Messages in this thread | | | From | <> | Subject | RE: [PATCH v1 tty-next 1/2] 8250: microchip: pci1xxxx: Add driver for the quad-uart function in the multi-function endpoint of pci1xxxx device. | Date | Mon, 5 Sep 2022 12:01:12 +0000 |
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> -----Original Message----- > From: Andy Shevchenko <andy.shevchenko@gmail.com> > Sent: Friday, September 2, 2022 8:33 PM > To: Kumaravel Thiagarajan - I21417 <Kumaravel.Thiagarajan@microchip.com> > Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>; Greg Kroah-Hartman > <gregkh@linuxfoundation.org>; Jiri Slaby <jirislaby@kernel.org>; Uwe > Kleine-König <u.kleine-koenig@pengutronix.de>; Johan Hovold > <johan@kernel.org>; Wander Lairson Costa <wander@redhat.com>; Eric > Tremblay <etremblay@distech-controls.com>; Maciej W. Rozycki > <macro@orcam.me.uk>; Geert Uytterhoeven <geert+renesas@glider.be>; > Jeremy Kerr <jk@ozlabs.org>; Phil Edworthy <phil.edworthy@renesas.com>; > Lukas Wunner <lukas@wunner.de>; Linux Kernel Mailing List <linux- > kernel@vger.kernel.org>; open list:SERIAL DRIVERS <linux- > serial@vger.kernel.org>; UNGLinuxDriver > <UNGLinuxDriver@microchip.com> > Subject: Re: [PATCH v1 tty-next 1/2] 8250: microchip: pci1xxxx: Add driver for > the quad-uart function in the multi-function endpoint of pci1xxxx device. > > On Fri, Sep 2, 2022 at 2:57 PM <Kumaravel.Thiagarajan@microchip.com> > wrote: > > > -----Original Message----- > > > From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> > > > Sent: Thursday, September 1, 2022 7:12 PM On Thu, 1 Sep 2022, > > > Kumaravel.Thiagarajan@microchip.com wrote: > > ... > > > > > > > + const unsigned int standard_baud_list[] = {50, 75, > > > > > > + 110, 134, 150, > > > 300, > > > > > > + 600, 1200, 1800, 2000, 2400, 3600, > > > > > > + 4800, 7200, 9600, 19200, 38400, 57600, > > > > > > + 115200, 125000, 136400, 150000, 166700, > > > > > > + 187500, 214300, 250000, 300000, 375000, > > > > > > + 500000, > > > > > > + 750000, 1000000, 1500000}; > > > > > > > > > > Why?! > > > > > > > > The standard baud rates are handled within > > > > serial8250_do_set_termios which is invoked from within > mchp_pci1xxxx_set_termios in first place. > > > > Hence if it matches with any of the standard baudrates, it can > > > > return immediately. > > > > > > Care to explain why the baudrates in your table don't match those in > > > tty_baudrate.c? ...It makes no sense to me that you call these > > > "standard baud rates". > > The baudrates in my table are from our legacy UART IP and these > > baudrates can be generated by the hardware by updating UART_DLL & > > UART_DLM alone as done by the serial8250_do_set_termios. > > I noticed that some of the baud rates in tty_baudrate.c arenot listed > > in this table but will still be handled by the mchp_pci1xxxx_set_termios. > > I can rename standard_baud_list to simply baud_list. Please let me know. > > No, the point is avoid repeating what standard APIs already do. Just make > sure you call it properly and provide _get/_set_divisor() callbacks. Note, your > driver can cope with BOTHER and there all non-standard baud rates go. I will review my driver again and get back to you if required.
Thank You.
Regards, Kumaravel
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