diff mbox

[5/9] clk: qcom: gcc-msm8960: add child devices support.

Message ID 55CBC14B.8000509@codeaurora.org (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Stephen Boyd Aug. 12, 2015, 9:57 p.m. UTC
On 08/12/2015 01:18 PM, Bjorn Andersson wrote:
> On Tue 11 Aug 15:49 PDT 2015, Stephen Boyd wrote:
>
>> On 07/08, Rajendra Nayak wrote:
>>> diff --git a/drivers/clk/qcom/gcc-msm8960.c b/drivers/clk/qcom/gcc-msm8960.c
>>> index eb6a4f9..2c80d03 100644
>>> --- a/drivers/clk/qcom/gcc-msm8960.c
>>> +++ b/drivers/clk/qcom/gcc-msm8960.c
>>> @@ -15,6 +15,7 @@
>>>   #include <linux/bitops.h>
>>>   #include <linux/err.h>
>>>   #include <linux/platform_device.h>
>>> +#include <linux/of_platform.h>
>>>   #include <linux/module.h>
>>>   #include <linux/of.h>
>>>   #include <linux/of_device.h>
>>> @@ -3520,7 +3521,8 @@ static int gcc_msm8960_probe(struct platform_device *pdev)
>>>   	if (IS_ERR(clk))
>>>   		return PTR_ERR(clk);
>>>   
>>> -	return qcom_cc_probe(pdev, match->data);
>>> +	qcom_cc_probe(pdev, match->data);
>>> +	return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
>> We just lost the error code from qcom_cc_probe()...
>>
>> Also, I don't like having a subnode in DT. Why can't we use the
>> same node as the GCC node and create a virtual child device here
>> for tsens? We can assign the same of_node that this platform
>> device has so that DT keeps working correctly.
>>
> Can't we make the gcc driver support being a child of a simple-mfd by
> having it attempting to acquire the regmap of the parent and falling
> back to creating its own mmio regmap?

So we would need to make a new device and driver for the simple-mfd 
parent? I'm confused about what you're suggesting and what benefit it 
has versus creating a child of the clock controller device.

Here's the patch I'm suggesting. The device name is probably wrong, but 
you get the idea.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
----8<----

Comments

Bjorn Andersson Aug. 13, 2015, 4:14 a.m. UTC | #1
On Wed 12 Aug 14:57 PDT 2015, Stephen Boyd wrote:

> On 08/12/2015 01:18 PM, Bjorn Andersson wrote:
> > On Tue 11 Aug 15:49 PDT 2015, Stephen Boyd wrote:
> >
> >> On 07/08, Rajendra Nayak wrote:
> >>> diff --git a/drivers/clk/qcom/gcc-msm8960.c b/drivers/clk/qcom/gcc-msm8960.c
> >>> index eb6a4f9..2c80d03 100644
> >>> --- a/drivers/clk/qcom/gcc-msm8960.c
> >>> +++ b/drivers/clk/qcom/gcc-msm8960.c
> >>> @@ -15,6 +15,7 @@
> >>>   #include <linux/bitops.h>
> >>>   #include <linux/err.h>
> >>>   #include <linux/platform_device.h>
> >>> +#include <linux/of_platform.h>
> >>>   #include <linux/module.h>
> >>>   #include <linux/of.h>
> >>>   #include <linux/of_device.h>
> >>> @@ -3520,7 +3521,8 @@ static int gcc_msm8960_probe(struct platform_device *pdev)
> >>>   	if (IS_ERR(clk))
> >>>   		return PTR_ERR(clk);
> >>>   
> >>> -	return qcom_cc_probe(pdev, match->data);
> >>> +	qcom_cc_probe(pdev, match->data);
> >>> +	return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
> >> We just lost the error code from qcom_cc_probe()...
> >>
> >> Also, I don't like having a subnode in DT. Why can't we use the
> >> same node as the GCC node and create a virtual child device here
> >> for tsens? We can assign the same of_node that this platform
> >> device has so that DT keeps working correctly.
> >>
> > Can't we make the gcc driver support being a child of a simple-mfd by
> > having it attempting to acquire the regmap of the parent and falling
> > back to creating its own mmio regmap?
> 
> So we would need to make a new device and driver for the simple-mfd 
> parent?

No that part is already in mainline, so my idea was that we add an early
return in qcom_cc_map() like:

	 struct device *dev = &pdev->dev;
+        struct regmap *map;
+
+        map = syscon_node_to_regmap(dev->parent->of_node);
+        if (!IS_ERR(map))
+                return map;

And then just update the dts to:

	gcc {
		compatible = "syscon", "simple-mfd";
		reg = <0x00900000 0x4000>;

		gcc: clock-controller {
			compatible = "qcom,gcc-apq8064";
			#clock-cells = <1>;
			#reset-cells = <1>;
		};
	};

But as I implemented this I realized that the syscon_node_to_regmap()
does not register the regmap as a devres of the parent, and as such it's
not caught by the regmap lookup in devm_clk_register_regmap().

So either one would need to make the syscon throw the regmap into devres
or make it possible to pass a regmap to devm_clk_register_regmap() for
this to work.

> I'm confused about what you're suggesting and what benefit it 
> has versus creating a child of the clock controller device.

The benefit would simply be that we're using the already existing
mechanism for handling multiple platform_drivers sharing a hw block.

> 
> Here's the patch I'm suggesting. The device name is probably wrong, but 
> you get the idea.

Looks very much like my take on it as well, I do however have concerns
that suddenly the node called "clock-controller" will have to come with
tsens related properties.

Are all the tsens-in-gcc blocks the same? Or do you intend to of_match
on the gcc compatible in the tsens driver?

Regards,
Bjorn
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Stephen Boyd Aug. 14, 2015, 12:46 a.m. UTC | #2
On 08/12, Bjorn Andersson wrote:
> On Wed 12 Aug 14:57 PDT 2015, Stephen Boyd wrote:
> 
> > Here's the patch I'm suggesting. The device name is probably wrong, but 
> > you get the idea.
> 
> Looks very much like my take on it as well, I do however have concerns
> that suddenly the node called "clock-controller" will have to come with
> tsens related properties.
> 
> Are all the tsens-in-gcc blocks the same?

Yes they're all the same, except some of them have more sensors
than others. It depends on what SoC the hardware is instantiated
in. They also messed up the software interface and had to add
discontinuous registers for the sensors because it was never
designed to have more than 4 sensors or something like that. But
even that sort of change can be handled by figuring out the
format of the sensor data in the qfprom.

> Or do you intend to of_match
> on the gcc compatible in the tsens driver?
> 

I hope we don't have to of_match in the tsens driver on gcc
compatible strings.
diff mbox

Patch

diff --git a/drivers/clk/qcom/gcc-msm8960.c b/drivers/clk/qcom/gcc-msm8960.c
index aa294b1bad34..802e9794f76e 100644
--- a/drivers/clk/qcom/gcc-msm8960.c
+++ b/drivers/clk/qcom/gcc-msm8960.c
@@ -3505,7 +3505,9 @@  static int gcc_msm8960_probe(struct platform_device *pdev)
  {
  	struct clk *clk;
  	struct device *dev = &pdev->dev;
+	struct platform_device *tsens;
  	const struct of_device_id *match;
+	int ret;
  
  	match = of_match_device(gcc_msm8960_match_table, &pdev->dev);
  	if (!match)
@@ -3520,7 +3522,30 @@  static int gcc_msm8960_probe(struct platform_device *pdev)
  	if (IS_ERR(clk))
  		return PTR_ERR(clk);
  
-	return qcom_cc_probe(pdev, match->data);
+	ret = qcom_cc_probe(pdev, match->data);
+	if (ret)
+		return ret;
+
+	tsens = platform_device_alloc("tsens", -1);
+	if (!tsens) {
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	tsens->dev.parent = &pdev->dev;
+	tsens->dev.of_node = pdev->dev.of_node;
+	ret = platform_device_add(tsens);
+	if (ret)
+		goto err_add;
+
+	return 0;
+
+err_add:
+	platform_device_put(tsens);
+err_alloc:
+	qcom_cc_remove(pdev);
+
+	return ret;
  }
  
  static int gcc_msm8960_remove(struct platform_device *pdev)