by Yong Wu (吴勇)

[permalink] [raw]

Subject: Re: [PATCH 3/9] memory: mtk-smi: Use clk_bulk instead of the clk ops

On Thu, 2021-07-08 at 11:32 +0200, Krzysztof Kozlowski wrote:
> On 16/06/2021 13:43, Yong Wu wrote:
> > smi have many clocks: apb/smi/gals.
> > This patch use clk_bulk interface instead of the orginal one to simply
> > the code.
> >
> > gals is optional clk(some larbs may don't have gals). use clk_bulk_optional
> > instead. and then remove the has_gals flag.
> >
> > Also remove clk fail logs since bulk interface already output fail log.
> >
> > Signed-off-by: Yong Wu <[email protected]>
> > ---
> > drivers/memory/mtk-smi.c | 124 +++++++++++----------------------------
> > 1 file changed, 34 insertions(+), 90 deletions(-)
> >
> > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> > index c5fb51f73b34..bcd2bf130655 100644
> > --- a/drivers/memory/mtk-smi.c
> > +++ b/drivers/memory/mtk-smi.c
> > @@ -60,9 +60,18 @@ enum mtk_smi_gen {
> > MTK_SMI_GEN2
> > };
> >
> > +#define MTK_SMI_CLK_NR_MAX 4
> > +
> > +static const char * const mtk_smi_common_clocks[] = {
> > + "apb", "smi", "gals0", "gals1", /* glas is optional */
>
> Typo here - glas.

Will Fix. Thanks.

>
> > +};
> > +

[snip]

> > @@ -493,7 +449,7 @@ static int mtk_smi_common_probe(struct platform_device *pdev)
> > struct device *dev = &pdev->dev;
> > struct mtk_smi *common;
> > struct resource *res;
> > - int ret;
> > + int i, ret;
> >
> > common = devm_kzalloc(dev, sizeof(*common), GFP_KERNEL);
> > if (!common)
> > @@ -501,23 +457,13 @@ static int mtk_smi_common_probe(struct platform_device *pdev)
> > common->dev = dev;
> > common->plat = of_device_get_match_data(dev);
> >
> > - common->clk_apb = devm_clk_get(dev, "apb");
> > - if (IS_ERR(common->clk_apb))
> > - return PTR_ERR(common->clk_apb);
> > -
> > - common->clk_smi = devm_clk_get(dev, "smi");
> > - if (IS_ERR(common->clk_smi))
> > - return PTR_ERR(common->clk_smi);
> > + common->clk_num = ARRAY_SIZE(mtk_smi_common_clocks);
> > + for (i = 0; i < common->clk_num; i++)
> > + common->clks[i].id = mtk_smi_common_clocks[i];
> >
> > - if (common->plat->has_gals) {
> > - common->clk_gals0 = devm_clk_get(dev, "gals0");
> > - if (IS_ERR(common->clk_gals0))
> > - return PTR_ERR(common->clk_gals0);
> > -
> > - common->clk_gals1 = devm_clk_get(dev, "gals1");
> > - if (IS_ERR(common->clk_gals1))
> > - return PTR_ERR(common->clk_gals1);
> > - }
> > + ret = devm_clk_bulk_get_optional(dev, common->clk_num, common->clks);
> > + if (ret)
> > + return ret;
>
> How do you handle now missing required clocks?

It looks this is a common issue for this function which supports all the
clocks could be optional. Is there common suggestion for this?

For our case, the apb/smi clocks are required while "gals" are optional.

thus, we should use devm_clk_bulk_get for the necessary clocks and
devm_clk_bulk_get_optional for the optional ones. right?

>
> >
> > /*
> > * for mtk smi gen 1, we need to get the ao(always on) base to config
> > @@ -561,11 +507,9 @@ static int __maybe_unused mtk_smi_common_resume(struct device *dev)
> > u32 bus_sel = common->plat->bus_sel;
> > int ret;
> >
> > - ret = mtk_smi_clk_enable(common);
> > - if (ret) {
> > - dev_err(common->dev, "Failed to enable clock(%d).\n", ret);
> > + ret = clk_bulk_prepare_enable(common->clk_num, common->clks);
> > + if (ret)
> > return ret;
> > - }
> >
> > if (common->plat->gen == MTK_SMI_GEN2 && bus_sel)
> > writel(bus_sel, common->base + SMI_BUS_SEL);
> > @@ -576,7 +520,7 @@ static int __maybe_unused mtk_smi_common_suspend(struct device *dev)
> > {
> > struct mtk_smi *common = dev_get_drvdata(dev);
> >
> > - mtk_smi_clk_disable(common);
> > + clk_bulk_disable_unprepare(common->clk_num, common->clks);
> > return 0;
> > }
> >
> >
>
>
> Best regards,
> Krzysztof

2021-07-12 10:04:22

by Krzysztof Kozlowski

[permalink] [raw]

Subject: Re: [PATCH 3/9] memory: mtk-smi: Use clk_bulk instead of the clk ops

On 11/07/2021 10:29, Yong Wu wrote:
> On Thu, 2021-07-08 at 11:32 +0200, Krzysztof Kozlowski wrote:
>> On 16/06/2021 13:43, Yong Wu wrote:
>>> smi have many clocks: apb/smi/gals.
>>> This patch use clk_bulk interface instead of the orginal one to simply
>>> the code.
>>>
>>> gals is optional clk(some larbs may don't have gals). use clk_bulk_optional
>>> instead. and then remove the has_gals flag.
>>>
>>> Also remove clk fail logs since bulk interface already output fail log.
>>>
>>> Signed-off-by: Yong Wu <[email protected]>
>>> ---
>>> drivers/memory/mtk-smi.c | 124 +++++++++++----------------------------
>>> 1 file changed, 34 insertions(+), 90 deletions(-)
>>>
>>> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
>>> index c5fb51f73b34..bcd2bf130655 100644
>>> --- a/drivers/memory/mtk-smi.c
>>> +++ b/drivers/memory/mtk-smi.c
>>> @@ -60,9 +60,18 @@ enum mtk_smi_gen {
>>> MTK_SMI_GEN2
>>> };
>>>
>>> +#define MTK_SMI_CLK_NR_MAX 4
>>> +
>>> +static const char * const mtk_smi_common_clocks[] = {
>>> + "apb", "smi", "gals0", "gals1", /* glas is optional */
>>
>> Typo here - glas.
>
> Will Fix. Thanks.
>
>>
>>> +};
>>> +
>
> [snip]
>
>>> @@ -493,7 +449,7 @@ static int mtk_smi_common_probe(struct platform_device *pdev)
>>> struct device *dev = &pdev->dev;
>>> struct mtk_smi *common;
>>> struct resource *res;
>>> - int ret;
>>> + int i, ret;
>>>
>>> common = devm_kzalloc(dev, sizeof(*common), GFP_KERNEL);
>>> if (!common)
>>> @@ -501,23 +457,13 @@ static int mtk_smi_common_probe(struct platform_device *pdev)
>>> common->dev = dev;
>>> common->plat = of_device_get_match_data(dev);
>>>
>>> - common->clk_apb = devm_clk_get(dev, "apb");
>>> - if (IS_ERR(common->clk_apb))
>>> - return PTR_ERR(common->clk_apb);
>>> -
>>> - common->clk_smi = devm_clk_get(dev, "smi");
>>> - if (IS_ERR(common->clk_smi))
>>> - return PTR_ERR(common->clk_smi);
>>> + common->clk_num = ARRAY_SIZE(mtk_smi_common_clocks);
>>> + for (i = 0; i < common->clk_num; i++)
>>> + common->clks[i].id = mtk_smi_common_clocks[i];
>>>
>>> - if (common->plat->has_gals) {
>>> - common->clk_gals0 = devm_clk_get(dev, "gals0");
>>> - if (IS_ERR(common->clk_gals0))
>>> - return PTR_ERR(common->clk_gals0);
>>> -
>>> - common->clk_gals1 = devm_clk_get(dev, "gals1");
>>> - if (IS_ERR(common->clk_gals1))
>>> - return PTR_ERR(common->clk_gals1);
>>> - }
>>> + ret = devm_clk_bulk_get_optional(dev, common->clk_num, common->clks);
>>> + if (ret)
>>> + return ret;
>>
>> How do you handle now missing required clocks?
>
> It looks this is a common issue for this function which supports all the
> clocks could be optional. Is there common suggestion for this?
>
> For our case, the apb/smi clocks are required while "gals" are optional.
>
> thus, we should use devm_clk_bulk_get for the necessary clocks and
> devm_clk_bulk_get_optional for the optional ones. right?

Yes, I think that's the solution. Otherwise you might not have proper
clocks leading to accesses to disabled/gated hardware.

Best regards,
Krzysztof