Re: [V5] tty: serial: qcom-geni-serial: Fix get_clk_div_rate() which otherwise could return a sub-optimal clock rate.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 12. 07. 22, 14:45, Vijaya Krishna Nivarthi wrote:
...
+static unsigned long get_clk_div_rate(struct clk *clk, struct device *dev,
+		unsigned int baud, unsigned int sampling_rate, unsigned int *clk_div)
+{
+	unsigned long ser_clk;
+	unsigned long desired_clk;
+
+	desired_clk = baud * sampling_rate;
+	if (!desired_clk) {
+		dev_dbg(dev, "Invalid frequency\n");
+		return 0;
  	}
- *clk_div = ser_clk / desired_clk;
-	if (!(*clk_div))
-		*clk_div = 1;
+	/*
+	 * try to find a clock rate within 2% tolerance, then within

"then within" ... "5" is missing, perhaps?

+	 */
+	ser_clk = find_clk_rate_in_tol(clk, desired_clk, clk_div, 2);
+	if (!ser_clk)
+		ser_clk = find_clk_rate_in_tol(clk, desired_clk, clk_div, 5);
+
+	if (!ser_clk)
+		dev_err(dev, "Couldn't find suitable clock rate for %lu\n", desired_clk);
+	else
+		dev_dbg(dev, "desired_clk-%lu, ser_clk-%lu, clk_div-%u\n",
+				desired_clk, ser_clk, *clk_div);
return ser_clk;
  }
@@ -1021,8 +1040,8 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
  	if (ver >= QUP_SE_VERSION_2_5)
  		sampling_rate /= 2;
- clk_rate = get_clk_div_rate(port->se.clk, baud,
-		sampling_rate, &clk_div);
+	clk_rate = get_clk_div_rate(port->se.clk, port->se.dev, baud,

Maybe worth passing whole geni_se (port->se) then?

+					sampling_rate, &clk_div);
  	if (!clk_rate)
  		goto out_restart_rx;

thanks,
--
js
suse labs



[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux PPP]     [Linux FS]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linmodem]     [Device Mapper]     [Linux Kernel for ARM]

  Powered by Linux