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From:   Sameer Pujar <spujar@nvidia.com>
To:     <dan.j.williams@intel.com>, <vkoul@kernel.org>
CC:     <treding@nvidia.com>, <jonathanh@nvidia.com>,
        <dmaengine@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, Sameer Pujar <spujar@nvidia.com>
Subject: [PATCH] dmaengine: tegra210-adma: use devm_clk_*() helpers
Date:   Tue, 12 Mar 2019 20:05:52 +0530
Message-ID: <1552401352-30043-1-git-send-email-spujar@nvidia.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Usage of pm_clk_*() results in non-zero prepare_count for clocks and hence
module clocks remain ON always. This is not desired as it will leak power
unncessarily. This patch replaces pm_clk_*() with devm_clk_*() interface.
This helps to keep refcounts balanced when device is not in use and runtime
PM callbacks help to enable or disable clocks. System suspend/resume calls
can use pm_runtime_force_suspend/resume.

Suggested-by: Mohan Kumar D <mkumard@nvidia.com>
Reviewed-by: Jonathan Hunter <jonathanh@nvidia.com>
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
---
 drivers/dma/tegra210-adma.c | 37 ++++++++++++++-----------------------
 1 file changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
index 5ec0dd9..be29171 100644
--- a/drivers/dma/tegra210-adma.c
+++ b/drivers/dma/tegra210-adma.c
@@ -22,7 +22,6 @@
 #include <linux/of_device.h>
 #include <linux/of_dma.h>
 #include <linux/of_irq.h>
-#include <linux/pm_clock.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
@@ -141,6 +140,7 @@ struct tegra_adma {
 	struct dma_device		dma_dev;
 	struct device			*dev;
 	void __iomem			*base_addr;
+	struct clk			*ahub_clk;
 	unsigned int			nr_channels;
 	unsigned long			rx_requests_reserved;
 	unsigned long			tx_requests_reserved;
@@ -637,8 +637,9 @@ static int tegra_adma_runtime_suspend(struct device *dev)
 	struct tegra_adma *tdma = dev_get_drvdata(dev);
 
 	tdma->global_cmd = tdma_read(tdma, ADMA_GLOBAL_CMD);
+	clk_disable_unprepare(tdma->ahub_clk);
 
-	return pm_clk_suspend(dev);
+	return 0;
 }
 
 static int tegra_adma_runtime_resume(struct device *dev)
@@ -646,10 +647,11 @@ static int tegra_adma_runtime_resume(struct device *dev)
 	struct tegra_adma *tdma = dev_get_drvdata(dev);
 	int ret;
 
-	ret = pm_clk_resume(dev);
-	if (ret)
+	ret = clk_prepare_enable(tdma->ahub_clk);
+	if (ret) {
+		dev_err(dev, "ahub clk_enable failed: %d\n", ret);
 		return ret;
-
+	}
 	tdma_write(tdma, ADMA_GLOBAL_CMD, tdma->global_cmd);
 
 	return 0;
@@ -693,13 +695,11 @@ static int tegra_adma_probe(struct platform_device *pdev)
 	if (IS_ERR(tdma->base_addr))
 		return PTR_ERR(tdma->base_addr);
 
-	ret = pm_clk_create(&pdev->dev);
-	if (ret)
-		return ret;
-
-	ret = of_pm_clk_add_clk(&pdev->dev, "d_audio");
-	if (ret)
-		goto clk_destroy;
+	tdma->ahub_clk = devm_clk_get(&pdev->dev, "d_audio");
+	if (IS_ERR(tdma->ahub_clk)) {
+		dev_err(&pdev->dev, "Error: Missing ahub controller clock\n");
+		return PTR_ERR(tdma->ahub_clk);
+	}
 
 	pm_runtime_enable(&pdev->dev);
 
@@ -776,8 +776,6 @@ static int tegra_adma_probe(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 rpm_disable:
 	pm_runtime_disable(&pdev->dev);
-clk_destroy:
-	pm_clk_destroy(&pdev->dev);
 
 	return ret;
 }
@@ -794,22 +792,15 @@ static int tegra_adma_remove(struct platform_device *pdev)
 
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-	pm_clk_destroy(&pdev->dev);
 
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int tegra_adma_pm_suspend(struct device *dev)
-{
-	return pm_runtime_suspended(dev) == false;
-}
-#endif
-
 static const struct dev_pm_ops tegra_adma_dev_pm_ops = {
 	SET_RUNTIME_PM_OPS(tegra_adma_runtime_suspend,
 			   tegra_adma_runtime_resume, NULL)
-	SET_SYSTEM_SLEEP_PM_OPS(tegra_adma_pm_suspend, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
 };
 
 static struct platform_driver tegra_admac_driver = {
-- 
2.7.4