As per the datasheet, manage the IO and value states to implement
open-source/open-drain, but do this by falling back to gpiolib's
emulation.
This commit simply makes the behaviour explicit for clarity, rather than
relying on the implicit return of -ENOTSUPP to trigger the emulation.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Each GPIO in the Aspeed GPIO controller can choose one of four input
debounce states: to disable debouncing for an input, or select from one
of three programmable debounce timer values. Each GPIO in a
four-bank-set is assigned one bit in each of two debounce configuration
registers dedicated to the set, and selects a debounce state by
configuring the two bits to select one of the four options.
The limitation on debounce timer values is managed by mapping offsets
onto a configured timer value and keeping count of the number of users
a timer has. Timer values are configured on a first-come-first-served
basis.
A small twist in the hardware design is that the debounce configuration
register numbering is reversed with respect to the binary representation
of the debounce timer of interest (i.e. debounce register 1 represents
bit 1, and debounce register 2 represents bit 0 of the timer numbering).
Tested on an AST2500EVB with additional inspection under QEMU's
romulus-bmc machine.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
1736f75d35 is a (v2) patch which had
unresolved review comments[1]. Address the comments by removing the use
of macros from the consumer header (this patch represents the diff
between v2 and v3[2]).
[1] https://lkml.org/lkml/2017/1/26/337
[2] https://lkml.org/lkml/2017/1/26/786
Fixes: 1736f75d35 ("gpio: aspeed: Add banks Y, Z, AA, AB and AC")
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This is less straight-forward than one would hope, as some banks only
have 4 pins rather than 8, others are output only, yet more (W and
X, already supported) are input-only, and in the case of the g4 SoC bank
AC doesn't exist.
Add some structs to describe the varying properties of different banks
and integrate mechanisms to deny requests for unsupported
configurations.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The Aspeed SoCs have more GPIOs than can be represented with A-Z. The
documentation uses two letter names such as AA and AB, so make the names
a three-character array in the bank struct to accommodate this.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Remove unneeded error handling on the result of a call
to platform_get_resource() when the value is passed to
devm_ioremap_resource().
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
In case of error, the function devm_ioremap_resource() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The build complains about missing MODULE_LICENSE() in
the Aspeed GPIO driver. The license is evident from the
file header, put in "GPL".
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The Aspeed SoCs contain GPIOs banked by letter, where each bank contains
8 pins. The GPIO banks are then grouped in sets of four in the register
layout.
The implementation exposes multiple banks through the one driver and
requests and releases pins via the pinctrl subsystem. The hardware
supports generation of interrupts from all GPIO-capable pins.
A number of hardware features are not yet supported: Configuration of
interrupt direction (ARM or LPC), debouncing, and WDT reset tolerance
for output ports.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Andrew Jeffery
Joel Stanley
Wei Yongjun
Linus Walleij