drivers: spi: siwx91x: Simplify gspi_siwx91x_pick_lower_freq()

Since actual_hz is no more needed, we can simplify
gspi_siwx91x_pick_lower_freq().

Signed-off-by: Jérôme Pouiller <[email protected]>
Upstream-status: pr <zephyrproject-rtos#100762>

Author: jerome-pouiller

drivers/spi/spi_silabs_siwx91x_gspi.c

@@ -76,27 +76,17 @@ static bool spi_siwx91x_is_dma_enabled_instance(const struct device *dev)
 #endif
 }
 
-void gspi_siwx91x_pick_lower_freq(uint32_t clock_hz, uint32_t requested_hz, uint32_t *actual_hz_out,
-				  uint32_t *div_out)
+static uint32_t gspi_siwx91x_get_divider(uint32_t clock_hz, uint32_t requested_hz)
 {
-	/* Calculate divider that ensures freq <= requested */
 	uint32_t divider = DIV_ROUND_UP(clock_hz, 2 * requested_hz);
-	uint32_t actual_hz;
+	uint32_t actual_freq = clock_hz / (2U * divider);
 
-	if (divider == 0U) {
-		divider = 1U;
+	if (requested_hz != actual_freq) {
+		LOG_INF("Requested %u Hz, programmed %u Hz (divider=%u)",
+			requested_hz, actual_freq, divider);
 	}
 
-	/* Compute the actual achievable frequency */
-	actual_hz = clock_hz / (2U * divider);
-
-	if (actual_hz_out) {
-		*actual_hz_out = actual_hz;
-	}
-
-	if (div_out) {
-		*div_out = divider;
-	}
+	return divider;
 }
 
 static int gspi_siwx91x_config(const struct device *dev, const struct spi_config *spi_cfg,
@@ -105,7 +95,6 @@ static int gspi_siwx91x_config(const struct device *dev, const struct spi_config
 	__maybe_unused struct gspi_siwx91x_data *data = dev->data;
 	const struct gspi_siwx91x_config *cfg = dev->config;
 	uint32_t clk_div_factor;
-	uint32_t actual_freq;
 	uint32_t clock_rate;
 	int ret;
 	__maybe_unused int channel_filter;
@@ -142,13 +131,7 @@ static int gspi_siwx91x_config(const struct device *dev, const struct spi_config
 		if (ret) {
 			return ret;
 		}
-
-		gspi_siwx91x_pick_lower_freq(clock_rate, spi_cfg->frequency, &actual_freq,
-					     &clk_div_factor);
-		if (spi_cfg->frequency != actual_freq) {
-			LOG_INF("Requested %u Hz, programmed %u Hz (divider=%u)",
-				spi_cfg->frequency, actual_freq, clk_div_factor);
-		}
+		clk_div_factor = gspi_siwx91x_get_divider(clock_rate, spi_cfg->frequency);
 	}
 
 	/* Set the clock divider factor */