Re: [PATCH V2 1/2] gpio: pmic-eic-sprd: Two-dimensional arrays maintain pmic eic

[Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>]

On 9/27/2023 5:24 PM, Chunyan Zhang wrote:
> On Wed, 27 Sept 2023 at 17:04, Baolin Wang
> <baolin.wang@xxxxxxxxxxxxxxxxx> wrote:
> > On 9/21/2023 8:25 PM, Wenhua Lin wrote:
> > > A bank PMIC EIC contains 16 EICs, and the operating registers
> > > are BIT0-BIT15, such as BIT0 of the register operated by EIC0.
> > > Using the one-dimensional array reg[CACHE_NR_REGS] for maintenance
> > > will cause the configuration of other EICs to be affected when
> > > operating a certain EIC. In order to solve this problem, the register
> > > operation bits of each PMIC EIC are maintained through the two-dimensional
> > > array reg[SPRD_PMIC_EIC_NR][CACHE_NR_REGS] to avoid mutual interference.
> >
> > LGTM. And this also deserves a Fixes tag.
>
> Do we really need a two-dimensional array to save 16-bit value?

I also considering this, but after more thinking, I think this patch is 
a simple fix.

Now I realized the problem is that, if we use one array to cache a bank 
of EICs' status, the pmic_eic->reg[] array can contain incorrect 
configuration for other EICs in the same bank.

Yes, we can have another fix, for example, setting the pmic_eic->reg[] 
to some invalid values (maybe -1) in sprd_pmic_eic_bus_sync_unlock() 
after setting one EIC. Thus when setting another EIC, we can validate if 
the cached reg is a valid value, if not, we do not need to set the 
register. But like I said above, this seems more complicated.

> > Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
> >
> > > Signed-off-by: Wenhua Lin <Wenhua.Lin@xxxxxxxxxx>
> > > ---
> > >    drivers/gpio/gpio-pmic-eic-sprd.c | 21 +++++++++++----------
> > >    1 file changed, 11 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/drivers/gpio/gpio-pmic-eic-sprd.c b/drivers/gpio/gpio-pmic-eic-sprd.c
> > > index c3e4d90f6b18..442968bb2490 100644
> > > --- a/drivers/gpio/gpio-pmic-eic-sprd.c
> > > +++ b/drivers/gpio/gpio-pmic-eic-sprd.c
> > > @@ -57,7 +57,7 @@ struct sprd_pmic_eic {
> > >        struct gpio_chip chip;
> > >        struct regmap *map;
> > >        u32 offset;
> > > -     u8 reg[CACHE_NR_REGS];
> > > +     u8 reg[SPRD_PMIC_EIC_NR][CACHE_NR_REGS];
> > >        struct mutex buslock;
> > >        int irq;
> > >    };
> > > @@ -151,8 +151,8 @@ static void sprd_pmic_eic_irq_mask(struct irq_data *data)
> > >        struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
> > >        u32 offset = irqd_to_hwirq(data);
> > >
> > > -     pmic_eic->reg[REG_IE] = 0;
> > > -     pmic_eic->reg[REG_TRIG] = 0;
> > > +     pmic_eic->reg[offset][REG_IE] = 0;
> > > +     pmic_eic->reg[offset][REG_TRIG] = 0;
> > >
> > >        gpiochip_disable_irq(chip, offset);
> > >    }
> > > @@ -165,8 +165,8 @@ static void sprd_pmic_eic_irq_unmask(struct irq_data *data)
> > >
> > >        gpiochip_enable_irq(chip, offset);
> > >
> > > -     pmic_eic->reg[REG_IE] = 1;
> > > -     pmic_eic->reg[REG_TRIG] = 1;
> > > +     pmic_eic->reg[offset][REG_IE] = 1;
> > > +     pmic_eic->reg[offset][REG_TRIG] = 1;
> > >    }
> > >
> > >    static int sprd_pmic_eic_irq_set_type(struct irq_data *data,
> > > @@ -174,13 +174,14 @@ static int sprd_pmic_eic_irq_set_type(struct irq_data *data,
> > >    {
> > >        struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
> > >        struct sprd_pmic_eic *pmic_eic = gpiochip_get_data(chip);
> > > +     u32 offset = irqd_to_hwirq(data);
> > >
> > >        switch (flow_type) {
> > >        case IRQ_TYPE_LEVEL_HIGH:
> > > -             pmic_eic->reg[REG_IEV] = 1;
> > > +             pmic_eic->reg[offset][REG_IEV] = 1;
> > >                break;
> > >        case IRQ_TYPE_LEVEL_LOW:
> > > -             pmic_eic->reg[REG_IEV] = 0;
> > > +             pmic_eic->reg[offset][REG_IEV] = 0;
> > >                break;
> > >        case IRQ_TYPE_EDGE_RISING:
> > >        case IRQ_TYPE_EDGE_FALLING:
> > > @@ -222,15 +223,15 @@ static void sprd_pmic_eic_bus_sync_unlock(struct irq_data *data)
> > >                        sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_IEV, 1);
> > >        } else {
> > >                sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_IEV,
> > > -                                  pmic_eic->reg[REG_IEV]);
> > > +                                  pmic_eic->reg[offset][REG_IEV]);
> > >        }
> > >
> > >        /* Set irq unmask */
> > >        sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_IE,
> > > -                          pmic_eic->reg[REG_IE]);
> > > +                          pmic_eic->reg[offset][REG_IE]);
> > >        /* Generate trigger start pulse for debounce EIC */
> > >        sprd_pmic_eic_update(chip, offset, SPRD_PMIC_EIC_TRIG,
> > > -                          pmic_eic->reg[REG_TRIG]);
> > > +                          pmic_eic->reg[offset][REG_TRIG]);
> > >
> > >        mutex_unlock(&pmic_eic->buslock);
> > >    }