esp32: Add MAX6675 temperature sensor support

boards/xtensa/esp32/common/include/esp32_max6675.h

@@ -0,0 +1,36 @@
+/****************************************************************************
+ * boards/xtensa/esp32/common/include/esp32_max6675.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: board_max6675_initialize
+ *
+ * Description:
+ *   Initialize and register the MAX6675 Temperature Sensor driver.
+ *
+ * Input Parameters:
+ *   devno - The device number, used to build the device path as /dev/tempN
+ *   busno - The SPI bus number
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int board_max6675_initialize(int devno, int busno);

boards/xtensa/esp32/common/src/Make.defs

@@ -40,6 +40,10 @@ ifeq ($(CONFIG_ESP32_PCNT_AS_QE),y)
   CSRCS += esp32_qencoder.c
 endif
 
+ifeq ($(CONFIG_SENSORS_MAX6675),y)
+  CSRCS += esp32_max6675.c
+endif
+
 ifeq ($(CONFIG_AUDIO_CS4344),y)
   CSRCS += esp32_cs4344.c
 endif

boards/xtensa/esp32/common/src/esp32_max6675.c

@@ -0,0 +1,103 @@
+/****************************************************************************
+ * boards/xtensa/esp32/common/src/esp32_max6675.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/arch.h>
+#include <nuttx/sensors/max6675.h>
+#include <nuttx/spi/spi.h>
+#include <stdio.h>
+#include <debug.h>
+#include "esp32_spi.h"
+
+#ifdef CONFIG_SENSORS_MAX6675
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: board_max6675_initialize
+ *
+ * Description:
+ *   Initialize and register the MAX6675 Temperature Sensor driver.
+ *
+ * Input Parameters:
+ *   devno - The device number, used to build the device path as /dev/tempN
+ *   busno - The SPI bus number
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int board_max6675_initialize(int devno, int busno)
+{
+  struct spi_dev_s *spi;
+  char devpath[12];
+  int ret;
+
+  spi = esp32_spibus_initialize(busno);
+
+  if (!spi)
+    {
+      return -ENODEV;
+    }
+
+  /* Then register the barometer sensor */
+
+  snprintf(devpath, sizeof(devpath), "/dev/temp%d", devno);
+  ret = max6675_register(devpath, spi);
+  if (ret < 0)
+    {
+      snerr("ERROR: Error registering MAX6675\n");
+    }
+
+  return ret;
+}
+
+#endif

boards/xtensa/esp32/esp32-devkitc/configs/max6675/defconfig

@@ -0,0 +1,50 @@
+#
+# This file is autogenerated: PLEASE DO NOT EDIT IT.
+#
+# You can use "make menuconfig" to make any modifications to the installed .config file.
+# You can then do "make savedefconfig" to generate a new defconfig file that includes your
+# modifications.
+#
+# CONFIG_ARCH_LEDS is not set
+# CONFIG_NSH_ARGCAT is not set
+# CONFIG_NSH_CMDOPT_HEXDUMP is not set
+# CONFIG_NSH_CMDPARMS is not set
+CONFIG_ARCH="xtensa"
+CONFIG_ARCH_BOARD="esp32-devkitc"
+CONFIG_ARCH_BOARD_COMMON=y
+CONFIG_ARCH_BOARD_ESP32_DEVKITC=y
+CONFIG_ARCH_CHIP="esp32"
+CONFIG_ARCH_CHIP_ESP32=y
+CONFIG_ARCH_CHIP_ESP32WROVER=y
+CONFIG_ARCH_STACKDUMP=y
+CONFIG_ARCH_XTENSA=y
+CONFIG_BOARD_LOOPSPERMSEC=16717
+CONFIG_BUILTIN=y
+CONFIG_ESP32_SPI2=y
+CONFIG_ESP32_UART0=y
+CONFIG_EXAMPLES_MAX31855=y
+CONFIG_EXAMPLES_MAX31855_PROGNAME="max6675"
+CONFIG_FS_PROCFS=y
+CONFIG_HAVE_CXX=y
+CONFIG_HAVE_CXXINITIALIZE=y
+CONFIG_IDLETHREAD_STACKSIZE=3072
+CONFIG_INIT_ENTRYPOINT="nsh_main"
+CONFIG_INTELHEX_BINARY=y
+CONFIG_MM_REGIONS=3
+CONFIG_NSH_ARCHINIT=y
+CONFIG_NSH_BUILTIN_APPS=y
+CONFIG_NSH_FILEIOSIZE=512
+CONFIG_NSH_LINELEN=64
+CONFIG_NSH_READLINE=y
+CONFIG_PREALLOC_TIMERS=4
+CONFIG_RAM_SIZE=114688
+CONFIG_RAM_START=0x20000000
+CONFIG_RR_INTERVAL=200
+CONFIG_SCHED_WAITPID=y
+CONFIG_SENSORS=y
+CONFIG_SENSORS_MAX6675=y
+CONFIG_START_DAY=6
+CONFIG_START_MONTH=12
+CONFIG_START_YEAR=2011
+CONFIG_SYSTEM_NSH=y
+CONFIG_UART0_SERIAL_CONSOLE=y

boards/xtensa/esp32/esp32-devkitc/src/esp32_bringup.c

@@ -143,6 +143,10 @@
 #  include "esp32_lcd_backpack.h"
 #endif
 
+#ifdef CONFIG_SENSORS_MAX6675
+#  include "esp32_max6675.h"
+#endif
+
 #include "esp32-devkitc.h"
 
 /****************************************************************************
@@ -257,6 +261,14 @@ int esp32_bringup(void)
     }
 #endif /* CONFIG_ESP32_LEDC */
 
+#ifdef CONFIG_SENSORS_MAX6675
+  ret = board_max6675_initialize(0, 2);
+  if (ret < 0)
+    {
+      syslog(LOG_ERR, "ERROR: MAX6675 initialization failed: %d\n", ret);
+    }
+#endif
+
 #ifdef CONFIG_ESP32_TWAI
 
   /* Initialize TWAI and register the TWAI driver. */