[net: ethernet: stmmac: some fixes and optimizations 1/5] net: ethernet: stmmac: Add support for syscfg clock

[Christophe Roullier <christophe.roullier@xxxxxx>]

Add optional support for syscfg clock in dwmac-stm32.c
Now Syscfg clock is activated automatically when syscfg
registers are used

Signed-off-by: Christophe Roullier <christophe.roullier@xxxxxx>
---
 .../net/ethernet/stmicro/stmmac/dwmac-stm32.c | 36 +++++++++++++------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
index 4ef041bdf6a1..7e6619868cc1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
@@ -152,23 +152,32 @@ static int stm32mp1_clk_prepare(struct stm32_dwmac *dwmac, bool prepare)
 	int ret = 0;
 
 	if (prepare) {
-		ret = clk_prepare_enable(dwmac->syscfg_clk);
-		if (ret)
-			return ret;
-
+		if (dwmac->syscfg_clk) {
+			ret = clk_prepare_enable(dwmac->syscfg_clk);
+			if (ret)
+				return ret;
+		}
 		if (dwmac->clk_eth_ck) {
 			ret = clk_prepare_enable(dwmac->clk_eth_ck);
 			if (ret) {
-				clk_disable_unprepare(dwmac->syscfg_clk);
+				if (dwmac->syscfg_clk)
+					goto unprepare_syscfg;
 				return ret;
 			}
 		}
 	} else {
-		clk_disable_unprepare(dwmac->syscfg_clk);
+		if (dwmac->syscfg_clk)
+			clk_disable_unprepare(dwmac->syscfg_clk);
+
 		if (dwmac->clk_eth_ck)
 			clk_disable_unprepare(dwmac->clk_eth_ck);
 	}
 	return ret;
+
+unprepare_syscfg:
+	clk_disable_unprepare(dwmac->syscfg_clk);
+
+	return ret;
 }
 
 static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
@@ -296,7 +305,7 @@ static int stm32mp1_parse_data(struct stm32_dwmac *dwmac,
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct device_node *np = dev->of_node;
-	int err = 0;
+	int err;
 
 	/* Gigabit Ethernet 125MHz clock selection. */
 	dwmac->eth_clk_sel_reg = of_property_read_bool(np, "st,eth-clk-sel");
@@ -320,13 +329,17 @@ static int stm32mp1_parse_data(struct stm32_dwmac *dwmac,
 		return PTR_ERR(dwmac->clk_ethstp);
 	}
 
-	/*  Clock for sysconfig */
+	/*  Optional Clock for sysconfig */
 	dwmac->syscfg_clk = devm_clk_get(dev, "syscfg-clk");
 	if (IS_ERR(dwmac->syscfg_clk)) {
-		dev_err(dev, "No syscfg clock provided...\n");
-		return PTR_ERR(dwmac->syscfg_clk);
+		err = PTR_ERR(dwmac->syscfg_clk);
+		if (err != -ENOENT)
+			return err;
+		dwmac->syscfg_clk = NULL;
 	}
 
+	err = 0;
+
 	/* Get IRQ information early to have an ability to ask for deferred
 	 * probe if needed before we went too far with resource allocation.
 	 */
@@ -436,7 +449,8 @@ static int stm32mp1_suspend(struct stm32_dwmac *dwmac)
 		return ret;
 
 	clk_disable_unprepare(dwmac->clk_tx);
-	clk_disable_unprepare(dwmac->syscfg_clk);
+	if (dwmac->syscfg_clk)
+		clk_disable_unprepare(dwmac->syscfg_clk);
 	if (dwmac->clk_eth_ck)
 		clk_disable_unprepare(dwmac->clk_eth_ck);
 
-- 
2.17.1