usb/misc/appledisplay.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Apple Cinema Display driver
0004  *
0005  * Copyright (C) 2006  Michael Hanselmann (linux-kernel@hansmi.ch)
0006  *
0007  * Thanks to Caskey L. Dickson for his work with acdctl.
0008  */
0009
0010 #include <linux/kernel.h>
0011 #include <linux/errno.h>
0012 #include <linux/init.h>
0013 #include <linux/module.h>
0014 #include <linux/slab.h>
0015 #include <linux/usb.h>
0016 #include <linux/backlight.h>
0017 #include <linux/timer.h>
0018 #include <linux/workqueue.h>
0019 #include <linux/atomic.h>
0020
0021 #define APPLE_VENDOR_ID     0x05AC
0022
0023 #define USB_REQ_GET_REPORT  0x01
0024 #define USB_REQ_SET_REPORT  0x09
0025
0026 #define ACD_USB_TIMEOUT     250
0027
0028 #define ACD_USB_EDID        0x0302
0029 #define ACD_USB_BRIGHTNESS  0x0310
0030
0031 #define ACD_BTN_NONE        0
0032 #define ACD_BTN_BRIGHT_UP   3
0033 #define ACD_BTN_BRIGHT_DOWN 4
0034
0035 #define ACD_URB_BUFFER_LEN  2
0036 #define ACD_MSG_BUFFER_LEN  2
0037
0038 #define APPLEDISPLAY_DEVICE(prod)               \
0039     .match_flags = USB_DEVICE_ID_MATCH_DEVICE |     \
0040                USB_DEVICE_ID_MATCH_INT_CLASS |      \
0041                USB_DEVICE_ID_MATCH_INT_PROTOCOL,    \
0042     .idVendor = APPLE_VENDOR_ID,                \
0043     .idProduct = (prod),                    \
0044     .bInterfaceClass = USB_CLASS_HID,           \
0045     .bInterfaceProtocol = 0x00
0046
0047 /* table of devices that work with this driver */
0048 static const struct usb_device_id appledisplay_table[] = {
0049     { APPLEDISPLAY_DEVICE(0x9218) },
0050     { APPLEDISPLAY_DEVICE(0x9219) },
0051     { APPLEDISPLAY_DEVICE(0x921c) },
0052     { APPLEDISPLAY_DEVICE(0x921d) },
0053     { APPLEDISPLAY_DEVICE(0x9222) },
0054     { APPLEDISPLAY_DEVICE(0x9226) },
0055     { APPLEDISPLAY_DEVICE(0x9236) },
0056
0057     /* Terminating entry */
0058     { }
0059 };
0060 MODULE_DEVICE_TABLE(usb, appledisplay_table);
0061
0062 /* Structure to hold all of our device specific stuff */
0063 struct appledisplay {
0064     struct usb_device *udev;    /* usb device */
0065     struct urb *urb;        /* usb request block */
0066     struct backlight_device *bd;    /* backlight device */
0067     u8 *urbdata;            /* interrupt URB data buffer */
0068     u8 *msgdata;            /* control message data buffer */
0069
0070     struct delayed_work work;
0071     int button_pressed;
0072     struct mutex sysfslock;     /* concurrent read and write */
0073 };
0074
0075 static atomic_t count_displays = ATOMIC_INIT(0);
0076
0077 static void appledisplay_complete(struct urb *urb)
0078 {
0079     struct appledisplay *pdata = urb->context;
0080     struct device *dev = &pdata->udev->dev;
0081     int status = urb->status;
0082     int retval;
0083
0084     switch (status) {
0085     case 0:
0086         /* success */
0087         break;
0088     case -EOVERFLOW:
0089         dev_err(dev,
0090             "OVERFLOW with data length %d, actual length is %d\n",
0091             ACD_URB_BUFFER_LEN, pdata->urb->actual_length);
0092         fallthrough;
0093     case -ECONNRESET:
0094     case -ENOENT:
0095     case -ESHUTDOWN:
0096         /* This urb is terminated, clean up */
0097         dev_dbg(dev, "%s - urb shuttingdown with status: %d\n",
0098             __func__, status);
0099         return;
0100     default:
0101         dev_dbg(dev, "%s - nonzero urb status received: %d\n",
0102             __func__, status);
0103         goto exit;
0104     }
0105
0106     switch(pdata->urbdata[1]) {
0107     case ACD_BTN_BRIGHT_UP:
0108     case ACD_BTN_BRIGHT_DOWN:
0109         pdata->button_pressed = 1;
0110         schedule_delayed_work(&pdata->work, 0);
0111         break;
0112     case ACD_BTN_NONE:
0113     default:
0114         pdata->button_pressed = 0;
0115         break;
0116     }
0117
0118 exit:
0119     retval = usb_submit_urb(pdata->urb, GFP_ATOMIC);
0120     if (retval) {
0121         dev_err(dev, "%s - usb_submit_urb failed with result %d\n",
0122             __func__, retval);
0123     }
0124 }
0125
0126 static int appledisplay_bl_update_status(struct backlight_device *bd)
0127 {
0128     struct appledisplay *pdata = bl_get_data(bd);
0129     int retval;
0130
0131     mutex_lock(&pdata->sysfslock);
0132     pdata->msgdata[0] = 0x10;
0133     pdata->msgdata[1] = bd->props.brightness;
0134
0135     retval = usb_control_msg(
0136         pdata->udev,
0137         usb_sndctrlpipe(pdata->udev, 0),
0138         USB_REQ_SET_REPORT,
0139         USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
0140         ACD_USB_BRIGHTNESS,
0141         0,
0142         pdata->msgdata, 2,
0143         ACD_USB_TIMEOUT);
0144     mutex_unlock(&pdata->sysfslock);
0145
0146     if (retval < 0)
0147         return retval;
0148     else
0149         return 0;
0150 }
0151
0152 static int appledisplay_bl_get_brightness(struct backlight_device *bd)
0153 {
0154     struct appledisplay *pdata = bl_get_data(bd);
0155     int retval, brightness;
0156
0157     mutex_lock(&pdata->sysfslock);
0158     retval = usb_control_msg(
0159         pdata->udev,
0160         usb_rcvctrlpipe(pdata->udev, 0),
0161         USB_REQ_GET_REPORT,
0162         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
0163         ACD_USB_BRIGHTNESS,
0164         0,
0165         pdata->msgdata, 2,
0166         ACD_USB_TIMEOUT);
0167     if (retval < 2) {
0168         if (retval >= 0)
0169             retval = -EMSGSIZE;
0170     } else {
0171         brightness = pdata->msgdata[1];
0172     }
0173     mutex_unlock(&pdata->sysfslock);
0174
0175     if (retval < 0)
0176         return retval;
0177     else
0178         return brightness;
0179 }
0180
0181 static const struct backlight_ops appledisplay_bl_data = {
0182     .get_brightness = appledisplay_bl_get_brightness,
0183     .update_status  = appledisplay_bl_update_status,
0184 };
0185
0186 static void appledisplay_work(struct work_struct *work)
0187 {
0188     struct appledisplay *pdata =
0189         container_of(work, struct appledisplay, work.work);
0190     int retval;
0191
0192     retval = appledisplay_bl_get_brightness(pdata->bd);
0193     if (retval >= 0)
0194         pdata->bd->props.brightness = retval;
0195
0196     /* Poll again in about 125ms if there's still a button pressed */
0197     if (pdata->button_pressed)
0198         schedule_delayed_work(&pdata->work, HZ / 8);
0199 }
0200
0201 static int appledisplay_probe(struct usb_interface *iface,
0202     const struct usb_device_id *id)
0203 {
0204     struct backlight_properties props;
0205     struct appledisplay *pdata;
0206     struct usb_device *udev = interface_to_usbdev(iface);
0207     struct usb_endpoint_descriptor *endpoint;
0208     int int_in_endpointAddr = 0;
0209     int retval, brightness;
0210     char bl_name[20];
0211
0212     /* set up the endpoint information */
0213     /* use only the first interrupt-in endpoint */
0214     retval = usb_find_int_in_endpoint(iface->cur_altsetting, &endpoint);
0215     if (retval) {
0216         dev_err(&iface->dev, "Could not find int-in endpoint\n");
0217         return retval;
0218     }
0219
0220     int_in_endpointAddr = endpoint->bEndpointAddress;
0221
0222     /* allocate memory for our device state and initialize it */
0223     pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL);
0224     if (!pdata) {
0225         retval = -ENOMEM;
0226         goto error;
0227     }
0228
0229     pdata->udev = udev;
0230
0231     INIT_DELAYED_WORK(&pdata->work, appledisplay_work);
0232     mutex_init(&pdata->sysfslock);
0233
0234     /* Allocate buffer for control messages */
0235     pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL);
0236     if (!pdata->msgdata) {
0237         retval = -ENOMEM;
0238         goto error;
0239     }
0240
0241     /* Allocate interrupt URB */
0242     pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
0243     if (!pdata->urb) {
0244         retval = -ENOMEM;
0245         goto error;
0246     }
0247
0248     /* Allocate buffer for interrupt data */
0249     pdata->urbdata = usb_alloc_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
0250         GFP_KERNEL, &pdata->urb->transfer_dma);
0251     if (!pdata->urbdata) {
0252         retval = -ENOMEM;
0253         dev_err(&iface->dev, "Allocating URB buffer failed\n");
0254         goto error;
0255     }
0256
0257     /* Configure interrupt URB */
0258     usb_fill_int_urb(pdata->urb, udev,
0259         usb_rcvintpipe(udev, int_in_endpointAddr),
0260         pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
0261         pdata, 1);
0262     pdata->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
0263     if (usb_submit_urb(pdata->urb, GFP_KERNEL)) {
0264         retval = -EIO;
0265         dev_err(&iface->dev, "Submitting URB failed\n");
0266         goto error;
0267     }
0268
0269     /* Register backlight device */
0270     snprintf(bl_name, sizeof(bl_name), "appledisplay%d",
0271         atomic_inc_return(&count_displays) - 1);
0272     memset(&props, 0, sizeof(struct backlight_properties));
0273     props.type = BACKLIGHT_RAW;
0274     props.max_brightness = 0xff;
0275     pdata->bd = backlight_device_register(bl_name, NULL, pdata,
0276                           &appledisplay_bl_data, &props);
0277     if (IS_ERR(pdata->bd)) {
0278         dev_err(&iface->dev, "Backlight registration failed\n");
0279         retval = PTR_ERR(pdata->bd);
0280         goto error;
0281     }
0282
0283     /* Try to get brightness */
0284     brightness = appledisplay_bl_get_brightness(pdata->bd);
0285
0286     if (brightness < 0) {
0287         retval = brightness;
0288         dev_err(&iface->dev,
0289             "Error while getting initial brightness: %d\n", retval);
0290         goto error;
0291     }
0292
0293     /* Set brightness in backlight device */
0294     pdata->bd->props.brightness = brightness;
0295
0296     /* save our data pointer in the interface device */
0297     usb_set_intfdata(iface, pdata);
0298
0299     printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");
0300
0301     return 0;
0302
0303 error:
0304     if (pdata) {
0305         if (pdata->urb) {
0306             usb_kill_urb(pdata->urb);
0307             cancel_delayed_work_sync(&pdata->work);
0308             usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
0309                     pdata->urbdata, pdata->urb->transfer_dma);
0310             usb_free_urb(pdata->urb);
0311         }
0312         if (!IS_ERR(pdata->bd))
0313             backlight_device_unregister(pdata->bd);
0314         kfree(pdata->msgdata);
0315     }
0316     usb_set_intfdata(iface, NULL);
0317     kfree(pdata);
0318     return retval;
0319 }
0320
0321 static void appledisplay_disconnect(struct usb_interface *iface)
0322 {
0323     struct appledisplay *pdata = usb_get_intfdata(iface);
0324
0325     if (pdata) {
0326         usb_kill_urb(pdata->urb);
0327         cancel_delayed_work_sync(&pdata->work);
0328         backlight_device_unregister(pdata->bd);
0329         usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
0330             pdata->urbdata, pdata->urb->transfer_dma);
0331         usb_free_urb(pdata->urb);
0332         kfree(pdata->msgdata);
0333         kfree(pdata);
0334     }
0335
0336     printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n");
0337 }
0338
0339 static struct usb_driver appledisplay_driver = {
0340     .name       = "appledisplay",
0341     .probe      = appledisplay_probe,
0342     .disconnect = appledisplay_disconnect,
0343     .id_table   = appledisplay_table,
0344 };
0345 module_usb_driver(appledisplay_driver);
0346
0347 MODULE_AUTHOR("Michael Hanselmann");
0348 MODULE_DESCRIPTION("Apple Cinema Display driver");
0349 MODULE_LICENSE("GPL");