From d09ba20cf3598f561013fc448076cf83ac7d5594 Mon Sep 17 00:00:00 2001
From: Giovanni Di Sirio <gdisirio@gmail.com>
Date: Sun, 20 Sep 2015 07:55:04 +0000
Subject: Differential mode for STM32F3xx ADC driver.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@8305 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 os/hal/ports/STM32/STM32F3xx/adc_lld.c | 22 ++++++++++++++++++++--
 os/hal/ports/STM32/STM32F3xx/adc_lld.h |  6 ++++--
 readme.txt                             |  1 +
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/os/hal/ports/STM32/STM32F3xx/adc_lld.c b/os/hal/ports/STM32/STM32F3xx/adc_lld.c
index 4b91cccb3..f19765b96 100644
--- a/os/hal/ports/STM32/STM32F3xx/adc_lld.c
+++ b/os/hal/ports/STM32/STM32F3xx/adc_lld.c
@@ -73,6 +73,10 @@ ADCDriver ADCD3;
 /* Driver local variables and types.                                         */
 /*===========================================================================*/
 
+static const ADCConfig default_config = {
+  difsel: 0
+};
+
 /*===========================================================================*/
 /* Driver local functions.                                                   */
 /*===========================================================================*/
@@ -366,6 +370,11 @@ void adc_lld_init(void) {
  */
 void adc_lld_start(ADCDriver *adcp) {
 
+  /* Handling the default configuration.*/
+  if (adcp->config == NULL) {
+    adcp->config = &default_config;
+  }
+
   /* If in stopped state then enables the ADC and DMA clocks.*/
   if (adcp->state == ADC_STOP) {
 #if STM32_ADC_USE_ADC1
@@ -402,6 +411,15 @@ void adc_lld_start(ADCDriver *adcp) {
     /* Clock source setting.*/
     adcp->adcc->CCR = STM32_ADC_ADC12_CLOCK_MODE | ADC_DMA_MDMA;
 
+
+    /* Differential channels setting.*/
+#if STM32_ADC_DUAL_MODE
+    adcp->adcm->DIFSEL = adcp->config->difsel;
+    adcp->adcs->DIFSEL = adcp->config->difsel;
+#else
+    adcp->adcm->DIFSEL = adcp->config->difsel;
+#endif
+
     /* Master ADC calibration.*/
     adc_lld_vreg_on(adcp);
     adc_lld_calibrate(adcp);
@@ -484,8 +502,8 @@ void adc_lld_start_conversion(ADCDriver *adcp) {
   dmaStreamSetTransactionSize(adcp->dmastp, ((uint32_t)grpp->num_channels/2) *
                                             (uint32_t)adcp->depth);
 #else
-    dmaStreamSetTransactionSize(adcp->dmastp, (uint32_t)grpp->num_channels *
-                                              (uint32_t)adcp->depth);
+  dmaStreamSetTransactionSize(adcp->dmastp, (uint32_t)grpp->num_channels *
+                                            (uint32_t)adcp->depth);
 #endif
   dmaStreamSetMode(adcp->dmastp, dmamode);
   dmaStreamEnable(adcp->dmastp);
diff --git a/os/hal/ports/STM32/STM32F3xx/adc_lld.h b/os/hal/ports/STM32/STM32F3xx/adc_lld.h
index ee6e2b5f3..668eb5047 100644
--- a/os/hal/ports/STM32/STM32F3xx/adc_lld.h
+++ b/os/hal/ports/STM32/STM32F3xx/adc_lld.h
@@ -452,10 +452,12 @@ typedef struct {
 
 /**
  * @brief   Driver configuration structure.
- * @note    It could be empty on some architectures.
  */
 typedef struct {
-  uint32_t                  dummy;
+  /**
+   * @brief   ADC DIFSEL register initialization data.
+   */
+  uint32_t                  difsel;
 } ADCConfig;
 
 /**
diff --git a/readme.txt b/readme.txt
index fda90e024..9f82c5cb8 100644
--- a/readme.txt
+++ b/readme.txt
@@ -73,6 +73,7 @@
 *****************************************************************************
 
 *** 3.1.0 ***
+- HAL: Added support for differential mode to the STM32F3xx ADC driver.
 - HAL: Experimental isochronous capability added to STM32 OTGv1 driver.
 - HAL: Modified the serial-USB driver to reject write/read attempts if the
        underlying USB is not in active state. In case of disconnection the
-- 
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