[PATCH] Revert "serial: imx: remove unbalanced clk_prepare"

[Fabio Estevam]

Hi Greg,

On Tue, Aug 18, 2015 at 12:43 PM, Fabio Estevam
<fabio.estevam at freescale.com> wrote:
> This reverts commit 9e7b399d6528eac33a6fbfceb2b92af209c3454d.
>
> Commit ("9e7b399d6528ea") causes the following warning and sometimes
> also hangs the system:
>
> ------------[ cut here ]------------
>  WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:868 mutex_trylock+0x20c/0x22c()
>  DEBUG_LOCKS_WARN_ON(in_interrupt())
>  Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.2.0-rc7-next-20150818-00001-g14418a6 #4
> Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> Backtrace:
> [<80012f08>] (dump_backtrace) from [<800130a4>] (show_stack+0x18/0x1c)
> r6:00000364 r5:00000000 r4:00000000 r3:00000000
> [<8001308c>] (show_stack) from [<807902b8>] (dump_stack+0x88/0xa4)
> [<80790230>] (dump_stack) from [<8002a604>] (warn_slowpath_common+0x80/0xbc)
> r5:807945c4 r4:80ab3b50
> [<8002a584>] (warn_slowpath_common) from [<8002a6e4>] (warn_slowpath_fmt+0x38/0x40)
> r8:00000000 r7:8131100c r6:8054c3cc r5:8131300c r4:80b0a570
> [<8002a6b0>] (warn_slowpath_fmt) from [<807945c4>] (mutex_trylock+0x20c/0x22c)
> r3:8095d0d8 r2:8095ab28
> [<807943b8>] (mutex_trylock) from [<8054c3cc>] (clk_prepare_lock+0x14/0xf4)
> r7:8131100c r6:be3f0c80 r5:00000037 r4:be3f0c80
> [<8054c3b8>] (clk_prepare_lock) from [<8054dbfc>] (clk_prepare+0x18/0x30)
> r5:00000037 r4:be3f0c80
> [<8054dbe4>] (clk_prepare) from [<8036a600>] (imx_console_write+0x30/0x244)
> r4:812d0bc8 r3:8132b9a4
>
> To reproduce the problem we only need to let the board idle for something
> like 30 seconds.
>
> Tested on a imx6q-sabresd.
>
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>

Could you please consider applying this one for 4.3-rc?

Thanks