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hwrng: mtk - add runtime PM support 

Add runtime PM support.  There will be the benefit on SoCs where the
clock to the RNG used can be shutdown.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Sean Wang 2017-06-12 23:56:55 +08:00 committed by Herbert Xu
parent 34194913ea
commit 81d2b34508
1 changed files with 42 additions and 0 deletions
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42
drivers/char/hw_random/mtk-rng.c
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@ -25,6 +25,10 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
/* Runtime PM autosuspend timeout: */
#define RNG_AUTOSUSPEND_TIMEOUT 100
#define USEC_POLL 2
#define TIMEOUT_POLL 20
@ -90,6 +94,8 @@ static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
struct mtk_rng *priv = to_mtk_rng(rng);
int retval = 0;
pm_runtime_get_sync((struct device *)priv->rng.priv);
while (max >= sizeof(u32)) {
if (!mtk_rng_wait_ready(rng, wait))
break;
@ -100,6 +106,9 @@ static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
max -= sizeof(u32);
}
pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);
return retval || !wait ? retval : -EIO;
}
@ -120,9 +129,12 @@ static int mtk_rng_probe(struct platform_device *pdev)
return -ENOMEM;
priv->rng.name = pdev->name;
#ifndef CONFIG_PM
priv->rng.init = mtk_rng_init;
priv->rng.cleanup = mtk_rng_cleanup;
#endif
priv->rng.read = mtk_rng_read;
priv->rng.priv = (unsigned long)&pdev->dev;
priv->clk = devm_clk_get(&pdev->dev, "rng");
if (IS_ERR(priv->clk)) {
@ -142,11 +154,40 @@ static int mtk_rng_probe(struct platform_device *pdev)
return ret;
}
dev_set_drvdata(&pdev->dev, priv);
pm_runtime_set_autosuspend_delay(&pdev->dev, RNG_AUTOSUSPEND_TIMEOUT);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_enable(&pdev->dev);
dev_info(&pdev->dev, "registered RNG driver\n");
return 0;
}
#ifdef CONFIG_PM
static int mtk_rng_runtime_suspend(struct device *dev)
{
struct mtk_rng *priv = dev_get_drvdata(dev);
mtk_rng_cleanup(&priv->rng);
return 0;
}
static int mtk_rng_runtime_resume(struct device *dev)
{
struct mtk_rng *priv = dev_get_drvdata(dev);
return mtk_rng_init(&priv->rng);
}
static UNIVERSAL_DEV_PM_OPS(mtk_rng_pm_ops, mtk_rng_runtime_suspend,
mtk_rng_runtime_resume, NULL);
#define MTK_RNG_PM_OPS (&mtk_rng_pm_ops)
#else /* CONFIG_PM */
#define MTK_RNG_PM_OPS NULL
#endif /* CONFIG_PM */
static const struct of_device_id mtk_rng_match[] = {
{ .compatible = "mediatek,mt7623-rng" },
{},
@ -157,6 +198,7 @@ static struct platform_driver mtk_rng_driver = {
.probe = mtk_rng_probe,
.driver = {
.name = MTK_RNG_DEV,
.pm = MTK_RNG_PM_OPS,
.of_match_table = mtk_rng_match,
},
};