Commit Graph

12 Commits

Author SHA1 Message Date
David Howells
d759f90679 Annotate hardware config module parameters in drivers/gpio/
When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image.  Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.

To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify.  The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.

Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.

This patch annotates drivers in drivers/gpio/.

Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
cc: Alexandre Courbot <gnurou@gmail.com>
cc: linux-gpio@vger.kernel.org
2017-04-20 12:02:32 +01:00
William Breathitt Gray
a71dc2537a gpio: 104-idi-48: Add support for GPIO names
This patch sets the gpio_chip names option with an array of GPIO line
names that match the manual documentation for the ACCES 104-IDI-48.
This should make it easier for users to identify which GPIO line
corresponds to a respective GPIO pin on the device.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-02-01 16:03:55 +01:00
William Breathitt Gray
b4e73edee5 gpio: 104-idi-48: Remove unnecessary driver_data set
Setting driver_data was necessary to access private data in the
idi_48_remove function. Now that the idi_48_remove function is gone,
driver_data is no longer used. This patch removes the relevant code.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-02-01 15:59:19 +01:00
William Breathitt Gray
e43fee6034 gpio: 104-idi-48: Utilize devm_ functions in driver probe callback
The devm_ resource manager functions allow memory to be automatically
released when a device is unbound. This patch takes advantage of the
resource manager functions and replaces the gpiochip_add_data call and
request_irq call with the devm_gpiochip_add_data call and
devm_request_irq call respectively. In addition, the idi_48_remove
function has been removed as no longer necessary due to the use of the
relevant devm_ resource manager functions.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-01-26 15:53:24 +01:00
Axel Lin
053ae6499a gpio: 104-idi-48: Fix missing spin_lock_init for ack_lock
Fixes: 9ae482104c ("gpio: 104-idi-48: Clear pending interrupt once in IRQ handler")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-06-13 14:48:10 +02:00
William Breathitt Gray
72bf7443ba gpio: 104-idi-48: Utilize the ISA bus driver
The ACCES 104-IDI-48 series communicates via the ISA bus. As such, it
is more appropriate to use the ISA bus driver over the platform driver
to control the ACCES 104-IDI-48 GPIO driver.

This patch also adds support for multiple devices via the base and irq
module array parameters. Each element of the base array corresponds to a
discrete device; each element of the irq array corresponds to the
respective device addressed in the respective base array element.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-02 09:32:04 -07:00
William Breathitt Gray
5cfc05761b gpio: 104-idi-48: Use devm_request_region
By the time request_region is called in the ACCES 104-IDI-48 GPIO
driver, a corresponding device structure has already been allocated. The
devm_request_region function should be used to help simplify the cleanup
code and reduce the possible points of failure.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-16 00:19:51 +01:00
William Breathitt Gray
22aeddb58d gpio: misc: Pass correct license string to MODULE_LICENSE
The GPIO driver copyright boilerplate lacks the "or
later" verbiage regarding GPL compliant distribution. The MODULE_LICENSE
string should reflect the actual copyright license terms used.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-16 00:19:50 +01:00
William Breathitt Gray
4332e0144f gpio: 104-idi-48: Allow IRQ sharing
The ACCES 104-IDI-48 can differentiate between its own and other
devices' interrupt requests. Therefore, IRQ sharing is possible and
should be permitted.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-01-28 09:43:24 +01:00
Linus Walleij
1f36bec53f gpio: 104-idi-48: use gpiochip data pointer
This makes the driver use the data pointer added to the gpio_chip
to store a pointer to the state container instead of relying on
container_of().

Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-01-05 11:21:01 +01:00
William Breathitt Gray
9ae482104c gpio: 104-idi-48: Clear pending interrupt once in IRQ handler
Performing a read operation on the IRQ Status register will clear the
IRQ latch. Since a read operation on the IRQ Status register must be
performed in the IRQ handler in order to determine if the IRQ was in
fact generated by the device, the IRQ latch is consequently cleared by
the IRQ handler. A spinlock is used to guarantee that each IRQ is
serviced in the order it was received.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
2015-12-22 10:19:49 +01:00
William Breathitt Gray
6ddcf9b486 gpio: Add GPIO support for the ACCES 104-IDI-48
The ACCES 104-IDI-48 family of PC/104 utility boards feature 48
individually optically isolated digital inputs. Enabled inputs feature
change-of-state detection capability; if change-of-state detection is
enabled, an interrupt is fired off if a change of input level
(low-to-high or high-to-low) is detected. Change-of-state IRQs are
enabled/disabled on 8-bit boundaries, for a total of six boundaries.

This driver provides GPIO and IRQ support for these 48 channels of
digital input. The base port address for the device may be configured
via the idi_48_base module parameter. The interrupt line number for the
device may be configured via the idi_48_irq module parameter.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-12-01 09:56:36 +01:00