drivers: dac: added driver for Microchip MCP4725

The MCP4725 is a single channel 12 bit DAC. It is controlled via I2C.

Signed-off-by: Kieran Mackey <kieran.mackey@lairdconnect.com>

drivers/dac/CMakeLists.txt

@@ -9,4 +9,5 @@ zephyr_library_sources_ifdef(CONFIG_DAC_SAM0		dac_sam0.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_DACX0508	dac_dacx0508.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_DACX3608	dac_dacx3608.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_SHELL		dac_shell.c)
+zephyr_library_sources_ifdef(CONFIG_DAC_MCP4725		dac_mcp4725.c)
 zephyr_library_sources_ifdef(CONFIG_USERSPACE		dac_handlers.c)

drivers/dac/Kconfig

@@ -34,4 +34,6 @@ source "drivers/dac/Kconfig.dacx0508"
 
 source "drivers/dac/Kconfig.dacx3608"
 
+source "drivers/dac/Kconfig.mcp4725"
+
 endif # DAC

drivers/dac/Kconfig.mcp4725

@@ -0,0 +1,21 @@
+# DAC configuration options
+
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config DAC_MCP4725
+	bool "Microchip MCP4725 DAC driver"
+	depends on I2C
+	help
+	  Enable the driver for the Microchip MCP4725.
+
+if DAC_MCP4725
+
+config DAC_MCP4725_INIT_PRIORITY
+	int "Init priority"
+	default 80
+	help
+	  MCP4725 DAC device driver initialization priority.
+
+endif # DAC_MCP4725

drivers/dac/dac_mcp4725.c

@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#define DT_DRV_COMPAT microchip_mcp4725
+
+#include <zephyr.h>
+#include <drivers/i2c.h>
+#include <drivers/dac.h>
+#include <logging/log.h>
+
+LOG_MODULE_REGISTER(dac_mcp4725, CONFIG_DAC_LOG_LEVEL);
+
+/* Information in this file comes from MCP4725 datasheet revision D
+ * found at https://ww1.microchip.com/downloads/en/DeviceDoc/22039d.pdf
+ */
+
+/* Defines for field values in MCP4725 DAC register */
+#define MCP4725_DAC_MAX_VAL			0xFFF
+
+#define MCP4725_FAST_MODE_POWER_DOWN_POS	4U
+#define MCP4725_FAST_MODE_DAC_UPPER_VAL_POS	8U
+#define MCP4725_FAST_MODE_DAC_UPPER_VAL_MASK	0xF
+#define MCP4725_FAST_MODE_DAC_LOWER_VAL_MASK	0xFF
+
+#define MCP4725_READ_RDY_POS			7U
+#define MCP4725_READ_RDY_MASK			(0x1 << MCP4725_READ_RDY_POS)
+
+/* After writing eeprom, the MCP4725 can be in a busy state for 25 - 50ms
+ * See section 1.0 of MCP4725 datasheet, 'Electrical Characteristics'
+ */
+#define MCP4725_BUSY_TIMEOUT_MS			60U
+
+struct mcp4725_config {
+	const struct device *i2c_dev;
+	uint16_t i2c_addr;
+};
+
+/* Read mcp4725 and check RDY status bit */
+static int mcp4725_wait_until_ready(const struct device *dev, uint16_t i2c_addr)
+{
+	uint8_t rx_data[5];
+	bool mcp4725_ready = false;
+	int ret;
+	int32_t timeout = k_uptime_get_32() + MCP4725_BUSY_TIMEOUT_MS;
+
+	/* Wait until RDY bit is set or return error if timer exceeds MCP4725_BUSY_TIMEOUT_MS */
+	while (!mcp4725_ready) {
+		ret = i2c_read(dev, rx_data, sizeof(rx_data), i2c_addr);
+
+		if (ret == 0) {
+			mcp4725_ready = rx_data[0] & MCP4725_READ_RDY_MASK;
+		} else {
+			/* I2C error */
+			return ret;
+		}
+
+		if (k_uptime_get_32() > timeout) {
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
+/* MCP4725 is a single channel 12 bit DAC */
+static int mcp4725_channel_setup(const struct device *dev,
+				   const struct dac_channel_cfg *channel_cfg)
+{
+	if (channel_cfg->channel_id != 0) {
+		return -EINVAL;
+	}
+
+	if (channel_cfg->resolution != 12) {
+		return -ENOTSUP;
+	}
+
+	return 0;
+}
+
+static int mcp4725_write_value(const struct device *dev, uint8_t channel,
+				uint32_t value)
+{
+	const struct mcp4725_config *config = (struct mcp4725_config *)dev->config;
+	uint8_t tx_data[2];
+	int ret;
+
+	if (channel != 0) {
+		return -EINVAL;
+	}
+
+	/* Check value isn't over 12 bits */
+	if (value > MCP4725_DAC_MAX_VAL) {
+		return -ENOTSUP;
+	}
+
+	/* WRITE_MODE_FAST message format (2 bytes):
+	 *
+	 * ||     15 14     |        13 12        |    11 10 9 8    || 7 6 5 4 3 2 1 0 ||
+	 * || Fast mode (0) | Power-down bits (0) | DAC value[11:8] || DAC value[7:0]  ||
+	 */
+	tx_data[0] = ((value >> MCP4725_FAST_MODE_DAC_UPPER_VAL_POS) &
+		MCP4725_FAST_MODE_DAC_UPPER_VAL_MASK);
+	tx_data[1] = (value & MCP4725_FAST_MODE_DAC_LOWER_VAL_MASK);
+	ret = i2c_write(config->i2c_dev, tx_data, sizeof(tx_data),
+		config->i2c_addr);
+
+	return ret;
+}
+
+static int dac_mcp4725_init(const struct device *dev)
+{
+	const struct mcp4725_config *config = dev->config;
+
+	if (!device_is_ready(config->i2c_dev)) {
+		LOG_ERR("I2C device not found");
+		return -EINVAL;
+	}
+
+	/* Check we can read a 'RDY' bit from this device */
+	if (mcp4725_wait_until_ready(config->i2c_dev, config->i2c_addr)) {
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+static const struct dac_driver_api mcp4725_driver_api = {
+	.channel_setup = mcp4725_channel_setup,
+	.write_value = mcp4725_write_value,
+};
+
+
+#define INST_DT_MCP4725(index)						\
+	static const struct mcp4725_config mcp4725_config_##index = {	\
+		.i2c_dev = DEVICE_DT_GET(DT_INST_BUS(index)),		\
+		.i2c_addr = DT_INST_REG_ADDR(index)			\
+	};								\
+									\
+	DEVICE_DT_INST_DEFINE(index, dac_mcp4725_init,			\
+			    device_pm_control_nop,			\
+			    NULL,					\
+			    &mcp4725_config_##index, POST_KERNEL,	\
+			    CONFIG_DAC_MCP4725_INIT_PRIORITY,		\
+			    &mcp4725_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(INST_DT_MCP4725);

dts/bindings/dac/microchip,mcp4725.yaml

@@ -0,0 +1,15 @@
+# Copyright (c) 2021 Laird Connectivity
+# SPDX-License-Identifier: Apache-2.0
+
+description: Microchip MCP4725 12-bit DAC
+
+compatible: "microchip,mcp4725"
+
+include: [dac-controller.yaml, i2c-device.yaml]
+
+properties:
+    "#io-channel-cells":
+      const: 1
+
+io-channel-cells:
+    - output

samples/drivers/dac/README.rst

@@ -88,6 +88,48 @@ follows:
 
 DAC output is available on connector J4 pin 11.
 
+Building and Running for BL652
+======================================
+The BL652 DVK PCB contains a footprint for a MCP4725 to use as an external
+DAC. Note this is not populated by default. The sample can be built and
+executed for the :ref:`bl652_dvk` as follows:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/drivers/dac
+   :board: bl652_dvk
+   :goals: build flash
+   :compact:
+
+DAC output is available on pin 1 of the MCP4725.
+
+Building and Running for BL653
+======================================
+The BL653 DVK PCB contains a footprint for a MCP4725 to use as an external
+DAC. Note this is not populated by default. The sample can be built and
+executed for the :ref:`bl653_dvk` as follows:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/drivers/dac
+   :board: bl653_dvk
+   :goals: build flash
+   :compact:
+
+DAC output is available on pin 1 of the MCP4725.
+
+Building and Running for BL654
+======================================
+The BL654 DVK PCB contains a footprint for a MCP4725 to use as an external
+DAC. Note this is not populated by default. The sample can be built and
+executed for the :ref:`bl654_dvk` as follows:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/drivers/dac
+   :board: bl654_dvk
+   :goals: build flash
+   :compact:
+
+DAC output is available on pin 1 of the MCP4725.
+
 Sample output
 =============
 

samples/drivers/dac/boards/bl652_dvk.conf

@@ -0,0 +1,6 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_DAC_MCP4725=y

samples/drivers/dac/boards/bl652_dvk.overlay

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

samples/drivers/dac/boards/bl653_dvk.conf

@@ -0,0 +1,6 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_DAC_MCP4725=y

samples/drivers/dac/boards/bl653_dvk.overlay

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

samples/drivers/dac/boards/bl654_dvk.conf

@@ -0,0 +1,6 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_DAC_MCP4725=y

samples/drivers/dac/boards/bl654_dvk.overlay

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

samples/drivers/dac/sample.yaml

@@ -5,7 +5,8 @@ tests:
     tags: DAC
     platform_allow: |
       arduino_zero frdm_k22f frdm_k64f nucleo_f091rc nucleo_g071rb nucleo_g431rb
-      nucleo_l073rz nucleo_l152re twr_ke18f nucleo_f767zi nucleo_f429zi
+      nucleo_l073rz nucleo_l152re twr_ke18f nucleo_f767zi nucleo_f429zi bl652_dvk
+      bl653_dvk bl654_dvk
     depends_on: dac
     harness: console
     harness_config:

tests/drivers/dac/dac_api/boards/bl652_dvk.conf

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_I2C=y
+CONFIG_DAC_MCP4725=y

tests/drivers/dac/dac_api/boards/bl652_dvk.overlay

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		/* MCP4725 not populated at factory */
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

tests/drivers/dac/dac_api/boards/bl653_dvk.conf

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_I2C=y
+CONFIG_DAC_MCP4725=y

tests/drivers/dac/dac_api/boards/bl653_dvk.overlay

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		/* MCP4725 not populated at factory */
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

tests/drivers/dac/dac_api/boards/bl654_dvk.conf

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_I2C=y
+CONFIG_DAC_MCP4725=y

tests/drivers/dac/dac_api/boards/bl654_dvk.overlay

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		/* MCP4725 not populated at factory */
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

tests/drivers/dac/dac_api/src/test_dac.c

@@ -37,6 +37,16 @@
 #define DAC_RESOLUTION		12
 #define DAC_CHANNEL_ID		0
 
+#elif defined(CONFIG_BOARD_BL652_DVK) || \
+	defined(CONFIG_BOARD_BL653_DVK) || \
+	defined(CONFIG_BOARD_BL654_DVK)
+ /* Note external DAC MCP4725 is not populated on BL652_DVK, BL653_DVK and
+  * BL654_DVK at factory
+  */
+#define DAC_DEVICE_NAME		DT_LABEL(DT_NODELABEL(dac0))
+#define DAC_RESOLUTION		12
+#define DAC_CHANNEL_ID		0
+
 #else
 #error "Unsupported board."
 #endif

tests/drivers/dac/dac_api/testcase.yaml

@@ -2,5 +2,7 @@ common:
   tags: dac drivers userspace
 tests:
   drivers.dac:
-    platform_allow: frdm_k22f frdm_k64f nucleo_l073rz nucleo_l152re twr_ke18f nucleo_f767zi nucleo_f429zi
+    platform_allow:
+      frdm_k22f frdm_k64f nucleo_l073rz nucleo_l152re twr_ke18f nucleo_f767zi
+      nucleo_f429zi bl652_dvk bl653_dvk bl654_dvk
     depends_on: dac

tests/drivers/dac/dac_loopback/boards/bl652_dvk.conf

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_I2C=y
+CONFIG_DAC_MCP4725=y

tests/drivers/dac/dac_loopback/boards/bl652_dvk.overlay

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		/* MCP4725 not populated at factory */
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

tests/drivers/dac/dac_loopback/boards/bl653_dvk.conf

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_I2C=y
+CONFIG_DAC_MCP4725=y

tests/drivers/dac/dac_loopback/boards/bl653_dvk.overlay

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	dac0: mcp4725@60 {
+		/* MCP4725 not populated at factory */
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

tests/drivers/dac/dac_loopback/boards/bl654_dvk.conf

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2021 Laird Connectivity
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+CONFIG_I2C=y
+CONFIG_DAC_MCP4725=y

tests/drivers/dac/dac_loopback/boards/bl654_dvk.overlay

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2021 Laird Connectivity
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	mcp4725@60 {
+		/* MCP4725 not populated at factory */
+		compatible = "microchip,mcp4725";
+		reg = <0x60>;
+		label = "MCP4725";
+		#io-channel-cells = <1>;
+	};
+};

tests/drivers/dac/dac_loopback/src/test_dac.c

@@ -111,6 +111,28 @@
 #define ADC_ACQUISITION_TIME	ADC_ACQ_TIME_DEFAULT
 #define ADC_CHANNEL_ID		23
 
+#elif defined(CONFIG_BOARD_BL652_DVK) || \
+	defined(CONFIG_BOARD_BL653_DVK) || \
+	defined(CONFIG_BOARD_BL654_DVK)
+#include <hal/nrf_saadc.h>
+ /* DAC output from MCP4725 pin 1
+  * ADC_1 input read from pin SIO_3
+  * Note external DAC MCP4725 is not populated on BL652_DVK, BL653_DVK and
+  * BL654_DVK at factory
+  */
+
+#define DAC_DEVICE_NAME		DT_LABEL(DT_NODELABEL(dac0))
+#define DAC_RESOLUTION		12
+#define DAC_CHANNEL_ID		0
+
+#define ADC_DEVICE_NAME		DT_LABEL(DT_NODELABEL(adc))
+#define ADC_RESOLUTION		12
+#define ADC_GAIN		ADC_GAIN_1_4
+#define ADC_REFERENCE		ADC_REF_VDD_1_4
+#define ADC_ACQUISITION_TIME	ADC_ACQ_TIME_DEFAULT
+#define ADC_CHANNEL_ID		1
+#define ADC_1ST_CHANNEL_INPUT	NRF_SAADC_INPUT_AIN1
+
 #else
 #error "Unsupported board."
 #endif
@@ -125,6 +147,12 @@ static const struct adc_channel_cfg adc_ch_cfg = {
 	.reference        = ADC_REFERENCE,
 	.acquisition_time = ADC_ACQUISITION_TIME,
 	.channel_id       = ADC_CHANNEL_ID,
+
+#if defined(CONFIG_BOARD_BL652_DVK) || \
+	defined(CONFIG_BOARD_BL653_DVK) || \
+	defined(CONFIG_BOARD_BL654_DVK)
+	.input_positive   = ADC_1ST_CHANNEL_INPUT,
+#endif
 };
 
 static const struct device *init_dac(void)

tests/drivers/dac/dac_loopback/testcase.yaml

@@ -8,3 +8,4 @@ tests:
       fixture: dac_adc_loopback
     platform_allow: |
       frdm_k22f frdm_k64f nucleo_f207zg nucleo_l073rz nucleo_l152re twr_ke18f
+      bl652_dvk bl653_dvk bl654_dvk