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Subject[PATCH 2/3] dmaengine: tegra210-adma: use devm_clk_*() helpers
Date
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 b26256f..123fc6d 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;
@@ -692,13 +694,11 @@ 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);

@@ -775,8 +775,6 @@ 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;
}
@@ -793,22 +791,15 @@ 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
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