[PATCH] USB: input: wacom_sys.c: format OLED image in kernel

[PATCH] USB: input: wacom_sys.c: format OLED image in kernel

[Przemo Firszt]

This patch adds a new way of handling Wacom Intuos4 family OLEDs.
Previously the images had to be 'scrambled' by userland application. Now
the 'scrambling' is done in the kernel module, so user space can send
simple 64x32 pixels 4-bit grayscale (2 pixels per byte) 0,0 in top left corner
images straight to a wacom OLED sysfs entry. An example:

dd bs=1024 if=image_file \
of=/sys/bus/usb/drivers/wacom/[DevNo]/wacom_led/button[No]_formattedimg \
count=1

This patch greatly simplifies user space preparation of the image.
The raw image sysfs enties are still present to avoid breaking API.

Signed-off-by: Przemo Firszt <przemo@firszt.eu>
---
 Documentation/ABI/testing/sysfs-driver-wacom |  7 ++++
 drivers/input/tablet/wacom_sys.c             | 60 +++++++++++++++++++++++++---
 2 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-driver-wacom b/Documentation/ABI/testing/sysfs-driver-wacom
index 7fc7810..5b369a3 100644
--- a/Documentation/ABI/testing/sysfs-driver-wacom
+++ b/Documentation/ABI/testing/sysfs-driver-wacom
@@ -93,3 +93,10 @@ Description:
 		byte chunk encodes the image data for two consecutive lines on
 		the display. The low nibble of each byte contains the first
 		line, and the high nibble contains the second line.
+
+What:		/sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/button<n>_formattedimg
+Date:		September 2012
+Contact:	linux-input@vger.kernel.org
+Description:
+		A plain format entry to wacom OLED icons. 1024 byte, 64x32 pixel 4-bit gray image,
+		2 pixels per byte, 0,0 in top left corner.
diff --git a/drivers/input/tablet/wacom_sys.c b/drivers/input/tablet/wacom_sys.c
index 0d3219f..19c668d 100644
--- a/drivers/input/tablet/wacom_sys.c
+++ b/drivers/input/tablet/wacom_sys.c
@@ -654,11 +654,30 @@ static int wacom_led_control(struct wacom *wacom)
 
 	return retval;
 }
+static void wacom_scramble(__u8 *image)
+{
+	__u8 buf[1024];
+	int x, y, i;
+
+	memcpy(buf, image , 1024);
+
+	for (y = 0; y < 16; y++) {
+		for (x = 0; x < 32; x++) {
+			i = (2 * x) + (64 * y);
+			image[i] = (buf[63 - x + 64 * y] << 4) |
+					 (0x0F & (buf[31 - x + 64 * y]));
+			image[i + 1] = (0xF0 & buf[63 - x + 64 * y]) |
+					 (buf[31 - x + 64 * y] >> 4);
+		}
+	}
+}
 
-static int wacom_led_putimage(struct wacom *wacom, int button_id, const void *img)
+static int wacom_led_putimage(struct wacom *wacom, int button_id,
+				 const void *img, int f)
 {
 	unsigned char *buf;
 	int i, retval;
+	__u8 p[1024];
 
 	buf = kzalloc(259, GFP_KERNEL);
 	if (!buf)
@@ -672,11 +691,16 @@ static int wacom_led_putimage(struct wacom *wacom, int button_id, const void *im
 	if (retval < 0)
 		goto out;
 
+	memcpy(p, img , 1024);
+
+	if (f)
+		wacom_scramble(p);
+
 	buf[0] = WAC_CMD_ICON_XFER;
 	buf[1] = button_id & 0x07;
 	for (i = 0; i < 4; i++) {
 		buf[2] = i;
-		memcpy(buf + 3, img + i * 256, 256);
+		memcpy(buf + 3, p + i * 256, 256);
 
 		retval = wacom_set_report(wacom->intf, 0x03, WAC_CMD_ICON_XFER,
 					  buf, 259, WAC_CMD_RETRIES);
@@ -772,7 +796,7 @@ DEVICE_LUMINANCE_ATTR(status1, hlv);
 DEVICE_LUMINANCE_ATTR(buttons, img_lum);
 
 static ssize_t wacom_button_image_store(struct device *dev, int button_id,
-					const char *buf, size_t count)
+					const char *buf, size_t count, int f)
 {
 	struct wacom *wacom = dev_get_drvdata(dev);
 	int err;
@@ -782,7 +806,7 @@ static ssize_t wacom_button_image_store(struct device *dev, int button_id,
 
 	mutex_lock(&wacom->lock);
 
-	err = wacom_led_putimage(wacom, button_id, buf);
+	err = wacom_led_putimage(wacom, button_id, buf, f);
 
 	mutex_unlock(&wacom->lock);
 
@@ -793,7 +817,7 @@ static ssize_t wacom_button_image_store(struct device *dev, int button_id,
 static ssize_t wacom_btnimg##BUTTON_ID##_store(struct device *dev,	\
 	struct device_attribute *attr, const char *buf, size_t count)	\
 {									\
-	return wacom_button_image_store(dev, BUTTON_ID, buf, count);	\
+	return wacom_button_image_store(dev, BUTTON_ID, buf, count, 0);	\
 }									\
 static DEVICE_ATTR(button##BUTTON_ID##_rawimg, S_IWUSR,			\
 		   NULL, wacom_btnimg##BUTTON_ID##_store)
@@ -807,6 +831,24 @@ DEVICE_BTNIMG_ATTR(5);
 DEVICE_BTNIMG_ATTR(6);
 DEVICE_BTNIMG_ATTR(7);
 
+#define DEVICE_BTNIMG_FORMATTED_ATTR(BUTTON_ID)				\
+static ssize_t wacom_btnimg##BUTTON_ID##_store_formatted(struct device *dev,\
+	struct device_attribute *attr, const char *buf, size_t count)	\
+{									\
+	return wacom_button_image_store(dev, BUTTON_ID, buf, count, 1);	\
+}									\
+static DEVICE_ATTR(button##BUTTON_ID##_formattedimg, S_IWUSR,		\
+		   NULL, wacom_btnimg##BUTTON_ID##_store_formatted)
+
+DEVICE_BTNIMG_FORMATTED_ATTR(0);
+DEVICE_BTNIMG_FORMATTED_ATTR(1);
+DEVICE_BTNIMG_FORMATTED_ATTR(2);
+DEVICE_BTNIMG_FORMATTED_ATTR(3);
+DEVICE_BTNIMG_FORMATTED_ATTR(4);
+DEVICE_BTNIMG_FORMATTED_ATTR(5);
+DEVICE_BTNIMG_FORMATTED_ATTR(6);
+DEVICE_BTNIMG_FORMATTED_ATTR(7);
+
 static struct attribute *cintiq_led_attrs[] = {
 	&dev_attr_status_led0_select.attr,
 	&dev_attr_status_led1_select.attr,
@@ -831,6 +873,14 @@ static struct attribute *intuos4_led_attrs[] = {
 	&dev_attr_button5_rawimg.attr,
 	&dev_attr_button6_rawimg.attr,
 	&dev_attr_button7_rawimg.attr,
+	&dev_attr_button0_formattedimg.attr,
+	&dev_attr_button1_formattedimg.attr,
+	&dev_attr_button2_formattedimg.attr,
+	&dev_attr_button3_formattedimg.attr,
+	&dev_attr_button4_formattedimg.attr,
+	&dev_attr_button5_formattedimg.attr,
+	&dev_attr_button6_formattedimg.attr,
+	&dev_attr_button7_formattedimg.attr,
 	NULL
 };
 
-- 
1.7.12

Re: [PATCH] USB: input: wacom_sys.c: format OLED image in kernel

[Dmitry Torokhov]

Hi Przemo,

On Sun, Sep 09, 2012 at 03:37:18PM -0400, Przemo Firszt wrote:
> This patch adds a new way of handling Wacom Intuos4 family OLEDs.
> Previously the images had to be 'scrambled' by userland application. Now
> the 'scrambling' is done in the kernel module, so user space can send
> simple 64x32 pixels 4-bit grayscale (2 pixels per byte) 0,0 in top left corner
> images straight to a wacom OLED sysfs entry. An example:
> 
> dd bs=1024 if=image_file \
> of=/sys/bus/usb/drivers/wacom/[DevNo]/wacom_led/button[No]_formattedimg \
> count=1
> 
> This patch greatly simplifies user space preparation of the image.
> The raw image sysfs enties are still present to avoid breaking API.

I do not not believe that we should add code to the kernel for tasks that
can be just as easily performed in userspace.

Thanks!

-- 
Dmitry

Re: [PATCH] USB: input: wacom_sys.c: format OLED image in kernel

[Przemo Firszt]

Dnia 4 Października 2012, 8:25 am, Cz, Dmitry Torokhov napisał(a):
> Hi Przemo,
Hi Dmitry,
>
> On Sun, Sep 09, 2012 at 03:37:18PM -0400, Przemo Firszt wrote:
>> This patch adds a new way of handling Wacom Intuos4 family OLEDs.
>> Previously the images had to be 'scrambled' by userland application. Now
>> the 'scrambling' is done in the kernel module, so user space can send
>> simple 64x32 pixels 4-bit grayscale (2 pixels per byte) 0,0 in top left
>> corner
>> images straight to a wacom OLED sysfs entry. An example:
>>
>> dd bs=1024 if=image_file \
>> of=/sys/bus/usb/drivers/wacom/[DevNo]/wacom_led/button[No]_formattedimg
>> \
>> count=1
>>
>> This patch greatly simplifies user space preparation of the image.
>> The raw image sysfs enties are still present to avoid breaking API.
>
> I do not not believe that we should add code to the kernel for tasks that
> can be just as easily performed in userspace.
>
> Thanks!
>
> --
> Dmitry
>
OK, thanks for the explanation!

-- 
Regards,
Przemo Firszt