linux-kernel - Re: [PATCH] serial: fsl_lpuart: Remove the alias node dependence

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Message-ID: <20170111072450.GA9980@kroah.com>
Date:   Wed, 11 Jan 2017 08:24:50 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Yuan Yao <yao.yuan@...escale.com>
Cc:     jslaby@...e.com, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org, yao.yuan@....com
Subject: Re: [PATCH] serial: fsl_lpuart: Remove the alias node dependence

On Wed, Dec 14, 2016 at 04:33:32PM +0800, Yuan Yao wrote:
> From: Yuan Yao <yao.yuan@....com>
> 
> Numbering the ttyLPn space should not depend on the generic name
> "serial<n>".
> 
> If don't add the alias node like:"serial0 = &lpuart0;", then lpuart
> will probe failed:
> [    0.773410] fsl-lpuart 2950000.serial: failed to get alias id, errno -19
> 
> So remove the alias node dependence, and add the support for allocate the
> line port automatically.
> 
> Signed-off-by: Yuan Yao <yao.yuan@....com>
> ---
>  drivers/tty/serial/fsl_lpuart.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index a1c6519..c6d639f 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -231,6 +231,8 @@
>  #define DEV_NAME	"ttyLP"
>  #define UART_NR		6
>  
> +static DECLARE_BITMAP(linemap, UART_NR);

Why a bitmap?

> +
>  struct lpuart_port {
>  	struct uart_port	port;
>  	struct clk		*clk;
> @@ -1963,9 +1965,13 @@ static int lpuart_probe(struct platform_device *pdev)
>  
>  	ret = of_alias_get_id(np, "serial");
>  	if (ret < 0) {
> -		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
> -		return ret;
> +		ret = find_first_zero_bit(linemap, UART_NR);
> +		if (ret >= UART_NR) {
> +			dev_err(&pdev->dev, "port line is full, add device failed\n");
> +			return ret;
> +		}

Does this really remove the alias dependancy?

Please use an idr or ida for this instead of a bitmap.

thanks,

greg k-h