On 2020/02/11 André Draszik [off-list ref] wrote:

Hi,

On Tue, 2020-02-11 at 01:54 +0000, Robin Gong wrote:

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

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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.

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Thanks.

It seems to me though that the clock should really be moved into the (parent)
SNVS node itself, rather than duplicating the clock in the the power key node
and in the RTC node. Is that possible? (I don't know)...

That's possible but much code changes need to be added into snvs-rtc/snvs_pwrkey
driver. Independent patch is better.

To summarise, I'll post an updated patchset within the next couple days so to:

* keep the clock optional (for i.MX6 platforms)
* convert to devm_clk_get_optional()
* only enable the clock in interrupt handler and
imx_imx_snvs_check_for_events()
  but not during driver loading
* update all four DTSIs: imx8mm.dtsi imx8mn.dtsi imx8mq.dtsi imx7s.dtsi
  Note that I'll only be able to test onn the i.MX7

Correct.

Cheers,
Andre'