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

On Thu, Jan 11, 2018 at 9:50 AM, Joel Stanley [off-list ref] wrote:

On Mon, Dec 25, 2017 at 3:53 AM, Oleksandr Shamray [off-list ref] wrote:

quoted

+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