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SubjectRE: [PATCH] serial: fsl_lpuart: Remove the alias node dependence
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On Wed, Jan 11, 2016 at 04:33:32PM +0800, Greg KH wrote:
> On Wed, Dec 14, 2016 at 04:33:32PM +0800, Yuan Yao wrote:
> > From: Yuan Yao <yao.yuan@nxp.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@nxp.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?

Because I think the bitmap is enough to meet the need.
Are there any shortcomings for bitmap used here?

>
> > +
> > 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.
>

Hi Greg,

Thanks for your review.

Is there any advantage for use an idr or ida instead of bitmap?
I will hope to get your guidance.

Thanks.

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