drivers: dac: esp32: Add support for DAC controller

Initial DAC driver for the ESP32/ESP32-S2 SOCs

Signed-off-by: Marek Matej <marek.matej@espressif.com>

boards/xtensa/esp32/esp32.yaml

@@ -11,6 +11,7 @@ supported:
   - uart
   - nvs
   - pwm
+  - dac
 testing:
   ignore_tags:
     - net

drivers/dac/CMakeLists.txt

@@ -13,4 +13,5 @@ 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_MCP4728		dac_mcp4728.c)
 zephyr_library_sources_ifdef(CONFIG_DAC_GD32		dac_gd32.c)
+zephyr_library_sources_ifdef(CONFIG_DAC_ESP32		dac_esp32.c)
 zephyr_library_sources_ifdef(CONFIG_USERSPACE		dac_handlers.c)

drivers/dac/Kconfig

@@ -48,4 +48,6 @@ source "drivers/dac/Kconfig.mcp4728"
 
 source "drivers/dac/Kconfig.gd32"
 
+source "drivers/dac/Kconfig.esp32"
+
 endif # DAC

drivers/dac/Kconfig.esp32

@@ -0,0 +1,11 @@
+# ESP32 DAC configuration options
+
+# Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+config DAC_ESP32
+	bool "ESP32 DAC driver"
+	default y
+	depends on DT_HAS_ESPRESSIF_ESP32_DAC_ENABLED
+	help
+	  Enable the ESP32 DAC driver

drivers/dac/dac_esp32.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT espressif_esp32_dac
+
+#include <soc.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/dac.h>
+#include <zephyr/drivers/clock_control.h>
+#include <hal/rtc_io_types.h>
+#include <hal/rtc_io_hal.h>
+#include <hal/rtc_io_ll.h>
+#include <hal/dac_hal.h>
+#include <hal/dac_types.h>
+#include "driver/dac_common.h"
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(esp32_dac, CONFIG_DAC_LOG_LEVEL);
+
+struct dac_esp32_config {
+	int irq_source;
+	const struct device *clock_dev;
+	clock_control_subsys_t clock_subsys;
+};
+
+static int dac_esp32_write_value(const struct device *dev,
+				uint8_t channel, uint32_t value)
+{
+	ARG_UNUSED(dev);
+
+	dac_output_voltage(channel, value);
+
+	return 0;
+}
+
+static int dac_esp32_channel_setup(const struct device *dev,
+		   const struct dac_channel_cfg *channel_cfg)
+{
+	ARG_UNUSED(dev);
+
+	if (channel_cfg->channel_id > DAC_CHANNEL_MAX) {
+		LOG_ERR("Channel %d is not valid", channel_cfg->channel_id);
+		return -EINVAL;
+	}
+
+	dac_output_enable(channel_cfg->channel_id);
+
+	return 0;
+}
+
+static int dac_esp32_init(const struct device *dev)
+{
+	const struct dac_esp32_config *cfg = dev->config;
+
+	if (!cfg->clock_dev) {
+		LOG_ERR("Clock device missing");
+		return -EINVAL;
+	}
+
+	if (!device_is_ready(cfg->clock_dev)) {
+		LOG_ERR("Clock device not ready");
+		return -ENODEV;
+	}
+
+	if (clock_control_on(cfg->clock_dev,
+		(clock_control_subsys_t *) &cfg->clock_subsys) != 0) {
+		LOG_ERR("DAC clock setup failed (%d)", -EIO);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static const struct dac_driver_api dac_esp32_driver_api = {
+	.channel_setup = dac_esp32_channel_setup,
+	.write_value = dac_esp32_write_value
+};
+
+#define ESP32_DAC_INIT(id)									\
+												\
+	static const struct dac_esp32_config dac_esp32_config_##id = {				\
+		.irq_source = DT_INST_IRQN(id),							\
+		.clock_dev = DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(id)),				\
+		.clock_subsys =	(clock_control_subsys_t) DT_INST_CLOCKS_CELL(id, offset),	\
+	};											\
+												\
+	DEVICE_DT_INST_DEFINE(id,								\
+		&dac_esp32_init,								\
+		NULL,										\
+		NULL,										\
+		&dac_esp32_config_##id,								\
+		POST_KERNEL,									\
+		CONFIG_DAC_INIT_PRIORITY,							\
+		&dac_esp32_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(ESP32_DAC_INIT);

dts/bindings/dac/espressif,esp32-dac.yaml

@@ -0,0 +1,53 @@
+# Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+    Espressif Digital to Analog converter (DAC) control node
+    is part of the RTC low-power domain and belongs to the SENSE
+    peripherals set. RTC peripherals has GPIOs controlled by the
+    RTCIO mux, which is separated from the main IO mux.
+
+    Two GPIO pads can only be connected to the DAC peripheral.
+
+    ESP32 pads
+      - GPIO25 as DAC channel 1
+      - GPIO26 as DAC channel 2
+
+    ESP32-S2 pads
+      - GPIO17 as DAC channel 1
+      - GPIO18 as DAC channel 2
+
+    To enable the DAC peripheral it must be enabled in the board
+    dts, or in subsequent overlay file.
+
+          &dac {
+              status = "okay";
+          };
+
+    To specify the DAC channel to use, dts overlay must include
+    properties 'dac-channel-id', which uses zero based channel index.
+    Variable 'dac-resolution' must be also specified, although ESP32
+    only supported resolution is 8bits.
+
+          / {
+            zephyr,user {
+              dac = <&dac>;
+              dac-channel-id = <0>;
+              dac-resolution = <8>;
+            };
+          };
+
+    NOTE: The DAC peripheral outputs are fixed to gpio pads, therefore
+          it does not need to be controlled by the pinctrl node.
+
+compatible: "espressif,esp32-dac"
+
+include: [dac-controller.yaml]
+
+properties:
+
+    "#io-channel-cells":
+      const: 1
+
+io-channel-cells:
+    - output

dts/xtensa/espressif/esp32.dtsi

@@ -354,6 +354,16 @@
 			interrupt-parent = <&intc>;
 			status = "disabled";
 		};
+
+		dac: dac@3ff48800 {
+			compatible = "espressif,esp32-dac";
+			reg = <0x3ff48800 0x100>;
+			interrupts = <RTC_CORE_INTR_SOURCE>;
+			interrupt-parent = <&intc>;
+			clocks = <&rtc ESP32_SARADC_MODULE>;
+			#io-channel-cells = <1>;
+			status = "disabled";
+		};
 	};
 
 };

dts/xtensa/espressif/esp32s2.dtsi

@@ -254,6 +254,16 @@
 			clocks = <&rtc ESP32_TIMG1_MODULE>;
 			status = "disabled";
 		};
+
+		dac: dac@3f408800 {
+			compatible = "espressif,esp32-dac";
+			reg = <0x3f408800 0x100>;
+			interrupts = <RTC_CORE_INTR_SOURCE>;
+			interrupt-parent = <&intc>;
+			clocks = <&rtc ESP32_PERIPH_SARADC_MODULE>;
+			#io-channel-cells = <1>;
+			status = "disabled";
+		};
 	};
 
 };

include/zephyr/dt-bindings/pinctrl/esp32-gpio-sigmap.h

@@ -419,4 +419,26 @@
 #define ESP_SIG_IN_FUNC228		228
 #define ESP_SIG_GPIO_OUT		256
 
+/* RTC-IO MUX */
+#define ESP_ADC1_CH0		0
+#define ESP_ADC1_CH1		1
+#define ESP_ADC1_CH2		2
+#define ESP_ADC1_CH3		3
+#define ESP_ADC1_CH6		4
+#define ESP_ADC1_CH7		5
+#define ESP_ADC2_CH8		6
+#define ESP_ADC2_CH9		7
+#define ESP_DAC1_OUT		6
+#define ESP_DAC2_OUT		7
+#define ESP_ADC1_CH5		8
+#define ESP_ADC1_CH4		9
+#define ESP_ADC2_CH0		10
+#define ESP_ADC2_CH1		11
+#define ESP_ADC2_CH2		12
+#define ESP_ADC2_CH3		13
+#define ESP_ADC2_CH4		14
+#define ESP_ADC2_CH5		15
+#define ESP_ADC2_CH6		16
+#define ESP_ADC2_CH7		17
+
 #endif /* ZEPHYR_INCLUDE_DT_BINDINGS_PINCTRL_ESP32_GPIO_SIGMAP_H_ */