[PATCH] seria: sirf: only use lookup table to set baudrate when ioclk=150MHz

Barry Song Barry.Song at csr.com
Tue Dec 25 05:26:02 EST 2012


From: Barry Song <Baohua.Song at csr.com>

The fast lookup table to set baudrate is only right when ioclk
is 150MHz. for most platforms, ioclk is 150MHz, but some boards
might set ioclk to other frequency.

so re-calc the clk_div_reg when ioclk is not 150MHz.

Signed-off-by: Barry Song <Baohua.Song at csr.com>
---
 drivers/tty/serial/sirfsoc_uart.c |   18 +++++++++++++-----
 1 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index 142217c..fe28b1f 100644
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c
@@ -375,7 +375,12 @@ static void sirfsoc_uart_set_termios(struct uart_port *port,
 	int		threshold_div;
 	int		temp;
 
-	ioclk_rate = 150000000;
+	struct clk *clk = clk_get_sys("io", NULL);
+	BUG_ON(IS_ERR(clk));
+
+	ioclk_rate = clk_get_rate(clk);
+	clk_put(clk);
+
 	switch (termios->c_cflag & CSIZE) {
 	default:
 	case CS8:
@@ -431,10 +436,13 @@ static void sirfsoc_uart_set_termios(struct uart_port *port,
 			sirfsoc_uart_disable_ms(port);
 	}
 
-	/* common rate: fast calculation */
-	for (ic = 0; ic < SIRF_BAUD_RATE_SUPPORT_NR; ic++)
-		if (baud_rate == baudrate_to_regv[ic].baud_rate)
-			clk_div_reg = baudrate_to_regv[ic].reg_val;
+	if (ioclk_rate == 150000000) {
+		/* common rate: fast calculation */
+		for (ic = 0; ic < SIRF_BAUD_RATE_SUPPORT_NR; ic++)
+			if (baud_rate == baudrate_to_regv[ic].baud_rate)
+				clk_div_reg = baudrate_to_regv[ic].reg_val;
+	}
+
 	setted_baud = baud_rate;
 	/* arbitary rate setting */
 	if (unlikely(clk_div_reg == 0))
-- 
1.7.5.4



Member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom
More information can be found at www.csr.com. Follow CSR on Twitter at http://twitter.com/CSR_PLC and read our blog at www.csr.com/blog



More information about the linux-arm-kernel mailing list