Query the resolution from the touchpad and report it to userspace
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v2:
-Simplify elan_convert_res() and add a comment explaining what it does
---
drivers/hid/hid-elan.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/hid/hid-elan.c b/drivers/hid/hid-elan.c
index d696b57f1ccd..6969fb5344a5 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 +99,15 @@ static int elan_get_device_param(struct hid_device *hdev,
return 0;
}
+static unsigned int elan_convert_res(char val)
+{
+ /*
+ * (value from firmware) * 10 + 790 = dpi
+ * dpi * 10 / 254 = dots/mm
+ */
+ return (val * 10 + 790) * 10 / 254;
+}
+
static int elan_get_device_params(struct hid_device *hdev)
{
struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
@@ -119,6 +130,13 @@ 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 +184,9 @@ 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",
--
2.17.1
--
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