Added standard clock setup routines.

Thanks to Thomas Otto for pointing out problems with the clock code in
examples and his clock routine implementations. Based on that the most
common clock combination routines were added to the library and all
routines in examples setting up the clock replaced with calls to that
functions.

examples/mb525/pwmleds/pwmleds.c

@@ -236,26 +236,9 @@ static const u16 gamma_table_3_0[] = {
 };
 #endif
 
-/* Set STM32 to 72 MHz. */
 void clock_setup(void)
 {
-	/* Select HSI as SYSCLK source. */
-	rcc_set_sysclk_source(SW_SYSCLKSEL_HSICLK);
-
-	/* Set the PLL multiplication factor to 9. */
-	rcc_set_pll_multiplication_factor(PLLMUL_PLL_CLK_MUL9);
-
-	/* Select HSI/2 as PLL source. */
-	rcc_set_pll_source(PLLSRC_HSI_CLK_DIV2);
-
-	rcc_set_pllxtpre(PLLXTPRE_HSE_CLK_DIV2);
-
-	/* Enable PLL oscillator and wait for it to stabilize. */
-	rcc_osc_on(PLL);
-	rcc_wait_for_osc_ready(PLL);
-
-	/* Select PLL as SYSCLK source. */
-	rcc_set_sysclk_source(SW_SYSCLKSEL_PLLCLK);
+	rcc_clock_setup_in_hse_8mhz_out_72mhz();
 
 	/* Enable TIM3 clock. */
 	rcc_peripheral_enable_clock(&RCC_APB1ENR, TIM3EN);