drivers: dac: Add drivers for TI DAC family X311 on SPI bus

drivers/dac/CMakeLists.txt

@@ -34,4 +34,5 @@ zephyr_library_sources_ifdef(CONFIG_DAC_SAMD5X dac_samd5x.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_SILABS_VDAC dac_silabs_vdac.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_STM32 dac_stm32.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_TEST dac_test.c)
+zephyr_library_sources_ifdef(CONFIG_DAC_TX311 dac_tx311.c)
 # zephyr-keep-sorted-stop

drivers/dac/Kconfig

@@ -52,6 +52,7 @@ source "drivers/dac/Kconfig.samd5x"
 source "drivers/dac/Kconfig.silabs"
 source "drivers/dac/Kconfig.stm32"
 source "drivers/dac/Kconfig.test"
+source "drivers/dac/Kconfig.tx311"
 # zephyr-keep-sorted-stop
 
 endif # DAC

drivers/dac/Kconfig.tx311

@@ -0,0 +1,14 @@
+# DAC configuration options
+#
+# Copyright (c) 2025  Andreas Wolf <[email protected]>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config DAC_TX311
+	bool "TI DACx311 DAC driver"
+	default y
+	depends on DT_HAS_TI_DAC8311_ENABLED || DT_HAS_TI_DAC7311_ENABLED || \
+		DT_HAS_TI_DAC6311_ENABLED || DT_HAS_TI_DAC5311_ENABLED
+	select SPI
+	help
+	  Enable the driver for TI DACx311 chip.

drivers/dac/dac_tx311.c

@@ -0,0 +1,248 @@
+/*
+ * Copyright (c) 2025  Andreas Wolf <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file  dac_tx311.c
+ * @brief Driver for the TI x311 single channel DAC chips.
+ *
+ * This driver supports multiple variants of the Texas Instrument DAC chip.
+ *
+ *  DAC5311 : 8-bit resolution
+ *  DAC6311 : 10-bit resolution
+ *  DAC7311 : 12-bit resolution
+ *  DAC8311 : 14-bit resolution
+ *
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/spi.h>
+#include <zephyr/drivers/dac.h>
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(dac_tx311, CONFIG_DAC_LOG_LEVEL);
+
+#define DACX311_MIN_RESOLUTION 8U
+#define DACX311_MAX_RESOLUTION 14U
+
+#define DAC8311_RESOLUTION     14U
+#define DAC7311_RESOLUTION     12U
+#define DAC6311_RESOLUTION     10U
+#define DAC5311_RESOLUTION     8U
+
+#define DACX311_MAX_CHANNEL    1U
+
+#define DACX311_SPI_HZ_MAX     (5*1000*1000)
+
+struct dacx311_config {
+	struct spi_dt_spec bus;
+	uint8_t  resolution;
+	uint8_t  power_down_mode;
+};
+
+struct dacx311_data {
+	uint8_t resolution;
+	uint16_t power_down_mode;
+	uint8_t configured;
+};
+
+static int dacx311_reg_write(const struct device *dev, uint16_t val)
+{
+	const struct dacx311_config *cfg = dev->config;
+	uint8_t tx_bytes[2];
+
+	/* Construct write buffer for SPI API */
+	const struct spi_buf tx_buf[1] = {
+		{
+			.buf = tx_bytes,
+			.len = sizeof(tx_bytes)
+		}
+	};
+	const struct spi_buf_set tx = {
+		.buffers = tx_buf,
+		.count = ARRAY_SIZE(tx_buf)
+	};
+
+	/* Set register bits */
+	tx_bytes[0] = val >> 8;
+	tx_bytes[1] = val & 0xFF;
+
+	/* Write to bus */
+	return spi_write_dt(&cfg->bus, &tx);
+}
+
+static int dacx311_channel_setup(const struct device *dev,
+				const struct dac_channel_cfg *channel_cfg)
+{
+	struct dacx311_data *data = dev->data;
+
+	/* Validate configuration */
+	if (channel_cfg->channel_id > (DACX311_MAX_CHANNEL - 1)) {
+		LOG_ERR("Unsupported channel %d", channel_cfg->channel_id);
+		return -ENOTSUP;
+	}
+
+	if (channel_cfg->internal) {
+		LOG_ERR("Internal channels not supported");
+		return -ENOTSUP;
+	}
+
+	if (data->configured & BIT(channel_cfg->channel_id)) {
+		LOG_DBG("Channel %d already configured", channel_cfg->channel_id);
+		return 0;
+	}
+
+	/* Mark channel as configured */
+	data->configured |= BIT(channel_cfg->channel_id);
+
+	LOG_DBG("Channel %d initialized", channel_cfg->channel_id);
+
+	return 0;
+}
+
+static int dacx311_write_value(const struct device *dev, uint8_t channel,
+				uint32_t value)
+{
+	struct dacx311_data *data = dev->data;
+	uint16_t regval;
+	uint8_t shift;
+	int ret;
+
+	const bool brdcast = (channel == DAC_CHANNEL_BROADCAST) ? 1 : 0;
+
+	if (!brdcast && (channel > (DACX311_MAX_CHANNEL - 1))) {
+		LOG_ERR("Unsupported channel %d", channel);
+		return -ENOTSUP;
+	}
+
+	/*
+	 * Check if channel is initialized
+	 * If broadcast channel is used, check if any channel is initialized
+	 */
+	if ((brdcast && !data->configured) ||
+			(channel < DACX311_MAX_CHANNEL && !(data->configured & BIT(channel)))) {
+		LOG_ERR("Channel %d not initialized", channel);
+		return -EINVAL;
+	}
+
+	if (value >= (1 << (data->resolution))) {
+		LOG_ERR("Value %d out of range", value);
+		return -EINVAL;
+	}
+
+	/*
+	 * (See https://www.ti.com/document-viewer/dac6311/datasheet)
+	 *
+	 * Shift given value to align MSB bit position to register bit 13.
+	 *
+	 * DAC output register format:
+	 *
+	 * | 15 14 | 13 12 11 10  9  8  7  6  5  4  3  2  1  0         |
+	 * |-------|---------------------------------------------------|
+	 * | Mode  | 8311[13:0] / 7311[13:2] / 6311[13:4] / 5311[13:6] |
+	 */
+	shift = DACX311_MAX_RESOLUTION - data->resolution;
+	regval = value << shift;
+
+	/*
+	 * Set mode bits to value taken from configuration.
+	 *
+	 * MODE = 0 0  -> Normal Operation
+	 *        0 1  -> Output 1 kΩ to GND
+	 *        1 0  -> Output 100 kΩ to GND
+	 *        1 1  -> High-Z
+	 */
+	regval &= 0x3FFF;
+	regval |= data->power_down_mode;
+
+	/* Write to output */
+	ret = dacx311_reg_write(dev, regval);
+	if (ret) {
+		LOG_ERR("Unable to set value %d on channel %d", value, channel);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int dacx311_init(const struct device *dev)
+{
+	const struct dacx311_config *config = dev->config;
+	struct dacx311_data *data = dev->data;
+
+	/* Set bit resolution for this chip variant */
+	data->resolution = config->resolution;
+
+	/* Set the power mode (shifted to upper bits) */
+	data->power_down_mode = FIELD_PREP(BIT_MASK(2) << DACX311_MAX_RESOLUTION,
+			config->power_down_mode);
+
+	return 0;
+}
+
+static DEVICE_API(dac, dacx311_driver_api) = {
+	.channel_setup = dacx311_channel_setup,
+	.write_value = dacx311_write_value
+};
+
+#define INST_DT_DACX311(inst, t) DT_INST(inst, ti_dac##t)
+
+#define DACX311_DEVICE(t, n, res) \
+	BUILD_ASSERT(DT_INST_ENUM_IDX(n, power_down_mode) <= 3, \
+				"Invalid power down mode");\
+	BUILD_ASSERT(DT_PROP(INST_DT_DACX311(n, t), spi_max_frequency) \
+				<= DACX311_SPI_HZ_MAX, "Invalid SPI frequency");\
+	static struct dacx311_data dac##t##_data_##n; \
+	static const struct dacx311_config dac##t##_config_##n = { \
+		.bus = SPI_DT_SPEC_GET(INST_DT_DACX311(n, t), \
+					SPI_OP_MODE_MASTER | SPI_TRANSFER_MSB | \
+					SPI_MODE_CPHA | \
+					SPI_WORD_SET(16), 0),  \
+		.resolution = res, \
+		.power_down_mode = DT_INST_ENUM_IDX(n, power_down_mode), \
+	}; \
+	DEVICE_DT_DEFINE(INST_DT_DACX311(n, t), \
+			dacx311_init, NULL, \
+			&dac##t##_data_##n,			   \
+			&dac##t##_config_##n, POST_KERNEL,	   \
+			CONFIG_DAC_INIT_PRIORITY,		   \
+			&dacx311_driver_api)
+
+/*
+ * DAC8311: 14-bit
+ */
+#define DAC8311_DEVICE(n) DACX311_DEVICE(8311, n, DAC8311_RESOLUTION)
+/*
+ * DAC7311: 12-bit
+ */
+#define DAC7311_DEVICE(n) DACX311_DEVICE(7311, n, DAC7311_RESOLUTION)
+/*
+ * DAC6311: 10-bit
+ */
+#define DAC6311_DEVICE(n) DACX311_DEVICE(6311, n, DAC6311_RESOLUTION)
+/*
+ * DAC5311: 8-bit
+ */
+#define DAC5311_DEVICE(n) DACX311_DEVICE(5311, n, DAC5311_RESOLUTION)
+
+#define CALL_WITH_ARG(arg, expr) expr(arg)
+
+#define INST_DT_DACX311_FOREACH(t, inst_expr) \
+	LISTIFY(DT_NUM_INST_STATUS_OKAY(ti_dac##t), \
+		CALL_WITH_ARG, (), inst_expr)
+
+#define DT_DRV_COMPAT ti_dac8311
+INST_DT_DACX311_FOREACH(8311, DAC8311_DEVICE);
+#undef DT_DRV_COMPAT
+#define DT_DRV_COMPAT ti_dac7311
+INST_DT_DACX311_FOREACH(7311, DAC7311_DEVICE);
+#undef DT_DRV_COMPAT
+#define DT_DRV_COMPAT ti_dac6311
+INST_DT_DACX311_FOREACH(6311, DAC6311_DEVICE);
+#undef DT_DRV_COMPAT
+#define DT_DRV_COMPAT ti_dac5311
+INST_DT_DACX311_FOREACH(5311, DAC5311_DEVICE);
+#undef DT_DRV_COMPAT

dts/bindings/dac/ti,dac5311.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 Andreas Wolf <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+description: Texas Instrument 8-Bit DAC 5311
+
+compatible: "ti,dac5311"
+
+include: ti,dacx311-base.yaml

dts/bindings/dac/ti,dac6311.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 Andreas Wolf <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+description: Texas Instrument 10-Bit DAC 6311
+
+compatible: "ti,dac6311"
+
+include: ti,dacx311-base.yaml

dts/bindings/dac/ti,dac7311.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 Andreas Wolf <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+description: Texas Instrument 12-Bit DAC 7311
+
+compatible: "ti,dac7311"
+
+include: ti,dacx311-base.yaml

dts/bindings/dac/ti,dac8311.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 Andreas Wolf <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+description: Texas Instrument 14-Bit DAC 8311
+
+compatible: "ti,dac8311"
+
+include: ti,dacx311-base.yaml

dts/bindings/dac/ti,dacx311-base.yaml

@@ -0,0 +1,27 @@
+# Copyright (c) 2025 Andreas Wolf <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+include: [dac-controller.yaml, spi-device.yaml]
+
+properties:
+  "#io-channel-cells":
+    const: 1
+
+  power-down-mode:
+    type: string
+    default: "normal"
+    enum:
+      - "normal"
+      - "power-down-1k"
+      - "power-down-100k"
+      - "power-down-3-state"
+    description: |
+      Power-down mode select.
+      - Normal mode (reg: 0).
+      - 1 kOhm output impedance (reg: 1).
+      - 100 kOhm output impedance (reg: 2).
+      - Three-state output impedance (reg: 3).
+      The default corresponds to the reset value of the register field.
+
+io-channel-cells:
+  - output

tests/drivers/build_all/dac/app.overlay

@@ -125,6 +125,7 @@
 				   <&test_gpio 0 0>,
 				   <&test_gpio 0 0>,
 				   <&test_gpio 0 0>,
+				   <&test_gpio 0 0>,
 				   <&test_gpio 0 0>;
 
 			test_spi_dac60508: dac60508@0 {
@@ -331,6 +332,13 @@
 				spi-max-frequency = <0>;
 				#io-channel-cells = <1>;
 			};
+
+			test_spi_dac6311: dac6311@16 {
+				compatible = "ti,dac6311";
+				reg = <0x16>;
+				spi-max-frequency = <0>;
+				#io-channel-cells = <1>;
+			};
 		};
 	};
 };