drivers/analog: add mcp48xx dac support

Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>

include/nuttx/analog/dac.h

@@ -180,7 +180,7 @@ extern "C"
  *
  * Input Parameters:
  *    path - The full path to the DAC device to be registered.  This could
- *      be, as an example, "/dev/dac0"
+ *           be, as an example, "/dev/dac0"
  *    dev - An instance of the device-specific DAC interface
  *
  * Returned Value:
@@ -241,7 +241,25 @@ FAR struct dac_dev_s *dac7554_initialize(FAR struct spi_dev_s *spi,
  ****************************************************************************/
 
 FAR struct dac_dev_s *lmp92001_dac_initialize(FAR struct i2c_master_s *i2c,
-                                               uint8_t addr);
+                                              uint8_t addr);
+
+/****************************************************************************
+ * Name: mcp48xx_initialize
+ *
+ * Description:
+ *   Initialize DAC
+ *
+ * Input Parameters:
+ *    spi - SPI driver instance
+ *    spidev - SPI Chip Select number
+ *
+ * Returned Value:
+ *   Valid MCP48XX device structure reference on success; a NULL on failure
+ *
+ ****************************************************************************/
+
+FAR struct dac_dev_s *mcp48xx_initialize(FAR struct spi_dev_s *spi,
+                                         uint32_t spidev);
 
 #if defined(__cplusplus)
 }

include/nuttx/analog/ioctl.h

@@ -99,6 +99,11 @@
 #define AN_MAX1161X_FIRST (AN_STM32L4_FIRST + AN_STM32L4_NCMDS)
 #define AN_MAX1161X_NCMDS 8
 
+/* See include/nuttx/analog/mcp48xx.h */
+
+#define AN_MCP48XX_FIRST (AN_MAX1161X_FIRST + AN_MAX1161X_NCMDS)
+#define AN_MCP48XX_NCMDS 3
+
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/

include/nuttx/analog/mcp48xx.h

@@ -0,0 +1,73 @@
+/****************************************************************************
+ * include/nuttx/analog/mcp48xx.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.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_ANALOG_MCP48XX_H
+#define __INCLUDE_NUTTX_ANALOG_MCP48XX_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/analog/ioctl.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* IOCTL Commands ***********************************************************/
+
+/* Cmd: ANIOC_MCP48XX_DAC_SET_GAIN         Arg: mcp48xx_set_gain_e value
+ * Cmd: ANIOC_MCP48XX_DAC_ENABLE           Arg: mcp48xx_dac_channel_e channel
+ * Cmd: ANIOC_MCP48XX_DAC_DISABLE          Arg: mcp48xx_dac_channel_e channel
+ */
+
+#define ANIOC_MCP48XX_DAC_SET_GAIN         _ANIOC(AN_MCP48XX_FIRST + 0)
+#define ANIOC_MCP48XX_DAC_ENABLE           _ANIOC(AN_MCP48XX_FIRST + 1)
+#define ANIOC_MCP48XX_DAC_DISABLE          _ANIOC(AN_MCP48XX_FIRST + 2)
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+enum mcp48xx_gain_select_e
+{
+  MCP48XX_GAIN_2X  = 0 << 8U,  /* VOUT = 2 * VREF * D/4096 */
+  MCP48XX_GAIN_1X  = 1 << 8U   /* VOUT = VREF * D/4096 */
+};
+
+enum mcp48xx_dac_channel_e
+{
+  MCP48XX_DAC_CHA  = 1 << 0U,  /* Select channel A */
+  MCP48XX_DAC_CHB  = 1 << 1U,  /* Select channel B */
+  MCP48XX_DAC_ALL  = 0x3u      /* Select both channels A and B */
+};
+
+enum mcp48xx_set_gain_e
+{
+  MCP48XX_DAC_CHA_GAIN_2X = MCP48XX_DAC_CHA | MCP48XX_GAIN_2X,
+  MCP48XX_DAC_CHB_GAIN_2X = MCP48XX_DAC_CHB | MCP48XX_GAIN_2X,
+  MCP48XX_DAC_CHA_GAIN_1X = MCP48XX_DAC_CHA | MCP48XX_GAIN_1X,
+  MCP48XX_DAC_CHB_GAIN_1X = MCP48XX_DAC_CHB | MCP48XX_GAIN_1X,
+  MCP48XX_DAC_ALL_GAIN_2X = MCP48XX_DAC_ALL | MCP48XX_GAIN_2X,
+  MCP48XX_DAC_ALL_GAIN_1X = MCP48XX_DAC_ALL | MCP48XX_GAIN_1X
+};
+
+#endif /* __INCLUDE_NUTTX_ANALOG_MCP48XX_H */