linux-kernel - [PATCH] dmaengine: qcom: bam_dma: make channels/EEs optional in DT with clock

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Message-Id: <20230518-bamclk-dt-v1-1-82f738c897d9@gerhold.net>
Date:   Thu, 18 May 2023 11:26:00 +0200
From:   Stephan Gerhold <stephan@...hold.net>
To:     Vinod Koul <vkoul@...nel.org>
Cc:     Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        linux-arm-msm@...r.kernel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, Stephan Gerhold <stephan@...hold.net>
Subject: [PATCH] dmaengine: qcom: bam_dma: make channels/EEs optional in DT
 with clock

If we have a BAM clock in the DT we are able to turn on the BAM
controller while probing, so there is no need to read "num-channels"
and "qcom,num-ees" from the DT. It can be read more accurately directly
from the identification registers of the BAM.

This simplifies setting up typical controlled-remotely BAM DMAs in the
DT that can be turned on via a clock (e.g. the BLSP DMA).

Signed-off-by: Stephan Gerhold <stephan@...hold.net>
---
 drivers/dma/qcom/bam_dma.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 1e47d27e1f81..4c3eb972039d 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -1272,7 +1272,15 @@ static int bam_dma_probe(struct platform_device *pdev)
 	bdev->powered_remotely = of_property_read_bool(pdev->dev.of_node,
 						"qcom,powered-remotely");
 
-	if (bdev->controlled_remotely || bdev->powered_remotely) {
+	if (bdev->controlled_remotely || bdev->powered_remotely)
+		bdev->bamclk = devm_clk_get_optional(bdev->dev, "bam_clk");
+	else
+		bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
+
+	if (IS_ERR(bdev->bamclk))
+		return PTR_ERR(bdev->bamclk);
+
+	if (!bdev->bamclk) {
 		ret = of_property_read_u32(pdev->dev.of_node, "num-channels",
 					   &bdev->num_channels);
 		if (ret)
@@ -1284,14 +1292,6 @@ static int bam_dma_probe(struct platform_device *pdev)
 			dev_err(bdev->dev, "num-ees unspecified in dt\n");
 	}
 
-	if (bdev->controlled_remotely || bdev->powered_remotely)
-		bdev->bamclk = devm_clk_get_optional(bdev->dev, "bam_clk");
-	else
-		bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
-
-	if (IS_ERR(bdev->bamclk))
-		return PTR_ERR(bdev->bamclk);
-
 	ret = clk_prepare_enable(bdev->bamclk);
 	if (ret) {
 		dev_err(bdev->dev, "failed to prepare/enable clock\n");

---
base-commit: 1c677f238f92ba0a329b7c13220f38b396872806
change-id: 20230518-bamclk-dt-d44bae47b337

Best regards,
-- 
Stephan Gerhold <stephan@...hold.net>