Commit Graph

8 Commits

Author SHA1 Message Date
Linus Walleij
07c7b6a525 gpio: mmio: Also read bits that are zero
The code for .get_multiple() has bugs:

1. The simple .get_multiple() just reads a register, masks it
and sets the return value. This is not correct: we only want to
assign values (whether 0 or 1) to the bits that are set in the
mask. Fix this by using &= ~mask to clear all bits in the mask
and then |= val & mask to set the corresponding bits from the
read.

2. The bgpio_get_multiple_be() call has a similar problem: it
uses the |= operator to set the bits, so only the bits in the
mask are affected, but it misses to clear all returned bits
from the mask initially, so some bits will be returned
erroneously set to 1.

3. The bgpio_get_set_multiple() again fails to clear the bits
from the mask.

4. find_next_bit() wasn't handled correctly, use a totally
different approach for one function and change the other
function to follow the design pattern of assigning the first
bit to -1, then use bit + 1 in the for loop and < num_iterations
as break condition.

Fixes: 80057cb417 ("gpio-mmio: Use the new .get_multiple() callback")
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Reported-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Tested-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-01-16 23:42:36 +01:00
Linus Walleij
80057cb417 gpio-mmio: Use the new .get_multiple() callback
It is possible to read all lines of a generic MMIO GPIO chip
with a single register read so support this if we are in
native endianness.

Add an especially quirky callback to read multiple lines for
the variants that require you to read values from the
output registers if and only if the line is set as output.
We managed to do that with a maximum of two register reads,
and just one read if the requested lines are all input or all
output.

Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-30 08:35:32 +01:00
Linus Walleij
24efd94bc3 gpio: mmio: Make pin2mask() a private business
The vtable call pin2mask() was introducing a vtable function call
in every gpiochip callback for a generic MMIO GPIO chip. This was
not exactly efficient. (Maybe link-time optimization could get rid of
it, I don't know.)

After removing all external calls into this API we can make it a
boolean flag in the struct gpio_chip call and sink the function into
the gpio-mmio driver yielding encapsulation and potential speedups.

Cc: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-25 11:25:41 +02:00
Nathan Sullivan
b8c90199b5 gpio: mmio: add support for NI 169445 NAND GPIO
The GPIO-based NAND controller on National Instruments 169445 hardware
exposes a set of simple lines for the control signals.

Signed-off-by: Nathan Sullivan <nathan.sullivan@ni.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-03-23 09:49:06 +01:00
Christian Lamparter
05cc995f4d gpio: mmio: add brcm,bcm6345 support
This patch adds support for the GPIO found in Broadcom's bcm63xx-gpio
chips.
This GPIO controller is used in the following Broadcom SoCs: BCM6338, BCM6345.
It can be used in newer SoCs, without the capability of pin multiplexing.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-08-11 16:17:05 +02:00
Christian Lamparter
c0d30ecfe2 gpio: mmio: add MyBook Live GPIO support
This patch adds support for the Western Digital's
MyBook Live memory-mapped GPIO controllers.

The GPIOs will be supported by the generic driver
for memory-mapped GPIO controllers.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-06-08 11:16:50 +02:00
Álvaro Fernández Rojas
e698613ada gpio: mmio: add DT support for memory-mapped GPIOs
This patch adds support for defining memory-mapped GPIOs which
are compatible with the existing gpio-mmio interface. The generic
library provides support for many memory-mapped GPIO controllers
that are found in various on-board FPGA and ASIC solutions that
are used to control board's switches, LEDs, chip-selects,
Ethernet/USB PHY power, etc.

For setting GPIOs there are three configurations:
	1. single input/output register resource (named "dat"),
	2. set/clear pair (named "set" and "clr"),
	3. single output register resource and single input resource
	   ("set" and dat").

The configuration is detected by which resources are present.
For the single output register, this drives a 1 by setting a bit
and a zero by clearing a bit.  For the set clr pair, this drives
a 1 by setting a bit in the set register and clears it by setting
a bit in the clear register.

For setting the GPIO direction, there are three configurations:
	a. simple bidirectional GPIOs that requires no configuration.
	b. an output direction register (named "dirout")
	   where a 1 bit indicates the GPIO is an output.
	c. an input direction register (named "dirin")
	   where a 1 bit indicates the GPIO is an input.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-06-08 11:15:11 +02:00
Christian Lamparter
e9f4d569fb gpio: rename gpio-generic.c into gpio-mmio.c
This patch renames the gpio-generic.c into gpio-mmio.c.
This is because currently the file only contains code
for a memory-mapped GPIO driver. There isn't any support
for ioports or other resource type.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-04-29 16:14:32 +02:00