On Wed, 23 Nov 2016, Benjamin Gaignard wrote:

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.

Hopefully the one that best fits.

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
trigger		       : Boolean value specifying whether a timer is present

Why can't you let of_platform_populate() register the devices for you?
Then you can get rid of all of the meaningless numbers all over the place.

quoted

quoted

+- reg :                      Physical base address and length of the controller's
+                     registers.
+- clock-names:               Set to "mfd_timer_clk".

Only one but I use devm_regmap_init_mmio_clk() to avoid calling
clk_{enable/disable}
everywhere in the drivers when reading/writing regsister.
devm_regmap_init_mmio_clk() find the clock by it name that why I have
put it here
In the doc this clock in named "clk_int" I will use this name.

Please reply *below* the quote.

But okay, "clk_int" sounds like a more suitable name.

quoted

How many clocks are there?

If only 1, you don't need this property.

"mfd_timer_clk" is not the correct name.

What is it called in the datasheet?

quoted

+- clocks:            Phandle of the clock used by the timer module.

"Phandle to the clock ..."

quoted

+                     For Clk properties, please refer to [1].
+- interrupts :               Reference to the timer interrupt

Reference to?

See how other binding documents describe this property.

quoted

+Optional parameters:
+- resets :           Reference to a reset controller asserting the timer

As above.

quoted

+Optional subnodes:

Either use ":" or " :" or "<tab>:", but keep it consistent.

quoted

+- pwm:                       See Documentation/devicetree/bindings/pwm/pwm-stm32.txt
+- iiotimer:          See Documentation/devicetree/bindings/iio/timer/stm32-iio-timer.txt
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt

Use the relative paths "../clock/", "../pwm/", "../iio/".

OK

quoted

quoted

+Example:
+     mfd_timer1: mfdtimer1 at 40010000 {

This is not an "MFD timer".  MFD is a Linuxisum.

quoted

+             compatible = "st,stm32-mfd-timer1";

Better description required.

quoted

+             reg = <0x40010000 0x400>;
+             clocks = <&rcc 0 160>;
+             clock-names = "mfd_timer_clk";
+             interrupts = <27>;
+
+             pwm1: pwm1 at 40010000 {
+                     compatible = "st,stm32-pwm1";
+             };
+
+             iiotimer1: iiotimer1 at 40010000 {
+                     compatible = "st,stm32-iio-timer1";
+             };
+     };

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog