On Thu, 2016-04-21 at 09:32:44 -0700, Appana Durga Kedareswara Rao wrote: > Hi Soren, > > > -----Original Message----- > > From: Sören Brinkmann [mailto:soren.brinkmann@xxxxxxxxxx] > > Sent: Thursday, April 21, 2016 9:52 PM > > To: Appana Durga Kedareswara Rao <appanad@xxxxxxxxxx> > > Cc: robh+dt@xxxxxxxxxx; pawel.moll@xxxxxxx; mark.rutland@xxxxxxx; > > ijc+devicetree@xxxxxxxxxxxxxx; galak@xxxxxxxxxxxxxx; Michal Simek > > <michals@xxxxxxxxxx>; vinod.koul@xxxxxxxxx; dan.j.williams@xxxxxxxxx; > > Appana Durga Kedareswara Rao <appanad@xxxxxxxxxx>; > > moritz.fischer@xxxxxxxxx; laurent.pinchart@xxxxxxxxxxxxxxxx; > > luis@xxxxxxxxxxxxxxxxx; Anirudha Sarangi <anirudh@xxxxxxxxxx>; Punnaiah > > Choudary Kalluri <punnaia@xxxxxxxxxx>; Shubhrajyoti Datta > > <shubhraj@xxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx; linux-arm- > > kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > dmaengine@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH v3 3/3] dmaengine: vdma: Add clock support > > > > On Thu, 2016-04-21 at 16:08:38 +0530, Kedareswara rao Appana wrote: [...] > > > @@ -1757,6 +1767,200 @@ static void xilinx_dma_chan_remove(struct > > xilinx_dma_chan *chan) > > > list_del(&chan->common.device_node); > > > } > > > > > > +static int axidma_clk_init(struct platform_device *pdev, struct clk **axi_clk, > > > + struct clk **tx_clk, struct clk **rx_clk, > > > + struct clk **sg_clk, struct clk **tmp_clk) { > > > + int err; > > > + > > > + *tmp_clk = NULL; > > > + > > > + *axi_clk = devm_clk_get(&pdev->dev, "s_axi_lite_aclk"); > > > + if (IS_ERR(*axi_clk)) { > > > + err = PTR_ERR(*axi_clk); > > > + dev_err(&pdev->dev, "failed to get axi_aclk (%u)\n", err); > > > + return err; > > > + } > > > + > > > + *tx_clk = devm_clk_get(&pdev->dev, "m_axi_mm2s_aclk"); > > > + if (IS_ERR(*tx_clk)) > > > + *tx_clk = NULL; > > > + > > > + *rx_clk = devm_clk_get(&pdev->dev, "m_axi_s2mm_aclk"); > > > + if (IS_ERR(*rx_clk)) > > > + *rx_clk = NULL; > > > + > > > + *sg_clk = devm_clk_get(&pdev->dev, "m_axi_sg_aclk"); > > > + if (IS_ERR(*sg_clk)) > > > + *sg_clk = NULL; > > > + > > > + > > > + err = clk_prepare_enable(*axi_clk); > > > > Should this be called if you know that the pointer might be NULL? > > It is a mandatory clock and if this clk is not there in DT I am already returning error... > I didn't get your question could you please elaborate??? But for all the optional clocks. They could all be NULL and you're calling clk_prepare_enable with a NULL pointer. That function is nice enough to do a NULL check for you, but I wonder whether these calls should happen at all when you already know that the pointer is not a valid clock. Sören -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
