Patch "Input: mpr121 - handle multiple bits change of status register" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    Input: mpr121 - handle multiple bits change of status register

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     input-mpr121-handle-multiple-bits-change-of-status-register.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Nov  9 18:22:51 CET 2017
From: Akinobu Mita <akinobu.mita@gmail.com>
Date: Sun, 15 Jan 2017 14:44:30 -0800
Subject: Input: mpr121 - handle multiple bits change of status register

From: Akinobu Mita <akinobu.mita@gmail.com>


[ Upstream commit 08fea55e37f58371bffc5336a59e55d1f155955a ]

This driver reports input events on their interrupts which are triggered
by the sensor's status register changes.  But only single bit change is
reported in the interrupt handler.  So if there are multiple bits are
changed at almost the same time, other press or release events are ignored.

This fixes it by detecting all changed bits in the status register.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/input/keyboard/mpr121_touchkey.c |   23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

--- a/drivers/input/keyboard/mpr121_touchkey.c
+++ b/drivers/input/keyboard/mpr121_touchkey.c
@@ -87,7 +87,8 @@ static irqreturn_t mpr_touchkey_interrup
 	struct mpr121_touchkey *mpr121 = dev_id;
 	struct i2c_client *client = mpr121->client;
 	struct input_dev *input = mpr121->input_dev;
-	unsigned int key_num, key_val, pressed;
+	unsigned long bit_changed;
+	unsigned int key_num;
 	int reg;
 
 	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
@@ -105,18 +106,22 @@ static irqreturn_t mpr_touchkey_interrup
 
 	reg &= TOUCH_STATUS_MASK;
 	/* use old press bit to figure out which bit changed */
-	key_num = ffs(reg ^ mpr121->statusbits) - 1;
-	pressed = reg & (1 << key_num);
+	bit_changed = reg ^ mpr121->statusbits;
 	mpr121->statusbits = reg;
+	for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
+		unsigned int key_val, pressed;
 
-	key_val = mpr121->keycodes[key_num];
+		pressed = reg & BIT(key_num);
+		key_val = mpr121->keycodes[key_num];
 
-	input_event(input, EV_MSC, MSC_SCAN, key_num);
-	input_report_key(input, key_val, pressed);
-	input_sync(input);
+		input_event(input, EV_MSC, MSC_SCAN, key_num);
+		input_report_key(input, key_val, pressed);
+
+		dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
+			pressed ? "pressed" : "released");
 
-	dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
-		pressed ? "pressed" : "released");
+	}
+	input_sync(input);
 
 out:
 	return IRQ_HANDLED;


Patches currently in stable-queue which might be from akinobu.mita@gmail.com are

queue-4.4/input-mpr121-set-missing-event-capability.patch
queue-4.4/input-mpr121-handle-multiple-bits-change-of-status-register.patch