[PATCH] serial: pl01x: Add error value checking

[André Przywara]

On 14/10/2020 09:42, Michal Simek wrote:

Hi,

> There also a need to check return values to make sure that clocks were
> enabled and setup properly.

is that just clean-up or is there a particular problem that's fixed?

I am asking because I am not sure how useful debug output in a console
driver is.
Also in some cases the UART is actually already configured, so failure
to get the clock (due to a sloppy/too complicated DTB) is not really
fatal at the moment.

I am not against this patch, just wanted to make sure we don't break
anything.

Cheers,
Andre


> 
> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
> ---
> 
>  drivers/serial/serial_pl01x.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/serial/serial_pl01x.c b/drivers/serial/serial_pl01x.c
> index 2772c25f1d2d..8672095ea4de 100644
> --- a/drivers/serial/serial_pl01x.c
> +++ b/drivers/serial/serial_pl01x.c
> @@ -362,8 +362,18 @@ int pl01x_serial_ofdata_to_platdata(struct udevice *dev)
>  	plat->clock = dev_read_u32_default(dev, "clock", CONFIG_PL011_CLOCK);
>  	ret = clk_get_by_index(dev, 0, &clk);
>  	if (!ret) {
> -		clk_enable(&clk);
> +		ret = clk_enable(&clk);
> +		if (ret && ret != -ENOSYS) {
> +			dev_err(dev, "failed to enable clock\n");
> +			return ret;
> +		}
> +
>  		plat->clock = clk_get_rate(&clk);
> +		if (IS_ERR_VALUE(plat->clock)) {
> +			dev_err(dev, "failed to get rate\n");
> +			return plat->clock;
> +		}
> +		debug("%s: CLK %d\n", __func__, plat->clock);
>  	}
>  	plat->type = dev_get_driver_data(dev);
>  	plat->skip_init = dev_read_bool(dev, "skip-init");
>