On 2016/8/1 20:43, Mark Rutland wrote:
> On Mon, Aug 01, 2016 at 09:42:08AM +0800, Jian Yuan wrote:
>> From: yuanjian <yuanjian12@xxxxxxxxxxxxx>
>>
>> Add pwm driver for HiSilicon BVT SOCs
>>
>> Reviewed-by: Jiancheng Xue <xuejiancheng@xxxxxxxxxxxxx>
>> Signed-off-by: Jian Yuan <yuanjian12@xxxxxxxxxxxxx>
>> ---
>> .../devicetree/bindings/pwm/pwm-hibvt.txt | 18 ++
>> drivers/pwm/Kconfig | 10 +
>> drivers/pwm/Makefile | 1 +
>> drivers/pwm/pwm-hibvt.c | 272 +++++++++++++++++++++
>> 4 files changed, 301 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/pwm/pwm-hibvt.txt
>> create mode 100644 drivers/pwm/pwm-hibvt.c
>>
>> diff --git a/Documentation/devicetree/bindings/pwm/pwm-hibvt.txt b/Documentation/devicetree/bindings/pwm/pwm-hibvt.txt
>> new file mode 100644
>> index 0000000..4efd83e
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pwm/pwm-hibvt.txt
>> @@ -0,0 +1,18 @@
>> +Hisilicon PWM controller
>> +
>> +Required properties:
>> + - compatible: should be "hisilicon,hibvt-pwm" and one of the following:
>> + "hisilicon,hi3516cv300-pwm".
>
> I take it "hisilicon,hibvt-pwm" is the fallback entry.
>
> It would be good to note that explicitly.
>
I do not understand what the fallback entry means.
"hisilicon,hibvt-pwm" is a general compatible string, which is available for most HiSilicon BVT SOCs.
Howerver, "hisilicon,hi3516cv300-pwm" is specially for hi3516cv300.
Maybe I should note the compatible string as described above, right?
>> + - reg: physical base address and length of the controller's registers.
>> + - clocks: phandle and clock specifier of the PWM reference clock.
>> + - resets: offset address and offset bit for reset or unreset of the controller.
>> + - pwm-nums: pwm number of the controller.
>
> This should be 'num-pwms'.
>
> I assume this is the number of PWMs exposed by this controller. Is this
> not probeable, or dicoverable based on the compatible string?
>
> How does this vary in practice?
>
"pwm-nums" means the maximum number of PWMS that this controller can support, which is the hardware capability.
E.g.,HI3516CV300 PWM controller supports 4 PWM, while other chips support 8 PWM.
I agree that the PWM number is probeable based on the compatible string. I shall change it, thanks.
>> +
>> +Example:
>> + pwm: pwm@12130000 {
>> + compatible = "hisilicon,hibvt-pwm";
>
> This is missing "hisilicon,hi3516cv300-pwm" as per the requirements of
> the binding.
>
Ok, it's right. I'll fix it in next v2 patch.
>> + reg = <0x12130000 0x10000>;
>> + clocks = <&crg_ctrl HI3516CV300_PWM_CLK>;
>> + resets = <&crg_ctrl 0x38 0>;
>> + pwm-nums = <4>;
>> + };
>
> Thanks,
> Mark.
>
> .
>
Thanks,
Jian.
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