Hi,
On 11/01/18 10:15, Icenowy Zheng wrote:
>
>
> 于 2018年1月11日 GMT+08:00 下午6:08:19, Andre Przywara <andre.przywara@xxxxxxx> 写到:
>> Hi,
>>
>> On 06/01/18 04:23, Icenowy Zheng wrote:
>>> The Allwinner H6 pin controllers (both the main one and the CPUs one)
>>> have no bus gate clocks.
>>>
>>> Add support for this kind of pin controllers.
>>>
>>> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
>>> ---
>>> drivers/pinctrl/sunxi/pinctrl-sunxi.c | 30
>> ++++++++++++++++++++----------
>>> drivers/pinctrl/sunxi/pinctrl-sunxi.h | 1 +
>>> 2 files changed, 21 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
>> b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
>>> index 4b6cb25bc796..68cd505679d9 100644
>>> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
>>> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
>>> @@ -1182,7 +1182,12 @@ static int sunxi_pinctrl_setup_debounce(struct
>> sunxi_pinctrl *pctl,
>>> unsigned int hosc_div, losc_div;
>>> struct clk *hosc, *losc;
>>> u8 div, src;
>>> - int i, ret;
>>> + int i, ret, clk_count;
>>> +
>>> + if (pctl->desc->without_bus_gate)
>>> + clk_count = 2;
>>> + else
>>> + clk_count = 3;
>>>
>>> /* Deal with old DTs that didn't have the oscillators */
>>> if (of_count_phandle_with_args(node, "clocks", "#clock-cells") !=
>> 3)
Just spotted: I guess you wanted to compare against that computed value
here?
But I wonder if we can get rid of this check at all? Don't we rely on
clock-names and input-debounce anyway? So we will bail out later anyway
if the DT does not have those?
Why do we need this check then?
>>> @@ -1360,15 +1365,19 @@ int sunxi_pinctrl_init_with_variant(struct
>> platform_device *pdev,
>>> goto gpiochip_error;
>>> }
>>>
>>> - clk = devm_clk_get(&pdev->dev, NULL);
>>> - if (IS_ERR(clk)) {
>>> - ret = PTR_ERR(clk);
>>> - goto gpiochip_error;
>>> - }
>>> + if (!desc->without_bus_gate) {
>>
>> Do we really need explicit support for that case?
>> Can't we have something that works automatically?
>
> It can be a sanity check. When a SoC comes with bus gate
> support but no apb is provided, there's something wrong.
>
>>
>> if (node has clock-names property) (A)
>> use clocks as enumerated and named there
>> else if (node has one clock reference) (B)
>> use this as gate clock, no debounce support
>> else if (node has no clock property at all) (C)
>> no gate clock needed, no debounce support
>
> This should not happen in practice, as no gate clock is implemented
> after debounce.
But still you seem to somewhat support it with your changes above - by
bailing out if there aren't two clocks.
This kind of explicitly checking for a certain number of clocks sounds
not very robust and future proof to me, hence the suggestion to get rid
of it.
Cheers,
Andre.
>>
>> On top of that we should add the clock-names property to all DTs, even
>> for those with only a "apb" clock. Shouldn't hurt existing kernels.
>> Possibly even add debounce support for those on the way, if applicable.
>>
>> So we would just support case (B) and (C) for legacy reasons.
>>
>> Does that make sense?
>>
>> Cheers,
>> Andre.
>>
>>> + clk = devm_clk_get(&pdev->dev, NULL);
>>> + if (IS_ERR(clk)) {
>>> + ret = PTR_ERR(clk);
>>> + goto gpiochip_error;
>>> + }
>>>
>>> - ret = clk_prepare_enable(clk);
>>> - if (ret)
>>> - goto gpiochip_error;
>>> + ret = clk_prepare_enable(clk);
>>> + if (ret)
>>> + goto gpiochip_error;
>>> + } else {
>>> + clk = NULL;
>>> + }
>>>
>>> pctl->irq = devm_kcalloc(&pdev->dev,
>>> pctl->desc->irq_banks,
>>> @@ -1425,7 +1434,8 @@ int sunxi_pinctrl_init_with_variant(struct
>> platform_device *pdev,
>>> return 0;
>>>
>>> clk_error:
>>> - clk_disable_unprepare(clk);
>>> + if (clk)
>>> + clk_disable_unprepare(clk);
>>> gpiochip_error:
>>> gpiochip_remove(pctl->chip);
>>> return ret;
>>> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
>> b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
>>> index 11b128f54ed2..ccb6230f0bb5 100644
>>> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
>>> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
>>> @@ -113,6 +113,7 @@ struct sunxi_pinctrl_desc {
>>> unsigned irq_bank_base;
>>> bool irq_read_needs_mux;
>>> bool disable_strict_mode;
>>> + bool without_bus_gate;
>>> };
>>>
>>> struct sunxi_pinctrl_function {
>>>
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