ASoC: tegra: Add Tegra186 based DSPK driver

The Digital Speaker Controller (DSPK) converts the multi-bit Pulse Code
Modulation (PCM) audio input to oversampled 1-bit Pulse Density Modulation
(PDM) output. From the signal flow perpsective, the DSPK can be viewed as
a PDM transmitter that up-samples the input to the desired sampling rate
by interpolation then converts the oversampled PCM input to the desired
1-bit output via Delta Sigma Modulation (DSM).

This patch registers DSPK component with ASoC framework. The component
driver exposes DAPM widgets, routes and kcontrols for the device. The DAI
driver exposes DSPK interfaces, which can be used to connect different
components in the ASoC layer. Makefile and Kconfig support is added to
allow to build the driver. The DSPK devices can be enabled in the DT via
"nvidia,tegra186-dspk" compatible binding. This driver can be used
on Tegra194 chip as well.
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Link: https://lore.kernel.org/r/1595134890-16470-7-git-send-email-spujar@nvidia.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/tegra/Kconfig

@@ -93,6 +93,19 @@ config SND_SOC_TEGRA210_I2S
 	  compatible devices.
 	  Say Y or M if you want to add support for Tegra210 I2S module.
 
+config SND_SOC_TEGRA186_DSPK
+	tristate "Tegra186 DSPK module"
+	depends on SND_SOC_TEGRA
+	help
+	  Config to enable the Digital Speaker Controller (DSPK) which
+	  converts the multi-bit Pulse Code Modulation (PCM) audio input to
+	  oversampled 1-bit Pulse Density Modulation (PDM) output. From the
+	  signal flow perspective DSPK can be viewed as a PDM transmitter
+	  that up-samples the input to the desired sampling rate by
+	  interpolation and then converts the oversampled PCM input to
+	  the desired 1-bit output via Delta Sigma Modulation (DSM).
+	  Say Y or M if you want to add support for Tegra186 DSPK module.
+
 config SND_SOC_TEGRA_RT5640
 	tristate "SoC Audio support for Tegra boards using an RT5640 codec"
 	depends on SND_SOC_TEGRA && I2C && GPIOLIB

sound/soc/tegra/Makefile

@@ -11,6 +11,7 @@ snd-soc-tegra30-i2s-objs := tegra30_i2s.o
 snd-soc-tegra210-ahub-objs := tegra210_ahub.o
 snd-soc-tegra210-dmic-objs := tegra210_dmic.o
 snd-soc-tegra210-i2s-objs := tegra210_i2s.o
+snd-soc-tegra186-dspk-objs := tegra186_dspk.o
 
 obj-$(CONFIG_SND_SOC_TEGRA) += snd-soc-tegra-pcm.o
 obj-$(CONFIG_SND_SOC_TEGRA) += snd-soc-tegra-utils.o
@@ -23,6 +24,7 @@ obj-$(CONFIG_SND_SOC_TEGRA30_I2S) += snd-soc-tegra30-i2s.o
 obj-$(CONFIG_SND_SOC_TEGRA210_DMIC) += snd-soc-tegra210-dmic.o
 obj-$(CONFIG_SND_SOC_TEGRA210_AHUB) += snd-soc-tegra210-ahub.o
 obj-$(CONFIG_SND_SOC_TEGRA210_I2S) += snd-soc-tegra210-i2s.o
+obj-$(CONFIG_SND_SOC_TEGRA186_DSPK) += snd-soc-tegra186-dspk.o
 
 # Tegra machine Support
 snd-soc-tegra-rt5640-objs := tegra_rt5640.o

sound/soc/tegra/tegra186_dspk.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * tegra186_dspk.h - Definitions for Tegra186 DSPK driver
+ *
+ * Copyright (c) 2020 NVIDIA CORPORATION. All rights reserved.
+ *
+ */
+
+#ifndef __TEGRA186_DSPK_H__
+#define __TEGRA186_DSPK_H__
+
+/* Register offsets from DSPK BASE */
+#define TEGRA186_DSPK_RX_STATUS			0x0c
+#define TEGRA186_DSPK_RX_INT_STATUS		0x10
+#define TEGRA186_DSPK_RX_INT_MASK		0x14
+#define TEGRA186_DSPK_RX_INT_SET		0x18
+#define TEGRA186_DSPK_RX_INT_CLEAR		0x1c
+#define TEGRA186_DSPK_RX_CIF_CTRL		0x20
+#define TEGRA186_DSPK_ENABLE			0x40
+#define TEGRA186_DSPK_SOFT_RESET		0x44
+#define TEGRA186_DSPK_CG			0x48
+#define TEGRA186_DSPK_STATUS			0x4c
+#define TEGRA186_DSPK_INT_STATUS		0x50
+#define TEGRA186_DSPK_CORE_CTRL			0x60
+#define TEGRA186_DSPK_CODEC_CTRL		0x64
+
+/* DSPK CORE CONTROL fields */
+#define CH_SEL_SHIFT				8
+#define TEGRA186_DSPK_CHANNEL_SELECT_MASK	(0x3 << CH_SEL_SHIFT)
+#define DSPK_OSR_SHIFT				4
+#define TEGRA186_DSPK_OSR_MASK			(0x3 << DSPK_OSR_SHIFT)
+#define LRSEL_POL_SHIFT				0
+#define TEGRA186_DSPK_CTRL_LRSEL_POLARITY_MASK	(0x1 << LRSEL_POL_SHIFT)
+#define TEGRA186_DSPK_RX_FIFO_DEPTH		64
+
+#define DSPK_OSR_FACTOR				32
+
+/* DSPK interface clock ratio */
+#define DSPK_CLK_RATIO				4
+
+enum tegra_dspk_osr {
+	DSPK_OSR_32,
+	DSPK_OSR_64,
+	DSPK_OSR_128,
+	DSPK_OSR_256,
+};
+
+enum tegra_dspk_ch_sel {
+	DSPK_CH_SELECT_LEFT,
+	DSPK_CH_SELECT_RIGHT,
+	DSPK_CH_SELECT_STEREO,
+};
+
+enum tegra_dspk_lrsel {
+	DSPK_LRSEL_LEFT,
+	DSPK_LRSEL_RIGHT,
+};
+
+struct tegra186_dspk {
+	unsigned int rx_fifo_th;
+	unsigned int osr_val;
+	unsigned int lrsel;
+	unsigned int ch_sel;
+	unsigned int mono_to_stereo;
+	unsigned int stereo_to_mono;
+	struct clk *clk_dspk;
+	struct regmap *regmap;
+};
+
+#endif