HID: elan: Query resolution from the touchpad

Query the resolution from the touchpad and report it to userspace

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-elan.c b/drivers/hid/hid-elan.c
index d696b57f1ccdd64dde62b6cdc6d8b9db46501c81..6969fb5344a58c76565c2e4e06b48c3b9649c1be 100644 (file)
--- 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",