drivers/sensors: Add AS5047D magnetic encoder driver

This adds support for the AMS AS5047D SPI magnetic encoder.

Features:
- 14-bit angle read
- SPI interface
- basic error handling

Tested on STM32F4 with SPI3.

Signed-off-by: Dheeraj Singh <Dheerajsingh1107@gmail.com>

Author: Dheeraj Singh

Documentation/components/drivers/character/quadrature.rst

@@ -78,6 +78,36 @@ This ioctl sets the index position of the encoder. An argument is an
 This ioctl gets the index position of the encoder. An argument is a
 pointer to ``qe_index_s`` structure.
 
+AS5047D Specific Interface
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The AS5047D magnetic rotary encoder is supported through the quadrature
+encoder upper-half driver by ``drivers/sensors/as5047d.c``.
+
+Include the AS5047D header for device-specific ioctls and bit definitions:
+
+.. code-block:: c
+
+  #include <nuttx/sensors/as5047d.h>
+
+The AS5047D implements additional ``ioctl`` commands:
+
+ * :c:macro:`QEIOC_AS5047D_DIAGNOSTICS`
+ * :c:macro:`QEIOC_AS5047D_MAGNITUDE`
+
+.. c:macro:: QEIOC_AS5047D_DIAGNOSTICS
+
+Reads the AS5047D ``DIAAGC`` register. The argument is a pointer to
+``uint16_t`` where the register value is returned.
+
+.. c:macro:: QEIOC_AS5047D_MAGNITUDE
+
+Reads the AS5047D ``MAG`` register. The argument is a pointer to
+``uint16_t`` where the register value is returned.
+
+The position value returned by :c:macro:`QEIOC_POSITION` is a 14-bit
+angle sample in the range ``0`` to ``16383``.
+
 .. c:struct:: qe_index_s
 .. code-block:: c
 
@@ -124,3 +154,8 @@ reader should refer to target documentation for target specific configuration.
 The ``CONFIG_SENSORS`` option has to be enabled in order to use the qencoder
 peripheral. The peripheral itself is enabled by ``CONFIG_SENSORS_QENCODER``
 option.
+
+For AS5047D, enable these options:
+
+- ``CONFIG_SPI``
+- ``CONFIG_SENSORS_AS5047D``

Documentation/platforms/arm/stm32f4/boards/nucleo-f446re/index.rst

@@ -408,6 +408,36 @@ testing purposes::
     PB_6 - GPIO_OUTPUT
     PC_7 - GPIO_INPUT_INTERRUPT
 
+as5047d
+-------
+
+This is basically an ``nsh`` configuration (see above) with added support
+for the AMS AS5047D magnetic rotary encoder using the quadrature encoder
+framework.
+
+Board bring-up initializes AS5047D on SPI3 and registers it as
+``/dev/qe0``.
+
+AS5047D connection (SPI3)::
+
+    AS5047D Signal   Nucleo-F446RE Pin
+    --------------   -----------------
+    SCK              PC10
+    MISO             PC11
+    MOSI             PC12
+    CS               PA15 (D8, GPIO_SPI3_CS_USER)
+
+Relevant configuration options::
+
+    CONFIG_SPI=y
+    CONFIG_STM32_SPI3=y
+    CONFIG_SENSORS=y
+    CONFIG_SENSORS_QENCODER=y
+    CONFIG_SENSORS_AS5047D=y
+
+You can verify encoder operation from NuttShell with the qencoder example
+application (``qe``), which reads position data from ``/dev/qe0``.
+
 ihm08m1_f32 and ihm08m1_b16
 ---------------------------
 

boards/arm/stm32/nucleo-f446re/configs/qenco/defconfig

@@ -19,8 +19,7 @@ CONFIG_BOARD_LOOPSPERMSEC=8499
 CONFIG_BUILTIN=y
 CONFIG_DEBUG_SYMBOLS=y
 CONFIG_EXAMPLES_QENCODER=y
-CONFIG_EXAMPLES_QENCODER_HAVE_MAXPOS=y
-CONFIG_EXAMPLES_QENCODER_MAXPOS=8192
+CONFIG_EXAMPLES_QENCODER_NSAMPLES=10
 CONFIG_INIT_ENTRYPOINT="nsh_main"
 CONFIG_INTELHEX_BINARY=y
 CONFIG_MQ_MAXMSGSIZE=5
@@ -35,13 +34,14 @@ CONFIG_RAW_BINARY=y
 CONFIG_RR_INTERVAL=200
 CONFIG_SCHED_WAITPID=y
 CONFIG_SENSORS=y
-CONFIG_SENSORS_QENCODER=y
+CONFIG_SENSORS_AS5047D=y
 CONFIG_START_DAY=14
 CONFIG_START_MONTH=10
 CONFIG_START_YEAR=2014
 CONFIG_STM32_JTAG_SW_ENABLE=y
 CONFIG_STM32_QENCODER_DISABLE_EXTEND16BTIMERS=y
 CONFIG_STM32_QENCODER_SAMPLE_FDTS_2=y
+CONFIG_STM32_SPI3=y
 CONFIG_STM32_TIM2=y
 CONFIG_STM32_TIM2_QE=y
 CONFIG_STM32_TIM2_QEPSC=0

boards/arm/stm32/nucleo-f446re/include/board.h

@@ -304,9 +304,35 @@
 #define GPIO_SPI2_MOSI   GPIO_SPI2_MOSI_1
 #define GPIO_SPI2_SCK    GPIO_SPI2_SCK_2
 
-#define GPIO_SPI3_MISO   GPIO_SPI3_MISO_1
-#define GPIO_SPI3_MOSI   GPIO_SPI3_MOSI_1
-#define GPIO_SPI3_SCK    GPIO_SPI3_SCK_1
+/* SPI3 has two alternate pin mappings on this board:
+ *
+ * - LCD path uses PB3/PB4/PB5
+ * - AS5047D path uses PC10/PC11/PC12
+ *
+ * Select pinmux by feature so both use-cases are supported in-tree.
+ */
+
+#if defined(CONFIG_LCD_ILI9225) && defined(CONFIG_SENSORS_AS5047D)
+#  error "LCD (ILI9225) and AS5047D require different SPI3 pin mappings"
+#elif defined(CONFIG_SENSORS_AS5047D)
+#  define GPIO_SPI3_MISO   GPIO_SPI3_MISO_2
+#  define GPIO_SPI3_MOSI   GPIO_SPI3_MOSI_2
+#  define GPIO_SPI3_SCK    GPIO_SPI3_SCK_2
+#else
+#  define GPIO_SPI3_MISO   GPIO_SPI3_MISO_1
+#  define GPIO_SPI3_MOSI   GPIO_SPI3_MOSI_1
+#  define GPIO_SPI3_SCK    GPIO_SPI3_SCK_1
+#endif
+
+/* Encoder SPI CS from your reference:
+ *   #define ENC_CS GPIOA, GPIO_PIN_15
+ */
+
+#define ENC_CS_PORT      GPIO_PORTA
+#define ENC_CS_PIN       GPIO_PIN15
+#define GPIO_SPI3_CS_USER \
+  (GPIO_OUTPUT | GPIO_PUSHPULL | GPIO_SPEED_50MHz | GPIO_OUTPUT_SET \
+   | ENC_CS_PORT | ENC_CS_PIN)
 
 /* CAN */
 

boards/arm/stm32/nucleo-f446re/src/stm32_bringup.c

@@ -60,6 +60,10 @@
 #  include <nuttx/leds/userled.h>
 #endif
 
+#ifdef CONFIG_SENSORS_AS5047D
+#include <nuttx/sensors/as5047d.h>
+#endif
+
 #include "stm32_romfs.h"
 #include "nucleo-f446re.h"
 
@@ -84,6 +88,10 @@
 int stm32_bringup(void)
 {
   int ret = OK;
+#if defined(CONFIG_SENSORS_QENCODER) && defined(CONFIG_SENSORS_AS5047D)
+  FAR struct spi_dev_s *spi;
+  FAR struct qe_lowerhalf_s *lower;
+#endif
 
 #ifdef CONFIG_FS_PROCFS
   /* Mount the procfs file system */
@@ -197,16 +205,45 @@ int stm32_bringup(void)
 #endif
 
 #ifdef CONFIG_SENSORS_QENCODER
-  /* Initialize and register the qencoder driver */
+#ifdef CONFIG_SENSORS_AS5047D
+  /* Initialize and register the AS5047D qencoder driver */
+
+  spi = stm32_spibus_initialize(3);
+  if (spi == NULL)
+    {
+      syslog(LOG_ERR, "ERROR: Failed to initialize SPI3 for AS5047D\n");
+      return -ENODEV;
+    }
+
+#ifdef GPIO_SPI3_CS_USER
+  stm32_configgpio(GPIO_SPI3_CS_USER);
+#endif
+
+  lower = as5047d_initialize(spi, SPIDEV_USER(0));
+  if (lower == NULL)
+    {
+      syslog(LOG_ERR, "ERROR: as5047d_initialize() failed\n");
+      return -ENODEV;
+    }
+
+  ret = qe_register("/dev/qe0", lower);
+  if (ret < 0)
+    {
+      syslog(LOG_ERR, "ERROR: qe_register(/dev/qe0) failed: %d\n", ret);
+      return ret;
+    }
+#else
+  /* Initialize and register the STM32 timer qencoder driver */
 
   ret = board_qencoder_initialize(0, CONFIG_NUCLEO_F446RE_QETIMER);
   if (ret != OK)
     {
       syslog(LOG_ERR,
-             "ERROR: Failed to register the qencoder: %d\n",
+             "ERROR: Failed to register timer qencoder: %d\n",
              ret);
       return ret;
     }
+#  endif
 #endif
 
 #ifdef CONFIG_SENSORS_HALL3PHASE

boards/arm/stm32/nucleo-f446re/src/stm32_spi.c

@@ -175,6 +175,10 @@ void stm32_spi3select(struct spi_dev_s *dev, uint32_t devid,
   spiinfo("devid: %d CS: %s\n",
           (int)devid, selected ? "assert" : "de-assert");
 
+#ifdef GPIO_SPI3_CS_USER
+      stm32_gpiowrite(GPIO_SPI3_CS_USER, !selected);
+#endif
+
 #ifdef HAVE_LCD
       stm32_gpiowrite(GPIO_LCD_CS, !selected);
 #endif

drivers/sensors/CMakeLists.txt

@@ -412,6 +412,10 @@ if(CONFIG_SENSORS)
       list(APPEND SRCS adt7320.c)
     endif()
 
+    if(CONFIG_SENSORS_AS5047D)
+      list(APPEND SRCS as5047d.c)
+    endif()
+    
     if(CONFIG_SENSORS_AS5048A)
       list(APPEND SRCS as5048a.c)
     endif()

drivers/sensors/Kconfig

@@ -159,6 +159,14 @@ config SENSORS_AS5048A
 	---help---
 		Enable driver support for the AMS AS5048A magnetic rotary encoder.
 
+config SENSORS_AS5047D
+	bool "AMS AS5047D Magnetic Rotary Encoder support"
+	default n
+	select SPI
+	select SENSORS_QENCODER
+	---help---
+		Enable driver support for the AMS AS5047D magnetic rotary encoder.
+
 config SENSORS_AS726X
 	bool "AMS AS726X Spetral sensor support"
 	default n

drivers/sensors/Make.defs

@@ -408,6 +408,10 @@ ifeq ($(CONFIG_SENSORS_AS5048A),y)
   CSRCS += as5048a.c
 endif
 
+ifeq ($(CONFIG_SENSORS_AS5047D),y)
+  CSRCS += as5047d.c
+endif
+
 endif # CONFIG_SPI
 
 # These drivers depend on 1WIRE support