Thread (6 messages) 6 messages, 2 authors, 2019-08-01

Re: [PATCH] serial: imx: Avoid probe failure in case of missing gpiolib

From: Schrempf Frieder <hidden>
Date: 2019-08-01 09:28:43
Also in: linux-serial, lkml

Hi Uwe,

On 01.08.19 10:48, Uwe Kleine-König wrote:
On Thu, Aug 01, 2019 at 08:18:05AM +0000, Schrempf Frieder wrote:
quoted
From: Frieder Schrempf <redacted>

If CONFIG_GPIOLIB is not enabled, mctrl_gpio_init() will return
-ENOSYS and cause the probing of the imx UART to fail. As the
GPIOs are optional, we should continue probing in this case.
Is this really still the case? On which version did you hit this
problem?
Yes, I think it is. I used v5.2.5, that already has d99482673f95.
I would expect that is gone with
d99482673f950817b30caf3fcdfb31179b050ce1 if not earlier.
I think this is a different problem. If CONFIG_GPIOLIB is disabled, 
mctrl_gpio_init() returns -ENOSYS unconditionally here: [1]. The 
existing patch (d99482673f95) seems to handle the case when 
CONFIG_GPIOLIB is enabled, but no or not all GPIOs are given in the dtb.

The sh-sci.c driver has a similar check to skip this case: [2].

Regards,
Frieder

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/serial_mctrl_gpio.h#n121
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/sh-sci.c#n3290
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