linux-kernel - [PATCH 07/18] dmaengine/amba-pl08x: Enable/Disable amba

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Date:	Fri, 29 Jul 2011 16:19:17 +0530
From:	Viresh Kumar <viresh.kumar@...com>
To:	<linus.walleij@...aro.org>
Cc:	<vinod.koul@...el.com>, <dan.j.williams@...el.com>,
	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux@....linux.org.uk>,
	<armando.visconti@...com>, <shiraz.hashim@...com>,
	<vipin.kumar@...com>, <rajeev-dlh.kumar@...com>,
	<deepak.sikri@...com>, <vipulkumar.samar@...com>,
	<amit.virdi@...com>, <viresh.kumar@...com>,
	<pratyush.anand@...com>, <bhupesh.sharma@...com>,
	<viresh.linux@...il.com>
Subject: [PATCH 07/18] dmaengine/amba-pl08x: Enable/Disable amba_pclk with channel requests

Amba devices have interface clocks attached as adev->pclk. This is the only
clock associated with DMAC and it can be disabled when DMAC is not in use. This
patch adds support to enable/disable this clk as and when channels are requested
and freed. Also it disables this clock at the end of probe.

Signed-off-by: Viresh Kumar <viresh.kumar@...com>
---
 drivers/dma/amba-pl08x.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 53d722e..f1a25cf 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -881,11 +881,19 @@ static void pl08x_free_txd_list(struct pl08x_driver_data *pl08x,
  */
 static int pl08x_alloc_chan_resources(struct dma_chan *chan)
 {
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	struct pl08x_driver_data *pl08x = plchan->host;
+
+	amba_pclk_enable(pl08x->adev);
 	return 0;
 }
 
 static void pl08x_free_chan_resources(struct dma_chan *chan)
 {
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	struct pl08x_driver_data *pl08x = plchan->host;
+
+	amba_pclk_disable(pl08x->adev);
 }
 
 /*
@@ -1993,6 +2001,8 @@ static int pl08x_probe(struct amba_device *adev, const struct amba_id *id)
 	dev_info(&pl08x->adev->dev, "DMA: PL%03x rev%u at 0x%08llx irq %d\n",
 		 amba_part(adev), amba_rev(adev),
 		 (unsigned long long)adev->res.start, adev->irq[0]);
+
+	amba_pclk_disable(adev);
 	return 0;
 
 out_no_slave_reg:
-- 
1.7.2.2

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