linux-kernel - [RESEND PATCH] amba: Allow pclk to be controlled by power domain

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Date:   Wed, 30 Jan 2019 18:01:41 -0800
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Russell King <linux@...linux.org.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Ulf Hansson <ulf.hansson@...aro.org>
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Subject: [RESEND PATCH] amba: Allow pclk to be controlled by power domain

On the Qualcomm SDM845 platform the apb_pclk is controlled as part of
the QDSS power/clock domain. Handle this by allowing amba to operate
without direct apb_pclk control, when a powerdomain is attached and no
clock is described.

Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---

Resending this separate from the series it was originally part of.

 drivers/amba/bus.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 41b706403ef7..3e13050c6d59 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -219,8 +219,13 @@ static int amba_get_enable_pclk(struct amba_device *pcdev)
 	int ret;
 
 	pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
-	if (IS_ERR(pcdev->pclk))
-		return PTR_ERR(pcdev->pclk);
+	if (IS_ERR(pcdev->pclk)) {
+		/* Continue with no clock specified, but pm_domain attached */
+		if (PTR_ERR(pcdev->pclk) == -ENOENT && pcdev->dev.pm_domain)
+			pcdev->pclk = NULL;
+		else
+			return PTR_ERR(pcdev->pclk);
+	}
 
 	ret = clk_prepare_enable(pcdev->pclk);
 	if (ret)
-- 
2.18.0