Re: [PATCH 2/2] Input: pm8941-powerkey - fix debounce on gen2+ PMICs

[Caleb Connolly <caleb.connolly@linaro.org>]

On 30/05/2023 10:36, Konrad Dybcio wrote:
> 
> 
> On 29.05.2023 21:55, Caleb Connolly wrote:
>> Since PM8998/PM660, the power key debounce register was redefined to
>> support shorter debounce times. On PM8941 the shortest debounce time
>> (represented by register value 0) was 15625us, on PM8998 the shortest
>> debounce time is 62us, with the default being 2ms.
>>
>> Adjust the bit shift to correctly program debounce on PM8998 and newer.
>>
>> Fixes: 68c581d5e7d8 ("Input: add Qualcomm PM8941 power key driver")
>> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
>> ---
>> This patch shouldn't be backported earlier then 5.4, as that is the
>> first kernel with support for PM8998.
>> ---
>>  drivers/input/misc/pm8941-pwrkey.c | 19 +++++++++++++++----
>>  1 file changed, 15 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/input/misc/pm8941-pwrkey.c b/drivers/input/misc/pm8941-pwrkey.c
>> index b6a27ebae977..74d77d8aaeff 100644
>> --- a/drivers/input/misc/pm8941-pwrkey.c
>> +++ b/drivers/input/misc/pm8941-pwrkey.c
>> @@ -50,7 +50,10 @@
>>  #define  PON_RESIN_PULL_UP		BIT(0)
>>  
>>  #define PON_DBC_CTL			0x71
>> -#define  PON_DBC_DELAY_MASK		0x7
>> +#define  PON_DBC_DELAY_MASK_GEN1	0x7
>> +#define  PON_DBC_DELAY_MASK_GEN2	0xf
>> +#define  PON_DBC_SHIFT_GEN1		6
>> +#define  PON_DBC_SHIFT_GEN2		14
> mask+shift -> field_prep/get?

I figured it was better to keep it consistent and try to minimise the
diff so that backporting is easier.

Migrating over to bitfield helpers probably makes sense to do as a
separate change - maybe if a new platform comes along and requires even
more additional complexity?
> 
> Nice find!
> 
> Konrad
>>  
>>  struct pm8941_data {
>>  	unsigned int	pull_up_bit;
>> @@ -247,7 +250,7 @@ static int pm8941_pwrkey_probe(struct platform_device *pdev)
>>  	struct device *parent;
>>  	struct device_node *regmap_node;
>>  	const __be32 *addr;
>> -	u32 req_delay;
>> +	u32 req_delay, mask, delay_shift;
>>  	int error;
>>  
>>  	if (of_property_read_u32(pdev->dev.of_node, "debounce", &req_delay))
>> @@ -336,12 +339,20 @@ static int pm8941_pwrkey_probe(struct platform_device *pdev)
>>  	pwrkey->input->phys = pwrkey->data->phys;
>>  
>>  	if (pwrkey->data->supports_debounce_config) {
>> -		req_delay = (req_delay << 6) / USEC_PER_SEC;
>> +		if (pwrkey->subtype >= PON_SUBTYPE_GEN2_PRIMARY) {
>> +			mask = PON_DBC_DELAY_MASK_GEN2;
>> +			delay_shift = PON_DBC_SHIFT_GEN2;
>> +		} else {
>> +			mask = PON_DBC_DELAY_MASK_GEN1;
>> +			delay_shift = PON_DBC_SHIFT_GEN1;
>> +		}
>> +
>> +		req_delay = (req_delay << delay_shift) / USEC_PER_SEC;
>>  		req_delay = ilog2(req_delay);
>>  
>>  		error = regmap_update_bits(pwrkey->regmap,
>>  					   pwrkey->baseaddr + PON_DBC_CTL,
>> -					   PON_DBC_DELAY_MASK,
>> +					   mask,
>>  					   req_delay);
>>  		if (error) {
>>  			dev_err(&pdev->dev, "failed to set debounce: %d\n",
>>

-- 
// Caleb (they/them)