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Subject[PATCH] Input: tca8418_keypad: hide gcc-4.9 -Wmaybe-uninitialized warning
Date
Older versions of gcc warn about the tca8418_irq_handler function
as they can't keep track of the variable assignment inside of the
loop when using the -Wmaybe-unintialized flag:

drivers/input/keyboard/tca8418_keypad.c: In function ‘tca8418_irq_handler’:
drivers/input/keyboard/tca8418_keypad.c:172:9: error: ‘reg’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/input/keyboard/tca8418_keypad.c:165:5: note: ‘reg’ was declared here

This is fixed in gcc-6, but it's possible to rearrange the code
in a way that avoids the warning on older compilers as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/input/keyboard/tca8418_keypad.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/input/keyboard/tca8418_keypad.c b/drivers/input/keyboard/tca8418_keypad.c
index 9002298698fc..3048ef3e3e16 100644
--- a/drivers/input/keyboard/tca8418_keypad.c
+++ b/drivers/input/keyboard/tca8418_keypad.c
@@ -164,11 +164,18 @@ static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
int error, col, row;
u8 reg, state, code;

- /* Initial read of the key event FIFO */
- error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
+ do {
+ error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
+ if (error < 0) {
+ dev_err(&keypad_data->client->dev,
+ "unable to read REG_KEY_EVENT_A\n");
+ break;
+ }
+
+ /* Assume that key code 0 signifies empty FIFO */
+ if (reg <= 0)
+ break;

- /* Assume that key code 0 signifies empty FIFO */
- while (error >= 0 && reg > 0) {
state = reg & KEY_EVENT_VALUE;
code = reg & KEY_EVENT_CODE;

@@ -184,11 +191,7 @@ static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)

/* Read for next loop */
error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
- }
-
- if (error < 0)
- dev_err(&keypad_data->client->dev,
- "unable to read REG_KEY_EVENT_A\n");
+ } while (1);

input_sync(input);
}
--
2.9.0
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