stm32: Add Hardware PWM support for STM32G0 processors (#5714)

Uses existing common code for STM32. Adds a table for device-
specific PWM mappings. Adds support for enabling all TIM timer
devices. Makes it a runtime error to enable devices the code
doesn't know how to enable.

I have verified performance of the fan pins (PC6, PC7, PB15)
on the SKR Mini E3 V3.

Signed-off-by: Ben Jackson <ben@ben.com>

src/stm32/Kconfig

@@ -9,7 +9,7 @@ config STM32_SELECT
     select HAVE_GPIO_ADC
     select HAVE_GPIO_I2C if !(MACH_STM32F031 || MACH_STM32H7)
     select HAVE_GPIO_SPI if !MACH_STM32F031
-    select HAVE_GPIO_HARD_PWM if MACH_STM32F1 || MACH_STM32F4 || MACH_STM32H7
+    select HAVE_GPIO_HARD_PWM if MACH_STM32F1 || MACH_STM32F4 || MACH_STM32G0 || MACH_STM32H7
     select HAVE_GPIO_BITBANGING if !MACH_STM32F031
     select HAVE_STRICT_TIMING
     select HAVE_CHIPID

src/stm32/hard_pwm.c

@@ -102,6 +102,53 @@ static const struct gpio_pwm_info pwm_regs[] = {
     {TIM9,  GPIO('E',  6),  2, GPIO_FUNCTION(3)},
     {TIM10, GPIO('B',  8),  1, GPIO_FUNCTION(3)},
     {TIM11, GPIO('B',  9),  1, GPIO_FUNCTION(3)}
+#elif CONFIG_MACH_STM32G0
+    {TIM15, GPIO('A',  2), 1, GPIO_FUNCTION(5)},
+    {TIM15, GPIO('A',  3), 2, GPIO_FUNCTION(5)},
+    {TIM14, GPIO('A',  4), 1, GPIO_FUNCTION(4)},
+    {TIM3,  GPIO('A',  6), 1, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('A',  7), 2, GPIO_FUNCTION(1)},
+    {TIM1,  GPIO('A',  8), 1, GPIO_FUNCTION(2)},
+    {TIM1,  GPIO('A',  9), 2, GPIO_FUNCTION(2)},
+    {TIM1,  GPIO('A', 10), 3, GPIO_FUNCTION(2)},
+    {TIM1,  GPIO('A', 11), 4, GPIO_FUNCTION(2)},
+    {TIM3,  GPIO('B',  0), 3, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('B',  1), 4, GPIO_FUNCTION(1)},
+    {TIM1,  GPIO('B',  3), 2, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('B',  4), 1, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('B',  5), 2, GPIO_FUNCTION(1)},
+    {TIM4,  GPIO('B',  6), 1, GPIO_FUNCTION(9)},
+    {TIM4,  GPIO('B',  7), 2, GPIO_FUNCTION(9)},
+    {TIM4,  GPIO('B',  8), 3, GPIO_FUNCTION(9)},
+    {TIM4,  GPIO('B',  9), 4, GPIO_FUNCTION(9)},
+    {TIM15, GPIO('B', 14), 1, GPIO_FUNCTION(5)},
+    {TIM15, GPIO('B', 15), 2, GPIO_FUNCTION(5)},
+    {TIM15, GPIO('C',  1), 1, GPIO_FUNCTION(2)},
+    {TIM15, GPIO('C',  2), 2, GPIO_FUNCTION(2)},
+    {TIM3,  GPIO('C',  6), 1, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('C',  7), 2, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('C',  8), 3, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('C',  9), 4, GPIO_FUNCTION(1)},
+    {TIM1,  GPIO('C', 10), 3, GPIO_FUNCTION(2)},
+    {TIM1,  GPIO('C', 11), 4, GPIO_FUNCTION(2)},
+    {TIM14, GPIO('C', 12), 1, GPIO_FUNCTION(2)},
+    {TIM16, GPIO('D',  0), 1, GPIO_FUNCTION(2)},
+    {TIM17, GPIO('D',  1), 1, GPIO_FUNCTION(2)},
+    {TIM4,  GPIO('D', 12), 1, GPIO_FUNCTION(2)},
+    {TIM4,  GPIO('D', 13), 2, GPIO_FUNCTION(2)},
+    {TIM4,  GPIO('D', 14), 3, GPIO_FUNCTION(2)},
+    {TIM4,  GPIO('D', 15), 4, GPIO_FUNCTION(2)},
+    {TIM3,  GPIO('E',  3), 1, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('E',  4), 2, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('E',  5), 3, GPIO_FUNCTION(1)},
+    {TIM3,  GPIO('E',  6), 4, GPIO_FUNCTION(1)},
+    {TIM1,  GPIO('E',  9), 1, GPIO_FUNCTION(1)},
+    {TIM1,  GPIO('E', 11), 2, GPIO_FUNCTION(1)},
+    {TIM1,  GPIO('E', 13), 3, GPIO_FUNCTION(1)},
+    {TIM1,  GPIO('E', 14), 4, GPIO_FUNCTION(1)},
+    {TIM14, GPIO('F',  0), 1, GPIO_FUNCTION(2)},
+    {TIM15, GPIO('F', 12), 1, GPIO_FUNCTION(0)},
+    {TIM15, GPIO('F', 13), 2, GPIO_FUNCTION(0)},
 #elif CONFIG_MACH_STM32H7
     {TIM2, GPIO('A', 0),  1, GPIO_FUNCTION(1)},
     {TIM2, GPIO('A', 5),  1, GPIO_FUNCTION(1)},
@@ -234,7 +281,7 @@ gpio_pwm_setup(uint8_t pin, uint32_t cycle_time, uint8_t val){
     }
     // Enable PWM output
     p->timer->CR1 |= TIM_CR1_CEN;
-#if CONFIG_MACH_STM32H7
+#if CONFIG_MACH_STM32H7 || CONFIG_MACH_STM32G0
     p->timer->BDTR |= TIM_BDTR_MOE;
 #endif
     return channel;

src/stm32/stm32g0.c

@@ -38,14 +38,29 @@ lookup_clock_line(uint32_t periph_base)
         return (struct cline){.en=&RCC->APBENR1,.rst=&RCC->APBRSTR1,.bit=1<<13};
     if (periph_base == CRS_BASE)
         return (struct cline){.en=&RCC->APBENR1,.rst=&RCC->APBRSTR1,.bit=1<<16};
+    if (periph_base == TIM1_BASE)
+        return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<11};
     if (periph_base == SPI1_BASE)
         return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<12};
     if (periph_base == USART1_BASE)
         return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<14};
+    if (periph_base == TIM14_BASE)
+        return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<15};
+    if (periph_base == TIM15_BASE)
+        return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<16};
+    if (periph_base == TIM16_BASE)
+        return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<17};
+    if (periph_base == TIM17_BASE)
+        return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<18};
     if (periph_base == ADC1_BASE)
         return (struct cline){.en=&RCC->APBENR2,.rst=&RCC->APBRSTR2,.bit=1<<20};
+    if (periph_base >= APBPERIPH_BASE && periph_base <= LPTIM1_BASE)
+    {
         uint32_t bit = 1 << ((periph_base - APBPERIPH_BASE) / 0x400);
         return (struct cline){.en=&RCC->APBENR1, .rst=&RCC->APBRSTR1, .bit=bit};
+    }
+    // unknown peripheral. returning .bit=0 makes this a no-op
+    return (struct cline){.en=&RCC->APBENR1, .rst=NULL, .bit=0};
 }
 
 // Return the frequency of the given peripheral clock