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configs/tm4c123g-launchpad/src/tm4c_adc.c

+/************************************************************************************
+ * configs/tn4c123g-launchpad/tm4c_adc.c
+ *
+ *   Copyright (C) 2015 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************************/
+
+/************************************************************************************
+ * Included Files
+ ************************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/analog/adc.h>
+
+#include "tiva_adc.h"
+#include "tiva_timer.h"
+#include "tm4c123g-launchpad.h"
+
+/************************************************************************************
+ * Pre-processor Definitions
+ ************************************************************************************/
+
+#define TIVA_KILO    1000
+#define TIVA_TIME_US (SYSCLK_FREQUENCY/KILO)
+#define TIVA_TIME_MS (TIME_US*KILO)
+
+#define TIVA_TIME_US_TO_TICKS(x) (x*TIME_US)
+#define TIVA_TIME_MS_TO_TICKS(x) (x*TIME_MS)
+
+/************************************************************************************
+ * Private Data
+ ************************************************************************************/
+
+/************************************************************************************
+ * Private Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Public Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Name: board_adc_initialize
+ *
+ * Description:
+ *   Initialize and register the ADC driver
+ *
+ ************************************************************************************/
+
+#ifdef CONFIG_TIVA_ADC
+int board_adc_initialize(void)
+{
+  static bool initialized = false;
+  struct adc_dev_s *adc;
+  int ret;
+
+  /* Check if we have already initialized */
+
+  if (!initialized)
+    {
+      /* Call tiva_adcinitialize() to get an instance of the ADC interface */
+
+      adc = tiva_adc_initialize(0);
+      if (adc == NULL)
+        {
+          adbg("ERROR: Failed to get ADC interface\n");
+          return -ENODEV;
+        }
+
+      /* Register the ADC driver at "/dev/adc0" */
+
+      ret = adc_register("/dev/adc0", adc);
+      if (ret < 0)
+        {
+          adbg("adc_register failed: %d\n", ret);
+          return ret;
+        }
+
+      /* Now we are initialized */
+
+      initialized = true;
+    }
+
+  return OK;
+}
+#endif /* CONFIG_ADC */
+
+/************************************************************************************
+ * Name: adc_devinit
+ *
+ * Description:
+ *   All Tiva architectures must provide the following interface to work with
+ *   examples/adc.
+ *
+ ************************************************************************************/
+
+#ifdef CONFIG_EXAMPLES_ADC
+int adc_devinit(void)
+{
+#ifdef CONFIG_TIVA_ADC
+  return board_adc_initialize();
+#else
+  return -ENOSYS;
+#endif
+}
+#endif /* CONFIG_EXAMPLES_ADC */
+
+#if defined (CONFIG_TIVA_ADC) && defined (CONFIG_TIVA_TIMER)
+#  if 0
+/************************************************************************************
+ * Name: adc_timer_init
+ *
+ * Description:
+ *   Inititalize timer specifically for ADC use.
+ *
+ ************************************************************************************/
+
+TIMER_HANDLE adc_timer_init(void)
+{
+  struct tiva_gptm32config_s adctimer =
+  {
+    .cmn =
+    {
+      .gptm = 0;
+      .mode = TIMER32_MODE_PERIODIC;
+      .alternate = false;
+    };
+    .config =
+    {
+      .flags = TIMER_FLAG_ADCTIMEOUT;
+      .handler = NULL;
+      .u.periodic = TIVA_TIME_MS_TO_TICKS(100); // in clock ticks
+    };
+  };
+
+  return tiva_gptm_configure((const struct tiva_gptmconfig_s *)&adctimer);
+}
+#  endif /* 0 */
+#endif /* defined (CONFIG_TIVA_ADC) && defined (CONFIG_TIVA_TIMER) */