Warnings/Errors while using MMC2 interface in am335x processor

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Posted by Manjunath GR

on Dec 27 2012 04:40 AM

Prodigy30 points

I am using mmc2 interface on am335x processor for SD card.

During device boot up below warning messages are observed.

[ 1.408233] _regulator_get: omap_hsmmc.2 supply vmmc not found, using dummy regulator

[ 1.416503] _regulator_get: omap_hsmmc.2 supply vmmc_aux not found, using dummy regulator

[ 1.430633] omap_hsmmc omap_hsmmc.2: could not set regulator OCR (-22)

[ 1.442993] ------------[ cut here ]------------

[ 1.447845] WARNING: at drivers/regulator/core.c:1446 _regulator_disable+0x104/0x16c()

[ 1.456085] unbalanced disables for dummy

[ 1.460266] Modules linked in:

[ 1.463470] Backtrace:

[ 1.466033] [<c0017978>] (dump_backtrace+0x0/0x110) from [<c0439fdc>] (dump_stack+0x18/0x1c)

[ 1.474853] r6:c06129dc r5:000005a6 r4:ce81dda0 r3:c06e9a08

[ 1.480773] [<c0439fc4>] (dump_stack+0x0/0x1c) from [<c003d584>] (warn_slowpath_common+0x5c/0x6c)

Please let me know what is the cause and how to resolve these warning.

All Replies

Posted by David Paden

on Mar 04 2013 14:50 PM

Intellectual760 points

I know this is a little old, but I think the problem is in the hsmmc file during the pdata_init. The code was probably originally for some other board, so mmc bus "3" (or MMC2) does not get fully initialized. Below is the diff output from my board changes. Note that it could break old code, so maybe it would be better to prevent the fallthrough in the case statement and do a separate check for cpu_is_am33xx() in case 3. I haven't had a chance to confirm it working with wl1271 or an SD card...

Index: arch/arm/mach-omap2/hsmmc.c
===================================================================
--- arch/arm/mach-omap2/hsmmc.c (revision 11)
+++ arch/arm/mach-omap2/hsmmc.c (working copy)
@@ -402,6 +402,8 @@
                }
                break;
        case 2:
+               /* FALLTHROUGH */
+       case 3:
                if (cpu_is_omap3517() || cpu_is_omap3505())
                        mmc->slots[0].set_power = am35x_hsmmc2_set_power;

@@ -414,8 +416,7 @@
                        c->caps &= ~MMC_CAP_8_BIT_DATA;
                        c->caps |= MMC_CAP_4_BIT_DATA;
                }
-               /* FALLTHROUGH */
-       case 3:
+
                if (mmc->slots[0].features & HSMMC_HAS_PBIAS) {
                        /* off-chip level shifting, or none */
                        mmc->slots[0].before_set_reg = hsmmc23_before_set_reg;

Posted by Manjunath GR

on Mar 05 2013 01:07 AM

Verified Answer

Verified by Manjunath GR

Prodigy30 points

Thanks David.

This fixed the issue.