[PATCH v7 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[PATCH v7 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Bjorn Andersson]

Add binding documentation for the Qualcomm Hardware Mutex.

Reviewed-by: Andy Gross <agross@codeaurora.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
---

Changes since v6:
- Corrected indentation error in example

Changes since v5:
- Extracted the dt binding documentation into a separate patch
- Moved the driver to consume a syscon
- Dropped previously suggested generic hwlock dt bindings

 .../devicetree/bindings/hwlock/qcom-hwspinlock.txt | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt

diff --git a/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
new file mode 100644
index 0000000..4f8ebd9
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
@@ -0,0 +1,39 @@
+Qualcomm Hardware Mutex Block:
+
+The hardware block provides mutexes utilized between different processors on
+the SoC as part of the communication protocol used by these processors.
+
+- compatible:
+	Usage: required
+	Value type: <string>
+	Definition: must be one of:
+		    "qcom,sfpb-mutex",
+		    "qcom,tcsr-mutex"
+
+- syscon:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: one cell containing:
+		    syscon phandle
+		    offset of the hwmutex block within the syscon
+		    stride of the hwmutex registers
+
+- #hwlock-cells:
+	Usage: required
+	Value type: <u32>
+	Definition: must be 1, the specified cell represent the lock id
+		    (hwlock standard property, see hwlock.txt)
+
+Example:
+
+	tcsr: syscon@1a400000 {
+		compatible = "qcom,tcsr-msm8974", "syscon";
+		reg = <0xfd484000 0x2000>;
+	};
+
+	hwlock@fd484000 {
+		compatible = "qcom,tcsr-mutex";
+		syscon = <&tcsr 0 0x80>;
+
+		#hwlock-cells = <1>;
+	};
-- 
1.8.2.2

Re: [PATCH v7 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Andy Gross]

On Thu, Mar 19, 2015 at 06:48:10PM -0700, Bjorn Andersson wrote:

<snip>

> +Example:
> +
> +	tcsr: syscon@1a400000 {

typo here, syscon@fd484000.  And this syscon is specifically for the tcsr mutex
reg area.

> +		compatible = "qcom,tcsr-msm8974", "syscon";
> +		reg = <0xfd484000 0x2000>;

<snip>

-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v7 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Bjorn Andersson]

On Fri 20 Mar 13:29 PDT 2015, Andy Gross wrote:

> On Thu, Mar 19, 2015 at 06:48:10PM -0700, Bjorn Andersson wrote:
> 
> <snip>
> 
> > +Example:
> > +
> > +	tcsr: syscon@1a400000 {
> 
> typo here, syscon@fd484000.  And this syscon is specifically for the tcsr mutex
> reg area.
> 

You're right, I didn't read the documentation good enough; let's name it
tcsr-mutex and as this is not the main tcsr region we should fall back
to just having syscon as compatible.

But there's still a bunch of other registers in the tcsr-mutex range -
that probably will be consumed by various drivers, so it still makes
sense to have a syscon there.

Sorry about the address, will update that as well.

> > +		compatible = "qcom,tcsr-msm8974", "syscon";
> > +		reg = <0xfd484000 0x2000>;
> 

Regards,
Bjorn

Re: [PATCH v7 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Andy Gross]

On Fri, Mar 20, 2015 at 01:49:12PM -0700, Bjorn Andersson wrote:
> On Fri 20 Mar 13:29 PDT 2015, Andy Gross wrote:
> 
> > On Thu, Mar 19, 2015 at 06:48:10PM -0700, Bjorn Andersson wrote:
> > 
> > <snip>
> > 
> > > +Example:
> > > +
> > > +	tcsr: syscon@1a400000 {
> > 
> > typo here, syscon@fd484000.  And this syscon is specifically for the tcsr mutex
> > reg area.
> > 
> 
> You're right, I didn't read the documentation good enough; let's name it
> tcsr-mutex and as this is not the main tcsr region we should fall back
> to just having syscon as compatible.

Agreed.  A generic syscon will work until we need to support the other registers
in that block.

> But there's still a bunch of other registers in the tcsr-mutex range -
> that probably will be consumed by various drivers, so it still makes
> sense to have a syscon there.

Agreed.

-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project