RE: RFC: imx8qm: imx-scu-clk: probe of clk failed

From: Anson Huang <anson.huang@nxp.com>
To: Oliver Graute <oliver.graute@gmail.com>,
	Aisheng Dong <aisheng.dong@nxp.com>
Cc: "festevam@gmail.com" <festevam@gmail.com>,
	dl-linux-imx <linux-imx@nxp.com>,
	"linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>,
	"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
	"mturquette@baylibre.com" <mturquette@baylibre.com>,
	Leonard Crestez <leonard.crestez@nxp.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: RE: RFC: imx8qm: imx-scu-clk: probe of clk failed
Date: Fri, 28 Feb 2020 00:40:06 +0000	[thread overview]
Message-ID: <DB3PR0402MB3916849150B4778E117B6F86F5E80@DB3PR0402MB3916.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20200227153110.GD16310@optiplex>

Hi, Oliver

> Subject: Re: RFC: imx8qm: imx-scu-clk: probe of clk failed
> 
> On 27/02/20, Oliver Graute wrote:
> > Hello Aisheng,
> > Hello Anson,
> >
> > I get the following imx-scu errors when using Linux version
> > 5.6.0-rc1-next-20200214 with scfw Build 3353, Commit 494c97f3
> >
> > It seems that important clocks are off somehow and that lpspi isn't
> > working because of that. What is the best way to debug such issues?
> >
> > [    1.103799] imx-scu scu: NXP i.MX SCU Initialized
> > [    1.111383] a35_clk: failed to get clock rate -22
> 
> After some deeper digging I saw that the reason for "a35_clk: failed" is an
> IMX_SC_ERR_PARM = 3. Because he trys to get the resource SC_R_A35 which
> is only available on imx8qxp and not on imx8qm. No clue why he try that
> instead of SC_R_A53.

You are running on i.MX8QM board, right? Is it because the A35/A53/A72 clocks
are registered on same clock driver, so that clock core will calculate their rate during
clock tree setup? But even A35 clock get rate failed on i.MX8QM, I don't see it will
impact lpspi.

i.MX8QM is already supported on our internal v5.4 tree, there are some changes in clk-scu.c,
I pasted some code piece as below, maybe you can compare the difference and have a try?

276 static int clk_scu_atf_set_cpu_rate(struct clk_hw *hw, unsigned long rate,
277                                     unsigned long parent_rate)
278 {
279         struct clk_scu *clk = to_clk_scu(hw);
280         struct arm_smccc_res res;
281         unsigned long cluster_id;
282
283         if (clk->rsrc_id == IMX_SC_R_A35 || clk->rsrc_id == IMX_SC_R_A53)
284                 cluster_id = 0;
285         else if (clk->rsrc_id == IMX_SC_R_A72)
286                 cluster_id = 1;
287         else
288                 return -EINVAL;

471         init.name = name;
472         init.ops = &clk_scu_ops;
473         if (rsrc_id == IMX_SC_R_A35 || rsrc_id == IMX_SC_R_A53 || rsrc_id == IMX_SC_R_A72)
474                 init.ops = &clk_scu_cpu_ops;
475         else if (rsrc_id == IMX_SC_R_PI_0_PLL)
476                 init.ops = &clk_scu_pi_ops;
477         else
478                 init.ops = &clk_scu_ops;

646 static int imx_clk_scu_attach_pd(struct device *dev, u32 rsrc_id)
647 {
648         struct of_phandle_args genpdspec = {
649                 .np = pd_np,
650                 .args_count = 1,
651                 .args[0] = rsrc_id,
652         };
653
654         if ((rsrc_id == IMX_SC_R_A35) || (rsrc_id == IMX_SC_R_A53) ||
655             (rsrc_id == IMX_SC_R_A72))
656                 return 0;

Anson