[PATCH] input: keyboard: imx_sc_key: Only take the valid data from SCU firmware as key state

[PATCH] input: keyboard: imx_sc_key: Only take the valid data from SCU firmware as key state

[Anson Huang]

When reading key state from SCU, the response data from SCU firmware
is 4 bytes due to MU message protocol, but ONLY the first byte is the
key state, other 3 bytes could be some dirty data, so we should ONLY
take the first byte as key state to avoid reporting incorrect state.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
 drivers/input/keyboard/imx_sc_key.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/input/keyboard/imx_sc_key.c b/drivers/input/keyboard/imx_sc_key.c
index 5379952..9f809ae 100644
--- a/drivers/input/keyboard/imx_sc_key.c
+++ b/drivers/input/keyboard/imx_sc_key.c
@@ -78,7 +78,13 @@ static void imx_sc_check_for_events(struct work_struct *work)
 		return;
 	}
 
-	state = (bool)msg.state;
+	/*
+	 * The response data from SCU firmware is 4 bytes,
+	 * but ONLY the first byte is the key state, other
+	 * 3 bytes could be some dirty data, so we should
+	 * ONLY take the first byte as key state.
+	 */
+	state = (bool)(msg.state & 0xff);
 
 	if (state ^ priv->keystate) {
 		priv->keystate = state;
-- 
2.7.4


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Re: [PATCH] input: keyboard: imx_sc_key: Only take the valid data from SCU firmware as key state

[Dmitry Torokhov]

On Fri, Dec 13, 2019 at 10:08:29AM +0800, Anson Huang wrote:
> When reading key state from SCU, the response data from SCU firmware
> is 4 bytes due to MU message protocol, but ONLY the first byte is the
> key state, other 3 bytes could be some dirty data, so we should ONLY
> take the first byte as key state to avoid reporting incorrect state.
> 
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>

Applied, thank you.

> ---
>  drivers/input/keyboard/imx_sc_key.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/keyboard/imx_sc_key.c b/drivers/input/keyboard/imx_sc_key.c
> index 5379952..9f809ae 100644
> --- a/drivers/input/keyboard/imx_sc_key.c
> +++ b/drivers/input/keyboard/imx_sc_key.c
> @@ -78,7 +78,13 @@ static void imx_sc_check_for_events(struct work_struct *work)
>  		return;
>  	}
>  
> -	state = (bool)msg.state;
> +	/*
> +	 * The response data from SCU firmware is 4 bytes,
> +	 * but ONLY the first byte is the key state, other
> +	 * 3 bytes could be some dirty data, so we should
> +	 * ONLY take the first byte as key state.
> +	 */
> +	state = (bool)(msg.state & 0xff);
>  
>  	if (state ^ priv->keystate) {
>  		priv->keystate = state;
> -- 
> 2.7.4
> 

-- 
Dmitry

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