[PATCH net-next 1/8] net: stmmac: mdio: convert MDC clock divisor selection to tables

["Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>]

Convert the MDC clock divisor selection to tabular format.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_mdio.c | 98 ++++++++++++-------
 1 file changed, 62 insertions(+), 36 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index 485a0d790baa..c4123d2260bd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
@@ -473,6 +473,52 @@ void stmmac_pcs_clean(struct net_device *ndev)
 	priv->hw->xpcs = NULL;
 }
 
+struct stmmac_clk_rate {
+	unsigned long rate;
+	u8 cr;
+};
+
+/* The standard clk_csr_i to GMII_Address CR field mapping. The rate provided
+ * in this table is the exclusive maximum frequency for the divisor. The
+ * comments for each entry give the divisor and the resulting range of MDC
+ * clock frequencies.
+ */
+static const struct stmmac_clk_rate stmmac_std_csr_to_mdc[] = {
+	{ CSR_F_35M, STMMAC_CSR_20_35M },
+	{ CSR_F_60M, STMMAC_CSR_35_60M },
+	{ CSR_F_100M, STMMAC_CSR_60_100M },
+	{ CSR_F_150M, STMMAC_CSR_100_150M },
+	{ CSR_F_250M, STMMAC_CSR_150_250M },
+	{ CSR_F_300M, STMMAC_CSR_250_300M },
+	{ CSR_F_500M, STMMAC_CSR_300_500M },
+	{ CSR_F_800M, STMMAC_CSR_500_800M },
+	{ },
+};
+
+/* The sun8i clk_csr_i to GMII_Address CR field mapping uses rate as the
+ * exclusive minimum frequency for the divisor. Note that the last entry
+ * is valid and also acts as the sentinel.
+ */
+static const struct stmmac_clk_rate stmmac_sun8i_csr_to_mdc[] = {
+	{ 160000000, 3 },
+	{ 80000000, 2 },
+	{ 40000000, 1 },
+	{ 0, 0 },
+};
+
+/* The xgmac clk_csr_i to GMII_Address CR field mapping similarly uses rate
+ * as the exclusive minimum frequency for the divisor, and again the last
+ * entry is valid and also the sentinel.
+ */
+static const struct stmmac_clk_rate stmmac_xgmac_csr_to_mdc[] = {
+	{ 400000000, 5 },
+	{ 350000000, 4 },
+	{ 300000000, 3 },
+	{ 250000000, 2 },
+	{ 150000000, 1 },
+	{ 0, 0 },
+};
+
 /**
  * stmmac_clk_csr_set - dynamically set the MDC clock
  * @priv: driver private structure
@@ -490,6 +536,7 @@ static u32 stmmac_clk_csr_set(struct stmmac_priv *priv)
 {
 	unsigned long clk_rate;
 	u32 value = ~0;
+	int i;
 
 	clk_rate = clk_get_rate(priv->plat->stmmac_clk);
 
@@ -500,47 +547,26 @@ static u32 stmmac_clk_csr_set(struct stmmac_priv *priv)
 	 * the frequency of clk_csr_i. So we do not change the default
 	 * divider.
 	 */
-	if (clk_rate < CSR_F_35M)
-		value = STMMAC_CSR_20_35M;
-	else if (clk_rate < CSR_F_60M)
-		value = STMMAC_CSR_35_60M;
-	else if (clk_rate < CSR_F_100M)
-		value = STMMAC_CSR_60_100M;
-	else if (clk_rate < CSR_F_150M)
-		value = STMMAC_CSR_100_150M;
-	else if (clk_rate < CSR_F_250M)
-		value = STMMAC_CSR_150_250M;
-	else if (clk_rate <= CSR_F_300M)
-		value = STMMAC_CSR_250_300M;
-	else if (clk_rate < CSR_F_500M)
-		value = STMMAC_CSR_300_500M;
-	else if (clk_rate < CSR_F_800M)
-		value = STMMAC_CSR_500_800M;
+	for (i = 0; stmmac_std_csr_to_mdc[i].rate; i++)
+		if (clk_rate < stmmac_std_csr_to_mdc[i].rate) {
+			value = stmmac_std_csr_to_mdc[i].cr;
+			break;
+		}
 
 	if (priv->plat->flags & STMMAC_FLAG_HAS_SUN8I) {
-		if (clk_rate > 160000000)
-			value = 0x03;
-		else if (clk_rate > 80000000)
-			value = 0x02;
-		else if (clk_rate > 40000000)
-			value = 0x01;
-		else
-			value = 0;
+		/* Note the different test - this is intentional. */
+		for (i = 0; stmmac_sun8i_csr_to_mdc[i].rate; i++)
+			if (clk_rate > stmmac_sun8i_csr_to_mdc[i].rate)
+				break;
+		value = stmmac_sun8i_csr_to_mdc[i].cr;
 	}
 
 	if (priv->plat->core_type == DWMAC_CORE_XGMAC) {
-		if (clk_rate > 400000000)
-			value = 0x5;
-		else if (clk_rate > 350000000)
-			value = 0x4;
-		else if (clk_rate > 300000000)
-			value = 0x3;
-		else if (clk_rate > 250000000)
-			value = 0x2;
-		else if (clk_rate > 150000000)
-			value = 0x1;
-		else
-			value = 0x0;
+		/* Note the different test - this is intentional. */
+		for (i = 0; stmmac_xgmac_csr_to_mdc[i].rate; i++)
+			if (clk_rate > stmmac_xgmac_csr_to_mdc[i].rate)
+				break;
+		value = stmmac_xgmac_csr_to_mdc[i].cr;
 	}
 
 	return value;
-- 
2.47.3