[PATCH 14/20] serial_lpuart: add clock enable if CONFIG_CLK is defined

Giulio Benetti
2019-12-09T15:20:10Z

Hi Lukasz,

On 12/8/19 3:52 PM, Lukasz Majewski wrote:
> On Wed, 4 Dec 2019 18:44:33 +0100
> Giulio Benetti <giulio.benetti@benettiengineering.com> wrote:
>
>> This driver assumes that lpuart clock is already enabled before
>> probing but using DM only lpuart won't be automatically enabled so add
>> clk_enable() when probing if CONFIG_CLK is defined.
>>
>> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
>> ---
>> drivers/serial/serial_lpuart.c | 13 +++++++++++++
>> 1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/serial/serial_lpuart.c
>> b/drivers/serial/serial_lpuart.c index 4b0a964d1b..52bd2baf7d 100644
>> --- a/drivers/serial/serial_lpuart.c
>> +++ b/drivers/serial/serial_lpuart.c
>> @@ -483,6 +483,19 @@ static int lpuart_serial_pending(struct udevice
>> *dev, bool input)
>> static int lpuart_serial_probe(struct udevice *dev)
>> {
>> +#if CONFIG_IS_ENABLED(CLK)
>> + struct clk per_clk;
>> + int ret;
>> +
>> + ret = clk_get_by_name(dev, "per", &per_clk);
>> + if (ret) {
>> + dev_err(dev, "Failed to get per clk: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + clk_enable(&per_clk);
>> +#endif
>> +
>
> I think that this change will _silently_ break all boards which do have
> CONFIG_CLK enabled (for some clocks/drivers), but did not yet provided
> CCF definition for lpuart clock.

Oops, yes, you're totally right.
Would it be correct if I try to retrieve clock and otherwise I fallback
sending warnings like following?:

`
static int lpuart_serial_probe(struct udevice *dev)
{
#if CONFIG_IS_ENABLED(CLK)
struct clk per_clk;
int ret;

ret = clk_get_by_name(dev, "per", &per_clk);
if (!ret) {
ret = clk_enable(&per_clk);
if (ret) {
dev_err(dev, "Failed to get per clk: %d\n",
ret);
return;
}
} else {
dev_warn(dev, "Failed to get per clk: %d\n",
ret);
}
#endif

....

`

Best regards
--
Giulio Benetti
Benetti Engineering sas

>
> Was this series checked with travis-ci?
>
> For example:
> https://travis-ci.org/lmajewski/u-boot-dfu/jobs/622226547
>
>> if (is_lpuart32(dev))
>> return _lpuart32_serial_init(dev);
>> else
>
>
>
>
> Best regards,
>
> Lukasz Majewski
>
> --
>
> DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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>