samples: drivers: i2s: echo: Add MAX9867 codec support

Add MAX9867 codec initialization support to the sample
to later use for MAX32655FTHR support

Signed-off-by: Anuj Pathak <anuj@croxel.com>

Author: cx-anuj-pathak

samples/drivers/i2s/echo/Kconfig

@@ -1,10 +1,12 @@
 # Copyright (c) 2021 Nordic Semiconductor ASA
+# Copyright (c) 2025 Croxel Inc.
 # SPDX-License-Identifier: Apache-2.0
 
 source "Kconfig.zephyr"
 
 config I2C
-	default $(dt_compat_on_bus,$(DT_COMPAT_WOLFSON_WM8731),i2c)
+	default $(dt_compat_on_bus,$(DT_COMPAT_WOLFSON_WM8731),i2c) \
+		|| $(dt_compat_on_bus,$(DT_COMPAT_ADI_MAX9867),i2c)
 
 config TOGGLE_ECHO_EFFECT_SW0
 	bool "Toggle echo effect when pressing sw0"

samples/drivers/i2s/echo/dts/bindings/adi,max9867.yaml

@@ -0,0 +1,12 @@
+# Copyright (c) 2025 Croxel Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+# This binding has been added solely for the purpose of the overlay files used
+# in the drivers/i2s/output sample. That's why it is located in this sample source
+# directory. It can be moved and made available more widely if the need arises.
+
+description: MAX9867 Audio CODEC
+
+compatible: "adi,max9867"
+
+include: i2c-device.yaml

samples/drivers/i2s/echo/src/codec.c

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2021 Nordic Semiconductor ASA
+ * Copyright (c) 2021 Croxel Inc
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -123,3 +124,184 @@ bool init_wm8731_i2c(void)
 }
 
 #endif /* DT_ON_BUS(WM8731_NODE, i2c) */
+
+#if DT_ON_BUS(MAX9867_NODE, i2c)
+
+#define MAX9867_I2C_NODE             DT_BUS(MAX9867_NODE)
+#define MAX9867_I2C_ADDR             DT_REG_ADDR(MAX9867_NODE)
+/* Register addresses */
+#define MAX9867_00_STATUS            0x00
+#define MAX9867_01_JACKSENSE         0x01
+#define MAX9867_02_AUX_HIGH          0x02
+#define MAX9867_03_AUX_LOW           0x03
+#define MAX9867_04_INT_EN            0x04
+#define MAX9867_05_SYS_CLK           0x05
+#define MAX9867_06_CLK_HIGH          0x06
+#define MAX9867_07_CLK_LOW           0x07
+#define MAX9867_08_DAI_FORMAT        0x08
+#define MAX9867_09_DAI_CLOCK         0x09
+#define MAX9867_0A_DIG_FILTER        0x0A
+#define MAX9867_0B_SIDETONE          0x0B
+#define MAX9867_0C_LVL_DAC           0x0C
+#define MAX9867_0D_LVL_ADC           0x0D
+#define MAX9867_0E_LVL_LINE_IN_LEFT  0x0E
+#define MAX9867_0F_LVL_LINE_IN_RIGHT 0x0F
+#define MAX9867_10_VOL_LEFT          0x10
+#define MAX9867_11_VOL_RIGHT         0x11
+#define MAX9867_12_MIC_GAIN_LEFT     0x12
+#define MAX9867_13_MIC_GAIN_RIGHT    0x13
+#define MAX9867_14_ADC_INPUT         0x14
+#define MAX9867_15_MIC               0x15
+#define MAX9867_16_MODE              0x16
+#define MAX9867_17_PWR_SYS           0x17
+#define MAX9867_FF_REV_ID            0xFF
+
+/* MAX9867_04_INT_EN */
+#define MAX9867_ICLD   (1 << 7)
+#define MAX9867_SDODLY (1 << 2)
+
+/* MAX9867_05_SYS_CLK */
+#define MAX9867_PSCLK_POS 4
+
+/* MAX9867_06_CLK_HIGH */
+#define MAX9867_PLL              (1 << 7)
+#define MAX9867_NI_UPPER_8KHZ    0x10
+#define MAX9867_NI_UPPER_16KHZ   0x20
+#define MAX9867_NI_UPPER_24KHZ   0x30
+#define MAX9867_NI_UPPER_32KHZ   0x40
+#define MAX9867_NI_UPPER_44p1KHZ 0x58
+#define MAX9867_NI_UPPER_48KHZ   0x60
+
+/* MAX9867_07_CLK_LOW */
+#define MAX9867_NI_LOWER_OTHER   0x00
+#define MAX9867_NI_LOWER_44p1KHZ 0x33
+
+/* MAX9867_08_DAI_FORMAT */
+#define MAX9867_MAS    (1 << 7)
+#define MAX9867_WCI    (1 << 6)
+#define MAX9867_BCI    (1 << 5)
+#define MAX9867_DLY    (1 << 4)
+#define MAX9867_HIZOFF (1 << 3)
+#define MAX9867_TDM    (1 << 2)
+
+/* MAX9867_09_DAI_CLOCK */
+#define MAX9867_BSEL_PCLK_DIV8 0x06
+
+/* MAX9867_0D_LVL_ADC */
+#define MAX9867_AVL_POS 4
+#define MAX9867_AVR_POS 0
+
+/* MAX9867_0E_LVL_LINE_IN_LEFT
+ * MAX9867_0F_LVL_LINE_IN_RIGHT */
+#define MAX9867_LI_MUTE     (1 << 6)
+#define MAX9867_LI_GAIN_POS 0
+
+/* MAX9867_10_VOL_LEFT
+ * MAX9867_11_VOL_RIGHT */
+#define MAX9867_VOL_POS 0
+
+/* MAX9867_14_ADC_INPUT */
+#define MAX9867_MXINL_POS       6
+#define MAX9867_MXINR_POS       4
+#define MAX9867_MXIN_DIS        0
+#define MAX9867_MXIN_ANALOG_MIC 1
+#define MAX9867_MXIN_LINE       2
+
+/* MAX9867_15_MIC */
+#define MAX9867_MICCLK_POS  6
+#define MAX9867_DIGMICL_POS 5
+#define MAX9867_DIGMICR_POS 4
+
+/* MAX9867_16_MODE */
+#define MAX9867_HPMODE_POS          0
+#define MAX9867_STEREO_SE_CLICKLESS 4
+#define MAX9867_MONO_SE_CLICKLESS   5
+
+/* MAX9867_17_PWR_SYS */
+#define MAX9867_SHDN  (1 << 7)
+#define MAX9867_LNLEN (1 << 6)
+#define MAX9867_LNREN (1 << 5)
+#define MAX9867_DALEN (1 << 3)
+#define MAX9867_DAREN (1 << 2)
+#define MAX9867_ADLEN (1 << 1)
+#define MAX9867_ADREN (1 << 0)
+
+bool init_max9867_i2c(void)
+{
+	const struct device *const i2c_dev = DEVICE_DT_GET(MAX9867_I2C_NODE);
+
+	/* Initialization data for MAX9867 registers. */
+	static const uint8_t init[][2] = {
+		/* Shutdown MAX9867 during configuration */
+		{MAX9867_17_PWR_SYS, 0x00},
+		/* Clear all regs to POR state. The MAX9867 does not not have an external
+		 * reset signal. So manually writing 0, from (0x04 - 0x17)
+		 */
+		{MAX9867_04_INT_EN, 0x00},
+		{MAX9867_05_SYS_CLK, 0x00},
+		{MAX9867_06_CLK_HIGH, 0x00},
+		{MAX9867_07_CLK_LOW, 0x00},
+		{MAX9867_08_DAI_FORMAT, 0x00},
+		{MAX9867_09_DAI_CLOCK, 0x00},
+		{MAX9867_0A_DIG_FILTER, 0x00},
+		{MAX9867_0B_SIDETONE, 0x00},
+		{MAX9867_0C_LVL_DAC, 0x00},
+		{MAX9867_0D_LVL_ADC, 0x00},
+		{MAX9867_0E_LVL_LINE_IN_LEFT, 0x00},
+		{MAX9867_0F_LVL_LINE_IN_RIGHT, 0x00},
+		{MAX9867_10_VOL_LEFT, 0x00},
+		{MAX9867_11_VOL_RIGHT, 0x00},
+		{MAX9867_12_MIC_GAIN_LEFT, 0x00},
+		{MAX9867_13_MIC_GAIN_RIGHT, 0x00},
+		{MAX9867_14_ADC_INPUT, 0x00},
+		{MAX9867_15_MIC, 0x00},
+		{MAX9867_16_MODE, 0x00},
+		{MAX9867_17_PWR_SYS, 0x00},
+		/* Select MCLK prescaler. PSCLK divides MCLK to generate a PCLK between 10MHz and
+		 * 20MHz. Set prescaler, FREQ field is 0 for Normal or PLL mode, < 20MHz.
+		 */
+		{MAX9867_05_SYS_CLK, 0x01 << MAX9867_PSCLK_POS},
+		/* Configure codec to generate 48kHz sampling frequency in master mode */
+		{MAX9867_06_CLK_HIGH, MAX9867_NI_UPPER_44p1KHZ},
+		{MAX9867_07_CLK_LOW, MAX9867_NI_LOWER_44p1KHZ},
+		{MAX9867_09_DAI_CLOCK, MAX9867_BSEL_PCLK_DIV8},
+		/* I2S format */
+		{MAX9867_08_DAI_FORMAT, MAX9867_MAS | MAX9867_DLY | MAX9867_HIZOFF},
+		/* */
+		{MAX9867_0A_DIG_FILTER, 0xA2},
+		/* Select Digital microphone input */
+		{MAX9867_15_MIC, ((0x1 << MAX9867_DIGMICR_POS))},
+		/* ADC level */
+		{MAX9867_0D_LVL_ADC, (3 << MAX9867_AVL_POS) | (3 << MAX9867_AVR_POS)},
+		/*Set line-in level, disconnect line input from playback amplifiers */
+		{MAX9867_0E_LVL_LINE_IN_LEFT, (0x0C << MAX9867_LI_GAIN_POS) | MAX9867_LI_MUTE},
+		{MAX9867_0F_LVL_LINE_IN_RIGHT, (0x0C << MAX9867_LI_GAIN_POS) | MAX9867_LI_MUTE},
+		/* Headphone mode */
+		{MAX9867_16_MODE, MAX9867_STEREO_SE_CLICKLESS << MAX9867_HPMODE_POS},
+		/* Set playback volume */
+		{MAX9867_10_VOL_LEFT, 0x04 << MAX9867_VOL_POS},
+		{MAX9867_11_VOL_RIGHT, 0x04 << MAX9867_VOL_POS},
+		/* Enable */
+		{MAX9867_17_PWR_SYS, MAX9867_SHDN | MAX9867_DALEN | MAX9867_DAREN | MAX9867_ADLEN},
+	};
+
+	if (!device_is_ready(i2c_dev)) {
+		printk("%s is not ready\n", i2c_dev->name);
+		return false;
+	}
+
+	for (int i = 0; i < ARRAY_SIZE(init); ++i) {
+		const uint8_t *entry = init[i];
+		int ret;
+
+		ret = i2c_reg_write_byte(i2c_dev, MAX9867_I2C_ADDR, entry[0], entry[1]);
+		if (ret < 0) {
+			printk("Initialization step %d failed with %d\n", i, ret);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+#endif /* DT_ON_BUS(MAX9867_NODE, i2c) */

samples/drivers/i2s/echo/src/codec.h

@@ -1,11 +1,17 @@
 /*
  * Copyright (c) 2021 Nordic Semiconductor ASA
+ * Copyright (c) 2025 Croxel Inc
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #define WM8731_NODE DT_NODELABEL(wm8731)
+#define MAX9867_NODE DT_NODELABEL(max9867)
 
 #if DT_ON_BUS(WM8731_NODE, i2c)
 bool init_wm8731_i2c(void);
 #endif
+
+#if DT_ON_BUS(MAX9867_NODE, i2c)
+bool init_max9867_i2c(void);
+#endif

samples/drivers/i2s/echo/src/main.c

@@ -258,6 +258,12 @@ int main(void)
 	}
 #endif
 
+#if DT_ON_BUS(MAX9867_NODE, i2c)
+	if (!init_max9867_i2c()) {
+		return 0;
+	}
+#endif
+
 	if (!init_buttons()) {
 		return 0;
 	}