[PATCH 0/3] can: m_can: Add PM Runtime Support

[PATCH 0/3] can: m_can: Add PM Runtime Support

[Franklin S Cooper Jr]

Add PM runtime support to the MCAN driver. To support devices that don't use
PM runtime leave the original clk calls in the driver. Perhaps in the future
when it makes sense we can remove these non pm runtime clk calls.

Franklin S Cooper Jr (3):
  can: m_can: Make hclk optional
  can: m_can: Update documentation to indicate that hclk may be optional
  can: m_can: Add PM Runtime

 .../devicetree/bindings/net/can/m_can.txt          |  3 ++-
 drivers/net/can/m_can/m_can.c                      | 22 ++++++++++++++++++++--
 2 files changed, 22 insertions(+), 3 deletions(-)

-- 
2.10.0

[PATCH 1/3] can: m_can: Make hclk optional

[Franklin S Cooper Jr]

Hclk is the MCAN's interface clock. However, for OMAP based devices such as
DRA7 SoC family the interface clock is handled by hwmod. Therefore, this
interface clock is managed by hwmod driver via pm_runtime_get and
pm_runtime_put calls. Therefore, this interface clock isn't defined in DT
and thus the driver shouldn't fail if this clock isn't found.

Signed-off-by: Franklin S Cooper Jr <fcooper-l0cyMroinI0@public.gmane.org>
---
 drivers/net/can/m_can/m_can.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index f4947a7..7fe9145 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1568,8 +1568,13 @@ static int m_can_plat_probe(struct platform_device *pdev)
 	hclk = devm_clk_get(&pdev->dev, "hclk");
 	cclk = devm_clk_get(&pdev->dev, "cclk");
 
-	if (IS_ERR(hclk) || IS_ERR(cclk)) {
-		dev_err(&pdev->dev, "no clock found\n");
+	if (IS_ERR(hclk)) {
+		dev_warn(&pdev->dev, "can't find hclk\n");
+		hclk = 0;
+	}
+
+	if (IS_ERR(cclk)) {
+		dev_err(&pdev->dev, "cclk could not be found\n");
 		ret = -ENODEV;
 		goto failed_ret;
 	}
-- 
2.10.0

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Re: [PATCH 1/3] can: m_can: Make hclk optional

[Sergei Shtylyov]

Hello!

On 7/20/2017 2:09 AM, Franklin S Cooper Jr wrote:

> Hclk is the MCAN's interface clock. However, for OMAP based devices such as
> DRA7 SoC family the interface clock is handled by hwmod. Therefore, this
> interface clock is managed by hwmod driver via pm_runtime_get and
> pm_runtime_put calls. Therefore, this interface clock isn't defined in DT
> and thus the driver shouldn't fail if this clock isn't found.
> 
> Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
> ---
>   drivers/net/can/m_can/m_can.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index f4947a7..7fe9145 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
> @@ -1568,8 +1568,13 @@ static int m_can_plat_probe(struct platform_device *pdev)
>   	hclk = devm_clk_get(&pdev->dev, "hclk");
>   	cclk = devm_clk_get(&pdev->dev, "cclk");
>   
> -	if (IS_ERR(hclk) || IS_ERR(cclk)) {
> -		dev_err(&pdev->dev, "no clock found\n");
> +	if (IS_ERR(hclk)) {
> +		dev_warn(&pdev->dev, "can't find hclk\n");
> +		hclk = 0;

    s/0/NULL/.

[...]

MBR, Sergei

[PATCH 2/3] can: m_can: Update documentation to indicate that hclk may be optional

[Franklin S Cooper Jr]

Update the documentation to reflect that hclk is now an optional clock.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
---
 Documentation/devicetree/bindings/net/can/m_can.txt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/can/m_can.txt b/Documentation/devicetree/bindings/net/can/m_can.txt
index 9e33177..2a0fe5b 100644
--- a/Documentation/devicetree/bindings/net/can/m_can.txt
+++ b/Documentation/devicetree/bindings/net/can/m_can.txt
@@ -12,7 +12,8 @@ Required properties:
 - interrupt-names	: Should contain "int0" and "int1"
 - clocks		: Clocks used by controller, should be host clock
 			  and CAN clock.
-- clock-names		: Should contain "hclk" and "cclk"
+- clock-names		: Should contain "hclk" and "cclk". For some socs hclk
+			  may be optional.
 - pinctrl-<n>		: Pinctrl states as described in bindings/pinctrl/pinctrl-bindings.txt
 - pinctrl-names 	: Names corresponding to the numbered pinctrl states
 - bosch,mram-cfg	: Message RAM configuration data.
-- 
2.10.0

Re: [PATCH 2/3] can: m_can: Update documentation to indicate that hclk may be optional

[Rob Herring]

On Wed, Jul 19, 2017 at 06:09:25PM -0500, Franklin S Cooper Jr wrote:
> Update the documentation to reflect that hclk is now an optional clock.
> 
> Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
> ---
>  Documentation/devicetree/bindings/net/can/m_can.txt | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Acked-by: Rob Herring <robh@kernel.org>

[PATCH 3/3] can: m_can: Add PM Runtime

[Franklin S Cooper Jr]

Add support for PM Runtime which is the new way to handle managing clocks.
However, to avoid breaking SoCs not using PM_RUNTIME leave the old clk
management approach in place.

PM_RUNTIME is required by OMAP based devices to handle clock management.
Therefore, this allows future Texas Instruments SoCs that have the MCAN IP
to work with this driver.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
---
 drivers/net/can/m_can/m_can.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 7fe9145..eb45cd5 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -23,6 +23,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/iopoll.h>
 #include <linux/can/dev.h>
 
@@ -633,11 +634,15 @@ static int m_can_clk_start(struct m_can_priv *priv)
 	if (err)
 		clk_disable_unprepare(priv->hclk);
 
+	pm_runtime_get_sync(priv->device);
+
 	return err;
 }
 
 static void m_can_clk_stop(struct m_can_priv *priv)
 {
+	pm_runtime_put_sync(priv->device);
+
 	clk_disable_unprepare(priv->cclk);
 	clk_disable_unprepare(priv->hclk);
 }
@@ -1582,6 +1587,8 @@ static int m_can_plat_probe(struct platform_device *pdev)
 	/* Enable clocks. Necessary to read Core Release in order to determine
 	 * M_CAN version
 	 */
+	pm_runtime_enable(&pdev->dev);
+
 	ret = clk_prepare_enable(hclk);
 	if (ret)
 		goto disable_hclk_ret;
@@ -1626,6 +1633,8 @@ static int m_can_plat_probe(struct platform_device *pdev)
 	 */
 	tx_fifo_size = mram_config_vals[7];
 
+	pm_runtime_get_sync(&pdev->dev);
+
 	/* allocate the m_can device */
 	dev = alloc_m_can_dev(pdev, addr, tx_fifo_size);
 	if (!dev) {
@@ -1670,6 +1679,7 @@ static int m_can_plat_probe(struct platform_device *pdev)
 disable_hclk_ret:
 	clk_disable_unprepare(hclk);
 failed_ret:
+	pm_runtime_put_sync(&pdev->dev);
 	return ret;
 }
 
@@ -1726,6 +1736,9 @@ static int m_can_plat_remove(struct platform_device *pdev)
 	struct net_device *dev = platform_get_drvdata(pdev);
 
 	unregister_m_can_dev(dev);
+
+	pm_runtime_disable(&pdev->dev);
+
 	platform_set_drvdata(pdev, NULL);
 
 	free_m_can_dev(dev);
-- 
2.10.0