serial: stm32x7: add clk_get_rate() support

Replace proprietary clock_get() by clk_get_rate()
The stm32x7 serial driver is now "generic" and can be used
by other STM32 SoCs.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vikas MANOCHA <vikas.manocha@st.com>

drivers/serial/serial_stm32x7.c

@@ -19,16 +19,9 @@ 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, mantissa, fraction, oversampling;
+	u32 int_div, mantissa, fraction, oversampling;
 
-	if (((u32)usart & STM32_BUS_MASK) == APB1_PERIPH_BASE)
-		clock = clock_get(CLOCK_APB1);
-	else if (((u32)usart & STM32_BUS_MASK) == APB2_PERIPH_BASE)
-		clock = clock_get(CLOCK_APB2);
-	else
-		return -EINVAL;
-
-	int_div = DIV_ROUND_CLOSEST(clock, baudrate);
+	int_div = DIV_ROUND_CLOSEST(plat->clock_rate, baudrate);
 
 	if (int_div < 16) {
 		oversampling = 8;
@@ -101,6 +94,12 @@ static int stm32_serial_probe(struct udevice *dev)
 	}
 #endif
 
+	plat->clock_rate = clk_get_rate(&clk);
+	if (plat->clock_rate < 0) {
+		clk_disable(&clk);
+		return plat->clock_rate;
+	};
+
 	/* Disable usart-> disable overrun-> enable usart */
 	clrbits_le32(&usart->cr1, USART_CR1_RE | USART_CR1_TE | USART_CR1_UE);
 	setbits_le32(&usart->cr3, USART_CR3_OVRDIS);

drivers/serial/serial_stm32x7.h

@@ -25,7 +25,7 @@ struct stm32_usart {
 /* Information about a serial port */
 struct stm32x7_serial_platdata {
 	struct stm32_usart *base;  /* address of registers in physical memory */
-	unsigned int clock;
+	unsigned long int clock_rate;
 };
 
 #define USART_CR1_OVER8			(1 << 15)