Hi Supid, On Sat, Dec 06, 2014 at 03:39:33PM +0530, Sudip Mukherjee wrote: > On Sat, Dec 06, 2014 at 09:41:08AM +0100, Willy Tarreau wrote: > > Hi Sudip, > > > > [ CCing Mariusz who's currently cleaning up the driver ] > > > > On Tue, Dec 02, 2014 at 01:32:14PM +0530, Sudip Mukherjee wrote: > > > Hi, > > > I have been looking at your panel driver, and am attaching a 20x4 > > > alphanueric > > > lcd to it. Will start testing it in a few days as and when I get time. > > > Looks > > > like, it is receiving mostly checkpatch and sparse cleanups. > > > > yes mostly. > > > > > Just wanted your opinion on few things I was thinking: > > > 1) Number of lines you have fixed to 2 and 40 char per line. since I am > > > going to connect 20x4 , i need to remember that after displaying 20 > > > character in 1st line, next char will come to 3rd line. instead why > > > don't we make the option of number of line to 4 ? > > > > Feel free to do so. I never had the luck to own a 4-line LCD so this > > was never even planned. And yes, I remember something about 4-line LCDs > > using tricks such as 2x40 addressing being split into 4x20. > well, i work in a company which is in embedded training, so i have access to > few hardware, and for this i can have 16x2 and 20x4 lcd, but no serial lcd > ... :(
Setting the height to 4 is not going to make it work properly - due to the way the display is working internally. I also own one in 4x20 size and after I get done with the cleaning stuff, I'm going to add proper support for it. > > > > > 2) The lcd commands you are writing to the lcd in an escape sequence > > > while writing to the lcd. Instead of that why don't we use ioctl for > > > lcd commands, and writing to the device will involve only sending data > > > to lcd ? > > > > Because you cannot send that from a script. It's just as if you had to use > > an ioctl to clear your terminal, inverse its video or to move its cursor, > > it would not be very convenient. > yes, ioctl will not be possible from script. but here in India, we will > usually use c code for embedded systems, on very rare occassion we will use > scripts. and we will be using open(), read(), write(), ioctl() and close() > system calls from our projects. > here, we can have both methods in the code. if someone is using escape > sequence - that will work, and we can also have the ioctl for the same > purpose. > > > > > 3) You have given fixed minor number in your code. Any problem if we > > > make it dynamic ? > > > > No objection, but I think we should keep a config option to bind to the > > old minor. The rationale behind this is that this driver is mostly used > > in embedded systems with a fixed /dev. > ok. but one doubt: won't misc_register create the /dev entry automatically ? > > thanks > sudip > > > > > 4) For now I am only attaching a LCD, but I also want to attach a > > > keypad to it. Can you please let me know about the schematic of the > <snip> > > init -> > > select_in -> > > > > And here's the module load command I used to run : > > insmod /tmp/panel-0.8.0.o parport=0 lcd_enabled=2 keypad_enabled=1 > > lcd_width=16 lcd_hwidth=16 lcd_height=2 > > > > Hoping this helps, > > Willy > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
