dmaengine: at_xdmac: disable/enable clock directly on suspend/resume

Runtime PM APIs for at_xdmac just plays with clk_enable()/clk_disable()
letting aside the clk_prepare()/clk_unprepare() that needs to be
executed as the clock is also prepared on probe. Thus instead of using
runtime PM force suspend/resume APIs use
clk_disable_unprepare() + pm_runtime_put_noidle() on suspend and
clk_prepare_enable() + pm_runtime_get_noresume() on resume. This
approach as been chosen instead of using runtime PM force suspend/resume
with clk_unprepare()/clk_prepare() as it looks simpler and the final
code is better.

While at it added the missing pm_runtime_mark_last_busy() on suspend before
decrementing the reference counter.

Fixes: 650b0e99 ("dmaengine: at_xdmac: add runtime pm support")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230214151827.1050280-2-claudiu.beznea@microchip.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/at_xdmac.c

@@ -2130,7 +2130,11 @@ static int __maybe_unused atmel_xdmac_suspend(struct device *dev)
 	atxdmac->save_gim = at_xdmac_read(atxdmac, AT_XDMAC_GIM);
 
 	at_xdmac_off(atxdmac);
-	return pm_runtime_force_suspend(atxdmac->dev);
+	pm_runtime_mark_last_busy(atxdmac->dev);
+	pm_runtime_put_noidle(atxdmac->dev);
+	clk_disable_unprepare(atxdmac->clk);
+
+	return 0;
 }
 
 static int __maybe_unused atmel_xdmac_resume(struct device *dev)
@@ -2142,10 +2146,12 @@ static int __maybe_unused atmel_xdmac_resume(struct device *dev)
 	int			i;
 	int ret;
 
-	ret = pm_runtime_force_resume(atxdmac->dev);
-	if (ret < 0)
+	ret = clk_prepare_enable(atxdmac->clk);
+	if (ret)
 		return ret;
 
+	pm_runtime_get_noresume(atxdmac->dev);
+
 	at_xdmac_axi_config(pdev);
 
 	/* Clear pending interrupts. */