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ecefae6db0
While there are a mix of things here, most of the stuff were written from Kernel developer's PoV. So, add them to the driver-api book. A follow up for this patch would be to move documents from there that are specific to sysadmins, adding them to the admin-guide. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Johan Hovold <johan@kernel.org> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
52 lines
1.5 KiB
ReStructuredText
52 lines
1.5 KiB
ReStructuredText
=============================
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USB 7-Segment Numeric Display
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=============================
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Manufactured by Delcom Engineering
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Device Information
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------------------
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USB VENDOR_ID 0x0fc5
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USB PRODUCT_ID 0x1227
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Both the 6 character and 8 character displays have PRODUCT_ID,
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and according to Delcom Engineering no queryable information
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can be obtained from the device to tell them apart.
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Device Modes
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------------
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By default, the driver assumes the display is only 6 characters
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The mode for 6 characters is:
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MSB 0x06; LSB 0x3f
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For the 8 character display:
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MSB 0x08; LSB 0xff
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The device can accept "text" either in raw, hex, or ascii textmode.
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raw controls each segment manually,
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hex expects a value between 0-15 per character,
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ascii expects a value between '0'-'9' and 'A'-'F'.
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The default is ascii.
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Device Operation
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----------------
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1. Turn on the device:
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echo 1 > /sys/bus/usb/.../powered
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2. Set the device's mode:
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echo $mode_msb > /sys/bus/usb/.../mode_msb
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echo $mode_lsb > /sys/bus/usb/.../mode_lsb
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3. Set the textmode:
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echo $textmode > /sys/bus/usb/.../textmode
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4. set the text (for example):
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echo "123ABC" > /sys/bus/usb/.../text (ascii)
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echo "A1B2" > /sys/bus/usb/.../text (ascii)
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echo -ne "\x01\x02\x03" > /sys/bus/usb/.../text (hex)
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5. Set the decimal places.
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The device has either 6 or 8 decimal points.
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to set the nth decimal place calculate 10 ** n
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and echo it in to /sys/bus/usb/.../decimals
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To set multiple decimals points sum up each power.
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For example, to set the 0th and 3rd decimal place
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echo 1001 > /sys/bus/usb/.../decimals
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