[PATCH 1/3] picolcd: driver for PicoLCD HID device

[PATCH 1/3] picolcd: driver for PicoLCD HID device

[Bruno Prémont]

Driver for graphic PicoLCD device ( http://www.picolcd.com ) with
framebuffer support (using deferredio), backlight control via backlight
class, contrast control via lcd class and input for keypad.

More features of the device include CIR and GPIO, support for them will
be added at a later time.

Signed-off-by: Bruno Prémont <bonbons-ud5FBsm0p/xEiooADzr8i9i2O/JbrIOy@public.gmane.org>
Cc: Nicu Pavel <npavel-VxACSXvuqMTQT0dZR+AlfA@public.gmane.org>
---
Note, this patch requires
  "backlight: Add backlight_device parameter to check_fb"

Some lines are longer than suggested 80 columns, especially those for
the declaration of initial framebuffer content that I did format one
framebuffer line (256 pixel) per source line.

 drivers/hid/Kconfig                 |   18 ++
 drivers/hid/Makefile                |    1 +
 drivers/hid/hid-core.c              |    1 +
 drivers/hid/hid-ids.h               |    1 +
 drivers/hid/hid-picolcd.c           | 1075 +++++++++++++++++++++++++
 5 files changed, 1096 insertions(+), 0 deletions(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 24d90ea..55915c8 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -183,6 +183,24 @@ config LOGIRUMBLEPAD2_FF
 	  Say Y here if you want to enable force feedback support for Logitech
 	  Rumblepad 2 devices.
 
+config HID_PICOLCD
+	tristate "Minibox PicoLCD (graphic version)"
+	depends on FB
+	select FB_DEFERRED_IO
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select BACKLIGHT_LCD_SUPPORT
+	select BACKLIGHT_CLASS_DEVICE
+	select LCD_CLASS_DEVICE
+	help
+	  This provides support for Minibox PicoLCD devices, currently
+	  only the graphical ones are supported. This includes support
+	  for the device as a keypad input with mappable keys as well as
+	  a framebuffer for the LCD display.
+	  Support for the GPIOs and IR is not yet implemented
+
 config HID_MICROSOFT
 	tristate "Microsoft" if EMBEDDED
 	depends on USB_HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 0de2dff..450f09f 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_HID_GYRATION)	+= hid-gyration.o
 obj-$(CONFIG_HID_KENSINGTON)	+= hid-kensington.o
 obj-$(CONFIG_HID_KYE)		+= hid-kye.o
 obj-$(CONFIG_HID_LOGITECH)	+= hid-logitech.o
+obj-$(CONFIG_HID_PICOLCD)	+= hid-picolcd.o
 obj-$(CONFIG_HID_MICROSOFT)	+= hid-microsoft.o
 obj-$(CONFIG_HID_MONTEREY)	+= hid-monterey.o
 obj-$(CONFIG_HID_NTRIG)		+= hid-ntrig.o
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index eabe5f8..1db0b3a 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1330,6 +1330,7 @@ static const struct hid_device_id hid_blacklist[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_LOGITECH_RUMBLEPAD2) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_SPACETRAVELLER) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_SPACENAVIGATOR) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_PICOLCD) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROSOFT, USB_DEVICE_ID_SIDEWINDER_GV) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROSOFT, USB_DEVICE_ID_MS_NE4K) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROSOFT, USB_DEVICE_ID_MS_LK6K) },
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 010368e..fc66622 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -330,6 +330,7 @@
 #define USB_VENDOR_ID_MICROCHIP		0x04d8
 #define USB_DEVICE_ID_PICKIT1		0x0032
 #define USB_DEVICE_ID_PICKIT2		0x0033
+#define USB_DEVICE_ID_PICOLCD		0xc002
 
 #define USB_VENDOR_ID_MICROSOFT		0x045e
 #define USB_DEVICE_ID_SIDEWINDER_GV	0x003b
diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index e69de29..90f6be5 100644
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -0,0 +1,1075 @@
+/***************************************************************************
+ *   Copyright (C) 2010 by Bruno Prémont <bonbons@linux-vserver.org>       *
+ *                                                                         *
+ *   Based on Logitech G13 driver (v0.4)                                   *
+ *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard-qcTL/1vZYtjHfRtnQztjLA@public.gmane.orgu>   *
+ *                                                                         *
+ *   This program is free software: you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation, either version 2 of the License.        *
+ *                                                                         *
+ *   This driver is distributed in the hope that it will be useful, but    *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
+ *   General Public License for more details.                              *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this software. If not see <http://www.gnu.org/licenses/>.  *
+ ***************************************************************************/
+
+#include <linux/hid.h>
+#include <linux/input.h>
+#include "hid-ids.h"
+#include "usbhid/usbhid.h"
+#include <linux/usb.h>
+
+#include <linux/fb.h>
+#include <linux/backlight.h>
+#include <linux/lcd.h>
+#include <linux/vmalloc.h>
+
+#include <linux/completion.h>
+
+#define PICOLCD_NAME "PicoLCD (graphic)"
+
+/* Report numbers */
+#define REPORT_BRIGHTNESS   0x91
+#define REPORT_CONTRAST     0x92
+#define REPORT_RESET        0x93
+#define REPORT_LCD_CMD      0x94
+#define REPORT_LCD_DATA     0x95
+#define REPORT_LCD_CMD_DATA 0x96
+#define REPORT_VERSION      0xf1
+#define REPORT_SPLASH_SIZE  0xf6
+#define REPORT_KEYPAD       0x11
+/* Additional features of picoLCD that are not supported yet:
+ *  - CIR
+ *  - GPIO
+ *  - Programming / flashing (full firmware or just splash?)
+ *  - interface to ICSP header?
+ */
+
+/* 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_LINE_LENGTH (256/8)
+#define PICOLCDFB_HEIGHT (64)
+#define PICOLCDFB_SIZE (PICOLCDFB_LINE_LENGTH*PICOLCDFB_HEIGHT)
+
+#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_LINE_LENGTH,
+	.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,
+};
+
+#ifdef CONFIG_LOGO
+/*
+ * This is a default logo to be loaded upon driver initialization
+ * replacing the default PicoLCD image loaded on device
+ * initialization. This is to provide the user a cue that the
+ * Linux driver is loaded and ready.
+ *
+ * This logo contains the text PicoLCD in the center with one penguin
+ * on each side of the text. The penguins are a 64x64 rendition of
+ * the default framebuffer 80x80 monochrome image scaled down and
+ * cleaned up to retain something that looks a little better than
+ * a simple scaling.
+ *
+ * This logo is a simple xbm image created in GIMP and exported.
+ * To view the image copy the following two #defines plus the
+ * picolcd_bits to an ASCII text file and save with extension
+ * .xbm, then open with GIMP or any other graphical editor
+ * such as eog that recognizes the .xbm format.
+ */
+#define picolcd_width 256
+#define picolcd_height 64
+static const u8 picolcd_bits[PICOLCDFB_SIZE] = {
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xf8, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf8, 0x1f, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xe7, 0xe7, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe7, 0xe7, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xdf, 0xf9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xdf, 0xf9, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xbf, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xbf, 0xfe, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0x7f, 0xff, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f, 0xff, 0x7f, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0x7f, 0xcf, 0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f, 0xcf, 0xbf, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0x7f, 0xdf, 0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f, 0xdf, 0xbf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xff, 0xff, 0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xff, 0xff, 0xbf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xff, 0xff, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xff, 0xff, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xff, 0xff, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xff, 0xff, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xcf, 0x8f, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xcf, 0x8f, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xc7, 0x07, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xc7, 0x07, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xd3, 0x67, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xd3, 0x67, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xfb, 0x73, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xfb, 0x73, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xff, 0xf3, 0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xff, 0xf3, 0xbf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xf0, 0x37, 0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xf0, 0x37, 0xbf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xc5, 0x0f, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xc5, 0x0f, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xc0, 0x1b, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xc0, 0x1b, 0xdf, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xc0, 0x27, 0xef, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xc0, 0x27, 0xef, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xe0, 0xc7, 0xef, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe3, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xfe, 0x00, 0x78, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xe0, 0xc7, 0xef, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xff, 0x1b, 0x67, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe3, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xfc, 0x00, 0x38, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xff, 0x1b, 0x67, 0xff, 0xff,
+	0xff, 0xff, 0xfe, 0xd0, 0xc3, 0xb7, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe3, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xfc, 0x00, 0x38, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xfe, 0xd0, 0xc3, 0xb7, 0xff, 0xff,
+	0xff, 0xff, 0xfd, 0xcf, 0x03, 0xfb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xfc, 0x7e, 0x38, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xcf, 0x03, 0xfb, 0xff, 0xff,
+	0xff, 0xff, 0xfd, 0xc0, 0x01, 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xc0, 0x01, 0xfd, 0xff, 0xff,
+	0xff, 0xff, 0xfb, 0x80, 0x01, 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xfb, 0x80, 0x01, 0xfd, 0xff, 0xff,
+	0xff, 0xff, 0xf7, 0x00, 0x00, 0xfe, 0xff, 0xff, 0xff, 0xf1, 0x01, 0xe3, 0xc0, 0x0f, 0x80, 0x1e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xf7, 0x00, 0x00, 0xfe, 0xff, 0xff,
+	0xff, 0xff, 0xef, 0x00, 0x00, 0xff, 0x7f, 0xff, 0xff, 0xf0, 0x00, 0xe3, 0x80, 0x07, 0x00, 0x0e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xef, 0x00, 0x00, 0xff, 0x7f, 0xff,
+	0xff, 0xff, 0xef, 0x00, 0x00, 0x7f, 0x7f, 0xff, 0xff, 0xf0, 0x00, 0xe3, 0x80, 0x07, 0x00, 0x0e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xef, 0x00, 0x00, 0x7f, 0x7f, 0xff,
+	0xff, 0xff, 0xdf, 0x8c, 0x0f, 0x7f, 0xbf, 0xff, 0xff, 0xf1, 0xf8, 0xe3, 0x8f, 0xc7, 0x1f, 0x8e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xdf, 0x8c, 0x0f, 0x7f, 0xbf, 0xff,
+	0xff, 0xff, 0xde, 0x08, 0x07, 0xbf, 0xdf, 0xff, 0xff, 0xf1, 0xf8, 0xe3, 0x8f, 0xff, 0x1f, 0x8e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xde, 0x08, 0x07, 0xbf, 0xdf, 0xff,
+	0xff, 0xff, 0xbc, 0x00, 0x01, 0xff, 0xdf, 0xff, 0xff, 0xf1, 0xf8, 0xe3, 0x8f, 0xff, 0x1f, 0x8e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xbc, 0x00, 0x01, 0xff, 0xdf, 0xff,
+	0xff, 0xff, 0xbc, 0x00, 0x00, 0x7f, 0xdf, 0xff, 0xff, 0xf1, 0xf8, 0xe3, 0x8f, 0xff, 0x1f, 0x8e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xbc, 0x00, 0x00, 0x7f, 0xdf, 0xff,
+	0xff, 0xff, 0x78, 0x00, 0x00, 0x1f, 0xef, 0xff, 0xff, 0xf1, 0xf8, 0xe3, 0x8f, 0xff, 0x1f, 0x8e, 0x3f, 0xfc, 0x7f, 0xf8, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xff, 0x78, 0x00, 0x00, 0x1f, 0xef, 0xff,
+	0xff, 0xfe, 0xf8, 0x00, 0x00, 0x1d, 0xe7, 0xff, 0xff, 0xf1, 0xf8, 0xe3, 0x8f, 0xc7, 0x1f, 0x8e, 0x3f, 0x1c, 0x7e, 0x38, 0xfc, 0x7f, 0xff, 0xff, 0xff, 0xfe, 0xf8, 0x00, 0x00, 0x1d, 0xe7, 0xff,
+	0xff, 0xfe, 0xf0, 0x00, 0x00, 0x1d, 0xf7, 0xff, 0xff, 0xf0, 0x00, 0xe3, 0x80, 0x07, 0x00, 0x0e, 0x00, 0x1c, 0x00, 0x38, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xfe, 0xf0, 0x00, 0x00, 0x1d, 0xf7, 0xff,
+	0xff, 0xfd, 0xf0, 0x00, 0x00, 0x1d, 0xf7, 0xff, 0xff, 0xf0, 0x00, 0xe3, 0x80, 0x07, 0x00, 0x0e, 0x00, 0x1c, 0x00, 0x38, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xfd, 0xf0, 0x00, 0x00, 0x1d, 0xf7, 0xff,
+	0xff, 0xfd, 0xf0, 0x00, 0x00, 0x0e, 0xfb, 0xff, 0xff, 0xf1, 0x01, 0xe3, 0xc0, 0x0f, 0x80, 0x1e, 0x00, 0x1e, 0x00, 0x78, 0x00, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xf0, 0x00, 0x00, 0x0e, 0xfb, 0xff,
+	0xff, 0xfd, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff, 0xff, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff,
+	0xff, 0xfb, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff, 0xff, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf9, 0x86, 0x7f, 0x3b, 0xff, 0xff, 0xff, 0xff, 0xfb, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff,
+	0xff, 0xfb, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff, 0xff, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf6, 0xbd, 0xfe, 0xfb, 0xff, 0xff, 0xff, 0xff, 0xfb, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff,
+	0xff, 0xfb, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff, 0xff, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x8c, 0x6a, 0x36, 0xff, 0xff, 0xff, 0xff, 0xfb, 0xe0, 0x10, 0x00, 0x0e, 0xfb, 0xff,
+	0xff, 0xfb, 0xe0, 0x10, 0x00, 0x10, 0x3b, 0xff, 0xff, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0xf5, 0xb6, 0xd0, 0xff, 0xff, 0xff, 0xff, 0xfb, 0xe0, 0x10, 0x00, 0x10, 0x3b, 0xff,
+	0xff, 0xfa, 0x30, 0x00, 0x00, 0x7f, 0xdb, 0xff, 0xff, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfb, 0xf5, 0xaa, 0xde, 0xff, 0xff, 0xff, 0xff, 0xfa, 0x30, 0x00, 0x00, 0x7f, 0xdb, 0xff,
+	0xff, 0xfc, 0x38, 0x00, 0x00, 0x4f, 0xe7, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x8e, 0x7f, 0x3e, 0xff, 0xff, 0xff, 0xff, 0xfc, 0x38, 0x00, 0x00, 0x4f, 0xe7, 0xff,
+	0xff, 0xf8, 0x1c, 0x00, 0x00, 0x8f, 0xc7, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf8, 0x1c, 0x00, 0x00, 0x8f, 0xc7, 0xff,
+	0xff, 0xf0, 0x07, 0x00, 0x00, 0x87, 0x87, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x07, 0x00, 0x00, 0x87, 0x87, 0xff,
+	0xff, 0xc0, 0x07, 0x80, 0x00, 0x80, 0x07, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 0x07, 0x80, 0x00, 0x80, 0x07, 0xff,
+	0xff, 0x00, 0x03, 0xc0, 0x00, 0x80, 0x07, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x03, 0xc0, 0x00, 0x80, 0x07, 0xff,
+	0xff, 0x00, 0x03, 0xc0, 0x00, 0x80, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x03, 0xc0, 0x00, 0x80, 0x03, 0xff,
+	0xff, 0x00, 0x01, 0xc0, 0x00, 0x80, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01, 0xc0, 0x00, 0x80, 0x00, 0xff,
+	0xff, 0x00, 0x01, 0xc0, 0x01, 0x80, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01, 0xc0, 0x01, 0x80, 0x00, 0x7f,
+	0xff, 0x00, 0x00, 0x80, 0x03, 0x80, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x80, 0x03, 0x80, 0x00, 0x7f,
+	0xff, 0x00, 0x00, 0x40, 0x07, 0x80, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x40, 0x07, 0x80, 0x00, 0x7f,
+	0xff, 0x00, 0x00, 0x00, 0x3f, 0x80, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x3f, 0x80, 0x01, 0xff,
+	0xff, 0x00, 0x00, 0x3f, 0xff, 0x00, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x3f, 0xff, 0x00, 0x03, 0xff,
+	0xff, 0x00, 0x00, 0x3f, 0xff, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x3f, 0xff, 0x00, 0x0f, 0xff,
+	0xff, 0x80, 0x00, 0x3f, 0xff, 0x00, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x80, 0x00, 0x3f, 0xff, 0x00, 0x1f, 0xff,
+	0xff, 0xfc, 0x00, 0x38, 0x03, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfc, 0x00, 0x38, 0x03, 0x00, 0x7f, 0xff,
+	0xff, 0xff, 0xc0, 0x07, 0xfc, 0x80, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 0x07, 0xfc, 0x80, 0xff, 0xff,
+	0xff, 0xff, 0xe0, 0x7f, 0xff, 0x81, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x7f, 0xff, 0x81, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
+};
+#endif
+
+
+/* Input device
+ *
+ * The PicoLCD has an IR receiver header, a built-in keypad with 5 keys
+ * and header for 4x4 key matrix. The built-in keys are part of the matrix.
+ */
+#define PICOLCD_KEYS 33
+
+static const int def_keymap[PICOLCD_KEYS] = {
+	KEY_RESERVED, KEY_BACK, KEY_HOMEPAGE, KEY_RESERVED, KEY_RESERVED, KEY_SCROLLUP, KEY_OK, KEY_SCROLLDOWN,
+	KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
+	KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
+	KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
+	KEY_RESERVED
+};
+
+
+
+/* Per device data structure */
+struct picolcd_data {
+	struct hid_device *hdev;
+
+	/* input stuff */
+	struct input_dev *input_keys;
+	struct input_dev *input_cir;
+	int keycode[PICOLCD_KEYS];
+	u8 pressed_keys[2];
+
+	/* Framebuffer stuff */
+	u8 fb_update_rate;
+	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;
+	struct lcd_device *lcd;
+	struct backlight_device *backlight;
+	int lcd_contrast;
+	int lcd_power;
+	int lcd_brightness;
+
+	/* GPIO stuff */
+
+	/* Housekeeping stuff */
+	spinlock_t lock;
+	struct completion ready;
+	int status;
+#define PICOLCD_READY_ALIVE 1
+#define PICOLCD_READY_FB 2
+#define PICOLCD_READY_ALL (PICOLCD_READY_ALIVE | PICOLCD_READY_FB)
+};
+
+
+
+/* Find a given output report */
+static struct hid_report *picolcd_out_report(int id, struct hid_device *hdev)
+{
+	struct list_head *feature_report_list = &hdev->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct hid_report *report = NULL;
+
+	list_for_each_entry(report, feature_report_list, list) {
+		if (report->id == id)
+			return report;
+	}
+	dev_err(&hdev->dev, "No report with id 0x%x found\n", id);
+	return NULL;
+}
+
+
+
+/* Send a given tile to PicoLCD */
+static inline 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);
+	u8 *tdata;
+	int i;
+
+	if (!report1 || report1->maxfield != 1 || !report2 || report2->maxfield != 1)
+		return -ENODEV;
+
+	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);
+	return 0;
+}
+
+/* Translate a single tile*/
+static inline int picolcd_fb_update_tile(u8 *vbitmap, const u8 *bitmap,
+		int chip, int tile)
+{
+	int i, b, changed = 0;
+	u8 tdata[64];
+	u8 *vdata = vbitmap + (tile * 4 + chip) * 64;
+
+	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;
+		}
+	}
+	for (i = 0; i < 64; i++)
+		if (tdata[i] != vdata[i]) {
+			changed = 1;
+			vdata[i] = tdata[i];
+		}
+	return changed;
+}
+
+/* Reconfigure LCD display
+ *   TODO: prevent concurrent runs */
+static int picolcd_fb_reset(struct hid_device *hdev, int clear)
+{
+	struct picolcd_data *data = hid_get_drvdata(hdev);
+	struct hid_report *report = picolcd_out_report(REPORT_LCD_CMD, hdev);
+	int chip, tile, i, j;
+	static const u8 mapcmd[8] = { 0x00, 0x02, 0x00, 0x64, 0x3f, 0x00, 0x64, 0xc0 };
+
+	if (!report || report->maxfield != 1)
+		return -ENODEV;
+
+	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);
+	}
+
+	if (!clear) {
+		spin_lock(&data->lock);
+		data->status |= PICOLCD_READY_FB;
+		spin_unlock(&data->lock);
+		for (chip = 0; chip < 4; chip++)
+			for (tile = 0; tile < 8; tile++) {
+				i = picolcd_fb_send_tile(data->hdev, chip, tile);
+				if (i != 0)
+					return i;
+			}
+		return 0;
+	}
+
+#ifdef CONFIG_LOGO
+	memcpy(data->fb_bitmap, picolcd_bits, PICOLCDFB_SIZE);
+#else
+	memset(data->fb_bitmap, 0, PICOLCDFB_SIZE);
+#endif
+	for (chip = 0; chip < 4; chip++)
+		for (tile = 0; tile < 8; tile++) {
+			picolcd_fb_update_tile(data->fb_vbitmap,
+					data->fb_bitmap, chip, tile);
+			i = picolcd_fb_send_tile(data->hdev, chip, tile);
+			if (i != 0)
+				return i;
+		}
+
+	spin_lock(&data->lock);
+	data->status |= PICOLCD_READY_FB;
+	spin_unlock(&data->lock);
+	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;
+
+	spin_lock(&data->lock);
+	if (!(data->status & PICOLCD_READY_FB)) {
+		spin_unlock(&data->lock);
+		picolcd_fb_reset(data->hdev, 0);
+	} else
+		spin_unlock(&data->lock);
+
+	/*
+	 * Translate the XBM format screen_base into the format needed by the
+	 * PicoLCD. See display layout above.
+	 * Do this one tile after the other and push those tiles that changed.
+	 */
+	for (chip = 0; chip < 4; chip++)
+		for (tile = 0; tile < 8; tile++)
+			if (picolcd_fb_update_tile(data->fb_vbitmap,
+					data->fb_bitmap, chip, tile))
+				picolcd_fb_send_tile(data->hdev, chip, tile);
+}
+
+/* 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);
+
+	picolcd_fb_update(info->par);
+}
+
+/* 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);
+
+	picolcd_fb_update(info->par);
+}
+
+/* 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);
+
+	picolcd_fb_update(info->par);
+}
+
+/*
+ * 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)
+		picolcd_fb_update(info->par);
+	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)
+{
+	fb_deferred_io_cleanup(info);
+	if (info->par)
+		((struct picolcd_data *)info->par)->fb_info = NULL;
+	framebuffer_release(info);
+}
+
+/* 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,
+};
+
+
+/* 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" 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 fb_update_rate = data->fb_update_rate;
+
+	return snprintf(buf, PAGE_SIZE, "%u (1..%u)\n", fb_update_rate,
+			PICOLCDFB_UPDATE_RATE_LIMIT);
+}
+
+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);
+
+
+/*
+ * backlight class device
+ */
+static int picolcd_get_brightness(struct backlight_device *bdev)
+{
+	struct picolcd_data *data = bl_get_data(bdev);
+	return data->lcd_brightness;
+}
+
+static int picolcd_set_brightness(struct backlight_device *bdev)
+{
+	struct picolcd_data *data = bl_get_data(bdev);
+	struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
+
+	if (!report || report->maxfield != 1 || report->field[0]->maxusage != 1)
+		return -ENODEV;
+
+	data->lcd_brightness = bdev->props.brightness & 0x0ff;
+	data->lcd_power      = bdev->props.power;
+	hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
+	usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+	return 0;
+}
+
+static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
+{
+	struct picolcd_data *data = bl_get_data(bdev);
+	return fb == data->fb_info;
+}
+
+static const struct backlight_ops picolcd_blops = {
+	.update_status  = picolcd_set_brightness,
+	.get_brightness = picolcd_get_brightness,
+	.check_fb       = picolcd_check_bl_fb,
+};
+
+/*
+ * lcd class device
+ */
+static int picolcd_get_power(struct lcd_device *ldev)
+{
+	struct picolcd_data *data = lcd_get_data(ldev);
+	return data->lcd_power;
+}
+
+static int picolcd_set_power(struct lcd_device *ldev, int power)
+{
+	struct picolcd_data *data = lcd_get_data(ldev);
+	data->backlight->props.power = power;
+	return picolcd_set_brightness(data->backlight);
+}
+
+static int picolcd_get_contrast(struct lcd_device *ldev)
+{
+	struct picolcd_data *data = lcd_get_data(ldev);
+	return data->lcd_contrast;
+}
+
+static int picolcd_set_contrast(struct lcd_device *ldev, int contrast)
+{
+	struct picolcd_data *data = lcd_get_data(ldev);
+	struct hid_report *report = picolcd_out_report(REPORT_CONTRAST, data->hdev);
+
+	if (!report || report->maxfield != 1 || report->field[0]->maxusage != 1)
+		return -ENODEV;
+
+	data->lcd_contrast = contrast & 0x0ff;
+	hid_set_field(report->field[0], 0, data->lcd_contrast);
+	usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+	return 0;
+}
+
+static int picolcd_check_lcd_fb(struct lcd_device *ldev, struct fb_info *fb)
+{
+	struct picolcd_data *data = lcd_get_data(ldev);
+	return fb == data->fb_info;
+}
+
+static struct lcd_ops picolcd_lcdops = {
+	.get_power      = picolcd_get_power,
+	.set_power      = picolcd_set_power,
+	.get_contrast   = picolcd_get_contrast,
+	.set_contrast   = picolcd_set_contrast,
+	.check_fb       = picolcd_check_lcd_fb,
+};
+
+
+/*
+ * input class device
+ */
+static int picolcd_raw_keypad(struct hid_device *hdev,
+		struct hid_report *report, u8 *raw_data, int size)
+{
+	/*
+	 * Keypad event
+	 * First and second data bytes list currently pressed keys,
+	 * 0x00 means no key and at most 2 keys may be pressed at same time
+	 */
+	struct picolcd_data *data = hid_get_drvdata(hdev);
+	int i, j;
+
+	/* determine newly pressed keys */
+	for (i = 0; i < size; i++) {
+		int key_code;
+		if (raw_data[i] == 0)
+			continue;
+		for (j = 0; j < sizeof(data->pressed_keys); j++)
+			if (data->pressed_keys[j] == raw_data[i])
+				goto key_already_down;
+		for (j = 0; j < sizeof(data->pressed_keys); j++)
+			if (data->pressed_keys[j] == 0) {
+				data->pressed_keys[j] = raw_data[i];
+				break;
+			}
+		input_event(data->input_keys, EV_MSC, MSC_SCAN, raw_data[i]);
+		if (input_get_keycode(data->input_keys, raw_data[i], &key_code))
+			key_code = KEY_UNKNOWN;
+		if (key_code != KEY_UNKNOWN) {
+			dbg_hid(PICOLCD_NAME " got key press for %u:%d", raw_data[i], key_code);
+			input_report_key(data->input_keys, key_code, 1);
+		}
+		input_sync(data->input_keys);
+key_already_down:
+		continue;
+	}
+
+	/* determine newly released keys */
+	for (j = 0; j < sizeof(data->pressed_keys); j++) {
+		int key_code;
+		if (data->pressed_keys[j] == 0)
+			continue;
+		for (i = 0; i < size; i++)
+			if (data->pressed_keys[j] == raw_data[i])
+				goto key_still_down;
+		input_event(data->input_keys, EV_MSC, MSC_SCAN, data->pressed_keys[j]);
+		if (input_get_keycode(data->input_keys, data->pressed_keys[j], &key_code))
+			key_code = KEY_UNKNOWN;
+		if (key_code != KEY_UNKNOWN) {
+			dbg_hid(PICOLCD_NAME " got key release for %u:%d", data->pressed_keys[j], key_code);
+			input_report_key(data->input_keys, key_code, 0);
+		}
+		input_sync(data->input_keys);
+		data->pressed_keys[j] = 0;
+key_still_down:
+		continue;
+	}
+	return 1;
+}
+
+
+
+
+
+/*
+ * Reset our device and wait for answer to VERSION request
+ */
+static int picolcd_reset(struct hid_device *hdev)
+{
+	struct picolcd_data *data = hid_get_drvdata(hdev);
+	struct hid_report *report1 = picolcd_out_report(REPORT_RESET, hdev);
+	struct hid_report *report2 = picolcd_out_report(REPORT_VERSION, hdev);
+	int ret;
+
+	if (!report1 || report1->maxfield != 1 || !report2)
+		return -ENODEV;
+
+	spin_lock(&data->lock);
+	data->status = 0;
+	spin_unlock(&data->lock);
+	INIT_COMPLETION(data->ready);
+
+	hid_set_field(report1->field[0], 0, 1);
+	usbhid_submit_report(hdev, report1, USB_DIR_OUT);
+
+	usbhid_submit_report(hdev, report2, USB_DIR_OUT);
+	wait_for_completion_interruptible_timeout(&data->ready, HZ*2);
+
+	spin_lock(&data->lock);
+	if (data->status == 0) {
+		spin_unlock(&data->lock);
+		return -EBUSY;
+	} else
+		spin_unlock(&data->lock);
+
+	ret = picolcd_set_contrast(data->lcd, data->lcd_contrast);
+	if (ret)
+		return ret;
+	ret = picolcd_set_brightness(data->backlight);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/*
+ * The "reset" attribute
+ */
+static ssize_t picolcd_reset_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "all fb");
+}
+
+static ssize_t picolcd_reset_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct picolcd_data *data = dev_get_drvdata(dev);
+	size_t cnt = count;
+	while (cnt > 0 && (buf[cnt-1] == ' ' || buf[cnt-1] == '\n'))
+		cnt--;
+	if (strncmp(buf, "all", cnt) == 0) {
+		picolcd_reset(data->hdev);
+		picolcd_fb_reset(data->hdev, 1);
+	} else if (strncmp(buf, "fb", cnt) == 0) {
+		picolcd_fb_reset(data->hdev, 1);
+	} else
+		return -EINVAL;
+	return count;
+}
+
+static DEVICE_ATTR(reset, 0600, picolcd_reset_show,
+		picolcd_reset_store);
+
+
+
+/*
+ * Handle raw report as sent by device
+ */
+static int picolcd_raw_event(struct hid_device *hdev,
+		struct hid_report *report, u8 *raw_data, int size)
+{
+	struct picolcd_data *data = hid_get_drvdata(hdev);
+	char hexdata[25];
+	int i;
+
+	if (data == NULL)
+		return 1;
+
+	for (i = 0; i < sizeof(hexdata) / 2; i++)
+		sprintf(hexdata+2*i, "%02hhx", raw_data[i]);
+	if (size >= sizeof(hexdata)/2) {
+		hexdata[sizeof(hexdata)-4] = '.';
+		hexdata[sizeof(hexdata)-3] = '.';
+		hexdata[sizeof(hexdata)-2] = '.';
+		hexdata[sizeof(hexdata)-1] = '\0';
+	} else
+		hexdata[size*2] = '\0';
+
+	switch (report->id) {
+	case REPORT_KEYPAD:
+		if (size == 3 && raw_data[0] == 0x11 && data->input_keys) {
+			return picolcd_raw_keypad(hdev, report, raw_data+1, size-1);
+		} else {
+			dbg_hid(PICOLCD_NAME " unsupported key event (%d bytes): 0x%s\n", size, hexdata);
+			break;
+		}
+		break;
+	case REPORT_VERSION:
+		if (size == 3)
+			dev_info(&hdev->dev, "Firmware version is %hd.%hd\n", raw_data[1], raw_data[2]);
+
+		spin_lock(&data->lock);
+		if (!(data->status & PICOLCD_READY_ALIVE)) {
+			data->status |= PICOLCD_READY_ALIVE;
+			spin_unlock(&data->lock);
+			complete_all(&data->ready);
+		} else
+			spin_unlock(&data->lock);
+		break;
+
+	default:
+		dbg_hid(PICOLCD_NAME " got raw event %d with length %d: %s\n", report->id, size, hexdata);
+		return 0;
+	}
+
+	return 1;
+}
+
+
+/*
+ * Create a group of attributes so that we can create and destroy them all
+ * at once.
+ */
+static struct attribute *picolcd_attrs[] = {
+	&dev_attr_fb_update_rate.attr,
+	&dev_attr_reset.attr,
+	NULL,	 /* need to NULL terminate the list of attributes */
+};
+
+/*
+ * An unnamed attribute group will put all of the attributes directly in
+ * the kobject directory.  If we specify a name, a subdirectory will be
+ * created for the attributes with the directory being the name of the
+ * attribute group.
+ */
+static const struct attribute_group picolcd_attr_group = {
+	.attrs = picolcd_attrs,
+};
+
+
+static int picolcd_probe(struct hid_device *hdev,
+		     const struct hid_device_id *id)
+{
+	struct picolcd_data *data;
+	struct input_dev *idev;
+	int i, error = -ENOMEM;
+	char name[12];
+
+	dbg_hid(PICOLCD_NAME " hardware probe...\n");
+
+	/*
+	 * Let's allocate the picolcd data structure, set some reasonable
+	 * defaults, and associate it with the device
+	 */
+	data = kzalloc(sizeof(struct picolcd_data), GFP_KERNEL);
+	if (data == NULL) {
+		dev_err(&hdev->dev, "can't allocate space for Minibox PicoLCD device data\n");
+		error = -ENOMEM;
+		goto err_no_cleanup;
+	}
+
+	spin_lock_init(&data->lock);
+	init_completion(&data->ready);
+	data->hdev = hdev;
+	hid_set_drvdata(hdev, data);
+
+	data->fb_bitmap = vmalloc(PICOLCDFB_SIZE);
+	if (data->fb_bitmap == NULL) {
+		dev_err(&hdev->dev, "can't get a free page for framebuffer\n");
+		error = -ENOMEM;
+		goto err_cleanup_data;
+	}
+
+	data->fb_vbitmap = kmalloc(PICOLCDFB_SIZE, GFP_KERNEL);
+	if (data->fb_vbitmap == NULL) {
+		dev_err(&hdev->dev, "can't alloc vbitmap image buffer\n");
+		error = -ENOMEM;
+		goto err_cleanup_fb_bitmap;
+	}
+
+	/* Parse the device reports and start it up */
+	error = hid_parse(hdev);
+	if (error) {
+		dev_err(&hdev->dev, "device report parse failed\n");
+		goto err_cleanup_fb_vbitmap;
+	}
+
+	error = hid_hw_start(hdev, HID_CONNECT_HIDINPUT);
+	if (error) {
+		dev_err(&hdev->dev, "hardware start failed\n");
+		goto err_cleanup_fb_vbitmap;
+	}
+	dbg_hid(PICOLCD_NAME " claimed: %d\n", hdev->claimed);
+
+	error = hdev->ll_driver->open(hdev);
+	if (error) {
+		dev_err(&hdev->dev, "failed to open input interrupt pipe for key and IR events\n");
+		goto err_cleanup_hid_hw;
+	}
+
+	/* Setup input device */
+	idev = input_allocate_device();
+	if (idev == NULL) {
+		dev_err(&hdev->dev, "failed to allocate input device");
+		error = -ENOMEM;
+		goto err_cleanup_hid_ll;
+	}
+	input_set_drvdata(idev, hdev);
+	memcpy(data->keycode, def_keymap, sizeof(def_keymap));
+	idev->name = hdev->name;
+	idev->phys = hdev->phys;
+	idev->uniq = hdev->uniq;
+	idev->id.bustype = hdev->bus;
+	idev->id.vendor  = hdev->vendor;
+	idev->id.product = hdev->product;
+	idev->id.version = hdev->version;
+	idev->dev.parent = hdev->dev.parent;
+	idev->keycode     = &data->keycode;
+	idev->keycodemax  = PICOLCD_KEYS;
+	idev->keycodesize = sizeof(int);
+	input_set_capability(idev, EV_MSC, MSC_SCAN);
+	set_bit(EV_REP, idev->evbit);
+	for (i = 0; i < PICOLCD_KEYS; i++) {
+		int key = ((int *)idev->keycode)[i];
+		if (key < KEY_MAX && key >= 0)
+			input_set_capability(idev, EV_KEY, key);
+	}
+	error = input_register_device(idev);
+	if (error) {
+		dev_err(&hdev->dev, "error registering the input device");
+		input_free_device(idev);
+		goto err_cleanup_hid_ll;
+	}
+	data->input_keys = idev;
+
+	/* Set up the framebuffer device */
+	data->fb_update_rate = PICOLCDFB_UPDATE_RATE_DEFAULT;
+	data->fb_defio = picolcd_fb_defio;
+	data->fb_info = framebuffer_alloc(0, &hdev->dev);
+	if (data->fb_info == NULL) {
+		dev_err(&hdev->dev, "failed to allocate a framebuffer\n");
+		error = -ENOMEM;
+		goto err_cleanup_input_keys;
+	}
+
+	data->fb_info->fbdefio = &data->fb_defio;
+	data->fb_info->screen_base = (char __force __iomem *) data->fb_bitmap;
+	data->fb_info->fbops = &picolcdfb_ops;
+	data->fb_info->var = picolcdfb_var;
+	data->fb_info->fix = picolcdfb_fix;
+	data->fb_info->fix.smem_len = PICOLCDFB_SIZE;
+	data->fb_info->par = data;
+	data->fb_info->flags = FBINFO_FLAG_DEFAULT;
+	fb_deferred_io_init(data->fb_info);
+
+	error = register_framebuffer(data->fb_info);
+	if (error < 0) {
+		dev_err(&hdev->dev, "failed to register framebuffer\n");
+		fb_deferred_io_cleanup(data->fb_info);
+		framebuffer_release(data->fb_info);
+		goto err_cleanup_input_keys;
+	} else
+		error = 0;
+
+	snprintf(name, sizeof(name), "fb%d", data->fb_info->node);
+	data->lcd = lcd_device_register(name, &hdev->dev, data, &picolcd_lcdops);
+	if (IS_ERR(data->lcd)) {
+		dev_err(&hdev->dev, "failed to register LCD\n");
+		error = PTR_ERR(data->lcd);
+		goto err_cleanup_fb;
+	}
+	data->lcd->props.max_contrast = 0x0ff;
+	data->lcd_contrast = 0xe5;
+
+	data->backlight = backlight_device_register(name, &hdev->dev, data, &picolcd_blops);
+	if (IS_ERR(data->backlight)) {
+		dev_err(&hdev->dev, "failed to register backlight\n");
+		error = PTR_ERR(data->backlight);
+		goto err_cleanup_lcd;
+	}
+	data->backlight->props.max_brightness = 0x0ff;
+	data->backlight->props.brightness     = 0xff;
+	data->lcd_brightness                  = 0xff;
+
+	dbg_hid(PICOLCD_NAME " waiting for device to activate\n");
+	if (!picolcd_reset(hdev)) {
+		dbg_hid(PICOLCD_NAME " initialized\n");
+	} else
+		dev_warn(&hdev->dev, "hasn't responded yet, forging ahead with initialization\n");
+
+	picolcd_fb_reset(hdev, 1);
+
+	/* Add the sysfs attributes */
+	error = sysfs_create_group(&(hdev->dev.kobj), &picolcd_attr_group);
+	if (error) {
+		dev_err(&hdev->dev, "failed to create sysfs group attributes\n");
+		goto err_cleanup_bl;
+	}
+
+	dbg_hid(PICOLCD_NAME " activated and initialized\n");
+	return 0;
+
+
+err_cleanup_bl:
+	backlight_device_unregister(data->backlight);
+err_cleanup_lcd:
+	lcd_device_unregister(data->lcd);
+err_cleanup_fb:
+	unregister_framebuffer(data->fb_info);
+err_cleanup_input_keys:
+	input_unregister_device(data->input_keys);
+err_cleanup_hid_ll:
+	hdev->ll_driver->close(hdev);
+err_cleanup_hid_hw:
+	hid_hw_stop(hdev);
+err_cleanup_fb_vbitmap:
+	kfree(data->fb_vbitmap);
+err_cleanup_fb_bitmap:
+	vfree(data->fb_bitmap);
+err_cleanup_data:
+	kfree(data);
+err_no_cleanup:
+	hid_set_drvdata(hdev, NULL);
+
+	return error;
+}
+
+static void picolcd_remove(struct hid_device *hdev)
+{
+	struct picolcd_data *data = hid_get_drvdata(hdev);
+
+	dbg_hid(PICOLCD_NAME " hardware remove...\n");
+	sysfs_remove_group(&(hdev->dev.kobj), &picolcd_attr_group);
+
+	hdev->ll_driver->close(hdev);
+	hid_hw_stop(hdev);
+
+	/* Clean up the framebuffer */
+	backlight_device_unregister(data->backlight);
+	lcd_device_unregister(data->lcd);
+	unregister_framebuffer(data->fb_info);
+
+	/* Get the internal picolcd data buffer */
+	input_unregister_device(data->input_keys);
+
+	vfree(data->fb_bitmap);
+	kfree(data->fb_vbitmap);
+
+	/* Finally, clean up the picolcd data itself */
+	kfree(data);
+}
+
+static const struct hid_device_id picolcd_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_PICOLCD) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, picolcd_devices);
+
+static struct hid_driver picolcd_driver = {
+	.name =          "hid-picolcd",
+	.id_table =      picolcd_devices,
+	.probe =         picolcd_probe,
+	.remove =        picolcd_remove,
+	.raw_event =     picolcd_raw_event,
+};
+
+static int __init picolcd_init(void)
+{
+	return hid_register_driver(&picolcd_driver);
+}
+
+static void __exit picolcd_exit(void)
+{
+	hid_unregister_driver(&picolcd_driver);
+}
+
+module_init(picolcd_init);
+module_exit(picolcd_exit);
+MODULE_DESCRIPTION("Minibox graphics PicoLCD Driver");
+MODULE_LICENSE("GPL");
--
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[PATCH 2/3] hid: add suspend/resume hooks for hid drivers

[Bruno Prémont]

Add suspend/resume hooks for HID drivers so these can do some
additional state adjustment when device gets suspended/resumed.

This patch calls these hooks from usbhid suspend/resume functions,
only calling suspend on plain suspend, not autosuspend.
(it might be worth adding an autosuspend parameter to suspend
hook and calling suspend in both cases)

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
---
 drivers/hid/hid-core.c              |   19 ++-
 include/linux/hid.h                 |    8 +
 2 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index e2997a8..8ad1a98 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -1272,6 +1272,11 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message)
 		}
 
 	} else {
+		if (hid->driver && hid->driver->suspend) {
+			status = hid->driver->suspend(hid);
+			if (status < 0)
+				return status;
+		}
 		spin_lock_irq(&usbhid->lock);
 		set_bit(HID_REPORTED_IDLE, &usbhid->iofl);
 		spin_unlock_irq(&usbhid->lock);
@@ -1326,6 +1331,11 @@ static int hid_resume(struct usb_interface *intf)
 		hid_io_error(hid);
 	usbhid_restart_queues(usbhid);
 
+	if (hid->driver && hid->driver->resume) {
+		int ret = hid->driver->resume(hid);
+		if (ret < 0 && status == 0)
+			status = ret;
+	}
 	dev_dbg(&intf->dev, "resume status %d\n", status);
 	return 0;
 }
@@ -1334,9 +1344,16 @@ static int hid_reset_resume(struct usb_interface *intf)
 {
 	struct hid_device *hid = usb_get_intfdata(intf);
 	struct usbhid_device *usbhid = hid->driver_data;
+	int status;
 
 	clear_bit(HID_REPORTED_IDLE, &usbhid->iofl);
-	return hid_post_reset(intf);
+	status = hid_post_reset(intf);
+	if (hid->driver && hid->driver->reset_resume) {
+		int ret = hid->driver->reset_resume(hid);
+		if (ret < 0 && status == 0)
+			status = ret;
+	}
+	return status;
 }
 
 #endif /* CONFIG_PM */
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 8709365..b4409f1 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -589,6 +589,9 @@ struct hid_usage_id {
  * @report_fixup: called before report descriptor parsing (NULL means nop)
  * @input_mapping: invoked on input registering before mapping an usage
  * @input_mapped: invoked on input registering after mapping an usage
+ * @suspend: invoked on suspend (NULL means nop)
+ * @resume: invoked on resume if device was not reset (NULL means nop)
+ * @reset_resume: invoked on resume if device was reset (NULL means nop)
  *
  * raw_event and event should return 0 on no action performed, 1 when no
  * further processing should be done and negative on error
@@ -629,6 +632,11 @@ struct hid_driver {
 	int (*input_mapped)(struct hid_device *hdev,
 			struct hid_input *hidinput, struct hid_field *field,
 			struct hid_usage *usage, unsigned long **bit, int *max);
+#ifdef CONFIG_PM
+	int (*suspend)(struct hid_device *hdev);
+	int (*resume)(struct hid_device *hdev);
+	int (*reset_resume)(struct hid_device *hdev);
+#endif
 /* private: */
 	struct device_driver driver;
 };

Re: [PATCH 2/3] hid: add suspend/resume hooks for hid drivers

[Oliver Neukum]

Am Mittwoch, 24. Februar 2010 17:01:12 schrieb Bruno Prémont:
> Add suspend/resume hooks for HID drivers so these can do some
> additional state adjustment when device gets suspended/resumed.
> 
> This patch calls these hooks from usbhid suspend/resume functions,
> only calling suspend on plain suspend, not autosuspend.
> (it might be worth adding an autosuspend parameter to suspend
> hook and calling suspend in both cases)

This is quite dirty. A driver that was autosuspended may be non-auto resumed.
Secondly, do you really want to call the hook for reset_resume() if
hid_post_reset() has failed?

	Regards
		Oliver

Re: [PATCH 2/3] hid: add suspend/resume hooks for hid drivers

[Bruno Prémont]

On Thu, 25 February 2010 Oliver Neukum <oliver@neukum.org> wrote:
> Am Mittwoch, 24. Februar 2010 17:01:12 schrieb Bruno Prémont:
> > Add suspend/resume hooks for HID drivers so these can do some
> > additional state adjustment when device gets suspended/resumed.
> > 
> > This patch calls these hooks from usbhid suspend/resume functions,
> > only calling suspend on plain suspend, not autosuspend.
> > (it might be worth adding an autosuspend parameter to suspend
> > hook and calling suspend in both cases)
> 
> This is quite dirty.

Yeah, it covers what I did need (at least for success path). For the
rest I was expecting feedback (and probably should have labeled the
patch RFC)

> A driver that was autosuspended may be non-auto resumed. Secondly, do
> you really want to call the hook for reset_resume() if
> hid_post_reset() has failed?

Possibly not though depending on why hid_post_reset failed the first
USB operation would fail as well, thus it would fall under "normal"
error conditions for the driver...

Opinion of USB/HID experts is welcome!

> 	Regards
> 		Oliver

Thanks for the review!

Regards,
Bruno

[PATCH 3/3] hid-picolcd: make use of new suspend/resume hooks

[Bruno Prémont]

Make use of new suspend/resume hooks to disable backlight on suspend
and restore backlight on simple resume or backlight, contrast and
framebuffer content on reset-resume.

Signed-off-by: Bruno Prémont <bonbons-ud5FBsm0p/xEiooADzr8i9i2O/JbrIOy@public.gmane.org>
Cc: Nicu Pavel <npavel-VxACSXvuqMTQT0dZR+AlfA@public.gmane.org>
---
 drivers/hid/hid-picolcd.c           |   45 +++
 1 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index e69de29..90f6be5 100644
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -833,6 +833,46 @@
 };
 
 
+#ifdef CONFIG_PM
+static int picolcd_suspend(struct hid_device *hdev)
+{
+	struct picolcd_data *data = hid_get_drvdata(hdev);
+	int bl_power = data->lcd_power;
+
+	data->backlight->props.power = FB_BLANK_POWERDOWN;
+	picolcd_set_brightness(data->backlight);
+	data->lcd_power = data->backlight->props.power = bl_power;
+	dbg_hid(PICOLCD_NAME " device ready for suspend, lcd_power=%d\n", bl_power);
+	return 0;
+}
+
+static int picolcd_resume(struct hid_device *hdev)
+{
+	struct picolcd_data *data = hid_get_drvdata(hdev);
+	int ret;
+	ret = picolcd_set_brightness(data->backlight);
+	if (ret)
+		dbg_hid(PICOLCD_NAME " restoring brightness failed: %d\n", ret);
+	ret = picolcd_set_contrast(data->lcd, data->lcd_contrast);
+	if (ret)
+		dbg_hid(PICOLCD_NAME " restoring contrast failed: %d\n", ret);
+	return 0;
+}
+
+static int picolcd_reset_resume(struct hid_device *hdev)
+{
+	int ret;
+	ret = picolcd_reset(hdev);
+	if (ret)
+		dbg_hid(PICOLCD_NAME " resetting our device failed: %d\n", ret);
+	ret = picolcd_fb_reset(hdev, 0);
+	if (ret)
+		dbg_hid(PICOLCD_NAME " restoring framebuffer content failed: %d\n", ret);
+	return 0;
+}
+#endif
+
+
 static int picolcd_probe(struct hid_device *hdev,
 		     const struct hid_device_id *id)
 {
@@ -1057,6 +1097,11 @@
 	.probe =         picolcd_probe,
 	.remove =        picolcd_remove,
 	.raw_event =     picolcd_raw_event,
+#ifdef CONFIG_PM
+	.suspend =       picolcd_suspend,
+	.resume =        picolcd_resume,
+	.reset_resume =  picolcd_reset_resume,
+#endif
 };
 
 static int __init picolcd_init(void)
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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Jiri Kosina]

On Wed, 24 Feb 2010, Bruno Prémont wrote:

> +config HID_PICOLCD
> +	tristate "Minibox PicoLCD (graphic version)"
> +	depends on FB
> +	select FB_DEFERRED_IO
> +	select FB_SYS_FILLRECT
> +	select FB_SYS_COPYAREA
> +	select FB_SYS_IMAGEBLIT
> +	select FB_SYS_FOPS
> +	select BACKLIGHT_LCD_SUPPORT
> +	select BACKLIGHT_CLASS_DEVICE
> +	select LCD_CLASS_DEVICE

I guess you need dependency on USB_HID as well, right?

> --- a/drivers/hid/hid-picolcd.c
> +++ b/drivers/hid/hid-picolcd.c
> @@ -0,0 +1,1075 @@
> +/***************************************************************************
> + *   Copyright (C) 2010 by Bruno Prémont <bonbons@linux-vserver.org>       *
> + *                                                                         *
> + *   Based on Logitech G13 driver (v0.4)                                   *
> + *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard-qcTL/1vZYtg@public.gmane.orgedu>   *
> + *                                                                         *
> + *   This program is free software: you can redistribute it and/or modify  *
> + *   it under the terms of the GNU General Public License as published by  *
> + *   the Free Software Foundation, either version 2 of the License.        *

I support removing the 'or any later' clause, but I think your version has 
the grammar wrong :)


> +/* 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;
> +
> +	spin_lock(&data->lock);
> +	if (!(data->status & PICOLCD_READY_FB)) {
> +		spin_unlock(&data->lock);
> +		picolcd_fb_reset(data->hdev, 0);
> +	} else
> +		spin_unlock(&data->lock);

Please put the brackets to the else branch as well.

Also, it'd be great if the framebuffer part would get Ack from someone 
more familiar with framebuffer code than me.

Thanks,

-- 
Jiri Kosina
SUSE Labs, Novell Inc.
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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Bruno Prémont]

On Thu, 25 February 2010 Jiri Kosina <jkosina-AlSwsSmVLrQ@public.gmane.org> wrote:
> On Wed, 24 Feb 2010, Bruno Prémont wrote:
> 
> > +config HID_PICOLCD
> > +	tristate "Minibox PicoLCD (graphic version)"
> > +	depends on FB
> > +	select FB_DEFERRED_IO
> > +	select FB_SYS_FILLRECT
> > +	select FB_SYS_COPYAREA
> > +	select FB_SYS_IMAGEBLIT
> > +	select FB_SYS_FOPS
> > +	select BACKLIGHT_LCD_SUPPORT
> > +	select BACKLIGHT_CLASS_DEVICE
> > +	select LCD_CLASS_DEVICE
> 
> I guess you need dependency on USB_HID as well, right?

Yep, will add

> > --- a/drivers/hid/hid-picolcd.c
> > +++ b/drivers/hid/hid-picolcd.c
> > @@ -0,0 +1,1075 @@
> > +/***************************************************************************
> > + *   Copyright (C) 2010 by Bruno Prémont <bonbons@linux-vserver.org>       *
> > + *                                                                         *
> > + *   Based on Logitech G13 driver (v0.4)                                   *
> > + *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard-Ef8Xd5ARO5Q@public.gmane.orgu.edu>   *
> > + *                                                                         *
> > + *   This program is free software: you can redistribute it and/or modify  *
> > + *   it under the terms of the GNU General Public License as published by  *
> > + *   the Free Software Foundation, either version 2 of the License.        *
> 
> I support removing the 'or any later' clause, but I think your
> version has the grammar wrong :)

Oops, will fix

> > +/* 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;
> > +
> > +	spin_lock(&data->lock);
> > +	if (!(data->status & PICOLCD_READY_FB)) {
> > +		spin_unlock(&data->lock);
> > +		picolcd_fb_reset(data->hdev, 0);
> > +	} else
> > +		spin_unlock(&data->lock);
> 
> Please put the brackets to the else branch as well.

Ok, will add the brackets while switching from spin_(un)lock to
spin_(un)lock_irq{save|restore}.

> Also, it'd be great if the framebuffer part would get Ack from
> someone more familiar with framebuffer code than me.

I would appreciate such one as well, especially regarding the
deferredio part and the more advanced fb use. For now I only tested
read/write from /dev/fbx.


For the two sysfs attributes I currently use, the 'reset' one shall
probably be moved to debugfs (I would like to place it under
/sys/kernel/debug/hid/$device/ next to rdesc and event).

By the way, I'm wondering why event does not list any of the reports
coming from my device though as I understand the code it should be
doing that before my raw_event function gets called...

The one for deferredio refresh rate should ideally go below fb device
(and I guess that might also be of use for other users of deferredio)

Thanks for the review,
Bruno
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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Jiri Kosina]

On Thu, 25 Feb 2010, Bruno Prémont wrote:

> For the two sysfs attributes I currently use, the 'reset' one shall 
> probably be moved to debugfs (I would like to place it under 
> /sys/kernel/debug/hid/$device/ next to rdesc and event).

Yes, that would make sense.

( ... which reminds me to finally to the Documentation/ABI part in sync 
with respect to current HID code again ... )

> By the way, I'm wondering why event does not list any of the reports 
> coming from my device though as I understand the code it should be doing 
> that before my raw_event function gets called...

Sorry, what 'event' do you mean in 'event does not list any of the 
reports'?

Thanks,

-- 
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SUSE Labs, Novell Inc.
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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Bruno Prémont]

On Thu, 25 February 2010 Jiri Kosina <jkosina@suse.cz> wrote:
>
> On Thu, 25 Feb 2010, Bruno Prémont wrote:
> 
> > For the two sysfs attributes I currently use, the 'reset' one shall 
> > probably be moved to debugfs (I would like to place it under 
> > /sys/kernel/debug/hid/$device/ next to rdesc and event).
> 
> Yes, that would make sense.

So I will move it.

> ( ... which reminds me to finally to the Documentation/ABI part in
> sync with respect to current HID code again ... )
> 
> > By the way, I'm wondering why event does not list any of the
> > reports coming from my device though as I understand the code it
> > should be doing that before my raw_event function gets called...
> 
> Sorry, what 'event' do you mean in 'event does not list any of the 
> reports'?

Sorry, one 's' that got eaten between my brain and mail client. I
mean events file in debugfs.
For USB HID keyboard each key press generates "report dump" under
/sys/kernel/debug/hid/$device/events but for my PicoLCD I don't get
any entry in there. I'm wondering why.

Thanks,
Bruno

Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Bruno Prémont]

On Thu, 25 February 2010 Jiri Kosina <jkosina-AlSwsSmVLrQ@public.gmane.org> wrote:
> On Thu, 25 Feb 2010, Bruno Prémont wrote:
> 
> > For the two sysfs attributes I currently use, the 'reset' one shall 
> > probably be moved to debugfs (I would like to place it under 
> > /sys/kernel/debug/hid/$device/ next to rdesc and events).
> 
> Yes, that would make sense.

Hm, that works only when driver module gets loaded when USBHID device
is already plugged in.
When driver is registered and has it's probe function called on hotplug
it runs right before hid-core registers the debugfs entries.
As such hid_device's debug_dir is still NULL.

To get around this, in hid_add_device(), hid_debug_register() would
have to be called before device_add() instead of right after.

Is something like below acceptable? (from error handling point of view
it makes no difference...)

Thanks,
Bruno

file: drivers/hid/hid-core.c

 int hid_add_device(struct hid_device *hdev)
 {
         static atomic_t id = ATOMIC_INIT(0);
         int ret;
 
         if (WARN_ON(hdev->status & HID_STAT_ADDED))
                 return -EBUSY;
 
         /* we need to kill them here, otherwise they will stay allocated to
          * wait for coming driver */
         if (hid_ignore(hdev))
                 return -ENODEV;
 
         /* XXX hack, any other cleaner solution after the driver core
          * is converted to allow more than 20 bytes as the device name? */
         dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
                      hdev->vendor, hdev->product, atomic_inc_return(&id));
 
+        hid_debug_register(hdev, dev_name(&hdev->dev));
         ret = device_add(&hdev->dev);
         if (!ret)
                 hdev->status |= HID_STAT_ADDED;
 
-        hid_debug_register(hdev, dev_name(&hdev->dev));
 
         return ret;
 }
 EXPORT_SYMBOL_GPL(hid_add_device);

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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Alan Stern]

On Sat, 13 Mar 2010, Bruno [UTF-8] Prémont wrote:

> Is something like below acceptable? (from error handling point of view
> it makes no difference...)
> 
> Thanks,
> Bruno
> 
> file: drivers/hid/hid-core.c
> 
>  int hid_add_device(struct hid_device *hdev)
>  {
>          static atomic_t id = ATOMIC_INIT(0);
>          int ret;
>  
>          if (WARN_ON(hdev->status & HID_STAT_ADDED))
>                  return -EBUSY;
>  
>          /* we need to kill them here, otherwise they will stay allocated to
>           * wait for coming driver */
>          if (hid_ignore(hdev))
>                  return -ENODEV;
>  
>          /* XXX hack, any other cleaner solution after the driver core
>           * is converted to allow more than 20 bytes as the device name? */
>          dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
>                       hdev->vendor, hdev->product, atomic_inc_return(&id));
>  
> +        hid_debug_register(hdev, dev_name(&hdev->dev));
>          ret = device_add(&hdev->dev);
>          if (!ret)
>                  hdev->status |= HID_STAT_ADDED;
>  
> -        hid_debug_register(hdev, dev_name(&hdev->dev));
>  
>          return ret;
>  }

If the device_add() fails, you should undo the hid_debug_register() 
call.

Alan Stern

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[PATCH] hid: Register debugfs entries before adding device

[Bruno Prémont]

On Sat, 13 March 2010 Alan Stern <stern@rowland.harvard.edu> wrote:
> 
> If the device_add() fails, you should undo the hid_debug_register() 
> call.

Well I was wondering why hid_debug_register() was called no matter what
device_add() returned but didn't dig around what happened when
hid_add_device() would return an error.

Looking a few lines further, hid_remove_device() just unregisters debugfs
entries when status has HID_STAT_ADDED so it definitely makes sense to
do the proper cleanup (and hid_remove_device() is the only once calling
hid_debug_unregister())

So patch for both below:




Register debugfs entries before calling device_add() so debugfs entries
are already present when HID driver's probe function gets called on device
hotplug.
Also undo debugfs entry registration if device_add() fails so status
HID_STAT_ADDED and debugfs registration status remain consistent and
we don't leak the debugfs entries.

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
---


diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index eabe5f8..709b4d0 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1759,11 +1759,12 @@ int hid_add_device(struct hid_device *hdev)
 	dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
 		     hdev->vendor, hdev->product, atomic_inc_return(&id));
 
+	hid_debug_register(hdev, dev_name(&hdev->dev));
 	ret = device_add(&hdev->dev);
 	if (!ret)
 		hdev->status |= HID_STAT_ADDED;
-
-	hid_debug_register(hdev, dev_name(&hdev->dev));
+	else
+		hid_debug_unregister(hdev);
 
 	return ret;
 }
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Re: [PATCH] hid: Register debugfs entries before adding device

[Jiri Kosina]

On Sat, 13 Mar 2010, Bruno Prémont wrote:

> > If the device_add() fails, you should undo the hid_debug_register() 
> > call.
> 
> Well I was wondering why hid_debug_register() was called no matter what
> device_add() returned but didn't dig around what happened when
> hid_add_device() would return an error.
> 
> Looking a few lines further, hid_remove_device() just unregisters debugfs
> entries when status has HID_STAT_ADDED so it definitely makes sense to
> do the proper cleanup (and hid_remove_device() is the only once calling
> hid_debug_unregister())
> 
> So patch for both below:
> 
> 
> 
> 
> Register debugfs entries before calling device_add() so debugfs entries
> are already present when HID driver's probe function gets called on device
> hotplug.
> Also undo debugfs entry registration if device_add() fails so status
> HID_STAT_ADDED and debugfs registration status remain consistent and
> we don't leak the debugfs entries.
> 
> Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
> Cc: Alan Stern <stern@rowland.harvard.edu>
> ---
> 
> 
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index eabe5f8..709b4d0 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -1759,11 +1759,12 @@ int hid_add_device(struct hid_device *hdev)
>  	dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
>  		     hdev->vendor, hdev->product, atomic_inc_return(&id));
>  
> +	hid_debug_register(hdev, dev_name(&hdev->dev));
>  	ret = device_add(&hdev->dev);
>  	if (!ret)
>  		hdev->status |= HID_STAT_ADDED;
> -
> -	hid_debug_register(hdev, dev_name(&hdev->dev));
> +	else
> +		hid_debug_unregister(hdev);
>  
>  	return ret;

Applied, thank you Bruno.

-- 
Jiri Kosina
SUSE Labs, Novell Inc.

Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Rick L. Vinyard, Jr.]

Bruno Prémont wrote:
> The one for deferredio refresh rate should ideally go below fb device
> (and I guess that might also be of use for other users of deferredio)
>

I'm testing a patch now. I didn't expect anyone else would really need it,
but it does help with throttling bus traffic from userspace.

If it's in fbsysfs.c we can both eliminate it from our drivers.

-- 

Rick

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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Dmitry Torokhov]

On Thu, Feb 25, 2010 at 12:07:38PM +0100, Jiri Kosina wrote:
> On Wed, 24 Feb 2010, Bruno Prémont wrote:
> 
> > +/* 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;
> > +
> > +	spin_lock(&data->lock);
> > +	if (!(data->status & PICOLCD_READY_FB)) {
> > +		spin_unlock(&data->lock);
> > +		picolcd_fb_reset(data->hdev, 0);
> > +	} else
> > +		spin_unlock(&data->lock);
> 
> Please put the brackets to the else branch as well.
> 
Well, it looks like it can be rewritten as:

	spin_lock(&data->lock);
	need_reset = !(data->status & PICOLCD_READY_FB);
	spin_unlock(&data->lock);

	if (need_reset)
		picolcd_fb_reset(data->hdev, 0);

Which plainly shows that the locking here is bogus.

-- 
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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Oliver Neukum]

Am Mittwoch, 24. Februar 2010 17:00:49 schrieb Bruno Prémont:
> +static int picolcd_raw_event(struct hid_device *hdev,
> +               struct hid_report *report, u8 *raw_data, int size)
> +{
> +       struct picolcd_data *data = hid_get_drvdata(hdev);
> +       char hexdata[25];
> +       int i;
> +
> +       if (data == NULL)
> +               return 1;
> +
> +       for (i = 0; i < sizeof(hexdata) / 2; i++)
> +               sprintf(hexdata+2*i, "%02hhx", raw_data[i]);
> +       if (size >= sizeof(hexdata)/2) {
> +               hexdata[sizeof(hexdata)-4] = '.';
> +               hexdata[sizeof(hexdata)-3] = '.';
> +               hexdata[sizeof(hexdata)-2] = '.';
> +               hexdata[sizeof(hexdata)-1] = '\0';
> +       } else
> +               hexdata[size*2] = '\0';
> +
> +       switch (report->id) {
> +       case REPORT_KEYPAD:
> +               if (size == 3 && raw_data[0] == 0x11 && data->input_keys) {
> +                       return picolcd_raw_keypad(hdev, report, raw_data+1, size-1);
> +               } else {
> +                       dbg_hid(PICOLCD_NAME " unsupported key event (%d bytes): 0x%s\n", size, hexdata);
> +                       break;
> +               }
> +               break;
> +       case REPORT_VERSION:
> +               if (size == 3)
> +                       dev_info(&hdev->dev, "Firmware version is %hd.%hd\n", raw_data[1], raw_data[2]);
> +
> +               spin_lock(&data->lock);

If I recall correctly raw_event is called in interrupt. As you take a spinlock here,
the lock in code not called in interrupt must disable interrupts, or you may
deadlock.

	Regards
		Oliver
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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Rick L. Vinyard, Jr.]

Oliver Neukum wrote:
> Am Mittwoch, 24. Februar 2010 17:00:49 schrieb Bruno Prémont:
>> +static int picolcd_raw_event(struct hid_device *hdev,
>> +               struct hid_report *report, u8 *raw_data, int size)
>> +{
>> +       struct picolcd_data *data = hid_get_drvdata(hdev);
>> +       char hexdata[25];
>> +       int i;
>> +
>> +       if (data == NULL)
>> +               return 1;
>> +
>> +       for (i = 0; i < sizeof(hexdata) / 2; i++)
>> +               sprintf(hexdata+2*i, "%02hhx", raw_data[i]);
>> +       if (size >= sizeof(hexdata)/2) {
>> +               hexdata[sizeof(hexdata)-4] = '.';
>> +               hexdata[sizeof(hexdata)-3] = '.';
>> +               hexdata[sizeof(hexdata)-2] = '.';
>> +               hexdata[sizeof(hexdata)-1] = '\0';
>> +       } else
>> +               hexdata[size*2] = '\0';
>> +
>> +       switch (report->id) {
>> +       case REPORT_KEYPAD:
>> +               if (size == 3 && raw_data[0] == 0x11 &&
>> data->input_keys) {
>> +                       return picolcd_raw_keypad(hdev, report,
>> raw_data+1, size-1);
>> +               } else {
>> +                       dbg_hid(PICOLCD_NAME " unsupported key event (%d
>> bytes): 0x%s\n", size, hexdata);
>> +                       break;
>> +               }
>> +               break;
>> +       case REPORT_VERSION:
>> +               if (size == 3)
>> +                       dev_info(&hdev->dev, "Firmware version is
>> %hd.%hd\n", raw_data[1], raw_data[2]);
>> +
>> +               spin_lock(&data->lock);
>
> If I recall correctly raw_event is called in interrupt. As you take a
> spinlock here,
> the lock in code not called in interrupt must disable interrupts, or you
> may
> deadlock.
>

The issue, as I understand it is that non-interrupt code may obtain the
lock and then the interrupt code is executed... hence the deadlock and the
need to use spin_lock_irqsave() and spin_unlock_irqrestore().

If that is correct, is there any problem with the following approach?

The key difference is the replacement of spin_lock() with spin_trylock()
such that if the non-interrupt code has already obtained the lock, the
interrupt will not deadlock but instead take the else path and schedule a
framebuffer update at the next interval.

static void g13_fb_urb_completion(struct urb *urb)
{
	struct g13_data *data = urb->context;
	spin_unlock(&data->fb_urb_lock);
}

static int g13_fb_send(struct hid_device *hdev)
{
	struct usb_interface *intf;
	struct usb_device *usb_dev;
	struct g13_data *data = hid_get_g13data(hdev);

	struct usb_host_endpoint *ep;
	unsigned int pipe;
	int retval = 0;

	/*
	 * Try and lock the framebuffer urb to prevent access if we have
	 * submitted it. If we can't lock it we'll have to delay this update
	 * until the next framebuffer interval.
	 *
	 * Fortunately, we already have the infrastructure in place with the
	 * framebuffer deferred I/O driver to schedule the delayed update.
	 */
	if (likely(spin_trylock(&data->fb_urb_lock))) {
		/* Get the usb device to send the image on */
		intf = to_usb_interface(hdev->dev.parent);
		usb_dev = interface_to_usbdev(intf);

		pipe = usb_sndintpipe(usb_dev, 0x02);

		ep = usb_dev->ep_out[usb_pipeendpoint(pipe)];

		if (unlikely(!ep)) {
			spin_unlock(&data->fb_urb_lock);
			return -EINVAL;
		}

		pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
		usb_fill_int_urb(data->fb_urb, usb_dev, pipe, data->fb_vbitmap,
				 G13_VBITMAP_SIZE, g13_fb_urb_completion, NULL,
				 ep->desc.bInterval);
		data->fb_urb->context = data;
		data->fb_urb->actual_length = 0;

		retval = usb_submit_urb(data->fb_urb, GFP_NOIO);
		if (unlikely(retval < 0)) {
			/*
			 * We need to unlock the framebuffer urb lock since
			 * the urb submission failed and therefore
			 * g13_fb_urb_completion() won't be called.
			 */
			spin_unlock(&data->fb_urb_lock);
			return retval;
		}
	} else {
		schedule_delayed_work(&data->fb_info->deferred_work,
				      data->fb_defio.delay);
	}

	return retval;
}

Thanks,

-- 

Rick

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Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Oliver Neukum]

Am Mittwoch, 24. Februar 2010 22:44:53 schrieb Rick L. Vinyard, Jr.:
> The issue, as I understand it is that non-interrupt code may obtain the
> lock and then the interrupt code is executed... hence the deadlock and the
> need to use spin_lock_irqsave() and spin_unlock_irqrestore().

Yes.

> If that is correct, is there any problem with the following approach?

Why not always a workqueue or alternatively spin_lock_irq() when
you are not in interrupt? This approach seems needlessly complicated.

Secondly, when you hold a spinlock, you must use GFP_ATOMIC.
GFP_NOIO is insufficient.

	Regards
		Oliver

Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Jiri Kosina]

On Wed, 24 Feb 2010, Rick L. Vinyard, Jr. wrote:

> >> +static int picolcd_raw_event(struct hid_device *hdev,
> >> +               struct hid_report *report, u8 *raw_data, int size)
> >> +{
> >> +       struct picolcd_data *data = hid_get_drvdata(hdev);
> >> +       char hexdata[25];
> >> +       int i;
> >> +
> >> +       if (data == NULL)
> >> +               return 1;
> >> +
> >> +       for (i = 0; i < sizeof(hexdata) / 2; i++)
> >> +               sprintf(hexdata+2*i, "%02hhx", raw_data[i]);
> >> +       if (size >= sizeof(hexdata)/2) {
> >> +               hexdata[sizeof(hexdata)-4] = '.';
> >> +               hexdata[sizeof(hexdata)-3] = '.';
> >> +               hexdata[sizeof(hexdata)-2] = '.';
> >> +               hexdata[sizeof(hexdata)-1] = '\0';
> >> +       } else
> >> +               hexdata[size*2] = '\0';
> >> +
> >> +       switch (report->id) {
> >> +       case REPORT_KEYPAD:
> >> +               if (size == 3 && raw_data[0] == 0x11 &&
> >> data->input_keys) {
> >> +                       return picolcd_raw_keypad(hdev, report,
> >> raw_data+1, size-1);
> >> +               } else {
> >> +                       dbg_hid(PICOLCD_NAME " unsupported key event (%d
> >> bytes): 0x%s\n", size, hexdata);
> >> +                       break;
> >> +               }
> >> +               break;
> >> +       case REPORT_VERSION:
> >> +               if (size == 3)
> >> +                       dev_info(&hdev->dev, "Firmware version is
> >> %hd.%hd\n", raw_data[1], raw_data[2]);
> >> +
> >> +               spin_lock(&data->lock);
> >
> > If I recall correctly raw_event is called in interrupt. 

Yes, that is correct.

> The issue, as I understand it is that non-interrupt code may obtain the 
> lock and then the interrupt code is executed... hence the deadlock and 
> the need to use spin_lock_irqsave() and spin_unlock_irqrestore().

Exactly. All the spinlocks that are aquired in interrupt code-paths must 
be acquired with _irqsave()/_irqrestore() from the non-interrupt code to 
prevent exactly this kind of deadlock.
> 
> The key difference is the replacement of spin_lock() with spin_trylock()
> such that if the non-interrupt code has already obtained the lock, the
> interrupt will not deadlock but instead take the else path and schedule a
> framebuffer update at the next interval.

Why is _irqsave() and/or deferred work not enough? The aproach with 
_trylock() seems to be overly complicated for no good reason (I personally 
become very suspicious every time I see code that is using _trylock()).

[ by the way, Rick, are you planning to resubmit the G13 driver with 
incorporated feedback from the last review round? ]

Thanks,

-- 
Jiri Kosina
SUSE Labs, Novell Inc.

Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Rick L. Vinyard, Jr.]

Jiri Kosina wrote:
> On Wed, 24 Feb 2010, Rick L. Vinyard, Jr. wrote:
>
>> The key difference is the replacement of spin_lock() with spin_trylock()
>> such that if the non-interrupt code has already obtained the lock, the
>> interrupt will not deadlock but instead take the else path and schedule
>> a
>> framebuffer update at the next interval.
>
> Why is _irqsave() and/or deferred work not enough? The aproach with
> _trylock() seems to be overly complicated for no good reason (I personally
> become very suspicious every time I see code that is using _trylock()).
>

I was concerned about _irqsave() because the lock is split across two
functions to protect the urb after it is handed off to the usb subsystem
with usb_submit_urb(). It's locked in g13_fb_send() and unlocked in the
urb completion callback.

As for deferred work, the g13_fb_send() is the I/O portion of the deferred
framebuffer callback. I was concerned that without a lock one deferred
update could hand the urb off to the usb subsystem and a second could try
to access it before it was handed back to the driver.

In this case the _trylock() would fail and in the else patch we would
defer yet again until the next update cycle.

I took this approach because usb_interrupt_msg() couldn't be used from an
interrupt context, such as a resume hook because eventually down the chain
it does a wait_for_completion_timeout().

It has the added benefit of reusing the urb instead of creating a new one
for each framebuffer sent out, but that wasn't a reason... just a side
effect.

The downside is that I had to manage the urb.

One thing I could do is forget about directly calling g13_fb_send() from
any context and instead use the deferred framebuffer workqueue.

That's probably a simpler approach anyway.

> [ by the way, Rick, are you planning to resubmit the G13 driver with
> incorporated feedback from the last review round? ]
>

Yes. I just wanted to get the details of suspend/resume worked out before
resubmitting.

-- 

Rick

Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Dmitry Torokhov]

On Thu, Feb 25, 2010 at 08:34:42AM -0700, Rick L. Vinyard, Jr. wrote:
> Jiri Kosina wrote:
> > On Wed, 24 Feb 2010, Rick L. Vinyard, Jr. wrote:
> >
> >> The key difference is the replacement of spin_lock() with spin_trylock()
> >> such that if the non-interrupt code has already obtained the lock, the
> >> interrupt will not deadlock but instead take the else path and schedule
> >> a
> >> framebuffer update at the next interval.
> >
> > Why is _irqsave() and/or deferred work not enough? The aproach with
> > _trylock() seems to be overly complicated for no good reason (I personally
> > become very suspicious every time I see code that is using _trylock()).
> >
> 
> I was concerned about _irqsave() because the lock is split across two
> functions to protect the urb after it is handed off to the usb subsystem
> with usb_submit_urb(). It's locked in g13_fb_send() and unlocked in the
> urb completion callback.
> 
> As for deferred work, the g13_fb_send() is the I/O portion of the deferred
> framebuffer callback. I was concerned that without a lock one deferred
> update could hand the urb off to the usb subsystem and a second could try
> to access it before it was handed back to the driver.
> 
> In this case the _trylock() would fail and in the else patch we would
> defer yet again until the next update cycle.
> 

What you are looking for here is called test_and_set_bit(). Do not muddy
the waters with a lock.

-- 
Dmitry

Re: [PATCH 1/3] picolcd: driver for PicoLCD HID device

[Pavel Machek]

Hi!

> +#ifdef CONFIG_LOGO
> +/*
> + * This is a default logo to be loaded upon driver initialization
> + * replacing the default PicoLCD image loaded on device
> + * initialization. This is to provide the user a cue that the
> + * Linux driver is loaded and ready.
> + *
> + * This logo contains the text PicoLCD in the center with one penguin
> + * on each side of the text. The penguins are a 64x64 rendition of
> + * the default framebuffer 80x80 monochrome image scaled down and
> + * cleaned up to retain something that looks a little better than
> + * a simple scaling.
> + *
> + * This logo is a simple xbm image created in GIMP and exported.
> + * To view the image copy the following two #defines plus the
> + * picolcd_bits to an ASCII text file and save with extension
> + * .xbm, then open with GIMP or any other graphical editor
> + * such as eog that recognizes the .xbm format.
> + */
> +#define picolcd_width 256
> +#define picolcd_height 64
> +static const u8 picolcd_bits[PICOLCDFB_SIZE] = {
> +	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
> +	0xff, 0xff, 0xff, 0xf8, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf8, 0x1f, 0xff, 0xff, 0xff,

Please remove this. There are less ugly/shorter ways to tell the user
device is ready.
-- 
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html