[PATCH 1/6] serial: 8250_dw: add support for clk api

Maxime Ripard
2013-03-15T20:06:23Z

From: Emilio L?pez <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 L?pez <emilio@elopez.com.ar>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
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..9a834a1 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 (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 +301,21 @@ 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))
+ data->clk = NULL;
+ else
+ clk_prepare_enable(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;
+ uart.port.uartclk = clk_get_rate(data->clk);

dw8250_setup_port(&uart);

@@ -312,12 +331,6 @@ 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 +346,8 @@ static int dw8250_remove(struct platform_device *pdev)

serial8250_unregister_port(data->line);

+ clk_disable_unprepare(data->clk);
+
return 0;
}

--
1.7.10.4