Merge branch 'spi-4.20' into spi-next

1 files changed, 24 insertions, 17 deletions

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index feed3db21c10..ee89ffb6dde8 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -513,7 +513,7 @@ EXPORT_SYMBOL(geni_se_resources_on);
  */
 int geni_se_clk_tbl_get(struct geni_se *se, unsigned long **tbl)
 {
-	unsigned long freq = 0;
+	long freq = 0;
 	int i;
 
 	if (se->clk_perf_tbl) {
@@ -529,7 +529,7 @@ int geni_se_clk_tbl_get(struct geni_se *se, unsigned long **tbl)
 
 	for (i = 0; i < MAX_CLK_PERF_LEVEL; i++) {
 		freq = clk_round_rate(se->clk, freq + 1);
-		if (!freq || freq == se->clk_perf_tbl[i - 1])
+		if (freq <= 0 || freq == se->clk_perf_tbl[i - 1])
 			break;
 		se->clk_perf_tbl[i] = freq;
 	}
@@ -544,16 +544,17 @@ EXPORT_SYMBOL(geni_se_clk_tbl_get);
  * @se:		Pointer to the concerned serial engine.
  * @req_freq:	Requested clock frequency.
  * @index:	Index of the resultant frequency in the table.
- * @res_freq:	Resultant frequency which matches or is closer to the
- *		requested frequency.
+ * @res_freq:	Resultant frequency of the source clock.
  * @exact:	Flag to indicate exact multiple requirement of the requested
  *		frequency.
  *
- * This function is called by the protocol drivers to determine the matching
- * or exact multiple of the requested frequency, as provided by the serial
- * engine clock in order to meet the performance requirements. If there is
- * no matching or exact multiple of the requested frequency found, then it
- * selects the closest floor frequency, if exact flag is not set.
+ * This function is called by the protocol drivers to determine the best match
+ * of the requested frequency as provided by the serial engine clock in order
+ * to meet the performance requirements.
+ *
+ * If we return success:
+ * - if @exact is true  then @res_freq / <an_integer> == @req_freq
+ * - if @exact is false then @res_freq / <an_integer> <= @req_freq
  *
  * Return: 0 on success, standard Linux error codes on failure.
  */
@@ -564,6 +565,9 @@ int geni_se_clk_freq_match(struct geni_se *se, unsigned long req_freq,
 	unsigned long *tbl;
 	int num_clk_levels;
 	int i;
+	unsigned long best_delta;
+	unsigned long new_delta;
+	unsigned int divider;
 
 	num_clk_levels = geni_se_clk_tbl_get(se, &tbl);
 	if (num_clk_levels < 0)
@@ -572,18 +576,21 @@ int geni_se_clk_freq_match(struct geni_se *se, unsigned long req_freq,
 	if (num_clk_levels == 0)
 		return -EINVAL;
 
-	*res_freq = 0;
+	best_delta = ULONG_MAX;
 	for (i = 0; i < num_clk_levels; i++) {
-		if (!(tbl[i] % req_freq)) {
+		divider = DIV_ROUND_UP(tbl[i], req_freq);
+		new_delta = req_freq - tbl[i] / divider;
+		if (new_delta < best_delta) {
+			/* We have a new best! */
 			*index = i;
 			*res_freq = tbl[i];
-			return 0;
-		}
 
-		if (!(*res_freq) || ((tbl[i] > *res_freq) &&
-				     (tbl[i] < req_freq))) {
-			*index = i;
-			*res_freq = tbl[i];
+			/* If the new best is exact then we're done */
+			if (new_delta == 0)
+				return 0;
+
+			/* Record how close we got */
+			best_delta = new_delta;
 		}
 	}