Thread (46 messages) 46 messages, 14 authors, 2014-12-03

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

From: orsonzhai@gmail.com (Orson Zhai)
Date: 2014-11-28 11:40:42
Also in: linux-api, linux-devicetree, linux-serial, lkml

Hi, Alan,

Thanks for your comments!
Some question for them below,

On 2014?11?26? 20:33, One Thousand Gnomes wrote:
quoted
+		 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?
quoted
+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?
quoted
+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
quoted
+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.
quoted
+
+	/* 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);

quoted
+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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