drivers: dac: introduce gd32 dac driver

Add DAC driver for gd32 series SoCs.

Signed-off-by: HaiLong Yang <cameledyang@pm.me>

drivers/dac/CMakeLists.txt

@@ -11,4 +11,5 @@ 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_DAC_GD32		dac_gd32.c)
 zephyr_library_sources_ifdef(CONFIG_USERSPACE		dac_handlers.c)

drivers/dac/Kconfig

@@ -44,4 +44,6 @@ source "drivers/dac/Kconfig.dacx3608"
 
 source "drivers/dac/Kconfig.mcp4725"
 
+source "drivers/dac/Kconfig.gd32"
+
 endif # DAC

drivers/dac/Kconfig.gd32

@@ -0,0 +1,15 @@
+# DAC configuration options
+
+# Copyright (c) 2021 BrainCo Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+# Workaround for not being able to have commas in macro arguments
+DT_COMPAT_GD_GD32_DAC := gd,gd32-dac
+
+config DAC_GD32
+	bool "GD32 DAC driver"
+	depends on SOC_FAMILY_GD32
+	default $(dt_compat_enabled,$(DT_COMPAT_GD_GD32_DAC))
+	help
+	  Enable GigaDevice GD32 DAC driver

drivers/dac/dac_gd32.c

@@ -0,0 +1,167 @@
+/*
+ * Copyright (c) 2021 BrainCo Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT gd_gd32_dac
+
+#include <errno.h>
+#include <drivers/pinctrl.h>
+#include <drivers/dac.h>
+#include <soc.h>
+
+#include <logging/log.h>
+LOG_MODULE_REGISTER(dac_gd32, CONFIG_DAC_LOG_LEVEL);
+
+/**
+ * GD32 DAC HAL use different DAC0 interface for 2 or 1 output channels SoCs.
+ * Unify the DAC0 interface to DAC0_xx.
+ */
+#if DT_INST_PROP(0, num_channels) == 1
+#define DAC_CTL_DEN0 DAC_CTL_DEN
+#define DAC0_R8DH    DAC_R8DH
+#define DAC0_R12DH   DAC_R12DH
+#endif
+
+struct dac_gd32_config {
+	uint32_t reg;
+	uint32_t rcu_periph_clock;
+	const struct pinctrl_dev_config *pcfg;
+	uint32_t num_channels;
+	uint32_t reset_val;
+};
+
+struct dac_gd32_data {
+	uint8_t resolutions[2];
+};
+
+static void dac_gd32_enable(uint8_t dacx)
+{
+	switch (dacx) {
+	case 0U:
+		DAC_CTL |= DAC_CTL_DEN0;
+		break;
+#if DT_INST_PROP(0, num_channels) == 2
+	case 1U:
+		DAC_CTL |= DAC_CTL_DEN1;
+		break;
+#endif
+	}
+}
+
+static void dac_gd32_disable(uint8_t dacx)
+{
+	switch (dacx) {
+	case 0U:
+		DAC_CTL &= ~DAC_CTL_DEN0;
+		break;
+#if DT_INST_PROP(0, num_channels) == 2
+	case 1U:
+		DAC_CTL &= ~DAC_CTL_DEN1;
+		break;
+#endif
+	}
+}
+
+static void dac_gd32_write(struct dac_gd32_data *data,
+			   uint8_t dacx, uint32_t value)
+{
+	switch (dacx) {
+	case 0U:
+		if (data->resolutions[dacx] == 8U) {
+			DAC0_R8DH = value;
+		} else {
+			DAC0_R12DH = value;
+		}
+		break;
+#if DT_INST_PROP(0, num_channels) == 2
+	case 1U:
+		if (data->resolutions[dacx] == 8U) {
+			DAC1_R8DH = value;
+		} else {
+			DAC1_R12DH = value;
+		}
+		break;
+#endif
+	}
+}
+
+static int dac_gd32_channel_setup(const struct device *dev,
+				  const struct dac_channel_cfg *channel_cfg)
+{
+	struct dac_gd32_data *data = dev->data;
+	const struct dac_gd32_config *config = dev->config;
+	uint8_t dacx = channel_cfg->channel_id;
+
+	if (dacx >= config->num_channels) {
+		return -ENOTSUP;
+	}
+
+	/* GD32 DAC only support 8 or 12 bits resolution */
+	if ((channel_cfg->resolution != 8U) &&
+	    (channel_cfg->resolution != 12U)) {
+		LOG_ERR("Only 8 and 12 bits resolutions are supported!");
+		return -ENOTSUP;
+	}
+
+	data->resolutions[dacx] = channel_cfg->resolution;
+
+	dac_gd32_disable(dacx);
+	dac_gd32_write(data, dacx, config->reset_val);
+	dac_gd32_enable(dacx);
+
+	return 0;
+}
+
+static int dac_gd32_write_value(const struct device *dev,
+				uint8_t dacx, uint32_t value)
+{
+	struct dac_gd32_data *data = dev->data;
+	const struct dac_gd32_config *config = dev->config;
+
+	if (dacx >= config->num_channels) {
+		return -ENOTSUP;
+	}
+
+	dac_gd32_write(data, dacx, value);
+
+	return 0;
+}
+
+struct dac_driver_api dac_gd32_driver_api = {
+	.channel_setup = dac_gd32_channel_setup,
+	.write_value = dac_gd32_write_value
+};
+
+static int dac_gd32_init(const struct device *dev)
+{
+	const struct dac_gd32_config *cfg = dev->config;
+	int ret;
+
+	ret = pinctrl_apply_state(cfg->pcfg, PINCTRL_STATE_DEFAULT);
+	if (ret < 0) {
+		LOG_ERR("Failed to apply pinctrl state");
+		return ret;
+	}
+
+	rcu_periph_clock_enable(cfg->rcu_periph_clock);
+
+	return 0;
+}
+
+PINCTRL_DT_INST_DEFINE(0)
+
+static struct dac_gd32_data dac_gd32_data_0;
+
+static const struct dac_gd32_config dac_gd32_cfg_0 = {
+	.reg = DT_INST_REG_ADDR(0),
+	.rcu_periph_clock = DT_INST_PROP(0, rcu_periph_clock),
+	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(0),
+	.num_channels = DT_INST_PROP(0, num_channels),
+	.reset_val = DT_INST_PROP(0, reset_val),
+};
+
+DEVICE_DT_INST_DEFINE(0, &dac_gd32_init, NULL, &dac_gd32_data_0,
+		      &dac_gd32_cfg_0, POST_KERNEL, CONFIG_DAC_INIT_PRIORITY,
+		      &dac_gd32_driver_api);