- /* Change SPI clock to correct frequency, PLLP_OUT0 source */
- clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH,
- priv->freq);
+ /*
+ * Change SPI clock to correct frequency, PLLP_OUT0 source, falling
+ * back to the oscillator if that is too fast.
+ */
+ rate = clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH,
+ priv->freq);
+ if (rate > priv->freq + 100000) {
+ rate = clock_start_periph_pll(priv->periph_id, CLOCK_ID_OSC,
+ priv->freq);
+ if (rate != priv->freq) {
+ printf("Warning: SPI '%s' requested clock %u, actual clock %lu\n",
+ bus->name, priv->freq, rate);
+ }
+ }