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

[Giulio Benetti]

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 at 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 at 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
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>