Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752273AbaLFK3A (ORCPT ); Sat, 6 Dec 2014 05:29:00 -0500 Received: from mail-wi0-f174.google.com ([209.85.212.174]:63404 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751523AbaLFK27 (ORCPT ); Sat, 6 Dec 2014 05:28:59 -0500 Date: Sat, 6 Dec 2014 11:28:54 +0100 From: Mariusz Gorski To: Sudip Mukherjee Cc: Willy Tarreau , Greg Kroah-Hartman , LKML Subject: Re: staging: panel: suggestions needed Message-ID: <20141206102853.GB2959@firebird> References: <20141202080214.GA4762@sudip-PC> <20141206084108.GA3404@1wt.eu> <20141206100933.GA7141@sudip-PC> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141206100933.GA7141@sudip-PC> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > > > 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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/