On 22.08.2019 23:06, Andrey Smirnov wrote:

quoted

On 31.07.2019 21:01, Andrey Smirnov wrote:

quoted

With commit b5bbe2235361 ("usb: phy: mxs: Disable external charger
detect in mxs_phy_hw_init()") in tree all of the necessary charger
setup is done by the USB PHY driver which covers all of the affected
i.MX6 SoCs.

NOTE: Imx_anatop_init() was also called for i.MX7D, but looking at its
datasheet it appears to have a different USB PHY IP block, so
executing i.MX6 charger disable configuration seems unnecessary.

-void __init imx_anatop_init(void)
-{
-     anatop = syscon_regmap_lookup_by_compatible("fsl,imx6q-anatop");
-     if (IS_ERR(anatop)) {
-             pr_err("%s: failed to find imx6q-anatop regmap!\n", __func__);
-             return;
-     }

This patch breaks suspend on imx6 in linux-next because the "anatop"
regmap is no longer initialized. This was found via bisect but
no_console_suspend prints a helpful stack anyway:

(regmap_read) from [<c01226e4>] (imx_anatop_enable_weak2p5+0x28/0x70)
(imx_anatop_enable_weak2p5) from [<c0122744>]
(imx_anatop_pre_suspend+0x18/0x64)
(imx_anatop_pre_suspend) from [<c0124434>] (imx6q_pm_enter+0x60/0x16c)
(imx6q_pm_enter) from [<c018c8a4>] (suspend_devices_and_enter+0x7d4/0xcbc)
(suspend_devices_and_enter) from [<c018d544>] (pm_suspend+0x7b8/0x904)
(pm_suspend) from [<c018b1b4>] (state_store+0x68/0xc8)

My bad, completely missed that fact that anatop was a global variable
in  imx_anatop_init(). Sorry about that.

quoted

Minimal fix looks like this:

--- arch/arm/mach-imx/anatop.c
+++ arch/arm/mach-imx/anatop.c

@@ -111,6 +111,12 @@ void __init imx_init_revision_from_anatop(void)
           digprog = readl_relaxed(anatop_base + offset);
           iounmap(anatop_base);

+       anatop = syscon_regmap_lookup_by_compatible("fsl,imx6q-anatop");
+       if (IS_ERR(anatop)) {
+               pr_err("failed to find imx6q-anatop regmap!\n");
+               return;
+       }

Since all SOCs that called imx_anatop_init also call
imx_init_revision_from_anatop this might be an acceptable solution,
unless there is some limitation preventing early regmap lookup.

Would making every function that uses anatop explicitly request it via
syscon_regmap_lookup_by_compatible("fsl,imx6q-anatop") be too much of
a code duplication? This way we won't need to worry if
imx_init_revision_from_anatop() was called before any of them are
used.

It's only used from pre_suspend and post_suspend, everything else in 
arch/arm/mach-imx/anatop.c is static. Doing a lookup every time would be 
silly, it's fine to let this be global.

I was wondering if maybe imx_init_revision could somehow end up getting 
called before syscon/regmap core init.

--
Regards,
Leonard

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