Exporting the hardware type makes it possible for userspace applications
to know what to expect from the hardware.

This makes it possible to write more user-friendly userspace apps.

Note that the size of sysfs_groups[] in struct rc_dev is not changed
by this patch because it was already large enough for one more group.

Signed-off-by: David Härdeman <da...@hardeman.nu>
---
 drivers/media/rc/rc-main.c |   43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index 85f95441b85b..e0f9b322ab02 100644
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -1294,6 +1294,38 @@ static ssize_t store_protocols(struct device *device,
 }
 
 /**
+ * show_hwtype() - shows the hardware type in sysfs
+ * @device:    the &struct device descriptor
+ * @attr:      the &struct device_attribute
+ * @buf:       a pointer to the output buffer
+ *
+ * This callback function is used to get the hardware type of an rc device.
+ * It is triggered by reading /sys/class/rc/rc?/hwtype.
+ *
+ * Return: the number of bytes read or a negative error code.
+ */
+static ssize_t show_hwtype(struct device *device,
+                          struct device_attribute *attr,
+                          char *buf)
+{
+       struct rc_dev *dev = to_rc_dev(device);
+
+       switch (dev->driver_type) {
+       case RC_DRIVER_SCANCODE:
+               return sprintf(buf, "scancode\n");
+       case RC_DRIVER_IR_RAW_TX:
+               return sprintf(buf, "ir-tx\n");
+       case RC_DRIVER_IR_RAW:
+               if (dev->tx_ir)
+                       return sprintf(buf, "ir-tx-rx\n");
+               else
+                       return sprintf(buf, "ir-rx\n");
+       default:
+               return sprintf(buf, "<unknown>\n");
+       }
+}
+
+/**
  * show_filter() - shows the current scancode filter value or mask
  * @device:    the device descriptor
  * @attr:      the device attribute struct
@@ -1613,6 +1645,7 @@ static int rc_dev_uevent(struct device *device, struct 
kobj_uevent_env *env)
  * Static device attribute struct with the sysfs attributes for IR's
  */
 static DEVICE_ATTR(protocols, 0644, show_protocols, store_protocols);
+static DEVICE_ATTR(hwtype, 0444, show_hwtype, NULL);
 static DEVICE_ATTR(wakeup_protocols, 0644, show_wakeup_protocols,
                   store_wakeup_protocols);
 static RC_FILTER_ATTR(filter, S_IRUGO|S_IWUSR,
@@ -1633,6 +1666,15 @@ static struct attribute_group rc_dev_protocol_attr_grp = 
{
        .attrs  = rc_dev_protocol_attrs,
 };
 
+static struct attribute *rc_dev_hwtype_attrs[] = {
+       &dev_attr_hwtype.attr,
+       NULL,
+};
+
+static struct attribute_group rc_dev_hwtype_attr_grp = {
+       .attrs = rc_dev_hwtype_attrs,
+};
+
 static struct attribute *rc_dev_filter_attrs[] = {
        &dev_attr_filter.attr.attr,
        &dev_attr_filter_mask.attr.attr,
@@ -1863,6 +1905,7 @@ int rc_register_device(struct rc_dev *dev)
                dev->sysfs_groups[attr++] = &rc_dev_filter_attr_grp;
        if (dev->s_wakeup_filter)
                dev->sysfs_groups[attr++] = &rc_dev_wakeup_filter_attr_grp;
+       dev->sysfs_groups[attr++] = &rc_dev_hwtype_attr_grp;
        dev->sysfs_groups[attr++] = NULL;
 
        if (dev->driver_type != RC_DRIVER_IR_RAW_TX) {

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