HID: elo: add quirks for broken firmware

One firmare version in the devices the driver takes care of is
completely broken and needs periodic pokes from our side. We
implemented this as a periodic delayed queue. The idea of the pokes
was taken from the suse enterprise kernel, in particular from Libor's
"Elo touchscreen firmware M workaround".

I am quoting him here:
  This patch adds periodic polling of the Elo USB touchscreens. Needed
  as a workaround for devices with M-level firmware, otherwise these
  devices are known to misbehave (as reported by Elo developers).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Petr Ostadal <postadal@suse.cz>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Cc: Egbert Eich <eich@suse.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 143 insertions, 1 deletions

diff --git a/drivers/hid/hid-elo.c b/drivers/hid/hid-elo.c
index 56143e011f22..f042a6cf8b18 100644
--- a/drivers/hid/hid-elo.c
+++ b/drivers/hid/hid-elo.c
@@ -11,9 +11,32 @@
 #include <linux/hid.h>
 #include <linux/input.h>
 #include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/workqueue.h>
 
 #include "hid-ids.h"
 
+#define ELO_PERIODIC_READ_INTERVAL      HZ
+#define ELO_SMARTSET_CMD_TIMEOUT        2000 /* msec */
+
+/* Elo SmartSet commands */
+#define ELO_FLUSH_SMARTSET_RESPONSES    0x02 /* Flush all pending smartset responses */
+#define ELO_SEND_SMARTSET_COMMAND       0x05 /* Send a smartset command */
+#define ELO_GET_SMARTSET_RESPONSE       0x06 /* Get a smartset response */
+#define ELO_DIAG                        0x64 /* Diagnostics command */
+#define ELO_SMARTSET_PACKET_SIZE        8
+
+struct elo_priv {
+        struct usb_device *usbdev;
+        struct delayed_work work;
+        unsigned char buffer[ELO_SMARTSET_PACKET_SIZE];
+};
+
+static struct workqueue_struct *wq;
+static bool use_fw_quirk = true;
+module_param(use_fw_quirk, bool, S_IRUGO);
+MODULE_PARM_DESC(use_fw_quirk, "Do periodic pokes for broken M firmwares (default = true)");
+
 static void elo_input_configured(struct hid_device *hdev,
                 struct hid_input *hidinput)
 {
@@ -73,10 +96,108 @@ static int elo_raw_event(struct hid_device *hdev, struct hid_report *report,
         return 0;
 }
 
+static int elo_smartset_send_get(struct usb_device *dev, u8 command,
+                void *data)
+{
+        unsigned int pipe;
+        u8 dir;
+
+        if (command == ELO_SEND_SMARTSET_COMMAND) {
+                pipe = usb_sndctrlpipe(dev, 0);
+                dir = USB_DIR_OUT;
+        } else if (command == ELO_GET_SMARTSET_RESPONSE) {
+                pipe = usb_rcvctrlpipe(dev, 0);
+                dir = USB_DIR_IN;
+        } else
+                return -EINVAL;
+
+        return usb_control_msg(dev, pipe, command,
+                        dir | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                        0, 0, data, ELO_SMARTSET_PACKET_SIZE,
+                        ELO_SMARTSET_CMD_TIMEOUT);
+}
+
+static int elo_flush_smartset_responses(struct usb_device *dev)
+{
+        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+                        ELO_FLUSH_SMARTSET_RESPONSES,
+                        USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                        0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
+}
+
+static void elo_work(struct work_struct *work)
+{
+        struct elo_priv *priv = container_of(work, struct elo_priv, work.work);
+        struct usb_device *dev = priv->usbdev;
+        unsigned char *buffer = priv->buffer;
+        int ret;
+
+        ret = elo_flush_smartset_responses(dev);
+        if (ret < 0) {
+                dev_err(&dev->dev, "initial FLUSH_SMARTSET_RESPONSES failed, error %d\n",
+                                ret);
+                goto fail;
+        }
+
+        /* send Diagnostics command */
+        *buffer = ELO_DIAG;
+        ret = elo_smartset_send_get(dev, ELO_SEND_SMARTSET_COMMAND, buffer);
+        if (ret < 0) {
+                dev_err(&dev->dev, "send Diagnostics Command failed, error %d\n",
+                                ret);
+                goto fail;
+        }
+
+        /* get the result */
+        ret = elo_smartset_send_get(dev, ELO_GET_SMARTSET_RESPONSE, buffer);
+        if (ret < 0) {
+                dev_err(&dev->dev, "get Diagnostics Command response failed, error %d\n",
+                                ret);
+                goto fail;
+        }
+
+        /* read the ack */
+        if (*buffer != 'A') {
+                ret = elo_smartset_send_get(dev, ELO_GET_SMARTSET_RESPONSE,
+                                buffer);
+                if (ret < 0) {
+                        dev_err(&dev->dev, "get acknowledge response failed, error %d\n",
+                                        ret);
+                        goto fail;
+                }
+        }
+
+fail:
+        ret = elo_flush_smartset_responses(dev);
+        if (ret < 0)
+                dev_err(&dev->dev, "final FLUSH_SMARTSET_RESPONSES failed, error %d\n",
+                                ret);
+        queue_delayed_work(wq, &priv->work, ELO_PERIODIC_READ_INTERVAL);
+}
+
+/*
+ * Not all Elo devices need the periodic HID descriptor reads.
+ * Only firmware version M needs this.
+ */
+static bool elo_broken_firmware(struct usb_device *dev)
+{
+        return use_fw_quirk && le16_to_cpu(dev->descriptor.bcdDevice) == 0x10d;
+}
+
 static int elo_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
+        struct elo_priv *priv;
         int ret;
 
+        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+        if (!priv)
+                return -ENOMEM;
+
+        INIT_DELAYED_WORK(&priv->work, elo_work);
+        priv->usbdev = interface_to_usbdev(to_usb_interface(hdev->dev.parent));
+
+        hid_set_drvdata(hdev, priv);
+
         ret = hid_parse(hdev);
         if (ret) {
                 hid_err(hdev, "parse failed\n");
@@ -89,14 +210,24 @@ static int elo_probe(struct hid_device *hdev, const struct hid_device_id *id)
                 goto err_free;
         }
 
+        if (elo_broken_firmware(priv->usbdev)) {
+                hid_info(hdev, "broken firmware found, installing workaround\n");
+                queue_delayed_work(wq, &priv->work, ELO_PERIODIC_READ_INTERVAL);
+        }
+
         return 0;
 err_free:
+        kfree(priv);
         return ret;
 }
 
 static void elo_remove(struct hid_device *hdev)
 {
+        struct elo_priv *priv = hid_get_drvdata(hdev);
+
         hid_hw_stop(hdev);
+        flush_workqueue(wq);
+        kfree(priv);
 }
 
 static const struct hid_device_id elo_devices[] = {
@@ -117,13 +248,24 @@ static struct hid_driver elo_driver = {
 
 static int __init elo_driver_init(void)
 {
-        return hid_register_driver(&elo_driver);
+        int ret;
+
+        wq = create_singlethread_workqueue("elousb");
+        if (!wq)
+                return -ENOMEM;
+
+        ret = hid_register_driver(&elo_driver);
+        if (ret)
+                destroy_workqueue(wq);
+
+        return ret;
 }
 module_init(elo_driver_init);
 
 static void __exit elo_driver_exit(void)
 {
         hid_unregister_driver(&elo_driver);
+        destroy_workqueue(wq);
 }
 module_exit(elo_driver_exit);