[PATCH] drm/sun4i: frontend: fix clock leak on reset failure in runtime resume

[Jiawen Liu]

sun4i_frontend_runtime_resume() can fail after enabling the bus, mod,
and ram clocks if reset_control_reset() returns an error. The function
previously returned without disabling those clocks, leaking them and
leaving the hardware in an inconsistent state.

Check the return value of each clk_prepare_enable() call and unwind the
clocks that were successfully enabled on any subsequent failure,
including reset failure.

Signed-off-by: jiawen <1298662399@xxxxxx>
---
diff --git a/drivers/gpu/drm/sun4i/sun4i_frontend.c b/drivers/gpu/drm/sun4i/sun4i_frontend.c
--- a/drivers/gpu/drm/sun4i/sun4i_frontend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_frontend.c
@@ -647,14 +647,22 @@
 
 	clk_set_rate(frontend->mod_clk, 300000000);
 
-	clk_prepare_enable(frontend->bus_clk);
-	clk_prepare_enable(frontend->mod_clk);
-	clk_prepare_enable(frontend->ram_clk);
+	ret = clk_prepare_enable(frontend->bus_clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(frontend->mod_clk);
+	if (ret)
+		goto err_disable_bus_clk;
+
+	ret = clk_prepare_enable(frontend->ram_clk);
+	if (ret)
+		goto err_disable_mod_clk;
 
 	ret = reset_control_reset(frontend->reset);
 	if (ret) {
 		dev_err(dev, "Couldn't reset our device\n");
-		return ret;
+		goto err_disable_ram_clk;
 	}
 
 	regmap_update_bits(frontend->regs, SUN4I_FRONTEND_EN_REG,
@@ -664,6 +672,14 @@
 	sun4i_frontend_scaler_init(frontend);
 
 	return 0;
+
+err_disable_ram_clk:
+	clk_disable_unprepare(frontend->ram_clk);
+err_disable_mod_clk:
+	clk_disable_unprepare(frontend->mod_clk);
+err_disable_bus_clk:
+	clk_disable_unprepare(frontend->bus_clk);
+	return ret;
 }
 
 static int sun4i_frontend_runtime_suspend(struct device *dev)