---

yaml
---
r: 271171
b: refs/heads/master
c: 0379b2a
h: refs/heads/master
i:
  271169: ff4118b
  271167: 86881ae
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b181565ee6a0f894bd6a134b9e5bed2966bdf9b3
+refs/heads/master: 0379b2a33a8a03d4ad1036ef646419dbdf1ac15a

trunk/drivers/spi/spi-pl022.c

@@ -1790,67 +1790,67 @@ static int pl022_transfer(struct spi_device *spi, struct spi_message *msg)
 	return 0;
 }
 
-static int calculate_effective_freq(struct pl022 *pl022,
-				    int freq,
-				    struct ssp_clock_params *clk_freq)
+static inline u32 spi_rate(u32 rate, u16 cpsdvsr, u16 scr)
+{
+	return rate / (cpsdvsr * (1 + scr));
+}
+
+static int calculate_effective_freq(struct pl022 *pl022, int freq, struct
+				    ssp_clock_params * clk_freq)
 {
 	/* Lets calculate the frequency parameters */
-	u16 cpsdvsr = 2;
-	u16 scr = 0;
-	bool freq_found = false;
-	u32 rate;
-	u32 max_tclk;
-	u32 min_tclk;
+	u16 cpsdvsr = CPSDVR_MIN, scr = SCR_MIN;
+	u32 rate, max_tclk, min_tclk, best_freq = 0, best_cpsdvsr = 0,
+		best_scr = 0, tmp, found = 0;
 
 	rate = clk_get_rate(pl022->clk);
 	/* cpsdvscr = 2 & scr 0 */
-	max_tclk = (rate / (CPSDVR_MIN * (1 + SCR_MIN)));
+	max_tclk = spi_rate(rate, CPSDVR_MIN, SCR_MIN);
 	/* cpsdvsr = 254 & scr = 255 */
-	min_tclk = (rate / (CPSDVR_MAX * (1 + SCR_MAX)));
-
-	if ((freq <= max_tclk) && (freq >= min_tclk)) {
-		while (cpsdvsr <= CPSDVR_MAX && !freq_found) {
-			while (scr <= SCR_MAX && !freq_found) {
-				if ((rate /
-				     (cpsdvsr * (1 + scr))) > freq)
-					scr += 1;
-				else {
-					/*
-					 * This bool is made true when
-					 * effective frequency >=
-					 * target frequency is found
-					 */
-					freq_found = true;
-					if ((rate /
-					     (cpsdvsr * (1 + scr))) != freq) {
-						if (scr == SCR_MIN) {
-							cpsdvsr -= 2;
-							scr = SCR_MAX;
-						} else
-							scr -= 1;
-					}
-				}
-			}
-			if (!freq_found) {
-				cpsdvsr += 2;
-				scr = SCR_MIN;
-			}
-		}
-		if (cpsdvsr != 0) {
-			dev_dbg(&pl022->adev->dev,
-				"SSP Effective Frequency is %u\n",
-				(rate / (cpsdvsr * (1 + scr))));
-			clk_freq->cpsdvsr = (u8) (cpsdvsr & 0xFF);
-			clk_freq->scr = (u8) (scr & 0xFF);
-			dev_dbg(&pl022->adev->dev,
-				"SSP cpsdvsr = %d, scr = %d\n",
-				clk_freq->cpsdvsr, clk_freq->scr);
-		}
-	} else {
+	min_tclk = spi_rate(rate, CPSDVR_MAX, SCR_MAX);
+
+	if (!((freq <= max_tclk) && (freq >= min_tclk))) {
 		dev_err(&pl022->adev->dev,
 			"controller data is incorrect: out of range frequency");
 		return -EINVAL;
 	}
+
+	/*
+	 * best_freq will give closest possible available rate (<= requested
+	 * freq) for all values of scr & cpsdvsr.
+	 */
+	while ((cpsdvsr <= CPSDVR_MAX) && !found) {
+		while (scr <= SCR_MAX) {
+			tmp = spi_rate(rate, cpsdvsr, scr);
+
+			if (tmp > freq)
+				scr++;
+			/*
+			 * If found exact value, update and break.
+			 * If found more closer value, update and continue.
+			 */
+			else if ((tmp == freq) || (tmp > best_freq)) {
+				best_freq = tmp;
+				best_cpsdvsr = cpsdvsr;
+				best_scr = scr;
+
+				if (tmp == freq)
+					break;
+			}
+			scr++;
+		}
+		cpsdvsr += 2;
+		scr = SCR_MIN;
+	}
+
+	clk_freq->cpsdvsr = (u8) (best_cpsdvsr & 0xFF);
+	clk_freq->scr = (u8) (best_scr & 0xFF);
+	dev_dbg(&pl022->adev->dev,
+		"SSP Target Frequency is: %u, Effective Frequency is %u\n",
+		freq, best_freq);
+	dev_dbg(&pl022->adev->dev, "SSP cpsdvsr = %d, scr = %d\n",
+		clk_freq->cpsdvsr, clk_freq->scr);
+
 	return 0;
 }