[PATCH v3 4/4] hwrng: meson: add clock handling to driver
Heiner Kallweit
hkallweit1 at gmail.com
Tue Feb 21 23:02:31 PST 2017
Add handling of RNG0 clock to the driver.
Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
---
v2:
- consider that clock is optional
- use managed call to clk_disable_unprepare to ensure that
cleaning up is done in the right order if driver is removed
v3:
- no changes
---
drivers/char/hw_random/meson-rng.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
index 119d6984..2e23be80 100644
--- a/drivers/char/hw_random/meson-rng.c
+++ b/drivers/char/hw_random/meson-rng.c
@@ -62,6 +62,7 @@
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/of.h>
+#include <linux/clk.h>
#define RNG_DATA 0x00
@@ -69,6 +70,7 @@ struct meson_rng_data {
void __iomem *base;
struct platform_device *pdev;
struct hwrng rng;
+ struct clk *core_clk;
};
static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -81,11 +83,17 @@ static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
return sizeof(u32);
}
+static void meson_rng_clk_disable(void *data)
+{
+ clk_disable_unprepare(data);
+}
+
static int meson_rng_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct meson_rng_data *data;
struct resource *res;
+ int ret;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
@@ -98,6 +106,20 @@ static int meson_rng_probe(struct platform_device *pdev)
if (IS_ERR(data->base))
return PTR_ERR(data->base);
+ data->core_clk = devm_clk_get(dev, "core");
+ if (IS_ERR(data->core_clk))
+ data->core_clk = NULL;
+
+ if (data->core_clk) {
+ ret = clk_prepare_enable(data->core_clk);
+ if (ret)
+ return ret;
+ ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
+ data->core_clk);
+ if (ret)
+ return ret;
+ }
+
data->rng.name = pdev->name;
data->rng.read = meson_rng_read;
--
2.11.1
More information about the linux-amlogic
mailing list