From 876c3ffffdce78b1cdc976b572fe1eca9b97fe44 Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Tue, 13 Dec 2022 00:07:20 -0500
Subject: [PATCH] stm32: No need to use hardware oversampling in stm32h7_adc.c

Not all chips implement hardware oversampling.  The software already
implements oversampling, and additional hardware oversampling is
unlikely to improve results.  Remove the hardware oversampling to
simplify the code.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
 src/stm32/stm32h7_adc.c | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/src/stm32/stm32h7_adc.c b/src/stm32/stm32h7_adc.c
index 61e0c764..3100d205 100644
--- a/src/stm32/stm32h7_adc.c
+++ b/src/stm32/stm32h7_adc.c
@@ -24,11 +24,6 @@
   #if CONFIG_MACH_STM32H723
     #define PCSEL                               PCSEL_RES0
   #endif
-
-  // Number of samples is 2^OVERSAMPLES_EXPONENT (exponent can be 0-10)
-  #define OVERSAMPLES_EXPONENT 3
-  #define OVERSAMPLES (1 << OVERSAMPLES_EXPONENT)
-
 #elif CONFIG_MACH_STM32L4
   #define ADCIN_BANK_SIZE                     (19)
   #define RCC_AHBENR_ADC                      (RCC->AHB2ENR)
@@ -37,9 +32,6 @@
   #define ADC_ATICKS                          (0b100)
   #define ADC_RES                             (0b00)
   #define ADC_TS                              (ADC12_COMMON)
-
-  #define OVERSAMPLES                         (0)
-
 #elif CONFIG_MACH_STM32G4
   #define ADCIN_BANK_SIZE                     (19)
   #define RCC_AHBENR_ADC                      (RCC->AHB2ENR)
@@ -49,8 +41,6 @@
   #define ADC_RES                             (0b00)
   #define ADC_TS                              (ADC12_COMMON)
   #define ADC_CCR_TSEN                        (ADC_CCR_VSENSESEL)
-
-  #define OVERSAMPLES                         (0)
 #endif
 
 #define ADC_TEMPERATURE_PIN 0xfe
@@ -301,21 +291,6 @@ gpio_adc_setup(uint32_t pin)
         if (!is_stm32h723_adc3) {
             MODIFY_REG(adc->CFGR, ADC_CFGR_RES_Msk, ADC_RES<<ADC_CFGR_RES_Pos);
         }
-#if CONFIG_MACH_STM32H7
-        // Set hardware oversampling
-        MODIFY_REG(adc->CFGR2, ADC_CFGR2_ROVSE_Msk, ADC_CFGR2_ROVSE);
-        if (is_stm32h723_adc3) {
-#ifdef ADC3_CFGR2_OVSR
-            MODIFY_REG(adc->CFGR2, ADC3_CFGR2_OVSR_Msk,
-                       (OVERSAMPLES_EXPONENT - 1) << ADC3_CFGR2_OVSR_Pos);
-#endif
-        } else {
-            MODIFY_REG(adc->CFGR2, ADC_CFGR2_OVSR_Msk,
-                       (OVERSAMPLES - 1) << ADC_CFGR2_OVSR_Pos);
-        }
-        MODIFY_REG(adc->CFGR2, ADC_CFGR2_OVSS_Msk,
-            OVERSAMPLES_EXPONENT << ADC_CFGR2_OVSS_Pos);
-#endif
     }
 
     if (pin == ADC_TEMPERATURE_PIN) {