much easier to read and reply to.

Presumably you can talk to your hardware colleagues and get them to make you a FPGA with a DMA IP available?

You could either unconditionally register the PIO driver and only actually start using it if the driver is instantiated or you could check to see if the registration function works (handling deferred probe - if the DMA driver just didn't load yet you should wait for it).

Hi Mark,

Its already in the todo list.

I think I will take the second option. Something like this:
"

    ret = snd_dmaengine_pcm_register(...)
    if (ret == -EPROBE_DEFER)
        return ret;
    else
        pio_register(...);

"?

Best regards,
Jose Miguel Abreu
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Sure. You should print a diagnostic if you fail to get the DMA, for any real system it's going to be a bug.

Hi Mark,

Ok, will do that. I noticed the last I2S patch that you merged ("ASoC: dwc: Add helper functions to disable/enable irqs") is not in for-next yet. Should I base my work on 'topic/dwc' branch?

Best regards,
Jose Miguel Abreu

We are in the merge window. No new non-bugfix patches will be merged until the merge window ends, most likely sometime this weekend.

A parameter description for the interruptions of the I2S controller was added. This interrupt parameter should only be set when I2S does not have DMA support.

---

Changes v6 -> v7:
* interrupts is now optional property

No changes v5 -> v6.

Changes v4 -> v5:
* interrupts is now required property
* Drop 'snps-use-dmaengine' property

This patch was only introduced in v4.

 Documentation/devicetree/bindings/sound/designware-i2s.txt | 4 ++++
 1 file changed, 4 insertions(+)

index 7bb5424..6a536d5 100644
@@ -12,6 +12,10 @@ Required properties:
    one for receive.
  - dma-names : "tx" for the transmit channel, "rx" for the receive channel.
 
+Optional properties:
+ - interrupts: The interrupt line number for the I2S controller. Add this
+   parameter if the I2S controller that you are using does not support DMA.
+
 For more details on the 'dma', 'dma-names', 'clock' and 'clock-names'
 properties please check:
 	* resource-names.txt

1.9.1

The patch

ASoC: dwc: Add irq parameter to DOCUMENTATION

has been applied to the asoc tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark

From: Jose Abreu <[email protected]>
Date: Thu, 9 Jun 2016 12:47:06 +0100
Subject: [PATCH] ASoC: dwc: Add irq parameter to DOCUMENTATION

A parameter description for the interruptions of the I2S controller was added.

---
 Documentation/devicetree/bindings/sound/designware-i2s.txt | 4 ++++
 1 file changed, 4 insertions(+)

index 7bb54247f8e8..6a536d570e29 100644
@@ -12,6 +12,10 @@ Required properties:
    one for receive.
  - dma-names : "tx" for the transmit channel, "rx" for the receive channel.
 
+Optional properties:
+ - interrupts: The interrupt line number for the I2S controller. Add this
+   parameter if the I2S controller that you are using does not support DMA.
+
 For more details on the 'dma', 'dma-names', 'clock' and 'clock-names'
 properties please check:
 	* resource-names.txt

2.8.1