linux-kernel - Re: [PATCH 1/6] serial: 8250_dw: add support for clk api

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Date:	Fri, 15 Mar 2013 22:39:17 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:	linux-arm-kernel@...ts.infradead.org,
	Emilio López <emilio@...pez.com.ar>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
	sunny@...winnertech.com, shuge@...winnertech.com,
	Jiri Slaby <jslaby@...e.cz>, kevin@...winnertech.com
Subject: Re: [PATCH 1/6] serial: 8250_dw: add support for clk api

On Fri, Mar 15, 2013 at 09:06:23PM +0100, Maxime Ripard wrote:
> +	/* clock got configured through clk api, all done */
> +	if (p->uartclk)

	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 +301,21 @@ 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);

	if (!IS_ERR(data->clk))
		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);

What if data->clk is invalid?

	if (!IS_ERR(data->clk)
		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);
>  

	if (!IS_ERR(data->clk)

> +	clk_disable_unprepare(data->clk);
> +
>  	return 0;
>  }
>  
> -- 
> 1.7.10.4
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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