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

[Bjorn Andersson <bjorn.andersson@linaro.org>]

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@linaro.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