On Sat, Oct 21, 2023 at 07:02:40PM +0200, Greg KH wrote: > Note, your subject line needs to change. > > On Fri, Oct 20, 2023 at 12:00:27PM -0400, Frank Li wrote: > > In typical embedded Linux systems, UART consoles require at least two pins, > > TX and RX. In scenarios where I2C/I3C devices like sensors or PMICs are > > present, we can save these two pins by using this driver. Pins is crucial > > "Pins are crucial" > > > resources, especially in small chip packages. > > > > This introduces support for using the I3C bus to transfer console tty data, > > effectively replacing the need for dedicated UART pins. This not only > > conserves valuable pin resources but also facilitates testing of I3C's > > advanced features, including early termination, in-band interrupt (IBI) > > support, and the creation of more complex data patterns. Additionally, > > it aids in identifying and addressing issues within the I3C controller > > driver. > > But where is the serial data ending up at? Not a normal uart, what is > on the other end? And do line settings mean anything here? Currently, it use slave i3c code. https://lore.kernel.org/imx/20231018215809.3477437-1-Frank.Li@xxxxxxx/T/#t idealy build an i3c->usb dongle to bride it to usb acm. > > > > > Signed-off-by: Frank Li <Frank.Li@xxxxxxx> > > --- > > > > Notes: > > This patch depend on > > https://lore.kernel.org/imx/20231018205929.3435110-1-Frank.Li@xxxxxxx/T/#t > > Let's wait for those to be accepted first, right? Yes. > > > +static DEFINE_IDR(i3c_tty_minors); > > +static DEFINE_MUTEX(i3c_tty_minors_lock); > > I thought idr didn't need a mutex anymore, are you sure this is still > needed? > > > +static struct tty_driver *i3c_tty_driver; > > + > > +#define I3C_TTY_MINORS 256 > > Do you really need 256 minors? Any resource concern about it. Maybe 32/64 is enough. I refer from USB tty driver. > > > +#define I3C_TTY_TRANS_SIZE 16 > > +#define I3C_TTY_RX_STOP 0 > > +#define I3C_TTY_RETRY 20 > > +#define I3C_TTY_YIELD_US 100 > > + > > +struct ttyi3c_port { > > + struct tty_port port; > > + int minor; > > + spinlock_t xlock; /* protect xmit */ > > + char tx_buff[I3C_TTY_TRANS_SIZE]; > > + char rx_buff[I3C_TTY_TRANS_SIZE]; > > + struct i3c_device *i3cdev; > > + struct work_struct txwork; > > + struct work_struct rxwork; > > + struct completion txcomplete; > > + unsigned long status; > > + int buf_overrun; > > You set buf_overrun but never do anything with it. Why care about it? > > Other than these minor things, looks sane, nice work. > > thanks, > > greg k-h
