diff options
| -rw-r--r-- | drivers/serial/serial_stm32x7.c | 21 | ||||
| -rw-r--r-- | drivers/serial/serial_stm32x7.h | 3 |
2 files changed, 17 insertions, 7 deletions
diff --git a/drivers/serial/serial_stm32x7.c b/drivers/serial/serial_stm32x7.c index 7693159..61e8167 100644 --- a/drivers/serial/serial_stm32x7.c +++ b/drivers/serial/serial_stm32x7.c @@ -20,7 +20,7 @@ static int stm32_serial_setbrg(struct udevice *dev, int baudrate) { struct stm32x7_serial_platdata *plat = dev->platdata; struct stm32_usart *const usart = plat->base; - u32 clock, int_div, frac_div, tmp; + u32 clock, int_div, mantissa, fraction, oversampling; if (((u32)usart & STM32_BUS_MASK) == APB1_PERIPH_BASE) clock = clock_get(CLOCK_APB1); @@ -29,11 +29,20 @@ static int stm32_serial_setbrg(struct udevice *dev, int baudrate) else return -EINVAL; - int_div = (25 * clock) / (4 * baudrate); - tmp = ((int_div / 100) << USART_BRR_M_SHIFT) & USART_BRR_M_MASK; - frac_div = int_div - (100 * (tmp >> USART_BRR_M_SHIFT)); - tmp |= (((frac_div * 16) + 50) / 100) & USART_BRR_F_MASK; - writel(tmp, &usart->brr); + int_div = DIV_ROUND_CLOSEST(clock, baudrate); + + if (int_div < 16) { + oversampling = 8; + setbits_le32(&usart->cr1, USART_CR1_OVER8); + } else { + oversampling = 16; + clrbits_le32(&usart->cr1, USART_CR1_OVER8); + } + + mantissa = (int_div / oversampling) << USART_BRR_M_SHIFT; + fraction = int_div % oversampling; + + writel(mantissa | fraction, &usart->brr); return 0; } diff --git a/drivers/serial/serial_stm32x7.h b/drivers/serial/serial_stm32x7.h index 8c02548..facfdba 100644 --- a/drivers/serial/serial_stm32x7.h +++ b/drivers/serial/serial_stm32x7.h @@ -23,8 +23,9 @@ struct stm32_usart { }; -#define USART_CR1_RE (1 << 2) +#define USART_CR1_OVER8 (1 << 15) #define USART_CR1_TE (1 << 3) +#define USART_CR1_RE (1 << 2) #define USART_CR1_UE (1 << 0) #define USART_CR3_OVRDIS (1 << 12) |