stm32: Enable ADC support on stm32g0

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

3 files changed, 51 insertions, 12 deletions

diff --git a/src/stm32/Kconfig b/src/stm32/Kconfig
index 90bc63ae..7d9f6cb2 100644
--- a/src/stm32/Kconfig
+++ b/src/stm32/Kconfig
@@ -6,7 +6,7 @@ config STM32_SELECT
     bool
     default y
     select HAVE_GPIO
-    select HAVE_GPIO_ADC if !MACH_STM32G0
+    select HAVE_GPIO_ADC
     select HAVE_GPIO_I2C if !(MACH_STM32F031 || MACH_STM32H7)
     select HAVE_GPIO_SPI if !(MACH_STM32F031 || MACH_STM32G0)
     select HAVE_GPIO_HARD_PWM if MACH_STM32F1 || MACH_STM32F4 || MACH_STM32H7
diff --git a/src/stm32/Makefile b/src/stm32/Makefile
index 35a4cd39..5f2ad8ec 100644
--- a/src/stm32/Makefile
+++ b/src/stm32/Makefile
@@ -44,7 +44,7 @@ src-$(CONFIG_MACH_STM32F4) += stm32/stm32f4.c generic/armcm_timer.c
 src-$(CONFIG_MACH_STM32F4) += stm32/gpioperiph.c stm32/adc.c stm32/i2c.c
 src-$(CONFIG_MACH_STM32G0) += generic/timer_irq.c stm32/stm32f0_timer.c
 src-$(CONFIG_MACH_STM32G0) += stm32/stm32g0.c stm32/gpioperiph.c
-src-$(CONFIG_MACH_STM32G0) += stm32/stm32f0_i2c.c
+src-$(CONFIG_MACH_STM32G0) += stm32/stm32f0_adc.c stm32/stm32f0_i2c.c
 src-$(CONFIG_MACH_STM32H7) += ../lib/stm32h7/system_stm32h7xx.c
 src-$(CONFIG_MACH_STM32H7) += stm32/stm32h7.c generic/armcm_timer.c
 src-$(CONFIG_MACH_STM32H7) += stm32/gpioperiph.c stm32/stm32h7_adc.c
diff --git a/src/stm32/stm32f0_adc.c b/src/stm32/stm32f0_adc.c
index e3ae95e5..951d5bb1 100644
--- a/src/stm32/stm32f0_adc.c
+++ b/src/stm32/stm32f0_adc.c
@@ -21,11 +21,49 @@ DECL_ENUMERATION("pin", "ADC_TEMPERATURE", ADC_TEMPERATURE_PIN);
 static const uint8_t adc_pins[] = {
     GPIO('A', 0), GPIO('A', 1), GPIO('A', 2), GPIO('A', 3),
     GPIO('A', 4), GPIO('A', 5), GPIO('A', 6), GPIO('A', 7),
-    GPIO('B', 0), GPIO('B', 1), GPIO('C', 0), GPIO('C', 1),
+    GPIO('B', 0), GPIO('B', 1),
+#if CONFIG_MACH_STM32F0
+    GPIO('C', 0), GPIO('C', 1),
     GPIO('C', 2), GPIO('C', 3), GPIO('C', 4), GPIO('C', 5),
     ADC_TEMPERATURE_PIN
+#elif CONFIG_MACH_STM32G0
+    GPIO('B', 2), GPIO('B', 10),
+    ADC_TEMPERATURE_PIN, 0x00, 0x00,
+    GPIO('B', 11), GPIO('B', 12), GPIO('C', 4), GPIO('C', 5),
+#endif
 };
 
+// Setup and calibrate ADC on stm32f0 chips
+static void
+stm32f0_adc_setup(void)
+{
+#if CONFIG_MACH_STM32F0
+    #define CR_FLAGS 0
+    ADC_TypeDef *adc = ADC1;
+    // 100: 41.5 ADC clock cycles
+    adc->SMPR = 4 << ADC_SMPR_SMP_Pos;
+#endif
+}
+
+// Setup and calibrate ADC on stm32g0 chips
+static void
+stm32g0_adc_setup(void)
+{
+#if CONFIG_MACH_STM32G0
+    #define CR_FLAGS ADC_CR_ADVREGEN
+    ADC_TypeDef *adc = ADC1;
+    // 101: 39.5 ADC clock cycles
+    adc->SMPR = 5 << ADC_SMPR_SMP1_Pos;
+    adc->CFGR2 = 2 << ADC_CFGR2_CKMODE_Pos; // 16Mhz
+
+    // Enable voltage regulator
+    adc->CR = CR_FLAGS;
+    uint32_t end = timer_read_time() + timer_from_us(20);
+    while (timer_is_before(timer_read_time(), end))
+        ;
+#endif
+}
+
 struct gpio_adc
 gpio_adc_setup(uint32_t pin)
 {
@@ -41,18 +79,19 @@ gpio_adc_setup(uint32_t pin)
     // Enable the ADC
     if (!is_enabled_pclock(ADC1_BASE)) {
         enable_pclock(ADC1_BASE);
+        if (CONFIG_MACH_STM32F0)
+            stm32f0_adc_setup();
+        else if (CONFIG_MACH_STM32G0)
+            stm32g0_adc_setup();
 
+        // Start calibration and wait for completion
         ADC_TypeDef *adc = ADC1;
-        // 100: 41.5 ADC clock cycles
-        adc->SMPR = 4 << ADC_SMPR_SMP_Pos;
-
-        // start calibration and wait for completion
-        adc->CR = ADC_CR_ADCAL;
+        adc->CR = CR_FLAGS | ADC_CR_ADCAL;
         while (adc->CR & ADC_CR_ADCAL)
             ;
-
+        // Enable ADC
         adc->ISR = ADC_ISR_ADRDY;
-        adc->CR = ADC_CR_ADEN;
+        adc->CR = CR_FLAGS | ADC_CR_ADEN;
         while (!(adc->ISR & ADC_ISR_ADRDY))
             ;
     }
@@ -80,7 +119,7 @@ gpio_adc_sample(struct gpio_adc g)
         goto need_delay;
     }
     adc->CHSELR = g.chan;
-    adc->CR = ADC_CR_ADSTART;
+    adc->CR = CR_FLAGS | ADC_CR_ADSTART;
 
 need_delay:
     return timer_from_us(10);
@@ -102,7 +141,7 @@ gpio_adc_cancel_sample(struct gpio_adc g)
     irqstatus_t flag = irq_save();
     if (adc->CHSELR == g.chan) {
         if (adc->CR & ADC_CR_ADSTART)
-            adc->CR = ADC_CR_ADSTP;
+            adc->CR = CR_FLAGS | ADC_CR_ADSTP;
         if (adc->ISR & ADC_ISR_EOC)
             gpio_adc_read(g);
     }