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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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32
drivers/tty/serial/of_serial.c
View File

@ -21,8 +21,10 @@
#include <linux/of_serial.h> #include <linux/of_serial.h>
#include <linux/of_platform.h> #include <linux/of_platform.h>
#include <linux/nwpserial.h> #include <linux/nwpserial.h>
#include <linux/clk.h>
struct of_serial_info { struct of_serial_info {
struct clk *clk;
int type; int type;
int line; int line;
}; };
@ -51,7 +53,8 @@ EXPORT_SYMBOL_GPL(tegra_serial_handle_break);
* Fill a struct uart_port for a given device node * Fill a struct uart_port for a given device node
*/ */
static int __devinit of_platform_serial_setup(struct platform_device *ofdev, 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 resource resource;
struct device_node *np = ofdev->dev.of_node; struct device_node *np = ofdev->dev.of_node;
@ -60,8 +63,17 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
memset(port, 0, sizeof *port); memset(port, 0, sizeof *port);
if (of_property_read_u32(np, "clock-frequency", &clk)) { if (of_property_read_u32(np, "clock-frequency", &clk)) {
dev_warn(&ofdev->dev, "no clock-frequency property set\n");
return -ENODEV; /* 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 current-speed was set, then try not to change it. */
if (of_property_read_u32(np, "current-speed", &spd) == 0) if (of_property_read_u32(np, "current-speed", &spd) == 0)
@ -70,7 +82,7 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
ret = of_address_to_resource(np, 0, &resource); ret = of_address_to_resource(np, 0, &resource);
if (ret) { if (ret) {
dev_warn(&ofdev->dev, "invalid address\n"); dev_warn(&ofdev->dev, "invalid address\n");
return ret; goto out;
} }
spin_lock_init(&port->lock); spin_lock_init(&port->lock);
@ -97,7 +109,8 @@ static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
default: default:
dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n", dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
prop); 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; port->handle_break = tegra_serial_handle_break;
return 0; 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; return -ENOMEM;
port_type = (unsigned long)match->data; 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) if (ret)
goto out; goto out;
@ -204,6 +221,9 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
/* need to add code for these */ /* need to add code for these */
break; break;
} }
if (info->clk)
clk_disable_unprepare(info->clk);
kfree(info); kfree(info);
return 0; return 0;
} }