Hi Hans,
On Fri, Jun 1, 2018 at 3:05 PM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> Query the resolution from the touchpad and report it to userspace
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> drivers/hid/hid-elan.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/hid/hid-elan.c b/drivers/hid/hid-elan.c
> index d696b57f1ccd..4791c22a3d37 100644
> --- a/drivers/hid/hid-elan.c
> +++ b/drivers/hid/hid-elan.c
> @@ -43,6 +43,8 @@ struct elan_drvdata {
> u8 mute_led_state;
> u16 max_x;
> u16 max_y;
> + u16 res_x;
> + u16 res_y;
> };
>
> static int is_not_elan_touchpad(struct hid_device *hdev)
> @@ -97,6 +99,20 @@ static int elan_get_device_param(struct hid_device *hdev,
> return 0;
> }
>
> +static unsigned int elan_convert_res(char val)
> +{
> + int res;
> +
> + if (val & 0x80) {
> + val = ~val + 1;
> + res = (790 - val * 10) * 10 / 254;
> + } else {
> + res = (val * 10 + 790) * 10 / 254;
Could you explain a little bit those computations?
I have a feeling there is a inch to/from mm involved, but better not
have random values inserted in the code.
Cheers,
Benjamin
> + }
> +
> + return res;
> +}
> +
> static int elan_get_device_params(struct hid_device *hdev)
> {
> struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
> @@ -119,6 +135,13 @@ static int elan_get_device_params(struct hid_device *hdev)
>
> drvdata->max_y = (dmabuf[4] << 8) | dmabuf[3];
>
> + ret = elan_get_device_param(hdev, dmabuf, ELAN_PARAM_RES);
> + if (ret)
> + goto err;
> +
> + drvdata->res_x = elan_convert_res(dmabuf[3]);
> + drvdata->res_y = elan_convert_res(dmabuf[4]);
> +
> err:
> kfree(dmabuf);
> return ret;
> @@ -166,6 +189,9 @@ static int elan_input_configured(struct hid_device *hdev, struct hid_input *hi)
> return ret;
> }
>
> + input_abs_set_res(input, ABS_X, drvdata->res_x);
> + input_abs_set_res(input, ABS_Y, drvdata->res_y);
> +
> ret = input_register_device(input);
> if (ret) {
> hid_err(hdev, "Failed to register elan input device: %d\n",
> --
> 2.17.0
>
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