dma: tegra: enable/disable dma clock

Enable the DMA clock when allocating channel and
disable clock when freeing channels.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index d52dbc6c54ab..24acd711e032 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -1119,15 +1119,21 @@ struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
 static int tegra_dma_alloc_chan_resources(struct dma_chan *dc)
 {
         struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+        struct tegra_dma *tdma = tdc->tdma;
+        int ret;
 
         dma_cookie_init(&tdc->dma_chan);
         tdc->config_init = false;
-        return 0;
+        ret = clk_prepare_enable(tdma->dma_clk);
+        if (ret < 0)
+                dev_err(tdc2dev(tdc), "clk_prepare_enable failed: %d\n", ret);
+        return ret;
 }
 
 static void tegra_dma_free_chan_resources(struct dma_chan *dc)
 {
         struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+        struct tegra_dma *tdma = tdc->tdma;
 
         struct tegra_dma_desc *dma_desc;
         struct tegra_dma_sg_req *sg_req;
@@ -1163,6 +1169,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
                 list_del(&sg_req->node);
                 kfree(sg_req);
         }
+        clk_disable_unprepare(tdma->dma_clk);
 }
 
 /* Tegra20 specific DMA controller information */
@@ -1255,6 +1262,13 @@ static int __devinit tegra_dma_probe(struct platform_device *pdev)
                 }
         }
 
+        /* Enable clock before accessing registers */
+        ret = clk_prepare_enable(tdma->dma_clk);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "clk_prepare_enable failed: %d\n", ret);
+                goto err_pm_disable;
+        }
+
         /* Reset DMA controller */
         tegra_periph_reset_assert(tdma->dma_clk);
         udelay(2);
@@ -1265,6 +1279,8 @@ static int __devinit tegra_dma_probe(struct platform_device *pdev)
         tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0);
         tdma_write(tdma, TEGRA_APBDMA_IRQ_MASK_SET, 0xFFFFFFFFul);
 
+        clk_disable_unprepare(tdma->dma_clk);
+
         INIT_LIST_HEAD(&tdma->dma_dev.channels);
         for (i = 0; i < cdata->nr_channels; i++) {
                 struct tegra_dma_channel *tdc = &tdma->channels[i];