Input: add driver for Silead touchscreens

This driver adds support for Silead touchscreens. It has been tested
with GSL1680 and GSL3680 touch panels.

It supports ACPI and device tree enumeration. Screen resolution,
the maximum number of fingers supported and firmware name are
configurable.

Signed-off-by: Robert Dolca <robert.dolca@intel.com>
Signed-off-by: Daniel Jansen <djaniboe@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: silead - remove some dead code

buf[0] is an unsigned char.  touch_nr is an int.  The test for negative
here doesn't make sense so I have removed it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: silead - use devm_gpiod_get

The silead code is using devm_foo for everything (and does not free
any resources). Except that it is using gpiod_get instead of
devm_gpiod_get (but is not freeing the gpio_desc), change this
to use devm_gpiod_get so that the gpio will be properly released.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: silead_gsl1680 - document firmware-name, fix implementation

The driver has supported touchscreen-fw-name to specify the firmware to
load since it has been merged, but this was omitted from the dt-binding
documentation.

During review of adding touchscreen-fw-name to the binding documentation
it was brought up that there is a standard property name called
"firmware-name" for this, which should be used.

Since there are no users of touchscreen-fw-name yet, this commit
adds documentation of "firmware-name" to the dt-binding documentation
and switches the driver over to use this.

This commit also makes the driver add a "silead/" prefix to the
firmware name from dt before calling request_firmware. That the
firmware files are stored under /lib/firmware/silead under Linux
is an implementation detail and does not belong in devicetree.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: silead_gsl1680 - use "silead/" prefix for firmware loading

The silead touch-controller ICs use a different firmware per digitizer /
tablet model. So there are going to be quite a few of then and they really
should be under a separate subdir.

This commit prefixes the default firmware names with "silead/" just like
we are already doing for devicetree specified firmware names.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: silead - add OF device ID table

The driver doesn't have a struct of_device_id table but supported devices
are registered via Device Trees. This is working on the assumption that a
I2C device registered via OF will always match a legacy I2C device ID and
that the MODALIAS reported will always be of the form i2c:<device>.

But this could change in the future so the correct approach is to have an
OF device ID table if the devices are registered via OF.

As pointed by Hans de Goede, there's no mssl1680 and this is just used in
some ACPI systems to identify the gsl1680 chip. So isn't included in the
OF device ID table since a DT should use the proper device name instead.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input: back-port silead.c: pos[i] handling/assignment

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

Input: back-port silead.c: invert_x/y & swap_xy

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

Input: silead: retry firmware load

If we get ENOENT when trying to load the firmware, this can just mean
that the rootfs is not mounted yet. Return EPROBE_DEFER so the probe
is retried later.

To prevent an infinite probe loop when the firmware does not exist at
all, the retries are capped to 10.

Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 4f569b311042..5540b1990b98 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1046,6 +1046,18 @@ config TOUCHSCREEN_PCAP
 	  To compile this driver as a module, choose M here: the
 	  module will be called pcap_ts.
 
+config TOUCHSCREEN_SILEAD
+	tristate "Silead I2C touchscreen"
+	depends on I2C
+	help
+	  Say Y here if you have the Silead touchscreen connected to
+	  your system.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called silead.
+
 config TOUCHSCREEN_ST1232
 	tristate "Sitronix ST1232 touchscreen controllers"
 	depends on I2C