Re: [PATCH v3 5/5] tty/serial: Add Spreadtrum sc9836-uart driver support

[Orson Zhai]

Hi, Alan,

Thanks for your comments!
Some question for them below,

On 2014å11æ26æ 20:33, One Thousand Gnomes wrote:
> > +		 213 = /dev/ttySPX0		SPRD serial port 0
> > +		    ...
> > +		 216 = /dev/ttySPX3		SPRD serial port 3
> Please use dynamic allocation or give a very very good reason why you
> can't
do we just leave the .major & .minor as NULL in struct uart_driver for 
dynamic allocation?
> > +config SERIAL_SPRD_NR
> > +        int "Maximum number of sprd serial ports"
> > +        depends on SERIAL_SPRD
> > +        default "4"
> If you are doing dynamic allocation this should pretty much go away
I think you mean getting the number of uarts from dt and dynamically 
allocate their port structure?
> > +static int sprd_startup(struct uart_port *port)
> > +{
> > +	int ret = 0;
> > +	unsigned int ien, ctrl1;
> > +	struct sprd_uart_port *sp;
> > +
> > +	serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) | THLD_RX_FULL));
> > +
> > +	/* clear rx fifo */
> > +	while (serial_in(port, SPRD_STS1) & 0x00ff)
> > +		serial_in(port, SPRD_RXD);
> > +
> > +	/* clear tx fifo */
> > +	while (serial_in(port, SPRD_STS1) & 0xff00)
> > +		;
> Missing a cpu_relax and I would have thought a timeout on both of these.
We will add in V4
> > +static void sprd_set_termios(struct uart_port *port,
> > +				    struct ktermios *termios,
> > +				    struct ktermios *old)
> > +{
> > +	unsigned int baud, quot;
> > +	/* calculate parity */
> > +	lcr &= ~SPRD_LCR_PARITY;
> > +	if (termios->c_cflag & PARENB) {
> > +		lcr |= SPRD_LCR_PARITY_EN;
> > +		if (termios->c_cflag & PARODD)
> > +			lcr |= SPRD_LCR_ODD_PAR;
> > +		else
> > +			lcr |= SPRD_LCR_EVEN_PAR;
> > +	}
> If you don't support mark/space parity then also clear CMSPAR in
> termios->c_cflag.
just simply use code like "termios->c_cflag &= ~CMSPAR" ?

> If you do then it ought to be handled above.
>
> > +
> > +	/* clock divider bit16~bit20 */
> > +	serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16);
> > +	serial_out(port, SPRD_LCR, lcr);
> > +	fc |= 0x3e00 | THLD_RX_FULL;
> > +	serial_out(port, SPRD_CTL1, fc);
> Also set the resulting baud back into the termios (see the 8250 termios
> for an example)
you mean something like this part ?

/* Don't rewrite B0 */
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);


> > +static int __init sprd_console_setup(struct console *co, char *options)
> > +{
> > +	struct uart_port *port;
> > +	int baud = 115200;
> > +	int bits = 8;
> > +	int parity = 'n';
> > +	int flow = 'n';
> > +
> > +	if (unlikely(co->index >= UART_NR_MAX || co->index < 0))
> > +		co->index = 0;
> > +
> > +	port = (struct uart_port *)sprd_port[co->index];
> > +	if (port == NULL) {
> > +		pr_info("srial port %d not yet initialized\n", co->index);
> Typo
it will be fixed :)

Thanks,
Orson
> Looks basically sound to me
>
> Alan

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