linux_dsm_epyc7002/drivers/w1/masters
Linus Walleij e0fc62a655 w1: w1-gpio: Convert to use GPIO descriptors
The w1 master driver includes a complete open drain emulation
reimplementation among other things.

This converts the driver and all board files using it to use
GPIO descriptors associated with the device to look up the
GPIO wire, as well ass the optional pull-up GPIO line.

When probed from the device tree, the driver will just pick
descriptors and use them right off. For the two board files
in the kernel, we add descriptor lookups so we do not need
to keep any old platform data handling around for the GPIO
lines.

As the platform data is also a state container for this driver,
we augment it to contain the GPIO descriptors.

w1_gpio_write_bit_dir() and w1_gpio_write_bit_val() are gone
since this pair was a reimplementation of open drain emulation
which is now handled by gpiolib.

The special "linux,open-drain" flag is a bit of mishap here:
it has the same semantic as the same flags in I2C: it means
that something in the platform is setting up the line as
open drain behind our back. We handle this the same way as
in I2C.

To drive the pull-up, we need to bypass open drain emulation
in gpiolib for the line, and this is done by driving it high
using gpiod_set_raw_value() which has been augmented to have
the semantic of overriding the open drain emulation.

We also augment the documentation to reflect the way to pass
GPIO descriptors from the machine.

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-12-08 15:32:53 +01:00
..
ds1wm.c w1: ds1wm: add messages to make incorporation in mfd-drivers easier 2017-08-28 17:20:01 +02:00
ds2482.c drivers: w1: Extend 1W master driver DS2482 with module option to support PPM/SPU/1WS features 2017-08-28 17:23:29 +02:00
ds2490.c w1: ds2490: constify usb_device_id and fix space before '[' error 2017-08-28 17:18:19 +02:00
Kconfig w1: mxc_w1: Enable driver compilation with COMPILE_TEST 2014-02-28 15:27:09 -08:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
matrox_w1.c w1: Add subsystem kernel public interface 2017-06-09 11:54:54 +02:00
mxc_w1.c w1: Add subsystem kernel public interface 2017-06-09 11:54:54 +02:00
omap_hdq.c w1: omap-hdq: fix error return code in omap_hdq_probe() 2017-07-17 16:48:15 +02:00
w1-gpio.c w1: w1-gpio: Convert to use GPIO descriptors 2017-12-08 15:32:53 +01:00