HID: core: implement generic .request()

.request() can be emulated through .raw_request()
we can implement this emulation in hid-core, and make .request
not mandatory for transport layer drivers.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 48 insertions, 2 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 026ab0fc06f7..b6ae69711d2a 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1248,6 +1248,11 @@ void hid_output_report(struct hid_report *report, __u8 *data)
 }
 EXPORT_SYMBOL_GPL(hid_output_report);
 
+static int hid_report_len(struct hid_report *report)
+{
+        return ((report->size - 1) >> 3) + 1 + (report->id > 0) + 7;
+}
+
 /*
  * Allocator for buffer that is going to be passed to hid_output_report()
  */
@@ -1258,7 +1263,7 @@ u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
          * of implement() working on 8 byte chunks
          */
 
-        int len = ((report->size - 1) >> 3) + 1 + (report->id > 0) + 7;
+        int len = hid_report_len(report);
 
         return kmalloc(len, flags);
 }
@@ -1314,6 +1319,44 @@ static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
         return report;
 }
 
+/*
+ * Implement a generic .request() callback, using .raw_request()
+ * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
+ */
+void __hid_request(struct hid_device *hid, struct hid_report *report,
+                int reqtype)
+{
+        char *buf;
+        int ret;
+        int len;
+
+        if (!hid->ll_driver->raw_request)
+                return;
+
+        buf = hid_alloc_report_buf(report, GFP_KERNEL);
+        if (!buf)
+                return;
+
+        len = hid_report_len(report);
+
+        if (reqtype == HID_REQ_SET_REPORT)
+                hid_output_report(report, buf);
+
+        ret = hid->ll_driver->raw_request(hid, report->id, buf, len,
+                                          report->type, reqtype);
+        if (ret < 0) {
+                dbg_hid("unable to complete request: %d\n", ret);
+                goto out;
+        }
+
+        if (reqtype == HID_REQ_GET_REPORT)
+                hid_input_report(hid, report->type, buf, ret, 0);
+
+out:
+        kfree(buf);
+}
+EXPORT_SYMBOL_GPL(__hid_request);
+
 int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
                 int interrupt)
 {
diff --git a/include/linux/hid.h b/include/linux/hid.h
index a837ede65ec6..09fbbd7fb784 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -753,6 +753,7 @@ struct hid_field *hidinput_get_led_field(struct hid_device *hid);
 unsigned int hidinput_count_leds(struct hid_device *hid);
 __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code);
 void hid_output_report(struct hid_report *report, __u8 *data);
+void __hid_request(struct hid_device *hid, struct hid_report *rep, int reqtype);
 u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags);
 struct hid_device *hid_allocate_device(void);
 struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id);
@@ -965,7 +966,9 @@ static inline void hid_hw_request(struct hid_device *hdev,
                                   struct hid_report *report, int reqtype)
 {
         if (hdev->ll_driver->request)
-                hdev->ll_driver->request(hdev, report, reqtype);
+                return hdev->ll_driver->request(hdev, report, reqtype);
+
+        __hid_request(hdev, report, reqtype);
 }
 
 /**