Patchwork [1/7] serial: 8250_dw: add support for clk api

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Submitter Maxime Ripard
Date March 19, 2013, 10:35 a.m.
Message ID <1363689316-7847-2-git-send-email-maxime.ripard@free-electrons.com>
Download mbox | patch
Permalink /patch/228997/
State New
Headers show

Comments

Maxime Ripard - March 19, 2013, 10:35 a.m.
From: Emilio López <emilio@elopez.com.ar>

This commit implements support for using the clk api; this lets us use
the "clocks" property with device tree, instead of having to use
clock-frequency.

Signed-off-by: Emilio López <emilio@elopez.com.ar>
---
 drivers/tty/serial/8250/8250_dw.c |   33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)
Maxime Ripard - March 19, 2013, 10:50 a.m.
Hi,

Le 19/03/2013 11:35, Maxime Ripard a écrit :
> From: Emilio López <emilio@elopez.com.ar>
> 
> This commit implements support for using the clk api; this lets us use
> the "clocks" property with device tree, instead of having to use
> clock-frequency.
> 
> Signed-off-by: Emilio López <emilio@elopez.com.ar>
> ---
>  drivers/tty/serial/8250/8250_dw.c |   33 ++++++++++++++++++++++++---------
>  1 file changed, 24 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> index db0e66f..3dedd24 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -26,6 +26,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
>  #include <linux/acpi.h>
> +#include <linux/clk.h>
>  
>  #include "8250.h"
>  
> @@ -55,8 +56,9 @@
>  
>  
>  struct dw8250_data {
> -	int	last_lcr;
> -	int	line;
> +	int		last_lcr;
> +	int		line;
> +	struct clk	*clk;
>  };
>  
>  static void dw8250_serial_out(struct uart_port *p, int offset, int value)
> @@ -136,8 +138,13 @@ static int dw8250_probe_of(struct uart_port *p)
>  	if (!of_property_read_u32(np, "reg-shift", &val))
>  		p->regshift = val;
>  
> +	/* clock got configured through clk api, all done */
> +	if (IS_ERR(p->uartclk))

Hmm, I messed up here.

I'll resend a new version of this mail without this IS_ERR call

Maxime

Patch

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index db0e66f..3dedd24 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -26,6 +26,7 @@ 
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
+#include <linux/clk.h>
 
 #include "8250.h"
 
@@ -55,8 +56,9 @@ 
 
 
 struct dw8250_data {
-	int	last_lcr;
-	int	line;
+	int		last_lcr;
+	int		line;
+	struct clk	*clk;
 };
 
 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
@@ -136,8 +138,13 @@  static int dw8250_probe_of(struct uart_port *p)
 	if (!of_property_read_u32(np, "reg-shift", &val))
 		p->regshift = val;
 
+	/* clock got configured through clk api, all done */
+	if (IS_ERR(p->uartclk))
+		return 0;
+
+	/* try to find out clock frequency from DT as fallback */
 	if (of_property_read_u32(np, "clock-frequency", &val)) {
-		dev_err(p->dev, "no clock-frequency property set\n");
+		dev_err(p->dev, "clk or clock-frequency not defined\n");
 		return -EINVAL;
 	}
 	p->uartclk = val;
@@ -294,9 +301,20 @@  static int dw8250_probe(struct platform_device *pdev)
 	if (!uart.port.membase)
 		return -ENOMEM;
 
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->clk = devm_clk_get(&pdev->dev, NULL);
+	if (!IS_ERR(data->clk)) {
+		clk_prepare_enable(data->clk);
+		uart.port.uartclk = clk_get_rate(data->clk);
+	}
+
 	uart.port.iotype = UPIO_MEM;
 	uart.port.serial_in = dw8250_serial_in;
 	uart.port.serial_out = dw8250_serial_out;
+	uart.port.private_data = data;
 
 	dw8250_setup_port(&uart);
 
@@ -312,12 +330,6 @@  static int dw8250_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
-	if (!data)
-		return -ENOMEM;
-
-	uart.port.private_data = data;
-
 	data->line = serial8250_register_8250_port(&uart);
 	if (data->line < 0)
 		return data->line;
@@ -333,6 +345,9 @@  static int dw8250_remove(struct platform_device *pdev)
 
 	serial8250_unregister_port(data->line);
 
+	if (!IS_ERR(data->clk))
+		clk_disable_unprepare(data->clk);
+
 	return 0;
 }