[v2] pinctrl: single: support GPIO for bits pinctrl
diff mbox

Message ID 1436191025-9024-1-git-send-email-jun.nie@linaro.org
State New
Headers show

Commit Message

Jun Nie July 6, 2015, 1:57 p.m. UTC
Support GPIO for one register control multiple pins case
with calculating register offset first, then bit offset.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
---
 drivers/pinctrl/pinctrl-single.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

Comments

Tony Lindgren July 6, 2015, 3:42 p.m. UTC | #1
* Jun Nie <jun.nie@linaro.org> [150706 06:59]:
> Support GPIO for one register control multiple pins case
> with calculating register offset first, then bit offset.
> 
> Signed-off-by: Jun Nie <jun.nie@linaro.org>
> ---
>  drivers/pinctrl/pinctrl-single.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
> index 13b45f2..4f23ef0 100644
> --- a/drivers/pinctrl/pinctrl-single.c
> +++ b/drivers/pinctrl/pinctrl-single.c
> @@ -494,7 +494,7 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
>  	struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
>  	struct pcs_gpiofunc_range *frange = NULL;
>  	struct list_head *pos, *tmp;
> -	int mux_bytes = 0;
> +	int offset, mux_bytes = 0;
>  	unsigned data;
>  
>  	/* If function mask is null, return directly. */
> @@ -507,9 +507,23 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
>  			|| pin < frange->offset)
>  			continue;
>  		mux_bytes = pcs->width / BITS_PER_BYTE;
> -		data = pcs->read(pcs->base + pin * mux_bytes) & ~pcs->fmask;
> -		data |= frange->gpiofunc;
> -		pcs->write(data, pcs->base + pin * mux_bytes);
> +		if (pcs->bits_per_mux) {
> +			int pin_pos, byte_num, num_pins_in_register;
> +
> +			num_pins_in_register = pcs->width / pcs->bits_per_pin;
> +			byte_num = (pcs->bits_per_pin * pin) / BITS_PER_BYTE;
> +			offset = (byte_num / mux_bytes) * mux_bytes;
> +			pin_pos = pin % num_pins_in_register;
> +			pin_pos *= pcs->bits_per_pin;
> +			data = pcs->read(pcs->base + offset) &
> +				~(pcs->fmask << pin_pos);
> +			data |= (frange->gpiofunc & pcs->fmask) << pin_pos;

I don't quite follow you here.. The pcs->fmask is for the whole register,
so I think the fmask should be checked the same way in this case also:
		
			data = pcs->read(pcs->base + offset) & ~pcs->fmask;
			...

I don't think we can safely assume the fmask would behave differently
in this case.

Regards,

Tony
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Jun Nie July 7, 2015, 1:57 a.m. UTC | #2
2015-07-06 23:42 GMT+08:00 Tony Lindgren <tony@atomide.com>:
> * Jun Nie <jun.nie@linaro.org> [150706 06:59]:
>> Support GPIO for one register control multiple pins case
>> with calculating register offset first, then bit offset.
>>
>> Signed-off-by: Jun Nie <jun.nie@linaro.org>
>> ---
>>  drivers/pinctrl/pinctrl-single.c | 22 ++++++++++++++++++----
>>  1 file changed, 18 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
>> index 13b45f2..4f23ef0 100644
>> --- a/drivers/pinctrl/pinctrl-single.c
>> +++ b/drivers/pinctrl/pinctrl-single.c
>> @@ -494,7 +494,7 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
>>       struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
>>       struct pcs_gpiofunc_range *frange = NULL;
>>       struct list_head *pos, *tmp;
>> -     int mux_bytes = 0;
>> +     int offset, mux_bytes = 0;
>>       unsigned data;
>>
>>       /* If function mask is null, return directly. */
>> @@ -507,9 +507,23 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
>>                       || pin < frange->offset)
>>                       continue;
>>               mux_bytes = pcs->width / BITS_PER_BYTE;
>> -             data = pcs->read(pcs->base + pin * mux_bytes) & ~pcs->fmask;
>> -             data |= frange->gpiofunc;
>> -             pcs->write(data, pcs->base + pin * mux_bytes);
>> +             if (pcs->bits_per_mux) {
>> +                     int pin_pos, byte_num, num_pins_in_register;
>> +
>> +                     num_pins_in_register = pcs->width / pcs->bits_per_pin;
>> +                     byte_num = (pcs->bits_per_pin * pin) / BITS_PER_BYTE;
>> +                     offset = (byte_num / mux_bytes) * mux_bytes;
>> +                     pin_pos = pin % num_pins_in_register;
>> +                     pin_pos *= pcs->bits_per_pin;
>> +                     data = pcs->read(pcs->base + offset) &
>> +                             ~(pcs->fmask << pin_pos);
>> +                     data |= (frange->gpiofunc & pcs->fmask) << pin_pos;
>
> I don't quite follow you here.. The pcs->fmask is for the whole register,
> so I think the fmask should be checked the same way in this case also:
>
>                         data = pcs->read(pcs->base + offset) & ~pcs->fmask;
>                         ...
>
> I don't think we can safely assume the fmask would behave differently
> in this case.

My understanding to bits_per_mux flags here is that one 32bits
register shall control 16 pins if every pin takes 2 bits for function
config, where we shall have dts data:
"pinctrl-single,function-mask=<0x3>". In this case, pcs->fmask is 0x3
for all pins for we have only one copy of pcs->fmask in driver. If we
want to configure pin to gpio that controlled by bit[3:2], we shall
have below value set with shifting mask to clear bit[3:2] first, then
set desired value to configure it as gpio.
                    data = pcs->read(pcs->base + offset) &
~(pcs->fmask << pin_pos);
                    data = pcs->read(pcs->base + offset) & ~(0x3 << 2);

>
> Regards,
>
> Tony
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Tony Lindgren July 7, 2015, 7:42 a.m. UTC | #3
* Jun Nie <jun.nie@linaro.org> [150706 18:59]:
> 2015-07-06 23:42 GMT+08:00 Tony Lindgren <tony@atomide.com>:
> > * Jun Nie <jun.nie@linaro.org> [150706 06:59]:
> >> Support GPIO for one register control multiple pins case
> >> with calculating register offset first, then bit offset.
> >>
> >> Signed-off-by: Jun Nie <jun.nie@linaro.org>
> >> ---
> >>  drivers/pinctrl/pinctrl-single.c | 22 ++++++++++++++++++----
> >>  1 file changed, 18 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
> >> index 13b45f2..4f23ef0 100644
> >> --- a/drivers/pinctrl/pinctrl-single.c
> >> +++ b/drivers/pinctrl/pinctrl-single.c
> >> @@ -494,7 +494,7 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
> >>       struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
> >>       struct pcs_gpiofunc_range *frange = NULL;
> >>       struct list_head *pos, *tmp;
> >> -     int mux_bytes = 0;
> >> +     int offset, mux_bytes = 0;
> >>       unsigned data;
> >>
> >>       /* If function mask is null, return directly. */
> >> @@ -507,9 +507,23 @@ static int pcs_request_gpio(struct pinctrl_dev *pctldev,
> >>                       || pin < frange->offset)
> >>                       continue;
> >>               mux_bytes = pcs->width / BITS_PER_BYTE;
> >> -             data = pcs->read(pcs->base + pin * mux_bytes) & ~pcs->fmask;
> >> -             data |= frange->gpiofunc;
> >> -             pcs->write(data, pcs->base + pin * mux_bytes);
> >> +             if (pcs->bits_per_mux) {
> >> +                     int pin_pos, byte_num, num_pins_in_register;
> >> +
> >> +                     num_pins_in_register = pcs->width / pcs->bits_per_pin;
> >> +                     byte_num = (pcs->bits_per_pin * pin) / BITS_PER_BYTE;
> >> +                     offset = (byte_num / mux_bytes) * mux_bytes;
> >> +                     pin_pos = pin % num_pins_in_register;
> >> +                     pin_pos *= pcs->bits_per_pin;
> >> +                     data = pcs->read(pcs->base + offset) &
> >> +                             ~(pcs->fmask << pin_pos);
> >> +                     data |= (frange->gpiofunc & pcs->fmask) << pin_pos;
> >
> > I don't quite follow you here.. The pcs->fmask is for the whole register,
> > so I think the fmask should be checked the same way in this case also:
> >
> >                         data = pcs->read(pcs->base + offset) & ~pcs->fmask;
> >                         ...
> >
> > I don't think we can safely assume the fmask would behave differently
> > in this case.
> 
> My understanding to bits_per_mux flags here is that one 32bits
> register shall control 16 pins if every pin takes 2 bits for function
> config, where we shall have dts data:
> "pinctrl-single,function-mask=<0x3>".

Hmm function-mask needs to be for register-width to avoid confusion
and to avoid trying to write to register reserved bits. It seems we
need a new property here in addition to function-mask, and also need to
correct the function-mask usage.

The confusion seems to be introduced in 4e7e8017a80e ("pinctrl:
pinctrl-single: enhance to configure multiple pins of different
modules").

> In this case, pcs->fmask is 0x3 for all pins for we have only one copy
> of pcs->fmask in driver. If we want to configure pin to gpio that
> controlled by bit[3:2], we shall have below value set with shifting
> mask to clear bit[3:2] first, then set desired value to configure it
> as gpio.
>                     data = pcs->read(pcs->base + offset) &
> ~(pcs->fmask << pin_pos);
>                     data = pcs->read(pcs->base + offset) & ~(0x3 << 2);

Yeah OK we need some new property to deal with this. And need to
fix up 4e7e8017a80e usage and ideally get rid of of all the if
(pcs->bits_per_mux) else confusion. 

Regards,

Tony

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Patch
diff mbox

diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
index 13b45f2..4f23ef0 100644
--- a/drivers/pinctrl/pinctrl-single.c
+++ b/drivers/pinctrl/pinctrl-single.c
@@ -494,7 +494,7 @@  static int pcs_request_gpio(struct pinctrl_dev *pctldev,
 	struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
 	struct pcs_gpiofunc_range *frange = NULL;
 	struct list_head *pos, *tmp;
-	int mux_bytes = 0;
+	int offset, mux_bytes = 0;
 	unsigned data;
 
 	/* If function mask is null, return directly. */
@@ -507,9 +507,23 @@  static int pcs_request_gpio(struct pinctrl_dev *pctldev,
 			|| pin < frange->offset)
 			continue;
 		mux_bytes = pcs->width / BITS_PER_BYTE;
-		data = pcs->read(pcs->base + pin * mux_bytes) & ~pcs->fmask;
-		data |= frange->gpiofunc;
-		pcs->write(data, pcs->base + pin * mux_bytes);
+		if (pcs->bits_per_mux) {
+			int pin_pos, byte_num, num_pins_in_register;
+
+			num_pins_in_register = pcs->width / pcs->bits_per_pin;
+			byte_num = (pcs->bits_per_pin * pin) / BITS_PER_BYTE;
+			offset = (byte_num / mux_bytes) * mux_bytes;
+			pin_pos = pin % num_pins_in_register;
+			pin_pos *= pcs->bits_per_pin;
+			data = pcs->read(pcs->base + offset) &
+				~(pcs->fmask << pin_pos);
+			data |= (frange->gpiofunc & pcs->fmask) << pin_pos;
+		} else {
+			offset = pin * mux_bytes;
+			data = pcs->read(pcs->base + offset) & ~pcs->fmask;
+			data |= frange->gpiofunc;
+		}
+		pcs->write(data, pcs->base + offset);
 		break;
 	}
 	return 0;