4 Commits

Author SHA1 Message Date
Mark Featherston
54fd6b2eb1 gpio: ts4900: Do not set DAT and OE together
[ Upstream commit 03fe003547975680fdb9ff5ab0e41cb68276c4f2 ]

This works around an issue with the hardware where both OE and
DAT are exposed in the same register. If both are updated
simultaneously, the harware makes no guarantees that OE or DAT
will actually change in any given order and may result in a
glitch of a few ns on a GPIO pin when changing direction and value
in a single write.

Setting direction to input now only affects OE bit. Setting
direction to output updates DAT first, then OE.

Fixes: 9c6686322d74 ("gpio: add Technologic I2C-FPGA gpio support")
Signed-off-by: Mark Featherston <mark@embeddedTS.com>
Signed-off-by: Kris Bahnsen <kris@embeddedTS.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-03-16 13:21:46 +01:00
Thierry Reding
81317c5a08 gpio: ts4900: Use of_device_get_match_data()
Use of_device_get_match_data() instead of open-coding it.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-05-16 14:35:24 +02:00
Julia Lawall
e35b5ab0a7 gpio: constify gpio_chip structures
These structures are only used to copy into other structures, so declare
them as const.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct gpio_chip i@p = { ... };

@ok@
identifier r.i;
expression e;
position p;
@@
e = i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct gpio_chip e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct gpio_chip i = { ... };
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-09-13 10:35:56 +02:00
Lucile Quirion
9c6686322d gpio: add Technologic I2C-FPGA gpio support
This driver is generic and aims to support all Technologic Systems's
boards embedding FPGA GPIOs with an I2C interface.

This driver supports TS-4900, TS-7970, TS-7990 and TS-4100 series.

Signed-off-by: Lucile Quirion <lucile.quirion@savoirfairelinux.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-08-19 11:04:53 +02:00