[PATCH] Input: synaptics-rmi4: Limit the range of what GPIOs are buttons

By convention the first 6 bits of F30 Ctrl 2 and 3 are used to signify
GPIOs which are connected to buttons. Additional GPIOs may be used as
input GPIOs to signal the touch controller of some event
(ie disable touchpad). These additional GPIOs may meet the criteria of
a button in rmi_f30_is_valid_button() but should not be considered
buttons. This patch limits the GPIOs which are mapped to buttons to just
the first 6.

Signed-off-by: Andrew Duggan <redacted>
Reported-by: Daniel Martin <redacted>
---
I think that this patch will fix the issue with the Lenovo X1 Cover not
being set as a buttonpad. Based on the firmware config for this touchpad
there are additional GPIOs in Ctrl 2 and 3 position 6 and 7 unrelated to
buttons. This is confusing F30 into thinking there are additional buttons.

https://www.spinics.net/lists/linux-input/msg53626.html

 drivers/input/rmi4/rmi_f30.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/input/rmi4/rmi_f30.c b/drivers/input/rmi4/rmi_f30.c
index 34dfee5..a8ed424 100644
--- a/drivers/input/rmi4/rmi_f30.c
+++ b/drivers/input/rmi4/rmi_f30.c

@@ -232,9 +232,11 @@ static int rmi_f30_map_gpios(struct rmi_function *fn,
 	unsigned int trackstick_button = BTN_LEFT;
 	bool button_mapped = false;
 	int i;
+	int button_count = f30->gpioled_count > TRACKSTICK_RANGE_END
+				? TRACKSTICK_RANGE_END : f30->gpioled_count;
 
 	f30->gpioled_key_map = devm_kcalloc(&fn->dev,
-					    f30->gpioled_count,
+					    button_count,
 					    sizeof(f30->gpioled_key_map[0]),
 					    GFP_KERNEL);
 	if (!f30->gpioled_key_map) {

@@ -242,7 +244,7 @@ static int rmi_f30_map_gpios(struct rmi_function *fn,
 		return -ENOMEM;
 	}
 
-	for (i = 0; i < f30->gpioled_count; i++) {
+	for (i = 0; i < button_count; i++) {
 		if (!rmi_f30_is_valid_button(i, f30->ctrl))
 			continue;
 

-- 
2.7.4

On 25 October 2017 at 05:42, Andrew Duggan [off-list ref] wrote:

Thanks, it works with the patch:
Tested-by: Daniel Martin <redacted>

On Oct 24 2017 or thereabouts, Andrew Duggan wrote:

By convention the first 6 bits of F30 Ctrl 2 and 3 are used to signify

I really do not like the "by convention". What if future firmware
developers are willing to add extra buttons and already have trackstick
buttons there, meaning the max 6 button count will be blown up? :/

Still, there is not much we can do (or have a whitelist, but it is a
pain), so:
Acked-By: Benjamin Tissoires <redacted>

Cheers,
Benjamin

On Wed, Oct 25, 2017 at 03:37:35PM +0200, Benjamin Tissoires wrote:

On Oct 24 2017 or thereabouts, Andrew Duggan wrote:

quoted

By convention the first 6 bits of F30 Ctrl 2 and 3 are used to signify

I really do not like the "by convention". What if future firmware
developers are willing to add extra buttons and already have trackstick
buttons there, meaning the max 6 button count will be blown up? :/

Still, there is not much we can do (or have a whitelist, but it is a
pain), so:
Acked-By: Benjamin Tissoires <redacted>

OK, fair enough. I think at some point we'd need to figure out the
haptic/leds/buttons story better, but this should work for now.

Cheers,
Benjamin

quoted

GPIOs which are connected to buttons. Additional GPIOs may be used as
input GPIOs to signal the touch controller of some event
(ie disable touchpad). These additional GPIOs may meet the criteria of
a button in rmi_f30_is_valid_button() but should not be considered
buttons. This patch limits the GPIOs which are mapped to buttons to just
the first 6.

Signed-off-by: Andrew Duggan <redacted>
Reported-by: Daniel Martin <redacted>
---
I think that this patch will fix the issue with the Lenovo X1 Cover not
being set as a buttonpad. Based on the firmware config for this touchpad
there are additional GPIOs in Ctrl 2 and 3 position 6 and 7 unrelated to
buttons. This is confusing F30 into thinking there are additional buttons.

https://www.spinics.net/lists/linux-input/msg53626.html

 drivers/input/rmi4/rmi_f30.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/input/rmi4/rmi_f30.c b/drivers/input/rmi4/rmi_f30.c
index 34dfee5..a8ed424 100644
--- a/drivers/input/rmi4/rmi_f30.c
+++ b/drivers/input/rmi4/rmi_f30.c

@@ -232,9 +232,11 @@ static int rmi_f30_map_gpios(struct rmi_function *fn,
 	unsigned int trackstick_button = BTN_LEFT;
 	bool button_mapped = false;
 	int i;
+	int button_count = f30->gpioled_count > TRACKSTICK_RANGE_END
+				? TRACKSTICK_RANGE_END : f30->gpioled_count;

I changed this to

	int button_count = min_t(u8, f30->gpioled_count, TRACKSTICK_RANGE_END);

quoted

 
 	f30->gpioled_key_map = devm_kcalloc(&fn->dev,
-					    f30->gpioled_count,
+					    button_count,
 					    sizeof(f30->gpioled_key_map[0]),
 					    GFP_KERNEL);
 	if (!f30->gpioled_key_map) {

@@ -242,7 +244,7 @@ static int rmi_f30_map_gpios(struct rmi_function *fn,
 		return -ENOMEM;
 	}
 
-	for (i = 0; i < f30->gpioled_count; i++) {
+	for (i = 0; i < button_count; i++) {
 		if (!rmi_f30_is_valid_button(i, f30->ctrl))
 			continue;
 

-- 
2.7.4

Thanks.

-- 
Dmitry