Rob,

Would you mind casting an eye on this please?

On Wed, 23 Nov 2016, Benjamin Gaignard wrote:

2016-11-23 10:21 GMT+01:00 Lee Jones [off-list ref]:

quoted

On Wed, 23 Nov 2016, Benjamin Gaignard wrote:

quoted

2016-11-22 17:52 GMT+01:00 Lee Jones [off-list ref]:

quoted

On Tue, 22 Nov 2016, Benjamin Gaignard wrote:

quoted

Add bindings information for stm32 timer MFD

Signed-off-by: Benjamin Gaignard <redacted>
---
 .../devicetree/bindings/mfd/stm32-timer.txt        | 53 ++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timer.txt

diff --git a/Documentation/devicetree/bindings/mfd/stm32-timer.txt b/Documentation/devicetree/bindings/mfd/stm32-timer.txt
new file mode 100644
index 0000000..3cefce1
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/stm32-timer.txt

@@ -0,0 +1,53 @@
+STM32 multifunctions timer driver

"STM32 Multi-Function Timer/PWM device bindings"

Doesn't this shared device have a better name?

In SoC documentation those hardware blocks are named "advanced-control
timers", "general purpose timers" or "basic timers"
"stm32-timer" name is already used for clock source driver, that why I
have prefix it with mfd

MFD is a Linuxisum and has no place in hardware description.

Please used one of the names you mentioned above.

I will go for "st,stm32-advanced-timer"

quoted

Hopefully the one that best fits.

quoted

quoted

quoted

+stm32 timer MFD allow to handle at the same time pwm and IIO timer devices

No need for this sentence.

OK

quoted

quoted

+Required parameters:
+- compatible: must be one of the follow value:
+     "st,stm32-mfd-timer1"
+     "st,stm32-mfd-timer2"
+     "st,stm32-mfd-timer3"
+     "st,stm32-mfd-timer4"
+     "st,stm32-mfd-timer5"
+     "st,stm32-mfd-timer6"
+     "st,stm32-mfd-timer7"
+     "st,stm32-mfd-timer8"
+     "st,stm32-mfd-timer9"
+     "st,stm32-mfd-timer10"
+     "st,stm32-mfd-timer11"
+     "st,stm32-mfd-timer12"
+     "st,stm32-mfd-timer13"
+     "st,stm32-mfd-timer14"

We don't normally number devices.

What's stopping you from simply doing:

        pwm1: pwm1 at 40010000 {
                compatible = "st,stm32-pwm";
        };
        pwm2: pwm1 at 40020000 {
                compatible = "st,stm32-pwm";
        };
        pwm3: pwm1 at 40030000 {
                compatible = "st,stm32-pwm";
        };

Because each instance of the hardware is slightly different: number of
pwm channels, triggers capabilities, etc ..
so I need to distinguish them.
Since it look to be a problem I will follow your suggestion and add a
property this driver to be able to identify each instance.
Do you think that "id" parameter (integer for 1 to 14) is acceptable ?

Unfortunately not. IDs aren't allowed in DT.

What about "pwm-chans" and "trigger"?

pwm-chans              : Number of available channels available

For pwm I need those 4 properties:
st,pwm-number: the number of PWM devices

st,pwm-num-chan is already documented.

Please use that instead of creating new properties.

st,complementary: if exist have complementary ouput
st,32bit-counter: if exist have 32 bits counter
st,breakinput-polarity: if set enable break input feature.

Is it acceptable from pwm maintainer point of view ?

quoted

trigger                : Boolean value specifying whether a timer is present

Following our discussion on IRC I will try to code for your proposal:

advanced-timer at 40010000 {
        compatible = "st,stm32-advanced-timer";
        reg = <0x40010000 0x400>;
        clocks = <&rcc 0 160>;
        clock-names = "clk_int";

        pwm at 0 {
                compatible = "st,stm32-pwm";
                st,pwm-number= <4>;
                st,complementary;
                st,breakinput;
        };

        timer at 0 {
                reg = <1>;
                compatible = "st,stm32-iio-timer";
                interrupts = <27>;
                triggers = <5 2 3 4>;
        };
};

triggers parameter will be used to know which trigger are valid for
the IIO device

Except for "st,pwm-number" as mentioned above, this looks good to me.

Rob, would what do you think?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
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