drivers: dac: Add driver for NXP GAU DAC

Add driver for NXP GAU DAC using MCUX HAL.

Signed-off-by: Declan Snyder <declan.snyder@nxp.com>

drivers/dac/CMakeLists.txt

@@ -23,3 +23,4 @@ zephyr_library_sources_ifdef(CONFIG_DAC_AD559X		dac_ad559x.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_AD56XX		dac_ad56xx.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_AD569X		dac_ad569x.c)
 zephyr_library_sources_ifdef(CONFIG_USERSPACE		dac_handlers.c)
+zephyr_library_sources_ifdef(CONFIG_DAC_MCUX_GAU	dac_mcux_gau.c)

drivers/dac/Kconfig.mcux

@@ -31,3 +31,10 @@ config DAC_MCUX_DAC32_TESTOUT
 	depends on DAC_MCUX_DAC32
 	help
 	  Enable the DAC test output.
+
+config DAC_MCUX_GAU
+	bool "NXP GAU DAC driver"
+	default y
+	depends on DT_HAS_NXP_GAU_DAC_ENABLED
+	help
+	  Enable the driver for the NXP GAU DAC.

drivers/dac/dac_mcux_gau.c

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2023 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT nxp_gau_dac
+
+#include <zephyr/drivers/dac.h>
+
+#include <fsl_dac.h>
+
+#define LOG_LEVEL CONFIG_DAC_LOG_LEVEL
+#include <zephyr/logging/log.h>
+#include <zephyr/irq.h>
+LOG_MODULE_REGISTER(nxp_gau_dac);
+
+struct nxp_gau_dac_config {
+	DAC_Type *base;
+	dac_conversion_rate_t conversion_rate : 2;
+	dac_reference_voltage_source_t voltage_ref : 1;
+	dac_output_voltage_range_t output_range : 2;
+};
+
+static inline dac_channel_id_t convert_channel_id(uint8_t channel_id)
+{
+	switch (channel_id) {
+	case 0: return kDAC_ChannelA;
+	case 1: return kDAC_ChannelB;
+	default:
+		LOG_ERR("Invalid DAC channel ID");
+		return -EINVAL;
+	};
+}
+
+static int nxp_gau_dac_channel_setup(const struct device *dev,
+			const struct dac_channel_cfg *channel_cfg)
+{
+	const struct nxp_gau_dac_config *config = dev->config;
+	dac_channel_config_t dac_channel_config = {0};
+
+	if (channel_cfg->resolution != 10) {
+		LOG_ERR("DAC only support 10 bit resolution");
+		return -EINVAL;
+	}
+
+	if (channel_cfg->buffered) {
+		/* External and internal output are mutually exclusive */
+		LOG_WRN("Note: buffering DAC output to pad disconnects internal output");
+	}
+
+	dac_channel_config.waveType = kDAC_WaveNormal;
+	dac_channel_config.outMode = channel_cfg->buffered ?
+				kDAC_ChannelOutputPAD : kDAC_ChannelOutputInternal;
+	dac_channel_config.timingMode = kDAC_NonTimingCorrelated;
+	dac_channel_config.enableTrigger = false;
+	dac_channel_config.enableDMA = false;
+	dac_channel_config.enableConversion = true;
+
+	DAC_SetChannelConfig(config->base,
+			(uint32_t)convert_channel_id(channel_cfg->channel_id),
+			&dac_channel_config);
+
+	return 0;
+};
+
+static int nxp_gau_dac_write_value(const struct device *dev,
+				uint8_t channel, uint32_t value)
+{
+	const struct nxp_gau_dac_config *config = dev->config;
+
+	DAC_SetChannelData(config->base,
+			(uint32_t)convert_channel_id(channel),
+			(uint16_t)value);
+	return 0;
+};
+
+static const struct dac_driver_api nxp_gau_dac_driver_api = {
+	.channel_setup = nxp_gau_dac_channel_setup,
+	.write_value = nxp_gau_dac_write_value,
+};
+
+static int nxp_gau_dac_init(const struct device *dev)
+{
+	const struct nxp_gau_dac_config *config = dev->config;
+	dac_config_t dac_cfg;
+
+	DAC_GetDefaultConfig(&dac_cfg);
+
+	dac_cfg.conversionRate = config->conversion_rate;
+	dac_cfg.refSource = config->voltage_ref;
+	dac_cfg.rangeSelect = config->output_range;
+
+	DAC_Init(config->base, &dac_cfg);
+
+	return 0;
+};
+
+#define NXP_GAU_DAC_INIT(inst)							\
+										\
+	const struct nxp_gau_dac_config nxp_gau_dac_##inst##_config = {		\
+		.base = (DAC_Type *) DT_INST_REG_ADDR(inst),			\
+		.voltage_ref = DT_INST_ENUM_IDX(inst, nxp_dac_reference),	\
+		.conversion_rate = DT_INST_ENUM_IDX(inst, nxp_conversion_rate),	\
+		.output_range = DT_INST_ENUM_IDX(inst,				\
+						nxp_output_voltage_range),	\
+	};									\
+										\
+										\
+	DEVICE_DT_INST_DEFINE(inst, &nxp_gau_dac_init, NULL,			\
+				NULL,						\
+				&nxp_gau_dac_##inst##_config,			\
+				POST_KERNEL, CONFIG_DAC_INIT_PRIORITY,		\
+				&nxp_gau_dac_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(NXP_GAU_DAC_INIT)