2 files changed, 67 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff b/Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff
index db197a879580..9cd7c5adeb7e 100644
--- a/Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff
+++ b/Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff
@@ -50,3 +50,12 @@ Description:	Displays the real model of the wheel regardless of any
                 alternate mode the wheel might be switched to.
                 It is a read-only value.
                 This entry is not created for devices that have only one mode.
+
+What:           /sys/bus/hid/drivers/logitech/<dev>/combine_pedals
+Date:           Sep 2016
+KernelVersion:  4.9
+Contact:        Simon Wood <simon@mungewell.org>
+Description:    Controls whether a combined value of accelerator and brake is
+                reported on the Y axis of the controller. Useful for older games
+                which can do not work with separate accelerator/brake axis.
+                Off ('0') by default, enabled by setting '1'.
diff --git a/drivers/hid/hid-lg4ff.c b/drivers/hid/hid-lg4ff.c
index af3a8ec8a746..ca31ce4d2c24 100644
--- a/drivers/hid/hid-lg4ff.c
+++ b/drivers/hid/hid-lg4ff.c
@@ -75,6 +75,7 @@ static void lg4ff_set_range_g25(struct hid_device *hid, u16 range);
 
 struct lg4ff_wheel_data {
         const u32 product_id;
+        u16 combine;
         u16 range;
         const u16 min_range;
         const u16 max_range;
@@ -345,6 +346,7 @@ static void lg4ff_init_wheel_data(struct lg4ff_wheel_data * const wdata, const s
         {
                 struct lg4ff_wheel_data t_wdata =  { .product_id = wheel->product_id,
                                                      .real_product_id = real_product_id,
+                                                     .combine = 0,
                                                      .min_range = wheel->min_range,
                                                      .max_range = wheel->max_range,
                                                      .set_range = wheel->set_range,
@@ -885,6 +887,58 @@ static ssize_t lg4ff_alternate_modes_store(struct device *dev, struct device_att
 }
 static DEVICE_ATTR(alternate_modes, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH, lg4ff_alternate_modes_show, lg4ff_alternate_modes_store);
 
+static ssize_t lg4ff_combine_show(struct device *dev, struct device_attribute *attr,
+                                char *buf)
+{
+        struct hid_device *hid = to_hid_device(dev);
+        struct lg4ff_device_entry *entry;
+        struct lg_drv_data *drv_data;
+        size_t count;
+
+        drv_data = hid_get_drvdata(hid);
+        if (!drv_data) {
+                hid_err(hid, "Private driver data not found!\n");
+                return 0;
+        }
+
+        entry = drv_data->device_props;
+        if (!entry) {
+                hid_err(hid, "Device properties not found!\n");
+                return 0;
+        }
+
+        count = scnprintf(buf, PAGE_SIZE, "%u\n", entry->wdata.combine);
+        return count;
+}
+
+static ssize_t lg4ff_combine_store(struct device *dev, struct device_attribute *attr,
+                                 const char *buf, size_t count)
+{
+        struct hid_device *hid = to_hid_device(dev);
+        struct lg4ff_device_entry *entry;
+        struct lg_drv_data *drv_data;
+        u16 combine = simple_strtoul(buf, NULL, 10);
+
+        drv_data = hid_get_drvdata(hid);
+        if (!drv_data) {
+                hid_err(hid, "Private driver data not found!\n");
+                return -EINVAL;
+        }
+
+        entry = drv_data->device_props;
+        if (!entry) {
+                hid_err(hid, "Device properties not found!\n");
+                return -EINVAL;
+        }
+
+        if (combine > 1)
+                combine = 1;
+
+        entry->wdata.combine = combine;
+        return count;
+}
+static DEVICE_ATTR(combine_pedals, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH, lg4ff_combine_show, lg4ff_combine_store);
+
 /* Export the currently set range of the wheel */
 static ssize_t lg4ff_range_show(struct device *dev, struct device_attribute *attr,
                                 char *buf)
@@ -1259,6 +1313,9 @@ int lg4ff_init(struct hid_device *hid)
         }
 
         /* Create sysfs interface */
+        error = device_create_file(&hid->dev, &dev_attr_combine_pedals);
+        if (error)
+                hid_warn(hid, "Unable to create sysfs interface for \"combine\", errno %d\n", error);
         error = device_create_file(&hid->dev, &dev_attr_range);
         if (error)
                 hid_warn(hid, "Unable to create sysfs interface for \"range\", errno %d\n", error);
@@ -1358,6 +1415,7 @@ int lg4ff_deinit(struct hid_device *hid)
                 device_remove_file(&hid->dev, &dev_attr_alternate_modes);
         }
 
+        device_remove_file(&hid->dev, &dev_attr_combine_pedals);
         device_remove_file(&hid->dev, &dev_attr_range);
 #ifdef CONFIG_LEDS_CLASS
         {