From 3796a319599e84b58886ec6f733277bfe4f1a747 Mon Sep 17 00:00:00 2001
From: Kevin O'Connor <kevin@koconnor.net>
Date: Mon, 25 Jul 2022 10:21:29 -0400
Subject: [PATCH] stm32: Add CCRDY check to stm32g0 adc

The stm32g0 specification states that it is required to wait for the
CCRDY flag to be raised after changing the channel configuration.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
 src/stm32/stm32f0_adc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/stm32/stm32f0_adc.c b/src/stm32/stm32f0_adc.c
index 8f27dce7..f46ccbde 100644
--- a/src/stm32/stm32f0_adc.c
+++ b/src/stm32/stm32f0_adc.c
@@ -119,7 +119,16 @@ gpio_adc_sample(struct gpio_adc g)
             return 0;
         goto need_delay;
     }
+#if CONFIG_MACH_STM32G0
+    if (adc->CHSELR != g.chan) {
+        adc->ISR = ADC_ISR_CCRDY;
+        adc->CHSELR = g.chan;
+        while (!(adc->ISR & ADC_ISR_CCRDY))
+            ;
+    }
+#else
     adc->CHSELR = g.chan;
+#endif
     adc->CR = CR_FLAGS | ADC_CR_ADSTART;
 
 need_delay: