[alsa-devel] [PATCH v3 2/2] ASoC: stm32: add SAI driver

Peter Meerwald-Stadler pmeerw at pmeerw.net
Mon Apr 10 17:43:24 CEST 2017


> This patch implements SAI ASoC driver for STM32.

some minor comments below 

> Signed-off-by: olivier moysan <olivier.moysan at st.com>
> ---
>  sound/soc/Kconfig             |   1 +
>  sound/soc/Makefile            |   1 +
>  sound/soc/stm/Kconfig         |   8 +
>  sound/soc/stm/Makefile        |   6 +
>  sound/soc/stm/stm32_sai.c     | 115 ++++++
>  sound/soc/stm/stm32_sai.h     | 200 ++++++++++
>  sound/soc/stm/stm32_sai_sub.c | 884 ++++++++++++++++++++++++++++++++++++++++++
>  7 files changed, 1215 insertions(+)
>  create mode 100644 sound/soc/stm/Kconfig
>  create mode 100644 sound/soc/stm/Makefile
>  create mode 100644 sound/soc/stm/stm32_sai.c
>  create mode 100644 sound/soc/stm/stm32_sai.h
>  create mode 100644 sound/soc/stm/stm32_sai_sub.c
> 
> diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
> index 182d92e..3836ebe 100644
> --- a/sound/soc/Kconfig
> +++ b/sound/soc/Kconfig
> @@ -63,6 +63,7 @@ source "sound/soc/sh/Kconfig"
>  source "sound/soc/sirf/Kconfig"
>  source "sound/soc/spear/Kconfig"
>  source "sound/soc/sti/Kconfig"
> +source "sound/soc/stm/Kconfig"
>  source "sound/soc/sunxi/Kconfig"
>  source "sound/soc/tegra/Kconfig"
>  source "sound/soc/txx9/Kconfig"
> diff --git a/sound/soc/Makefile b/sound/soc/Makefile
> index 9a30f21..5440cf7 100644
> --- a/sound/soc/Makefile
> +++ b/sound/soc/Makefile
> @@ -43,6 +43,7 @@ obj-$(CONFIG_SND_SOC)	+= sh/
>  obj-$(CONFIG_SND_SOC)	+= sirf/
>  obj-$(CONFIG_SND_SOC)	+= spear/
>  obj-$(CONFIG_SND_SOC)	+= sti/
> +obj-$(CONFIG_SND_SOC)	+= stm/
>  obj-$(CONFIG_SND_SOC)	+= sunxi/
>  obj-$(CONFIG_SND_SOC)	+= tegra/
>  obj-$(CONFIG_SND_SOC)	+= txx9/
> diff --git a/sound/soc/stm/Kconfig b/sound/soc/stm/Kconfig
> new file mode 100644
> index 0000000..972970f
> --- /dev/null
> +++ b/sound/soc/stm/Kconfig
> @@ -0,0 +1,8 @@
> +menuconfig SND_SOC_STM32
> +	tristate "STMicroelectronics STM32 SOC audio support"
> +	depends on ARCH_STM32 || COMPILE_TEST
> +	depends on SND_SOC
> +	select SND_SOC_GENERIC_DMAENGINE_PCM
> +	select REGMAP_MMIO
> +	help
> +	  Say Y if you want to enable ASoC-support for STM32

without '-' after ASoC probably

> diff --git a/sound/soc/stm/Makefile b/sound/soc/stm/Makefile
> new file mode 100644
> index 0000000..e466a47
> --- /dev/null
> +++ b/sound/soc/stm/Makefile
> @@ -0,0 +1,6 @@
> +# SAI
> +snd-soc-stm32-sai-sub-objs := stm32_sai_sub.o
> +obj-$(CONFIG_SND_SOC_STM32) += snd-soc-stm32-sai-sub.o
> +
> +snd-soc-stm32-sai-objs := stm32_sai.o
> +obj-$(CONFIG_SND_SOC_STM32) += snd-soc-stm32-sai.o
> diff --git a/sound/soc/stm/stm32_sai.c b/sound/soc/stm/stm32_sai.c
> new file mode 100644
> index 0000000..2a27a26
> --- /dev/null
> +++ b/sound/soc/stm/stm32_sai.c
> @@ -0,0 +1,115 @@
> +/*
> + * STM32 ALSA SoC Digital Audio Interface (SAI) driver.
> + *
> + * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
> + * Author(s): Olivier Moysan <olivier.moysan at st.com> for STMicroelectronics.
> + *
> + * License terms: GPL V2.0.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
> + * details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/reset.h>
> +
> +#include <sound/dmaengine_pcm.h>
> +#include <sound/core.h>
> +
> +#include "stm32_sai.h"
> +
> +static const struct of_device_id stm32_sai_ids[] = {
> +	{ .compatible = "st,stm32f4-sai", .data = (void *)SAI_STM32F4 },
> +	{}
> +};
> +
> +static int stm32_sai_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct stm32_sai_data *sai;
> +	struct reset_control *rst;
> +	struct resource *res;
> +	void __iomem *base;
> +	const struct of_device_id *of_id;
> +
> +	sai = devm_kzalloc(&pdev->dev, sizeof(*sai), GFP_KERNEL);
> +	if (!sai)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	of_id = of_match_device(stm32_sai_ids, &pdev->dev);
> +	if (of_id)
> +		sai->version = (enum stm32_sai_version)of_id->data;
> +	else
> +		return -EINVAL;
> +
> +	sai->clk_x8k = devm_clk_get(&pdev->dev, "x8k");
> +	if (IS_ERR(sai->clk_x8k)) {
> +		dev_err(&pdev->dev, "missing x8k parent clock\n");
> +		return PTR_ERR(sai->clk_x8k);
> +	}
> +
> +	sai->clk_x11k = devm_clk_get(&pdev->dev, "x11k");
> +	if (IS_ERR(sai->clk_x11k)) {
> +		dev_err(&pdev->dev, "missing x11k parent clock\n");
> +		return PTR_ERR(sai->clk_x11k);
> +	}
> +
> +	/* init irqs */
> +	sai->irq = platform_get_irq(pdev, 0);
> +	if (sai->irq < 0) {
> +		dev_err(&pdev->dev, "no irq for node %s\n", pdev->name);
> +		return sai->irq;
> +	}
> +
> +	/* reset */
> +	rst = reset_control_get(&pdev->dev, NULL);
> +	if (!IS_ERR(rst)) {
> +		reset_control_assert(rst);
> +		udelay(2);
> +		reset_control_deassert(rst);
> +	}
> +
> +	sai->pdev = pdev;
> +	platform_set_drvdata(pdev, sai);
> +
> +	return of_platform_populate(np, NULL, NULL, &pdev->dev);
> +}
> +
> +static int stm32_sai_remove(struct platform_device *pdev)
> +{
> +	of_platform_depopulate(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +MODULE_DEVICE_TABLE(of, stm32_sai_ids);
> +
> +static struct platform_driver stm32_sai_driver = {
> +	.driver = {
> +		.name = "st,stm32-sai",
> +		.of_match_table = stm32_sai_ids,
> +	},
> +	.probe = stm32_sai_probe,
> +	.remove = stm32_sai_remove,
> +};
> +
> +module_platform_driver(stm32_sai_driver);
> +
> +MODULE_DESCRIPTION("STM32 Soc SAI Interface");
> +MODULE_AUTHOR("Olivier Moysan, <olivier.moysan at st.com>");

, after your name?

> +MODULE_ALIAS("platform:st,stm32-sai");
> +MODULE_LICENSE("GPL v2");
> diff --git a/sound/soc/stm/stm32_sai.h b/sound/soc/stm/stm32_sai.h
> new file mode 100644
> index 0000000..a801fda
> --- /dev/null
> +++ b/sound/soc/stm/stm32_sai.h
> @@ -0,0 +1,200 @@
> +/*
> + * STM32 ALSA SoC Digital Audio Interface (SAI) driver.
> + *
> + * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
> + * Author(s): Olivier Moysan <olivier.moysan at st.com> for STMicroelectronics.
> + *
> + * License terms: GPL V2.0.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
> + * details.
> + */
> +
> +/******************** SAI Register Map **************************************/
> +
> +/* common register */
> +#define STM_SAI_GCR		0x00
> +
> +/* Sub-block A&B registers offsets, relative to A&B sub-block addresses */
> +#define STM_SAI_CR1_REGX	0x00	/* A offset: 0x04. B offset: 0x24 */
> +#define STM_SAI_CR2_REGX	0x04
> +#define STM_SAI_FRCR_REGX	0x08
> +#define STM_SAI_SLOTR_REGX	0x0C
> +#define STM_SAI_IMR_REGX	0x10
> +#define STM_SAI_SR_REGX		0x14
> +#define STM_SAI_CLRFR_REGX	0x18
> +#define STM_SAI_DR_REGX		0x1C
> +
> +/******************** Bit definition for SAI_GCR register *******************/
> +#define SAI_GCR_SYNCIN_SHIFT	0
> +#define SAI_GCR_SYNCIN_MASK	GENMASK(1, SAI_GCR_SYNCIN_SHIFT)
> +#define SAI_GCR_SYNCIN_SET(x)	((x) << SAI_GCR_SYNCIN_SHIFT)
> +
> +#define SAI_GCR_SYNCOUT_SHIFT	4
> +#define SAI_GCR_SYNCOUT_MASK	GENMASK(5, SAI_GCR_SYNCOUT_SHIFT)
> +#define SAI_GCR_SYNCOUT_SET(x)	((x) << SAI_GCR_SYNCOUT_SHIFT)
> +
> +/******************* Bit definition for SAI_XCR1 register *******************/
> +#define SAI_XCR1_RX_TX_SHIFT	0
> +#define SAI_XCR1_RX_TX		BIT(SAI_XCR1_RX_TX_SHIFT)
> +#define SAI_XCR1_SLAVE_SHIFT	1
> +#define SAI_XCR1_SLAVE		BIT(SAI_XCR1_SLAVE_SHIFT)
> +
> +#define SAI_XCR1_PRTCFG_SHIFT	2
> +#define SAI_XCR1_PRTCFG_MASK	GENMASK(3, SAI_XCR1_PRTCFG_SHIFT)
> +#define SAI_XCR1_PRTCFG_SET(x)	((x) << SAI_XCR1_PRTCFG_SHIFT)
> +
> +#define SAI_XCR1_DS_SHIFT	5
> +#define SAI_XCR1_DS_MASK	GENMASK(7, SAI_XCR1_DS_SHIFT)
> +#define SAI_XCR1_DS_SET(x)	((x) << SAI_XCR1_DS_SHIFT)
> +
> +#define SAI_XCR1_LSBFIRST_SHIFT	8
> +#define SAI_XCR1_LSBFIRST	BIT(SAI_XCR1_LSBFIRST_SHIFT)
> +#define SAI_XCR1_CKSTR_SHIFT	9
> +#define SAI_XCR1_CKSTR		BIT(SAI_XCR1_CKSTR_SHIFT)
> +
> +#define SAI_XCR1_SYNCEN_SHIFT	10
> +#define SAI_XCR1_SYNCEN_MASK	GENMASK(11, SAI_XCR1_SYNCEN_SHIFT)
> +#define SAI_XCR1_SYNCEN_SET(x)	((x) << SAI_XCR1_SYNCEN_SHIFT)
> +
> +#define SAI_XCR1_MONO_SHIFT	12
> +#define SAI_XCR1_MONO		BIT(SAI_XCR1_MONO_SHIFT)
> +#define SAI_XCR1_OUTDRIV_SHIFT	13
> +#define SAI_XCR1_OUTDRIV	BIT(SAI_XCR1_OUTDRIV_SHIFT)
> +#define SAI_XCR1_SAIEN_SHIFT	16
> +#define SAI_XCR1_SAIEN		BIT(SAI_XCR1_SAIEN_SHIFT)
> +#define SAI_XCR1_DMAEN_SHIFT	17
> +#define SAI_XCR1_DMAEN		BIT(SAI_XCR1_DMAEN_SHIFT)
> +#define SAI_XCR1_NODIV_SHIFT	19
> +#define SAI_XCR1_NODIV		BIT(SAI_XCR1_NODIV_SHIFT)
> +
> +#define SAI_XCR1_MCKDIV_SHIFT	20
> +#define SAI_XCR1_MCKDIV_WIDTH	4
> +#define SAI_XCR1_MCKDIV_MASK	GENMASK(24, SAI_XCR1_MCKDIV_SHIFT)
> +#define SAI_XCR1_MCKDIV_SET(x)	((x) << SAI_XCR1_MCKDIV_SHIFT)
> +#define SAI_XCR1_MCKDIV_MAX	((1 << SAI_XCR1_MCKDIV_WIDTH) - 1)
> +
> +#define SAI_XCR1_OSR_SHIFT	26
> +#define SAI_XCR1_OSR		BIT(SAI_XCR1_OSR_SHIFT)
> +
> +/******************* Bit definition for SAI_XCR2 register *******************/
> +#define SAI_XCR2_FTH_SHIFT	0
> +#define SAI_XCR2_FTH_MASK	GENMASK(2, SAI_XCR2_FTH_SHIFT)
> +#define SAI_XCR2_FTH_SET(x)	((x) << SAI_XCR2_FTH_SHIFT)
> +
> +#define SAI_XCR2_FFLUSH_SHIFT	3
> +#define SAI_XCR2_FFLUSH		BIT(SAI_XCR2_FFLUSH_SHIFT)
> +#define SAI_XCR2_TRIS_SHIFT	4
> +#define SAI_XCR2_TRIS		BIT(SAI_XCR2_TRIS_SHIFT)
> +#define SAI_XCR2_MUTE_SHIFT	5
> +#define SAI_XCR2_MUTE		BIT(SAI_XCR2_MUTE_SHIFT)
> +#define SAI_XCR2_MUTEVAL_SHIFT	6
> +#define SAI_XCR2_MUTEVAL	BIT(SAI_XCR2_MUTEVAL_SHIFT)
> +
> +#define SAI_XCR2_MUTECNT_SHIFT	7
> +#define SAI_XCR2_MUTECNT_MASK	GENMASK(12, SAI_XCR2_MUTECNT_SHIFT)
> +#define SAI_XCR2_MUTECNT_SET(x)	((x) << SAI_XCR2_MUTECNT_SHIFT)
> +
> +#define SAI_XCR2_CPL_SHIFT	13
> +#define SAI_XCR2_CPL		BIT(SAI_XCR2_CPL_SHIFT)
> +
> +#define SAI_XCR2_COMP_SHIFT	14
> +#define SAI_XCR2_COMP_MASK	GENMASK(15, SAI_XCR2_COMP_SHIFT)
> +#define SAI_XCR2_COMP_SET(x)	((x) << SAI_XCR2_COMP_SHIFT)
> +
> +/****************** Bit definition for SAI_XFRCR register *******************/
> +#define SAI_XFRCR_FRL_SHIFT	0
> +#define SAI_XFRCR_FRL_MASK	GENMASK(7, SAI_XFRCR_FRL_SHIFT)
> +#define SAI_XFRCR_FRL_SET(x)	((x) << SAI_XFRCR_FRL_SHIFT)
> +
> +#define SAI_XFRCR_FSALL_SHIFT	8
> +#define SAI_XFRCR_FSALL_MASK	GENMASK(14, SAI_XFRCR_FSALL_SHIFT)
> +#define SAI_XFRCR_FSALL_SET(x)	((x) << SAI_XFRCR_FSALL_SHIFT)
> +
> +#define SAI_XFRCR_FSDEF_SHIFT	16
> +#define SAI_XFRCR_FSDEF		BIT(SAI_XFRCR_FSDEF_SHIFT)
> +#define SAI_XFRCR_FSPOL_SHIFT	17
> +#define SAI_XFRCR_FSPOL		BIT(SAI_XFRCR_FSPOL_SHIFT)
> +#define SAI_XFRCR_FSOFF_SHIFT	18
> +#define SAI_XFRCR_FSOFF		BIT(SAI_XFRCR_FSOFF_SHIFT)
> +
> +/****************** Bit definition for SAI_XSLOTR register ******************/

no newline (as above)?

> +
> +#define SAI_XSLOTR_FBOFF_SHIFT	0
> +#define SAI_XSLOTR_FBOFF_MASK	GENMASK(4, SAI_XSLOTR_FBOFF_SHIFT)
> +#define SAI_XSLOTR_FBOFF_SET(x)	((x) << SAI_XSLOTR_FBOFF_SHIFT)
> +
> +#define SAI_XSLOTR_SLOTSZ_SHIFT	6
> +#define SAI_XSLOTR_SLOTSZ_MASK	GENMASK(7, SAI_XSLOTR_SLOTSZ_SHIFT)
> +#define SAI_XSLOTR_SLOTSZ_SET(x)	((x) << SAI_XSLOTR_SLOTSZ_SHIFT)
> +
> +#define SAI_XSLOTR_NBSLOT_SHIFT 8
> +#define SAI_XSLOTR_NBSLOT_MASK	GENMASK(11, SAI_XSLOTR_NBSLOT_SHIFT)
> +#define SAI_XSLOTR_NBSLOT_SET(x) ((x) << SAI_XSLOTR_NBSLOT_SHIFT)
> +
> +#define SAI_XSLOTR_SLOTEN_SHIFT	16
> +#define SAI_XSLOTR_SLOTEN_WIDTH	16
> +#define SAI_XSLOTR_SLOTEN_MASK	GENMASK(31, SAI_XSLOTR_SLOTEN_SHIFT)
> +#define SAI_XSLOTR_SLOTEN_SET(x) ((x) << SAI_XSLOTR_SLOTEN_SHIFT)
> +
> +/******************* Bit definition for SAI_XIMR register *******************/
> +#define SAI_XIMR_OVRUDRIE	BIT(0)
> +#define SAI_XIMR_MUTEDETIE	BIT(1)
> +#define SAI_XIMR_WCKCFGIE	BIT(2)
> +#define SAI_XIMR_FREQIE		BIT(3)
> +#define SAI_XIMR_CNRDYIE	BIT(4)
> +#define SAI_XIMR_AFSDETIE	BIT(5)
> +#define SAI_XIMR_LFSDETIE	BIT(6)
> +
> +#define SAI_XIMR_SHIFT	0
> +#define SAI_XIMR_MASK		GENMASK(6, SAI_XIMR_SHIFT)
> +
> +/******************** Bit definition for SAI_XSR register *******************/
> +#define SAI_XSR_OVRUDR		BIT(0)
> +#define SAI_XSR_MUTEDET		BIT(1)
> +#define SAI_XSR_WCKCFG		BIT(2)
> +#define SAI_XSR_FREQ		BIT(3)
> +#define SAI_XSR_CNRDY		BIT(4)
> +#define SAI_XSR_AFSDET		BIT(5)
> +#define SAI_XSR_LFSDET		BIT(6)
> +
> +#define SAI_XSR_SHIFT	0
> +#define SAI_XSR_MASK		GENMASK(6, SAI_XSR_SHIFT)
> +
> +/****************** Bit definition for SAI_XCLRFR register ******************/
> +#define SAI_XCLRFR_COVRUDR	BIT(0)
> +#define SAI_XCLRFR_CMUTEDET	BIT(1)
> +#define SAI_XCLRFR_CWCKCFG	BIT(2)
> +#define SAI_XCLRFR_CFREQ	BIT(3)
> +#define SAI_XCLRFR_CCNRDY	BIT(4)
> +#define SAI_XCLRFR_CAFSDET	BIT(5)
> +#define SAI_XCLRFR_CLFSDET	BIT(6)
> +
> +#define SAI_XCLRFR_SHIFT	0
> +#define SAI_XCLRFR_MASK		GENMASK(6, SAI_XCLRFR_SHIFT)
> +
> +enum stm32_sai_version {
> +	SAI_STM32F4
> +};
> +
> +/**
> + * struct stm32_sai_data - private data of SAI instance driver
> + * @pdev: device data pointer
> + * @clk_x8k: SAI parent clock for sampling frequencies multiple of 8kHz
> + * @clk_x11k: SAI parent clock for sampling frequencies multiple of 11kHz
> + * @version: SOC version
> + * @irq: SAI interrupt line
> + */
> +struct stm32_sai_data {
> +	struct platform_device *pdev;
> +	struct clk *clk_x8k;
> +	struct clk *clk_x11k;
> +	int version;
> +	int irq;
> +};
> diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
> new file mode 100644
> index 0000000..ae4706c
> --- /dev/null
> +++ b/sound/soc/stm/stm32_sai_sub.c
> @@ -0,0 +1,884 @@
> +/*
> + * STM32 ALSA SoC Digital Audio Interface (SAI) driver.
> + *
> + * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
> + * Author(s): Olivier Moysan <olivier.moysan at st.com> for STMicroelectronics.
> + *
> + * License terms: GPL V2.0.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
> + * details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +#include <linux/regmap.h>
> +
> +#include <sound/core.h>
> +#include <sound/dmaengine_pcm.h>
> +#include <sound/pcm_params.h>
> +
> +#include "stm32_sai.h"
> +
> +#define SAI_FREE_PROTOCOL	0x0
> +
> +#define SAI_SLOT_SIZE_AUTO	0x0
> +#define SAI_SLOT_SIZE_16	0x1
> +#define SAI_SLOT_SIZE_32	0x2
> +
> +#define SAI_DATASIZE_8		0x2
> +#define SAI_DATASIZE_10		0x3
> +#define SAI_DATASIZE_16		0x4
> +#define SAI_DATASIZE_20		0x5
> +#define SAI_DATASIZE_24		0x6
> +#define SAI_DATASIZE_32		0x7
> +
> +#define STM_SAI_FIFO_SIZE	8
> +#define STM_SAI_DAI_NAME_SIZE	15
> +
> +#define STM_SAI_IS_PLAYBACK(ip)	((ip)->dir == SNDRV_PCM_STREAM_PLAYBACK)
> +#define STM_SAI_IS_CAPTURE(ip)	((ip)->dir == SNDRV_PCM_STREAM_CAPTURE)
> +
> +#define STM_SAI_A_ID		0x0
> +#define STM_SAI_B_ID		0x1
> +
> +#define STM_SAI_BLOCK_NAME(x)	(((x)->id == STM_SAI_A_ID) ? "A" : "B")
> +
> +/**
> + * struct stm32_sai_sub_data - private data of SAI sub block (block A or B)
> + * @pdev: device data pointer
> + * @regmap: SAI register map pointer
> + * @dma_params: dma configuration data for rx or tx channel
> + * @cpu_dai_drv: DAI driver data pointer
> + * @cpu_dai: DAI runtime data pointer
> + * @substream: PCM substream data pointer
> + * @pdata: SAI block parent data pointer
> + * @sai_ck: kernel clock feeding the SAI clock generator
> + * @phys_addr: SAI registers physical base address
> + * @mclk_rate: SAI block master clock frequency (Hz). set at init
> + * @id: SAI sub block id corresponding to sub-block A or B
> + * @dir: SAI block direction (playback or capture). set at init
> + * @master: SAI block mode flag. (true=master, false=slave) set at init
> + * @fmt: SAI block format. relevant only for custom protocols. set at init
> + * @sync: SAI block synchronization mode. (none, internal or external)
> + * @fs_length: frame synchronization length. depends on protocol settings
> + * @slots: rx or tx slot number
> + * @slot_width: rx or tx slot width in bits
> + * @slot_mask: rx or tx active slots mask. set at init or at runtime
> + * @data_size: PCM data width. corresponds to PCM substream width.
> + */
> +struct stm32_sai_sub_data {
> +	struct platform_device *pdev;
> +	struct regmap *regmap;
> +	struct snd_dmaengine_dai_dma_data dma_params;
> +	struct snd_soc_dai_driver *cpu_dai_drv;
> +	struct snd_soc_dai *cpu_dai;
> +	struct snd_pcm_substream *substream;
> +	struct stm32_sai_data *pdata;
> +	struct clk *sai_ck;
> +	dma_addr_t phys_addr;
> +	unsigned int mclk_rate;
> +	unsigned int id;
> +	int dir;
> +	bool master;
> +	int fmt;
> +	int sync;
> +	int fs_length;
> +	int slots;
> +	int slot_width;
> +	int slot_mask;
> +	int data_size;
> +};
> +
> +enum stm32_sai_fifo_th {
> +	STM_SAI_FIFO_TH_EMPTY,
> +	STM_SAI_FIFO_TH_QUARTER,
> +	STM_SAI_FIFO_TH_HALF,
> +	STM_SAI_FIFO_TH_3_QUARTER,
> +	STM_SAI_FIFO_TH_FULL,
> +};
> +
> +static bool stm32_sai_sub_readable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case STM_SAI_CR1_REGX:
> +	case STM_SAI_CR2_REGX:
> +	case STM_SAI_FRCR_REGX:
> +	case STM_SAI_SLOTR_REGX:
> +	case STM_SAI_IMR_REGX:
> +	case STM_SAI_SR_REGX:
> +	case STM_SAI_CLRFR_REGX:
> +	case STM_SAI_DR_REGX:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool stm32_sai_sub_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case STM_SAI_DR_REGX:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool stm32_sai_sub_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case STM_SAI_CR1_REGX:
> +	case STM_SAI_CR2_REGX:
> +	case STM_SAI_FRCR_REGX:
> +	case STM_SAI_SLOTR_REGX:
> +	case STM_SAI_IMR_REGX:
> +	case STM_SAI_SR_REGX:
> +	case STM_SAI_CLRFR_REGX:
> +	case STM_SAI_DR_REGX:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config stm32_sai_sub_regmap_config = {
> +	.reg_bits = 32,
> +	.reg_stride = 4,
> +	.val_bits = 32,
> +	.max_register = STM_SAI_DR_REGX,
> +	.readable_reg = stm32_sai_sub_readable_reg,
> +	.volatile_reg = stm32_sai_sub_volatile_reg,
> +	.writeable_reg = stm32_sai_sub_writeable_reg,
> +	.fast_io = true,
> +};
> +
> +static irqreturn_t stm32_sai_isr(int irq, void *devid)
> +{
> +	struct stm32_sai_sub_data *sai = (struct stm32_sai_sub_data *)devid;
> +	struct snd_pcm_substream *substream = sai->substream;
> +	struct platform_device *pdev = sai->pdev;
> +	unsigned int sr, imr, flags;
> +	snd_pcm_state_t status = SNDRV_PCM_STATE_RUNNING;
> +
> +	regmap_read(sai->regmap, STM_SAI_IMR_REGX, &imr);
> +	regmap_read(sai->regmap, STM_SAI_SR_REGX, &sr);
> +
> +	flags = sr & imr;
> +	if (!flags)
> +		return IRQ_NONE;
> +
> +	regmap_update_bits(sai->regmap, STM_SAI_CLRFR_REGX, SAI_XCLRFR_MASK,
> +			   SAI_XCLRFR_MASK);
> +
> +	if (flags & SAI_XIMR_OVRUDRIE) {
> +		dev_err(&pdev->dev, "IT %s\n",

wondering what IT is

> +			STM_SAI_IS_PLAYBACK(sai) ? "underrun" : "overrun");
> +		status = SNDRV_PCM_STATE_XRUN;
> +	}
> +
> +	if (flags & SAI_XIMR_MUTEDETIE)
> +		dev_dbg(&pdev->dev, "IT mute detected\n");
> +
> +	if (flags & SAI_XIMR_WCKCFGIE) {
> +		dev_err(&pdev->dev, "IT wrong clock configuration\n");
> +		status = SNDRV_PCM_STATE_DISCONNECTED;
> +	}
> +
> +	if (flags & SAI_XIMR_CNRDYIE)
> +		dev_warn(&pdev->dev, "IT Codec not ready\n");
> +
> +	if (flags & SAI_XIMR_AFSDETIE) {
> +		dev_warn(&pdev->dev, "IT Anticipated frame synchro\n");
> +		status = SNDRV_PCM_STATE_XRUN;
> +	}
> +
> +	if (flags & SAI_XIMR_LFSDETIE) {
> +		dev_warn(&pdev->dev, "IT Late frame synchro\n");
> +		status = SNDRV_PCM_STATE_XRUN;
> +	}
> +
> +	if (status != SNDRV_PCM_STATE_RUNNING) {
> +		snd_pcm_stream_lock(substream);
> +		snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
> +		snd_pcm_stream_unlock(substream);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int stm32_sai_set_sysclk(struct snd_soc_dai *cpu_dai,
> +				int clk_id, unsigned int freq, int dir)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +
> +	if ((dir == SND_SOC_CLOCK_OUT) && sai->master) {
> +		sai->mclk_rate = freq;
> +		dev_dbg(cpu_dai->dev, "SAI MCLK frequency is %uHz\n", freq);
> +	}
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai, u32 tx_mask,
> +				      u32 rx_mask, int slots, int slot_width)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int slotr, slotr_mask, slot_size;
> +
> +	dev_dbg(cpu_dai->dev, "masks tx/rx:%#x/%#x, slots:%d, width:%d\n",
> +		tx_mask, rx_mask, slots, slot_width);
> +
> +	switch (slot_width) {
> +	case 16:
> +		slot_size = SAI_SLOT_SIZE_16;
> +		break;
> +	case 32:
> +		slot_size = SAI_SLOT_SIZE_32;
> +		break;
> +	default:
> +		slot_size = SAI_SLOT_SIZE_AUTO;
> +		break;
> +	}
> +
> +	slotr = SAI_XSLOTR_SLOTSZ_SET(slot_size) |
> +		SAI_XSLOTR_NBSLOT_SET(slots - 1);
> +	slotr_mask = SAI_XSLOTR_SLOTSZ_MASK | SAI_XSLOTR_NBSLOT_MASK;
> +
> +	/* tx/rx mask set in machine init, if slot number defined in DT */
> +	if (STM_SAI_IS_PLAYBACK(sai)) {
> +		sai->slot_mask = tx_mask;
> +		slotr |= SAI_XSLOTR_SLOTEN_SET(tx_mask);
> +	}
> +
> +	if (STM_SAI_IS_CAPTURE(sai)) {
> +		sai->slot_mask = rx_mask;
> +		slotr |= SAI_XSLOTR_SLOTEN_SET(rx_mask);
> +	}
> +
> +	slotr_mask |= SAI_XSLOTR_SLOTEN_MASK;
> +
> +	regmap_update_bits(sai->regmap, STM_SAI_SLOTR_REGX, slotr_mask, slotr);
> +
> +	sai->slot_width = slot_width;
> +	sai->slots = slots;
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int cr1 = 0, frcr = 0;
> +	int cr1_mask = 0, frcr_mask = 0;
> +	int ret;
> +
> +	dev_dbg(cpu_dai->dev, "fmt %x\n", fmt);
> +
> +	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
> +	/* SCK active high for all protocols */
> +	case SND_SOC_DAIFMT_I2S:
> +		cr1 |= SAI_XCR1_CKSTR;
> +		frcr |= SAI_XFRCR_FSOFF | SAI_XFRCR_FSDEF;
> +		break;
> +	/* Left justified */
> +	case SND_SOC_DAIFMT_MSB:
> +		frcr |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSDEF;
> +		break;
> +	/* Right justified */
> +	case SND_SOC_DAIFMT_LSB:
> +		frcr |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSDEF;
> +		break;
> +	case SND_SOC_DAIFMT_DSP_A:
> +		frcr |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSOFF;
> +		break;
> +	case SND_SOC_DAIFMT_DSP_B:
> +		frcr |= SAI_XFRCR_FSPOL;
> +		break;
> +	default:
> +		dev_err(cpu_dai->dev, "Unsupported protocol %#x\n",

nitpicking: messages are somethings starting uppercase, sometimes 
lowercase

> +			fmt & SND_SOC_DAIFMT_FORMAT_MASK);
> +		return -EINVAL;
> +	}
> +
> +	cr1_mask |= SAI_XCR1_PRTCFG_MASK | SAI_XCR1_CKSTR;
> +	frcr_mask |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSOFF |
> +		     SAI_XFRCR_FSDEF;
> +
> +	/* DAI clock strobing. Invert setting previously set */
> +	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
> +	case SND_SOC_DAIFMT_NB_NF:
> +		break;
> +	case SND_SOC_DAIFMT_IB_NF:
> +		cr1 ^= SAI_XCR1_CKSTR;
> +		break;
> +	case SND_SOC_DAIFMT_NB_IF:
> +		frcr ^= SAI_XFRCR_FSPOL;
> +		break;
> +	case SND_SOC_DAIFMT_IB_IF:
> +		/* Invert fs & sck */
> +		cr1 ^= SAI_XCR1_CKSTR;
> +		frcr ^= SAI_XFRCR_FSPOL;
> +		break;
> +	default:
> +		dev_err(cpu_dai->dev, "Unsupported strobing %#x\n",
> +			fmt & SND_SOC_DAIFMT_INV_MASK);
> +		return -EINVAL;
> +	}
> +	cr1_mask |= SAI_XCR1_CKSTR;
> +	frcr_mask |= SAI_XFRCR_FSPOL;
> +
> +	regmap_update_bits(sai->regmap, STM_SAI_FRCR_REGX, frcr_mask, frcr);
> +
> +	/* DAI clock master masks */
> +	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
> +	case SND_SOC_DAIFMT_CBM_CFM:
> +		/* codec is master */
> +		cr1 |= SAI_XCR1_SLAVE;
> +		sai->master = false;
> +		break;
> +	case SND_SOC_DAIFMT_CBS_CFS:
> +		sai->master = true;
> +		break;
> +	default:
> +		dev_err(cpu_dai->dev, "Unsupported mode %#x\n",
> +			fmt & SND_SOC_DAIFMT_MASTER_MASK);
> +		return -EINVAL;
> +	}
> +	cr1_mask |= SAI_XCR1_SLAVE;
> +
> +	ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, cr1_mask, cr1);
> +	if (ret < 0) {
> +		dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
> +		return ret;
> +	}
> +
> +	sai->fmt = fmt;
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_startup(struct snd_pcm_substream *substream,
> +			     struct snd_soc_dai *cpu_dai)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int imr, cr2, ret;
> +
> +	sai->substream = substream;
> +
> +	ret = clk_prepare_enable(sai->sai_ck);
> +	if (ret < 0) {
> +		dev_err(cpu_dai->dev, "failed to enable clock: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* Enable ITs */
> +	regmap_update_bits(sai->regmap, STM_SAI_SR_REGX,
> +			   SAI_XSR_MASK, (unsigned int)~SAI_XSR_MASK);
> +
> +	regmap_update_bits(sai->regmap, STM_SAI_CLRFR_REGX,
> +			   SAI_XCLRFR_MASK, SAI_XCLRFR_MASK);
> +
> +	imr = SAI_XIMR_OVRUDRIE;
> +	if (STM_SAI_IS_CAPTURE(sai)) {
> +		regmap_read(sai->regmap, STM_SAI_CR2_REGX, &cr2);
> +		if (cr2 & SAI_XCR2_MUTECNT_MASK)
> +			imr |= SAI_XIMR_MUTEDETIE;
> +	}
> +
> +	if (sai->master)
> +		imr |= SAI_XIMR_WCKCFGIE;
> +	else
> +		imr |= SAI_XIMR_AFSDETIE | SAI_XIMR_LFSDETIE;
> +
> +	regmap_update_bits(sai->regmap, STM_SAI_IMR_REGX,
> +			   SAI_XIMR_MASK, imr);
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_set_config(struct snd_soc_dai *cpu_dai,
> +				struct snd_pcm_substream *substream,
> +				struct snd_pcm_hw_params *params)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int cr1, cr1_mask, ret;
> +	int fth = STM_SAI_FIFO_TH_HALF;
> +
> +	/* FIFO config */
> +	regmap_update_bits(sai->regmap, STM_SAI_CR2_REGX,
> +			   SAI_XCR2_FFLUSH | SAI_XCR2_FTH_MASK,
> +			   SAI_XCR2_FFLUSH | SAI_XCR2_FTH_SET(fth));
> +
> +	/* Mode, data format and channel config */
> +	cr1 = SAI_XCR1_PRTCFG_SET(SAI_FREE_PROTOCOL);
> +	switch (params_format(params)) {
> +	case SNDRV_PCM_FORMAT_S8:
> +		cr1 |= SAI_XCR1_DS_SET(SAI_DATASIZE_8);
> +		break;
> +	case SNDRV_PCM_FORMAT_S16_LE:
> +		cr1 |= SAI_XCR1_DS_SET(SAI_DATASIZE_16);
> +		break;
> +	case SNDRV_PCM_FORMAT_S32_LE:
> +		cr1 |= SAI_XCR1_DS_SET(SAI_DATASIZE_32);
> +		break;
> +	default:
> +		dev_err(cpu_dai->dev, "Data format not supported");
> +		return -EINVAL;
> +	}
> +	cr1_mask = SAI_XCR1_DS_MASK | SAI_XCR1_PRTCFG_MASK;
> +
> +	cr1_mask |= SAI_XCR1_RX_TX;
> +	if (STM_SAI_IS_CAPTURE(sai))
> +		cr1 |= SAI_XCR1_RX_TX;
> +
> +	cr1_mask |= SAI_XCR1_MONO;
> +	if ((sai->slots == 2) && (params_channels(params) == 1))
> +		cr1 |= SAI_XCR1_MONO;
> +
> +	ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, cr1_mask, cr1);
> +	if (ret < 0) {
> +		dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
> +		return ret;
> +	}
> +
> +	/* DMA config */
> +	sai->dma_params.maxburst = STM_SAI_FIFO_SIZE * fth / sizeof(u32);
> +	snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)&sai->dma_params);
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_set_slots(struct snd_soc_dai *cpu_dai)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int slotr, slot_sz;
> +
> +	regmap_read(sai->regmap, STM_SAI_SLOTR_REGX, &slotr);
> +
> +	/*
> +	 * If SLOTSZ is set to auto in SLOTR, align slot width on data size
> +	 * By default slot width = data size, if not forced from DT
> +	 */
> +	slot_sz = slotr & SAI_XSLOTR_SLOTSZ_MASK;
> +	if (slot_sz == SAI_XSLOTR_SLOTSZ_SET(SAI_SLOT_SIZE_AUTO))
> +		sai->slot_width = sai->data_size;
> +
> +	if (sai->slot_width < sai->data_size) {
> +		dev_err(cpu_dai->dev,
> +			"Data size %d larger than slot width\n",
> +			sai->data_size);
> +		return -EINVAL;
> +	}
> +
> +	/* Slot number is set to 2, if not specified in DT */
> +	if (!sai->slots)
> +		sai->slots = 2;
> +
> +	/* The number of slots in the audio frame is equal to NBSLOT[3:0] + 1*/
> +	regmap_update_bits(sai->regmap, STM_SAI_SLOTR_REGX,
> +			   SAI_XSLOTR_NBSLOT_MASK,
> +			   SAI_XSLOTR_NBSLOT_SET((sai->slots - 1)));
> +
> +	/* Set default slots mask if not already set from DT */
> +	if (!(slotr & SAI_XSLOTR_SLOTEN_MASK)) {
> +		sai->slot_mask = (1 << sai->slots) - 1;
> +		regmap_update_bits(sai->regmap,
> +				   STM_SAI_SLOTR_REGX, SAI_XSLOTR_SLOTEN_MASK,
> +				   SAI_XSLOTR_SLOTEN_SET(sai->slot_mask));
> +	}
> +
> +	dev_dbg(cpu_dai->dev, "slots %d, slot width %d\n",
> +		sai->slots, sai->slot_width);
> +
> +	return 0;
> +}
> +
> +static void stm32_sai_set_frame(struct snd_soc_dai *cpu_dai)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int fs_active, offset, format;
> +	int frcr, frcr_mask;
> +
> +	format = sai->fmt & SND_SOC_DAIFMT_FORMAT_MASK;
> +	sai->fs_length = sai->slot_width * sai->slots;
> +
> +	fs_active = sai->fs_length / 2;
> +	if ((format == SND_SOC_DAIFMT_DSP_A) ||
> +	    (format == SND_SOC_DAIFMT_DSP_B))
> +		fs_active = 1;
> +
> +	frcr = SAI_XFRCR_FRL_SET((sai->fs_length - 1));
> +	frcr |= SAI_XFRCR_FSALL_SET((fs_active - 1));
> +	frcr_mask = SAI_XFRCR_FRL_MASK | SAI_XFRCR_FSALL_MASK;
> +
> +	dev_dbg(cpu_dai->dev, "frame length %d, frame active %d\n",
> +		sai->fs_length, fs_active);
> +
> +	regmap_update_bits(sai->regmap, STM_SAI_FRCR_REGX, frcr_mask, frcr);
> +
> +	if ((sai->fmt & SND_SOC_DAIFMT_FORMAT_MASK) == SND_SOC_DAIFMT_LSB) {
> +		offset = sai->slot_width - sai->data_size;
> +
> +		regmap_update_bits(sai->regmap, STM_SAI_SLOTR_REGX,
> +				   SAI_XSLOTR_FBOFF_MASK,
> +				   SAI_XSLOTR_FBOFF_SET(offset));
> +	}
> +}
> +
> +static int stm32_sai_configure_clock(struct snd_soc_dai *cpu_dai,
> +				     struct snd_pcm_hw_params *params)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int cr1, mask, div = 0;
> +	int sai_clk_rate, ret;
> +
> +	if (!sai->mclk_rate) {
> +		dev_err(cpu_dai->dev, "Mclk rate is null\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!(params_rate(params) % 11025))
> +		clk_set_parent(sai->sai_ck, sai->pdata->clk_x11k);
> +	else
> +		clk_set_parent(sai->sai_ck, sai->pdata->clk_x8k);
> +	sai_clk_rate = clk_get_rate(sai->sai_ck);
> +
> +	/*
> +	 * mclk_rate = 256 * fs
> +	 * MCKDIV = 0 if sai_ck < 3/2 * mclk_rate
> +	 * MCKDIV = sai_ck / (2 * mclk_rate) otherwise
> +	 */
> +	if (2 * sai_clk_rate >= 3 * sai->mclk_rate)
> +		div = DIV_ROUND_CLOSEST(sai_clk_rate, 2 * sai->mclk_rate);
> +
> +	if (div > SAI_XCR1_MCKDIV_MAX) {
> +		dev_err(cpu_dai->dev, "Divider %d out of range\n", div);
> +		return -EINVAL;
> +	}
> +	dev_dbg(cpu_dai->dev, "SAI clock %d, divider %d\n", sai_clk_rate, div);
> +
> +	mask = SAI_XCR1_MCKDIV_MASK;
> +	cr1 = SAI_XCR1_MCKDIV_SET(div);
> +	ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, mask, cr1);
> +	if (ret < 0) {
> +		dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_hw_params(struct snd_pcm_substream *substream,
> +			       struct snd_pcm_hw_params *params,
> +			       struct snd_soc_dai *cpu_dai)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int ret;
> +
> +	sai->data_size = params_width(params);
> +
> +	ret = stm32_sai_set_slots(cpu_dai);
> +	if (ret < 0)
> +		return ret;
> +	stm32_sai_set_frame(cpu_dai);
> +
> +	ret = stm32_sai_set_config(cpu_dai, substream, params);
> +	if (ret)
> +		return ret;
> +
> +	if (sai->master)
> +		ret = stm32_sai_configure_clock(cpu_dai, params);
> +
> +	return ret;
> +}
> +
> +static int stm32_sai_trigger(struct snd_pcm_substream *substream, int cmd,
> +			     struct snd_soc_dai *cpu_dai)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +	int ret;
> +
> +	switch (cmd) {
> +	case SNDRV_PCM_TRIGGER_START:
> +	case SNDRV_PCM_TRIGGER_RESUME:
> +	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +		dev_dbg(cpu_dai->dev, "Enable DMA and SAI\n");
> +
> +		regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
> +				   SAI_XCR1_DMAEN, SAI_XCR1_DMAEN);
> +
> +		/* Enable SAI */
> +		ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
> +					 SAI_XCR1_SAIEN, SAI_XCR1_SAIEN);
> +		if (ret < 0)
> +			dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
> +		break;
> +	case SNDRV_PCM_TRIGGER_SUSPEND:
> +	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> +	case SNDRV_PCM_TRIGGER_STOP:
> +		dev_dbg(cpu_dai->dev, "Disable DMA and SAI\n");
> +
> +		regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
> +				   SAI_XCR1_DMAEN,
> +				   (unsigned int)~SAI_XCR1_DMAEN);
> +
> +		ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
> +					 SAI_XCR1_SAIEN,
> +					 (unsigned int)~SAI_XCR1_SAIEN);
> +		if (ret < 0)
> +			dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static void stm32_sai_shutdown(struct snd_pcm_substream *substream,
> +			       struct snd_soc_dai *cpu_dai)
> +{
> +	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
> +
> +	regmap_update_bits(sai->regmap, STM_SAI_IMR_REGX, SAI_XIMR_MASK, 0);
> +
> +	clk_disable_unprepare(sai->sai_ck);
> +	sai->substream = NULL;
> +}
> +
> +static int stm32_sai_dai_probe(struct snd_soc_dai *cpu_dai)
> +{
> +	struct stm32_sai_sub_data *sai = dev_get_drvdata(cpu_dai->dev);
> +
> +	sai->dma_params.addr = (dma_addr_t)(sai->phys_addr + STM_SAI_DR_REGX);
> +	sai->dma_params.maxburst = 1;
> +	/* Buswidth will be set by framework at runtime */
> +	sai->dma_params.addr_width = DMA_SLAVE_BUSWIDTH_UNDEFINED;
> +
> +	if (STM_SAI_IS_PLAYBACK(sai))
> +		snd_soc_dai_init_dma_data(cpu_dai, &sai->dma_params, NULL);
> +	else
> +		snd_soc_dai_init_dma_data(cpu_dai, NULL, &sai->dma_params);
> +
> +	return 0;
> +}
> +
> +static const struct snd_soc_dai_ops stm32_sai_pcm_dai_ops = {
> +	.set_sysclk	= stm32_sai_set_sysclk,
> +	.set_fmt	= stm32_sai_set_dai_fmt,
> +	.set_tdm_slot	= stm32_sai_set_dai_tdm_slot,
> +	.startup	= stm32_sai_startup,
> +	.hw_params	= stm32_sai_hw_params,
> +	.trigger	= stm32_sai_trigger,
> +	.shutdown	= stm32_sai_shutdown,
> +};
> +
> +static const struct snd_pcm_hardware stm32_sai_pcm_hw = {
> +	.info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP,
> +	.buffer_bytes_max = 8 * PAGE_SIZE,
> +	.period_bytes_min = 1024, /* 5ms at 48kHz */
> +	.period_bytes_max = PAGE_SIZE,
> +	.periods_min = 2,
> +	.periods_max = 8,
> +};
> +
> +static struct snd_soc_dai_driver stm32_sai_playback_dai[] = {
> +{
> +		.probe = stm32_sai_dai_probe,
> +		.id = 1, /* avoid call to fmt_single_name() */
> +		.playback = {
> +			.channels_min = 1,
> +			.channels_max = 2,
> +			.rate_min = 8000,
> +			.rate_max = 192000,
> +			.rates = SNDRV_PCM_RATE_CONTINUOUS,
> +			/* DMA does not support 24 bits transfers */
> +			.formats =
> +				SNDRV_PCM_FMTBIT_S8 |
> +				SNDRV_PCM_FMTBIT_S16_LE |
> +				SNDRV_PCM_FMTBIT_S32_LE,
> +		},
> +		.ops = &stm32_sai_pcm_dai_ops,
> +	}
> +};
> +
> +static struct snd_soc_dai_driver stm32_sai_capture_dai[] = {
> +{
> +		.probe = stm32_sai_dai_probe,
> +		.id = 1, /* avoid call to fmt_single_name() */
> +		.capture = {
> +			.channels_min = 1,
> +			.channels_max = 2,
> +			.rate_min = 8000,
> +			.rate_max = 192000,
> +			.rates = SNDRV_PCM_RATE_CONTINUOUS,
> +			/* DMA does not support 24 bits transfers */
> +			.formats =
> +				SNDRV_PCM_FMTBIT_S8 |
> +				SNDRV_PCM_FMTBIT_S16_LE |
> +				SNDRV_PCM_FMTBIT_S32_LE,
> +		},
> +		.ops = &stm32_sai_pcm_dai_ops,
> +	}
> +};
> +
> +static const struct snd_dmaengine_pcm_config stm32_sai_pcm_config = {
> +	.pcm_hardware	= &stm32_sai_pcm_hw,
> +	.prepare_slave_config	= snd_dmaengine_pcm_prepare_slave_config,
> +};
> +
> +static const struct snd_soc_component_driver stm32_component = {
> +	.name = "stm32-sai",
> +};
> +
> +static const struct of_device_id stm32_sai_sub_ids[] = {
> +	{ .compatible = "st,stm32-sai-sub-a",
> +	  .data = (void *)STM_SAI_A_ID},
> +	{ .compatible = "st,stm32-sai-sub-b",
> +	  .data = (void *)STM_SAI_B_ID},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, stm32_sai_sub_ids);
> +
> +static int stm32_sai_sub_parse_of(struct platform_device *pdev,
> +				  struct stm32_sai_sub_data *sai)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct resource *res;
> +	void __iomem *base;
> +
> +	if (!np)
> +		return -ENODEV;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> +	dev_err(&pdev->dev, "res %pr\n", res);

should be dev_dbg() or removed?

> +
> +	base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	sai->phys_addr = res->start;
> +	sai->regmap = devm_regmap_init_mmio(&pdev->dev, base,
> +					    &stm32_sai_sub_regmap_config);
> +
> +	/* Get direction property */
> +	if (of_property_match_string(np, "dma-names", "tx") >= 0) {
> +		sai->dir = SNDRV_PCM_STREAM_PLAYBACK;
> +	} else if (of_property_match_string(np, "dma-names", "rx") >= 0) {
> +		sai->dir = SNDRV_PCM_STREAM_CAPTURE;
> +	} else {
> +		dev_err(&pdev->dev, "Unsupported direction\n");
> +		return -EINVAL;
> +	}
> +
> +	sai->sai_ck = devm_clk_get(&pdev->dev, "sai_ck");
> +	if (IS_ERR(sai->sai_ck)) {
> +		dev_err(&pdev->dev, "missing kernel clock sai_ck\n");
> +		return PTR_ERR(sai->sai_ck);
> +	}
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_sub_dais_init(struct platform_device *pdev,
> +				   struct stm32_sai_sub_data *sai)
> +{
> +	sai->cpu_dai_drv = devm_kzalloc(&pdev->dev,
> +					sizeof(struct snd_soc_dai_driver),
> +					GFP_KERNEL);
> +	if (!sai->cpu_dai_drv)
> +		return -ENOMEM;
> +
> +	sai->cpu_dai_drv->name = dev_name(&pdev->dev);
> +	if (STM_SAI_IS_PLAYBACK(sai)) {
> +		memcpy(sai->cpu_dai_drv, &stm32_sai_playback_dai,
> +		       sizeof(stm32_sai_playback_dai));
> +		sai->cpu_dai_drv->playback.stream_name = sai->cpu_dai_drv->name;
> +	} else {
> +		memcpy(sai->cpu_dai_drv, &stm32_sai_capture_dai,
> +		       sizeof(stm32_sai_capture_dai));
> +		sai->cpu_dai_drv->capture.stream_name = sai->cpu_dai_drv->name;
> +	}
> +
> +	return 0;
> +}
> +
> +static int stm32_sai_sub_probe(struct platform_device *pdev)
> +{
> +	struct stm32_sai_sub_data *sai;
> +	const struct of_device_id *of_id;
> +	int ret;
> +
> +	sai = devm_kzalloc(&pdev->dev, sizeof(*sai), GFP_KERNEL);
> +	if (!sai)
> +		return -ENOMEM;
> +
> +	of_id = of_match_device(stm32_sai_sub_ids, &pdev->dev);
> +	if (!of_id)
> +		return -EINVAL;
> +	sai->id = (uintptr_t)of_id->data;
> +
> +	sai->pdev = pdev;
> +	platform_set_drvdata(pdev, sai);
> +
> +	sai->pdata = dev_get_drvdata(pdev->dev.parent);
> +	if (!sai->pdata) {
> +		dev_err(&pdev->dev, "Parent device data not available\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = stm32_sai_sub_parse_of(pdev, sai);
> +	if (ret)
> +		return ret;
> +
> +	ret = stm32_sai_sub_dais_init(pdev, sai);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_request_irq(&pdev->dev, sai->pdata->irq, stm32_sai_isr,
> +			       IRQF_SHARED, dev_name(&pdev->dev), sai);
> +	if (ret) {
> +		dev_err(&pdev->dev, "irq request returned %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = devm_snd_soc_register_component(&pdev->dev, &stm32_component,
> +					      sai->cpu_dai_drv, 1);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_snd_dmaengine_pcm_register(&pdev->dev,
> +					      &stm32_sai_pcm_config, 0);
> +	if (ret) {
> +		dev_err(&pdev->dev, "could not register pcm dma\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct platform_driver stm32_sai_sub_driver = {
> +	.driver = {
> +		.name = "st,stm32-sai-sub",
> +		.of_match_table = stm32_sai_sub_ids,
> +	},
> +	.probe = stm32_sai_sub_probe,
> +};
> +
> +module_platform_driver(stm32_sai_sub_driver);
> +
> +MODULE_DESCRIPTION("STM32 Soc SAI sub-block Interface");
> +MODULE_AUTHOR("Olivier Moysan, <olivier.moysan at st.com>");

, after name?

> +MODULE_ALIAS("platform:st,stm32-sai-sub");
> +MODULE_LICENSE("GPL v2");
> 

-- 

Peter Meerwald-Stadler
Mobile: +43 664 24 44 418


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