[net-next,PATCH v2 1/2] net: stmmac: dwmac-stm32: Add test to verify if ETHCK is used before checking clk rate

[Christophe Roullier]

When we want to use clock from RCC to clock Ethernet PHY (with ETHCK)
we need to check if value of clock rate is authorized.
If ETHCK is unused, the ETHCK frequency is 0Hz and validation fails.
It makes no sense to validate unused ETHCK, so skip the validation.

Fixes: 582ac134963e ("net: stmmac: dwmac-stm32: Separate out external clock rate validation")

Signed-off-by: Christophe Roullier <christophe.roullier at foss.st.com>
Reviewed-by: Marek Vasut <marex at denx.de>
Tested-by: Mark Brown <broonie at kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
index 23cf0a5b047f..d6a268237ca1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
@@ -206,6 +206,9 @@ static int stm32mp1_validate_ethck_rate(struct plat_stmmacenet_data *plat_dat)
 	struct stm32_dwmac *dwmac = plat_dat->bsp_priv;
 	const u32 clk_rate = clk_get_rate(dwmac->clk_eth_ck);
 
+	if (!dwmac->enable_eth_ck)
+		return 0;
+
 	switch (plat_dat->mac_interface) {
 	case PHY_INTERFACE_MODE_MII:
 	case PHY_INTERFACE_MODE_GMII:
-- 
2.25.1