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Subject[PATCH 07/12] hwrng: bcm2835-rng: Manage an optional clock
Date
One of the last steps before bcm63xx-rng can be eliminated is to manage
a clock during hwrng::init and hwrng::cleanup, so fetch it in the probe
function, and manage it during these two steps when valid.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
drivers/char/hw_random/bcm2835-rng.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
index ed20e0b6b7ae..35928efb52e7 100644
--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -15,6 +15,7 @@
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
+#include <linux/clk.h>

#define RNG_CTRL 0x0
#define RNG_STATUS 0x4
@@ -33,6 +34,7 @@ struct bcm2835_rng_priv {
struct hwrng rng;
void __iomem *base;
bool mask_interrupts;
+ struct clk *clk;
};

static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng)
@@ -67,6 +69,11 @@ static int bcm2835_rng_init(struct hwrng *rng)
{
struct bcm2835_rng_priv *priv = to_rng_priv(rng);
u32 val;
+ int ret;
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return ret;

if (priv->mask_interrupts) {
/* mask the interrupt */
@@ -88,6 +95,8 @@ static void bcm2835_rng_cleanup(struct hwrng *rng)

/* disable rng hardware */
__raw_writel(0, priv->base + RNG_CTRL);
+
+ clk_disable_unprepare(priv->clk);
}

struct bcm2835_rng_of_data {
@@ -130,6 +139,11 @@ static int bcm2835_rng_probe(struct platform_device *pdev)
return PTR_ERR(priv->base);
}

+ /* Clock is optional on most platforms */
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk))
+ priv->clk = NULL;
+
priv->rng.name = "bcm2835-rng";
priv->rng.init = bcm2835_rng_init;
priv->rng.read = bcm2835_rng_read;
--
2.9.3
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