pin is an unsigned int and therefore can never be < 0 so
this check is redundant. Remove the check and the associated
dev_err error message.
Fixes CoverityScan CID#1396438 ("Unsigned compared against 0")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Commit df61b366af26 ("pinctrl: core: Use delayed work for hogs") caused a
regression at least with sh-pfc that is also a GPIO controller as
noted by Geert Uytterhoeven <geert@linux-m68k.org>.
As the original pinctrl_register() has issues calling pin controller
driver functions early before the controller has finished registering,
we can't just revert commit df61b366af26. That would break the drivers
using GENERIC_PINCTRL_GROUPS or GENERIC_PINMUX_FUNCTIONS.
So let's fix the issue with the following steps as a single patch:
1. Revert the late_init parts of commit df61b366af26.
The late_init clearly won't work and we have to just give up
on fixing pinctrl_register() for GENERIC_PINCTRL_GROUPS and
GENERIC_PINMUX_FUNCTIONS.
2. Split pinctrl_register() into two parts
By splitting pinctrl_register() into pinctrl_init_controller()
and pinctrl_create_and_start() we have better control over when
it's safe to call pinctrl_create().
3. Introduce a new pinctrl_register_and_init() function
As suggested by Linus Walleij <linus.walleij@linaro.org>, we
can just introduce a new function for the controllers that need
pinctrl_create() called later.
4. Convert the four known problem cases to use new function
Let's convert pinctrl-imx, pinctrl-single, sh-pfc and ti-iodelay
to use the new function to fix the issues. The rest of the drivers
can be converted later. Let's also update Documentation/pinctrl.txt
accordingly because of the known issues with pinctrl_register().
Fixes: df61b366af26 ("pinctrl: core: Use delayed work for hogs")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
SoC family such as DRA7 family of processors have, in addition
to the regular muxing of pins (as done by pinctrl-single), a separate
hardware module called IODelay which is also expected to be configured.
The "IODelay" module has it's own register space that is independent
of the control module and the padconf register area.
With recent changes to the pinctrl framework, we can now support
this hardware with a reasonably minimal driver by using #pinctrl-cells,
GENERIC_PINCTRL_GROUPS and GENERIC_PINMUX_FUNCTIONS.
It is advocated strongly in TI's official documentation considering
the existing design of the DRA7 family of processors during mux or
IODelay reconfiguration, there is a potential for a significant glitch
which may cause functional impairment to certain hardware. It is
hence recommended to do as little of muxing as absolutely necessary
without I/O isolation (which can only be done in initial stages of
bootloader).
NOTE: with the system wide I/O isolation scheme present in DRA7 SoC
family, it is not reasonable to do stop all I/O operations for every
such pad configuration scheme. So, we will let it glitch when used in
this mode.
Even with the above limitation, certain functionality such as MMC has
mandatory need for IODelay reconfiguration requirements, depending on
speed of transfer. In these cases, with careful examination of usecase
involved, the expected glitch can be controlled such that it does not
impact functionality.
In short, IODelay module support as a padconf driver being introduced
here is not expected to do SoC wide I/O Isolation and is meant for
a limited subset of IODelay configuration requirements that need to
be dynamic and whose glitchy behavior will not cause functionality
failure for that interface.
IMPORTANT NOTE: we take the approach of keeping LOCK_BITs cleared
to 0x0 at all times, even when configuring Manual IO Timing Modes.
This is done by eliminating the LOCK_BIT=1 setting from Step
of the Manual IO timing Mode configuration procedure. This option
leaves the CFG_* registers unprotected from unintended writes to the
CTRL_CORE_PAD_* registers while Manual IO Timing Modes are configured.
This approach is taken to allow for a generic driver to exist in kernel
world that has to be used carefully in required usecases.
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
[tony@atomide.com: updated to use generic pinctrl functions, added
binding documentation, updated comments]
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
