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? > > 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? > +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? > +#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
