On 2020/02/11 Dmitry Torokhov [off-list ref] wrote: 

On Mon, Feb 10, 2020 at 06:33:30AM +0000, Horia Geanta wrote:

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On 2/10/2020 4:03 AM, Robin Gong wrote:

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On 2020/02/10 Dmitry Torokhov [off-list ref] wrote:

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On Fri, Feb 07, 2020 at 08:10:22AM +0000, Horia Geanta wrote:

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On 1/30/2020 10:45 PM, André Draszik wrote:

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@@ -140,6 +148,25 @@ static int imx_snvs_pwrkey_probe(struct

platform_device *pdev)

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 	if (pdata->irq < 0)
 		return -EINVAL;

+	pdata->clk = devm_clk_get(&pdev->dev, "snvs-pwrkey");
+	if (IS_ERR(pdata->clk)) {
+		pdata->clk = NULL;

Using devm_clk_get_optional() would simplify error handling.

It sounds to me that this clock is not at all optional and the
driver currently "works" only by accident and therefore optional is not

suitable here.

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Yes, then we need to add all snvs clk in dts for on legacy i.MX
chips in this patchset to avoid any potential function broken.

How many are there? I am not too terribly opposed of having the driver handle
missing clk if there are very many legacy DTSes out there. But then we need to
handle it properly (i.e. current iteration does not handle referral properly for
example).

There are four dtsi which have clock support in snvs-rtc  including i.mx7s/i.mx8mq/8mm/8mn. So for this patch set, it's better update
i.mx8mX dtsi except i.mx7s.

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In that case the DT binding should be updated too, to make the clock
mandatory.

I think this should be done in either case, as as far I understand the part can not
function without the clock and it worked purely by chance on some systems as
something else was turning the clock on.

Yes, for all chips snvs clk management added, snvs clock also has to been add
in snvs_pwrkey dts, but for others legacy chips like i.mx6X which have no snvs
clk management, snvs clock is always on, so no need such clk in snvs_pwrkey
dts either, optional is better.

Thanks.

--
Dmitry