lkml.org 
[lkml]   [2018]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4 4/8] dt-bindings: Add doc for the Ingenic TCU drivers
Hi Rob,

Le mer. 28 mars 2018 à 18:28, Rob Herring <robh@kernel.org> a écrit :
> On Wed, Mar 28, 2018 at 10:33 AM, Paul Cercueil
> <paul@crapouillou.net> wrote:
>> Le 2018-03-27 16:46, Rob Herring a écrit :
>>>
>>> On Sun, Mar 18, 2018 at 12:28:57AM +0100, Paul Cercueil wrote:
>>>>
>>>> Add documentation about how to properly use the Ingenic TCU
>>>> (Timer/Counter Unit) drivers from devicetree.
>>>>
>>>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>>> ---
>>>> .../bindings/clock/ingenic,tcu-clocks.txt | 42
>>>> ++++++++++++++++
>>>> .../bindings/interrupt-controller/ingenic,tcu.txt | 39
>>>> +++++++++++++++
>>>> .../devicetree/bindings/mfd/ingenic,tcu.txt | 56
>>>> ++++++++++++++++++++++
>>>> .../devicetree/bindings/timer/ingenic,tcu.txt | 41
>>>> ++++++++++++++++
>>>> 4 files changed, 178 insertions(+)
>>>> create mode 100644
>>>> Documentation/devicetree/bindings/clock/ingenic,tcu-clocks.txt
>>>> create mode 100644
>>>>
>>>> Documentation/devicetree/bindings/interrupt-controller/ingenic,tcu.txt
>>>> create mode 100644
>>>> Documentation/devicetree/bindings/mfd/ingenic,tcu.txt
>>>> create mode 100644
>>>> Documentation/devicetree/bindings/timer/ingenic,tcu.txt
>>>>
>>>> v4: New patch in this series. Corresponds to V2 patches 3-4-5
>>>> with
>>>> added content.
>>>> +/ {
>>>> + tcu: mfd@10002000 {
>>>> + compatible = "ingenic,tcu", "simple-mfd",
>>>> "syscon";
>>>> + reg = <0x10002000 0x1000>;
>>>> + #address-cells = <1>;
>>>> + #size-cells = <1>;
>>>> + ranges = <0x0 0x10002000 0x1000>;
>>>> +
>>>> + tcu_timer: timer@10 {
>>>> + compatible = "ingenic,jz4740-tcu";
>>>> + reg = <0x10 0xff0>;
>>>> +
>>>> + clocks = <&tcu_clk 0>, <&tcu_clk 1>,
>>>> <&tcu_clk
>>>> 2>, <&tcu_clk 3>,
>>>> + <&tcu_clk 4>, <&tcu_clk
>>>> 5>,
>>>> <&tcu_clk 6>, <&tcu_clk 7>;
>>>> + clock-names = "timer0", "timer1",
>>>> "timer2",
>>>> "timer3",
>>>> + "timer4",
>>>> "timer5",
>>>> "timer6", "timer7";
>>>> +
>>>> + interrupt-parent = <&tcu_irq>;
>>>> + interrupts = <0 1 2 3 4 5 6 7>;
>>>
>>>
>>> Thinking about this some more... You simply have 8 timers (and no
>>> other
>>> functions?) with some internal clock and irq controls for each
>>> timer. I
>>> don't think it really makes sense to create separate clock and irq
>>> drivers in that case. That would be like creating clock drivers for
>>> every clock divider in timers, pwms, uarts, etc. Unless the clocks
>>> get
>>> exposed to other parts of the system, then there is no point.
>>
>>
>> I have 8 timers with some internal clock and IRQ controls, that can
>> be used
>> as PWM.
>
> Please include how you plan to do the PWM support too. I need a
> complete picture of the h/w, not piecemeal, evolving bindings.

Alright.

>> But the TCU also controls the IRQ of the OS Timer (which is
>> separate),
>> as well as masking of the clocks for the OS timer and the watchdog.
>
> The OS timer and watchdog are different blocks outside the TCU? This
> doesn't seem to be the case based on the register definitions.

Their register areas are mostly separate, although contiguous. On the
other
hand, the watchdog and OST can be started/stopped from a bit within a
TCU
register, so they're probably part of the same h/w block.

>> I thought having clean drivers for different frameworks working on
>> the same
>> regmap was cleaner than having one big-ass driver handling
>> everything.
>
> DT is not the only way to instantiate drivers and how one OS splits
> drivers should not define your DT binding. An MFD driver can create
> child devices and a single DT node can be a provider of multiple
> things. It is appropriate for an MFD to have child nodes primarily
> when the sub devices need their own resources defined as properties in
> DT or when the sub device is an IP block reused in multiple devices.
> Just to have a node per driver/provider is not what should drive the
> decision.

The idea is not to have necesarily one node per driver. I just wanted
to keep
it simple.

Regards,
-Paul

\
 
 \ /
  Last update: 2018-03-29 18:01    [W:0.091 / U:2.476 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site