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Subject: Re: [PATCH v9 05/11] Input: wacom_i2c - Add support for distance and
 tilt x/y
To:     Alistair Francis <alistair@alistair23.me>,
        dmitry.torokhov@gmail.com, linux-input@vger.kernel.org,
        linux-imx@nxp.com, kernel@pengutronix.de, pinglinux@gmail.com,
        tatsunosuke.tobita@wacom.com, junkpainting@gmail.com,
        ping.cheng@wacom.com
Cc:     alistair23@gmail.com, robh+dt@kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
References: <20210818154935.1154-1-alistair@alistair23.me>
 <20210818154935.1154-6-alistair@alistair23.me>
From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
Message-ID: <e3d7b9be-cf0e-7074-3e49-45dbff27ce8d@pengutronix.de>
Date:   Mon, 23 Aug 2021 09:06:59 +0200
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On 18.08.21 17:49, Alistair Francis wrote:
> Add support for the distance and tilt x/y.
> 
> This is based on the out of tree rM2 driver.
> 
> Signed-off-by: Alistair Francis <alistair@alistair23.me>
> ---
>  drivers/input/touchscreen/wacom_i2c.c | 35 +++++++++++++++++++++++++--
>  1 file changed, 33 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/wacom_i2c.c b/drivers/input/touchscreen/wacom_i2c.c
> index 28255c77d426..4d0c19fbada4 100644
> --- a/drivers/input/touchscreen/wacom_i2c.c
> +++ b/drivers/input/touchscreen/wacom_i2c.c

> +	/* Signed */
> +	tilt_x = le16_to_cpup((__le16 *)&data[11]);
> +	tilt_y = le16_to_cpup((__le16 *)&data[13]);
> +
> +	distance = le16_to_cpup((__le16 *)&data[15]);

Use get_unaligned_u16 for all three. The existing code doesn't need to do this,
because with the current struct layout, the array is suitable aligned
for 2 byte accesses. You are accessing data at odd indices though, so you
need to use an unaligned accessor.

Cheers,
Ahmad

> +
>  	if (!wac_i2c->prox)
>  		wac_i2c->tool = (data[3] & 0x0c) ?
>  			BTN_TOOL_RUBBER : BTN_TOOL_PEN;
> @@ -127,6 +151,9 @@ static irqreturn_t wacom_i2c_irq(int irq, void *dev_id)
>  	input_report_abs(input, ABS_X, x);
>  	input_report_abs(input, ABS_Y, y);
>  	input_report_abs(input, ABS_PRESSURE, pressure);
> +	input_report_abs(input, ABS_DISTANCE, distance);
> +	input_report_abs(input, ABS_TILT_X, tilt_x);
> +	input_report_abs(input, ABS_TILT_Y, tilt_y);
>  	input_sync(input);
>  
>  out:
> @@ -202,7 +229,11 @@ static int wacom_i2c_probe(struct i2c_client *client,
>  	input_set_abs_params(input, ABS_Y, 0, features->y_max, 0, 0);
>  	input_set_abs_params(input, ABS_PRESSURE,
>  			     0, features->pressure_max, 0, 0);
> -
> +	input_set_abs_params(input, ABS_DISTANCE, 0, features->distance_max, 0, 0);
> +	input_set_abs_params(input, ABS_TILT_X, -features->tilt_x_max,
> +			     features->tilt_x_max, 0, 0);
> +	input_set_abs_params(input, ABS_TILT_Y, -features->tilt_y_max,
> +			     features->tilt_y_max, 0, 0);
>  	input_set_drvdata(input, wac_i2c);
>  
>  	error = devm_request_threaded_irq(dev, client->irq, NULL, wacom_i2c_irq,
> 


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