Messages in this thread | | | Date | Wed, 29 Mar 2017 10:13:59 +0200 | From | Robin van der Gracht <> | Subject | Re: [PATCH] auxdisplay: ht16k33: use le16_to_cpup() to fetch LE16 data |
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On Wed, 29 Mar 2017 00:42:08 -0700 Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:
> The data read from the device is 3 little-endian words, so let's annotate > them as such and use le16_to_cpu() to convert them to host endianness - it > might turn out to be a bit more performant, and it expresses the conversion > more clearly.
Agreed
> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > --- > drivers/auxdisplay/ht16k33.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c > index f66b45b235b0..61af52a7afd5 100644 > --- a/drivers/auxdisplay/ht16k33.c > +++ b/drivers/auxdisplay/ht16k33.c > @@ -254,18 +254,19 @@ static bool ht16k33_keypad_scan(struct ht16k33_keypad *keypad) > { > const unsigned short *keycodes = keypad->dev->keycode; > u16 new_state[HT16K33_MATRIX_KEYPAD_MAX_COLS]; > - u8 data[HT16K33_MATRIX_KEYPAD_MAX_COLS * 2]; > + __le16 data[HT16K33_MATRIX_KEYPAD_MAX_COLS]; > unsigned long bits_changed; > int row, col, code; > bool pressed = false; > > - if (i2c_smbus_read_i2c_block_data(keypad->client, 0x40, 6, data) != 6) { > + if (i2c_smbus_read_i2c_block_data(keypad->client, 0x40, > + sizeof(data), (u8 *)data) != 6) {
Why use sizeof(data) for length but check against the hardcoded 6?
> dev_err(&keypad->client->dev, "Failed to read key data\n"); > return false; > } > > for (col = 0; col < keypad->cols; col++) { > - new_state[col] = (data[col * 2 + 1] << 8) | data[col * 2]; > + new_state[col] = le16_to_cpu(data[col]);
nice!
> if (new_state[col]) > pressed = true; > bits_changed = keypad->last_key_state[col] ^ new_state[col];
Robin
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