[PATCH v2] serial: sirf: only use lookup table to set baudrate when ioclk=150MHz
From: Barry Song <hidden>
Date: 2013-01-16 06:49:27
Also in:
linux-serial
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
From: Barry Song <redacted> 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. this patch also gets clk in probe and puts it in remove. Signed-off-by: Barry Song <redacted> Cc: Russell King <redacted> --- -v2: 1. Get the clock at probe or port initialization time. Save that pointer according to Russell King's feedback; 2. rebase to tty/tty-next as this one has been applied: serial: sirf: add support for new SiRFmarco SMP SoC http://git.kernel.org/?p=linux/kernel/git/gregkh/tty.git;h=5425e0 drivers/tty/serial/sirfsoc_uart.c | 28 +++++++++++++++++++++------- drivers/tty/serial/sirfsoc_uart.h | 1 + 2 files changed, 22 insertions(+), 7 deletions(-)
diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index 8f3d6c0..6bbfe99 100644
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c@@ -357,7 +357,6 @@ static void sirfsoc_uart_set_termios(struct uart_port *port, struct ktermios *old) { struct sirfsoc_uart_port *sirfport = to_sirfport(port); - unsigned long ioclk_rate; unsigned long config_reg = 0; unsigned long baud_rate; unsigned long setted_baud;
@@ -369,7 +368,6 @@ static void sirfsoc_uart_set_termios(struct uart_port *port, int threshold_div; int temp; - ioclk_rate = 150000000; switch (termios->c_cflag & CSIZE) { default: case CS8:
@@ -425,14 +423,17 @@ 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 (port->uartclk == 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)) - clk_div_reg = sirfsoc_calc_sample_div(baud_rate, ioclk_rate, + clk_div_reg = sirfsoc_calc_sample_div(baud_rate, port->uartclk, &setted_baud); wr_regl(port, SIRFUART_DIVISOR, clk_div_reg);
@@ -691,6 +692,14 @@ int sirfsoc_uart_probe(struct platform_device *pdev) goto err; } + sirfport->clk = clk_get(&pdev->dev, NULL); + if (IS_ERR(sirfport->clk)) { + ret = PTR_ERR(sirfport->clk); + goto clk_err; + } + clk_prepare_enable(sirfport->clk); + port->uartclk = clk_get_rate(sirfport->clk); + port->ops = &sirfsoc_uart_ops; spin_lock_init(&port->lock);
@@ -704,6 +713,9 @@ int sirfsoc_uart_probe(struct platform_device *pdev) return 0; port_err: + clk_disable_unprepare(sirfport->clk); + clk_put(sirfport->clk); +clk_err: platform_set_drvdata(pdev, NULL); if (sirfport->hw_flow_ctrl) pinctrl_put(sirfport->p);
@@ -718,6 +730,8 @@ static int sirfsoc_uart_remove(struct platform_device *pdev) platform_set_drvdata(pdev, NULL); if (sirfport->hw_flow_ctrl) pinctrl_put(sirfport->p); + clk_disable_unprepare(sirfport->clk); + clk_put(sirfport->clk); uart_remove_one_port(&sirfsoc_uart_drv, port); return 0; }
diff --git a/drivers/tty/serial/sirfsoc_uart.h b/drivers/tty/serial/sirfsoc_uart.h
index 6431640..85328ba 100644
--- a/drivers/tty/serial/sirfsoc_uart.h
+++ b/drivers/tty/serial/sirfsoc_uart.h@@ -163,6 +163,7 @@ struct sirfsoc_uart_port { struct uart_port port; struct pinctrl *p; + struct clk *clk; }; /* Hardware Flow Control */
--
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