Thread (10 messages) flat view 10 messages, 3 authors, 2013-03-15

[PATCH 1/6] serial: 8250_dw: add support for clocks property when using DeviceTree

From: heikki.krogerus@linux.intel.com (Heikki Krogerus)
Date: 2013-03-15 12:56:23
Also in: linux-serial, lkml

Hi,

On Thu, Mar 07, 2013 at 11:14:15PM +0100, Maxime Ripard wrote:
From: Emilio L?pez <emilio@elopez.com.ar>

This commit implements support for using the "clocks" DT property, instead
of having to use clock-frequency.

Signed-off-by: Emilio L?pez <emilio@elopez.com.ar>
---
 drivers/tty/serial/8250/8250_dw.c |   32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)
<snip>
quoted hunk ↗ jump to hunk
@@ -137,8 +140,15 @@ static int dw8250_probe_of(struct uart_port *p)
 		p->regshift = val;
 
 	if (of_property_read_u32(np, "clock-frequency", &val)) {
-		dev_err(p->dev, "no clock-frequency property set\n");
-		return -EINVAL;
+		/* Get clk rate through clk driver if present */
+		data->clk = clk_get(p->dev, NULL);
+		if (IS_ERR(data->clk)) {
+			dev_err(p->dev, "clk or clock-frequency not defined\n");
+			return -EINVAL;
+		}
+
+		clk_prepare_enable(data->clk);
+		val = clk_get_rate(data->clk);
Don't get the clk here..
quoted hunk ↗ jump to hunk
 	}
 	p->uartclk = val;
 
@@ -300,6 +310,12 @@ static int dw8250_probe(struct platform_device *pdev)
Get it here so it is then handled for also others besides DT users.
And prefer devm_clk_get(). Something like this:

        ...
        uart.port.membase = ioremap(regs->start, resource_size(regs));
        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);
+       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);
        ... 

Then in dw8250_probe_of() you need to use the "clock-frequency"
property only when p->uartclk is 0.

Thanks,

-- 
heikki
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