[PATCH] pinctrl: meson: fix drive strength register and bit calculation

[PATCH] pinctrl: meson: fix drive strength register and bit calculation

[hhk7734]

From: Hyeonki Hong <hhk7734@gmail.com>

If a GPIO bank has greater than 16 pins, PAD_DS_REG is split into two
registers. However, when register and bit were calculated, the first
register defined in the bank was used, and the bit was calculated based
on the first pin. This causes problems in setting the driving strength.

Solved the problem by changing the bit using a mask and selecting the
next register when the bit exceeds 15.

Signed-off-by: Hyeonki Hong <hhk7734@gmail.com>
---
 drivers/pinctrl/meson/pinctrl-meson.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
index bbc919bef2bf..ef66239b7df5 100644
--- a/drivers/pinctrl/meson/pinctrl-meson.c
+++ b/drivers/pinctrl/meson/pinctrl-meson.c
@@ -98,6 +98,13 @@ static void meson_calc_reg_and_bit(struct meson_bank *bank, unsigned int pin,

 	*reg = desc->reg * 4;
 	*bit = desc->bit + pin - bank->first;
+
+	if (reg_type == REG_DS) {
+		if (*bit > 15) {
+			*bit &= 0xf;
+			*reg += 4;
+		}
+	}
 }

 static int meson_get_groups_count(struct pinctrl_dev *pcdev)
--
2.17.1

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Re: [PATCH] pinctrl: meson: fix drive strength register and bit calculation

[Jerome Brunet]

On Wed 10 Jun 2020 at 06:13, hhk7734@gmail.com wrote:

> From: Hyeonki Hong <hhk7734@gmail.com>
>
> If a GPIO bank has greater than 16 pins, PAD_DS_REG is split into two
> registers. However, when register and bit were calculated, the first
> register defined in the bank was used, and the bit was calculated based
> on the first pin. This causes problems in setting the driving strength.
>
> Solved the problem by changing the bit using a mask and selecting the
> next register when the bit exceeds 15.

This fixes the case of GPIOX on g12 which goes up to 18 yes but the same
problem will happen again a if bank ever goes past 31 pins. In such case
the problem would apply to all reg types.

I would prefer if it was solved in a more generic fashion, like defining
a "stride" table with the values of each reg type. This table can common
to all aml SoCs for now but eventually it probably need to be SoC
specific.

This would allow to :
A) handle the case you are reporting in a generic (future proof) way
B) remove the weird "bit = bit << 1;" calc in place in the get/set of
the drive strengh pinconf

>
> Signed-off-by: Hyeonki Hong <hhk7734@gmail.com>
> ---
>  drivers/pinctrl/meson/pinctrl-meson.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
> index bbc919bef2bf..ef66239b7df5 100644
> --- a/drivers/pinctrl/meson/pinctrl-meson.c
> +++ b/drivers/pinctrl/meson/pinctrl-meson.c
> @@ -98,6 +98,13 @@ static void meson_calc_reg_and_bit(struct meson_bank *bank, unsigned int pin,
>
>  	*reg = desc->reg * 4;
>  	*bit = desc->bit + pin - bank->first;
> +
> +	if (reg_type == REG_DS) {
> +		if (*bit > 15) {
> +			*bit &= 0xf;
> +			*reg += 4;
> +		}
> +	}
>  }
>
>  static int meson_get_groups_count(struct pinctrl_dev *pcdev)


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[PATCH] pinctrl: meson: fix drive strength register and bit calculation

[Hyeonki Hong]

On Wed, Jun 10, 2020 at 03:09:42PM +0200, Jerome Brunet wrote:
> 
> On Wed 10 Jun 2020 at 06:13, hhk7734@gmail.com wrote:
> 
> > From: Hyeonki Hong <hhk7734@gmail.com>
> >
> > If a GPIO bank has greater than 16 pins, PAD_DS_REG is split into two
> > registers. However, when register and bit were calculated, the first
> > register defined in the bank was used, and the bit was calculated based
> > on the first pin. This causes problems in setting the driving strength.
> >
> > Solved the problem by changing the bit using a mask and selecting the
> > next register when the bit exceeds 15.
> 
> This fixes the case of GPIOX on g12 which goes up to 18 yes but the same
> problem will happen again a if bank ever goes past 31 pins. In such case
> the problem would apply to all reg types.
> 
> I would prefer if it was solved in a more generic fashion, like defining
> a "stride" table with the values of each reg type. This table can common
> to all aml SoCs for now but eventually it probably need to be SoC
> specific.
> 
> This would allow to :
> A) handle the case you are reporting in a generic (future proof) way
> B) remove the weird "bit = bit << 1;" calc in place in the get/set of
> the drive strengh pinconf

If all amlogic SoC has same register style, I think the code below is fine.

static const unsigned int meson_bit_strides[] = {
	0, 0, 0, 0, 0, 1, 0
};

static void meson_calc_reg_and_bit(struct meson_bank *bank, unsigned int pin,
				   enum meson_reg_type reg_type,
				   unsigned int *reg, unsigned int *bit)
{
	struct meson_reg_desc *desc = &bank->regs[reg_type];

	*bit = (desc->bit + pin - bank->first) << meson_bit_strides[reg_type];
	*reg = (desc->reg + (*bit / 32)) * 4;
	*bit &= 0x1f;
}

How about this?

> >
> > Signed-off-by: Hyeonki Hong <hhk7734@gmail.com>
> > ---
> >  drivers/pinctrl/meson/pinctrl-meson.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
> > index bbc919bef2bf..ef66239b7df5 100644
> > --- a/drivers/pinctrl/meson/pinctrl-meson.c
> > +++ b/drivers/pinctrl/meson/pinctrl-meson.c
> > @@ -98,6 +98,13 @@ static void meson_calc_reg_and_bit(struct meson_bank *bank, unsigned int pin,
> >
> >  	*reg = desc->reg * 4;
> >  	*bit = desc->bit + pin - bank->first;
> > +
> > +	if (reg_type == REG_DS) {
> > +		if (*bit > 15) {
> > +			*bit &= 0xf;
> > +			*reg += 4;
> > +		}
> > +	}
> >  }
> >
> >  static int meson_get_groups_count(struct pinctrl_dev *pcdev)
> 

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Re: [PATCH] pinctrl: meson: fix drive strength register and bit calculation

[Jerome Brunet]

On Thu 11 Jun 2020 at 07:40, Hyeonki Hong <hhk7734@gmail.com> wrote:

> On Wed, Jun 10, 2020 at 03:09:42PM +0200, Jerome Brunet wrote:
>> 
>> On Wed 10 Jun 2020 at 06:13, hhk7734@gmail.com wrote:
>> 
>> > From: Hyeonki Hong <hhk7734@gmail.com>
>> >
>> > If a GPIO bank has greater than 16 pins, PAD_DS_REG is split into two
>> > registers. However, when register and bit were calculated, the first
>> > register defined in the bank was used, and the bit was calculated based
>> > on the first pin. This causes problems in setting the driving strength.
>> >
>> > Solved the problem by changing the bit using a mask and selecting the
>> > next register when the bit exceeds 15.
>> 
>> This fixes the case of GPIOX on g12 which goes up to 18 yes but the same
>> problem will happen again a if bank ever goes past 31 pins. In such case
>> the problem would apply to all reg types.
>> 
>> I would prefer if it was solved in a more generic fashion, like defining
>> a "stride" table with the values of each reg type. This table can common
>> to all aml SoCs for now but eventually it probably need to be SoC
>> specific.
>> 
>> This would allow to :
>> A) handle the case you are reporting in a generic (future proof) way
>> B) remove the weird "bit = bit << 1;" calc in place in the get/set of
>> the drive strengh pinconf
>
> If all amlogic SoC has same register style, I think the code below is fine.
>
> static const unsigned int meson_bit_strides[] = {
> 	0, 0, 0, 0, 0, 1, 0
> };

 the table above is the shift, not the stride.
 Maybe 'width' is a better description
 I would prefer if it was { 1, 1, 1, 1, 1, 2, 1 } and adjust the caculation

A part from this, your proposition is exactly what I meant :) Thx

>
> static void meson_calc_reg_and_bit(struct meson_bank *bank, unsigned int pin,
> 				   enum meson_reg_type reg_type,
> 				   unsigned int *reg, unsigned int *bit)
> {
> 	struct meson_reg_desc *desc = &bank->regs[reg_type];
>
> 	*bit = (desc->bit + pin - bank->first) << meson_bit_strides[reg_type];
> 	*reg = (desc->reg + (*bit / 32)) * 4;
> 	*bit &= 0x1f;
> }
>
> How about this?
>
>> >
>> > Signed-off-by: Hyeonki Hong <hhk7734@gmail.com>
>> > ---
>> >  drivers/pinctrl/meson/pinctrl-meson.c | 7 +++++++
>> >  1 file changed, 7 insertions(+)
>> >
>> > diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
>> > index bbc919bef2bf..ef66239b7df5 100644
>> > --- a/drivers/pinctrl/meson/pinctrl-meson.c
>> > +++ b/drivers/pinctrl/meson/pinctrl-meson.c
>> > @@ -98,6 +98,13 @@ static void meson_calc_reg_and_bit(struct meson_bank *bank, unsigned int pin,
>> >
>> >  	*reg = desc->reg * 4;
>> >  	*bit = desc->bit + pin - bank->first;
>> > +
>> > +	if (reg_type == REG_DS) {
>> > +		if (*bit > 15) {
>> > +			*bit &= 0xf;
>> > +			*reg += 4;
>> > +		}
>> > +	}
>> >  }
>> >
>> >  static int meson_get_groups_count(struct pinctrl_dev *pcdev)
>> 


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