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of serial port driver - add clk_get_rate() support 

Currently this driver expects the clock-frequency attribute. This
patch allows getting clock-frequency through clk driver API
clk_get_rate() if clock-frequency attribute is not defined.

So in the device bindings for serial device, one can add clocks
phandle to refer to the clk device to get the rate.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Murali Karicheri 2012-10-22 11:58:01 -04:00 committed by Greg Kroah-Hartman
parent cadf748690
commit 0bbeb3c3e8
1 changed files with 26 additions and 6 deletions
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30
drivers/tty/serial/of_serial.c
View File

@ -21,8 +21,10 @@
#include <linux/of_serial.h>
#include <linux/of_platform.h>
#include <linux/nwpserial.h>
#include <linux/clk.h>
struct of_serial_info {
struct clk *clk;
int type;
int line;
};
@ -51,7 +53,8 @@ EXPORT_SYMBOL_GPL(tegra_serial_handle_break);
* Fill a struct uart_port for a given device node
*/
static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
int type, struct uart_port *port)
int type, struct uart_port *port,
struct of_serial_info *info)
{
struct resource resource;
struct device_node *np = ofdev->dev.of_node;
@ -60,9 +63,18 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
memset(port, 0, sizeof *port);
if (of_property_read_u32(np, "clock-frequency", &clk)) {
dev_warn(&ofdev->dev, "no clock-frequency property set\n");
/* Get clk rate through clk driver if present */
info->clk = clk_get(&ofdev->dev, NULL);
if (info->clk == NULL) {
dev_warn(&ofdev->dev,
"clk or clock-frequency not defined\n");
return -ENODEV;
}
clk_prepare_enable(info->clk);
clk = clk_get_rate(info->clk);
}
/* If current-speed was set, then try not to change it. */
if (of_property_read_u32(np, "current-speed", &spd) == 0)
port->custom_divisor = clk / (16 * spd);
@ -70,7 +82,7 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
ret = of_address_to_resource(np, 0, &resource);
if (ret) {
dev_warn(&ofdev->dev, "invalid address\n");
return ret;
goto out;
}
spin_lock_init(&port->lock);
@ -97,7 +109,8 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
default:
dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
prop);
return -EINVAL;
ret = -EINVAL;
goto out;
}
}
@ -115,6 +128,10 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
port->handle_break = tegra_serial_handle_break;
return 0;
out:
if (info->clk)
clk_disable_unprepare(info->clk);
return ret;
}
/*
@ -141,7 +158,7 @@ static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
return -ENOMEM;
port_type = (unsigned long)match->data;
ret = of_platform_serial_setup(ofdev, port_type, &port);
ret = of_platform_serial_setup(ofdev, port_type, &port, info);
if (ret)
goto out;
@ -204,6 +221,9 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
/* need to add code for these */
break;
}
if (info->clk)
clk_disable_unprepare(info->clk);
kfree(info);
return 0;
}