Dear Greg, Geert, > I guess you mean the forward declaration of ioctrl()? > No, they should include <sys/ioctl.h> instead. Right. Adding "#include <sys/ioctl.h>" to Greg's sample code causes a compilation error. > > I saw the code above, I thought I wouldn't write such code normally. > Why not? Is it normal to declare ioctl() without "#include <sys/ioctl.h>" ? Thanks & Best Regards, Yuusuke Ashiduka <ashiduka@xxxxxxxxxxx> Embedded System Development Dept. Embedded System Development Div. FUJITSU COMPUTER TECHNOLOGIES Ltd. > -----Original Message----- > From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > Sent: Thursday, March 12, 2020 6:03 PM > To: Torii, Kenichi/鳥居 健一 <torii.ken1@xxxxxxxxxxx> > Cc: gregkh@xxxxxxxxxxxxxxxxxxx; erosca@xxxxxxxxxxxxxx; > linux-serial@xxxxxxxxxxxxxxx; linux-renesas-soc@xxxxxxxxxxxxxxx; > wsa+renesas@xxxxxxxxxxxxxxxxxxxx; > yoshihiro.shimoda.uh@xxxxxxxxxxx; uli+renesas@xxxxxxxx; > george_davis@xxxxxxxxxx; andrew_gabbasov@xxxxxxxxxx; > jiada_wang@xxxxxxxxxx; yuichi.kusakabe@xxxxxxxxxxxxx; > yasano@xxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > jslaby@xxxxxxxx; yohhei.fukui@xxxxxxxxxxxxx; Ashizuka, Yuusuke/ > 芦塚 雄介 <ashiduka@xxxxxxxxxxx>; magnus.damm@xxxxxxxxx > Subject: Re: [PATCH] serial: sh-sci: Support custom speed setting > > Hi Torii-san, > > On Thu, Mar 12, 2020 at 6:10 AM torii.ken1@xxxxxxxxxxx > <torii.ken1@xxxxxxxxxxx> wrote: > > On Tue, 11 Feb 2020 05:57:35 +0900, > > Greg Kroah-Hartman wrote: > > > On Thu, Jan 30, 2020 at 01:32:50PM +0100, Geert Uytterhoeven > wrote: > > > > On Wed, Jan 29, 2020 at 5:20 PM Eugeniu Rosca > <erosca@xxxxxxxxxxxxxx> wrote: > > > > > From: Torii Kenichi <torii.ken1@xxxxxxxxxxxxxx> > > > > > > > > > > This patch is necessary to use BT module and XM module with > DENSO TEN > > > > > development board. > > > > > > > > > > This patch supports ASYNC_SPD_CUST flag by ioctl(TIOCSSERIAL), > enables > > > > > custom speed setting with setserial(1). > > > > > > > > > > The custom speed is calculated from uartclk and > custom_divisor. > > > > > If custom_divisor is zero, custom speed setting is invalid. > > > > > > > > > > Signed-off-by: Torii Kenichi <torii.ken1@xxxxxxxxxxxxxx> > > > > > [erosca: rebase against v5.5] > > > > > Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx> > > > > > > > > Thanks for your patch! > > > > > > > > While this seems to work fine[*], I have a few > comments/questions: > > > > 1. This feature seems to be deprecated: > > > > > > > > sh-sci e6e68000.serial: setserial sets custom speed > on > > > > ttySC1. This is deprecated. > > > > > > > > 2. As the wanted speed is specified as a divider, the resulting > speed > > > > may be off, cfr. the example for 57600 below. > > > > Note that the SCIF device has multiple clock inputs, and > can do > > > > 57600 perfectly if the right crystal has been fitted. > > > > > > > > 3. What to do with "[PATCH/RFC] serial: sh-sci: Update uartclk > based > > > > on selected clock" > (https://patchwork.kernel.org/patch/11103703/)? > > > > Combined with this, things become pretty complicated and > > > > unpredictable, as uartclk now always reflect the frequency > of the > > > > last used base clock, which was the optimal one for the > previously > > > > used speed.... > > > > > > > > I think it would be easier if we just had an API to specify > a raw speed. > > > > Perhaps that already exists? > > > > > > Yes, see: > > > http://www.panix.com/~grante/arbitrary-baud.c > > > > I saw the code above, I thought I wouldn't write such code normally. > > > > >#include <linux/termios.h> > > > > > >int ioctl(int d, int request, ...); > > > > Do application programmers have to accept this bad code? > > I guess you mean the forward declaration of ioctrl()? > No, they should include <sys/ioctl.h> instead. > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- > geert@xxxxxxxxxxxxxx > > In personal conversations with technical people, I call myself a > hacker. But > when I'm talking to journalists I just say "programmer" or something > like that. > -- Linus Torvalds
