[PATCH 0/2] hwrng: omap: Fix clock resource for Armada 7K/8K

[PATCH 0/2] hwrng: omap: Fix clock resource for Armada 7K/8K

[Gregory CLEMENT]

Hi,

This short series fixes the way the clocks are used for the SafeXcel
IP-76 controller embedded in the Marvell Armada 7K/8K SoCs. On these
SoCs a second one is needed in order to clock the registers. It was
not noticed until now because we relied on the bootloader and also
because the clock driver was wrong.

Thanks to this fix, it would be possible to fix the clock driver
without introducing a regression.

The first patch is just a small cleanup found when I wrote the main
patch.

Gregory CLEMENT (2):
  hwrng: omap - Remove useless test before clk_disable_unprepare
  hwrng: omap - Fix clock resource by adding a register clock

 Documentation/devicetree/bindings/rng/omap_rng.txt |  7 ++++++-
 drivers/char/hw_random/omap-rng.c                  | 22 ++++++++++++++++++----
 2 files changed, 24 insertions(+), 5 deletions(-)

-- 
2.16.1

[PATCH 1/2] hwrng: omap - Remove useless test before clk_disable_unprepare

[Gregory CLEMENT]

clk_disable_unprepare() already checks that the clock pointer is valid.
No need to test it before calling it.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 drivers/char/hw_random/omap-rng.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c
index 74d11ae6abe9..159d4a1347b8 100644
--- a/drivers/char/hw_random/omap-rng.c
+++ b/drivers/char/hw_random/omap-rng.c
@@ -499,8 +499,7 @@ static int omap_rng_probe(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
-	if (!IS_ERR(priv->clk))
-		clk_disable_unprepare(priv->clk);
+	clk_disable_unprepare(priv->clk);
 err_ioremap:
 	dev_err(dev, "initialization failed.\n");
 	return ret;
@@ -517,8 +516,7 @@ static int omap_rng_remove(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
-	if (!IS_ERR(priv->clk))
-		clk_disable_unprepare(priv->clk);
+	clk_disable_unprepare(priv->clk);
 
 	return 0;
 }
-- 
2.16.1

[PATCH 2/2] hwrng: omap - Fix clock resource by adding a register clock

[Gregory CLEMENT]

On Armada 7K/8K we need to explicitly enable the register clock. This
clock is optional because not all the SoCs using this IP need it but at
least for Armada 7K/8K it is actually mandatory.

The binding documentation is updating accordingly.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 Documentation/devicetree/bindings/rng/omap_rng.txt |  7 ++++++-
 drivers/char/hw_random/omap-rng.c                  | 16 ++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/rng/omap_rng.txt b/Documentation/devicetree/bindings/rng/omap_rng.txt
index 9cf7876ab434..ea434ce50f36 100644
--- a/Documentation/devicetree/bindings/rng/omap_rng.txt
+++ b/Documentation/devicetree/bindings/rng/omap_rng.txt
@@ -13,7 +13,12 @@ Required properties:
 - interrupts : the interrupt number for the RNG module.
 		Used for "ti,omap4-rng" and "inside-secure,safexcel-eip76"
 - clocks: the trng clock source. Only mandatory for the
-  "inside-secure,safexcel-eip76" compatible.
+  "inside-secure,safexcel-eip76" compatible, the second clock is
+  needed for the Armada 7K/8K SoCs
+- clock-names: mandatory if there is a second clock, in this case the
+  name must be "core" for the first clock and "reg" for the second
+  one
+
 
 Example:
 /* AM335x */
diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c
index 159d4a1347b8..b65ff6962899 100644
--- a/drivers/char/hw_random/omap-rng.c
+++ b/drivers/char/hw_random/omap-rng.c
@@ -150,6 +150,7 @@ struct omap_rng_dev {
 	const struct omap_rng_pdata	*pdata;
 	struct hwrng rng;
 	struct clk 			*clk;
+	struct clk			*clk_reg;
 };
 
 static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg)
@@ -480,6 +481,19 @@ static int omap_rng_probe(struct platform_device *pdev)
 		}
 	}
 
+	priv->clk_reg = devm_clk_get(&pdev->dev, "reg");
+	if (IS_ERR(priv->clk_reg) && PTR_ERR(priv->clk_reg) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+	if (!IS_ERR(priv->clk_reg)) {
+		ret = clk_prepare_enable(priv->clk_reg);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Unable to enable the register clk: %d\n",
+				ret);
+			goto err_register;
+		}
+	}
+
 	ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) :
 				get_omap_rng_device_details(priv);
 	if (ret)
@@ -499,6 +513,7 @@ static int omap_rng_probe(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
+	clk_disable_unprepare(priv->clk_reg);
 	clk_disable_unprepare(priv->clk);
 err_ioremap:
 	dev_err(dev, "initialization failed.\n");
@@ -517,6 +532,7 @@ static int omap_rng_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 
 	clk_disable_unprepare(priv->clk);
+	clk_disable_unprepare(priv->clk_reg);
 
 	return 0;
 }
-- 
2.16.1

Re: [PATCH 0/2] hwrng: omap: Fix clock resource for Armada 7K/8K

[Herbert Xu]

On Wed, Feb 28, 2018 at 03:27:21PM +0100, Gregory CLEMENT wrote:
> Hi,
> 
> This short series fixes the way the clocks are used for the SafeXcel
> IP-76 controller embedded in the Marvell Armada 7K/8K SoCs. On these
> SoCs a second one is needed in order to clock the registers. It was
> not noticed until now because we relied on the bootloader and also
> because the clock driver was wrong.
> 
> Thanks to this fix, it would be possible to fix the clock driver
> without introducing a regression.
> 
> The first patch is just a small cleanup found when I wrote the main
> patch.
> 
> Gregory CLEMENT (2):
>   hwrng: omap - Remove useless test before clk_disable_unprepare
>   hwrng: omap - Fix clock resource by adding a register clock
> 
>  Documentation/devicetree/bindings/rng/omap_rng.txt |  7 ++++++-
>  drivers/char/hw_random/omap-rng.c                  | 22 ++++++++++++++++++----
>  2 files changed, 24 insertions(+), 5 deletions(-)

All applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt