Re: [patch v15 3/4] Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver

From: Joel Stanley <joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org>
To: Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: "Greg KH"
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	"Arnd Bergmann" <arnd-r2nGTMty4D4@public.gmane.org>,
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	"Jiří Pírko" <jiri-rHqAuBHg3fBzbRFIqnYvSA@public.gmane.org>,
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	"David S . Miller"
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	mchehab-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	"Jiri Pirko" <jiri-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Subject: Re: [patch v15 3/4] Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx families JTAG master driver
Date: Thu, 11 Jan 2018 15:54:36 -0800	[thread overview]
Message-ID: <CACPK8Xeb3K9PqynV2xymJwvhkZ9fLKsbodEFYiZtQ+SXXgGA5g@mail.gmail.com> (raw)
In-Reply-To: <CACPK8XfH-4r0mBQYA+BwvUo2+RF8igai2jy+RqTDQcxx2-acsQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Thu, Jan 11, 2018 at 9:50 AM, Joel Stanley <joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org> wrote:
> On Mon, Dec 25, 2017 at 3:53 AM, Oleksandr Shamray <oleksandrs-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> wrote:
>> +jtag: jtag@1e6e4000 {
>> +       compatible = "aspeed,ast2500-jtag";
>> +       reg = <0x1e6e4000 0x1c>;
>> +       clocks = <&clk_apb>;
>
> We've now got a proper clock driver upstream. Can you update the
> example to match the newly added bindings?
>
>  clocks = <&syscon ASPEED_CLK_APB>;
>

I think we need to ensure the reset is deasserted as well. You will need:

 resets = <&syscon ASPEED_RESET_JTAG_MASTER>;

In addition, we need to make sure the reset line is deasserted in the
driver. Take a look at how I did this in the i2c driver:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=edd20e95bca4a5434f264d8ab40d729761479825

+       bus->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
+       if (IS_ERR(bus->rst)) {
+               dev_err(&pdev->dev,
+                       "missing or invalid reset controller device
tree entry");
+               return PTR_ERR(bus->rst);
+       }
+       reset_control_deassert(bus->rst);

Please give this a test with an upstream kernel from a fresh power on.

Cheers,

Joel