HID: add framebuffer support to PicoLCD device

Add framebuffer support to PicoLCD device with use of deferred-io.

Only changed areas of framebuffer get sent to device in order to
save USB bandwidth and especially resources on PicoLCD device or
allow higher refresh rate for a small area. Changed tiles are
determined while updating shadow framebuffer.

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

3 files changed, 573 insertions, 2 deletions

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 138ba6a277ee..a813ea9c792d 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -265,6 +265,11 @@ config HID_PETALYNX
 config HID_PICOLCD
         tristate "PicoLCD (graphic version)"
         depends on USB_HID
+        select FB_DEFERRED_IO if FB
+        select FB_SYS_FILLRECT if FB
+        select FB_SYS_COPYAREA if FB
+        select FB_SYS_IMAGEBLIT if FB
+        select FB_SYS_FOPS if FB
         ---help---
           This provides support for Minibox PicoLCD devices, currently
           only the graphical ones are supported.
@@ -272,8 +277,8 @@ config HID_PICOLCD
           This includes support for the following device features:
           - Keypad
           - Switching between Firmware and Flash mode
-          Features that are not (yet) supported:
           - Framebuffer for monochrome 256x64 display
+          Features that are not (yet) supported:
           - Backlight control
           - Contrast control
           - IR
diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index c7855f388898..e14464789e10 100644
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -24,6 +24,9 @@
 #include "usbhid/usbhid.h"
 #include <linux/usb.h>
 
+#include <linux/fb.h>
+#include <linux/vmalloc.h>
+
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
 
@@ -69,6 +72,59 @@
 #define REPORT_HOOK_VERSION    0xf7 /* LCD: IN[2], OUT[1]   */
 #define REPORT_EXIT_FLASHER    0xff /*                      Bootloader: OUT[2]         */
 
+#if defined(CONFIG_FB) || defined(CONFIG_FB_MODULE)
+/* Framebuffer
+ *
+ * The PicoLCD use a Topway LCD module of 256x64 pixel
+ * This display area is tiled over 4 controllers with 8 tiles
+ * each. Each tile has 8x64 pixel, each data byte representing
+ * a 1-bit wide vertical line of the tile.
+ *
+ * The display can be updated at a tile granularity.
+ *
+ *       Chip 1           Chip 2           Chip 3           Chip 4
+ * +----------------+----------------+----------------+----------------+
+ * |     Tile 1     |     Tile 1     |     Tile 1     |     Tile 1     |
+ * +----------------+----------------+----------------+----------------+
+ * |     Tile 2     |     Tile 2     |     Tile 2     |     Tile 2     |
+ * +----------------+----------------+----------------+----------------+
+ *                                  ...
+ * +----------------+----------------+----------------+----------------+
+ * |     Tile 8     |     Tile 8     |     Tile 8     |     Tile 8     |
+ * +----------------+----------------+----------------+----------------+
+ */
+#define PICOLCDFB_NAME "picolcdfb"
+#define PICOLCDFB_WIDTH (256)
+#define PICOLCDFB_HEIGHT (64)
+#define PICOLCDFB_SIZE (PICOLCDFB_WIDTH * PICOLCDFB_HEIGHT / 8)
+
+#define PICOLCDFB_UPDATE_RATE_LIMIT   10
+#define PICOLCDFB_UPDATE_RATE_DEFAULT  2
+
+/* Framebuffer visual structures */
+static const struct fb_fix_screeninfo picolcdfb_fix = {
+        .id          = PICOLCDFB_NAME,
+        .type        = FB_TYPE_PACKED_PIXELS,
+        .visual      = FB_VISUAL_MONO01,
+        .xpanstep    = 0,
+        .ypanstep    = 0,
+        .ywrapstep   = 0,
+        .line_length = PICOLCDFB_WIDTH / 8,
+        .accel       = FB_ACCEL_NONE,
+};
+
+static const struct fb_var_screeninfo picolcdfb_var = {
+        .xres           = PICOLCDFB_WIDTH,
+        .yres           = PICOLCDFB_HEIGHT,
+        .xres_virtual   = PICOLCDFB_WIDTH,
+        .yres_virtual   = PICOLCDFB_HEIGHT,
+        .width          = 103,
+        .height         = 26,
+        .bits_per_pixel = 1,
+        .grayscale      = 1,
+};
+#endif /* CONFIG_FB */
+
 /* Input device
  *
  * The PicoLCD has an IR receiver header, a built-in keypad with 5 keys
@@ -118,6 +174,16 @@ struct picolcd_data {
         struct input_dev *input_cir;
         unsigned short keycode[PICOLCD_KEYS];
 
+#if defined(CONFIG_FB) || defined(CONFIG_FB_MODULE)
+        /* Framebuffer stuff */
+        u8 fb_update_rate;
+        u8 fb_bpp;
+        u8 *fb_vbitmap;         /* local copy of what was sent to PicoLCD */
+        u8 *fb_bitmap;          /* framebuffer */
+        struct fb_info *fb_info;
+        struct fb_deferred_io fb_defio;
+#endif /* CONFIG_FB */
+
         /* Housekeeping stuff */
         spinlock_t lock;
         struct mutex mutex;
@@ -125,6 +191,7 @@ struct picolcd_data {
         int status;
 #define PICOLCD_BOOTLOADER 1
 #define PICOLCD_FAILED 2
+#define PICOLCD_READY_FB 4
 };
 
 
@@ -197,6 +264,486 @@ static struct picolcd_pending *picolcd_send_and_wait(struct hid_device *hdev,
         return work;
 }
 
+#if defined(CONFIG_FB) || defined(CONFIG_FB_MODULE)
+/* Send a given tile to PicoLCD */
+static int picolcd_fb_send_tile(struct hid_device *hdev, int chip, int tile)
+{
+        struct picolcd_data *data = hid_get_drvdata(hdev);
+        struct hid_report *report1 = picolcd_out_report(REPORT_LCD_CMD_DATA, hdev);
+        struct hid_report *report2 = picolcd_out_report(REPORT_LCD_DATA, hdev);
+        unsigned long flags;
+        u8 *tdata;
+        int i;
+
+        if (!report1 || report1->maxfield != 1 || !report2 || report2->maxfield != 1)
+                return -ENODEV;
+
+        spin_lock_irqsave(&data->lock, flags);
+        hid_set_field(report1->field[0],  0, chip << 2);
+        hid_set_field(report1->field[0],  1, 0x02);
+        hid_set_field(report1->field[0],  2, 0x00);
+        hid_set_field(report1->field[0],  3, 0x00);
+        hid_set_field(report1->field[0],  4, 0xb8 | tile);
+        hid_set_field(report1->field[0],  5, 0x00);
+        hid_set_field(report1->field[0],  6, 0x00);
+        hid_set_field(report1->field[0],  7, 0x40);
+        hid_set_field(report1->field[0],  8, 0x00);
+        hid_set_field(report1->field[0],  9, 0x00);
+        hid_set_field(report1->field[0], 10,   32);
+
+        hid_set_field(report2->field[0],  0, (chip << 2) | 0x01);
+        hid_set_field(report2->field[0],  1, 0x00);
+        hid_set_field(report2->field[0],  2, 0x00);
+        hid_set_field(report2->field[0],  3,   32);
+
+        tdata = data->fb_vbitmap + (tile * 4 + chip) * 64;
+        for (i = 0; i < 64; i++)
+                if (i < 32)
+                        hid_set_field(report1->field[0], 11 + i, tdata[i]);
+                else
+                        hid_set_field(report2->field[0], 4 + i - 32, tdata[i]);
+
+        usbhid_submit_report(data->hdev, report1, USB_DIR_OUT);
+        usbhid_submit_report(data->hdev, report2, USB_DIR_OUT);
+        spin_unlock_irqrestore(&data->lock, flags);
+        return 0;
+}
+
+/* Translate a single tile*/
+static int picolcd_fb_update_tile(u8 *vbitmap, const u8 *bitmap, int bpp,
+                int chip, int tile)
+{
+        int i, b, changed = 0;
+        u8 tdata[64];
+        u8 *vdata = vbitmap + (tile * 4 + chip) * 64;
+
+        if (bpp == 1) {
+                for (b = 7; b >= 0; b--) {
+                        const u8 *bdata = bitmap + tile * 256 + chip * 8 + b * 32;
+                        for (i = 0; i < 64; i++) {
+                                tdata[i] <<= 1;
+                                tdata[i] |= (bdata[i/8] >> (7 - i % 8)) & 0x01;
+                        }
+                }
+        } else if (bpp == 8) {
+                for (b = 7; b >= 0; b--) {
+                        const u8 *bdata = bitmap + (tile * 256 + chip * 8 + b * 32) * 8;
+                        for (i = 0; i < 64; i++) {
+                                tdata[i] <<= 1;
+                                tdata[i] |= (bdata[i] & 0x80) ? 0x01 : 0x00;
+                        }
+                }
+        } else {
+                /* Oops, we should never get here! */
+                WARN_ON(1);
+                return 0;
+        }
+
+        for (i = 0; i < 64; i++)
+                if (tdata[i] != vdata[i]) {
+                        changed = 1;
+                        vdata[i] = tdata[i];
+                }
+        return changed;
+}
+
+/* Reconfigure LCD display */
+static int picolcd_fb_reset(struct picolcd_data *data, int clear)
+{
+        struct hid_report *report = picolcd_out_report(REPORT_LCD_CMD, data->hdev);
+        int i, j;
+        unsigned long flags;
+        static const u8 mapcmd[8] = { 0x00, 0x02, 0x00, 0x64, 0x3f, 0x00, 0x64, 0xc0 };
+
+        if (!report || report->maxfield != 1)
+                return -ENODEV;
+
+        spin_lock_irqsave(&data->lock, flags);
+        for (i = 0; i < 4; i++) {
+                for (j = 0; j < report->field[0]->maxusage; j++)
+                        if (j == 0)
+                                hid_set_field(report->field[0], j, i << 2);
+                        else if (j < sizeof(mapcmd))
+                                hid_set_field(report->field[0], j, mapcmd[j]);
+                        else
+                                hid_set_field(report->field[0], j, 0);
+                usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+        }
+
+        data->status |= PICOLCD_READY_FB;
+        spin_unlock_irqrestore(&data->lock, flags);
+
+        if (data->fb_bitmap) {
+                if (clear) {
+                        memset(data->fb_vbitmap, 0xff, PICOLCDFB_SIZE);
+                        memset(data->fb_bitmap, 0, PICOLCDFB_SIZE*data->fb_bpp);
+                } else {
+                        /* invert 1 byte in each tile to force resend */
+                        for (i = 0; i < PICOLCDFB_SIZE; i += 64)
+                                data->fb_vbitmap[i] = ~data->fb_vbitmap[i];
+                }
+        }
+
+        /* schedule first output of framebuffer */
+        if (data->fb_info)
+                schedule_delayed_work(&data->fb_info->deferred_work, 0);
+
+        return 0;
+}
+
+/* Update fb_vbitmap from the screen_base and send changed tiles to device */
+static void picolcd_fb_update(struct picolcd_data *data)
+{
+        int chip, tile, n;
+        unsigned long flags;
+
+        spin_lock_irqsave(&data->lock, flags);
+        if (!(data->status & PICOLCD_READY_FB)) {
+                spin_unlock_irqrestore(&data->lock, flags);
+                picolcd_fb_reset(data, 0);
+        } else {
+                spin_unlock_irqrestore(&data->lock, flags);
+        }
+
+        /*
+         * Translate the framebuffer into the format needed by the PicoLCD.
+         * See display layout above.
+         * Do this one tile after the other and push those tiles that changed.
+         *
+         * Wait for our IO to complete as otherwise we might flood the queue!
+         */
+        n = 0;
+        for (chip = 0; chip < 4; chip++)
+                for (tile = 0; tile < 8; tile++)
+                        if (picolcd_fb_update_tile(data->fb_vbitmap,
+                                        data->fb_bitmap, data->fb_bpp, chip, tile)) {
+                                n += 2;
+                                if (n >= HID_OUTPUT_FIFO_SIZE / 2) {
+                                        usbhid_wait_io(data->hdev);
+                                        n = 0;
+                                }
+                                picolcd_fb_send_tile(data->hdev, chip, tile);
+                        }
+        if (n)
+                usbhid_wait_io(data->hdev);
+}
+
+/* Stub to call the system default and update the image on the picoLCD */
+static void picolcd_fb_fillrect(struct fb_info *info,
+                const struct fb_fillrect *rect)
+{
+        if (!info->par)
+                return;
+        sys_fillrect(info, rect);
+
+        schedule_delayed_work(&info->deferred_work, 0);
+}
+
+/* Stub to call the system default and update the image on the picoLCD */
+static void picolcd_fb_copyarea(struct fb_info *info,
+                const struct fb_copyarea *area)
+{
+        if (!info->par)
+                return;
+        sys_copyarea(info, area);
+
+        schedule_delayed_work(&info->deferred_work, 0);
+}
+
+/* Stub to call the system default and update the image on the picoLCD */
+static void picolcd_fb_imageblit(struct fb_info *info, const struct fb_image *image)
+{
+        if (!info->par)
+                return;
+        sys_imageblit(info, image);
+
+        schedule_delayed_work(&info->deferred_work, 0);
+}
+
+/*
+ * this is the slow path from userspace. they can seek and write to
+ * the fb. it's inefficient to do anything less than a full screen draw
+ */
+static ssize_t picolcd_fb_write(struct fb_info *info, const char __user *buf,
+                size_t count, loff_t *ppos)
+{
+        ssize_t ret;
+        if (!info->par)
+                return -ENODEV;
+        ret = fb_sys_write(info, buf, count, ppos);
+        if (ret >= 0)
+                schedule_delayed_work(&info->deferred_work, 0);
+        return ret;
+}
+
+static int picolcd_fb_blank(int blank, struct fb_info *info)
+{
+        if (!info->par)
+                return -ENODEV;
+        /* We let fb notification do this for us via lcd/backlight device */
+        return 0;
+}
+
+static void picolcd_fb_destroy(struct fb_info *info)
+{
+        struct picolcd_data *data = info->par;
+        info->par = NULL;
+        if (data)
+                data->fb_info = NULL;
+        fb_deferred_io_cleanup(info);
+        framebuffer_release(info);
+}
+
+static int picolcd_fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+        __u32 bpp      = var->bits_per_pixel;
+        __u32 activate = var->activate;
+
+        /* only allow 1/8 bit depth (8-bit is grayscale) */
+        *var = picolcdfb_var;
+        var->activate = activate;
+        if (bpp >= 8)
+                var->bits_per_pixel = 8;
+        else
+                var->bits_per_pixel = 1;
+        return 0;
+}
+
+static int picolcd_set_par(struct fb_info *info)
+{
+        struct picolcd_data *data = info->par;
+        u8 *o_fb, *n_fb;
+        if (info->var.bits_per_pixel == data->fb_bpp)
+                return 0;
+        /* switch between 1/8 bit depths */
+        if (info->var.bits_per_pixel != 1 && info->var.bits_per_pixel != 8)
+                return -EINVAL;
+
+        o_fb = data->fb_bitmap;
+        n_fb = vmalloc(PICOLCDFB_SIZE*info->var.bits_per_pixel);
+        if (!n_fb)
+                return -ENOMEM;
+
+        fb_deferred_io_cleanup(info);
+        /* translate FB content to new bits-per-pixel */
+        if (info->var.bits_per_pixel == 1) {
+                int i, b;
+                for (i = 0; i < PICOLCDFB_SIZE; i++) {
+                        u8 p = 0;
+                        for (b = 0; b < 8; b++) {
+                                p <<= 1;
+                                p |= o_fb[i*8+b] ? 0x01 : 0x00;
+                        }
+                }
+                info->fix.visual = FB_VISUAL_MONO01;
+                info->fix.line_length = PICOLCDFB_WIDTH / 8;
+        } else {
+                int i;
+                for (i = 0; i < PICOLCDFB_SIZE * 8; i++)
+                        n_fb[i] = o_fb[i/8] & (0x01 << (7 - i % 8)) ? 0xff : 0x00;
+                info->fix.visual = FB_VISUAL_TRUECOLOR;
+                info->fix.line_length = PICOLCDFB_WIDTH;
+        }
+
+        data->fb_bitmap   = n_fb;
+        data->fb_bpp      = info->var.bits_per_pixel;
+        info->screen_base = (char __force __iomem *)n_fb;
+        info->fix.smem_start = (unsigned long)n_fb;
+        info->fix.smem_len   = PICOLCDFB_SIZE*data->fb_bpp;
+        fb_deferred_io_init(info);
+        vfree(o_fb);
+        return 0;
+}
+
+/* Note this can't be const because of struct fb_info definition */
+static struct fb_ops picolcdfb_ops = {
+        .owner        = THIS_MODULE,
+        .fb_destroy   = picolcd_fb_destroy,
+        .fb_read      = fb_sys_read,
+        .fb_write     = picolcd_fb_write,
+        .fb_blank     = picolcd_fb_blank,
+        .fb_fillrect  = picolcd_fb_fillrect,
+        .fb_copyarea  = picolcd_fb_copyarea,
+        .fb_imageblit = picolcd_fb_imageblit,
+        .fb_check_var = picolcd_fb_check_var,
+        .fb_set_par   = picolcd_set_par,
+};
+
+
+/* Callback from deferred IO workqueue */
+static void picolcd_fb_deferred_io(struct fb_info *info, struct list_head *pagelist)
+{
+        picolcd_fb_update(info->par);
+}
+
+static const struct fb_deferred_io picolcd_fb_defio = {
+        .delay = HZ / PICOLCDFB_UPDATE_RATE_DEFAULT,
+        .deferred_io = picolcd_fb_deferred_io,
+};
+
+
+/*
+ * The "fb_update_rate" sysfs attribute
+ */
+static ssize_t picolcd_fb_update_rate_show(struct device *dev,
+                struct device_attribute *attr, char *buf)
+{
+        struct picolcd_data *data = dev_get_drvdata(dev);
+        unsigned i, fb_update_rate = data->fb_update_rate;
+        size_t ret = 0;
+
+        for (i = 1; i <= PICOLCDFB_UPDATE_RATE_LIMIT; i++)
+                if (ret >= PAGE_SIZE)
+                        break;
+                else if (i == fb_update_rate)
+                        ret += snprintf(buf+ret, PAGE_SIZE-ret, "[%u] ", i);
+                else
+                        ret += snprintf(buf+ret, PAGE_SIZE-ret, "%u ", i);
+        if (ret > 0)
+                buf[min(ret, (size_t)PAGE_SIZE)-1] = '\n';
+        return ret;
+}
+
+static ssize_t picolcd_fb_update_rate_store(struct device *dev,
+                struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct picolcd_data *data = dev_get_drvdata(dev);
+        int i;
+        unsigned u;
+
+        if (count < 1 || count > 10)
+                return -EINVAL;
+
+        i = sscanf(buf, "%u", &u);
+        if (i != 1)
+                return -EINVAL;
+
+        if (u > PICOLCDFB_UPDATE_RATE_LIMIT)
+                return -ERANGE;
+        else if (u == 0)
+                u = PICOLCDFB_UPDATE_RATE_DEFAULT;
+
+        data->fb_update_rate = u;
+        data->fb_defio.delay = HZ / data->fb_update_rate;
+        return count;
+}
+
+static DEVICE_ATTR(fb_update_rate, 0666, picolcd_fb_update_rate_show,
+                picolcd_fb_update_rate_store);
+
+/* initialize Framebuffer device */
+static int picolcd_init_framebuffer(struct picolcd_data *data)
+{
+        struct device *dev = &data->hdev->dev;
+        struct fb_info *info = NULL;
+        int error = -ENOMEM;
+        u8 *fb_vbitmap = NULL;
+        u8 *fb_bitmap  = NULL;
+
+        fb_bitmap = vmalloc(PICOLCDFB_SIZE*picolcdfb_var.bits_per_pixel);
+        if (fb_bitmap == NULL) {
+                dev_err(dev, "can't get a free page for framebuffer\n");
+                goto err_nomem;
+        }
+
+        fb_vbitmap = kmalloc(PICOLCDFB_SIZE, GFP_KERNEL);
+        if (fb_vbitmap == NULL) {
+                dev_err(dev, "can't alloc vbitmap image buffer\n");
+                goto err_nomem;
+        }
+
+        data->fb_update_rate = PICOLCDFB_UPDATE_RATE_DEFAULT;
+        data->fb_defio = picolcd_fb_defio;
+        info = framebuffer_alloc(0, dev);
+        if (info == NULL) {
+                dev_err(dev, "failed to allocate a framebuffer\n");
+                goto err_nomem;
+        }
+
+        info->fbdefio = &data->fb_defio;
+        info->screen_base = (char __force __iomem *)fb_bitmap;
+        info->fbops = &picolcdfb_ops;
+        info->var = picolcdfb_var;
+        info->fix = picolcdfb_fix;
+        info->fix.smem_len   = PICOLCDFB_SIZE;
+        info->fix.smem_start = (unsigned long)fb_bitmap;
+        info->par = data;
+        info->flags = FBINFO_FLAG_DEFAULT;
+
+        data->fb_vbitmap = fb_vbitmap;
+        data->fb_bitmap  = fb_bitmap;
+        data->fb_bpp     = picolcdfb_var.bits_per_pixel;
+        error = picolcd_fb_reset(data, 1);
+        if (error) {
+                dev_err(dev, "failed to configure display\n");
+                goto err_cleanup;
+        }
+        error = device_create_file(dev, &dev_attr_fb_update_rate);
+        if (error) {
+                dev_err(dev, "failed to create sysfs attributes\n");
+                goto err_cleanup;
+        }
+        data->fb_info    = info;
+        error = register_framebuffer(info);
+        if (error) {
+                dev_err(dev, "failed to register framebuffer\n");
+                goto err_sysfs;
+        }
+        fb_deferred_io_init(info);
+        /* schedule first output of framebuffer */
+        schedule_delayed_work(&info->deferred_work, 0);
+        return 0;
+
+err_sysfs:
+        device_remove_file(dev, &dev_attr_fb_update_rate);
+err_cleanup:
+        data->fb_vbitmap = NULL;
+        data->fb_bitmap  = NULL;
+        data->fb_bpp     = 0;
+        data->fb_info    = NULL;
+
+err_nomem:
+        framebuffer_release(info);
+        vfree(fb_bitmap);
+        kfree(fb_vbitmap);
+        return error;
+}
+
+static void picolcd_exit_framebuffer(struct picolcd_data *data)
+{
+        struct fb_info *info = data->fb_info;
+        u8 *fb_vbitmap = data->fb_vbitmap;
+        u8 *fb_bitmap  = data->fb_bitmap;
+
+        if (!info)
+                return;
+
+        data->fb_vbitmap = NULL;
+        data->fb_bitmap  = NULL;
+        data->fb_bpp     = 0;
+        data->fb_info    = NULL;
+        device_remove_file(&data->hdev->dev, &dev_attr_fb_update_rate);
+        fb_deferred_io_cleanup(info);
+        unregister_framebuffer(info);
+        vfree(fb_bitmap);
+        kfree(fb_vbitmap);
+}
+
+
+#else
+static inline int picolcd_fb_reset(struct picolcd_data *data, int clear)
+{
+        return 0;
+}
+static inline int picolcd_init_framebuffer(struct picolcd_data *data)
+{
+        return 0;
+}
+static void picolcd_exit_framebuffer(struct picolcd_data *data)
+{
+}
+#endif /* CONFIG_FB */
+
 /*
  * input class device
  */
@@ -314,6 +861,7 @@ static int picolcd_reset(struct hid_device *hdev)
         struct picolcd_data *data = hid_get_drvdata(hdev);
         struct hid_report *report = picolcd_out_report(REPORT_RESET, hdev);
         unsigned long flags;
+        int error;
 
         if (!data || !report || report->maxfield != 1)
                 return -ENODEV;
@@ -327,7 +875,16 @@ static int picolcd_reset(struct hid_device *hdev)
         usbhid_submit_report(hdev, report, USB_DIR_OUT);
         spin_unlock_irqrestore(&data->lock, flags);
 
-        return picolcd_check_version(hdev);
+        error = picolcd_check_version(hdev);
+        if (error)
+                return error;
+
+#if defined(CONFIG_FB) || defined(CONFIG_FB_MODULE)
+        if (data->fb_info)
+                schedule_delayed_work(&data->fb_info->deferred_work, 0);
+#endif /* CONFIG_FB */
+
+        return 0;
 }
 
 /*
@@ -1005,6 +1562,11 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
         if (error)
                 goto err;
 
+        /* Set up the framebuffer device */
+        error = picolcd_init_framebuffer(data);
+        if (error)
+                goto err;
+
 #ifdef CONFIG_DEBUG_FS
         report = picolcd_out_report(REPORT_READ_MEMORY, hdev);
         if (report && report->maxfield == 1 && report->field[0]->report_size == 8)
@@ -1014,6 +1576,7 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
 #endif
         return 0;
 err:
+        picolcd_exit_framebuffer(data);
         picolcd_exit_cir(data);
         picolcd_exit_keys(data);
         return error;
@@ -1143,6 +1706,8 @@ static void picolcd_remove(struct hid_device *hdev)
                 complete(&data->pending->ready);
         spin_unlock_irqrestore(&data->lock, flags);
 
+        /* Clean up the framebuffer */
+        picolcd_exit_framebuffer(data);
         /* Cleanup input */
         picolcd_exit_cir(data);
         picolcd_exit_keys(data);
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index 56d06cd8075b..3e7909b0f129 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -623,6 +623,7 @@ int usbhid_wait_io(struct hid_device *hid)
 
         return 0;
 }
+EXPORT_SYMBOL_GPL(usbhid_wait_io);
 
 static int hid_set_idle(struct usb_device *dev, int ifnum, int report, int idle)
 {