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path: root/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
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Diffstat (limited to 'drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c')
-rw-r--r--drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
index c72ee759aae5..f2946bea0bc2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
@@ -211,6 +211,7 @@ static int thead_dwmac_probe(struct platform_device *pdev)
struct stmmac_resources stmmac_res;
struct plat_stmmacenet_data *plat;
struct thead_dwmac *dwmac;
+ struct clk *apb_clk;
void __iomem *apb;
int ret;
@@ -224,6 +225,19 @@ static int thead_dwmac_probe(struct platform_device *pdev)
return dev_err_probe(&pdev->dev, PTR_ERR(plat),
"dt configuration failed\n");
+ /*
+ * The APB clock is essential for accessing glue registers. However,
+ * old devicetrees don't describe it correctly. We continue to probe
+ * and emit a warning if it isn't present.
+ */
+ apb_clk = devm_clk_get_enabled(&pdev->dev, "apb");
+ if (PTR_ERR(apb_clk) == -ENOENT)
+ dev_warn(&pdev->dev,
+ "cannot get apb clock, link may break after speed changes\n");
+ else if (IS_ERR(apb_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(apb_clk),
+ "failed to get apb clock\n");
+
dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
if (!dwmac)
return -ENOMEM;