Re: [PATCH] serial/imx: propagate error from of_alias_get_id insteadof using -ENODEV

From: Uwe Kleine-König
Date: Wed Dec 14 2011 - 15:31:57 EST


Hello,

On Wed, Dec 14, 2011 at 09:26:51PM +0100, Uwe Kleine-König wrote:
> A quick look at of_alias_get_id shows that in the error case it returns
> -ENODEV, too, but still it's better style to propagate the value as is.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
> Cc: Alan Cox <alan@xxxxxxxxxxxxxxx>
> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
> Cc: Jeremy Kerr <jeremy.kerr@xxxxxxxxxxxxx>
> Cc: Jason Liu <jason.hui@xxxxxxxxxx>
> Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> ---
> drivers/tty/serial/imx.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 163fc90..75c159a 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -1301,7 +1301,7 @@ static int serial_imx_probe_dt(struct imx_port *sport,
> ret = of_alias_get_id(np, "serial");
> if (ret < 0) {
> dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
> - return -ENODEV;
> + return ret;
> }
> sport->port.line = ret;
>
One more comment on serial_imx_probe_dt:

It is used as follows:

ret = serial_imx_probe_dt(sport, pdev);
if (ret == -ENODEV)
serial_imx_probe_pdata(sport, pdev);

IMHO you should distinguish here more carefully between the different
-ENODEV cases. It's OK to call serial_imx_probe_pdata() if

!pdev->dev.of_node

but if

of_alias_get_id(np, "serial")

returns an error isn't that something that should make the probing of
the device fail instead of relying on platform data and the device id
that are non-existant and more or less random respectively if the device
is instantiated by dt?

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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