ASoC: tegra: Add Tegra210 based DMIC driver

The Digital MIC (DMIC) Controller is used to interface with Pulse Density
Modulation (PDM) input devices. The DMIC controller implements a converter
to convert PDM signals to Pulse Code Modulation (PCM) signals. From signal
flow perspective, the DMIC can be viewed as a PDM receiver.

This patch registers DMIC component with ASoC framework. The component
driver exposes DAPM widgets, routes and kcontrols for the device. The DAI
driver exposes DMIC 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 DMIC devices can be enabled in the DT via
"nvidia,tegra210-dmic" compatible string. This driver can be used for
Tegra186 and Tegra194 chips as well.
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Link: https://lore.kernel.org/r/1595134890-16470-4-git-send-email-spujar@nvidia.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/tegra/Kconfig

@@ -62,6 +62,17 @@ config SND_SOC_TEGRA30_I2S
 	  Tegra30 I2S interface. You will also need to select the individual
 	  machine drivers to support below.
 
+config SND_SOC_TEGRA210_DMIC
+	tristate "Tegra210 DMIC module"
+	depends on SND_SOC_TEGRA
+	help
+	  Config to enable the Digital MIC (DMIC) controller which is used
+	  to interface with Pulse Density Modulation (PDM) input devices.
+	  The DMIC controller implements a converter to convert PDM signals
+	  to Pulse Code Modulation (PCM) signals. This can be viewed as a
+	  PDM receiver.
+	  Say Y or M if you want to add support for Tegra210 DMIC 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

@@ -8,6 +8,7 @@ snd-soc-tegra20-i2s-objs := tegra20_i2s.o
 snd-soc-tegra20-spdif-objs := tegra20_spdif.o
 snd-soc-tegra30-ahub-objs := tegra30_ahub.o
 snd-soc-tegra30-i2s-objs := tegra30_i2s.o
+snd-soc-tegra210-dmic-objs := tegra210_dmic.o
 
 obj-$(CONFIG_SND_SOC_TEGRA) += snd-soc-tegra-pcm.o
 obj-$(CONFIG_SND_SOC_TEGRA) += snd-soc-tegra-utils.o
@@ -17,6 +18,7 @@ obj-$(CONFIG_SND_SOC_TEGRA20_I2S) += snd-soc-tegra20-i2s.o
 obj-$(CONFIG_SND_SOC_TEGRA20_SPDIF) += snd-soc-tegra20-spdif.o
 obj-$(CONFIG_SND_SOC_TEGRA30_AHUB) += snd-soc-tegra30-ahub.o
 obj-$(CONFIG_SND_SOC_TEGRA30_I2S) += snd-soc-tegra30-i2s.o
+obj-$(CONFIG_SND_SOC_TEGRA210_DMIC) += snd-soc-tegra210-dmic.o
 
 # Tegra machine Support
 snd-soc-tegra-rt5640-objs := tegra_rt5640.o

sound/soc/tegra/tegra210_dmic.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * tegra210_dmic.h - Definitions for Tegra210 DMIC driver
+ *
+ * Copyright (c) 2020 NVIDIA CORPORATION.  All rights reserved.
+ *
+ */
+
+#ifndef __TEGRA210_DMIC_H__
+#define __TEGRA210_DMIC_H__
+
+/* Register offsets from DMIC BASE */
+#define TEGRA210_DMIC_TX_STATUS				0x0c
+#define TEGRA210_DMIC_TX_INT_STATUS			0x10
+#define TEGRA210_DMIC_TX_INT_MASK			0x14
+#define TEGRA210_DMIC_TX_INT_SET			0x18
+#define TEGRA210_DMIC_TX_INT_CLEAR			0x1c
+#define TEGRA210_DMIC_TX_CIF_CTRL			0x20
+#define TEGRA210_DMIC_ENABLE				0x40
+#define TEGRA210_DMIC_SOFT_RESET			0x44
+#define TEGRA210_DMIC_CG				0x48
+#define TEGRA210_DMIC_STATUS				0x4c
+#define TEGRA210_DMIC_INT_STATUS			0x50
+#define TEGRA210_DMIC_CTRL				0x64
+#define TEGRA210_DMIC_DBG_CTRL				0x70
+#define TEGRA210_DMIC_DCR_BIQUAD_0_COEF_4		0x88
+#define TEGRA210_DMIC_LP_FILTER_GAIN			0x8c
+#define TEGRA210_DMIC_LP_BIQUAD_0_COEF_0		0x90
+#define TEGRA210_DMIC_LP_BIQUAD_0_COEF_1		0x94
+#define TEGRA210_DMIC_LP_BIQUAD_0_COEF_2		0x98
+#define TEGRA210_DMIC_LP_BIQUAD_0_COEF_3		0x9c
+#define TEGRA210_DMIC_LP_BIQUAD_0_COEF_4		0xa0
+#define TEGRA210_DMIC_LP_BIQUAD_1_COEF_0		0xa4
+#define TEGRA210_DMIC_LP_BIQUAD_1_COEF_1		0xa8
+#define TEGRA210_DMIC_LP_BIQUAD_1_COEF_2		0xac
+#define TEGRA210_DMIC_LP_BIQUAD_1_COEF_3		0xb0
+#define TEGRA210_DMIC_LP_BIQUAD_1_COEF_4		0xb4
+
+/* Fields in TEGRA210_DMIC_CTRL */
+#define CH_SEL_SHIFT					8
+#define TEGRA210_DMIC_CTRL_CHANNEL_SELECT_MASK		(0x3 << CH_SEL_SHIFT)
+#define LRSEL_POL_SHIFT					4
+#define TEGRA210_DMIC_CTRL_LRSEL_POLARITY_MASK		(0x1 << LRSEL_POL_SHIFT)
+#define OSR_SHIFT					0
+#define TEGRA210_DMIC_CTRL_OSR_MASK			(0x3 << OSR_SHIFT)
+
+#define DMIC_OSR_FACTOR					64
+
+#define DEFAULT_GAIN_Q23				0x800000
+
+/* Max boost gain factor used for mixer control */
+#define MAX_BOOST_GAIN 25599
+
+enum tegra_dmic_ch_select {
+	DMIC_CH_SELECT_LEFT,
+	DMIC_CH_SELECT_RIGHT,
+	DMIC_CH_SELECT_STEREO,
+};
+
+enum tegra_dmic_osr {
+	DMIC_OSR_64,
+	DMIC_OSR_128,
+	DMIC_OSR_256,
+};
+
+enum tegra_dmic_lrsel {
+	DMIC_LRSEL_LEFT,
+	DMIC_LRSEL_RIGHT,
+};
+
+struct tegra210_dmic {
+	struct clk *clk_dmic;
+	struct regmap *regmap;
+	unsigned int mono_to_stereo;
+	unsigned int stereo_to_mono;
+	unsigned int boost_gain;
+	unsigned int ch_select;
+	unsigned int osr_val;
+	unsigned int lrsel;
+};
+
+#endif