[PATCH net-next 1/6] net: stmmac: add stmmac_set_tx_clk_gmii()

[Russell King (Oracle)]

Add a helper function for setting the transmit clock for GMII
interfaces. This handles 1G, 100M and 10M using the standard clock
rates of 125MHz, 25MHz and 2.5MHz.

Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
 .../ethernet/stmicro/stmmac/stmmac_platform.c | 25 +++++++++++++++++++
 .../ethernet/stmicro/stmmac/stmmac_platform.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 0f28795e581c..f7635ed2b255 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -700,6 +700,31 @@ EXPORT_SYMBOL_GPL(stmmac_probe_config_dt);
 EXPORT_SYMBOL_GPL(devm_stmmac_probe_config_dt);
 EXPORT_SYMBOL_GPL(stmmac_remove_config_dt);
 
+int stmmac_set_tx_clk_gmii(struct clk *tx_clk, unsigned int speed)
+{
+	unsigned long rate;
+
+	switch (speed) {
+	case SPEED_1000:
+		rate = 125000000;
+		break;
+
+	case SPEED_100:
+		rate = 25000000;
+		break;
+
+	case SPEED_10:
+		rate = 2500000;
+		break;
+
+	default:
+		return -ENOTSUPP;
+	}
+
+	return clk_set_rate(tx_clk, rate);
+}
+EXPORT_SYMBOL_GPL(stmmac_set_tx_clk_gmii);
+
 int stmmac_get_platform_resources(struct platform_device *pdev,
 				  struct stmmac_resources *stmmac_res)
 {
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.h
index c5565b2a70ac..8dc2287c6724 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.h
@@ -11,6 +11,7 @@
 
 #include "stmmac.h"
 
+int stmmac_set_tx_clk_gmii(struct clk *tx_clk, unsigned int speed);
 struct plat_stmmacenet_data *
 stmmac_probe_config_dt(struct platform_device *pdev, u8 *mac);
 struct plat_stmmacenet_data *
-- 
2.30.2